Browse Topic: Hybrid engines

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Synergistic Integration of Advanced Combustion and Air-Path Technologies to Maximize ICE Efficiency in Hybrid Applications2026-01-0733To be published on 07/01/2026
This work investigates the efficiency potential of reciprocating internal combustion engines (ICE) for light-duty vehicle propulsion within the current state of the art and a five-year technological horizon. A validated one-dimensional engine model was extended to integrate multiple advanced technologies, including active prechambers for ultra-lean gasoline combustion, thermal coating, an electric turbocharger capable of supplementary turbine work recovery, variable compression ratio, and variable valve timing implementing a Miller cycle. These enhancements are systematically evaluated to explore their individual and combined effects on engine performance and efficiency. Parametric studies quantify the influence of heat transfer, air–fuel ratio, compression ratio, and other key variables on engine output, enabling the generation of enhanced engine performance maps. These maps reflect synergistic interactions between parameter sets and serve as predictive tools for assessing optimized
Pla, Benjamin, Dolz, Vicente, Serrano, Jose R., Gómez-Vilanova, Alejandro, Oliva, Fermin, Cardenas, Maria, Ariztegui, Javier
NVH Design and Refinement of Dedicated Hybrid Engine on Range Extender Electric Vehicle2026-01-0688To be published on 06/20/2026
Traditional NVH (Noise, Vibration, Harshness) refinement is reactive, addressing issues post-prototype. In contrast, this work establishes NVH as the primary driver in early engine development for range extender electric vehicles (REEVs). Customer demands for imperceptible engine operation [1] - intensified by absent masking noise in electrified powertrains [2] - necessitate a proactive methodology: Usage-Driven Operating Profile: Analysis of >500,000 km fleet driving data identified statistically dominant operating conditions. This enables precise NVH focus areas and proactive avoidance-zone definition in the engine operational map. Vehicle-Driven Target Setting: Subsystem-level NVH targets (e.g., <58 dB(A) idle noise → engine-level) were rigorously derived from vehicle imperceptibility requirements and the dominant usage profile. Preventive Design Optimization: Architectural choices (stiffness-enhanced bedplate block), component tuning (crankshaft/flywheel dynamics), and subsystem
Wang, Hao, Zhang, Guiqiang
AI Based Energy Sustained Series Hybrid Aircraft2026-26-07766/1/2026
This paper investigates the energy consumption characteristics of series hybrid aircraft with a focus on comparing conventional energy management approaches against an AI-powered optimization framework. The study comprehensively models the energy demands of a series hybrid aircraft across all major flight phases, including Idle & Ground Operations, Taxi, Takeoff, Climb, Cruise, Descent, Approach, Landing, and Rollout & Taxi. For each phase, detailed mathematical formulations are developed to capture power requirements and energy flow, incorporating real-time operational parameters to enhance the accuracy of the energy consumption estimations measured in kilowatt-hours (kWh). The AI-based optimization leverages advanced control strategies, specifically Model Predictive Control (MPC) and Reinforcement Learning (RL) algorithms, to dynamically manage the aircraft’s energy systems. MPC is employed to predict and optimize future energy usage by solving constrained optimization problems over
Kanchagar, Amogha
Multi-Physics Modeling of Aircraft Hybrid Propulsion Systems Integrating Batteries, SOFC, and Jet Engine2026-99-17035/22/2026
This paper presents a multi-physics modeling approach for a hybrid propulsion system designed for High-Altitude Long-Endurance Unmanned Aerial Vehicles (HALE UAVs), integrating solid oxide fuel cells (SOFCs), lithium-ion batteries, and a jet engine. A dynamic model was developed to analyze the coupled characteristics of pressure, temperature, and power under steady-state conditions. Simulation results demonstrate that the internally integrated system achieves efficient fuel and waste heat recovery, delivering a net power output of 300–700 kW, sufficient to meet the operational demands of HALE UAVs. Key innovations include a heat exchanger maintaining SOFC stack inlet temperatures above 850 K for optimal performance and a compressor-fan subsystem enhancing gas compression efficiency. Experimental validation confirmed the accuracy of the SOFC model, with simulated electrical characteristics aligning closely with empirical data. The proposed hybrid system addresses limitations in specific
Zhang, Lin, Zhang, Di, Zhao, Lulu, Li, Xi
Optimization of Combustion Stability and Fuel Economy for Dedicated Hybrid Engines with High Exhaust Gas Recirculation Rate03-19-02-00082/26/2026
In recent years, the rapid growth of hybrid vehicles has driven the development of dedicated hybrid engines (DHEs) as a key powertrain technology for achieving high thermal efficiency and low emissions. Driven by stringent emissions regulations and demand for improved fuel economy, enhancing thermal efficiency in gasoline engines remains a critical industry challenge. Exhaust gas recirculation (EGR) technology dilutes oxygen in the intake charge, suppresses knock, and optimizes combustion phasing. However, excessive EGR rates compromise combustion stability by inducing elevated cyclic variability and potential misfire, posing challenges in maintaining stable combustion and improving fuel efficiency at high EGR levels. Thus, combustion stability and fuel efficiency optimization in Geely’s DHEs under high EGR conditions was investigated in this article. In this study, a high tumble combustion system was designed to enhance charge motion and promote stable flame propagation. Furthermore
Li, Qiang, Deng, Xiaorong, Ren, Siming, Zhang, Peiyi, Zhu, Yunfeng, Li, Hongzhou, Yan, Pingtao, Gu, Xiangsheng
TOC99-08-01-0TOC2/11/2026
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Tobolski, Sue
Equivalent Power Consumption Minimization Strategy Based Controller for a Novel Dedicated Hybrid Engine Powertrain for a Light-Duty Application2025-01-041610/7/2025
Due to strengthened CO2 regulations, the automotive industry is facing the challenge of reducing greenhouse gas emissions. In response, the industry has focused on developing various technologies that enhance fuel economy and reduce greenhouse gas emissions. Hybrid electric powertrains have demonstrated significant potential to improve fuel economy and reduce greenhouse gas emissions. The improvements resulting from hybrid electric powertrains depend on the degree of electrification, which is closely related to the sizing of the motor and battery. However, hybridization increases the complexity of the powertrain. As multiple power sources are involved, complex control algorithms must be developed to allocate power usage among various driving scenarios while fulfilling driver requests. One way to simplify hybrid power management control is to implement optimization strategies that determine the operating states for each component during different driving scenarios, aiming to minimize
Echeverri Marquez, Manuel, Bhoge, Mahesh, Lago, Rafael, Engineer, Nayan, Bhadra, Kaustav, Whitney, Christopher, Baur, Andrew
Methanol Cold Start Procedure for a Serial Hybrid Powertrain2025-24-00749/7/2025
Methanol obtained from regenerative sources is a renewable fuel with many advantages when used in a spark ignition combustion process. Methanol has a comparatively high enthalpy of vaporization, leading to lower combustion temperatures (compared to gasoline combustion) and, hence, lower wall heat losses as well as a reduced tendency to autoignition. Several cold start methods were examined for this paper. In a serial hybrid powertrain with one internal combustion engine, ICE, and one electric machine, the load demand of the ICE can be controlled for best efficiency. The ICE is operated on liquid renewable fuel, which provides a high volumetric and gravimetric power density, easy energy storage, delivered from a very cost effective already existing infrastructure of fuel distribution. The electric machine provides comfortable electric driving, high efficiency, locally and temporary zero emissions. The eFuel should be produced from a closed carbon cycle. Methanol is a challenging fuel
Dobberkau, Maximilian, Werner, Ronny, Atzler, Frank
On a NMPC-Based Supervisory Control Logic for Energy Management Purposes in Aeronautical Hybrid Propulsion Systems2025-24-01029/7/2025
Eco-sustainability is one of the main aspects focused on motor industries, including those related to air transport, which work to realize alternative propulsion systems, such as Hybrid Electric Propulsion Systems, for reducing CO2 emissions. Despite the minor CO2 emission produced by Hybrid Electric Propulsion Systems, these categories of propulsors require a proper control architecture for managing combustion and electric energies based on driver decisions and the flight mission set. A supervisory control logic, based on a Nonlinear Model Predictive Control (NMPC), is presented in this work to guarantee a specific State of Charge level of batteries coupled with the minimization of fuel consumption of an aeronautical Hybrid Propulsion System. These two goals are achieved by the designed NMPC, which provides the best amount of torque between the propulsors belonging to the analysed aeronautical powertrain, consisting of an Internal Combustion Engine and an Electric Machine. The
Tordela, Ciro, Fornaro, Enrico
Data-Driven Modeling of H2-SCR Catalysts for Real-Time Estimation of NOx Reduction Efficiency2025-24-00849/7/2025
Achieving zero emissions across transportation is a tremendous challenge. The upcoming Euro 7/VII standards, set to be enforced in 2025, will mandate further reduction in ICEs exhaust emissions. Thus, additional improvements and potential new technologies and fuels are needed to design ultra-low emissions vehicles. Hydrogen seems to be a very attractive fuel, thanks to its high lower heating value, clean combustion, and extremely low pollutant emissions, due to the zero-carbon content. Nevertheless, NOx emissions are still an issue in hydrogen fueled engines and optimized lean-burn combustion and suitable after-treatment NOx reduction are mandatory to reach high specific power and efficiency and near zero NOx emissions, thus enabling H2-ICE powered vehicles to be zero-impact emitting technology solution. Selective Catalytic Reduction by using NH3 as the reducing agent is the most effective control technology for NOx abatement. Nevertheless, ongoing research and innovation are critical
Crispi, Maria Rosaria, Conde Cortabitarte, Carla, Occhicone, Alessio, Piqueras, Pedro, Arsie, Ivan, Pianese, Cesare
Energy-Efficient Range-Extender Study for Commercial Vehicle Electrification with Renewable Fuels02-19-01-00048/9/2025
Light-duty vehicles (LDV) are scaling up electrification technologies from battery to dedicated hybrid engines (DHEs). The success from electrification of LDVs can be a starting point to look into a similar trending development of commercial vehicles (CV), which are bigger and heavier with more demanding work cycles. “Greenhouse Gas Emissions Standards for Heavy-Duty Vehicles (HDV)—Phase 3” establishes new CO2 emission standards for MY 2032 (Model Year) and later HD vehicles with more stringent CO2 standards phasing in as early as MY 2027 for certain vehicle categories. In this article, the focus is about improving the operational efficiency of MDHD (medium-duty and heavy-duty) vehicles through a selected electrification technology in this study rather than pure BET (battery electric truck). Extended-range electric vehicle (EREVs) systems are studied here to address sustainability regarding charging infrastructure and by using the renewable fuels (hydrogen, ammonia, methanol, and
Wang, Hailong, Ma, Tiancai, Shuai, Shijin, Wang, Zihui, Song, Xubin
Applied Full-Bridge Micro Strain Gauge to High Pressure Sensor for Gasoline Direct Injection/Hybrid System2025-01-02206/16/2025
High Pressure Sensors (HPS) are essential for internal combustion engines and hybrid engine systems. High pressure sensor measures the pressure in the Delivery fuel rail Pipe Module (DPM) to allow the Engine Control Unit (ECU) to control the high pressure pump to generate the required fuel pressure. Most high pressure sensors measure the displacement of the metal-diaphragm according to pressure, and are mainly composed of Half-bridge type Micro Electro Mechanical System (MEMS) elements of the piezo-resistive method. This time, we would like to introduce a high pressure sensor that uses a Full-bridge type MEMS structure. This is cheaper than the existing one and can provide higher performance with reliability. However, there are disadvantages of the full-bridge type applied to high pressure sensors. Unlike the Half-bridge method that measures displacement over a wide area, it measures displacement over a narrow area, so it has the disadvantage of weak to external noise due to increased
Lim, SeungGu, Lee, DongYoung, Kim, JungTaek, Shin, MoonSung
Optimal Onboard Battery Charging Strategy for Hotel Load Management in Mild-Hybrid Heavy-Duty Truck02-18-03-00176/12/2025
Heavy-duty trucks idling during the hotel period consume millions of gallons of diesel/fuel a year, negatively impacting the economy and environment. To avoid engine idling during the hotel period, the heating, ventilation, and air-conditioning (HVAC) and auxiliary loads are supplied by a 48 V onboard battery pack. The onboard battery pack is charged during the drive phase of a composite drive cycle, which comprises both drive and hotel phases, using the transmission-mounted electric machine (EM) and battery system. This is accomplished by recapturing energy from the wheels and supplementing it with energy from the engine when wheel energy alone is insufficient to achieve the desired battery state of charge (SOC). This onboard battery pack is charged using the transmission-mounted EM and battery system during the drive phase of a composite drive cycle (i.e., drive phase and hotel phase). This is achieved by recapturing wheel energy and energy from the engine when the wheel energy is
Huang, Ying, Hanif, Athar, Ahmed, Qadeer
Infrastructure Design Criteria for Accommodating Hydrogen Electric Vertical and Takeoff Landing (H 2 eVTOL) Aircraft Technologies at VertiportsF-0081-2025-03865/20/2025
Hydrogen-electric vertical takeoff and landing (H2eVTOL) (or fuel cell-electric VTOL) aircraft technologies are poised to emerge in the next coming decades and start operating from existing heliports and new vertiports. This paper assesses how key H2eVTOL design features interact with the ground infrastructure and how facility designers can address H2eVTOL specific facility requirements–especially the supply of hydrogen to the aircraft. Vertiport design should maximize compatibility are important to facilitate the accommodation of hydrogen technologies, minimize the need for extensive capital investments, and promote safety and operational efficiency. Considerations should be given to factors such as general aircraft configuration, electric and hybrid propulsion systems, and refueling infrastructure. The definition of notional aircraft concepts representing the evolution of critical VTOL aircraft over the next coming decades can help aviation facility planners and designers understand
Le Bris, Gaël, Nguyen, Loup-Giang
Optimization of HEV Vehicle’s Engine Modulated Noise2025-01-00845/5/2025
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
Dan, Kong
Integrating for Safety – A Proposed Approach to the Integration of Propulsion Battery Systems in Hybrid Electric Aviation2025-01-01485/2/2025
The authors have witnessed a notable surge in the number of designs and in the guidance material for electric and hybrid aircraft. FAA and EASA have continued to evaluate the safety of Propulsion Battery Systems (PBS), with a focus on thermal runaway containment testing. As a result, a harmonization white paper [7] was issued to provide a certification path for Thermal Runaway (TR) Hazards, followed by an EASA certification memorandum on the acceptable approaches for the certification of Electric/Hybrid Propulsion Systems (EHPS). Recently, an FAA Advisory Circular (draft) was issued for the “powered-lift” aircraft that feature these propulsion battery systems. Despite the advances made by electric/hybrid aircraft manufacturers and the aviation authorities, there is still a missing piece of the puzzle. Mainly, engineering work still needs to be done to properly integrate the EHPS architecture to achieve safety objectives. The burden is still on systems engineering to propose their own
Hanna, Michael, Walker, Cherizar
High-Efficient and Cost-Effective Three-Way Catalyst Substrate Design for Plug-in Hybrid Electric Vehicle2025-01-85284/1/2025
China 6b regulation was fully implemented since July 2023 with very strict emission standards for HC, NMHC, NOx, and CO. The country is now also in the process of developing China 7 regulation, which will perhaps impose even stricter emission limits and extra criteria pollutants including NH3. Moreover, increasingly strict fuel consumption regulation has been implemented as well and it is highly possible that greenhouse gas emission limits will be included in the China 7 regulation. With the hybrid technology innovation, PHEVs are effective in fuel economy and emission reduction, which are favored by manufacturers and consumers, and leading to a rapid increase in market share. Through the optimization of hybrid architecture and the synergy of electric motors, the operating conditions of the hybrid engine have been optimized, making it more stable and avoiding extreme engine operating conditions compared to traditional ICE, which also provides possibilities for optimizing the after
Wang, Jiming, Li, Chunbo, Feng, Xiangyu, Chen, Xiaolang, Boger, Thorsten, Tian, Lichen, Hu, Xianli, Zeng, Jun, Tian, Tian, Gao, Bojun, Li, Dacheng, Liu, Shicheng, Jiang, Fajun
Experimental Investigation of Hydrogen or Methane Injection in Active Pre-Chamber on a Lean Combustion Gasoline Engine2025-01-71061/31/2025
With the global promotion of carbon neutrality policies, internal combustion engine (ICE) of traditional fossil fuel is gradually transitioning to carbon neutral fuel ICE, and hybrid dedicated engines are gradually replacing traditional internal combustion engines in the passenger car market. Ultra-lean combustion supported by active pre-chamber is one of the key technologies for achieving high thermal efficient over 45% BTE. However, there are still issues like cold start and PN emissions caused by impingement of liquid fuel injection in pre-chamber, and there is still room for improvement in thermal efficiency by less energy of pilot ignition fuel. Gaseous fuel such as hydrogen or methane have no wetting issues, and can be more easily controlled in terms of the injection amount in pre-chamber, thereby using a less amount of gaseous fuel as the pilot ignition fuel could be a solution. Due to the above situation, this article conducted experiments on a lean burn gasoline engine by
Liu, Yaodong, Liu, Mingli, He, Zhentao, Li, Xian, Zhao, Chuan, Qian, Dingchao, Qu, Hanshi, Li, Jincheng
Study of Soot Generation in Hybrid Engines during Cold Start and Low-Load Conditions Using an Optical Engine2025-01-70471/31/2025
As regulations regarding vehicle emissions and fuel consumption become increasingly stringent, the development of hybrid power systems is accelerating, primarily due to their benefits in fuel efficiency and reduction of pollutants. Hybrid engines are specially designed to operate optimally at mid to high speeds and loads. But for low-speed low-load conditions, due to the relatively low in-cylinder tumble intensity and lower injection pressure, the fuel-air mixture tends to deteriorate, resulting in an increase in particle number. To enable the engine to reach optimal RPM and load quickly during frequent start-stop cycles, hybrid engines typically set a higher startup engine speed and establish fuel rail pressure more quickly compared to traditional engines. Yet hybrid engines still encounter challenges of soot generation during cold start conditions. Especially in urban driving conditions where the hybrid engine frequently experiences startups and idling, the soot generation problem
Liu, Changye, Man, Xingjia, Cui, Mingli, Liang, Yuanfei, Wang, Shangning, Li, Xuesong
Impact on FEAD Dynamic Performance of Mild Hybrid Engine with Increase in Engine Torque2024-28-020412/5/2024
Front End Accessory Drive (FEAD) systems are used in automobiles to transfer power from the engine-to-engine accessory components such as the alternator, water pump, etc. using a Belt and Tensioner. The emergence of Mild hybrid technologies has led to the replacement of alternator with Belt-driven Integrated Starter-generator (B-ISG). In conventional configuration of FEAD, the power transfer is in single direction but in mild hybrid engine power transfer is bidirectional: tight and slack side of the Belt changes as per Torque assist or Regeneration mode. The presence of an integrated starter-generator (ISG) in a belt transmission places excessive strain on the FEAD System and necessitates checking the dynamic performance of FEAD System thoroughly. Study of Increase in Engine Torque in existing Vehicle was done to understand its effect on various system. This vehicle is Mild Hybrid and consists of Belt-driven Integrated Starter generator system. Increase in Engine torque lead to
Kumar, Aditya, Gupta, Avinash, Bharti, Anil Kant
New 1.5-Liter Hybrid Engine Development with High Brake Thermal Efficiency2024-01-510711/29/2024
The hybrid engines produced by most original equipment manufacturers (OEMs) have been modified to fit within the framework of conventional engine designs. Recently, Geely has introduced a new 1.5-liter (1.5L) inline four-cylinder (I4) TGDI engine, specifically designed to meet the requirements of its innovative, efficient, and intelligent hybrid powertrain architecture. This engine achieves an impressive brake thermal efficiency (BTE) of 44%, as well as high specific torque at 153 Nm/L and high specific power at 67 kW/L. To attain this superior performance, the following technical strategies were implemented: a high compression ratio, the robust Miller cycle, an extended piston stroke-to-bore ratio, an intake port optimized for high tumble, cooled exhaust gas recirculation (EGR), and an advanced high-energy ignition system. Among these, the middle four strategies, in conjunction with piston cooling jets and enhanced exhaust-side cooling, all contribute to improved in-cylinder
Li, Qiang, Liu, Yang, Zhang, Peiyi, Yan, Pingtao, Li, Hongzhou, Zhu, Yunfeng, Ji, Yan, Li, Minggui, Cui, Boyue
Dynamics of a Variable Speed Hybrid-Electric Helicopter Propulsion SystemF-0080-2024-12525/7/2024
In this paper, a comprehensive dynamic simulation of a parallel hybrid gas-electric single main rotor helicopter involving a motor/generator (MG) pair and a differential planetary gear transmission (PGT) arrangement forming an electronic continuously variable transmission (E-CVT) was performed. This notional hybrid electric helicopter was sized based on a retrofit of a dual engine, 10000 lb, 2500 Hp class helicopter. The total weight added by the electric components was 182 lbs which increased the propulsion system weight from 1184 to 1366 lbs. The simulation results found that at 110 kts cruise, the hybrid electric system enabled a 27% reduction in main rotor rpm which resulted in an 18% reduction in the fuel burn rate. It is concluded that use of an E-CVT parallel hybrid propulsion system offers potential for increased flight range and reduced fuel consumption in medium to large-scale helicopter applications.
DeSmidt, Hans, Ai, Zhisheng
Thermal Management Development for a Dedicated Hybrid Engine2024-01-24164/9/2024
The high-efficiency dedicated hybrid engine (DHE) has led to increasingly complex challenges in engine thermal management. On one hand, the high compression ratio of up to 16:1 makes the engine more susceptible to knocking, necessitating meticulous thermal management to mitigate the potential sensitivity to metal temperature. On the other hand, extensive use of external cooled exhaust gas recirculation (EGR) helps reduce knocking and improve thermal efficiency, but it also raises temperature levels and requires additional cooling measures. For the 1.5L DHE developed by SAIC Motor, a split cooling structure was employed in the engine cooling system design, with the cylinder head water jacket and cylinder block water jacket arranged in parallel and equipped with different coolant outlets. By utilizing a dual thermostat to control flow, this design allows for adjustable flow distribution, providing effective cooling to the cylinder head while reducing cooling to the cylinder block. The
Xu, Zheng, Xia, QiWei, Peng, Chao, wang, YanJun
Combustion Development and Efficiency Improvement for Hybrid Engines2024-01-20934/9/2024
In the pursuit of carbon emission reduction, hybridization has emerged as a significant trend in powertrain electrification. As a crucial aspect of hybrid powertrain system development, achieving high brake thermal efficiency (BTE) and a wide operating range with high efficiency are essential for hybrid engines to effectively integrate with the hybrid system. When developing dedicated hybrid engines (DHE), several design considerations come into play. First, in order to make efficient use of available resources and enable engine production on the same assembly line as conventional engines, it is crucial to maintain consistency in key design parameters of the cylinder head and block, thus extending the platform-based design approach. Among the key measures to achieve high BTE, cooled exhaust gas recirculation (EGR) has been extensively explored and proven effective in improving efficiency by mitigating knocking and reducing engine cooling heat loss. Fast combustion, acting as a
Xu, Zheng, Qiu, Jie, Zhang, ZiQing, Cheng, Chuanhui, Zhang, YaJun, Yang, Yang, Wang, Yingzhen, Lu, Yuan, Zhou, Zhou, Li, XiaoYang
Simulation Investigation of Turbulent Jet Ignition (TJI) Combustion in a Dedicated Hybrid Engine under Stoichiometric Condition2024-01-21114/9/2024
Turbulent jet ignition (TJI) combustion using pre-chamber ignition can accelerate the combustion speed in the cylinder and has garnered growing interest in recent years. However, it is complicated for the optimization of the pre-chamber structure and combustion system. This study investigated the effects of the pre-chamber structure and the intake ports on the combustion characteristics of a gasoline engine through CFD simulation. Spark ignition (SI) combustion simulation was also conducted for comparison. The results showed that the design of the pre-chamber that causes the jet flame colliding with walls severely worsen the combustion, increasing the knocking intendency, and decrease the thermal efficiency. Compared with SI combustion mode, the TJI combustion mode has the higher heat transfer loss and lower unburned loss. The well-optimized pre-chamber can accelerate the flame propagation with knock suppression. Strong-tumble flow distorts the jet flame propagation, which is not
Liu, Shang, Lin, Zhelong, Qi, Yunliang, Lu, Guoxiang, Wang, Bo, Liu, Yang, Wang, Zhi
Aspects of Engine Lubricant Operating Conditions and Fuel Economy Differentiation; In-Vehicle Comparisons of Standard Internal Combustion Engine with Two Types of Hybrid Electric2024-01-28244/9/2024
Due to the global drive for carbon neutrality, passenger vehicle gasoline engines are transitioning to higher levels of electrification, such as hybrid electric vehicles and plug-in hybrid electric vehicles, HEVs and PHEVs. Compared with conventional internal combustion engine (ICE) vehicles, the HEV or PHEV engine whilst in ICE only operation, typically operates for multiple shorter periods, in turn the engine coolant and lubricant temperatures are lower. Conventional internal combustion engines are often able to yield valuable fuel economy benefits by selecting appropriate engine lubricating oils, typically employing reduced viscosity and suitable additives. There are commercial engine tests available for measurement, often in an engine test cell for precision. Steady state testing is also a simplified option. Such efforts require care, as the accurate measurement is technically and practically challenging. This level of difficulty is again increased by the further complication of
Butcher, Richard, Bradley, Nathan, Jamieson, Matthew, Chambers, Thomas
High-Precision Modeling and Online Validation of a 200kW-Class Series Hybrid Power System in Aviation2023-01-709712/31/2023
Taking into account the high rotor speed of the generator and the trend of high voltage in direct current microgrids in high-power aviation hybrid propulsion systems, a hybrid power system with a power of 200 kilowatts (kW), a voltage of 540 volts (V), and a rated generator speed of 10500 r/min was established. Anticipating the demands of future high-power system tests, a matching simulation model was developed. The paper discusses various aspects including model construction, test design, and result validation, proposing an overall control strategy for series hybrid aviation propulsion systems – utilizing lithium-ion batteries to stabilize grid voltage and using the turboshaft-generator unit as the primary power source to meet the main power demands of the electric propulsion system. The established model consists of four modules: turboshaft engine, power generator, voltage-stabilizing battery, and electric motor/propeller. These modules are independently controlled and are unified
Diao, Bo, Li, Po, Zhu, Jianfeng, Huang, Guochen, She, Yunfeng, Xing, Yaoren
Simulation Study on High Expansion Ratio Dedicated Hybrid Engine for Hybrid Commercial Vehicle Application2023-01-700510/30/2023
The fuel economy and emission of the hybrid vehicle depend largely on the selected engine. And the dedicated hybrid engine (DHE) can be controlled to operate in the optimal operating range because DHE can be decoupled from the vehicle transmission system. The main purpose of this paper is to improve the thermal efficiency of the diesel engine under common operating conditions combined with high compression ratio (CR) and early or late intake valve closing (IVC) angle. According to the vehicle road spectrum data, the optimal operating range of the engine is determined to be 1200-1400 rpm and 70%-90% load. Then CR and IVC angle are optimized by using the calibrated one-dimensional thermodynamic model of the engine under limited peak combustion pressure (Pmax). The results show that the adjustment of IVC angle and CR can control the thermal state at the end of compression stroke. The combination of CR and IVC angle can achieve the optimal fuel consumption improvement. The minimum brake
Wang, Xiaosa, Lin, Zhiqiang, Wang, Hu, He, Hua, Wang, Xiaohui, Liang, Depu
An Experimental Study on Soot Particles Size Distribution and Nanostructure Evolution at Different Tailpipe Positions of a Dedicated Hybrid Engine2023-01-700310/30/2023
Hybrid vehicles, compared to pure fossil fuel vehicles, have added power battery pack, high-power electric motors. The space of the aftertreatment is limited, so the layout position of the aftertreatment system must be optimized. Meanwhile, the European 7 emission standard reduces the particulate number (PN) limit particles size from 23nm to 10nm, presenting new challenges for the aftertreatment system. The focus of this study is to investigate the variations in particles size distribution and nanostructure of soot particles during the exhaust along a dedicated hybrid engine aftertreatment system (catalyst carrier free). Four operating conditions were selected for the test, namely 2000 r/min-0.2 MPa, 2000 r/min-0.8 MPa, 4500 r/min-0.2 MPa, and 4500 r/min-0.8 MPa. The particles sampling points are before Three-way catalyst (TWC), after TWC, and after gasoline particulate filter (GPF). Engine Exhaust Particle Sizer (EEPS) was used to analyze the changes in particle modal distribution
Fu, Jiale, Hu, Zhiyuan, Fang, Liang, Lou, Diming, Tan, Piqiang, Yin, Qi
Hybrid Operation Characteristics and Their Impact on Engine Oil Requirements2023-32-01729/29/2023
With the increasing regulatory stringency on emission reduction and efficiency improvement, the automotive industry has experienced a significant shift in the hardware platform. Among technology candidates, hybrid technology is still considered one of the most viable approaches to meet the regulation requirement (both emission and efficiency) at an affordable cost to both the customer and the manufacturer. New engine operating characteristics are expected in hybrid applications which would potentially result in different performance requirements for the engine oil. Therefore, it is crucial to understand those characteristics of a hybrid powertrain, from which the insights of fluid requirements can be derived. A hybrid vehicle test study was conducted to evaluate the engine operation of different kinds of hybrid platforms. The hybrid operation has been well characterized by thoroughly analyzing parameters on each engine. The temperature profile from each hybrid powertrain was evaluated
Garelick, Kenneth, Shao, Huifang, Hidetaka, Hoshino, Li, Yanfei, Shuai, Shijin
2024 Toyota Land Cruiser returning to its roots23AUTP09_139/1/2023
After three years away from the U.S. market with its range-topping SUV, the Land Cruiser, Toyota unveiled the redesigned 2024 Land Cruiser in Salt Lake City on Aug. 1. The model, long known around the world for its durability and offroad credentials, arrives with the SUV competition hotter than ever. The company said the new model will start at around $55,000. The new Land Cruiser has just one engine option, the i-Force Max turbo 2.4-L four-cylinder hybrid that generates 326 hp and 465 lb-ft (630 Nm) that is routed through an 8-speed automatic transmission. All models are equipped with what Toyota classifies as a “full-time four-wheel-drive system” with a lockable center differential and an electronically controlled 2-speed transfer case to impart high- and low-range capability. Also standard is a lockable rear differential to apportion power in a 50/50 ratio across the rear axle.
Clonts, Chris
Modeling and Experimental Validation of a Hybrid Electric Propulsion System for Naval Applications2023-24-01318/28/2023
Focusing on coastal or inland navigation cities, where emissions from ships are not negligible concerning global ones, the possibility of reducing exhaust gas pollution would have more benefits for public health and air quality. Therefore, in recent years, increasing attention on environmental sustainability is driving the shipbuilding industry towards greener propulsion based on full-electric or hybrid-electric propulsion systems. This work is presented a parallel hybrid system composed of two electric motors, one internal combustion engine, and lithium battery storage. All motors are coupled to the propeller through a specially designed transmission system based on the High Sliding Gear theory (HSG). The hybrid-electric propulsion system is designed to extender the battery pack durability, ensuring a smooth profile of the required current, through the complementary action of the batteries and the internal combustion engine. Then, the overall performance of the hybrid propulsion
Marialto, Renato, Brando, Gianluca, Dannier, Adolfo, Sementa, Paolo, Cardone, Massimo, Fornaro, Enrico
An Energy Management Strategy for Aeronautical Hybrid Propulsion Systems Based on an MPC Supervisor2023-24-00268/28/2023
In the last decades, the requirement related to the reduction of energy waste has been focused on the aeronautical field for decreasing CO2 emissions in propulsion systems, coupled with the possibility of improving their ecological sustainability. Performance of hybrid electric aircraft are affected by the sizes and weights of propulsion systems typically constituted of internal combustion engines and electric motors. Therefore, the correct design of propulsive architectures is fundamental to ensure a desired state of charge target level of batteries compliant with the flight plan provided by a driver unit. A Linear Time Variant Model Predictive Control (LTV-MPC) strategy for energy management purposes of an aeronautical hybrid powertrain is proposed in the present work. The MPC, designed as a supervisor, provides the best trade-off between command torques of motors belonging to a parallel-hybrid propulsion system to guarantee the final state of charge as close as possible to the
Fornaro, Enrico, Tordela, Ciro
An MPC-Based Strategy for Managing Energy in Hybrid Powertrains of Fast Boats2023-24-00258/28/2023
In the shipbuilding industry, the employment of hybrid propulsion systems is increasingly common on-board vessels for making more eco-sustainable boat traffic in marine waters. Energy management systems are required to ensure the culling of fuel consumption and the preservation of batteries by monitoring their state of charge in hybrid powertrains, coupled with the possibility of performing the sea path desired by a driver unit. A Model Predictive Control (MPC) supervisor is proposed in the present work for managing a marine parallel-hybrid propulsion system in terms of handling the state of charge of batteries and the driving cycle imposed by the boat driver. Specifically, the MPC is employed to avoid excessive electric energy consumption observable as a reduced loss in terms of the state of charge of batteries by selecting the best amount of command torques related to two electric motors and one internal combustion engine of the considered powertrain. A lumped parameters model of a
Tordela, Ciro, Fornaro, Enrico
Energy Management System of Fuel Cell Electric Vehicles Based on Stochastic Model Predictive Control and Markov Chains2023-24-00248/28/2023
In the mobility industry, Fuel Cell Electric Vehicle (FCEV) combines fuel cell technology with batteries, allowing to overcome some limitations of Battery Electric Vehicles (BEVs), such as the high recharging time and the high battery mass for applications requiring a high amount of energy (e.g., bus and heavy-duty vehicles). FCEVs have the possibility to collect several information from Intelligent Transportation Systems (ITSs) with relevant potential for vehicle efficiency improvement. Indeed, an online vehicle speed prediction inherently considering real-life factors such as traffic flow, driving path and driving style, allows for novel designs of Energy Management Systems (EMSs) for the optimal operations of the hybrid propulsion system. In such context, this paper proposes an EMS based on Stochastic Model Predictive Control with Learning (SMPCL) to optimize the hydrogen consumption of a Fuel Cell Electric Vehicle (FCEV), while guaranteeing the fulfillment of constraints on battery
Alfieri, Vincenzo, Binetti, Giulio, Ruotolo, Romualdo, Gandino, Edoardo
Analyzing the Usage of Wankel Engine Technology in Future Automotive Powertrains13-05-02-00098/4/2023
The Wankel engine is an eccentric rotary internal combustion engine known for its simplicity, compactness, reliability, and efficiency. However, issues related to sealing, efficiency, and emissions have hindered its widespread use. Recent advancements in sealing technology, novel designs, material coatings, and alternative fuels have addressed some of these problems, leading to improvements in Wankel engine performance. This study examines these advancements in Wankel engine technology and proposes three potential applications for future automotive use. The first application involves utilizing a Wankel engine with a continuously variable transmission to replace the powertrain in conventional vehicles. The second application suggests replacing the engine in a series-parallel electric-hybrid architecture with a Wankel engine. Lastly, the third application explores using a Wankel engine as a range extender for electric vehicles. To evaluate the benefits in terms of fuel consumption for
Mittal, Vikram, Shah, Rajesh, Przyborowski, Alexandra
Increasing Engine Efficiency with Hydrogen Assisted Lean Burn Operation on a Small Bore, Long Stroke DISI Engine2023-01-02464/11/2023
Internal combustion engines fall under increased environmental and social pressure. However, they will still play an important role in future transport, especially in hybrid propulsion systems. As a consequence, efficiency of SI engines has to be further increased. Lean burn operation provides a promising way to reach this target. An extremely downsized SI single cylinder research engine is used for the investigations. The engine features a stroke-to-bore ratio of 1.5, leading to higher piston speeds and hence increased tumble motion. The resulting increase in turbulent flame speed supports sufficient combustion performance of diluted mixtures. Although the mentioned provisions increase combustion stability for lean burn operation the reachable relative air/fuel ratio is limited. In order to extend the lean burn capabilities of the engine (λ ≥ 2.0) and further exploit the efficiency advantages of this combustion process the engine is upgraded with a hydrogen port fuel injection. With
Wenz, Erich, Eilts, Peter
Combined Physical and ANN-Based Engine Model of a Turbo-Charged DI Gasoline Engine with Variable Valve Timing2023-01-01944/11/2023
High-efficient simulations are mandatory to manage the ever-increasing complexity of automotive powertrain system and reduce development time and costs. Integrating AI methods into the development process provides an ideal solution thanks to massive increase in computational power. Based on an 1D physical engine model of a turbo-charged direct injection gasoline engine with variable valve timing (VVT), a high-performance hybrid simulation model has been developed for increasing computing performance. The newly developed model is made of a physics-based low-pressure part including intake and exhaust peripheries and a neural-network-based high-pressure part for combustion chamber calculations. For the training and validation of the combustion chamber neural networks, a data set with 10.5 million operating points was generated in a short time thanks to the parallelizable combustion chamber simulations in stand-alone mode. The data set covers wide variation ranges of boundary and operating
Wei, Jingsi, Liu, Mingjia, Angerbauer, Michael, Yang, Qirui, Xu, Hanjun, Grill, Michael, Kulzer, André, Chen, Ceyuan
Q&A23TOFHP04_174/1/2023
As part of its path to carbon neutrality, Kubota Engine engineers have developed a new 3.8-liter hydrogen engine that was introduced at CONEXPO 2023 in Las Vegas. The 4-cylinder spark-ignited engine employs port fuel-injection and provides 85 kW (114 hp), which is the output required for a 45-kVA generator, the company notes. Kotaro Shiozaki, PR manager, Industrial Engine at Kubota Corp., said that hybrid powertrains also are an effective solution for reducing CO2 from industrial engines, and he's confident they will be more than just an interim solution. Kubota displayed three hybrid solutions: a P0 micro-hybrid that will be available later this year, a P1 hybrid that provides brief periods of motor assist when high output is required and a P2 hybrid engine scheduled for production in 2025 that offers electric-motor drive.
Gehm, Ryan
ENGINE OIL PUMP PERFORMANCE AND DURABILITY TEST PROCEDURESUSCAR46 (Current)3/23/2023
SAE/USCAR-46 defines test methods and outputs for engine oil pump bench testing. Performance and durability testing are the primary focus of this standard. This is written to specifically address testing of electronically controlled variable displacement pumps but can be adapted to mechanically controlled pumps and other pump technologies as needed. This standard outlines critical inputs and outputs in order to perform the testing and report results, but does not specifically set the acceptance standards or pass/fail criteria. Acceptance criteria must be set by the customer.
USCAR
A Coupling Architecture for Remotely Validating Powertrain Assemblies14-12-02-00153/15/2023
Among the myriad of potential hybrid powertrain architectures, selecting the optimal for an application is a daunting task. Whenever available, computer models greatly assist in it. However, some aspects, such as pollutant emissions, are difficult to model, leaving no other option than to test. Validating plausible options before building the powertrain prototype has the potential of accelerating the vehicle development even more, doing so without shipping components around the world. This work concerns the design of a system to virtually couple—that is, avoiding physical contact—geographically distant test rigs in order to evaluate the components of a powertrain. In the past, methods have been attempted, either with or without assistance of mathematical models of the coupled components (observers). Existing methods are accurate only when the dynamics of the systems to couple are slow in relation to the communication delay. Also, existing methods seem to overlook the implications of
Ametller, Adria, Brace, Chris
Electric Hybrid Propulsion SystemTBMG-474972/1/2023
Allison Transmission Indianapolis, IN 317-242-5000
Development of A 1.5L High-Efficiency and High-Specific-Power Hybrid Engine2022-01-706210/28/2022
Although the brake thermal efficiency of the state-of-the-art Atkinson-cycle hybrid engines have reached 41%, such engines typically have a low specific power. The ideal hybrid engines for SUVs should have a high thermal efficiency as well as a high specific power. Jiangling Motors recently developed a 4-cylinder, 1.5L TGDI hybrid Miller engine for powering mid-size SUVs, which has achieved 42% brake thermal efficiency, 19.3-bar BMEP, and 73.3-kW/L specific power. The engine has a high compression ratio, a long stroke, and is equipped with a low-pressure EGR system. It can operate with the stoichiometric mixture on the full engine map, with the help of the water-cooled exhaust manifold and the intelligent thermal management system.
Liu, Yong, Liao, Shanbin, Zheng, Yuewei, Chen, Bin, Miao, Ruigang, Zeng, Cuiwei, Ouyang, Xianlin, Cai, Xingqi, Yang, Yanhua, Zeng, Honglian, Cao, Liming, Teng, Ho
Hybrid Propulsion SystemsTBMG-4677810/1/2022
Benchmark Space Systems Burlington, VT 678-576-6126
Realistic Steady State Performance of an Electric Turbo-Compound Engine for Hybrid Propulsion System2022-24-00159/16/2022
The efficiency of Hybrid Electric Vehicles (HEVs) may be substantially increased if the unexpanded exhaust gas energy is efficiently recovered and employed for vehicle propulsion. This can be accomplished employing a properly designed exhaust gas turbine connected to a suitable generator whose output electric energy is stored in the vehicle storage system; a new hybrid propulsion system is hence delineated, where the power delivered by the main engine is combined to the power produced by the exhaust gas turbo-generator: previous studies, carried out under some simplifying assumptions, showed potential vehicle efficiency increments up to 15% with respect to a traditional turbocharged engine. Given the power target of the required exhaust gas turbo-generator, no commercial or reference product could be considered: on account of this, in the preliminary evaluations, the turbine efficiency was assumed constant. In this paper instead the authors present the result of new evaluations
Pipitone, Emiliano, Caltabellotta, Salvatore, Beccari, Stefano, Lanzafame, Rosario, Mauro, Stefano, Brusca, Sebastian
Freevalve: Control and Optimization of Fully Variable Valvetrain-Enabled Combustion Strategies for High Performance Engines2022-01-10668/30/2022
With ever stricter legislative requirements for CO2 and other exhaust emissions, significant efforts by OEMs have launched a number of different technological strategies to meet these challenges such as Battery Electric Vehicles (BEVs). However, a multiple technology approach is needed to deliver a broad portfolio of products as battery costs and supply constraints are considerable concerns hindering mass uptake of BEVs. Therefore, further investment in Internal Combustion (IC) engine technologies to meet these targets are being considered, such as lean burn gasoline technologies alongside other high efficiency concepts such as dedicated hybrid engines. Hence, it becomes of sound reason to further embrace diversity and develop complementary technologies to assist in the transition to the next generation hybrid powertrain. One such approach is to provide increased valvetrain flexibility to afford new degrees of freedom in engine operating strategies. Freevalve is an electro-hydraulic
Elmagdoub, Abdelrahman Waleed Mohamed, Möller, Andreas, Carlson, Urban, Brace, Chris, Akehurst, Sam, Turner, James, Zhang, Nic
Architecture Examples for Electrified Propulsion AircraftAIR8678 (Current)8/1/2022
The application of electric power for aircraft propulsion can take a variety of forms, ranging from partial electric to full electric. The introduction of electric engines to drive propulsors, along with the variety of available methods to generate electricity and store energy offers great degree of new design freedom for next-generation aircraft and aircraft architectures. This newfound design freedom exposes a need within the aviation industry to establish a common design language for electrified propulsion. While this need for a common design language is recognized, the intent of this document is to encourage innovation, providing reference architectures as a launching point for future work in this area. This document will describe potential electrified propulsion architectures and provide examples. While providing these example architectures, this document will develop common definitions for the elements of the architectures by defining: 1 The elements of electrified propulsion
E-40 Electrified Propulsion Committee
Assessment of Components Sizing and Energy Management Algorithms Performance for a Parallel PHEV2022-37-00156/14/2022
In Plug in hybrid electric vehicles (PHEVs), the management of the main drivetrain components and the shift between pure electric and hybrid propulsion is decided by the on-board energy management system (EMS). The EMS decisions have a direct impact on CO2 emissions and need to be optimized to achieve as low emissions as possible. This paper presents optimization methods for EMS algorithms of a parallel P2 PHEV. Two different supervisory control algorithms are examined, employing simulations on a validated PHEV platform. An Equivalent Consumption Minimization Strategy (ECMS) algorithm is implemented and compared to a rule-based one, the latter derived by back-engineering of available experimental data. The different EMS algorithms are analyzed and compared on an equal basis in terms of distance, demanded energy and state of charge levels over different driving cycles. A sensitivity analysis on component sizing interaction with algorithm performance is conducted to check robustness of
Aletras, Nikolaos, Doulgeris, Stylianos, Samaras, Zissis, Ntziachristos, Leonidas
MAHLE Modular Hybrid Powertrain for Large Passenger Cars and Light Commercial Vehicles2022-37-00126/14/2022
Vehicle manufacturers are experiencing a shift in legislation and customer attitudes towards powertrain technologies. To support the pathway towards net-zero emissions by 2050, technologies that significantly reduce CO2 emissions will be needed. This will require increasing levels of electrification, and in the areas of compact cars and urban transportation, the adoption of pure battery electric powertrains is expected to become the dominant technology. For large passenger cars and light commercial vehicles (LCVs) meeting all customer requirements, including range, payload, towing capability, and purchase cost with a pure electric vehicle is challenging and requires the use of heavy and expensive battery packs, which have a high embedded CO2 content. The study builds on the work previously presented on the MAHLE modular hybrid powertrain (MMHP) concept and examines the suitability of this powertrain configuration to meet the future needs of large passenger cars and LCVs. In the MMHP
Harrington, Anthony, Bassett, Michael, Cooper, Adrian, Blaxill, Hugh
Rotorcraft Propulsion System Hybridization for Enhanced Safety and PerformanceF-0078-2022-13045/10/2022
Herein, the case for hybridization will be made, primarily as a means for enhancing safety. Utilizing a case study of a popular light turbine helicopter, it will be shown that augmentation with a parallel hybrid electric system, under two critical operational failures, safety can be significantly enhanced. Conceptual design of two powertrain architectures for parallel turbine-electric hybrid propulsion systems will be examined in sufficient detail to quantify their relative impact in comparison with the existing conventional turbine-only powertrain. Initial trade studies were performed to minimize system weight, utilizing current state-of-the-art components and technology. Commercially available motors, inverters and battery systems were selected for the study. Two architectures were chosen and exercised for three operational scenarios: requirements for 21/2 minutes of emergency power, 5 minutes of emergency power and 10 minutes of emergency power at takeoff/climb power level. Relative
Giannola, Peter, McCann, Gerry, Ho, John C., Chan, Mars
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