Browse Topic: Manifolds

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Topology Optimization of Liquid Flow Manifolds for Flow Resistance Reduction in EV Thermal Management2026-99-08657/30/2026
In order to reduce flow resistance loss in EV thermal management systems, this research builds a comprehensive computational process. The study used an advanced three-dimensional topology optimization technology integrating detailed fluid flow analysis with an adjoint sensitivity solver. This integrated computational approach helps systematic analysis of the complete design region. Thus, the internal flow channels with high resistance can be rearranged. The optimization target was set to minimize total pressure drop under defined operational parameters in real driving conditions. Through iterative calculation, the study successfully created three flow manifolds with different geometric shapes; each flow channel has its own distinct source of high resistance. The results show that the optimization effect is quite good, compared with the traditional manifold developed based on engineering experience; these optimized designs have reduced the pressure drop by 27%, 41%, and 74%, respectively. Beyond these quantitative pressure reduction data, detailed flow field analysis revealed that the optimized manifolds promote substantially improved hydrodynamic characteristics. The optimized internal channels generate more uniform velocity profiles, effectively diminish spatial velocity variations, and restrain vortex formation and recirculation zones. These useful flow field enhancements collectively contribute to a dramatic reduction in energy dissipation. This improves the thermodynamic efficiency of the thermal management system effectively. In order to conduct a more comprehensive verification, the optimized manifold was evaluated under various non-design operating conditions. These three designs consistently maintained stable performance characteristics and their low resistance properties in operating scenarios different from the original conditions, compared to the original manifold. Its stable performance under variable conditions shows the effectiveness of the topology-optimized methods and shows its broad operational adaptability. This is of great significance for the automotive application field, as the operating conditions in this field are often changing.
Liang, Zhixuan, Tian, Ran, Ye, Xiaokang, Wei, Mingshan, Sun, Xiaoxia, Shen, Lili
Methane Emission Mitigation in Large-Bore Dual-Fuel Engines via Negative Valve Overlap Diesel Injection: Thermochemical Pathways and Reactivity Control2026-37-00456/9/2026
Low-load natural gas–diesel reactivity controlled compression ignition (RCCI) in medium-speed marine engines is constrained by an insufficient charge thermal state. This limitation leads to partial fuel oxidation, producing high methane emissions. This work evaluates the use of negative valve overlap (NVO) combined with NVO diesel injection as an in-cylinder reactivity enhancement strategy. The simulation study was performed using the University of Vaasa’s advanced thermo-kinetic multi-zone model (UVATZ), extended for reactive simulations during NVO. The extended framework was validated against test-bench data from a prototype Wärtsilä 6L20 dual-fuel engine operating in RCCI mode. The baseline low-load operating point for reforming simulations was defined by reducing the intake manifold temperature to replicate conditions close to partial misfire with 52% combustion efficiency. The parametric sweeps of NVO injection timing and ratio showed that the strategy can be used for in-cycle fast thermal management, effectively restoring complete combustion on an individual cycle basis. In simulated conditions, the best performance was obtained with an NVO injection ratio of 0.3, with the injection scheduled before top dead center. In contrast, increasing the NVO fraction beyond ~0.3 provided no benefit and led to complete misfire due to excessive reduction of main-event high-reactivity fuel. The simulations revealed a coupled thermal–chemical control mechanism. Early NVO injections stabilize combustion through recompression heat release and an increased next-cycle intake valve closing temperature. Sufficiently late injections stabilize combustion by carrying unreacted diesel into the subsequent cycle. Injections near NVO TDC primarily undergo fuel conversion to CO, H2O, and unsaturated light/mid-range hydrocarbons with negligible thermal boost, yielding an overall reactivity deficit.
Soleimani, Amir, Nurmi, Mikael, Hunicz, Jacek, Kim, Jeyoung, Hyvonen, Jari, Mikulski, Maciej
Risk Assessment of Cold Side Components Using Quick Modal Analysis Correlation Technique2026-26-04411/16/2026
Modal analysis is performed to determine the natural frequencies and mode shapes of a structure or system. It helps engineers understand how a system vibrates and how external forces, such as mechanical loads, might excite unwanted resonances. To check the stresses due to vibration inputs, certain G levels are assumed, and stresses are scaled to those vibration levels. This gives an understanding of the stresses of components with respect to its EFR limit and design margins are calculated. But, assumed acceleration levels in pre-prototype stage level can over predict or under predict the design margins. A quick modal analysis correlation technique can be used by using test measured accelerations conducted at prototype stage of the program. In this work, a modal analysis correlation technique is used to perform risk assessment of intake manifold. The intake manifold failed due to high vibration levels which were not captured from high cycle fatigue analysis with assumed G-level. In the modal analysis correlation technique, an effort is made to align the mode shape and frequency of the intake system and then with measured accelerations high cycle fatigue design margins are calculated. This gave accurate high stress location where in actual intake manifold was failed. Further design recommendations were suggested based on stress nature and location. This technique can be a quick risk assessment solution as only modal analysis with few peripheral components are required to be modelled in FEA analysis. This paper explores modal analysis correlation techniques, detailing the steps for aligning the mode shape and frequency of a system, while also addressing the limitations of the method.
Bale, Shrikant Bhaskar, Bawache, Krushna
Comprehensive Engine Testing Methodologies for Hydrogen Internal Combustion Engine Validation with Combustion & Performance Evaluation Techniques2026-26-02561/16/2026
Validation of hydrogen-fuelled internal combustion engine (H2 ICE) is critical to assess its feasibility as sustainable transportation with zero carbon emissions. This experimental analysis conducted on Ashok Leyland’s 6cylinder 2V engine to evaluate the engine performance & durability with hydrogen fuel. Combustion behaviour of hydrogen ICE needs to be closely monitored during continuous operation of validation testing, due to its unique properties compared to other conventional fuels. During engine run, a pre-ignition source can cause knock event leading to instant failure of critical parts like piston assembly, spark plug, liner, valves & cylinder head. Also, hotspots inside IMF leads to backfire affecting the air intake & fuel injection assembly. This study emphasizes the significance of precise instrumentation of thermocouples across engine on cylinder head, intake manifold & exhaust manifold, to detect performance detoriation and combustion abnormalities causing knocking & backfire. Crankcase ventilation system design plays a critical role in evacuating the blowby gas from engine block. This paper explains methodology to measure the moisture condensation from blowby gas, as it leads to oil emulsification. Experimental data shows variation in inlet manifold air temperature directly impacts engine power as H2 ICE operates at higher stoichiometric ratio. Increase in air intake temperature from turbo compressor out is a result of barometric temperature and pressure variation. This measurement is critical to understand the engine performance variation in real-time operating condition. Hence validation of H2 ICE necessitates a specialized instrumentation during testing to monitor the performance parameters and hardware detoriation. This research provides critical insights into the procedural adaptations required for H2 ICE testing and validation by integrating frugal instrumentation with experimental analysis. This study offers a robust framework for assessing engine performance, reducing operational risks, and ensuring test results reliability. These findings contribute to the design & development of hydrogen-fuelled engines, facilitating their adoption as a sustainable alternative for transportation while addressing durability, emissions, and regulatory compliance challenges.
Vasudevan, Sindhuja, J, Narayana Reddy, Bolar, Yogesh Ganesh, Pandey, Sunil, N, Harish, N R, Varatharaj, Karthikeyan, K, Kumar D, Kishore
Improving Cold Start and Transient Performance of Medium BMEP CEV Stage V Engines at Low Ambient Temperature and Pressure2026-26-01421/16/2026
Meeting the stringent emissions norms of CEV stage V for medium BMEP engines, CI engines present significant challenges, particularly concerning cold startability. Low ambient temperatures and pressures intensify the cold start difficulties which are characterized by prolonged cranking, incidences of misfiring, compromised transient response and overall engine performance. This paper highlights the strategies and technologies employed to enhance cold start and transient performance of medium BMEP engines under such demanding environmental conditions. Investigations were conducted up to an altitude of 4500m and ambient temperatures as low as-20°C, utilizing only air heater at intake manifold as the sole cold start aid. This cost effective approach is integrated with an optimized combustion chamber design, along with minimal pilot injection timing and quantity to facilitate smooth ignition and stable combustion during cold start. The paper also explore the techniques to improve the engine transient response, minimize smoke and PM emissions during speed and load changes under these extreme environmental conditions, such as turbocharger response, fuel delivery control, and dynamic injection timing and rail pressure adjustments.
Saxena, Harshit, Lokare, Prasad, Santhosh, Ajith, Gandhi, Naresh, Shinde, Prashant
A Mathematical Modelling Approach Based on Artificial Neural Network for Estimation of Key Parameters in Internal Combustion Engine2026-26-06591/16/2026
In a conventional powertrain driven by Internal combustion (IC) engines, various sensors are used to monitor engine performance and emissions. Along with physical sensors, virtual sensors or modelled values of key parameters play an important role for enabling various diagnostics strategies and engine monitoring. Conventional strategies for modelling incorporate the use of regression models, map-based models and physics-based models which have few drawbacks in terms of accuracy and model calibrations efforts. Data driven models or neural networks have fairly better accuracy and reliability for estimating complex parameters. Representing the neural network with a mathematics-based model would help to eliminate drawbacks associated with conventional modelling approach. The proposed methodology uses artificial intelligence technique called artificial neural network (ANN) for estimation of temperature at turbine inlet (TTI) in typical diesel engine. The data driven model is built in Python. Modelling process of ANN comprises of feature selection, data scaling, and training/testing with predefined set of neurons in each layer. Once the ANN is trained, weights and biases of each neuron and intermediate connections are obtained. The relationship between each neuron in the input layer, hidden layers and output layers is established using the weights and biases. Subsequently a mathematical model was built using the above information to replicate the results obtained by ANN. For initial validation, the ANN was tested with real world vehicle data. Statistical analysis and time series analysis between TTI and estimated TTI was done for different engine operating conditions. Based on the analysis, it was concluded that the results obtained from ANN demonstrate high accuracy. Furthermore, the mathematical model was validated against the results obtained by ANN. An exact match was observed between the ANN output and the results obtained by mathematical model.
Jagtap, Virendra Shashikant, Shejwal, Sanket, Mitra, Partha
Optimization of Negative Crankcase Pressure Mechanism to Minimize Oil Pumping into Combustion Chamber and Ensure Particulate Number Compliance in Euro VI Emission for Natural Aspirated Gas Engine2026-26-02231/16/2026
Emissions regulations, such as Euro VI, drives the Automotive industry to innovate continuously in Engine development. One significant challenge is the engine oil pumping from the crankcase into the combustion chamber, where it participates in combustion, which contributes to increased Particulate Numbers and fails to meet Euro VI emission compliance. This issue is most noticeable during engine idling and motoring conditions. During this time, a higher negative pressure difference develops between the intake manifold, which is acting above the combustion chamber and the engine crankcase. This pressure difference drives oil-laden blow-by aerosols past piston rings during the intake stroke and through the valve stem seals, allowing oil into the combustion chamber. The impact of the pressure difference between the intake manifold and crankcase was studied by varying the crankcase pressure through crankcase ventilation system. The results confirm that oil entry into the combustion chamber, contributing to combustion, occurs primarily through the piston rings, contributing to increase in Particulate Number (PN). To address this issue, it becomes necessary to introduce a mechanism that optimizes negative crankcase pressure across varying engine operating conditions. By reducing the pressure difference between the intake manifold and crankcase, this mechanism prevents oil entering the combustion chamber, thereby minimizing Particulate Number emissions and ensuring Euro VI compliance. This study focuses on the development and implementation of a negative crankcase pressure control system via the crankcase ventilation system. Through targeted optimization, it provides an effective way to control oil pumping into the combustion chamber, thereby enhancing emission control and advancing the development of cleaner Naturally Aspirated Gas engines.
R, Mahesh Bharathi, Bondfale, Shubham, Jeyaprakasan, Dharoon Gautham
Failure Analysis and Redesign of a 3D Printed Intake Manifold in a Formula SAE Racing Team Using High-Performance Polymers2025-36-023412/18/2025
Fused filament fabrication (FFF) 3D printing has proven to be an affordable method for producing customized and lightweight parts and an accessible method to validate new composite materials. As a rapid prototyping method, it can be used to manufacture and replace defective and/or damaged parts in places with limited infrastructure or logistical support. However, the layer-by-layer deposition inherent to the FFF process introduces anisotropy and residual stresses, which can compromise part performance under high temperatures or vibrational loads. This article aims to analyze the failure of a 3D printed intake runner and address the problems found. The analyzed part was 3D printed in acrylonitrile butadiene styrene (ABS), which had a high volumetric contraction during the printing process. Although ABS exhibits a high heat deflection temperature (HDT) compared to other polymers, prolonged exposure to elevated temperatures during operation led to unintentional embrittlement, reducing interlayer adhesion and releasing residual stress through deformation. The appearance of softened polymer at the intake connections indicates that there was a chemical reaction of polymer with fuel components (hydrocarbons). This chemical reaction, associated with exposure to the high operational temperature during long periods, was the most likely root causes of the failure of the part (combined effects). A new material (Tritan HT) was evaluated for its mechanical strength and the redesigned part was then produced using the Sovol SV 04 printer (a dual extruder 3D printer), replacing the original material (ABS) with the new filament. This change offers lower chemical reactivity with hydrocarbons and presents high HDT temperatures, which allows the integrity of the internal structure of the part even at high temperatures. Assembly tests have shown that the greater sturdiness provided from optimized printing parameters and Tritan HT filament as an unexpected benefit by allowing higher elastic deformation than the original part with ABS. This benefit reduced the risk of damage to the part and surrounding components and helped to ensure the formula SAE team's competitive capacity.
Oliveira, Vinícius de, Horiuchi, Lucas Nao, Magalhaes, Gabriel, Alcantara, Nathan de, Gonçalves, Ana Paula, Souza, Mariana, Polkowski, Rodrigo
Methodology Development of an Internal Combustion Engine Intake Manifold Analysis via 1D-3D Coupled Simulation2025-36-015812/18/2025
The objective of this work was to develop an analysis methodology for engine intake manifolds in Formula SAE prototypes, addressing the three-dimensional (3D) airflow characteristics within these complex geometries. Air flow modelling via one-dimensional (1D) computational fluid dynamics (CFD) software does not capture properly the manifold airflow characteristics and may lead to unrealistic engine performance prediction. On the other hand, the use of purely 3D-CFD simulations of intake manifold isolated from engine, without adequate boundary conditions, also does not conduct to realistic behavior. To address these issues, a 1D-CFD transient analysis model was created using GT-Suite software from Gamma Technologies, which provided boundary conditions for the engine’s airflow demand to Ansys Fluent, the 3D-CFD simulation software. Ansys Fluent, in turn, returned the actual conditions imposed by the manifold geometry to the 1D model, enabling a bidirectional simulation that enhances the evaluation of the engine’s functional parameters and internal components. This methodology relies on the characterization of dimensional engine parameters, calibration of valve flow coefficients for intake and exhaust valve flow through CFD analysis, mesh convergence studies, and appropriate selection of solvers and turbulence models based on expected velocity and mesh size. It aims to improve the team’s understanding of potential optimizations in both engine and intake manifold design, encouraging exploration of enhancements throughout the prototype’s lifecycle. Additionally, it establishes a robust CFD methodology that supports precise design decisions while allowing for future refinements to the approach. The application of this methodology resulted in a more realistic numerical representation of the engine’s operational behavior, facilitating the visualization of various fluid dynamics phenomena, such as velocity and pressure contours, streamlines, and air distribution within the intake manifold under defined operating conditions of engine speed and load. Consequently, it reduced discrepancies in volumetric efficiency and torque calculations compared to standalone 1D simulations.
Piotto, Gustavo Fernando, Santos Souza, Thiago Cavalheri, Foz, Tiago Alcantara, Pegoraro, Bruno Coimbra, Zabeu, Clayton Barcelos
Effect of Hydrogen Injection Timing in a Compression Ignition Engine Operating in Hydrogen Diesel Dual Fuel Mode2025-32-005111/3/2025
Stringent European carbon dioxide (CO2) emission regulations have stimulated the development of alternative technologies such as Dual Fuel (DF), which involves partially replacing fossil fuel with a low-carbon alternative. Hydrogen represents an ideal candidate for DF due to its properties, including the absence of carbon, high flame propagation speed, and high diffusivity. This study analyzes the combustion and performance of a 1.0L, naturally aspirated, three-cylinder in-line compression ignition off-road engine with a 17.5:1 compression ratio, originally equipped with a conventional diesel system and modified for diesel-hydrogen dual fuel operation. Three Port Fuel Injectors (PFI) are installed in the intake manifold for hydrogen injection. Additionally, they are strategically positioned to minimize the volume between the intake valve and injector tip. Tests were conducted at a fixed engine speed of 2000 rpm, varying the engine load from 30% to 85% of maximum torque. The diesel contribution was maintained at 10%, while hydrogen provided the remaining energy, achieving a substitution ratio up to 72%. The analysis showed that hydrogen without diesel doesn't burn efficiently, and the combustion of the air-hydrogen mixture is influenced by diesel injection and excess air in the engine. Subsequently, with the load fixed at 70%, the effect of hydrogen start of injection (SOI) on the engine's air intake flow was studied. The injection window was shifted by 112° crank angle step, avoiding injection near the intake valve closing. The results showed that injections too close to the compression phase, (end of injection equal to 163° crank angle before top dead center), can cause irregular combustion problems.
Rossetti, Salvatore, Mancaruso, Ezio
Hydrogen-Assisted Renewable Fuels RME and HVO in the Compression-Ignition Engine2025-32-004811/3/2025
The article presents the research results on performance, thermodynamic parameters, and toxic exhaust emissions from the combustion in a compression-ignition engine fueled optionally by the hydrotreated vegetable oil (HVO) or the rapeseed methyl ester (RME), both with hydrogen addition. Furthermore, regular diesel fuel was used to obtain the reference data for making comparisons between HVO, RME, and diesel fuel. Hydrogen was injected into the intake manifold of a compression-ignition (CI) engine. Typically, diesel fuel combustion in a CI engine initiates through its self-ignition, usually simultaneously occurring at many points across the engine cylinder. Hydrogen, as a very chemically reactive substance, can promote pre-ignition reactions and accelerate flame kernel formation, shortening the ignition lag. This is crucial for the smooth running of the compression-ignition engine. Hydrogen was added at amounts not exceeding 7% by volume (35% energy content) referred to air sucked into the engine cylinder. As observed, a slightly positive trend in NOx vs. hydrogen addition was observed. It was also found that hydrogen added in small amounts does not form the so-called knock originating from hydrogen rapid combustion, regardless of the diesel knock.
Szwaja, Stanislaw, Juknelevicius, Romualdas, Pukalskas, Saugirdas, Rimkus, Alfredas, Szymanek, Arkadiusz
Design, Optimization and Calibration of a Single-Cylinder, Motorcycle Engine for Integration into a Novel Formula SAE Electric Hybrid Powertrain2025-32-004511/3/2025
The Formula SAE competitions often drive changes in the automotive research field by developing, implementing and emphasizing new technologies for both on-road and on-track applications and by training future engineers, mechanics, logistics and administrative personnel. In this work, the adaptation of a motorcycle, single-cylinder engine for the installation in an electric hybrid car for Formula SAE races is described, focusing on the design of intake and exhaust parts and on the development of the fully open-access Engine Control Unit (ECU) code. In the first part of the work, the 1-D model of the engine is developed and used to design the intake and the exhaust parts needed to make the Formula Student car rules compliant. In particular, the intake manifold and the intake ducts have been designed with the assistance of the engine model to optimize the engine response under transient conditions and to maximize the power. On the other hand, the exhaust line was designed to increase the performance ensuring that it was compatible with the noise regulations imposed by the competition. In the second part of the paper, the experimental activity for the development and calibration of the ECU control strategies is described. The authors highlight how the 1-D engine model helps to reduce the time and cost of the experimental campaign, reducing the number of components that have to be tested. Moreover, the main results of the calibration process are summarized in the last part of the work and the final installation of the engine in the Formula SAE car is shown.
Brusa, Alessandro, Fabbri, Pietro, Shethia, Fenil, Bassani, Davide, Petrone, Boris, Cavina, Nicolo
Impact of Oil Composition on Pre-Ignition in a Hydrogen Engine04-18-03-001810/10/2025
Pre-ignition (PI) is a common issue in internal combustion engines (ICE) with spark ignition. While the various causes have been identified with conventional fuels (such as gasoline or gasoline blends), the causes with hydrogen in ICE are not yet fully understood. This article presents the results of investigations into the influence of seven different lubricating oils on PI in a single-cylinder hydrogen research engine. The variation of two different parameters at two engine speeds were investigated: load and air/fuel mixture. For both variations, the tests start at the same conditions and run until the operating limit of the engine is reached (peak firing pressure, or maximum intake manifold pressure). The PI and knocking PI are investigated, while classifying them according to the peak cylinder pressure. It has been observed that enleanment above λ = 2.4 can lead to higher PI rates, while simultaneously reducing the knocking PI. During the load sweep at 2000 1/min, the highest achievable load among all the oils ranged from IMEP = 19–21 bar, while at 4000 1/min, it ranged from IMEP = 12–15 bar. The performance of the oils showed significantly more disparity at the elevated engine speed. While the impact of different lubricating oils on gasoline engines is rather limited, the outcome of this experiment indicates that in the case of hydrogen engines, oils can have a significant impact on PI. In addition to the oil formulation, different viscosities were also investigated. A lower relative calcium content leads to a much higher PI rate, a lower relative calcium content combined with a higher viscosity did not impact the PI rate. The base oil composition came second in terms of PI influence. The sulfated ash content did not show differences in terms of PI rate. In contrast to gasoline engines, the PI tendency increases with increasing engine speed.
Pehlivanlar, Benjamin, Torkler, Michael, Fischer, Marcus, Göbel, Christoph, Pischinger, Stefan, Maulbetsch, Theo, Nübling, Fritz, Neumann, Stephan
Computational Fluid-Dynamics Analysis of the Effect of Ethanol-Air Mixture Supply in a Heavy-Duty Engine2025-24-00299/7/2025
As part of the Bio-FiRE-for-EVer research project aiming to propose a solution for off-grid charging stations based on the adoption of a reciprocating engine, this study investigated the combustion development and pollutant emissions of an 8.7 l six-cylinder heavy-duty PFI internal combustion engine fueled by ethanol. The reference experimental case features critical issues in the formation of the air-fuel, mainly due to the slow evaporation rate of the alcohol fuel inside the intake manifold via a single point injection, providing a non-uniform and averagely rich (λ=0.89) reactant mixture inside the cylinders. For this purpose, an in-depth analysis of the in-cylinder phenomena is performed by using a CFD solver for the reacting flow. A geometry of the cylinder system complete with intake and exhaust ducts is created for calculations with the three-dimensional Ansys FORTE code. The inclusion of the inlet duct in the computational domain allows the experiencing of several setups of the mixture. Indeed, due to the uncertainties on the complete vaporization of ethanol, experimental data allowed a preliminary validation of the CFD based predictions by considering the presence of liquid fuel fraction (30%) in the inlet duct. After the model calibration, firstly, a more favorable air-fuel ratio condition of λ=1 is examined and then, two alternative solutions are proposed to optimize the engine performance via a multipoint injection upstream of the intake valves but still considering a rich mixture. Based on the results it is demonstrated that the presence of liquid represents a more realistic condition achieving outputs closer to the experimental measurements. The adjustment of air-fuel ratio to a stoichiometric value by only enhancing the amount of air leads to significant improvements in terms of mechanical outputs and CO emissions. Besides, an optimized injection setup can overcome the maldistribution of fuel among cylinders, its incomplete oxidation and reduce the percentage of fuel that remains liquid forming a film on the duct’s wall.
De Robbio, Roberta, Cameretti, Maria Cristina, Palomba, Marco, Tuccillo, Raffaele
Influence of Crankcase Ventilation on Oil-Derived Emissions in a Hydrogen-Fueled Internal Combustion Engine2025-24-00949/7/2025
Crankcase ventilation has a dual influence over hydrogen accumulation in the crankcase and lubricant-derived emissions in hydrogen-fueled internal-combustion engines (H₂-ICEs), yet the magnitude of that influence is still poorly quantified. The present investigation addresses this gap by systematically varying crankcase ventilation flow rate and testing the influence of blowby routing on the emissions of a 2.3 L turbocharged, direct-injection H₂-ICE equipped with a variable-speed sump pump and two oil separators. The engine was held at four steady-state operating points spanning 2 500–3 500 rpm and 5–10 bar brake mean effective pressure, all under ultra-lean mixtures with global excess-air ratios between 2.6 and 3.2. At each point the crankcase ventilation system outlet mass flow was incremented from 6 to 20 kg/h. Elevating the flow diluted the in-crankcase hydrogen concentration from roughly 25 000 ppm to below 10 000 ppm, reducing the mixture to less than one-quarter of the lower flammability limit, while concurrently increasing CO2 emissions, with the most pronounced rise occurring at 3 500 rpm. A complementary ventilation flow mass-balance was used to quantify the blow-by mass flow rate to the crankcase. Particle-number (PN) emissions were found to depend far more on gas routing than on absolute flow: eliminating recirculation to the intake manifold reduced tail-pipe PN by 26–35 % regardless of the ventilation rate. Size-resolved aerosol measurements downstream of the oil separators revealed exclusively sub-micron droplets, confirming that conventional oil separators capture coarse oil yet permit fine aerosol transport. Correlating hydrogen dilution with oil-aerosol breakthrough indicates that safety and emission improvements can be reconciled only by pairing a high crankcase ventilation flow with a high-efficiency sub-micron filtration stage. These insights give practical guidance for designing crankcase-management systems in next-generation lean H₂-ICEs.
Bahhar, Anas, Berthome, Vincent, Mura, Ernesto, Chesse, Pascal, Perrot, Nicolas
AeroSolfd: Advancing Air Quality through Retrofitted Gasoline Particulate Filters – Insights from Laboratory and Real-World Evaluations2025-24-00889/7/2025
This article details the experimental and testing activities of the EU project AeroSolfd, with a particular focus on the project's efforts to reduce combustion-based nanoparticle emissions in exhaust gases for the European fleet of vehicles by developing a GPF retrofit solution. The technical activities undertaken the process of developing such a retrofit are examined in this article. The findings illustrate the viability of reducing nanoparticle levels in gasoline-powered vehicles with the utilization of appropriate GPFs. For this purpose, in addition to a fleet, four vehicles were examined in great detail and underwent the process of obtaining component approval for the particulate filter. The vehicles were measured in a preliminary state, then following the installation of the GPF, and subsequently after several months of continuous field operation. A total of four vehicles were selected for evaluation as a representative subgroup of a larger test fleet of vehicles in the project. These four vehicles were subjected to a series of assessments, including measuring the emissions on a chassis roller test bench and in real-drive experiments with portable emission measurement equipment. The gaseous and nanoparticle emissions were examined in each of these two test cases, and the variants with and without a particle filter as well as the variants before and after the endurance run. Preliminary findings indicate that the retrofitting of gasoline vehicles with minimal modifications can yield notable benefits besides the reduction in air pollution, particularly in the form of nanoparticles.
Engelmann, Danilo, Mayer, Andreas, Comte, Pierre, Rubino, Lauretta, Larsen, Lars
Water Injection Effects on a Heavy-Duty Hydrogen Spark Ignition Engine2025-24-00509/7/2025
Hydrogen engines have gained interest recently, as they present a promising alternative for decarbonizing heavy-duty transport, aligning with carbon neutrality regulations. This study investigates the effects of inlet manifold water injection on a heavy-duty hydrogen-fueled spark ignition single-cylinder engine, focusing on moderating abnormal hydrogen combustion and its impact on performance, thermal efficiency, and exhaust emissions. Water injection has been identified as a potential solution to mitigate the challenges associated with hydrogen combustion, such as pre-ignition and knock, by reducing the reactivity of the mixture (lowering temperature and increasing the dilution). The lower reactivity of the mixture allows running richer lambdas or higher compression ratios without spontaneous preignition, mitigating boosting requirements for full load and transient performance. Experimental results demonstrate that water injection significantly improves engine performance, thermal efficiency, and exhaust emissions. By injecting water into the intake charge, the peak combustion temperature is lowered due to its cooling and dilution effect, leading to a reduction in nitrogen oxide (NOx) exhaust emissions. This also allows a better combustion phasing, because the preignition tendency is reduced, enhancing thermal efficiency and performance. Furthermore, the study explores the possibility of increasing the compression ratio using water injection, to investigate the potential in thermal efficiency. The research highlights water injection effectiveness in controlling hydrogen combustion, allowing the possibility to operate at higher loads, with more compression ratio and less boosting requirements. This paper shows the potential of water injection as a viable strategy to act as an enabler for highly efficient SI heavy duty hydrogen engines capable of high load engine operation and low exhaust emissions, which is critical for heavy-duty applications under real-world conditions.
Peñin Garcia, Alfonso Jose, Valls Claramunt, Carles, Rivas, Manuel, Birnstingl, Johannes, Wieser, Martin, Martin, Jaime, Novella, Ricardo
Manifold Configuration Effects on Root-Mean-Square Turbulent Velocity in a Spark Ignition Engine03-18-05-00297/9/2025
The present study aims to simulate the non-reacting flow within the cylinder of a two-stroke spark ignition internal combustion engine (SIE) utilizing gasoline direct injection (GDI). A computational fluid dynamics (CFD) analysis was employed to forecast the turbulence levels of the in-cylinder flow, including the root-mean-square (RMS) turbulent velocity. The three-dimensional model was developed using ANSYS-FLUENT. The investigation examined the intake manifold inclination angles of 0°, 10°, 20°, 30°, and 40° for two different types of single-intake port engines (I and II) and a single-type double-intake port engines, that are presented at an engine speed of 1500 rpm. The findings revealed that the highest RMS turbulent velocities occurred at a 30° inclination for the double-intake engine, while the single-intake engines (I) and (II) showed peak velocities at 0° and 10°, respectively. Furthermore, in single-intake engine (I), the RMS turbulent velocity was found to be 38.7% greater than that of the double-intake engine, and single-intake engine (II) exhibited a 35% increase compared to single-intake port (I).
Soliman, Mohab, Elbadawy, Ibrahim
“A Comparative Assessment of Port Fuel Injection and Direct Injection of Hydrogen in Internal Combustion Engines: Performance, Efficiency, and Emissions”2025-01-02396/16/2025
With the transition toward low-carbon fuel-based transportation systems, hydrogen is becoming increasingly promising as a sustainable internal combustion engine (ICE) fuel. There are two pathways for introducing hydrogen: Port Fuel Injection (PFI) and Direct Injection (DI) in an engine, which greatly affect performance, efficiency, and emissions. In the Port Fuel Injection (PFI), hydrogen is introduced into the intake manifold and mixed with air before reaching the combustion chamber. This approach is preferred due to its affordability, ease of use, and compatibility with current engine configurations. Because of PFI's more uniform air-fuel mixture, combustion is smoother, and NOx emissions are reduced. On the other hand, it raises the possibility of pre-ignition, particularly when engine loads are high, and a decrease in volumetric efficiency due to a reduction in the volume of intake air as hydrogen replaces it. Direct injection gives exact control over the timing and volume of fuel injected by delivering hydrogen straight into the combustion chamber. This method increases power output, thermal management, and combustion efficiency. Injecting hydrogen closer to the top dead center (TDC) decreases premature ignition. DI also lowers the danger of pre-ignition and knock. Despite these benefits, DI systems are more expensive and complicated, requiring precise control mechanisms and cutting-edge injector technology. The study examines through comparative assessment of the two introduction mechanisms for a country like India and suggests that although DI is better suited for high-performance engines, providing greater efficiency and power, with extra complexity, PFI is favorable for cost-sensitive applications where simplicity and emission reduction are prioritized.
Ahirwar, Sachin, Kumar, Naveen
Indirect Blocked Force Measurement of a Hydraulic Power Pack for Structural Vibration Transmission into an Airframe2025-01-00525/5/2025
Centralization of electrically driven hydraulic power packs into the body of aircraft has increased attention on the noise and vibration characteristics of the system. A hydraulic power pack consists of a pump coupled to an electrical motor, accumulator, reservoir, and associated filter manifolds. In previous studies, the characteristics of radiated acoustic noise and fluid borne noise were studied. In this paper, we focus on the structure-borne forces generated by the hydraulic pump characterized through blocked force measurements. The blocked force of the pump was determined experimentally using an indirect measurement method. The indirect method required operation with part under test fixed to an instrumented receiver structure. Measured operational accelerations on the receiver plate were used in conjunction with transfer function measurements to predict the blocked forces. Blocked forces were validated by comparing directly measured accelerations to predicted accelerations at positions on the receiver plate that were not used for the inverse calculation. To build further confidence in the results, two receiving structures were used to calculate the blocked forces and blocked forces were compared. The determined blocked forces can be used by aircraft OEM’s for further acoustic evaluation.
Smither, Matthew, Tuyls, Zachary, Patel, Pratik, Yan, Xin, Herrin, David
Experimental Study of Port Water Injection System on Single Cylinder Diesel Engine Performance and Exhaust Emission2024-32-00254/18/2025
Vehicle emission standards have become more and more stringent and have driven the development of advanced engine design with low-cost emission control technologies. For small diesel engine which is used in three-wheel (3W) passenger and load carrying vehicles, it was major task to improve lower engine rpm torque and performance to comply with stringent exhaust emissions standard as well, especially for Oxides of Nitrogen (NOx) and Particulate Matter (PM) emissions. Bharat Stage (BS) VI emission standards for three-wheel vehicles was implemented from April 2020 onwards in India. Water injection technology has proven advantageous for low-cost solution with Mechanical fuel injection system on small diesel engines, Intake port water injection is the easiest method to introduce water to engine cylinder, which calls for minimal modification of existing engine structure. In the present study 435cc naturally aspirated DI Diesel engine used for three-wheel vehicle was explored by adding water injection system on engine. Water injection is an effective way to reduce NOx emissions. A series of experiments were carried out on engine test dynamometer as well as on vehicle chassis dynamometer on naturally aspirated single cylinder diesel engine with the modification of intake manifold for adding port water injector and required sensors on engine. Water was injected with multi hole injector into intake manifold at 2 bar pressure to create water mist at late suction stroke. Water injection systems consist of input sensors like engine speed sensor, pressure sensor, temperature sensor which are controlled by electronic controller unit (ECU) to provide metered water injection to engine. Results infer, intake port water injection at late suction stroke is beneficial for NOx emission to meet India BS6 emission norms on Diesel 3-wheeler vehicle. India BS6 emission was met on 3-wheeler vehicle with margin of 36% for CO, 33% for NOx, 24% for HC+NOX and 20% for PM by combination of small percentage of EGR, water injection at 2 bar pressure and Diesel oxidation catalyst.
Syed, Kaleemuddin, Chaudhari, Sandip, Khairnar, Girish, Katariya, Rahul, Jagtap, Pranjal, Bhoite, Vikram
A DEM-FEM Coupled Analysis of Ultrasonic Shot Peening Dynamics and Surface Modification Parameters in Aluminum Alloys2025-01-82394/1/2025
The significant mechanical features of aluminum alloy, including cost-effectiveness, lightweight, durability, high reliability, and easy maintenance, have made it an essential component of the automobile industry. Automobile parts including fuel tanks, cylinder heads, intake manifolds, brake elements, and engine blocks are made of aluminum alloy. The primary causes of its engineering failure are fatigue and fracture. Aluminum alloys' fatigue resistance is frequently increased by surface strengthening methods like ultrasonic shot peening (USP). This article discusses the shot peening dynamics analysis and the influence of ultrasonic shot peening parameters on material surface modification using the DEM-FEM coupling method. Firstly, the projectile motion characteristics under different processes are simulated and analyzed by EDEM. The projectile dynamics characteristics are imported into Ansys software to realize DEM-FEM coupling analysis, and the surface modification characteristics of shot peening materials are obtained. The distribution laws of projectile impact velocity and impact angle are summarized through EDEM simulation of USP with different parameters. At the same time, taking the projectile impact velocity and impact angle as input parameters, combined with ANSYS analysis software, the maximum residual stress and average residual stress of the material under the known peening process conditions are calculated.
Adeel, Muhammad, Azeem, Naqash, Xue, Hongqian, Hussain, Muzammil
Correlation Study of Low-Frequency Engine Order Noise Prediction at Compressor Inlet for a PHEV and Resonator Tuning2025-01-86434/1/2025
Sound pollution has become one of the major environmental concerns for the global automotive industry. Air Induction System (AIS) plays an important role in engine performance and vehicle noise. An ideal design of AIS provides debris-free air for combustion and reduces the engine noise that is heard while snorkeling. This work aims to correlate low-frequency engine order noise prediction at the compressor inlet and snorkel inlet for a 2.0L I4 turbo engine of a Plug-in hybrid vehicle (PHEV) for better acoustic performance without compromising on engine performance. 1D simulation software GT-POWER, Simcenter 3D, and Hypermesh are used for this work. Transmission loss (TL) results with respect to the frequency of the air-box with ducts and intake manifold with charge air cooler are plotted from 0 to 1000 Hz. The air intake system TL results show a good correlation between 3D and 1D till 600 Hz. Compressor and snorkel noise simulation results, especially the firing order and its harmonic orders, are compared with test results from 1500 to 5000 rpm. Helmholtz resonators are deployed on the clean side duct (CSD) to attenuate the snorkel noise. The optimized design shows better acoustic performance than the original design. Deployment of advanced software and experimental methods leads to First Time Right product development by effectively reducing valuable design cycle time and can be further used in research for future vehicle programs.
Dixit, Manish
Neural Network Based Modeling and Model Predictive Control for Reduction in Diesel Emissions2025-01-83694/1/2025
The paper illustrates the process and steps in the development of a neural network-based economic Model Predictive Control (MPC) strategy for reducing diesel engine feed gas emissions. This MPC controller performs fuel limiting and modifies intake manifold pressure and exhaust gas recirculation (EGR) rate set-points to the inner loop air path controller to reduce engine-out oxides of nitrogen (NOx) and Soot emissions. We examine two Recurrent Neural Network (RNN) options for a control-oriented emissions model which are based on a multi-layer perception (MLP) architecture and a long short-term memory (LSTM) architecture. These RNN models are trained for use as prediction models in MPC. Both models are defined in input-output form, assuming that measurements/estimates of current values of NOx and Soot are available. We discuss and compare their training using PyTorch. The formulation of economic MPC is detailed, including the definition of the cost function and soft constraints. Approaches based on interior point methods and sequential quadratic programming for the numerical solution of the underlying optimization problem in MPC are summarized. Closed-loop simulations of the control system and the plant model in GT-Power demonstrate that both methods have the capability to shape engine-out emissions effectively by adjusting weights and constraints in the economic MPC formulation. The solutions with MLP-based and LSTM-based RNN are then compared based on several aspects such as model complexity, training time, tuning, closed-loop performance, and execution time. The closed-loop performance in terms of cumulative NOx and Soot exceeding soft constraints is compared based on Pareto fronts for the respective controller options. Methods to reduce online runtime are also studied. The results highlight the tradeoff between NOx and Soot emissions, and that better open-loop prediction accuracy achieved with the LSTM Neural Network model compared to the MLP model does not necessarily translate into better closed-loop performance when used as a part of the MPC controller.
Zhang, Jiadi, Li, Xiao, Kolmanovsky, Ilya, Tsutsumi, Munechika, Nakada, Hayato
Intake Manifold Parametric Study to Optimize the Design for Acoustics using DFSS Approach2025-01-86514/1/2025
Noise pollution is a significant concern for global automotive industries which propels engineers to evolve new methods to meet passenger comfort and regulatory requirements. The primary purpose of an intake manifold in an automotive vehicle is to allow the passage of clean air for combustion and reduce the noise generated due to engine pulsations. This work proposes a Design for Six Sigma (DFSS) approach to optimize the intake manifold for better acoustic performance without compromising performance for a 3.6 L four-stroke engine for a Plug-in Hybrid electric vehicle (PHEV). Conventionally, intake manifold design has been an iterative process. It involves repetitive testing to arrive at an optimum design. The intake manifold must be designed for better acoustics and engine performance, complicating the design process even more. The DFSS approach has input, output, control, and noise factors. Air-borne noise coming from the engine at different speeds is the input, and the throttle body noise is the output for the analysis. All the design parameters affecting the output are considered the control factors, and the two 3.6 L four-stroke engines with different valve timing are considered the noise factor since the design engineer does not control it. The experimental simulation setup will be based on the different levels of control factors. The simulation work for the throttle body noise was carried out using the GT-POWER software. The throttle body noise data (Sound pressure levels Versus Engine speed) was collected from 800 to 6400 rpm for rumble analysis. The design combination which minimizes the rumble was used as the final design.
Dixit, Manish
Active Unmatched Disturbance Rejection Quasi-Sliding Observer for Electronic Throttle Valve System Based on Backstepping Control03-18-02-00112/10/2025
This study addresses the control problem of the electronic throttle valve (ETV) system in the presence of unmatched perturbations. Most previous works have ignored the effect of actuating motor inductance, which results in an approximated model with a matched perturbation structure. However, if this assumption is not permitted, the ETV model turns into an exact model with unmatched perturbation and the control task becomes more challenging. In this article, a backstepping control design based on a quasi-sliding mode disturbance observer (BS-QSMDO) has been proposed to effectively reject the unmatched perturbation in the ETV system. A rigorous stability analysis has been conducted to prove the ultimate boundedness for disturbance estimation error and tracking error. The key to this proposed observer-based control design is to obtain a robust and chattering-free controller based on a quasi-sliding mode methodology. The proposed quasi-sliding mode observer works to estimate the unmatched perturbation to be then actively rejected by the backstepping controller. Moreover, the observer adds a boundary layer around the sliding manifold to confine the estimation errors within a non-zero layer at the sliding phase, which leads to a considerable reduction of the chattering effect. A comparison study of the proposed BS-QSMDO is made with another backstepping controller based on a nonlinear disturbance observer (BS-NLDO). The numerical results showed the superiority of BS-QSMDO over BS-NLDO in terms of the ultimate bound of estimation and tracking errors. The numerical results showed that the BS-QSMDO could improve the tracking position error, control effort, and estimation errors of unmatched uncertainty by percentages of 26.67%, 1.46% and 92.5%, respectively, as compared to BS-NLDO.
Hameed, Akram Hashim, Al-Samarraie, Shibly Ahmed, Humaidi, Amjad Jaleel
An Integrated Material Science Approach to Evaluate the Viability of Ethoxy Ethane and Rubber Seed (Heavea Brasiliensis) Biodiesel as Sustainable Fuel for Compression Ignition Engines2025-28-01302/7/2025
The primary issues in using pure vegetable oils for internal combustion engines are their high soot output and reduced thermal efficiency. Therefore in the present investigation, a Heavea Brasiliensis biodiesel (HBB) is used as a carbon source of fuel and ethoxy ethane as a combustion accelerator on a compression ignition (CI) engine. In this investigation, an only one cylinder, four-stroke, air-cooled DI diesel engine with a rated output of 4.4 kW at 1500 rpm was utilized. Whereas heavea brasiliensis biodiesel was delivered straightly into the cylinder at almost close to the end of compression stroke and ethoxy ethane was sprayed instantly in the intake manifold in the event of intake stroke. At various loads, the parameter of ethoxy ethane volume rate were optimised. To minimise exhaust emissions, an air plasma spray technology was employed to cover the engine combustion chamber with a thermal barrier coating. Because of its adaptability for high-temperature applications, YSZ (Yttria-stabilized zirconia) was chosen as the coating material. The brake thermal efficiency for a neat HBB is 29.8% and it reached a peak value of 30.5% for ethoxy ethane injection of volume flow rate as 13 cc/min. Also there is a reduction in emissions at all loads except oxides of nitrogen. Smoke emission decreases after ethoxy ethane injection from 6.4 to 5.2 BSN. For HBB, HBB plus ethoxy ethane, and diesel, the HC emission at maximum load is 51 ppm, 47 ppm, and 44 ppm respectively.
Sagaya Raj, Gnana, Natarajan, Manikandan, Pasupuleti, Thejasree
Low-Cost Improvements of an Old Flow Bench and a Discussion of Replacing Orifice Plate by MAF in its Flow Measurement2024-36-007012/20/2024
Recognizing the significant challenges inherent in the analysis of periodic gas flow through reciprocating engines, one can easily appreciate the value of studying the steady flow through cylinder heads, manifolds, and exhaust systems. In these studies, flow benches are the cornerstone of the experimental apparatus needed to validate theoretical results or to perform purely experimental analysis. The Metal-Mechanics Department of IFSC owns a SuperFlow model SF-110 flow bench that has suffered some in house maintenance and received electronic sensors to allow computerized data acquisition. As the essential original sensors in this flow bench were liquid column manometer (for pressure difference across the test subject) and micromanometer (for pressure difference across the orifice plate used to measure the flow), the essential new sensors are electronic differential pressure sensors (installed in parallel with the original ones). In recent decades, however, the use of a mass air flow (MAF) sensor replacing the orifice plate and micromanometer, has been proposed in do it yourself (DIY) flow bench projects presented at the Internet. Some tests of a MAF sensor in the IFSC flow bench are being undertaken to support a discussion of its advantages and disadvantages when compared to the orifice plate. The present work discusses this substitution, as well the electronics and software used in the present version of the in house developed computerized data acquisition system. Preliminary results, difficulties and reliability issues faced by the authors in this development are discussed to share the lessons learned with the readers. The preliminary results presentation also ensues some discussion of the plethora of conflicting definitions and hypotheses that frequently make the flow bench results much more difficult to interpret than they should be.
Vandresen, Marcelo, dos Santos, Luciano Amaury
Performance Enhancement through Air Intake Restrictor Tuning by Fluid Flow Analysis for Formula Vehicle2024-01-520212/10/2024
SAE Formula Student Car Organization mandates the installation of a 20mm diameter restrictor between the throttle body and the engine inlet. The primary objective of this restrictor is to regulate and reduce the mass flow of air into the engine inlet. To achieve this, a venture nozzle has been selected as the ideal component, to decrease air pressure while simultaneously increasing velocity within the intake manifold. This research project focuses on optimizing the restrictor by strategically adjusting the convergent and diverging angles. To enhance the restrictor's efficiency, a comprehensive Computational Fluid Dynamics (CFD) analysis was conducted, exploring a wide range of convergent angles from 12° to 24° and divergent angles spanning from 4° to 8°. The analysis was performed using CFD Fluent within the ANSYS Workbench platform. Following an extensive series of CFD simulations, the optimal angle combination was found to be a converging angle of 20° combined with a divergent angle of 5°, resulting in maximum pressure drop and sonic flow. Also, these angles were carefully selected to maximize airflow velocity, ultimately leading to a significant enhancement in engine performance.
Sathishkumar, A., Soundararajan, R., Ram Kumar, S. K., Mahi Kaarthik, G., Raj Vigneshwar, R., Feroz Ali, L.
Evaluation of Waste Transformer Oil Biodiesel Blend with n-Heptane Additives for Engine Performance under Variable Injection Pressure and Timing2024-01-522312/10/2024
This study examines performance metrics and emission profiles of Kirloskar TV1 CI engine fuelled with blend containing waste transformer oil (WTO) biodiesel (40%), n-Heptane (10%), and diesel (50%) by volume (referred to as WTO40H10D50), with additional 10 lpm of hydrogen induction in the intake manifold. Effects of varied injection of fuel timing (19°, 21°, and 23°bTDC) and injection pressure (170, 210, and 240 bar) of WTO40H10D50 on diesel engine were analyzed at 100% engine loading condition. The findings indicate that an injection timing of 23°bTDC and an IP of 240 bar yield the highest BTE and lowest BSEC, suggesting optimal energy conversion efficiency. The influence of inducted H2 resulted in the lowest smoke opacity and HC emissions, demonstrating more complete and cleaner combustion. The results indicate at 23° bTDC of injection timing and 240 bar injection pressure produced best overall performance, with highest brake thermal efficiency and the lowest brake specific energy consumption, reflecting more efficient energy conversion and fuel use. This combination also resulted in the lowest smoke opacity, signifying cleaner combustion with minimal soot emissions. However, for emissions control, different injection timings performed better: 19° bTDC at 240 bar minimized unburnt hydrocarbon (UHC) emissions, while 21° bTDC at 240 bar yielded the lowest carbon monoxide (CO) emissions. The trade-off occurred with oxides of nitrogen (NOx) emissions, which were highest at 19° bTDC due to elevated combustion temperatures, requiring after-treatment technologies for mitigation. Overall, while 23° bTDC and 240 bar yielded the best fuel efficiency and cleanliness These settings provide a balanced approach, maximizing efficiency and minimizing harmful emissions, making them suitable for cleaner diesel engine operation.
Veeraraghavan, Sakthimurugan, Palani, Kumaran, De Poures, Melvin Victor, Madhu, S.
Towards Robust Hydrogen Combustion: Precise Lube Oil Consumption Measurement as an Enabler for Tackling Pre-Ignition2024-01-429011/5/2024
The use of carbon-free fuels, such as ammonia or hydrogen, or at least carbon neutral fuels, such as green methane or methanol is one of the most important paths in the development of low-carbon internal combustion engines (ICE). Especially for large, heavy-duty engines, this is a promising route, as replacing them with battery electric or fuel cell drives poses even greater challenges, at least for the time being. For some applications or areas of the world, small ICEs for trucks, passenger cars or off-road vehicles, operated with alternative fuels will still remain the means of choice. One of the biggest challenges in the development of hydrogen combustion engines is achieving high compression ratios and mean effective pressures due to combustion anomalies, caused by the low ignition delay and broad flammability limit of hydrogen. Oil droplets are considered to be one of the main triggers for pre-ignition and knocking. This paper will give a brief introduction, showing the results of studies on the contribution of oil droplets to combustion anomalies. In this study, oil droplets were artificially injected into the intake manifold in order to trigger pre-ignition. As the correlation between these two phenomena was clearly seen, the second part of the paper will focus on the measurement of oil consumption, which is an important way to combat combustion anomalies. To this end, three innovative measurement technologies were compared. The first method is based on the balance of carbon entering and leaving the combustion chamber. The second method is based on the use of deuterium, which is added to the engine oil as a tracer. The third method is based on measuring the unburnt portion of hydrocarbons with a time-of-flight mass spectrometer (TOF-MS). All methods provide very similar qualitative results. The deuterium and the carbon method show very good quantitative congruence as well and are therefore considered to be very precise and. The respective advantages and disadvantages are shown in the discussion chapter. Additionally, measurement data will show the influence of the hydrogen production (green vs. grey) on its isotopic ratio. This can be a measure for classifying hydrogen without knowing the exact source.
Rossegger, Bernhard, Grabner, Peter, Gschiel, Kevin, Vareka, Martin
Influence of Lube Oil and Fuel Additives on the Particulate Raw Emission Behavior of Gasoline Engines04-18-01-000410/3/2024
The aim of this work was to investigate the influence of different combinations of engine oil and oil additive as well as additivated and unadditivated fuel on particulate emissions in gasoline engines. To accomplish this, load, speed, and type of oil injection were varied on a single-cylinder engine, and the influence on particle number concentration and size distribution were evaluated. The tests were supplemented by an optical investigation of their in-cylinder soot formation. The investigation of fuel additives showed no significant differences compared to the reference fuel without additives. However, in the case of oil additives, detergents led to a significant increase in the number of particles in the <20 nm range. This effect occurred when used as both a single additive and a component in the standard engine oil. While viscosity improvers also lead to a measurable, but less pronounced, increase in the particle number concentration, no significant influence can be determined for any other oil additives. The influence of the additive is independent of the type of oil introduction by injection into the intake manifold or direct injection of a premixed oil/fuel mixture.
Böhmeke, Christian, Heinz, Lukas, Wagner, Uwe, Koch, Thomas
Performance Evaluation of Various Fractional Order Control Strategies on a Proton Exchange Membrane Fuel Cell2024-28-00949/19/2024
Proton exchange membrane (PEM) fuel cells are one potential green energy option for fuel cells, which are becoming more popular in the energy production industry. Despite the fact that it continues to draw a lot of interest, many obstacles, such as enhancing performance, boosting durability and reducing cost are impeding the fuel cells commercialization. Air/hydrogen feed has an impact on the fuel cell performance; as a result, the cathode side of the fuel cell supply manifold pressure must be regulated. Substantial power is used when operating at maximum load, and fuel cells may experience oxygen starvation due to inadequate air. Maintaining a quick and adequate air concentration in the fuel cell cathode is essential to avoiding oxygen starvation and maximizing durability. In this paper, to solve the issues of oxygen starvation in a PEM fuel cell, various fractional order control strategies are developed, and comparative analysis is done to maintain the supply manifold pressure based on error analysis and control effort. The transfer function model of a PEM fuel cell is considered and various fractional order control strategies are designed for the control of supply manifold pressure in the fuel cell. Based on simulation using MATLAB/SIMULINK software, it is observed that fractional order PID controller yields enhanced performance when compared to other fractional order controller design techniques such as fractional filter cascaded with integer order PI/PID and fractional order PI controllers.
A, Adithya, Shaik, Amjad, CHIKATI, RAMBABU
Numerical Investigation of Injection and Mixture Formation in Hydrogen Combustion Engines by Means of Different 3D-CFD Simulation Approaches2024-01-30077/2/2024
For the purpose of achieving carbon-neutrality in the mobility sector by 2050, hydrogen can play a crucial role as an alternative energy carrier, not only for direct usage in fuel cell-powered vehicles, but also for fueling internal combustion engines. This paper focuses on the numerical investigation of high-pressure hydrogen injection and the mixture formation inside a high-tumble engine with a conventional liquid fuel injector for passenger cars. Since the traditional 3D-CFD approach of simulating the inner flow of an injector requires a very high spatial and temporal resolution, the enormous computational effort, especially for full engine simulations, is a big challenge for an effective virtual development of modern engines. An alternative and more pragmatic lagrangian 3D-CFD approach offers opportunities for a significant reduction in computational effort without sacrificing reliability. The detailed and the lagrangian approach are both validated against optical measurements inside a spray chamber, provided by Robert Bosch GmbH to ensure an accurate reproduction of the injection process in the simulation. The investigation shows, that the lagrangian approach enables 30 times bigger time steps, while maintaining comparable results. The effects on jet propagation and mixture formation are examined in a virtual 3D-CFD single cylinder engine test bench under the consideration of a boosted high tumble engine concept and direct injection up to 220 bar. A variation of injection timings and the air-to-fuel ratio are carried out at two load points and validated with the test bench data. By means of the matching simulation results, it is therefore possible to explain trends in engine behavior and make detailed statements about the interaction of the hydrogen high-pressure injection and the mixture formation. Particular attention was hereby paid to the influences on gas exchange losses, NOx emissions and engine efficiency.
Schmelcher, Robin, Kulzer, Andre, Gal, Thomas, Vacca, Antonino, Chiodi, Marco
Optimization of Hydroformed Exhaust Gas Recirculation Tube under Vibrational Load by Finite Element Analysis2024-01-50626/17/2024
This study emphasizes the importance of CAE approach in optimizing EGR tube under vibrational load. EGR tube is a weak link in the EGR system and chances of failure due to vibration and relative displacement of mating parts, i.e., overhang or improper support at exhaust manifold, intake manifold, or EGR system. Consideration of the mating parts for the EGR tube is very important to get the realistic resonance frequencies, otherwise it could have some different results in the CAE, which will deviate from the reality. So, it’s important to study the dynamic response on the EGR tube, which needs to be taken care during the design phase. This paper aims to optimize the EGR tube under vibrational load by using CAE techniques and the industry experience as a product expertise. some critical parameter such as damping is very important during the CAE, which can be generated by doing the rigorous testing and how it affects the stress and correspondingly FOS. CAE model of EGR tube is created on which modal and harmonic response analysis is made. The natural frequency and stresses in the EGR tube are assessed by using CAE Tool ANSYS Mechanical. Using the CAE result observations, the changes in design of the EGR tube is done to improve its design. The design of EGR tube is improved by changing thickness, hydroformed corrugations, materials, or using different brackets. The CAE model results is also correlated with the testing results on electrodynamic shaker. EGR tube is assembled on the shaker with engine mating components having the same orientation as on vehicle. The shaker is used to find resonance frequency and to carry durability testing of the EGR tube. The results obtained from CAE model and testing are compared and found satisfactory. All the above efforts enable analysts to make the first time right design.
Munde, Ganesh, Chattaraj, Sandip, Hatkar, Chandan, Thakur, Abhishek Kumar
Guided Port Injection of Hydrogen as an Approach for Reducing Cylinder-to-Cylinder Deviations in Spark-Ignited H2 Engines – A Numerical Investigation2024-37-00086/12/2024
The reduction of anthropogenic greenhouse gas emissions and ever stricter regulations on pollutant emissions in the transport sector require research and development of new, climate-friendly propulsion concepts. The use of renewable hydrogen as a fuel for internal combustion engines promises to provide a good solution especially for commercial vehicles. For optimum efficiency of the combustion process, hydrogen-specific engine components are required, which need to be tested on the test bench and analysed in simulation studies. This paper deals with the simulation-based investigation and optimisation of fuel injection in a 6-cylinder PFI commercial vehicle engine, which has been modified for hydrogen operation starting from a natural gas engine concept. The focus of the study is on a CNG-derived manifold design which has been adapted with regard to the injector interface and is already equipped with so-called gas injection guiding tubes for targeted fuel injection in front of the intake runners of the individual cylinders. Significant deviations between the averaged cylinder pressure profiles of the individual cylinders observed on the test bench point to an issue with the equal distribution of the fuel supply to the individual cylinders. A subsequent 3D CFD simulation of the internal manifold flow showed geometry-induced turbulence of the fresh air flow in the area of the hydrogen supply outlet of several cylinders, which can lead to variations in cylinder-specific fuel quantities. In order to minimise the influence of the air flow in the manifold on the fuel injection, a dedicated injection guide concept for the gas injection tubes in the intake manifold has been designed with the aim of moving the position of hydrogen injection closer to the intake valves. In this study, this concept is analyzed based on first results obtained from a detailed 3D CFD simulation, especially in terms of the uniformity of hydrogen distribution between the cylinders, mixture formation and the effect on combustion.
Jung, Philipp Emanuel, Guenthner, Michael, Walter, Nicolas
Life Cycle Assessment of a State-of-the-Art Diesel powered Engine and Preliminary Evaluation of its Conversion into a Novel Hydrogen powered Engine2024-01-24424/9/2024
This paper is part of a broader research project aiming at studying, designing, and prototyping a hydrogen-powered internal combustion engine to achieve fast market implementation, reduced greenhouse gas emissions, and sustainable costs. The ability to provide a fast market implementation is linked to the fact that the technological solution would exploit the existing production chain of internal combustion engines. Regarding the technological point of view, the hydrogen engine will be a monofuel engine re-designed based on a diesel-powered engine. The redesign involves specific modifications to critical subsystems, including combustion systems, injection, ignition, exhaust gas recirculation, and exhaust gas aftertreatment. Notably, adaptations include the customization of the cylinder head for controlled ignition, optimization of camshaft profiles, and evaluation of the intake system. The implementation incorporates additive manufacturing for the production of new intake manifolds and a new turbocharger in order to optimize the volumetric efficiency of the new hydrogen engine. The project is targeting a wide range of applications (automotive, cogeneration, maritime, off-road, railroad, etc.). This paper focuses on the Life Cycle Assessment (LCA) of the diesel-powered engine and preliminary evaluates the effects of its conversion into a hydrogen-powered engine in terms of environmental impacts. The LCA system boundary is cradle-to-grave, and the assessment is entirely based on primary data (i.e., company-specific material and energy flows are used), which is one of the main novelties of this article. The results show that climate change, use of fossil resources, freshwater ecotoxicity, acidification, and particulate matter are the five most relevant impact categories. The diesel engine results in a carbon footprint of 0.36 kg CO2eq/km, with the use phase being the main contributor to the whole life cycle, as expected. In terms of climate change, the preliminary LCA evaluation of the hydrogen engine demonstrates that hydrogen may be a valid solution if produced from certain production routes, i.e., considering steam methane reforming and coal gasification combined with carbon capture storage systems.
Malagrinò, Gianfranco, Accardo, Antonella, Costantino, Trentalessandro, Pensato, Michele, Spessa, Ezio
The Influence of Fundamental Processing Parameters of Ultrasonic Shot Peening on Surface Characteristics of 7B50-T7751 Alloy2024-01-26814/9/2024
Aluminum alloy has become an indispensable part of the automotive industry because of its excellent mechanical properties such as lightweight, high strength, high reliability, maintainability, and low cost. Aluminum alloy is used in automobiles, such as engine blocks, cylinder heads, intake manifolds, brake components, and fuel tanks. Fatigue and fracture are the main reasons for its engineering failure. Surface strengthening techniques, such as ultrasonic shot peening (USP), are often used to improve the fatigue resistance of aluminum alloys. This article expounds on the working principle of USP and elucidates the influence of USP process parameters on the surface characteristics of aluminum alloy. Experimental results observed the effects of USP parameters on surface properties such as surface roughness, microhardness, and surface morphology. The effects of shot peening (SP) diameter, vibration amplitude of ultrasonic vibrating head, and sample placement angle on the surface state of shot-peened materials were studied. Two different shot sizes of 2 mm and 4 mm shot diameter are utilized with two specimen angles at 90° and 0°, having three vibrational amplitudes of 25 μm, 40 μm, and 60 μm for a peening duration of 5 minutes each. The experimental analysis shows that when the SP time is 5 minutes, the surface grain size is significantly refined to the nanoscale. Compared with untreated samples, the surface roughness of treated samples decreases gradually for lower surface coverage. In addition, SP can effectively improve the hardness of the material. In USP treatment, the maximum microhardness increases, and the crack growth rate decreases by increasing the SP diameter and ultrasonic vibration amplitude).
Adeel, Muhammad, Azeem, Naqash, Xue, Hongqian
A Study on Reliability-Based Maximum Service Temperature Estimation of Plastic Automotive Parts2024-01-24214/9/2024
Recently, the environmental temperature of vehicles is changing due to the electrification of vehicles and improved internal combustion engine system to reduce carbon emissions. However, mechanical properties of plastic materials change very sensitively to environmental temperature changes, and mechanical properties decrease when exposed to high temperatures. Therefore, it is important to estimate lifespan estimation of plastic parts according to temperature changes. In this paper, reliability analysis process to estimate the maximum service temperature of plastic parts was developed using aging data of material properties, environmental condition data of automotive parts, and field driving condition data. Changes in the mechanical properties of plastic materials such as glass fiber reinforced polyamide materials were tested. The environmental exposure temperature of the vehicle and parts was measured, and the general driving pattern of the vehicle was analyzed. Weibull aging model and Arrhenius physics model was applied for lifespan estimation of materials. The damage rate theory was applied to obtain the sum of damage rates in various temperature conditions since automobiles are exposed to various temperature conditions. The damage rate according to the temperature and time exposed to the environment was calculated with lifespan estimation results of materials and environment conditions of plastic parts, then the maximum service temperature that can satisfy the warranty period of the product was predicted. As case studies, the maximum service temperature of the air intake manifold, the bracket part that support the motor in EVs or the transmission in internal combustion engines with glass fiber reinforced polyamide was predicted with reliability-based maximum service temperature estimation method.
Youn, Jee Young, Chung, Min Gyun, Ahn, Hyo Sang
3-Dimentional Numerical Transient Simulation and Research on Flow Distribution Unevenness in Intake Manifold for a Turbocharged Diesel Engine2024-01-24204/9/2024
The design of engine intake system affects the intake uniformity of each cylinder of the engine, which in turn has an important impact on the engine performance, the uniform distribution of EGR exhaust gas and the combustion process of each cylinder. In this paper, the constant-pressure supercharged diesel engine intake pipe is used as the research model to study the intake air flow unevenness of the intake pipe of the supercharged diesel engine. The pressure boundary condition at the outlet of each intake manifold is set as the dynamic pressure change condition. The three-dimensional numerical simulation of the transient flow process in the intake manifold of diesel engine is simulated and analyzed by using numerical method, and the change of the Intake air flow field in the intake manifold under different working conditions during the intake overlapping period is discussed. The dynamic effects of diesel engine intake boost pressure, rotated speed, and intake pipe geometrical characteristic on the air mass flow at the outlet of each intake manifold, intake air distribution quality, and maximum intake unevenness are analyzed. According to numerical calculation result, it was obtained that the main reasons affecting the intake unevenness of each cylinder of diesel engine and the methods to reduce the intake unevenness: The lower the intake boost pressure of diesel engine, the greater the maximum intake unevenness. The greater the intake overlapping angle, the greater the maximum intake unevenness. When the diesel engine was working at low rotated speed, the maximum intake unevenness was higher than that at high rotated speed due to the long intake overlapping time. By increasing the boost pressure of the intake air, the unevenness intake air distribution of the diesel engine during the intake process could be reduced.
Yang, Shuai, Yan, Kai, Liu, Haifeng, Fu, Yahao, Liu, Hairan, Li, Tong
Analysis of Dual Fuel Hydrogen/Diesel Combustion Varying Diesel and Hydrogen Injection Parameters in a Single Cylinder Research Engine2024-01-23634/9/2024
In the perspective of a reduction of emissions and a rapid decarbonisation, especially for compression ignition engines, hydrogen plays a decisive role. The dual fuel technology is perfectly suited to the use of hydrogen, a fuel characterized by great energy potential. In fact, replacing, at the same energy content, the fossil fuel with a totally carbon free one, a significant reduction of the greenhouse gases, like carbon dioxide and total hydrocarbon, as well as of the particulate matter can be obtained. The dual fuel with indirect injection of gaseous fuel in the intake manifold, involves the problem of hydrogen autoignition. In order to avoid this difficulty, the optimal conditions for the injection of the incoming mixture into the cylinder were experimentally investigated. All combustion processes are carried out on a research engine with optical access. The engine speed has is set at 1500 rpm, while the EGR valve is deactivated. The purpose of this work is to research the minimum amount of diesel fuel, which allows efficient and controlled hydrogen ignition. Starting from the dual fuel conditions investigated in previous works with two injections per cycle, one of the diesel injections was removed. Subsequently, the shift of the start of injection and the reduction of the energizing time of the diesel injection as well as the increase in the delivered mass of hydrogen are analysed. The final aim is to obtain an indicated mean effective pressure equal to the one previously analysed avoiding backfiring phenomena in the manifolds or abnormal engine operation. All the analysed tests are in ultra lean combustion conditions with premixed ratio higher than 95% and equivalence ratio higher than 0.32. From the investigated cases, it can be found that the best combustion efficiency is determined with a diesel start of injection around 10 before top dead centre, while the lowest amount of diesel corresponds to an energizing time of the injector equal to 209μs. Regarding the hydrogen injection in the intake manifold, a dependency on the intake valve timing is highlighted. Hydrogen was prevented from being thrown into the exhaust by starting its supply after the valve crossing; on the other hand, to avoid backfiring phenomena, it is noted that the hydrogen injection has to end prior to the compression phase commences. This information is of particular interest to fulfil engine decarbonisation optimizing the use of hydrogen in compression ignition engines and facilitating CFD analysis of hydrogen combustion in ultra lean conditions.
Mancaruso, Ezio, Rossetti, Salvatore, Vaglieco, Bianca Maria
Experimental Investigation of Internal and External EGR Effects on a CNG-OME Dual-Fuel Engine2024-01-23614/9/2024
Dual-fuel engines powered by renewable fuels provide a potential solution for reducing the carbon footprint and emissions of transportation, contributing to the goal of achieving sustainable mobility. The investigation presented in the following uses a dual-fuel engine concept running on biogas (referred to as CNG in this paper) and the e-fuel polyoxymethylene dimethyl ether (OME). The current study focuses on the effects of exhaust gas rebreathing and external exhaust gas recirculation (EGR) on emissions and brake thermal efficiency (BTE). A four-cylinder heavy-duty engine converted to dual-fuel operation was used to conduct the engine tests at a load point of 1600 min-1 and 9.8 bar brake mean effective pressure (BMEP). The respective shares of high reactivity fuel (HRF, here: OME) and low reactivity fuel (LRF, here: CNG) were varied, as were the external and internal EGR rates and their combinations. CNG was injected into the intake manifold to create a homogeneous air-fuel mixture, while OME was introduced as a pilot injection directly into the combustion chamber. Results showed an increase in total hydrocarbons (THC) and carbon monoxide (CO) emissions, while nitric oxide (NOx) emissions were significantly reduced compared to diesel operation. Soot emissions were completely mitigated due to the absence of direct carbon bonds in both CNG and OME. For the initial stage of the study, exhaust gas rebreathing was implemented on only one exhaust valve through a second event lift. For the second part of the study, the second event lift was also installed on the other exhaust valve. At a substitution rate of 50 % CNG, THC emissions could be lowered by up to 35 %, CO emissions by up to 50 % and NOx emissions by up to 18 % with the use of internal EGR. The combination of internal and external EGR reduced emissions even further.
Jost, Ann-Kathrin, Guenthner, Michael, Weigel, Alexander
Sea-Level Characterization of Electrically Assisted Turbocharger for Use on Aviation Diesel Engine2024-01-19143/5/2024
Airborne compression-ignition engine operations differ significantly from those in ground vehicles, both in mission requirements and in operating conditions. Unique challenges exist in the aviation space, and electrification technologies originally developed for ground applications may be leveraged to address these considerations. One such technology, electrically assisted turbochargers (EATs), have the potential to address the following: increase the maximum system power output, directly control intake manifold air pressure, and reignite the engine at altitude conditions in the event of an engine flame-out. Sea-level experiments were carried out on a two-liter, four-cylinder compression-ignition engine with a commercial-off-the-shelf EAT that replaced the original turbocharger. The objective of these experiments was to demonstrate the technology, assess the performance, and evaluate control methods at sea level prior to altitude experimentation. This work covers the baseline characterization of the EAT as a turbocharger, on-engine EAT electrical operation for boost control, and a demonstration of system power extension capabilities. The baseline characterization quantified the aerodynamic performance of the EAT through the engine power curve. Then, the motor-generator on the EAT was used to directly control the intake manifold pressure. During this operation, the EAT recovered 2.4% of the exhaust energy as electrical power at the maximum nominal engine power condition. During the power extension demonstration, the manifold pressure and fueling was increased simultaneously to maintain a constant equivalence ratio. This resulted in a 6% increase engine mechanical power output and an increase in total system power output (electrical power plus mechanical power) of approximately 9%. Examples for potential on-aircraft configurations and recommendations for altitude experimentation are also expressed.
Pope, Aaron, Kim, Kenneth, Schroen, Erik, Clerkin, Peter, Musser, Marshall, Mattson, Jonathan, Meininger, Rik, Gibson, Joseph, Kang, Sang-Guk, Kruger, Kurt, Hepp, Kyle, Kweon, Chol-Bum
Predictive under Hood Thermal Management Model2024-26-02721/16/2024
In the automotive industry, thermal management plays a very important role to solve the problems of energy saving and emission. The under hood thermal management is one of the critical aspects in vehicle thermal management since it caters to critical aspects of engine cooling, charge air cooling, air conditioning and turbocharger cooling. The appropriate thermal management of these critical components is necessary for ensuring the appropriate performance by the vehicle. Hence, under-hood thermal management is the core of the integrated vehicle thermal management. In the thermal management analysis approaches, the numerical simulation is widely adopted as an important approach. Hence, in this paper a model is developed in MATLAB to handle 1D parametric analysis of the cooling system, while reducing the testing time and resources taken for the product development. The developed model can be used to evaluate multiple aggregate options for CAC, Radiator, Engine, Fan etc. The model predicts the Limiting Ambient Temperature (LAT), Inlet Manifold Temperature Difference (IMTD), External air flow rate, Inlet and Outlet temperatures of Air and Coolant at each aggregates using the characteristics of each aggregates (radiator, CAC, coolant pump, engine etc.) as the input. The 1D model is capable of predicting the change in performance of the cooling system with change in position of the components relative to one another. The performance of the cooling system can be predicted for different combinations of cab, radiator, charge air cooler (CAC), engine. The model can minimize the usage of resource intensive and expensive CFD and provide results in a few minutes. Moreover, the developed model has better predictive capability compared to KULI™, a 0D simulation widely used in industry. The model predictions compared fairly accurately with physical test data.
P V, Navaneeth, Prasad, Suryanarayana A N, ML, Sankar
Failure Investigation and Design Improvements for Ductile Cast Iron Multi-Piece Exhaust Manifold from Medium Duty Diesel Engine2024-26-03351/16/2024
Exhaust manifold in engine is used to transfer the hot exhaust gas from cylinder head to the turbocharger with minimum pressure loss and to support the turbocharger assembly. This puts manifold under intense thermal and mechanical loading and makes the design very complex. While designing the manifold, resonance of the system must be avoided, and thermo-mechanical fatigue life expectations must be met. Different engine applications would call for multiple turbocharger configuration and orientations to be considered in the design layout for system level resonance assessment. This paper talks about the failure investigation of the manifold which was designed for High mount rear out (HMRO) turbo orientation and then used with high mount front out (HMFO) layout in road miller application resulted into the manifold failures. Root cause identified was mechanical fatigue caused by resonance vibration at machine operating modes in the presence of very high mean stress from thermal expansion of the exhaust manifold. Detailed investigation included metallurgical analysis, vehicle level testing (strain and modal), exhaust manifold thermo-mechanical fatigue analysis, modal impact testing, thermal survey, engine endurance testing. Design improvements to the manifold included conversion from two-piece design to three-piece design. Design margin improvements in all critical region. Verification of the design and incremental benefits are demonstrated analytically and using testing.
Kale, Pradnya, Potdar, Vivek, Thakur, Anil Ganeshsingh, Paygude, Sachin
Anisotropic structural modeling of fiber-reinforced polymers used in engine peripheral components2023-36-00761/8/2024
The evolution of materials technology has provided in recent decades the replacement of the raw material of many parts made of metal by polymers, carbon fibers, ceramics, and composite materials. This process has been driven by the permanent need to reduce weight and costs, which, even after replacing raw materials, still demand permanent improvement and optimization in the sizing process and in the manufacturing process. In the automotive industry, many components have been replaced by fiber-reinforced polymers, from finishing parts to structural components that are highly mechanically stressed and often also subjected to high temperatures. Although they are lighter and have a lower final cost than conventional metallic parts, components made of fiber-reinforced polymers bring great technological challenges to the development project. Within this context, computational modeling is an indispensable ally for obtaining a product capable of meeting the severe conditions required for its service. Peripheral engine components such as air, oil and fuel filters, canisters, valve covers and intake manifolds are examples of components that are commonly made of fiber reinforced polymers, but that present relevant thermo-mechanical and vibrational requests. The simulation of the polymer injection process and its coupling to structural modeling is a crucial differential in the development of these products. The consideration of the anisotropy caused by the reinforcing fibers in the polymer has a very relevant impact in terms of stresses and strains, as well as the stiffness of these components. The fiber alignment that defines the anisotropy in the part is obtained from the simulation of the injection process and introduced in the finite element model that will be used for structural evaluation of the component. Aiming to illustrate the relevance of this anisotropic structural modeling approach, which couples the manufacturing process with structural simulation, two case studies are presented: a fuel filter subjected to rupture test comparing numerical and experimental results and the second case is the natural frequency analysis and vibration modes of a valve cover.
Bueno, Estela Mari Ricetti, Higa, Armando, Bazaneli, José Augusto
Numerical analysis of the influence of SOI and injection duration on the homogenization of hydrogen-air mixtures in a PFI SI engine under lean operation2023-36-01061/8/2024
The use of green hydrogen as a fuel for internal combustion engines is a cleaner alternative to conventional fuels for the automotive industry. Hydrogen combustion produces only water vapor and nitrogen oxides, which can be avoided with ultra-lean operation, thus, eliminating carbon emissions, from a tank-to-wheel perspective. In this context, the aim of this study is to investigate the influence of hydrogen injection timing and duration on the homogeneity of the hydrogen-air mixtures. Computational fluid dynamic (CFD) simulations were performed to analyze the distribution of air-fuel ratios along the engine's combustion chamber. The simulation software was CONVERGE 3.0, which offers the advantage of automatic mesh generation, reducing the modeling efforts to adjusting the operating conditions of the studied case. Before comparing the injection parameters, a mesh independence test was conducted along with model validation using experimental data. To properly evaluate the start of injection (SOI) angle, three points were considered, ranging from 90° before to 90° after the intake valve opening (IVO). Additionally, three values of injection duration were examined: 90°, 70° and 50° CAD, while keeping the mass flow rate of hydrogen and SOI constant. The standard deviation of the fuel-air equivalence ratio (φ) was used as a metric to compare the homogeneity of the in-cylinder hydrogen-air mixture. The results highlighted the significant impact of correctly selecting these two parameters on mixture preparation. More advanced SOI and longer injection durations resulted in a more homogeneous mixture, which can improve conditions for flame propagation and combustion efficiency. However, in cases where SOI occurred after IVO, hydrogen mass fraction gradients were higher. Moreover, depending on the injection timing and duration, the amount of hydrogen that returns to the intake manifold may increase, reducing the amount of hydrogen entering the combustion chamber, thus lowering power and increasing consumption. Therefore, the study of a hydrogen internal combustion engine in CFD proves crucial for identifying potential critical points for enhancing efficiency and improving safety during operation.
Pasa, Bruno Roberto, Fagundez, Jean Lucca Souza, Martins, Mario Eduardo Santos, Salau, Nina Paula Gonçalves, Cogo, Vitor Vielmo, Prante, Geovane Alberto Frizzo, Wittek, Karsten
Engine Operating Conditions, Fuel Property Effects, and Associated Fuel–Wall Interaction Dependencies of Stochastic Preignition2023-01-161510/31/2023
This work for the Coordinating Research Council (CRC) explores dependencies on the opportunity for fuel to impinge on internal engine surfaces (i.e., fuel–wall impingement) as a function of fuel properties and engine operating conditions and correlates these data with measurements of stochastic preignition (SPI) propensity. SPI rates are directly coupled with laser–induced florescence measurements of dye-doped fuel dilution measurements of the engine lubricant, which provides a surrogate for fuel–wall impingement. Literature suggests that SPI may have several dependencies, one being fuel–wall impingement. However, it remains unknown if fuel-wall impingement is a fundamental predictor and source of SPI or is simply a causational factor of SPI. In this study, these relationships on SPI and fuel-wall impingement are explored using 4 fuels at 8 operating conditions per fuel, for 32 total test points. The fuels were directly injected at two different injection timings: an earlier injection timing that initially targets the piston crown and a later injection timing that targets the cylinder liner. At each injection timing, the engine was operated at both 90°C and 70°C coolant and lubricant temperatures, and 185 and 200 kPa absolute intake manifold pressure. This work serves as an exploratory effort to down select conditions and provide initial fuel properties of interest for a secondary study to explore fuel property specific effects on fuel-wall interaction and SPI propensity. Significant findings from this initial operating condition and fuel property exploratory work are: 1. reduced engine operating coolant and lubricant temperatures, along with 2. retarded injection timings were required to increase SPI propensity. Moreover, at these conditions some fuel specific effects were also observed; specifically, increased ethanol content increased measured dye–wall (i.e., fuel–wall) interaction. However, despite increased dye–wall interaction, the increased volatility of the ethanol containing fuels also reduced the estimated fuel retention in the top-ring zone and associated measured SPI propensity. Thus, the findings of this unique approach to explore relationships between fuel-wall impingement and SPI highlight that SPI propensity is more directly proportional to retained fuel, and not simply fuel–wall impingement. Fuel retention was found to be directly influenced by complex fuel property and engine operating condition relationships. Either retarded injection timings and/or increased fuel volatility increased fuel wall-impingement, while less volatile fuels and/or reduced coolant temperatures increased fuel retention. Therefore, for a given operating condition, the data highlights that greater volatile fuels exhibit increased fuel wall impingement without increased fuel retention or SPI propensity, while less volatile fuels could exhibit reduced fuel-wall impingement but increased fuel retention and SPI propensity rates.
Splitter, Derek, Boronat Colomer, Vicente, Neupane, Sneha, Partridge, William
GT-Suite Modeling of Thermal Barrier Coatings in a Multi-Cylinder Turbocharged DISI Engine for Catalyst Light-Off Delay Improvement2023-01-160210/31/2023
Catalytic converters, which are commonly used for after-treatment in SI engines, exhibit poor performance at lower temperatures. This is one of the main reasons that tailpipe emissions drastically increase during cold-start periods. Thermal inertia of turbocharger casing prolongs the catalyst warm-up time. Exhaust enthalpy management becomes crucial for a turbocharged direct injection spark ignition (DISI) engine during cold-start periods to quickly heat the catalyst and minimize cold-start emissions. Thermal barrier coatings (TBCs), because of their low thermal inertia, reach higher surface temperatures faster than metal walls, thereby blocking heat transfer and saving enthalpy for the catalyst. The TBCs applied on surfaces that exchange heat with exhaust gases can increase the enthalpy available for the catalyst warm-up. A system-level transient heat transfer study using experimental or high-fidelity simulation techniques to evaluate the TBC application on various surfaces would be expensive. In this work, a reduced-order system-level modeling methodology in GT-Suite was leveraged to evaluate TBCs on exhaust ports, manifold, and runners. A multi-cylinder turbocharged DISI engine was modeled in GT-Suite, with capability to model a layer of TBC on internal surfaces. The model was calibrated using measured data from steady state operating conditions due to lack of transient cold start data. Following the TBC analysis, a theoretical study to infer the effects of turbocharger casing heat loss on the catalyst warm-up was performed. The TBCs showed no tangible benefit in the catalyst light-off delay when applied on the combustion chamber walls but showed a 20-second faster catalyst light-off when an 800-micron thick TBC was applied on the exhaust flow path walls (exhaust ports, manifold and runners). The turbocharger casing/housing heat transfer was shown to have a considerable effect on the catalyst light-off delay. An additive benefit to the catalyst light-off delay was achieved by insulating the combustion chamber walls, the exhaust flow path walls, and the turbocharger casing together which was predicted to be 25 seconds faster than the baseline.
Ravikumar, Avinash, Bhatt, Ankur, Gainey, Brian, Lawler, Benjamin
Simulation Study on EGR Condensate Flow and Uniformity of Each Cylinder in the Intake Manifold2023-01-703410/30/2023
As engine technology developed continuously, engine with both turbocharging and EGR has been researched due to its benefit on improving the engine efficiency. Nevertheless, a technical issue has raised up while utilizing both turbocharging and EGR at the same time: excess condensed water existed in intake manifold which potentially trigger misfire conditions. In order to investigate the root-cause, a CFD model (conducted by CONVERGE CFD software) was presented and studied in this paper which virtually regenerated intake manifold flow-field with EGR condensed water inside. Based on the simulated results, it concluded that different initial conditions of EGR condensed water could significantly change the amount of water which deposited in each cylinder. Thus, a coefficient of variation of deposited condensed water amount among these cylinders, was marked as the evaluation reference of cylinder misfire. Theoretically, as this coefficient of variation reduced, the EGR condensed water from intake manifold would be distributed homogeneously in each cylinder, and thus less possibility of cylinder misfire should be observed. As concluded from the presented multiple simulated results, the coefficient of variation of deposited condensed water amount was above 30% statically for the existing intake manifold, which meant the existing intake manifold had tremendous room for optimization. The result showed that the fluctuation of the inner surface of the intake manifold had a great impact on the flow of condensate water, so different surface shapes could be designed in the intake manifold to organize the flow of condensate water, so as to make the condensate water of each cylinder more uniform, and reduce the occurrence of fire.
Pan, Shiyi, Li, Guanting, Wang, Jinhua, Zhang, Nan, Xu, Zhiqin, Chen, Shanghua, Chen, Jun, Zhao, Shengwei
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