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Multitarget Evaluation of Hybrid Electric Vehicle Powertrain Architectures considering Fuel Economy and Battery Lifetime

McMaster University-Phillip Kollmeyer, Ali Emadi
Politecnico di Torino-Pier Giuseppe Anselma, Giovanni Belingardi
  • Technical Paper
  • 2020-37-0015
To be published on 2020-06-23 by SAE International in United States
Hybrid Electric Vehicle (HEV) powertrains are characterized by a complex design environment as a result of both the large number of possible layouts and the need for dedicated energy management strategies. When selecting the most suitable hybrid powertrain architecture at early design stage of HEVs, engineers usually focus on fuel economy (directly linked to tailpipe emissions) and vehicle drivability performance solely. However, high voltage batteries are a crucial component of HEVs as well in terms of performance and cost. This paper introduces a multitarget assessment framework for HEV powertrain architectures which considers both fuel economy and battery lifetime. A multi-objective formulation of dynamic programming is initially presented as off-line optimal HEV energy management strategy capable of predicting both fuel economy performance and battery lifetime of HEV powertrain layout options. Subsequently, three different HEV powertrain architectures are considered as test cases for the developed HEV assessment methodology including parallel P2, series-parallel P1P2 and power-split layouts. A comparison of numerical results for the three HEV powertrain test cases is then performed in terms of optimal fuel economy…
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Next-Generation Refrigerant and Air Conditioner System Choice for Internal Combustion, Hybrid and Electric Vehicles (Presentation Only) by Stephen O. Andersen, Jiangping Chen, Sourav Chowdhury, Tim Craig, Walter Ferraris, Jianxin Hu, Sangeet Kapoor, Carloandrea Malvicino, Prasanna Nagarhalli, Nancy J. Sherman, and Kristen N. Taddonio

Centro Ricerche Fiat SCpA-Walter Ferraris
FCA ITALY S.p.A.-Carloandrea Malvicino
  • Technical Paper
  • 2020-37-0029
To be published on 2020-06-23 by SAE International in United States
With the passage of Kigali Amendment to the Montreal Protocol in 2016, HFC-134a will need to be phased down in all markets worldwide due to its high global warming potential (GWP=1300). Meanwhile, global adoption of electric vehicles is accelerating. Improved MAC and heat pump efficiency is critically important to extend vehicle range. Engineers must design MAC and heat pump systems using low-GWP refrigerants that are simultaneously cost-effective, energy efficient, safe, reliable, affordable for consumers, and able to provide both cooling and heating of the cabin and thermal management of vehicle components like power electronics and batteries. This is a challenging and complex task. Fortunately, solutions are available, but they may diverge from traditional direct expansion systems of the past. This paper: 1) documents the global history and market status of the development of alternatives to HFC-134a, including secondary-loop (SL-MAC) systems; 2) outlines the existing and expected regulations demanding low-GWP MAC refrigerant and high fuel efficiency; 3) explains the importance of comprehensive LCCP analysis when evaluating MAC climate impacts instead of focusing on only one component…
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NVH Comfort of Range Extenders for Electric Vehicles

FEV Europe GmbH-Christoph Steffens, Georg Eisele, Frank Wolter
  • Technical Paper
  • 2020-01-1551
To be published on 2020-06-03 by SAE International in United States
The most appreciated driving characteristics of electric vehicles are the quietness and spontaneous torque rise of the powertrain. The application of range extenders (REX) with internal combustion engines (ICEs) to increase the driving range is a favourable solution regarding costs and weight, especially in comparison with larger battery capacities. However, the NVH integration of a REX is challenging, if the generally silent driving characteristics of electric vehicles shall remain preserved. This paper analyses key NVH aspects for a REX design and integration to fulfil the high expectations regarding noise and vibration comfort in an electric vehicle environment. The ICE for a REX is typically dimensioned for lower power outputs, incorporating a low number of cylinder units, which is even more challenging concerning the NVH integration. The basic REX concept is evaluated by considering power and fuel efficiency demands in combination with an interior noise forecast. It will be explained that sophisticated, innovative technologies are required on component and vehicle side to ensure best possible NVH comfort. On component side, essential excitations must be addressed. In…
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Optimization Of Vehicle Damping Sheets Position Based On Energy Calculation

BAIC Motor Corporation., Ltd-Lie Wu, Huimin Zhuang, Bin Hou
Beijing Automotive Technology Center Co.-Zhiwen Wang, Na Li, Yuping Miao
  • Technical Paper
  • 2020-01-1528
To be published on 2020-06-03 by SAE International in United States
As a common means for reducing vibration and noise for automobiles, damping material is usually employed in the vehicle body, typically on the floor, the dashboard, and the top roof. With the growing demand of fuel economy, light weighting, as well as NVH comfort, the optimization of the damping pads has become a topic of increasing importance. In numerical simulation, the traditional methods generally make use of the modal strain energy of the metal sheet as the main indicator for making layout choice for the damping pads. The optimization is not performed according the vehicle’s real working condition. Furthermore, the traditional methods do not depend on the accurate properties of the damping material. In this paper, a novel optimization method based on energy analysis is presented. This method relies on the subdivision of the vehicle body area into finite number of patches (composed of finite elements), and the energy computation of the vibration and noise indicators when a general damping property (modal damping) is applied on each patch consecutively in a loop. Such operation allows…
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Effect of Variable Geometry Fin in Automotive Condenser using Analytical and CFD Approach

Mahindra & Mahindra, Ltd.-Ram Anandan
  • Technical Paper
  • 2020-28-0028
To be published on 2020-04-30 by SAE International in United States
Due to stiff competition among the Original Equipment Manufacturer (OEM's), the Comfort, Fuel efficiency & Safety are the key factors that drive the vehicle business, from that context Air Conditioning for a car plays a pivotal role in the area of comfort of the passengers and fuel efficiency point of view. In addition, condenser plays a pivotal role in Power train cooling system & air conditioning system. Therefore, it is a big challenge for the automotive engineer to propose an innovative design that can improve the thermal performance of Condenser without not compromise the package size. Also, it's a challenge for the OEM's to select the optimal heat exchanger from the supplier basket during the design phase of product development cycle. The objective of this paper to focus on analytical calculation or frame work was developed using excel tool considering the variable geometry of fin which includes louver pitch, louver angle and louver length in a multi-pass condenser. Further this theoretical calculation was validated using experimental data and CFD simulation. This theoretical excel tool can…
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Influence of Port Water Injection on the Combustion Characteristics and Exhaust Emissions in a Spark-Ignition Direct-Injection Engine

Shanghai Jiao Tong University-Yadong Fan, Tianbao Wu, Xuesong Li, Min Xu, David Hung
  • Technical Paper
  • 2020-01-0294
To be published on 2020-04-14 by SAE International in United States
It is well known that engine downsizing is still the main energy-saving technology for spark-ignition direct-injection (SIDI) engine. However, with the continuous increase of the boosting ratio, the gasoline engine is often accompanied by the occurrence of knocking, which has the drawback to run the engine at retarded combustion phasing. Besides, in order to protect the turbine blades from being sintered by high exhaust temperature, the strategies of fuel enrichment are often taken to reduce the combustion temperature, which ultimately leads to a high level of particulate number emission. Therefore, to address the issues discussed above, the port water injection (PWI) techniques on a 1.2-L turbocharged, three-cylinder, SIDI engine were investigated.Measurements indicate that the optimization of spark timing has a significant impact on its performance. The two factors of the water substance itself and spark advance caused by the knock mitigation are trade-offs, which eventually affect the combustion performance. Under knock limited spark advance (KLSA) condition, we find that the application of port water injection could effectively advance the combustion phasing and reduce exhaust gas…
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Downsized-Boosted Gasoline Engine with Exhaust Compound and Dilute Advanced Combustion

General Motors LLC-Jeremie Dernotte, Paul M. Najt, Russell P. Durrett
  • Technical Paper
  • 2020-01-0795
To be published on 2020-04-14 by SAE International in United States
This article presents experimental results obtained with a disruptive engine platform, designed to maximize the engine efficiency through a synergetic implementation of downsizing, high compression-ratio, and importantly exhaust-heat energy recovery in conjunction with advanced lean/dilute low-temperature type combustion. The engine architecture is a supercharged high-power output, 1.1-liter engine with two-firing cylinders and a high compression ratio of 13.5: 1. The integrated exhaust heat recovery system is an additional, larger displacement, non-fueled cylinder into which the exhaust gas from the two firing cylinders is alternately transferred to be further expanded.The main goal of this work is to implement in this engine, advanced lean/dilute low-temperature combustion for low-NOx and high efficiency operation, and to address the transition between the different operating modes. Those include well-mixed charge compression-ignition at low-load, and a mixed-mode combustion at higher loads, before transitioning to boosted homogenous and stochiometric spark-ignited combustion. Here, the mixed-mode combustion strategy is composed of a deflagration of a stratified mixture created by a late direct injection, then triggering a controlled autoignition of the surrounding gas, improving the robustness…
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Gear Shift Pattern Optimization for Best Fuel Economy, Performance and Emissions

Chidhanand S.
Mahindra & Mahindra, Ltd.-Lemuel Paulraj, Saravanan Muthiah
  • Technical Paper
  • 2020-01-1280
To be published on 2020-04-14 by SAE International in United States
As the FTP-75 drive cycle does not have a prescribed gear shift pattern, automotive OEMs have the flexibility to design. Conventionally, gear shift pattern was formulated based on trial and error method, typically with 10 to 12 iterations on chassis dynamometer. It was a time consuming (i.e. ~ 3 to 4 months) and expensive process. This approach led to declaring poor fuel economy (FE). A simulation procedure was required to generate a gear shift pattern that gives optimal trade-off amongst conflicting objectives (FE, performance and emissions). As a result, a simulation tool was developed in MATLAB to generate an optimum gear shift pattern. Three different SUV/UV models were used as test vehicles in this study. Chassis dyno testing was conducted, and data was collected using the base and optimized gear shift patterns. Dyno test results with optimized gear shift pattern showed FE improvement of ~ 4 to 5% while retaining the NOx margin well above engineering targets. This labeling FE improvement method did not require any hardware or software changes, thus, involved no additional expense.…
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Development of New Hybrid Transaxle for Mid-Size Sports Utility Vehicles

Toyota Motor Corporation-Seitaro Nobuyasu, Shigetsugu Iwata, Masabumi Nishigaya, Yoshiteru Hagino, Masatoshi Ito, Hiroshi Aihara
  • Technical Paper
  • 2020-01-0850
To be published on 2020-04-14 by SAE International in United States
Toyota has developed a new Hybrid (HV) transaxle P810 for Mid-Size SUVs to improve fuel efficiency and power performance. The transaxle was developed based on Toyota's new development strategy - Toyota New Global Architecture (TNGA). By adopting technologies to shorten overall length of the transaxle, installation into the same engine compartment of Mid-Size sedans have been realized while also improving the motor output. This paper will introduce technologies regarding the new mount structure for shortening overall length, and furthermore, noise reduction related to this mount structure.
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Evaluating the Performance of a Conventional and Hybrid Bus Operating on Diesel and B20 Fuel for Emissions and Fuel Economy

US Environmental Protection Agency-Matthew Brusstar, Scott Ludlam
University of Michigan-Rinav Pillai, Andre Boehman
  • Technical Paper
  • 2020-01-1351
To be published on 2020-04-14 by SAE International in United States
With ongoing concerns about the elevated levels of ambient air pollution in urban areas and the contribution from heavy-duty diesel vehicles, hybrid electric vehicles are considered as a potential solution as they are perceived to be more fuel efficient and less polluting than their conventional engine counterparts. However, recent studies have shown that real-world emissions may be substantially higher than those measured in the laboratory, mainly due to operating conditions that are not fully accounted for in dynamometer test cycles. At the U.S. EPA National Fuel and Vehicle Emissions Laboratory (NVFEL) the in-use criteria emissions and energy efficiency of heavy-duty class 8 vehicles (up to 36280 kg) can be evaluated under controlled conditions in the heavy-duty chassis dynamometer test. The present study evaluated the performance of a conventional bus and a hybrid bus for emissions and fuel economy under representative test cycles (including cold start and hot start conditions) with Diesel (#2) and Biodiesel (B20) fuel. The conventional bus was equipped with a Cummins ISL 8.3L engine and a Diesel Particulate Filter (DPF) and Diesel…