Browse Topic: Turbochargers

Items (1,285)

Simultaneous Reduction of NOx and Fuel Consumption for Off-Road Powertrains

2026-01-0296

4/7/2026

Simultaneously reducing criteria pollutants and fuel consumption is important for clean air and improving vehicle total cost of ownership. The goal of this effort was focused on a 90% NOx reduction and 10% fuel savings for an off-road 407 kW diesel engine. The baseline was a production Fiat Powertrain 13L engine and aftertreatment system meeting 0.4 g/kW-hr NOx. The baseline system was quantified over the NRTC, RMC, new low load cycle and five field cycles. A next generation engine was built incorporating several fuel-efficient design features, including a higher compression ratio, increased fuel-rail pressure, low-friction piston rings, and a high-efficiency variable-geometry turbocharger. Cylinder deactivation and EGR pump technologies were added to this engine as well. The combination was optimized prior to adding advanced aftertreatment systems, showing the trade-off of engine out NOx and exhaust temperature. Two next-generation catalyst technologies were employed into a LO-SCR plus main SCR system, both with and without an electric heater upstream of the LO-SCR. These catalysts were hydrothermally aged to simulate significant field use. Dual SCR dosing with newly developed controls played a critical role in achieving the proper split between the upstream LO-SCR and the downstream main SCR. Adding a next generation mixer for the downstream SCR proved essential in obtaining the final results. The optimal configuration required adding an electric heater to elevate the exhaust temperature at the LO-SCR for early cycle NOx reduction. The final results showed a 94.8% NOx reduction and 15.7% fuel savings on the composite NRTC.

McCarthy, Jr.,, James, Wine, Jonathan, Bradley, Ryan, Hasseman, Andy, Prikhodko, Vitaly, Howell, Thomas

Improving Transient Diesel Performance with E-Supercharging and Multiple-Input Multiple-Output Controls

2026-01-0444

4/7/2026

Torque transients are challenging for turbocharged diesel engines. Engine torque response is limited by the lag in air flow, restricting the rate at which fuel can be delivered to avoid high engine-out soot emissions. Electrified forced induction systems (EFIS) offer a solution to address this challenge. In this study, an electrified supercharger (e-supercharger) is utilized in addition to the stock turbocharger on a 4.5-L 4-cylinder diesel engine to create a two-stage boosting system. Two control strategies were studied for e-supercharger control during engine transients, a model-based single-input single-output (SISO) controller and a model-based robust multiple-input multiple-output (MIMO) controller. Constant speed load acceptance (CSLA) experiments and emulated drive-cycles were performed to evaluate the performance of each control method. In-cylinder pressure measurements were acquired and apparent heat release calculations were performed and analyzed to better understand the transient engine response. The e-supercharged two-stage boosted engine demonstrated significant improvements over the baseline engine when using both control approaches. The rate of transient power generation was improved by as much as 59.4% resulting in reduced engine speed droop and decreased engine speed recovery time. Transient engine-out soot emissions were also reduced. Although both control approaches improved transient response relative to the baseline engine, the MIMO controller showed the greatest potential for future improvements.

Vang, Nicholas, Rothamer, David, Ghandhi, Jaal, Ashta, Shubham, Qiu, Weijin, Rayasam, Sree Harsha, Shaver, Greg, Frushour, Bryan, Dou, Danan

Model-Based Development of a Heavy-Duty H ₂ -ICE and Integrated, Turbogeneration, Electrification, and Supercharging (ITES) System

2026-01-0426

4/7/2026

Changing global economic conditions and efforts to reduce greenhouse gas emissions are driving the need to develop efficient, near-term, alternative propulsion system technologies for heavy-duty vehicles. This study combines a hydrogen internal combustion engine (H2-ICE) with electrically assisted turbocharging, exhaust energy recovery, and mild hybridization to maximize propulsion system efficiency and reduce NOx emissions. To reduce cost and packaging impact of integration of these technologies on an engine, the study presents a model-based development and optimization of an Integrated Turbogeneration, Electrification, and Supercharging (ITES) system that combines the enabling components into a single compact unit. In the first phase of this study, a H2-ICE and aftertreatment concept for a MY2027 7.7L medium heavy-duty on-road engine was developed and evaluated through 1D simulation. The concept was to convert a diesel engine by changing the cylinder head to implement a port fuel injection (PFI) lean H2 SI combustion system with two-stage turbocharging and no external EGR. The concept was optimized for compression ratio, valve lift profiles, turbocharging, aftertreatment size/specification, and calibration using 1D system simulation in GT-SUITE. In the second phase of this study, the H2-ICE concept performance was further improved by integrating the ITES system and evaluated through 1D simulation. The ITES system replaces the conventional low-pressure stage of the boosting system and adds the capability of electrically assisted turbocharging, turbogeneration from exhaust energy, and P1 mild-hybridization. Applying a model-based approach, the H2-ICE & ITES component sizes were optimized for the best performance and emissions benefit. Using 1D simulation of validated models, the efficiency benefit of the ITES system on engine and vehicle level system was predicted. Finally, a vehicle level simulation was conducted comparing the fuel consumption between a conventional advanced boosting system H2-ICE concept and H2-ICE+ITES concept for Class 6-7 medium heavy duty truck application.

Bustamante, Oscar, Correia Garcia, Bruno, Joshi, Satyum, Franke, Michael

Passive Soot Regeneration Observations on a GPF Equipped Vehicle for PM Exhaust Emission Control

2026-01-0366

4/7/2026

An on-road study has been conducted where a modern vehicle with a 3L turbocharged, PFDI gasoline engine was upfitted with appropriately sized uncoated GPFs for soot capture in a dual-bank exhaust line. The tested GPFs, whether clean or pre-loaded, were weighed to track their soot-load trends between representative real-world driving routes, where sensor data and exhaust temperature data was recorded. Thus, characterization of the passive soot regeneration process in the uncoated GPF was linked to elevated temperatures and vehicle drive cycles speeds.

Craig, Angus, Warkins, Jason

On-Engine Measurement of Automotive Turbocharger Turbine Blade Vibration

2026-01-0201

4/7/2026

Automotive turbochargers are carefully designed to avoid resonance of the turbine blades and backwall, which can result in High Cycle Fatigue failures. Blade Tip Timing is an established technique which utilizes fiber optic probes to measure turbine blade displacements in real time on turbochargers spinning at upwards of 150,000 RPM. Historically, Blade Tip Timing measurements of automotive turbochargers have been made under steady-state conditions using a Hot Gas Stand. In an industry first, General Motors conducted testing of a turbocharger on a running gasoline engine to capture realistic exhaust pressure dynamics. A reference turbocharger was measured on an engine testbed running a production calibration; the same turbocharger was then tested on a Hot Gas Stand to observe how the blade behavior changed. Blade displacements were found to be lower on engine, because the dynamics of engine pulsation reduced the in-phase work available to drive the turbine blades, resulting in lower blade stresses and an improvement in calculated blade fatigue life. Testing also confirmed that key blade resonances had been successfully moved out of the operating space of the engine. Additionally, blade vibration was measured at multiple temperatures on the hot gas stand, and a clear trend was observed between blade temperature and frequency of vibration. The conclusion is that the new turbine design is ready for adoption and poses no concerns for High Cycle Fatigue. While on-engine testing is more challenging to perform, significant advantages are noted; on-engine testing provides a more realistic life estimate for turbine stages than can be obtained using hot gas stand data alone.

SCHWARZ, JORDAN, Goodheart, Rachel, Tappert, Peter, DePaoli, Dominic, Longacre, Christian

Computational Fluid Dynamic and Fatigue Analysis of Turbocharger Turbine Wheel

2026-28-0070

2/12/2026

Turbochargers are essential for improving engine efficiency by compressing air and delivering it to the engine at higher pressure, thereby increasing power output. The turbine wheel in a turbocharger operates under severe mechanical and thermal stresses, making it highly susceptible to fatigue failure, which can occur even under conditions below the rated operating load. To ensure long-term reliability, detailed analysis of the turbine’s fatigue life is essential. This study combines computational fluid dynamics with fatigue analysis to predict the performance and lifespan of a turbocharger's turbine wheel, with a focus on Inconel alloys known for their durability in extreme conditions. A numerical mesh analysis, employing 1,165,610 nodes, was conducted to achieve convergence for both temperature and stress evaluations, leading to the selection of a 2 mm mesh size. Pressure contours at the turbine-fluid interface revealed a pressure range between 1.09 and 1.05 bar, with most of the turbine maintaining a temperature of 700°C, indicating an isothermal condition. Fatigue life predictions using the Geber model, effective for ductile materials, highlighted localized reductions in life expectancy around the blade tip, while most components maintained a factor of safety between 3 and 4, with a maximum of 15. Considering creep effects at 700°C, the turbine's safe operational life was estimated at 591 days. These findings were used to recommend critical design modifications to enhance the turbine’s durability and performance.

Chelladorai, Prabhu, Balakrishnan, Navaneetha Krishnan, G, Naresh, T J, Sreejaun

TwinAV: Valve Timing Strategy for Divided Exhaust Periods in Turbocharged Spark-Ignition Engines: A Simulation-Based Evaluation

03-19-01-0002

2/6/2026

Turbocharging is a common and simple method to utilize the exhaust heat of an internal combustion engine. However, conventional turbocharging exhibits the drawback of exhaust gas backpressure and thus increased residual gas mass in the cylinder. A promising concept to increase optimum efficiency is found in the TwinAV concept, which assigns divided exhaust valve cam timing and exhaust manifold configuration. This concept is hypothesized to reduce the static backpressure in the gas exchange loop and the residual exhaust gas amount in the gas exchange phase. In this article, a 1D simulation model was adapted to an existing 4-cylinder gasoline TC engine. Subsequently, the engine concept was applied to this engine model, whereas the focus was to achieve an engine layout for the entire engine speed range applicable for use in passenger vehicles. The results were compared at the full RPM range. Also, a load variation was conducted and benchmarked. The found results show an additional specific fuel consumption benefit of 6.4%, which is partly achieved by the reduced static backpressure and partly a result of less knock sensitivity due to less remaining internal EGR, observed in an earlier CA50 and peak pressure position. Simulation results indicate benefits in the upper half of the engine map and a maximum benefit in a region around the engines’ sweet point. This is a conceptual simulation-based study; no experimental or transient validation has been conducted.

Gotter, Andreas, Gotter, Alexander

Engine Management System Strategies for Mitigating Dual Mass Flywheel Resonance in Gasoline Powertrains

2026-26-0052

1/16/2026

In today’s fast paced and competitive automotive market, meeting the customer’s expectation is the key to any OEM. This has led to development of downsized high performance engines with refinement as an important deliverable. However developing such high output engines do come with challenges of refinement, especially higher torsional vibrations leading to transmission noise issues. Hence, it becomes important to isolate the transmission system from these high torsional vibration input. To address this, one of the most common method is to adopt Dual Mass flywheel (DMF) as this component dampens torsional vibrations and isolates the transmission unit from the same. While Dual Mass Flywheel assemblies do great job in protecting the transmission units by not allowing the oscillations to pass through them, they do have their own natural resonance frequency band close to the engine idle (low) engine speeds, which must be avoided for a continuous operation otherwise it may lead to Dual Mass Flywheel failures. Thus, there is a requirement for hardware design to keep such band away from the engine operating zone, however it is not feasible to completely avoid it. One of the effective way to eliminate the failures is quickly move out of such resonance speed band & not to continuously stay in critical zone. To overcome this issue, an innovative engine control strategies (EMS) were developed and implemented to protect DMF. These strategies not only ensure that the DMF remains away from the resonance band in various operation conditions, but also enable a robust refinement in the powertrain operations. This paper discusses the study of different strategies, its implementation & validation for DMF Safety and reliability in Turbocharged gasoline engine under different operating conditions.

Raiker, Rajan, viswanatha, Hosur C, Jadhav, Aashish, Jain, Ojase, Jadhav, Marisha

Evaluation of Driveline NVH Performance Using Linear Dynamic Finite Element Simulation

2026-26-0322

1/16/2026

Automotive driveline design plays an important role in defining a vehicle’s Noise, Vibration and Harshness (NVH) characteristics. Driveline system, responsible for torque transfer from the engine/transmission to the wheels, is exposed to a wide spectrum of vibrational excitations. The industry’s shift toward turbocharged engines with fewer cylinders while maintaining the equivalent torque and power has led to increased low-frequency torsional vibrations. This paper presents some key design considerations to drive the NVH design of a driveline system using linear dynamic FE simulations. Using an E-W All-Wheel Drive driveline architecture with independent suspension as a case study, the influence of various subsystem modes on driveline NVH performance is examined. The paper further explores the strategies for vibration isolation, motion control, and mode management to identify the optimal bushing rates and its location. Furthermore, it examines the ideal bushing specifications for different rear differential module (RDM) configurations. Excitation scenarios including propshaft imbalance, engine block vibration, torsional vibration, and axle whine are analyzed as distinct load cases. The study also emphasizes how propshaft mode segmentation affects force transmission to vehicle body under the driveline excitations. The findings contribute to a deeper understanding of driveline NVH behavior and offer practical guidance for achieving improved driveline NVH performance.

Joshi, Atul Kamalakarrao, Subramanian, MANOJ

Key Parameters for Turbocharger Selection & Experimental Validation for off-Highway Applications

2026-26-0104

1/16/2026

Customers in off-highway industry are increasingly seeking high-performance capabilities for their tractors due to increasing penetration of mechanisation and labour scarcity. One effective solution to achieve enhanced performance is turbocharging of engines, while meeting emission and highly dynamic transient response of tractor field applications. The process of selecting and validating a suitable turbocharger for tractor field application suitability is significantly time and resources consuming activity due to extensive testbed and field trials. This study focuses on the selection of turbocharger for tractor engines through analytical calculations to freeze key parameters like lambda, boost pressure ratio & temperature within boundaries of exhaust temperature and turbo efficiency maps to deliver best field transient performance and fuel consumption. The selected parameters are further validated under real-world transient operating conditions, involving tractors and their implements. This approach offers significant advantages by cutting development time and costs for engine while meeting highly dynamic transient performance.

Kumar, Harish Kumar, Rawat, Saurabh, Dogra, DaljitSingh, Singh, Sachleen, Singh, Amarinder

Evaluation of Intercooler Effectiveness with No Fan, Single Fan, and Dual Fan: A Simulation and Experimental Study

2026-26-0579

1/16/2026

Turbochargers play a crucial role in modern engines by increasing power output and fuel efficiency through intake air compression, thereby improving volumetric efficiency by allowing more air mass into the combustion chamber. However, this process also raises the intake air temperature, which can reduce charge density, lead to detonation, and create emissions challenges—such as smoke limits in diesel engines and knock in gasoline spark-ignited (GSL) engines. To mitigate this, intercoolers are used to cool the compressed air. Due to packaging constraints, intercoolers are typically long and boxy, limiting their effectiveness, especially at low vehicle speeds where ram air flow is minimal. This study investigates the use of auxiliary fans to enhance intercooler performance. Two methodologies were adopted: 1D simulation using GT-Suite and experimental testing on a vehicle under different fan configurations—no fan, single fan, and dual fans (positioned near the intercooler inlet and outlet). Results indicated that auxiliary fans significantly enhance heat transfer at low speeds, with dual fans offering the highest improvement—up to 8–13% greater efficiency during hill climb conditions compared to no fan. At high speeds, benefits were negligible (<1%) due to sufficient natural airflow. These results support the application of intercooler fans for improved thermal management under low-speed, high-load conditions.

Patra, Somnath, Hibare, Nikhil, Ganesan, Thanigaivel, Gharte, Jignesh Rajendra

Improving Cold Start and Transient Performance of Medium BMEP CEV Stage V Engines at Low Ambient Temperature and Pressure

2026-26-0142

1/16/2026

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

Simulation Driven Design of Crank-train Systems for Elevated In-Cylinder Combustion Pressures for Existing Architecture

2026-26-0400

1/16/2026

The work demonstrating a novel approach to the optimization of crankshaft design for heavy-duty commercial vehicle engines, specifically targeting non-automotive applications with elevated power ratings. The research focuses on a 6-cylinder, 5.6-litre diesel engine, originally rated at 160 kVA and upgraded to 200 kVA, where the challenge was to enhance the crank-train system’s robustness within existing packaging constraints. By fundamentally altering the crankshaft’s geometry and structural parameters, the new design achieves higher load-bearing capacity while inherently mitigating torsional vibrations, thereby eliminating the need for viscous dampers traditionally used in place of rubber dampers. Advanced simulation tools, notably AVL Excite, employed to iterate and evaluate the balance between crankshaft balance ratio, weight, and torsional behavior. The optimized design then validated through both simulation and physical vibration trials, with sixth-order angular displacement maintained within prescribed limits. Further refinement of the simulation model achieved by optimizing the torsional stiffness of the ring gear to ensure strong correlation with physical measurements. This work demonstrates an effective alternative to viscous dampers and provides a pathway for future crankshaft design in high-power commercial engines.

Khandelwal, Meha, Kaundabalaraman, Kaarthic, Rathi, Hemantkumar

Optimization of a Positive Displacement Type Supercharger Using Response Surface Modeling (RSM)

2026-26-0429

1/16/2026

Air suction in a naturally aspirated engine is a crucial influencing parameter to dictate the specific fuel consumption and emissions. For a multi-cylinder engine, a turbocharger can well address this issue. However, due to the lack of availability of continuous exhaust energy pulses, in a single or two-cylinder engine, the usage of turbocharger is not recommended. A supercharger solution comes handy in this regard for a single or two-cylinder engine. In this exercise, we explore the possibility of the usage of a positive displacement type supercharger, to enhance the air flow rate of a single cylinder, naturally aspirated, diesel engine for genset application, operating at 1500 rpm. The supercharger parametric 3D CAD model has been prepared in Creo, with three design parameters i.e. (a) Generating radius, (b) depth of blower and (c) clearance between lobes & lobe and casing. The optimum roots blower design is expected to fulfil the target boost pressure, power consumption and hydraulic efficiency requirements. The baseline DoE using Sobol algorithm generates 28 designs, which has been simulated using the Ansys CFX software via modeFRONTIER process automation. A sensitivity analysis of the input variables on the response variables establishes that generating radius is the most dominant parameter influencing the pressure, efficiency and power consumption. A detailed Response Surface analysis using 12 different algorithms showed that, Anisotropic Kriging captures the pressure variable accurately, while Gaussian Process captures the efficiency and power consumption with the best accuracy as per R-squared comparison. A virtual optimization conducted using the favorite RSMs using the MOGA algorithm generated an optimum roots blower design which complies all the constraints for pressure, efficiency and power. RSM optimized design is further validated in the CFX software, and the results for response variables are accurate within 6% error margin.

Satre, Santosh Dadasaheb, Mukherjee, Nalini, Rajput, Surendra, Nene, Devendra

Effective Power Management on Diesel Engine Using Electrified Turbocharger

2025-28-0242

11/6/2025

The growing demand for improved fuel efficiency and reduced emissions in diesel engines has led to significant advancements in power management technologies. This paper presents a dual-mode functional strategy that integrates electrified turbochargers to enhance engine performance, provide boost and generate electrical power. This helps in optimizing the overall engine efficiency. The engine performance is enhanced with boosting mode where the electric motor accelerates the turbocharger independent of exhaust flow, effectively reducing turbo lag and provides immediate boost at low engine speeds. This feature also improves high altitude performance of the engine. Conversely, in generating mode, the electric turbocharger recovers or harvest energy from exhaust gases depending on engine operating conditions, converting it into electrical energy for battery recharging purpose. Advanced control systems enable real-time adjustments to boost pressure and airflow in response to dynamic driving conditions, maximizing engine efficiency. Simulation studies and engine testing validate the expected benefits, demonstrating that the electrified turbocharger can significantly facilitate engine downsizing, reduce fuel consumption, and lower emissions through precise power management. These advancements align with global sustainability goals, presenting a viable solution to meet stringent environmental regulations while maintaining robust engine performance. The integration of electrified turbochargers represents a critical step towards the next generation of eco-friendly diesel engines, supporting both environmental sustainability and economic efficiency.

Borle, Shraddha, Prasad, Lakshmi, Couvret, Sebastien, Fournier, Hugo, Chenuet, Laurent

Computational Fluid Dynamics (CFD) Analysis of Turbocharger Aerodynamics and Thermal Behaviour in Automotive Applications

2025-28-0229

11/6/2025

Turbocharging is a vital technology for enhancing internal combustion engine (ICE) performance and efficiency while enabling engine downsizing to reduce fuel consumption and emissions. This research analyzes turbocharger systems by examining their components—turbine, compressor, intercooler, and waste-gate—and their roles in boosting engine efficiency. It explores how exhaust energy drives the turbine to compress intake air, improving power output. The study evaluates turbocharger impact on fuel economy, emissions, and engine response under various driving conditions. It also considers wheel design, material selection, and durability under high temperatures and speeds. Advanced simulations using CFD and FEA analyze airflow, pressure, and thermal behavior to optimize performance. This research affirms turbocharging’s role in creating high-performance, fuel-efficient, and environmentally sustainable engines, offering insights that support the design of next-generation automotive propulsion systems with improved thermal management and emissions control.

Chandrashekar, B. Aditya, Bhaduria, Abhishek

Influence of Twin-Scroll Turbocharging on the Performance of Direct Injection Gasoline Engine

2025-01-5070

10/16/2025

In order to further understand the effect of twin-scroll turbocharging on the engine performance, this paper adopts a combination of one-dimensional numerical simulation and experimental research methods to compare the effects of two-scroll and single-scroll turbocharging on the power and fuel economy of direct injection gasoline engine. The research results show that, compared with the single-scroll turbocharger, twin-scroll turbocharger increased the low-end torque for 16% and 32% at 1000 r/min and 1500 r/min, respectively. However, the average fuel consumption has increased 1.3% at part load with twin-scroll turbocharger due to the pumping loss. Compared with a turbocharged port injection engine with a displacement 1.2 times that of the former, the twin-scroll turbocharged engine saved 11% fuel economy at part loads. The fuel consumption is saved 11% at part loads with twin-scroll turbocharger. This research first establishes the 1D simulation capability in twin-scroll turbocharger, and essentially researches the influence of twin-scroll turbocharger on GDI engine for the first time in China. Twin-scroll turbocharging can increase low-end torque of GDI engine efficiently, take advantage of pulse of exhaust manifolds, eliminate exhaust counter pressure of each cylinder, reduce the residual gas in cylinder so that the anti-knock capability is increased.

Yu, Xiaocao

An Investigation into the Impact of Cylinder Count on the Efficiency of Opposed Piston Two-Stroke Compression Ignition Engines

03-18-06-0037

10/9/2025

The gas exchange process of opposed piston two-stroke (OP2S) diesel engines is primarily driven by the pressure differential between the intake and exhaust, making them susceptible to cylinder-to-cylinder crosstalk, and therefore to cylinder count. This study examined how cylinder count influences brake efficiency in OP2S engines. Using an experimentally validated 1D engine model, three architectures, ranging from two to four cylinders, were created and simulated across their full operating ranges. To isolate the impact of cylinder count, all configurations employed identical cylinder and port geometries, and identical but scaled electrically assisted turbocharger based airpaths. The engines were also controlled to consistent trapped conditions at a given operating condition, resulting in comparable closed-cycle efficiencies. Comparisons were then made using both scaled electrified airpaths and by assuming isentropic airpath work, to assess the impact of airpath efficiency on the results. With electrified airpaths, the two- and four-cylinder architectures had approximately 4.1%rel and 2.2%rel lower brake efficiencies, respectively, than the three-cylinder configuration on average. Additionally, the three-cylinder engine was found to be less sensitive than the other architectures to airpath efficiency, as on a per-cylinder basis it had up to a 17% lower power requirement for the turbocharger compressor, and recovered up to 3% less energy from the turbocharger turbine. These trends were also present when assuming isentropic airpath work, with the magnitude of the efficiency penalty of the two- and four-cylinder architectures reducing to 0.8%rel and 0.6%rel, respectively due to the lower overall magnitude of airpath power requirements. In all cases, the dominant contributor to the above results was the differing scavenging characteristics of the engines due to cylinder-to-cylinder interactions, demonstrating that cylinder count has a measurable impact on OP2S efficiency, and should be a key factor in designing an efficient OP2S engine.

Vorwerk, Erik Scott, Prucka, Robert, Lawler, Benjamin, Huo, Ming

Experimental Measurement of Dynamometer Homologation Cycles in a Dual-Fuel Medium-Duty Engine

2025-24-0036

9/7/2025

Dual-fuel engines employing alternative combustion concepts have shown promising results in meeting significant emission reductions while maintaining engine performance. In the medium and heavy-duty transport sectors, where electrification remains challenging, developing low-temperature combustion is still a technological solution for reducing carbon impact. However, most of the results in this research field have been presented under stationary conditions, which still positions the transient operation as a challenge. One of the main reasons has been the lack of a dedicated control system to manage the load transitions and the inoperability of stock turbochargers to satisfy the EGR dilution ratios and boost pressure to sustain dual-fuel combustion. This study employs a modified 7.7 L dual-fuel engine for its operation in transient conditions by incorporating a prototype turbocharger system. The study addresses the recalibration of the engine to introduce modifications to the injection and air management strategies, allowing for a smoother transition between fully premixed and diffusive combustion modes while maintaining low emissions and similar performance. The study identified the transition from 50% to 75% as the most challenging transition from moving from a fully premixed zone with pressure gradients near the physical limits to a more diffusive combustion region in the engine map. After refining the calibration to allow smooth transitions between loads, transient cycle performance under the World Harmonized Stationary Cycle (WHSC) is experimentally measured, progressively increasing load from 50% to 100%. The results under transient tests confirmed that the recalibration successfully enables full-load operation while mitigating combustion instability and excessive emissions. This research advances the understanding of dual-fuel combustion strategies and highlights the potential of dual-fuel engines as a technological solution for its implementation under real-world vehicle applications in the freight transport sector.

Garcia, Antonio, Monsalve-Serrano, Javier, Marco-Gimeno, Javier, Iñiguez, Erasmo

Using Turbogenerators for Energy Recovery in Turbocharged Hybrid Powertrains

2025-24-0100

9/7/2025

The widespread adoption of battery electric vehicles (BEVs) is progressing more slowly than anticipated, making hybridization crucial for improving efficiency through load point shifting, running the engine at its most efficient operating points and kinetic energy recovery. As the world continues to use fossil fuels, enhancing powertrain efficiency is critical to reducing CO2 emissions. Improved efficiency will also increase the share of renewable e-fuels in the energy mix, supporting the transition to low-carbon mobility. A significant portion of energy in ICEs is lost through exhaust heat, which is a high-grate energy source that can be converted into electricity in hybrid systems. Conventional turbochargers, widely used to enhance volumetric efficiency and drivability, typically incorporate a wastegate (WG) to regulate boost pressure. However, this results in the intentional dumping of excess valuable exhaust energy leading to energy loss. This paper investigates the replacement of conventional wastegate-based turbocharging systems with energy recovery technologies—specifically a turbogenerator and an electrically assisted turbocharger (e-turbocharger)—in a light-duty spark-ignition (LD SI) engine. A fully validated 1D GT-Power simulation model of a production 2.0 L turbocharged engine is used to assess system-level trade-offs in energy recovery, exhaust backpressure, and engine performance. The turbogenerator features a downsized variable geometry turbine (VGT) operating in parallel to the main turbocharger, while the e-turbocharger replaces the conventional turbo system entirely. Parametric simulations evaluate the impact of turbine sizing, mass flow variations, and shaft inertia. Results indicate a maximum recoverable power of up to 21 kW, with realistic net recovery after generator losses in the range of ~ 9–11% of crankshaft power. These findings support the technical feasibility of wastegate-free turbocharging architectures to enhance hybrid powertrain efficiency. Simulation results show that by eliminating WG and implementing a turbogenerator or an e-turbocharger, up to 11.3% of the original crankshaft power – previously lost through WG exhaust can be recovered at high engine loads. This recovered energy can be stored in a battery and reused, contribution to lower CO2 emissions. The findings demonstrate the protentional of such systems to replace conventional turbocharging strategies and pave the way for more energy efficient hybrid vehicle architecture.

Kodaboina, Raghu Vamsi, Vorraro, Giovanni, Turner, James W. G.

Influence of Crankcase Ventilation on Oil-Derived Emissions in a Hydrogen-Fueled Internal Combustion Engine

2025-24-0094

9/7/2025

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

Experimental Study of the Lubricating Oil Impact on the Unsteady Performance of an Automotive Turbocharger

2025-24-0078

9/7/2025

Turbocharging technique is a key technology for the development of hydrogen engines, allowing high lambda values to reach low NOx emissions. In ultra-lean mixture conditions, the thermal management of the lubricating oil and its cold condition becomes a crucial aspect that cannot be neglected. Accordingly, the impact of different lubricating oils and different lubricant thermal conditions is highlighted referring to the performance of a turbocharging system for automotive application. To this aim, an experimental campaign is conducted at the test bench for components of propulsion systems of the University of Genoa. Tests are performed on a turbocharger equipped with a variable geometry turbine under both steady and unsteady flow conditions, considering different positions of the turbine regulating device. A 4-cylinder engine head was coupled to the turbocharger in order to reproduce the pulsating flow related to the opening and closing of the engine valves. The influence of the lubricants on the assessment of turbine thermo-mechanical efficiency is analyzed under steady flow conditions considering different lubricating oils. The study reports the effects of the oil temperature on instantaneous turbine power and turbocharger efficiency under unsteady flow conditions. This analysis aims to provide a comprehensive understanding of turbocharger performance during the engine warm-up phase. The effects of heat transfer between turbocharger components are taken into account, along with the impact of different oil temperatures on friction losses and their effects on the instantaneous rotational speed of the turbocharger. The aim of this work is to provide valuable information on the actual performance of the turbocharger under unsteady flow condition with reference to the impact of the lubricating oil characteristic on the boost pressure provided to the engine.

Marelli, Silvia, Usai, Vittorio, Cordalonga, Carla

Flexible an Low Cost Fuel Consumption Prediction in Heavy-Duty Vehicles Using Machine Learning

2025-24-0121

9/7/2025

This study presents a novel approach for predicting fuel consumption in heavy-duty vehicles using a Machine Learning-based model, which is based on feedforward neural network (FFNN). The model is designed to enhance real-time vehicle monitoring, optimize route planning, and reduce both operational costs and environmental impact, making it particularly suitable for fleet management applications. Unlike traditional physics-based approaches, the FFNN relies solely on a refined selection of input variables, including vehicle speed, acceleration, altitude, road slope, ambient temperature, and engine power. Additionally, vehicle mass is estimated using a methodology presented elsewhere and is included as an input for a better generalization of the consumption model. This parameter significantly impacts fuel consumption and is particularly challenging to obtain for heavy-duty vehicles. Engine power is derived from both engine torque and speed (RPM), ensuring a direct relationship with fuel consumption while keeping computational complexity low. Experimental data were collected from a fleet of heavy-duty trucks under real-world operating conditions. In particular, the study focuses on a turbocharged diesel truck with a maximum power output of 353 kW. The acquisition system is based on an On-Board Unit (OBU) featuring CANbus connectivity, GPS tracking and 4G/LTE-5G communication. The OBU enables continuous logging of vehicle and engine parameters over each mission. Additional road data, such as altitude and slope, were obtained from external mapping services. For the purpose of FFNN development, the training dataset was compiled from approximately 10 different routes, capturing diverse driving conditions, while validation was conducted on 10 independent routes to assess model generalization. Before training, input data were pre-processed using normalization and standardization techniques to ensure stable convergence and mitigate the impact of scale differences among input variables. A correlation analysis was performed to evaluate the relationships among available parameters and fuel consumption, guiding the selection of the most informative inputs. This step reduced redundancy in the dataset and improved network efficiency. Furthermore, hyperparameter optimization was conducted using a Randomized Grid Search algorithm, enabling the identification of an optimal network architecture - specifically in terms of the number of layers and hidden neurons - and training parameters while minimizing overfitting. The final model demonstrated high predictive accuracy across various validation routes, confirming the effectiveness of the FFNN in estimating fuel consumption with a reduced input set. Accuracy was tested on up to 50 routes, whose data where not considered for both training and validation; it was assessed that fuel consumption percentage error per route never exceeded 2%. This approach provides a practical and computationally efficient solution for fleet operators, facilitating advanced route planning and enabling more sustainable transportation strategies through cost-effective fuel management and emissions reduction.

Vicinanza, Matteo, Pandolfi, Alfonso, Arsie, Ivan, Giannetti, Flavio, Polverino, Pierpaolo, Esposito, Alfonso, Paolino, Antonio, Adinolfi, Ennio Andrea, Pianese, Cesare, Frasci, Valentino

High Lambda Boosting for Hydrogen Internal Combustion Engine

02-18-03-0023

8/29/2025

The commercial vehicle industry continues to move in the direction of lower emissions while reducing its carbon footprint. This study focuses on hydrogen internal combustion engines (H2-ICE) since it offers a zero-carbon solution to the industry while showing very low NOx emissions when coupled to a conventionally sized aftertreatment SCR system. This work highlights modeling efforts for analyzing key boosting configurations to operate a hydrogen engine at high lambda (relative air–fuel ratio) for lowering NOx, maintain the aftertreatment system reasonable in size, and improving brake thermal efficiency (BTE). GT-Power was used to model H2-ICE engines from 13L to 19L in displacement with different boosting architectures. Key configurations include a variable geometry turbine (VGT) turbocharger coupled with a supercharger (SC), a VGT with higher engine displacement, and a VGT coupled in series with a fixed geometry turbine (FGT) turbocharger. An exhaustive study comparing these boosting architectures together for steady-state and transient regime performance is the novelty for this study, which is a gap in the existing literatures. Base diesel power curves from both 13L and 15L engines were studied, having maximum brake mean effective pressures (BMEP) from 18 to 21 to 23 bar with λ ≥ 2.2. The VGT+SC was studied with multiple variants including splitting the charge air cooler (CAC) into two parts to provide cooling both pre and post SC, a SC clutch, and a SC bypass. The results show that the VGT (upstream) + SC variant utilizes the SC at low engine speed and high torque, along with all transient regimes from low to high load. The VGT+SC architecture, besides its complexity with clutch and bypass, successfully supports high λ operation (≥2.4), achieving a peak BTE of 43%, and significantly reduces NOx emissions without the need for EGR or large aftertreatment systems. This variant shows the fastest transient response relative to all other configurations in time-to-torque and acceleration cycles while rivaling the highest BTE. VGT+SC can also meet 5500 ft altitude performance with λ ≥ 2.2, leading to low NOx with the same SCR size equivalent to diesel engines and without EGR. Transient response and high BTE are essential to showing that this zero-carbon H2-ICE solution is viable for the commercial vehicle market.

Gurjar, Shubham, McCarthy, Jr., James E., Manickavasagan, Thirumoolan, Chaudhari, Amol S., Nimeshkumar, Parmar, Bachu, Pruthvi, Bitsis, Christopher

Methodology for Selection of Gasoline Catalytic Convertor & Oxygen Sensor Position, Study on Oxygen Storage Capacity for 1.2L Turbocharger MPFI Engine

2025-01-5022

5/16/2025

The results published in this paper emphasize on the study of three-way catalytic convertor for a 1.2 L turbocharged multi-point fuel injection gasoline engine. This paper takes us through the findings on methodology used for finalizing the brick configuration for catalytic convertor along with downstream oxygen sensor placement for emission control and methods applied for catalytic convertor selection with actual testing. The advantages of dual brick configuration over single brick with downstream sensor placed in between the bricks to enable faster dew point of sensor is explained using water splash test and design confirmation of better exhaust gas flow vortices concentration at the sensor tip for better sensing. Selection of catalytic convertor loading by testing its emission conversion capability and light-off behavior. NOx conversion capability across stoichiometric ratio (14.7:1 for petrol) on selected most operational zone was tested (±5% lambda) for the design-finalized samples acquired for testing. Also ability of faster light-off temperature (250–300°C) where conversion efficiency should be >95% is evaluated. Like wise it was also found that emission conversion efficiency is directly proportional to oxygen storage capacity of catalytic convertor with same configuration. On the other hand, an experiment on reverse aging for catalytic convertor was performed to monitor its improvement in oxygen storage capacity.

Arun Selvan, S. A., Paul, Arun Augustine, Selvaraj, Manimaran

Optimization of HEV Vehicle’s Engine Modulated Noise

2025-01-0084

5/5/2025

One 1.5L Miller-cycle turbocharged four cylinder gasoline hybrid engine is installed on a certain hybrid vehicle. When accelerating at low to medium speeds with a small throttle, there is a "da da" knocking noise inside the car, which seriously affects the overall sound quality of the vehicle. By analyzing the vibration and noise data of the engine, it was found that the frequency of the abnormal knocking sound is 200-2000Hz, which presents a half order characteristic in the time domain, that is, one knocking occurs when the engine crankshaft rotates twice. Through Hilbert demodulation analysis of the vibration data in the problem frequency range, it was found that the knocking noise was modulated in the frequency domain, with a modulation frequency of half of the crankshaft rotation frequency. By building a fully flexible multi-body dynamic model of a hybrid powertrain and inputting the engine's cylinder pressure excitation, the combustion excitation is coupled with mechanical vibration noise to simulate the surface vibration of the powertrain. Measures such as optimizing the cylinder pressure curve by adjusting spark angle and scavenging angle, and improving crankshaft stiffness by increasing the overlap between mainbearing diameter and connecting rod diameter, the sound quality issue of this hybrid model has been significantly improved under low speed and low throttle acceleration conditions.

Dan, Kong

WITHDRAWAL NOTICE

2025-01-8253.01

4/1/2025

Assessment of a Heavy-Duty Diesel Engine Retrofitted to Dual-Fuel and Neat Methanol SI Operation

2025-01-8440

4/1/2025

This paper explores the potential of leveraging methanol's knock-resistant properties to facilitate both dual fuel (DF) and spark ignition (SI) operation in retrofitted heavy-duty (HD), high-speed marine engines. The study involves retrofitting an original 6-cylinder 7.15L CI diesel engine with port fuel injection (PFI) of methanol to enable DF operation. Later, the diesel injectors were replaced with six spark plugs allowing SI operation. Notably, efforts were made to minimize adaptations to the existing diesel engine, maintaining the compression ratio (CR) at 17.6:1 and retaining the same turbocharging pressure. This research aims to assess the feasibility of retrofitting conventional HD diesel engines (high CR, large bore) for dual-fuel and SI operation on methanol, with a focus on optimizing engine performance, while preserving key characteristics for HD applications, e.g. high torque and high power density. The high CR required spark retarding to prevent knock at higher loads in SI operation. Despite this, efficiencies comparable with diesel were obtained for both diesel-methanol dual-fuel as SI operation on 100% methanol, although differences were noticeable depending on the load. Tests were performed at 1500 rpm with a BMEP of 3.5, 7.1 and 10.6 bar, respectively 22, 44 and 66% of the maximum engine load. The maximum load achievable in stoichiometric SI operation was 12.3 bar BMEP, corresponding to 77% of the original maximum load with diesel CI. At this load, a brake thermal efficiency of 38.5% at stoichiometric conditions was attained. At lean conditions (λ=1.25) an efficiency of 40.1% was reached, with no significant difference compared to a 40.3% efficiency attained in diesel-only operation.

Dejaegere, Quinten, Ballerini, Alberto, Demiddeleer, Sheldon, Vanderbeken, Thomas, Bracke, Kwinten, Gyselinck, Ben, D'Errico, Gianluca, Verhelst, Sebastian

Theoretical Study of Electrically Assisted Two-Stage Turbocharger Boost System Applied to Large-Bore Gas SI ICE

2025-01-8354

4/1/2025

Large-bore gas SI ICEs are supposed to operate under more strict conditions in terms of NOx level and potentially using new generation of fuels (e.g., hydrogen, ammonia) in the near future. Currently, the TA Luft norm is being considered while typical BMEP levels are between 22-28 bar. It is expected that NOx will have to drop significantly (down to 20% or even below 10% of the amount based on TA Luft) while engine BMEP is supposed to be increased above 30 bar. The paper is based on 0-D/1-D simulations while using the experience gained from older research projects concerning similar engines. The main goal is to study the influence of different operating conditions (e.g., NOx level, BMEP level, control means, ambient conditions) on both ICE performance and turbocharger operation while comparing classical 2-stage system with 2 electrically assisted ones (e-turbo, e-booster) – steady state performance is of the main focus while transient one is also considered. Complex optimizations were carried out to achieve optimal solution for every considered operating case. The main conclusion is that the potential to improve BSFC when e-assisted turbocharging is applied under the steady-state operation is low and it makes sense only under specific conditions. On the other hand, e-assistance significantly improves engine transient response.

Vitek, Oldrich, Macek, Jan, Mares, Bohumil, Klima, Jiri, Vacek, Martin

Enhanced High-Temperature Performance of NH ₃ -SCR Catalysts for Lean-Burn Engines

2025-01-7043

1/31/2025

NOx after-treatment has greatly limited the development of lean-burn technology for gasoline engines. NH3-Selective Catalytic Reduction (SCR) technology has been successfully applied to NOx conversion in diesel engines. For gasoline engines, SCR catalyst is required to maintain high activity over a higher temperature window. In this study, we utilized a turbocharged and intercooled 2.0 L petrol engine to investigate the NOx conversion of two zeolite-based SCR catalysts, Cu-SSZ-13 and Fe/Cu-SSZ-13, at exhaust flows ranging from 80 to 300 kg/h and exhaust temperatures between 550 to 600°C. The catalysts were characterized using SEM, ICP, XRD, H2-TPR, NH3-TPD, and other methods. The selected Fe/Cu-SSZ-13 catalyst showed higher NOx conversion (>80%) in the temperature range of 550~600oC and 80~300 kg/h exhaust gas flow. NOx output could be controlled below 10ppm. The characterization results showed that although the specific surface area and acidic sites decreased after the aging treatment for Fe/Cu-SSZ-13, they still retained active sites, showing higher activity and stability.

Pan, Shiyi, Wang, Ruwen, Zhang, Nan, Xu, Zhiqin, Hu, Jiangtao, Liao, Xiuke, Duan, Pingping, Chen, Ruilian

Vibration Measurement on Diesel Engine Components under Adverse Conditions in Brazilian Application

2024-36-0021

12/20/2024

The objective of this study is to investigate the root cause of cracks detected in the Turbocharger bracket belonging to the engine Mercedes-Benz OM471 (Power: 390kW, Torque: 2600Nm) from Vehicle Truck Mercedes-Benz Actros 2651LS 6x4 Euro V. The investigation started with the instrumentation of every related component (besides the bracket itself, the charge air pipe, the exhaust pipe and also the crankcase for reference) in order to perform a vibration measurement. The necessary equipment to execute this procedure, included accelerometers, temperature sensors, strain gages and an inductive engine speed sensor. All data had to be acquired directly from real application conditions in vehicle, maximum load of 74 ton in a previously defined mountain road track, due to the impossibility to generate similar results in comparison to the ones detected on road through bench tests (or any other in-door experiment). The bracket position is located on the right side of a diesel combustion engine, also known as “engine hot side”, and work under temperatures in a range from 300 to 400 Celsius degrees. The development of a solution to allow the measurements to occur under such inhospitable conditions became a mandatory step of the investigation. The addition of a cooling system for the accelerometers, its adaptation and also the installation in the vehicle had been a challenging operation in order to reach the necessary results. The analysis of the raw data (speed, acceleration, strain and temperature) through Fast Fourier Transformation calculation (FFT) led to the exact determination of the root cause. With a clear understanding of the part behavior, assertive proposals of solution could be developed thanks to the answers obtained in the results of these measurements.

Feijó, Igor Sommerfeld, Gonçalves, Carlos Aurélio Bustamante

Large-Bore HFO Engine Gas Conversion for Power Plants – Part A: Numerical Assessment

2024-36-0160

12/20/2024

In the global scenario marked by the increasing environmental awareness and the necessity on reducing pollutant emission to achieve the decarbonization goals, action plans are being proposed by policy makers to reduce the impact of the climate change, mainly affecting the sectors that most contribute to CO2 emissions such as transportation and power generation. In this sense, by virtue of the National Energy Plan 2050, the Brazilian market will undergo the decommissioning of thermal power plants fueled by diesel and heavy fuel oil (HFO) by 2030, compromising about 6.7 GW of power capacity according to the Brazilian Electricity Regulatory Agency (ANEEL) database. An alternative to the scrapping of these engine power plants is their conversion to operate with fuels with a lower carbon footprint, such as the natural gas. This work, therefore, aims to numerically assess the conversion feasibility of a HFO large bore four-stroke turbocharged engine to operate with natural gas by means of a one-dimensional engine modeling. First, the 1D non-converted engine model operating with HFO is validated with experimental data. Then, the conversion of the HFO engine to natural gas is carried out by adding a wastegate for the air-fuel ratio control, changing the compression ratio and the fuel injection, and introducing the pre-chamber ignition system. At this stage, the performance of the engine operating with most of its stock components is evaluated, including the presence of knock, fuel slip, and components that may not be suitable for NG operation and must be adapted, redesigned, or replaced. After that, modifications on the valve timings are proposed to reduce the methane slip and allows a proper scavenging. In conclusion, this study numerically assessed converting an HFO engine to natural gas, identifying new component specifications and presenting alternatives to maintain engine performance post-conversion.

Gonçalves, Vinícius Fernandez, Zabeu, Clayton Barcelos, Antolini, Jácson, Salvador, Roberto, Almeida, Rogério, Valiati, Allan Soares, Filho, Guenther Carlos Krieger

Fuel Efficiency Evaluation of an Off-Road Diesel Engine with an EGR Pump and High-Efficiency Turbocharger across Various Drive Cycles

02-17-04-0023

12/10/2024

As regulations become more stringent, engine manufacturers are adopting innovative technologies to reduce emissions while maintaining durability and reliability. One approach involves optimizing air handling systems. Eaton developed a 48 V electric exhaust gas recirculation pump (EGRP) to reduce NOx and CO2 emissions while improving fuel efficiency when paired with a high-efficiency turbocharger. This study integrates an electric EGRP and a high-efficiency turbocharger onto a 13.6L John Deere off-road diesel engine to evaluate the impact on fuel efficiency and NOx emissions across various drive cycles including the nonroad transient cycle (NRTC), the low load application cycle (LLAC), the constant speed–load acceptance (CSLA) test, and the ramped modal cycle (RMC). The study highlights the benefits and limitations of the prototype EGRP on an off-road engine. Since the setup did not include aftertreatment systems, engine-out emissions were analyzed. Experiments were conducted at selected operating points to achieve optimal brake thermal efficiency while keeping BSNOx within 25% of baseline values. These results helped develop a calibration map for both transient and steady-state testing. For the CSLA tests, the time response to achieve 90% load was slower with the EGRP-equipped engine compared to the stock engine. Additionally, the NRTC, a regulatory cycle for the United States and the European Union, and the LLAC did not achieve the desired torque set points with the EGRP and high-efficiency turbocharger. The EGRP’s slower-than-desired response when it decelerates led to excess EGR flow, which affected the engine’s ability to produce torque. This was a key finding of the study. The measured engine speed and engine load with the EGRP engine configuration were utilized to develop a modified version of the NRTC and LLAC, referred to in this article as the modified NRTC and the modified LLAC. The modified NRTC and modified LLAC were run on the stock engine to accurately compare the performance of the stock hardware with the EGRP and high-efficiency turbocharger hardware for the same transient cycles, albeit cycles that are no longer specifically the regulatory NRTC and LLAC cycles. The intent of the modified LLAC and the modified NRTC is to show what the possible benefits of EGRP and high-efficiency turbocharging may likely be if the transient response shortcoming of the EGRP is addressed BSFC improved with the EGRP and high-efficiency turbocharger hardware for the modified NRTC, modified LLAC, and RMC. The modified NRTC showed a 1.3% improvement, the modified LLAC exhibited a 2.5% improvement, and the RMC demonstrated a 1.3% improvement. BSNOx increased by 12.9% for the modified NRTC, decreased by 11.1% for the modified LLAC, and increased by 2.8% for the RMC with the EGRP configuration. The BSPM increased by 34.2% for modified LLAC and improved by 33.1% for the modified NRTC.

Willoughby, Audrey, Adekanbi, Michael, Kakani, Raghav, Ahmad, Zar Nigar, Shaver, Greg, Holloway, Eric, Haaland, Eric, Evers, Matthew, Loesch, Adam, McClurg, Josiah, Bagal, Nilesh, McCarthy, James, Coates, Michael

Investigating Methods to Generate Models for Turbine Maps Using Machine Learning

02-17-04-0019

10/9/2024

For turbocharged engine design, manufacturer-provided turbocharger maps are typically used in simulation analysis to understand key engine performance metrics. Each data point in the turbocharger map is generated by physically testing the hardware or through CFD analysis—both of which are time-consuming and expensive. As such, only a modest set of data can be generated, and each data map must be interpolated and extrapolated to create a smooth surface, which can then be used for engine simulation analysis. In this article, five different machine learning algorithms are described and compared to experimental data for the prediction of Cummins Turbo Technologies (CTT) fixed geometry turbines within and outside of the experimental data range. The results were validated against xxx-provided test data. The results demonstrate that the Bayesian neural networks performed the best, realizing a 0.5%–1% error band. In addition, it is extrapolatable when suitable manually created extra data points are incorporated within the dataset at low and high turbine speeds.

Supe, Shreyas, Natarajan, Bharath, Shaver, Greg

Variable Geometry Turbine Turbocharger Optimization Using Machine Learning for On-Highway Fuel Cell Applications

02-17-04-0020

10/7/2024

Turbocharger design involves adjustment of various geometric parameters to improve the performance and suit mechanical constraints, depending on the application-specific requirements. In designing the turbine stage, these parameters are optimized to maximize durability and efficiencies at the required operating points. For a heavy-duty class eight truck, “road load” and “rated power” are generally considered the two most important operating points. The objective of this article is to improve the efficiencies of these two operating points. The common challenge in the development of a turbine wheel design is the large number and interdependence of parameters to optimize. For example, increasing the blade thickness improves structural strength but reduces the mass flow capacity, thus influencing its performance. It is general practice to optimize the wheel geometry using iterative CFD analysis. However, running simulations for every single change in geometry involves significant computation time and does not guarantee the global optimum. This study proposes a machine learning (ML)-driven optimization process for variable turbine geometry (VTG) wheels with two target operating points. Initial CFD data is collected and used to train/validate a ML model for each operating point. A multi-objective optimization algorithm utilizes these ML models to provide a list of ideal turbine wheel designs, and the best candidates are validated in CFD for accuracy. The results are a balanced maximization in efficiency for both operating points, with an improvement in the pareto front by 1.4% points over CFD optimization alone.

Wichlinski, Joseph, Gonser, Lukas, Naik, Pavan, Taylor, Alexander H., Al-Hasan, Nisar S.

Advanced Laser Cleaning Robotic Work Cells Turbocharge Industrial Processes

TBMG-51403

9/1/2024

Today, advancements in industrial laser cleaning automation show great promise in boosting productivity and safety when rust and contaminant removal or surface preparation is required for higher volumes of components and equipment.

An Investigation on Exhaust Pulse Characteristics of Asymmetric Twin-Scroll Turbocharged Heavy-Duty Diesel Engine

03-17-06-0048

7/24/2024

The shape and energy distribution characteristics of exhaust pulse of an asymmetric twin-scroll turbocharged engine have a significant impact on the matching between asymmetric twin-scroll turbines and engines, as well as the matching between asymmetric twin scrolls and turbine wheels. In this article, the exhaust pulse characteristics of an asymmetric twin-scroll turbocharged engine was studied. Experiments were conducted on a turbine test rig and an engine performance stand to determine the operation rules of exhaust pulse strength, turbine flow parameters, turbine isentropic energy, and turbine efficiency. The results showed that the exhaust pulse strength at the inlets of both the small and large scrolls continuously decreased with the increase of engine speed. And the flow parameters at the inlets of the small and large scrolls exhibited a “ring” or “butterfly” shape with the change of expansion ratio depending on the pressure deviation of the extreme points at the troughs on both sides of the “secondary peak” of the exhaust pressure pulse, respectively. Besides, the distribution trend of turbine isentropic power was consistent with the trend of exhaust pressure pulse at the inlets of the small and large scrolls. Furthermore, when opening the balance valve, it caused the appearance of “concave” and “convex” features near the “main peak” and “secondary peak” of the turbine isentropic power pulses, respectively. Finally, as the engine speed increased, the fluctuation of turbine instantaneous efficiency gradually decreased. When calculating the instantaneous efficiency of the turbine, the influence of the rotor’s rotational inertia needs to be considered, otherwise, there may be a false phenomenon of exceeding 100% efficiency.

Wu, Liangqin, Jin, Jianjiao, Wang, Jie, Zhang, Chenyun

Turbocharging System Selection for a Hydrogen-Fuelled Spark-Ignition Internal Combustion Engine for Heavy-Duty Applications

2024-01-3019

7/2/2024

Nowadays, green hydrogen can play a crucial role in a successful clean energy transition, thus reaching net zero emissions in the transport sector. Moreover, hydrogen exploitation in internal combustion engines is favored by its suitable combustion properties and quasi-zero pollutant emissions. High flame speeds enable a lean combustion approach, which provides high efficiency and reduces NOx emissions. However, high airflow rates are required to achieve the load levels typical of heavy-duty applications. In this framework, the present study aims at investigating the required boosting system of a 6-cylinder, 13-litre heavy-duty spark ignition engine through 1D numerical simulation. A comparison among various architectures of the turbocharging system and the size of each component is presented, thus highlighting the limitations and potentialities of each architecture and providing important insights for the selection of the best turbocharging system.

Pucillo, Francesco, Millo, Federico, Piano, Andrea, Giordana, Sergio, Rapetto, Nicola, Paulicelli, Fabio

Numerical Study of Application of Gas Foil Bearings in High-Speed Drivelines

2024-01-2941

6/12/2024

The commitment to environmentally friendly transportation calls for efficient solutions with the evolution of automotive industry. Turbochargers are an important part of this development. The application of Gas or Air Foil Bearings (GFB) instead of traditional hydrodynamic bearings is recently very noticed, with which the fuel consumption, and emissions can be minimized as well as decreasing the maintenance costs and increasing the reliability. However, low viscosity of gas leads to lower dynamic stiffness and damping characteristics resulting in low load carrying capacity and instability at higher speeds. Gas bearings can be enhanced by adding a foil structure commonly known as gas foil bearings whose dynamic stiffness can be tailored by modifying the geometry and the material properties resulting in better stability and higher load carrying capacity. A detailed study is required to assess the performance of high-speed rotor systems supported on GFBs, therefore in this study a bump type GFB is analyzed for its static and dynamic characteristics. The static characteristics are obtained by solving the non-linear Reynolds equation through an iterative procedure. The dynamic characteristics i.e. stiffness and damping coefficients are obtained through a perturbation method, also a direct method to evaluate the stiffness coefficients is obtained and compared. Finite difference method (FDM) is used to solve the system of equations numerically. Two methods of computing the static pressure distribution are evaluated and compared through a detailed static analysis considering the influence of different parameters i.e., eccentricity, clearance, rotor speed and foil compliance of the GFBs on the load carrying capacity. Next, the influence of different parameters of the GFBs on the dynamic stiffness and damping coefficients is also presented.

Mandapalli, Prithvi Raju, Hoefler, Dieter, Rohani, Rezvan

Influences of High-Pressure Pump and Injector Nozzle Geometry on Hydraulics Characteristics of a Mechanical Diesel Direct-Injection System

2024-01-5061

6/4/2024

The geometry of high-pressure pump and injector nozzles crucially influences hydraulic behaviors (e.g., the start of injection, the pressure profiles developed in the high-pressure line, needle lift, and injection rates) in diesel engines. These factors, in turn, significantly impact fuel atomization, fuel–air mixing, combustion quality, and the formation of emissions. The main geometry parameters such as plunger diameter and the number and diameter of nozzles lead to the system complexity, requiring careful analysis, design, and calibration. In this study, a high-speed shadowgraph system and a high-resolution pressure recording system were developed to capture the start of injection, spray structure, and pressure profiles in the high-pressure line. Additionally, a model was developed using GT-Fuel package built within the GT-Suite of simulation tools to explore different plunger diameters and numbers and diameters of injector nozzles. These models were validated using the pressure profiles, fuel quantity, and start of injection timing obtained from the experiments. This approach can either individually analyze the influence of each parameter or assess their overall impact. The results indicate that an increase in plunger diameter advances the start of injection (SOI). Furthermore, an increase in the number and/or diameter of nozzles results in a higher amount of fuel delivered per cycle. Overall, replacing an injection system with 10 mm plungers and injectors with 7 × 250 μm nozzles with one featuring 12 mm plungers and injectors having 8 × 300 μm nozzles can increase the fuel delivery by 1.85 fold. This approach could be useful for practical applications, including turbocharging engines and/or designing more efficient fuel systems. Future investigations into the high-speed shadowgraph images captured in this study could offer additional insights into the Rayleigh–Taylor and Kelvin–Helmholtz models concerning the primary and secondary atomization processes.

Nguyen, Quan Q., Vu, Manh D., Phung, Duoc V., Nguyen, Kien T., Vu*, Tuan N., Pham, Phuong X.

Auto-Ignited Combustion Control in an Engine Equipped with Multiple Boosting Devices

03-17-06-0043

6/3/2024

The combustion timing of auto-ignited combustion is determined by composition, temperature, and pressure of cylinder charge. Thus, for a successful auto-ignition, those key variables must be controlled within tight target ranges, which is challenging due to (i) nature of coupling between those variables, and (ii) complexity of managing multiple actuators in the engine. In this article, a control strategy that manages multiple actuators of a boosted homogeneous charge compression ignition (HCCI) engine is developed to maintain robust auto-ignited combustion. The HCCI engine being considered is equipped with multiple boosting devices including a supercharger and a turbocharger in addition to conventional actuators and sensors. Since each boosting device has its own pros and cons, harmonizing those boosting devices is crucial for successful transient operation. To address the multi-variable transient control problem, speed-gradient control methodology is applied to minimize coupling between boosting devices. Simulation results show that the control strategy overcomes turbo lag by utilizing the supercharger during transient. The controller developed is still appliable to manage multiple boosting devices with conventional engines as well as HCCI engine.

Kang, Jun-Mo

Centrifugal Compressor Map Prediction Based on Geometrical Parameters with Invariant Coefficients

2024-01-5056

4/24/2024

In the present work, a new methodology for predicting the performance of centrifugal compressors is developed. The proposed method differs from existing methods found in literature by gathering principal losses in three parameters: two constants and one variable, which is a function of the compressor wheel geometrical characteristics. As those parameters are constants for a given centrifugal compressor, there is no need for additional corrective parameters in order to obtain coherent results. Indeed, the proposed methodology does not depend on the choice of the slip factor correlation for the prediction of the correct pressure ratio. However, the choice of slip factor influences the efficiency computation. The prediction of the compressor maps for two full stage centrifugal compressors is presented and they show good agreement while compared with manufacturer’s data obtained from gas stand measurements. In addition, a method to obtain the surge line based on this methodology is proposed and validated with good accuracy while compared with experimental and manufacturer’s data. A correction of the surge line parameter is proposed for ported shroud configurations. A final evaluation of the methodology using two well-documented Eckardt’s impellers with higher mass flow rates is presented showing a good prediction for back-sweep angle impellers and lower agreement with radial exit impellers.

Martinez Alvarado, Luis Enrique, Milosavljevic, Misa

Evaluating the Effects of an Electrically Assisted Turbocharger on Scavenging Control for an Opposed Piston Two Stroke (OP2S) Compression Ignition Engine

2024-01-2388

4/9/2024

Opposed piston two-stroke (OP2S) diesel engines have demonstrated a reduction in engine-out emissions and increased efficiency compared to conventional four-stroke diesel engines. Due to the higher stroke-to-bore ratio and the absence of a cylinder head, the heat transfer loss to the coolant is lower near ‘Top Dead Center.’ The selection and design of the air path is critical to realizing the benefits of the OP2S engine architecture. Like any two-stroke diesel engine, the scavenging process and the composition of the internal residuals are predominantly governed by the pressure differential between the intake and the exhaust ports. Without dedicated pumping strokes, the two-stroke engine architecture requires external devices to breathe. In the unique OP2S engine architecture studied in this work, the external pumping devices present in the air path include an electrically assisted turbocharger (EAT), an electrified EGR pump, and a back-pressure valve (BPv) located downstream of the turbocharger. In this work, various sweeps were experimentally recorded for these actuators to understand their effects on airflow rate, port pressure, and pressure differential. The objective of these experiments was to identify regions with high scavenging efficiencies while evaluating the effect of electrical power consumption as pumping losses on brake efficiency. The results indicated a higher scavenging efficiency was achievable at low engine speeds as less of the fresh intake charge is short-circuited to the exhaust during the blow down process. Also, with the combination of these actuators, an inherent challenge of decoupling airflow control from intake port pressure became apparent, and thus optimizing scavenging at a given port pressure became difficult. However, the EAT provides the flexibility of changing the air flow rate at a constant load but any increase in the brake thermal efficiency is negated by the electrical energy consumed from pumping more air through the compressor.

Bhatt, Ankur, Gandolfo, John, Huo, Ming, Gainey, Brian, Lawler, Benjamin

Assessing the Effects of Computational Model Parameters on Aerodynamic Noise Characteristics of a Heavy-Duty Diesel Engine Turbocharger Compressor at Full Operating Conditions

2024-01-2352

4/9/2024

In recent years, with the development of computing infrastructure and methods, the potential of numerical methods to reasonably predict aerodynamic noise in turbocharger compressors of heavy-duty diesel engines has increased. However, aerodynamic acoustic modeling of complex geometries and flow systems is currently immature, mainly due to the greater challenges in accurately characterizing turbulent viscous flows. Therefore, recent advances in aerodynamic noise calculations for automotive turbocharger compressors were reviewed and a quantitative study of the effects for turbulence models (Shear-Stress Transport (SST) and Detached Eddy Simulation (DES)) and time-steps (2° and 4°) in numerical simulations on the performance and acoustic prediction of a compressor under various conditions were investigated. The results showed that for the compressor performance, the turbulence models and time-step parameters selection were within 3% error of the simulated and experimental values for pressure ratio and efficiency. Under high-efficiency conditions, in a fixed time step, the use of SST could achieve high prediction accuracy in pressure ratio and efficiency. For aerodynamic noise prediction, at both the blade passing frequency and its first order harmonic frequency could obtain the significant peak values of power spectrum density (PSD) for four model parameters. In addition, the turbulence models with 4° time step showed lower PSDs at high frequency (more than 15000 Hz) as compared with the PSDs of 2° time step in volute region under near-surge condition. Therefore, based on the trade-off relationship between computational accuracy and time cost, the SST model combined with the 4° time step was the best choice for the calculation of compressor performance and aerodynamic noise prediction at various conditions.

Huang, Rong, Ni, Jimin, Wang, Qiwei, Yin, Qi

3-Dimentional Numerical Transient Simulation and Research on Flow Distribution Unevenness in Intake Manifold for a Turbocharged Diesel Engine

2024-01-2420

4/9/2024

The design of engine intake system affects the intake uniformity of each cylinder of the engine, which in turn has an important impact on the engine performance, the uniform distribution of EGR exhaust gas and the combustion process of each cylinder. In this paper, the constant-pressure supercharged diesel engine intake pipe is used as the research model to study the intake air flow unevenness of the intake pipe of the supercharged diesel engine. The pressure boundary condition at the outlet of each intake manifold is set as the dynamic pressure change condition. The three-dimensional numerical simulation of the transient flow process in the intake manifold of diesel engine is simulated and analyzed by using numerical method, and the change of the Intake air flow field in the intake manifold under different working conditions during the intake overlapping period is discussed. The dynamic effects of diesel engine intake boost pressure, rotated speed, and intake pipe geometrical characteristic on the air mass flow at the outlet of each intake manifold, intake air distribution quality, and maximum intake unevenness are analyzed. According to numerical calculation result, it was obtained that the main reasons affecting the intake unevenness of each cylinder of diesel engine and the methods to reduce the intake unevenness: The lower the intake boost pressure of diesel engine, the greater the maximum intake unevenness. The greater the intake overlapping angle, the greater the maximum intake unevenness. When the diesel engine was working at low rotated speed, the maximum intake unevenness was higher than that at high rotated speed due to the long intake overlapping time. By increasing the boost pressure of the intake air, the unevenness intake air distribution of the diesel engine during the intake process could be reduced.

Yang, Shuai, Yan, Kai, Liu, Haifeng, Fu, Yahao, Liu, Hairan, Li, Tong

Post-Oxidation Phenomena as a Thermal Management Strategy for Automotive After-Treatment Systems: Assessment by Means of 3D-CFD Virtual Developmen t

2024-01-2629

4/9/2024

The target of the upcoming automotive emission regulations is to promote a fast transition to near-zero emission vehicles. As such, the range of ambient and operating conditions tested in the homologation cycles is broadening. In this context, the proposed work aims to thoroughly investigate the potential of post-oxidation phenomena in reducing the light-off time of a conventional three-way catalyst. The study is carried out on a turbocharged four-cylinder gasoline engine by means of experimental and numerical activities. Post oxidation is achieved through the oxidation of unburned fuel in the exhaust line, exploiting a rich combustion and a secondary air injection dedicated strategy. The CFD methodology consists of two different approaches: the former relies on a full-engine mesh, the latter on a detailed analysis of the chemical reactions occurring in the exhaust line. The coupling between experimental data and simulation results provides a complete assessment of the investigated phenomena. After the validation of the numerical methodology for one fixed engine operating point, a specific investigation is performed to assess the benefits of post-oxidation in terms of catalyst light-off time. Finally, the simulation strategy is applied considering a different fuel: hydrogen. Accordingly, both the full-engine mesh simulation and the detailed analysis of the exhaust line are performed. The 3D-CFD virtual development allows a comparison between the results obtained through gasoline and hydrogen, thus highlighting the differences and the possible improvements associated with the application of the alternative fuel and the exploitation of its peculiar features.

Barillari, Loris, Pipolo, Mario, Della Torre, Augusto, Montenegro, Gianluca, Onorati, Angelo, Vacca, Antonino, Chiodi, Marco, Kulzer, André

Water Droplet Collison and Erosion on High-Speed Spinning Wheels

03-17-05-0037

4/4/2024

The water droplet erosion (WDE) on high-speed rotating wheels appears in several engineering fields such as wind turbines, stationary steam turbines, fuel cell turbines, and turbochargers. The main reasons for this phenomenon are the high relative velocity difference between the colliding particles and the rotor, as well as the presence of inadequate material structure and surface parameters. One of the latest challenges in this area is the compressor wheels used in turbochargers, which has a speed up to 300,000 rpm and have typically been made of aluminum alloy for decades, to achieve the lowest possible rotor inertia. However, while in the past this component was only encountered with filtered air, nowadays, due to developments in compliance with tightening emission standards, various fluids also collide with the spinning blades, which can cause mechanical damage. One such fluid is the condensed water in the low-pressure exhaust gas recirculation channel (LP-EGR) formulated at cold starts and low-speed high load conditions. This kind of design has been developed to reduce nitrogen oxide emissions and is used in both gasoline and diesel engines. This article presents a state-of-the-art review of this WDE process, focusing on the formation of the condensed water before the compressor wheel, summarizing the influencing factors of WDE and the effects of the damage including using component testbench experiences and simulation methodologies. Inspection possibilities such as high-speed camera measurement and vibration analysis are also an important part of the document.

Takács, Richárd, Zsoldos, Ibolya, Szentendrei, Dániel

2025 Kia Carnival MPV Hybrid brings unplugged PHEV power

24AUTP04_12

4/1/2024

The 2025 Kia Carnival MPV is acquiring a hybrid powertrain as part of the minivan's model year update that debuted at the Chicago Auto Show. The internal-combustion engine option remains the 3.5-L V6 GDI seen in the current Carnival and produces 287 hp and 260 lb-ft (353 Nm) that powers the front wheels through an 8-speed automatic transmission. Engine power is down slightly from the output of the V6 in the 2024 model (290 hp and 262 lb-ft [355 Nm]). It's the addition of an electric motor to the new hybrid model where things get interesting. The hybrid Carnival uses a 1.6-L turbocharged 4-cyl. and a 54 kW motor that produce a combined 242 hp and 271 lb-ft (367 Nm). The Carnival Hybrid MPV uses a 6-speed automatic transmission. Improved fuel economy is one reason for the new hybrid option. While Kia doesn't yet have official EPA estimates, a spokesperson told SAE Media that the target is 32 mpg combined. The current ICE-only Carnival gets 22 mpg.

Blanco, Sebastian

Sea-Level Characterization of Electrically Assisted Turbocharger for Use on Aviation Diesel Engine

2024-01-1914

3/5/2024

Airborne compression-ignition engine operations differ significantly from those in ground vehicles, both in mission requirements and in operating conditions. Unique challenges exist in the aviation space, and electrification technologies originally developed for ground applications may be leveraged to address these considerations. One such technology, electrically assisted turbochargers (EATs), have the potential to address the following: increase the maximum system power output, directly control intake manifold air pressure, and reignite the engine at altitude conditions in the event of an engine flame-out. Sea-level experiments were carried out on a two-liter, four-cylinder compression-ignition engine with a commercial-off-the-shelf EAT that replaced the original turbocharger. The objective of these experiments was to demonstrate the technology, assess the performance, and evaluate control methods at sea level prior to altitude experimentation. This work covers the baseline characterization of the EAT as a turbocharger, on-engine EAT electrical operation for boost control, and a demonstration of system power extension capabilities. The baseline characterization quantified the aerodynamic performance of the EAT through the engine power curve. Then, the motor-generator on the EAT was used to directly control the intake manifold pressure. During this operation, the EAT recovered 2.4% of the exhaust energy as electrical power at the maximum nominal engine power condition. During the power extension demonstration, the manifold pressure and fueling was increased simultaneously to maintain a constant equivalence ratio. This resulted in a 6% increase engine mechanical power output and an increase in total system power output (electrical power plus mechanical power) of approximately 9%. Examples for potential on-aircraft configurations and recommendations for altitude experimentation are also expressed.

Pope, Aaron, Kim, Kenneth, Schroen, Erik, Clerkin, Peter, Musser, Marshall, Mattson, Jonathan, Meininger, Rik, Gibson, Joseph, Kang, Sang-Guk, Kruger, Kurt, Hepp, Kyle, Kweon, Chol-Bum

Effect of Turbine Speed Parameter on Exhaust Pulse Energy Matching of an Asymmetric Twin-Scroll Turbocharged Heavy-Duty Engine

02-17-02-0010

3/4/2024

The two-branch exhaust of an asymmetric twin-scroll turbocharged engine are asymmetrically and periodically complicated, which has great impact on turbine matching. In this article, a matching effect of turbine speed parameter on asymmetric twin-scroll turbines based on the exhaust pulse energy weight distribution of a heavy-duty diesel engine was introduced. First, it was built as an asymmetric twin-scroll turbine matching based on exhaust pulse energy distribution. Then, by comparing the average matching point and energy matching points on the corresponding turbine performance map, it is revealed that the turbine speed parameter of energy matching points was a significant deviation from the turbine speed parameter under peak efficiency, which leads to the actual turbine operating efficiency lower than the optimal state. In addition, a turbine speed parameter adjustment strategy was proposed by changing compressor impeller diameters to reveal the effect on turbine matching based on pulse energy weight. The testing results indicated that adjusting the impeller diameter could change the turbine speed parameter effectively. The matching aim is to make the turbine speed parameter close to the one under peak efficiency by changing impeller diameters. At last, this strategy was tested on a 12.5 L engine with EGR. The results showed that a more suitable turbine speed parameter could increase the turbine operating efficiency and the fuel economy by about 2% and 1%, respectively, at engine critical running region under the condition of maintaining the same NOx emissions.

Jin, Jianjiao, Zhang, Chenyun, Wu, Liangqin, Zhu, Hongping, Qian, Yuanping

Items per page:

1 – 50 of 1285