Browse Topic: Intake systems

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Influence of Eccentric Chamfer Structure at Seat Ring Bottom Hole on Swirl Ratio and Flow Coefficient in Dual-Tangential Intake Ports2026-99-05247/10/2026
The airflow characteristics of engine intake ports significantly influence combustion efficiency and emission performance. This study investigates the effects of an eccentric chamfer structure at the seat ring bottom hole on the swirl ratio and flow coefficient in a dual-tangential intake port for a four-valve diesel engine. Computational fluid dynamics (CFD) simulations and steady flow experiments were conducted under valve lifts ranging from 1 mm to 9 mm. Results indicate that the eccentric chamfer structure enhances the swirl ratio by 39 times (from 0.12 to 4.73) at low valve lifts (<6 mm) without compromising the flow coefficient. At higher lifts (>6 mm), both chamfer designs exhibit negligible differences in performance. Experimental validation confirmed the CFD results, with errors below 3% for swirl ratio and 5% for flow coefficient. This work provides a practical approach to optimize low-speed engine performance through geometric modifications.
He, Shuchao, Li, Ying, Shi, Yanfei
Experimental Investigation into Port Water Injection on the Transient Behavior of a Heavy-Duty Hydrogen Engine2026-01-07437/1/2026
Hydrogen-fuelled internal combustion engines are a potential carbon-free propulsion solution for high-power applications such as construction machinery and heavy-duty commercial vehicles. However, compared to conventional diesel engines, hydrogen engines exhibit limitations in transient operation and at full load, primarily due to the high reactivity of hydrogen. In spark-ignited hydrogen engines, combustion anomalies represent the main constraint during performance-oriented operation, particularly during transient phases that require mixture enrichment to meet dynamic torque demands. Water injection is investigated in this study as a means to mitigate these limitations. The paper describes the implementation of a port water injection system on a heavy-duty commercial hydrogen engine and evaluates its influence on engine performance with a focus on transient operating conditions. A combustion anomaly evaluation method developed in-house is applied to quantify the effect of water injection on abnormal combustion behavior. The results show that water injection shifts the combustion anomaly limit toward richer air–fuel ratios, thereby enabling mixture enrichment up to stoichiometric conditions or under during transient load changes. Water is injected cyclically into each intake port to achieve a defined water-to-hydrogen ratio during load steps. Even at low water injection rates, a significant reduction in engine response time is observed, leading to transient torque response comparable to that of a diesel reference engine. Improved torque demand tracking is demonstrated in dynamic test cycles. In steady-state operation, the application of water injection also extends the achievable full-load operating range. Overall, the results indicate that port water injection is an effective measure for suppressing abnormal combustion in heavy-duty hydrogen engines and enables more aggressive yet stable engine calibration with minimal water consumption, contributing to diesel-like performance characteristics.
Schneider, David, Christoforetti, Paul, Kappacher, Peter, Kapeller, David, Schutting, Eberhard, Eichlseder, Helmut, Trapp, Christian
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
Challenges of Mixture Formation in Methanol Port Fuel Injection Engines2026-01-03374/7/2026
Port fuel injection (PFI) is an attractive strategy for methanol adoption in both spark-ignition and dual-fuel compression-ignition engines due to its lower cost and simpler hardware compared to direct-injection. However, methanol PFI mixture formation can be challenging due to methanol’s high heat of vaporization, low volatility at cold conditions and high tendency to wall wetting. Understanding and addressing these challenges is critical to ensure robust engine operation. In this study, the effects of injector geometry, coolant temperature, intake temperature and fueling rate on mixture formation of methanol PFI have been investigated for anhydrous methanol and for a blend of 90%vol methanol plus 10%vol water in an optical engine. Mie scattering and infrared imaging were applied to assess the liquid and vapor methanol distribution in the cylinder. For a high-flow injector compatible with methanol, significant amounts of liquid were detected in the cylinder at all conditions tested, leading to poor mixing and high fuel stratification during the compression stroke. This effect was mitigated by using a multi-hole injector that promoted better atomization, indicating that high atomization is preferred over high flow for methanol PFI. The probability of detecting liquid in the cylinder decreased as the coolant temperature or the intake temperature increased or if the fueling rate decreased, with coolant temperature being the dominant parameter to control methanol vaporization. Liquid probability increased with water addition mainly because of the high heat capacity of water. Liquid methanol accumulated in the intake port, decreasing the effective engine intake temperature and limiting fuel vaporization. This accumulation led to a delay of the system response to changes in the PFI settings, with injected fuel requiring one cycle to reach the cylinder and additional 50 cycles required to completely flush the fuel accumulated in the port. Finally, the operating envelope for liquid-free operation was defined.
Lee, Sanguk, Narayanan, Abhinandhan
Analysis of In-Cylinder Flow for Hybrid Gasoline Engine using High-Speed Particle Image Velocimetry2026-01-02984/7/2026
To increase the thermal efficiency of a hybrid inline 4-cylinder direct injection engine, combustion promotion was carried out by enhancing the in-cylinder flow. The intake port and piston top shape were optimized using CFD. In-cylinder flow analysis in steady flow showed that the mean steady flow tumble ratio with the in-cylinder flow enhancement specification increased to 1.7 compared to 1.0 with the previous model and 1.4 with the early development specification. The limit engine speed, which is the engine speed at when the mean flow coefficient decreases due to the choke, and the mean steady flow tumble ratio with the in-cylinder flow enhancement specification were positioned on the trade-off line between the NA and the TC engine. In-cylinder flow analysis on the single-cylinder optical engine showed that the in-cylinder flow entering the cylinder smoothly flowed to the exhaust side, and the in-cylinder flow descending on the exhaust side was smoothly converted to the upward flow by the piston top. Thus, the tumble ratio with the in-cylinder flow enhancement specification in the latter half of the compression stroke increased from 1.0 to 1.7 compared to the early development specification. Turbulent analysis was performed by applying the time filter method, a turbulence decomposition method proposed by the authors, to the in-cylinder flow field. The turbulent kinetic energy with the in-cylinder flow enhancement specification in the latter half of the compression stroke increased by 21.9%. The flame structure was located in the corrugated flamelets region on the turbulent premixed diagram, and the combustion promotion effect by in-cylinder flow enhancement was expected. Evaluation of combustion characteristics on the metal engine showed that the initial combustion duration with the in-cylinder flow enhancement specification decreased by 2.3 deg., the main combustion duration decreased by 4.4 deg., and the time loss decreased by approximately 2%. Therefore, the indicated thermal efficiency increased from 41.9% to 42.2%, proving the concept of combustion promotion by in-cylinder flow enhancement.
Okura, Yasuhiro, Urata, Yasuhiro
Development and Preliminary Combustion Experiments of a Prototype Engine with Sleeve Valves Based on the Focusing Compression Principle2026-01-02954/7/2026
Our laboratory has proposed the focusing compression principle which employs pulsed super-multi jets of gas colliding around the chamber center. This principle aims to achieve high thermal efficiency by reducing both exhaust and cooling losses. Exhaust loss is minimized due to relatively-silent high compression. Cooling loss is reduced due to thermal insulation caused by fuel-air mixture being confined to the chamber center and the compressible flow effect. In previous studies, we conducted fundamental gasoline combustion experiments on a proof-of-concept opposed-piston engine which incorporated this principle. This engine featured eight intake nozzles in an octagonal configuration and utilized non-sinusoidal and strongly asymmetric piston movements. The results indicated the possibility of high thermal efficiency based on less knocking under high compression, and the potential for stable combustion under lean-burn conditions. As a next step towards practical application with durability, we have developed a new opposed-piston engine with a small displacement of 123 cc which maintains intake ports of octagonal configuration, featuring a unique valve system. This unique valve system is characterized by setting a cylindrical-shaped sleeve-valve in between the inner and outer- cylinders. On operation, these sleeve-valves move along the central axis of cylinders, opening or closing all eight ports on the cylinder walls simultaneously. In this paper, we first show details of the present new engine developed and its preliminary experiments including non-combustion motoring experiments, and also combustion experiments using gasoline. The engine was successfully motored up to 750 rpm with no gas leakage around the sleeve-valve at compression process. Combustion experiments were initially tested from slightly-lean conditions.
Nishizawa, Tomohiko, Naitoh, Ken, Baba, Shotaro, Ukegawa, Hiraku, Yamada, Sota, Ozono, Yuka, Abiko, Mirei, Suzuki, Yosuke, Hara, Namito, Ito, Yoshikuni, Matsubara, Kosaku, Uenoyama, Kazuyuki
Comprehensive Evaluation and Development of a Single Cylinder Engine Vehicle for Refinement of NVH Characteristics2026-26-03081/16/2026
The scale of worldwide population presents its own set of difficulties, especially in densely populated cities. Almost every individual has some form of personal transport, which leads to congestion and limited parking space. Automotive manufacturers are scaling down the size of vehicles to resolve these issues to some extent. This paper is based on the NVH development of a single cylinder diesel engine vehicle. It provides an insight into the comprehensive vehicle level NVH refinement approaches adopted. The NVH characteristics of benchmark two-cylinder diesel and baseline vehicle were measured and analyzed for target setting. The performance of each subsystem such as engine mounting, vehicle structure, intake and exhaust was evaluated, and gap analysis was performed against set targets. It was found that the engine mounting system and vehicle structure were inefficient in isolating the excitation forces. The design and location of the mounting system was evaluated using CAE and modified to improve modal performance and force isolation. The vibrations were evident at tactile locations and found to correlate with engine excitation frequency at certain locations. Hence, cradle and body structure analysis were carried out to reduce vibration transfer. Additional stiffeners and channels were added to vehicle structure which helped in eliminating problematic frequencies and noise levels. The acoustic pack of the vehicle was updated to reduce airborne transfer of noise and improve sealing of vehicle. The intake system was evaluated and the air filter with resonator size and position were modified to improve noise levels. Similarly, the exhaust muffler design was analyzed and modified to improve noise levels. Each modification was implemented and evaluated for its individual contribution in improving noise and vibration by validating on mule vehicle. After implementation of all feasible updates, the noise and vibration targets were achieved for the new vehicle.
Ghale, Guruprasad Chandrashekhar, Baviskar, Shreyas, Bendre, Parag, Kamble, Pranit, Bhangare, Amit, THAKUR, SUNIL, Kunde, Sagar, Wagh, Sachin
Comparitive Study of Hydrogen Internal Combustion Engine Performance for Port Fuel Injected and Direct Injected Technology Routes using 1D Simulation2026-26-02501/16/2026
Hydrogen Internal Combustion Engine (HICE) has the promise of zero carbon solution for the mobility industry. The key beneficiary would be the medium and heavy-duty segment of transportation which are likely to adapt the battery electric or fuel cell electric solution in longer term. This particular segment of engines need high low end torque, peak torque and rated power which cannot be compromised. Additionally, a competitive thermal efficiency w.r.t diesel engines would be advantageous. Direct Injection (DI) of hydrogen gives higher specific power and thermal efficiency as compared to Port Fuel Injection (PFI). This study focuses on the performance characteristics of these technology routes to aid in the HICE development process. Current work involves the use of 1-D thermodynamic simulation using GT-SUITE for modeling the performance of HICE. Both predictive and non-predictive methodologies of modeling the combustion were employed. Initially, the model validation of the PFI engine model was carried out with the HICE baseline experimental data for a heavy-duty commercial truck engine. Subsequently, a DI engine model was created and with similar combustion modeling methodology, the performance assessment was carried out. The study presents all aspects of full throttle performance of both the PFI and DI technology routes for HICE. The simulation results show that DI methodology is advantageous as it gives a minimum of 3 to 5% increased torque as compared to PFI route with the same turbocharging system. Using a DI methodology helps to enhance the volumetric efficiency of the engine unlike PFI where the hydrogen gas displaces air in the intake system. DI strategy is also less susceptible to knocking combustion. Various combustion behavior insights namely, the combustion duration, mass burned fraction, peak combustion pressures and temperatures are also obtained as a part of the study.
Parthiban R, Varun, Karthikeyan, K R, Narayana Reddy, J, Paramasivam, Prakash, Manjunath, M, Kumar D, Kishore, N R, Varatharaj, Suresh, K, G, Yogesh Bolar, Sadagopan, Krishnan, Pandey, Sunil Kumar
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
A Strategic Approach to Design Automotive Intake Systems for Achieving a Sporty Acoustic Signature at the Drivers Ear Level2026-26-03281/16/2026
In pursuit of a distinct sporty interior sound character, the present study explores an innovative strategy for designing intake systems in passenger vehicles. While most existing literature primarily emphasizes exhaust system tuning for enhancing vehicle sound quality, the current work shifts the focus toward the intake system’s critical role in shaping the perceived acoustic signature within the vehicle cabin. In this research work, target cascading and settings were derived through a combination of benchmark and structured subjective evaluation study and aligning with literature review. Quantitative targets for intake orifice noise was defined to achieve the desired sporty character inside cabin. Intake orifice targets were engineered based on signature and sound quality parameter required at cabin. Systems were designed by using advanced NVH techniques, Specific identified acoustic orders were enhanced in the intake system to reinforce the required signature in acceleration as well as in cruising mode. A novel decomposition method was developed to identify exact contribution of intake system’s noise from overall in cab noise. Based on advanced NVH analysis and sound diagnosis a precise identification of intake system contributions during both acceleration and cruising conditions was carried out. Furthermore, sound design strategy was developed which targets a dual-mode acoustic profile. The developed design strategy was validated at vehicle level, confirming that the intake system design met both subjective and objective targets. This integrated approach provides a repeatable framework for intake sound design, offering OEMs a robust pathway to differentiate sporty vehicle character through intelligent intake acoustics. This work not only demonstrates the critical role of intake design in vehicle sound signature development but also proposes a systematic methodology for future vehicle sound engineering.
Sadekar, Umesh Audumbar, Titave, Uttam, Patil, Jitendra, Naidu, Sudhakara
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
Mitigating Air Flow Sensor Signal Variability to Optimize Engine Operation in Passenger Cars2026-26-05121/16/2026
In order to control the engine performance which is driven by the strict emission regulations and customer request for the improved fuel economy, precise air intake measurement and fuel control system are essential. In the modern engines, the mass air flow sensor (MAF) acts an important role which provides a precise estimation of air flow from the clean side ducting of air intake system to engine control unit module (ECU). The hot wire mass air flow sensor are mounted on the clean side of the air intake system in order to protect the sensing element from the contamination and to extend their lifespan as well as maintain its accuracy. It is essential to maintain a steady and a uniform airflow at the sensing element of the MAF sensor for reliable sensor reading at different engine speeds and varying engine load. However, the physical limitations of engine packaging inside the engine bay, limits the sensor placement. Incorrect sensor mounting can lead to errors in the airflow estimation which in turn adversely affect engine thermal performance and emissions. During the development of a new passenger vehicle, it was observed that the unpredicted engine torque oscillations were detected and that too in various operating conditions. When the root cause of these oscillation were studied, it was linked with the oscillations and fluctuations in the MAF sensor’s output signal. In order to address the issue, a number of clean side ducting as well as air filter assembly top cap geometry and configuration were modified and studied. These design iterations were tested on the dynamometer in order to identify their effect on the sensor signal and corresponding engine torque variation. The current paper presents the investigation and evaluation of the different clean side ducts geometries and sensor mounting strategies. This would ensure that there will be minimum signal disturbance which would further improve the mass air flow measurement accuracy. The final air intake clean side design have reduced sensor signal pulsations and oscillations significantly. This has further lead to a smoother and more stable engine torque output.
Sonone, Sagar Dinesh, Zope, Mahesh, Kale, Vishal, Padmawar, Harshad, Sridhar, S, Kolhe, Vivek M, Panwar, Anupam
Engine Compartment Front End Module & Snorkel Placements to Achieve Maximum Volumetric Efficiency2026-26-05881/16/2026
The rising demand for electric vehicles (EVs) has pushed automakers to prioritize visual brand consistency across both EVs and internal combustion engine (ICE) vehicles. A main design factor which is influenced by this trend is the front grille. In order to achieve uniform aesthetic looks, passenger car manufacturers often reduce the front grille openings and limit airflow. This closed grille style is common in electric vehicle. However, this creates challenges for internal combustion engine (ICE) vehicles with snorkel-type air intake systems, leading to reduced airflow and higher temperatures in the engine bay and intake air which eventually gets sucked in the engine resulting in low volumetric efficiency. Maintaining a cooler intake air is vital for ICE performance. Adjusting snorkel position and airflow patterns in low temperature zones ensures the engine receives air at low temperatures. This improves the combustion efficiency, throttle response and eventually it reduces the risk of knock. This study emphasizes the need to control intake air temperature in such a way that the air intake system supports to meet performance and emissions targets. In our study, we use simulation tools such as computation fluid dynamics (CFD) and experiments in order to demonstrate that the ICE vehicle grille design having restricted air flow which are similar to the electric vehicles, increases the air temperature that enters into the snorkel of air intake system. This pre-heated air that enters into engine reduces its efficiency, power output and also might eventually affect the emissions. The findings in our study quantifies the thermal penalty that are linked to this design standardization. In order to overcome these issues, the study recommends tailored front-end module thermal management strategies for ICE vehicles particularly for air intake system. The approach optimizes airflow and minimizes heat gain in snorkel of air intakes and hence preserving engine performance without sacrificing the visual consistency between EV and ICE models.
Sonone, Sagar Dinesh, Singh, Nil Kanth, Kolhe, Vivek M, Kulkarni, Chaitanya, Malekar, Hemant A
Accelerating Engine Auxiliaries’ Development by Deploying ML Techniques in CFD Virtual Verification2026-26-03741/16/2026
The automotive and off-road industries are heavily investing in R&D to improve both physical and virtual verification and validation techniques. Recent software and hardware advancements have extended these techniques from simple component evaluations to complex system assessments such as involving multi-physics scenarios. Despite the benefits of virtual validation tools like structural analysis and CFD, they often come with high development costs, particularly in CFD applications. Virtual verification methodology, especially when combined with data science, offer significant advantages over traditional physical methods by enhancing CAE efficiency and reducing resource consumption which can greatly improve product design and validation efficiency across many industries. The success of machine learning applications depends on effective data processing, adequate computational resources, and the right algorithm selection. Key machine learning techniques impacting the CFD field include data analytics, PBML reduced-order models, geometry deep learning, and physics-informed neural networks (PINN). This study explores the application of Machine Learning (ML) in the Computational Fluid Dynamics (CFD) domain, specifically targeting exhaust-driven aspiration and aftertreatment systems. By leveraging numerical data-driven techniques such as data analytics and Parametric-Based Machine Learning (PBML), the research demonstrates how ML can effectively predict quantitative outcomes based on parametric input variables. A key focus is placed on the importance of selecting appropriate regression models, as different techniques significantly influence the quality of design decisions. The study evaluates multiple regression approaches to identify optimal solutions for predicting system performance metrics. The proposed PBML framework offers a scalable and efficient alternative to traditional CFD methods, particularly in applications where outcomes are heavily dependent on design and simulation parameters—such as intake systems, tailpipe configurations, and cooling systems. By reducing computational demands and accelerating analysis, this approach supports faster and more informed decision-making in early-stage design processes.
Jadhav, Mitali, Kumbhar, Appaso, Tirumala, Bhaskar, Nisha, Kumari
DPF Passive Regeneration Approach for CEV/TREM-V Off-Highway Applications2026-26-02111/16/2026
With introduction of Diesel Particulate Filter to achieve CEV/TREM V Emission Limits for off-highway segment, there is a requirement of DPF regeneration at defined intervals depending on time of operation and soot loading in DPF. This can be achieved by two methods. First is the frequent regeneration or Active regeneration, wherein fuel is injected before DOC (Diesel Oxidation Catalyst) at specific temperature to burn the soot in the DPF. The second method is the continuous or Passive regeneration, where soot is burnt based on NO2. DPF frequent regeneration (Active Regeneration) requires soot load estimation in DPF over entire engine operation range as well as vehicle operation in different climatic conditions. Frequent regeneration leads to oil dilution and penalty in the fuel consumption. More frequent regeneration promotes the chemical aging of DOC, leading to the poor performance of DOC which results in deteriorating performance of SCR(Selective Catalytic Reduction) situated downstream of DPF. In addition to Passive Regeneration Approach, modelled air path is used as complexity of using Mass Flow Sensors lies with robust calibration of air system model considering different vehicle variants/change in layout in real world & owing to dust contamination in Off-Road Vehicles. To avoid the shortcomings of the frequent regeneration in off-road application, the DPF regeneration was achieved by Passive regeneration approach. In this paper, continuous Passive regeneration will be discussed in detail for CEV/TREM V Legislation.
Sharma, Rakshit, Garg, Varun, Dhiman, Nitish, Grauenfels, Attila
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
Calibration Strategies to Overcome the Challenges for Naturally Aspirated Off-Highway Engines for TREM V Emissions2026-26-02101/16/2026
The transition to TREM V emission norms presents significant challenges for naturally aspirated (NA) off-highway engines. Off-highway applications like construction and agriculture segments require high load variability and extended duty cycles with increased BMEP resulting in high PM emissions, and increased exhaust temperatures with lower lambda levels. Given the cost-competitive nature of the segment, it also requires designing leaner intake and exhaust system. To overcome above mentioned challenges, holistic calibration strategies need to be adapted during development phase. To meet TREM V emission norms, solutions like advanced combustion, high-pressure fuel injection, EGR (exhaust gas recirculation), and optimized calibration had to be explored along with aftertreatment systems like Diesel Particulate Filters and Diesel oxidation catalysts. Implementation of aftertreatment systems for TREM V pre-dominantly with naturally aspirated engines will result in challenges associated to soot accumulation and thermal management. This paper attempts to examine, the key technical challenges coming from the market towards use of large implements and heavy soil with NA engine demanding high BMEP, and challenges associated to aftertreatment system due to low operating lambda, smoke emissions and high exhaust gas temperature under different use cases. The research identifies the strategies, such as optimized air-fuel management, optimal specific soot load adaptation and multistage thermal control, to enhance system safety and reliability. Ultimately, the paper provides a strategic roadmap for industry stakeholders to achieve TREM V emissions while ensuring durability, efficiency, and economic viability in off-highway applications.
Patil, Madhavi M., Ravukutam Sr, Aniketh, Raghu, M Y, Madhukar, Prahlad
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
Visualization of Ammonia Engine by Pre-Chamber Igniter2025-01-053011/25/2025
Ammonia is considered more and more as a promising carbon-free fuel for internal combustion engines to contribute to the decarbonization of several sectors where replacing conventional engines with batteries or fuel cells remains unsuitable. However, ammonia properties can induce some challenges for efficient and stable combustion. This study investigates the use of an active pre-chamber ignition system fueled with hydrogen and compares it to conventional spark ignition, with a focus on lean limit operation and early flame development. Experiments were conducted on a single cylinder optical engine with a compression ratio of 9.5, equipped with a quartz window in the piston for natural flame luminosity imaging using a high-speed camera. The engine was fueled with a mixture of 95% ammonia and 5% hydrogen by volume. Ammonia was injected and mixed with air in the intake port while hydrogen was directly injected into the prechamber. As a function of the intake pressure (1.0, 0.9, 0.8, and 0.7 bar), the lean operating limit was determined as 0.7, 0.8, 0.85, 0.9 for both active pre-chamber and spark ignition strategies. In fact, with hydrogen prechamber ignition, significant faster combustion was achieved which reduced by 30% the overall combustion duration. The visualization of natural emission of flame revealed a more distributed and faster flame propagation with the active prechamber, indicating a higher ignition performance and faster combustion under lean ammonia-hydrogen conditions, highlighting its potential for extending operating limits and improving combustion robustness.
Rousselle, Christine Mounaim, Brequigny, Pierre, Gelé, Raphaël, Moreau, Bruno
Sustainable Engines with Carbon-Neutral Fuels – Fast Adaptation for Efficient Multi-Fuel Operation by Tailored Charge Motion Design2025-01-053411/25/2025
As a fundamental element of measures to reduce the carbon footprint of commercial applications, carbon-neutral fuels are increasingly coming into focus for heavy installations. In addition to diesel substitute fuels, alternative energy carriers like NG, H2, MeOH and NH3 are gaining increasing attention. The energy conversion of these fuels is typically taking place on the principle of premixed combustion, which places different demands on fuel injection and mixture formation, as compared to optimized diesel-like combustion. Accordingly, the demand to layout multi-fuel capable engine designs centers to a high share on the above-mentioned design that can burn these different fuels with high efficiency and support a high degree of commonality with the in-series engine to carry over reliable operation and to maintain attractive cost figures. FEV has developed the Charge Motion Design (CMD) process, which can be applied to design the intake ports and combustion chambers for multi-fuel cylinder heads in the initial phase. This advanced methodology features the capabilities to predict the performance of different configurations for the various fuels based on condensed and simplified CFD simulations and dedicated post-processing routines. These correlations are tuned and calibrated to representative engine data for individual fuels to determine the characteristics. This paper highlights the detailed application of the CMD process for cylinder head and combustion chamber definition on the base of measurements on a state-of-the-art modular single-cylinder HD engine. Six configurations of the port designs and charge motion concepts were investigated. A comparison of the concepts was first performed with the CMD fuel correlations for H2. Three concepts with varying degrees of tumble were chosen for further detailing. The results of the case study are presented along with supporting engine measurements. In addition to previously tuned correlations, new measurements with NH3 were used to calibrate and synchronize the correlations of the CMD process. A dedicated variant of the DI H2 injection in addition to the ammonia port injection was investigated as well. The CMD fuel correlations were correlated to the testing data and later applied to all configurations to evaluate their performance and suitability. This technical study highlights the potential of CMD-driven design to enable flexible, efficient, and cost-effective multi-fuel combustion.
Koerfer, Thomas, Dhongde, Avnish, Boberic, Aleksandar, Zimmer, Pascal, Pischinger, Stefan
Effect of EGR and Ethanol additive on Performance and Emission Characteristics of Diesel Engine Fuelled with Rubber Seed Biodiesel Blends2025-28-022411/6/2025
Alcohol is being considered as an alternative to traditional fuels for compression ignition engines due to their oxygen content and biomass origin. Although alcohol generally has lower cetane numbers, which makes them more favorable for premixed combustion, they also offer potential for lowering emissions in internal combustion engines, particularly when combined with strategies such as exhaust gas recirculation (EGR). This research focuses on enhancing the performance of a single-cylinder, four- stroke diesel engine by introducing ethanol into the intake port during the intake phase. Diesel and rubber seed biodiesel were used as primary fuels and were directly injected into the combustion chamber. The findings indicated that adding ethanol to rubber seed biodiesel, along with 10% EGR, led to improved brake thermal efficiency and a reduction in NOX emissions. The ethanol injection timing and duration were optimized for effective dual-fuel operation. At full engine load, the highest brake thermal efficiency recorded with a 20% ethanol energy share was 34% for diesel, 31.16% for B20 with EGR, and 31.15% for B20 without EGR. Furthermore, NOX emissions were reduced by 25.44% and 26.08% for B10 with EGR and B20 with EGR, respectively, at peak thermal efficiency. On the downside, increasing ethanol contribution raised HC, CO₂, and smoke emissions across all loads for both B10 and B20 with EGR. Additionally, B10 and B20 with EGR experienced higher peak cylinder pressures and maximum rate of pressure rise, while ethanol uses also resulted in shorter combustion duration and increased heat release rates.
Saminathan, Sathiskumar, G, Manikandan, Bungag, Joel Quendangan, T, Karthi
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
Measurement of the Liquid Fuel Film on the Combustion Chamber Wall of a Gasoline Engine using a Novel Capacitive Sensor2025-32-001811/3/2025
The reduction of exhaust emissions and particulate matter from internal combustion engines remains a critical challenge, particularly under cold start and warm-up conditions, where a significant portion of total emissions is generated. In spark-ignition (SI) gasoline engines, the formation of liquid fuel films on intake ports wall, piston and cylinder wall surface significantly contributes to unburned hydrocarbon and particulate emissions. Also, the fuel film adhering to the wall can be a cause of the lubricating oil dilution. To address these issues, a novel capacitive sensor, fabricated using MEMS technology, was developed and applied to investigate the behavior of liquid fuel films formed inside the combustion chamber of a single-cylinder engine. The sensor detects changes in capacitance caused by fuel film adhesion to the sensor surface. The sensor was installed in a single-cylinder test engine along with a direct fuel injector allowing for the controlled formation of fuel films on the sensor surface. Ethanol was used as the injected fuel for film formation due to its higher permittivity compared to iso-octane, the fuel used for engine operation. This choice enhanced the sensor sensitivity to film presence. Four experimental configurations were tested, varying the sensor’s location (intake vs. exhaust side) and whether the ethanol spray directly impinged on the sensor. The engine was operated at 2000 rpm with an intake pressure of 90 kPa. The coolant temperature was varied from 20 °C to 80 °C to simulate cold start and warm-up conditions. The transition from motoring to firing operation was used to replicate transient startup behavior, and the sensor output was monitored cycle-by-cycle. Results showed that the sensor effectively captured the formation and evaporation of the fuel film. Sensor output was significantly higher at locations exposed to direct ethanol spray, particularly at lower coolant temperatures, indicating greater film accumulation. Conversely, positions shielded from the spray exhibited minimal signal variation. Additionally, sensors mounted on the exhaust side showed faster recovery to baseline values, attributed to higher wall temperatures promoting quicker evaporation. In conclusion, the developed capacitive sensor demonstrated high sensitivity and reliability in detecting in-cylinder fuel films under realistic engine conditions. Its compact design and ease of integration make it a promising diagnostic tool for studying fuel film dynamics in production engines.
Kuboyama, Tatsuya, Nakajima, Takeru, Moriyoshi, Yasuo, Takayama, Satoshi, Nakabeppu, Osamu
Investigating the Influence of Intake Runner Configuration on Scavenging and Combustion Processes in Elliptical Rotor Engines2025-32-008911/3/2025
Elliptical rotor engines (ERE), also known as X-engines, feature intake and exhaust ports located on the rotating rotor. As the rotor turns, these ports traverse the entire combustion chamber, sequentially completing the scavenging process in three distinct combustion chambers through coordination with the cylinder walls. This intake and exhaust characteristic significantly differs from the characteristic found in traditional Wankel rotor engines. This study established an optical elliptical rotor engine to obtain the in-cylinder flow field by using Particle Image Velocimetry (PIV) and constructed a CFD model based on the experimental results. Then the effects of two different intake runners on the scavenging and combustion process of ERE were investigated. The results indicated that: Due to structural limitations, the prolonged intake port opening duration results in significant gas backflow during the intake process. The curved intake runner exhibits a higher turbulent kinetic energy (TKE), while the straight intake runner achieves faster intake velocity. At engine speeds of 3000 r/min, 5000 r/min, and 9000 r/min, the straight intake runner improved volumetric efficiency by 2.6%, 4.6%, and 22.8% compared to the curved intake. At low speed, the curved intake runner demonstrates superior maximum cylinder pressure and combustion performance due to its faster flame propagation speed. However, at high engine speed, the influence of intake runner on the in-cylinder flow field diminishes. The straight intake runner’s higher volumetric efficiency compensates for its slower flame propagation speed, resulting in better cylinder pressure and combustion parameters compared to the curved intake runner.
Qin, Jing, Wang, Yingbo, Pei, Yiqiang, Yao, Dasuo, Deng, Xiwen
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
Development of the Hydrogen Fueled Internal Combustion Engine for Off-Road Applications2025-32-006611/3/2025
This paper focuses on the potential application of hydrogen fueled internal combustion engine (HICE) in the off-road market, examining HICE based on a diesel engine. In the transition to HICE, priority was given to compatibility with existing systems, minimizing changes from the base engine. By adopting a PFI (Port Fuel Injection) method for fuel injection, low-pressure hydrogen supply was achieved. To address the issue of backfire associated with PFI, optimization of injection pressure using a variable pressure control valve, along with adjustments to valve timing and injection timing, was implemented to suppress backflow of residual gases into the intake system and minimize hydrogen retention. Regarding pre-ignition, in addition to suppressing hotspots, the relationship between the homogenization of the air-fuel mixture and NOx emissions was examined, revealing a correlation. This engine was mounted on a generator, and efforts were made to improve the important characteristic of responsiveness in generators. As a result, it was confirmed that the responsiveness is comparable to that of existing gas engine generators.
Shiraishi, Kentaro, Kishi, Shinji, Kato, Daichi, Mitamura, Kenta, Murakami, Kei, Mikuni, Yusuke
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
Simulation of Swirl and Discharge Coefficient Trade-off for Diesel Engine Intake Ports2025-24-00079/7/2025
In Diesel engines, charge motion usually consists of swirl and squish flow patterns. Traditionally, swirl generation is controlled through the design of the intake ports, presenting a trade-off between swirl and mass flow rate. An alternative approach to generate swirl is to use vortex-generating jets in the intake port. As a comparative basis for this approach a Pareto front was established between swirl and mass flow rate based solely on geometric variations. A new fully parametric geometry was deployed, with two intake ports per cylinder adhering to some constraints. Stationary flow-bench test setup was modeled, where a blower draws air through the intake ports at a constant pressure difference. The Pareto front was generated using semi-randomly selected geometries in combination with automated unsteady RANS (URANS) simulations, while scale adaptive simulations (SAS) were also employed on select geometries. These turbulence modeling approaches were explored using the OpenFOAM framework and it was found that URANS results exhibited relatively high volatility between similar geometries compared to SAS and showed significant dependence on grid size and quality. While the automated URANS runs showed these uncertainties, they were sufficient to create a robust Pareto front for general applications, as validated by experiments at the flow-bench.
Kahraman, Ali Berk, Ritter, Johann, Eilts, Peter, Scholz, Peter
Achieving Enhanced Swirl with Vortex Generating Jets in a Light-Duty Direct-Injected Diesel Engine2025-24-00169/7/2025
As the transportation sector faces increasingly stringent environmental regulations, enhancing thermal efficiency and reducing emissions remain critical objectives. The development covers combustion process, lubrication to exhaust gas after treatment as well as engine control strategies. This study focuses on both charge exchange and combustion processes. Swirl plays a crucial role in combustion and engine performance. Conventionally, swirl is induced through intake port geometries such as helical and tangential designs, though these methods compromise airflow, leading to increased pumping losses. In this context, our study builds on earlier work from our institutes, employing Vortex Generating Jets (VGJs) to produce swirl. VGJ are a state-of-the-art technology in the aerospace industry to increase capability of aircraft by influencing airflow. Three representative intake ports were selected from a computational fluid dynamics (CFD) simulated Pareto front - characterizing high, mid, and low swirl scenarios - for empirical evaluation. These simulations follow the geometric constraints of a passenger car 2L diesel engine. The influence of air injection via VGJs into the intake ports was investigated using a steady-state flow test bench, assessing impacts on swirl and flow. A variation in VGJ placement and injected airflow rates revealed that strategic air injection significantly enhances both swirl and flow. The increase in swirl by air injection via VGJ rises with lower base swirl of the geometry. Notably, the low swirl / high flow scenario achieved a substantial increase in swirl levels comparable to the high swirl case, without compromising airflow, thereby demonstrating the potential to surpass the existing Pareto front through swirl generation using VGJs and suggests a new achievable limit. With air injection the discharge coefficient can be increased by 26 % while maintaining the same swirl level with a different port geometry.
Ritter, Johann, Kahraman, Ali Berk, Wenz, Erich, Scholz, Peter, Eilts, Peter
Parametric Analysis of Performance and Efficiency of Free-Piston Linear Generators with 1D and CFD Simulations2025-24-01059/7/2025
High efficiency, fuel flexibility, and seamless integration with electrified systems are fundamental prerequisites for the next generation of internal combustion engines. In this context, the free-piston linear generator (FPLG) evolves the traditional internal combustion engine concept (ICE) by replacing the crankshaft mechanism with a linear generator, directly converting piston motion into electricity. The FPLG offers several advantages, including higher efficiency in converting mechanical energy to electricity, the ability to operate with a variable compression ratio, and reduced heat losses during the expansion stroke. Among the various tested architectures, the two-stroke, opposed-piston FPLG appears to be the most promising. However, detailed numerical and experimental investigations are necessary to fully understand how performance and efficiency are influenced by the intricate interplay of processes governing electricity generation. In particular, the significant differences between conventional crankshaft-based engines and FPLG kinematics have a profound impact on gas exchange and combustion processes. This study presents a numerical analysis of the key parameters affecting the performance and efficiency of spark-ignition opposed-piston FPLGs. Simulations were conducted using a modified 1D code, which accounts for the effects of electrical load and gas spring pressure on piston motion. Given the unconventional geometry featuring uni-flow scavenging and a side-mounted spark plug, preliminary CFD simulations were performed to develop realistic intake and exhaust system schematics and to establish an appropriate heat release rate profile. Methane was chosen as the fuel for two main reasons: it can be produced from biogenic sources and is applicable to both mobility and power generation. Additionally, its high octane number makes it particularly suitable for FPLG operation at high compression ratios. A single-cylinder unit (~250 cm3) was simulated as an initial step toward developing a small-scale prototype. Simulations examined the effects of gas spring pressure, charging pressure, electrical load, and spark timing. The results indicate that efficiency is maximized by applying the highest possible load under given operating conditions and introducing backpressure on the exhaust side to improve trapping efficiency.
Morandi, Nicola, Lucchini, Tommaso, Gianetti, Giovanni, Baratta, Mirko, Misul, Daniela, Santonocito, Fabrizio
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
Development of a Euro VII-Compliant Diesel Combustion System for Light Commercial Vehicles2025-24-00359/7/2025
Recent European regulations introduced in the transportation sector have increased stringency on tailpipe CO2 and regulated emissions, starting from 2025. The development of advanced technologies and the utilization of alternative fuels for internal combustion engines play a key role in the short- to mid- term in complying with such regulations and supporting sustainable transition of the transportation sector. In this study, the focus has been to develop an advanced Diesel combustion system for light commercial vehicles application in compliance with the latest Euro VII regulations and with the primary aim to improve fuel economy. The adopted methodology began with the virtual development and optimization of the entire combustion system encompassing bowl shapes, injector nozzles, and intake port specifications, leveraging a Machine Learning approach based on high-fidelity 3D CFD combustion models. Two virtually optimized combustion system “recipes” have been identified and then experimentally investigated to fine-tune the nozzle specifications, injection strategies and charge motion by means of Design of Experiments approach. The results have been compared with the baseline combustion system in terms of performance, efficiency, criteria pollutants, and combustion metrics. The recorded improvements have been notable, with a combined reduction of Brake Specific Fuel Consumption (BSFC) up to ~4% and soot emissions in excess of 90% compared to the baseline (at same level of NOx), enabling in turn a significant rematching of engine out NOx emissions in the spirit of Euro VII stringency.
Belgiorno, Giacomo, Malagrinò, Gianfranco, Pezza, Vincenzo, Spedicato, Tonio, Storsillo, Vito, Gallone, Alessandro, Alletto, Massimiliano, Pesce, Francesco, Vassallo, Alberto, Colombo, Giovanni, Formica, Angelo, Lerda, Francesco, Mirzaeian, Mohsen, Vitiello, Michele
Water Injection as an Enabling Technology for Stoichiometric High Performance Normally Aspirated Engines2025-24-00279/7/2025
The mainstream automotive market is rapidly transitioning to electrified and fully electric powertrains. Where gasoline engines are still employed, they are frequently turbocharged units with relatively low maximum engine speed and modest power density. The hypercar class, in contrast, has recently seen somewhat of a renaissance in high performance, high speed, naturally aspirated gasoline engines, which are prized for their emotional contribution to the vehicle. In order to guarantee high conversion efficiency of a Three Way Catalyst in the exhaust system, an engine must be operated at stoichiometric air-fuel ratio. At high power density, this may result in very high exhaust gas temperature, which poses a risk to engine and vehicle hardware. A number of technological interventions to extend the maximum stoichiometric performance whilst respecting component limitations have already been described in the literature, but many of these are not applicable to specific engine architectures in the hypercar niche. This work describes some of the unique challenges for such vehicle types in achieving stoichiometric operation in all conditions and identifies water injection as a key enabling technology. An experimental campaign on a high speed normally aspirated mule engine with water injectors installed in the intake ports is described. This is supported by Computational Fluid Dynamics calculations with detailed chemistry and bench testing of the injectors using Phase Doppler Anemometry and momentum flux techniques. It is shown that stoichiometry can be maintained at peak power, but some further complementary technologies may be of interest to limit water consumption and ensure an adequate combustion stability.
Corrigan, Dáire James, Villa, Davide, Penazzi, Eugenio, Meghani, Amit, Knop, Vincent, Caroli, Giacomo, Frigeri, Davide, Ruggiero, Federico, Malaguti, Simone, Postrioti, Lucio, Maka, Cristian
Hydrogen Crankcase Slip Phenomena: Experimental Study of Forced Ventilation Effects on Hydrogen Engine Performance and Emissions03-18-05-00338/22/2025
Hydrogen internal combustion engines (H2 ICE) are showing impressive potential to replace fossil fuel–based ICE platforms with zero-carbon engine-out emissions. However, adopting 100% hydrogen has its challenges due to its unique properties, such as the rapid flame velocity, the minimum igniting energy, and the lowest density. These unique properties of hydrogen impose an increased risk of ignition and combustion of hydrogen in the engine system due to leakage or inadequate ventilation. One of such scenarios is the hydrogen gas in the crankcase as a result of hydrogen slip through the piston rings. In this study, an experimental investigation was conducted on a single-cylinder hydrogen direct injection spark ignition engine, which was originally designed for boosted DI gasoline engine operation. A crankcase-forced ventilation system was designed and adopted with a hydrogen sensor in the closed feedback loop. The hydrogen concentrations in the exhaust gases and crankcase were measured simultaneously by two V&F hydrogen analyzers to assess the total hydrogen slip phenomenon. In particular, the impact of the intake boost and forced ventilation system on hydrogen slip and engine performance was investigated by varying the relative air-to-fuel ratio (lambda) and forced crankcase flow rate, respectively. The study reveals that the hydrogen slip was significantly increased by adopting lean-burn combustion at high-load operations. The results show that the hydrogen slip in the crankcase can be as high as 100,000 ppm with only the natural crankcase ventilation. Forced crankcase ventilation has been shown to be an effective method to avoid hydrogen accumulation in the crankcase and to drop the hydrogen slip in the crankcase by more than 86%. Additionally, the indicated thermal efficiency can be increased by 1.24% by fully recovering the hydrogen into the intake system through the forced ventilation system.
Mohamed, Mohamed Ali, Wang, Xinyan, Zhao, Hua
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
Development of Combustion System for a Hybrid-Dedicated Homogeneous Lean Burn Engine2025-01-02166/16/2025
This study explores strategies to extend the lean combustion limit, improve thermal efficiency, and reduce engine-out emissions in a hybrid-dedicated homogeneous lean-burn engine. Under lean combustion conditions, slow laminar flame speed hinders flame kernel growth, leading to combustion instability and limiting lean limit of air excess ratio. To address this challenge, the combustion system is developed to generate high-intensity in-cylinder flow promoting plasma channel expansion at the spark plug gap and enabling the formation of larger initial flame kernel. A newly designed intake port and piston bowl geometry were introduced to enhance tumble flow, significantly raising convective flow speed at the spark plug gap. This accelerated the initial combustion process and effectively expanded the lean combustion limit. A high-energy multiple ignition was also implemented to prevent spark channel blow-off or short circuit caused by increased electrical resistance, further improving combustion stability under lean operation. Additionally, new spray pattern was developed to enhance mixture homogeneity and robustness, thereby reducing HC and NOx emissions. An electric supercharger was integrated to precisely manage air dilution and to provide a sufficient boost for powering a D-segment SUV when combined with hybrid electric motors. The synergy of these technologies enabled stable combustion at air excess ratio exceeding λ=2.0, achieving the maximum peak thermal efficiency of 45% and NOx emissions below 0.3 g/kWh at 2000 rpm and 8.5 bar. This study highlights the impact of each technology on combustion characteristics and underscores the potential of lean-burn engines as a viable solution for meeting stringent future emission regulations with significant carbon reduction.
Oh, Heechang, Lee, Jonghyeok, Sim, Kiseon, Park, Jongil, Kim, Taekyun, Kang, Hyunjin, Hong, Seungwoo, Han, Donghee, Kim, Dokyun
Decarbonisation of GDI Engines Utilising On-Board Hydrogen Production in an Improved Design Thermochemical Exhaust-Assisted Fuel Reformer2025-01-01866/16/2025
Engine intake charge enrichment with hydrogen (H2) is one way to enhance engine thermal efficiency and decrease pollutant emissions while replacing carbon-based fuel. Waste energy from hot exhaust gas can be thermochemically recovered as hydrogen in catalytic exhaust gas fuel reforming, which can then be used in combustion. This study focuses on tailoring the design of the fuel reformer, including the catalyst chemistry and coating on ceramic and metallic structures, to benefit the whole system’s fuel economy and decrease engine out emissions. The main reformer improvements focused on exhaust flow management and interaction with the engine's after-treatment system, while the final stage focused on the reformer's internal design structure. The new design iteration enabled hydrogen production improvements between 78% and 86% in the critical exhaust gas temperature range of 410°C to 520°C with gas hourly space velocities (GHSVs) in highly demanding engine operating conditions ranging from 16,000 h-1 to 81,000 h-1. The integration of the new fuel reformer with a modern, turbocharged, 2.0 L Hyundai GDI engine raises the fuel efficiency through a combination of higher exhaust energy recovery, improved engine thermal efficiency, and enhanced combustion at highly dilute operation. The engine fuel economy at nine engine speed and torque operating conditions was improved from around 0.5% to 7.88%, with an average of 4.62%.
Lee, Seung Woo, Wahbi, Ammar, Herreros, Jose, Zeraati Rezaei, Soheil, Tsolakis, Athanasios, Millington, Paul
Evaluating the Impact of Displacing Injected Gasoline with Aspirated Ammonia in a Direct Injection Spark Ignition Engine2025-01-02266/16/2025
Replacing fossil fuels with renewable ammonia could provide a crucial step towards the decarbonisation of transport sectors. However, many challenges remain in utilising ammonia within combustion systems: the volumetric energy density of ammonia is significantly lower than that of gasoline, exposure to ammonia (including ammonia slip) can be detrimental to human health, and the production of emissions, including unregulated emissions (such as N2O), from ammonia combustion can be catastrophic for the environment if not treated appropriately. Therefore, there is a need to determine the efficacy of ammonia as a fuel for internal combustion engines and the impact on the efficiency of energy release and the resulting exhaust emissions. A modern spark ignition engine was modified such that ammonia was aspirated through the engine intake air to incrementally displace engine gasoline and maintain a constant work output. It was found that displacing the fuel energy supplied by direct injected gasoline with premixed ammonia by 10% to 40% on an engine work performed basis decreased the peak HRR (heat release rate) and delayed combustion. Spark timing was also advanced to up to 20 CAD BTDC (crank angle degrees before top dead centre) for fuel blends incorporating up to 40% ammonia to allow for optimal conversion of chemical energy to useful work. The corresponding exhaust emissions analysis showed a linear decrease in CO2, however, an exponential decrease in CO as the proportion of ammonia increased. Additionally observed was an initial increase in unburnt hydrocarbons followed by a decrease as peak HRR decreased. However, a clear effect of ammonia level on NOx emissions was not apparent.
Sivaranjitham, Annaniya Mitchell, Hellier, Paul, Ladommatos, Nicos, Millington, Paul, Alcove Clave, Silvia
“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
Techniques and Analysis Methods Used in Development of 13.4kW Horizontal Water-Cooled Diesel Engine2024-32-01164/18/2025
Horizontal water-cooled diesel engines are single-cylinder engines equipped with all the necessary components for operation such as a fuel tank and a radiator. Due to their versatility, there are used in a wide range of applications in Asia, Africa, South America, etc. It is necessary to comply with strengthened emissions regulations year by year in countries where environmental awareness is increasing such as China, India, etc. We have developed a new compact and high-power 13.4kW(18HP) engine which meets these needs. We realized a high-power density by using our unique expertise to maintain an engine size and increase a displacement. In addition, by optimizing a layout of crankcase ribs through structural analysis, we have achieved a maximum bore and “Reduction of the weight of the crankcase and lubricating oil consumption (LOC), and reduction of friction with narrow-width low-tangential load piston rings”. Furthermore, by designing an intake port using 3D CFD, we have optimized a swirl ratio and improved a flow coefficient to improve a fuel efficiency. About conforming to emissions regulations, we utilized 3D CFD to select an optimized nozzle specification and 1D CAE to optimize internal EGR. As a result, we have showed a potential to conform to “Limits and measurement methods for exhaust pollutants from diesel engines of non-road mobile machinery (CHINA IV)” for the new engine with a mechanical injection system. This paper introduces the technology to achieve a high-power density, a low fuel consumption, a high durability and a compliance with emissions regulations simultaneously.
Shiomi, Kenta, Hosoya, Ryosuke, Komai, Yoshinobu, Takashima, Yusuke, Kitamura, Takahiro, Fujiwara, Tsukasa, Suematsu, Kosuke
DoE-Based Numerical Optimization of Intake and Exhaust Port Geometry of a Small Opposed-Piston 2-Stroke (OP2S) Hydrogen Engine2024-32-00544/18/2025
The future potential of an opposed-piston two-stroke (OP2S) engine has attracted the attention of researchers worldwide as it offers a high thermal efficiency and power-to-weight ratio with a simple engine configuration. This engine can be used with low-carbon fuels and hydrogen to reduce greenhouse gas emissions. However, the two-stroke operation has always been limited by its low scavenging efficiency and short-circuit of fresh charge. The current work is focused on optimizing scavenging efficiency and short-circuit in a small 200 cc single-cylinder OP2S SI engine using 3-D computational fluid dynamic (CFD) simulations. The effect of four parameters, namely, area of intake ports, area of exhaust ports, and angular orientations of intake ports (swirl and tilt) on scavenging efficiency and short-circuit, has been assessed and optimized. A Latin-hypercube based Design of Experiments (DoE) methodology is used to sample the design space spanning over a range of four parameters. A response surface is generated using the Kriging method, and the geometry of intake and exhaust ports have been optimized for maximum scavenging efficiency and minimum short-circuit using a genetic algorithm on the response surface. The results show that the scavenging efficiency improves with the increase in exhaust port area, but it also increases the short circuit of fresh air. The Intake port swirl angle significantly impacts scavenging efficiency and short-circuit. The current optimization process achieved a scavenging efficiency of 85% (percentage of the total mass in the cylinder) and a short circuit of 12% (percentage of trapped fresh air). Apart from the geometric parameters, the effect of intake boost pressure and the engine speed on scavenging efficiency and short-circuit has also been evaluated.
Singh, Saurabh, Boggavarapu, Prasad, Himabindu, M., Ravikrishna, R.V.
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
Innovative Use of Basic Technologies for a High-Efficiency, Low-Cost Small Displacement Gasoline Engine2025-01-83924/1/2025
India, with its low per capita income vast population and growing middle class, represents a significant market for low-cost, fuel-efficient automobiles. As the largest two-wheeler market globally, a transition to four-wheelers is underway, further driving the demand for affordable vehicles. This necessitates the design and development of low-priced vehicles equipped with efficient and economical powertrains. Globally, stringent regulations like Corporate Average Fuel Economy (CAFE), Worldwide Harmonized Light Vehicles Test Cycles (WLTC), and Real Driving Emissions (RDE) are pushing manufacturers to develop fuel-efficient vehicles. India has also adopted similar regulations, including CAFE2 and Bharat Stage 6-Phase 2 (BS6-2), to improve fuel economy and reduce emissions. These regulations, coupled with the growing demand for affordable vehicles, have spurred innovation in engine technology. In response to these challenges, Maruti Suzuki India Limited (MSIL) has consistently focused on enhancing the efficiency of its small gasoline engine (0.8L) for entry-level hatchbacks. This has been achieved through a series of technological advancements implemented across multiple generations of the engine. Figure 1 flashes the overview of generation wise technologies upgradation and Gen-3 is the latest one with the highest efficiency in its segment.
Singh, Amandeep, Singh, Jaspreet, Jalan, Ankit, Kumar, Narinder
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
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
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