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Simplified Approach to Model a HEV/PHEV/Battery Vehicle Cooling System in 1D and validating using DFSS methodology

Detroit Engineered Products (DEP) Inc-Toukir Islam
FCA Engineering India Pvt Ltd-AMIT KUMAR, VAIBHAV PATIL, Dhananjay Autade, Kamalakannan J
  • Technical Paper
  • 2020-01-1386
To be published on 2020-04-14 by SAE International in United States
ABSTRACT Improving fuel economy and to satisfy more restrictive emission legislation the Vehicle electrification becomes more important one. Compared to the combustion engine a Hybrid electric vehicles / Plug-in hybrid electric vehicles will use energy from the grid to recharge their high voltage battery and this is converted with much higher efficiency, and less CO2 emission so they will have a significant role in the present transition from conventional to electric vehicles. The addition of new components, such as power electronics, electric machine and high voltage battery, increases the maximum torque available and the energy stored on-board, but increases the weight as well. In addition, although they have really high efficiency, they produce a significant amount of heat that has to be removed. Another thermal management issue in PHEV and BEV is cabin heating, since the engine heat is not available. To guarantee system efficiency and reliability, a completely new thermal management layout has to be designed. The time and cost spent on a real time model of new cooling system will be more which…
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Study on thermal management strategy of the exhaust gas of diesel engines based on in-cylinder injection parameters

Tongji Univ-Piqiang TAN, Erfeng Li, Zhiyuan Hu, Diming Lou
Tongji Univ.-Lishuang Duan
  • Technical Paper
  • 2020-01-0621
To be published on 2020-04-14 by SAE International in United States
Due to high thermal efficiency, reliability and durability, less fuel consumption, and less carbon dioxide (CO2) emission, diesel engines are widely used in both stationary and mobile applications. However, an inherent combustion mode of diesel engines results in harmful emissions like hydrocarbons (HC), carbon monoxide (CO) and particulate matter (PM), the emissions can cause substantial damage to the human health and environment, so there are strict emission regulations to limit the harmful emissions. Diesel oxidation catalyst (DOC) and diesel particulate filter (DPF) are important exhaust gas aftertreatment devices to oxidizing the HC, CO and PM in order to meet the requirements of emission regulations. However, emission regulations become more stringent, the test procedure has been changed from New European Driving Cycle (NEDC) to Worldwide Harmonised Light Vehicle Test Procedure (WLTP), most of the test operating conditions in the WLTP are under medium and low engine loads, so the temperature of exhaust gas of diesel engines is relatively low during the whole WLTP cycle. For the exhaust gas aftertreatment system, especially for the regeneration process of…
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Light Duty Truck Rear Axle Thermal Modeling

FCA-Sadek Rahman
  • Technical Paper
  • 2020-01-1388
To be published on 2020-04-14 by SAE International in United States
More stringent Federal emission regulations and fuel economy requirements have driven the automotive industry toward more sophisticated vehicle thermal management systems to best utilize the waste heat and improve driveline efficiency. The final drive unit in light and heavy duty trucks usually consists of geared transmission and differential housed in a lubricated axle. The automotive rear axles is one of the major sources of power loss in the driveline due to gear friction, churning and bearing loss and have a significant effect on overall vehicle fuel economy. These losses vary significantly with the viscosity of the lubricant. Also the temperatures of the lubricant are critical to the overall axle performance in terms of power losses, fatigue life and wear. In this paper, a methodology for modeling thermal behavior of automotive rear axle with heat exchanger is presented to predict the axle lubricant temperature rise and study the effect of coolant temperature on the axle warm-up and efficiency for a typical EPA fuel economy driving cycle. Thermal axle consists of automotive rear axle with a heat…
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Optimization of Diesel Engine and After-treatment systems for a Series Hybrid Forklift Application

IAV Automotive Engineering Inc-Yinyan Huang, Thaddaeus Delebinski
IAV GmbH-Reza Rezaei, Rico Möllmann
  • Technical Paper
  • 2020-01-0658
To be published on 2020-04-14 by SAE International in United States
This paper investigates an optimal design of a diesel engine and after-treatment system for a series hybrid electric forklift application. A holistic modeling approach is developed in GT-Suite® to establish a model-based hardware definition for a diesel engine and after-treatment system that accurately predicts engine performance and emissions of a baseline system. The developed engine model performance is validated with the experimental data. Then, the engine design including compression ratio, boost level, air-fuel ratio (AFR), injection timing, and injection pressure is optimized at a single operating point for the series hybrid electric vehicle, while considering the performance of the after-treatment components. The engine and after-treatment models are then coupled with a series hybrid electric powertrain to evaluate the performance of the forklift in the standard VDI 2198 drive cycle. In addition, the thermal management strategies like retarding injection timing and late post-injection of fuel during cold start are analyzed and optimally selected in this work. The results show the reduction of tailpipe-NOx emission is possible by properly retarding the injection timing without significant effect on…
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Investigation of the operating conditions on the water and thermal management for a polymer electrolyte membrane fuel cell by one-dimensional model

Tongji Universtiy-Xuhui Wang, Yaqian Dong, Sichuan Xu
  • Technical Paper
  • 2020-01-0856
To be published on 2020-04-14 by SAE International in United States
Water and thermal management is an essential issue that influences performance and durability of a polymer electrolyte membrane fuel cell (PEMFC). Water content in membrane decides its ionic conductivity and membrane swelling favors the ionic conductivity, resulting in decreases in the membrane’s ohmic resistance and improvement in the output voltage. However, if excessive liquid water can’t be removed out of cell quickly, it will fill in the pores of catalyst layer (CL) and gas diffusion layer (GDL) then flooding may occur. It is essential to keep the water content in membrane at a proper level. In this work, a transient isothermal one-dimensional model is developed to investigate effects of the relative humidity of inlet gas and cell temperature on performance of a PEMFC. Comprehensive physical and chemical phenomenon inside the cell is included, especially the mass transfer of hydrogen, oxygen, vapor and liquid water in gas channels, GDL and CL and non-frozen membrane water in ionomer. Phase change between vapor and liquid water is also considered. The cell’s performances at the conditions of the different…
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CFD Modeling of the Oscillating Heat Transfer inside Diesel Engine Pistons

Dalian University of Technology-Peng Wang, Xin Meng, Ruobing Liang
Incheon National University-Sungmin Yoon
  • Technical Paper
  • 2020-01-0163
To be published on 2020-04-14 by SAE International in United States
Ever increasing heat flux inside combustion chamber has drawn a lot of concerns from automakers. As one of the most critical components in engines, the piston suffers periodic heat and mechanical loadings due to the prolonged expose to the high-temperature combustion gas. How to cool the piston effectively and accurately becomes one of the determining factors to ensure the reliability and durability of diesel engines. At present, there’re several approaches to remove the heat flux from the piston. The cooling gallery, as one of the most efficient cooling methods for pistons, has been widely used for their thermal managements. However, it’s really difficult to understand what really happens inside the cooling gallery, as it’s deeply located within the piston head. Although a series of experiments have been conducted in previous studies, they’re all based on a quasi-steady-state assumption. Only an average heat transfer coefficient throughout one cycle can be obtained, which fails to provide the transient flow and heat transfer processes in details. During the engine operation, the piston takes a periodic motion under the…
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Mitigation of Accelerated degradation of Li-ion Batteries for High Rate Discharge Application

CCDC Ground Vehicle Systems Center-Yi Ding, Laurence Toomey
Ground Vehicle Systems Center-Tony Thampan
  • Technical Paper
  • 2020-01-0452
To be published on 2020-04-14 by SAE International in United States
The U.S. Army has been pursuing vehicle electrification to achieve enhanced combat effectiveness. The benefits include new capabilities that require high power pulse duty cycles. However as the vehicle platform size decreases, the Energy Storage System (ESS) pulse power discharge rates ( > 40 C rate) can be significantly greater than commercial Hybrid Electric Vehicle ESS, resulting in significantly lower ESS lifetimes. Results of high power pulse duty cycles on lithium iron phosphate cell lifetime performance show a dramatic loss. For a 2 s and 3 s pulse duration tests, the observed degradation is 22 % and 32 % respectively. Although these cells were thermally managed in a convective chamber at 10℃, the 2 s pulse showed a 31℃ temperature rise and the 3 s pulse, a 48℃ temperature rise. The decreased lifetime is as a result of chemical degradation due to the increased temperature, and potentially, mechanical degradation due to pulse induced diffusion stresses. Both of these mechanisms lead to lithium loss and eventual capacity loss. To mitigate the thermally induced degradation, due to…
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Experimental and Numerical Investigation of the Multiphase Flow and Heat Transfer in an Oil Jet Cooled Engine Piston

GM-Jeff Schlautman
Simerics Inc-Yawei Chen, Sujan DHAR
  • Technical Paper
  • 2020-01-0165
To be published on 2020-04-14 by SAE International in United States
The piston temperature has to be carefully controlled to achieve effective and efficient thermal management in internal combustion engines. One of the common methods to cool piston is by injecting oil from the crankcase underside to the piston under-crown area. In the present study, a novel 3D multiphase thermal-fluid coupled model is developed using the commercial CFD software SimericsMP+ to study the piston cooling using the oil jet. In this model, an algorithm is proposed to couple the fluid and solid computation domain to account for the different timescale of heat transfer in the fluid and solid due to the high thermal inertia of the solid piston. Combustion heat flux on the piston surface and the liner temperature distribution are used as the boundary conditions. The temperature-dependent material properties, piston motion, and thermal contact resistance between the ring and piston are also accounted for. The oil film on the piston under-crown area is captured in the model to ensure an accurate prediction of the heat transfer coefficient. The piston temperature from the numerical simulation is…
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Design and Thermal Analysis of Lithium-Ion Battery for an Electric Racing Car

Hefei University of Technology-Shuhua LI, Bofu WU, Peng WANG, Yongjia WANG
Jilin University-Dawei QU
  • Technical Paper
  • 2020-01-0167
To be published on 2020-04-14 by SAE International in United States
It is well known that battery thermal management system (BTMS) has been paid more attentions with the development of lithium-ion batteries. To meet the requirements of electric vehicles to supply long driving range and adequate acceleration, lithium-ion battery packs are often arranged very compactly with small internal, which poses a challenge to the design of BTMS. BTMS has great influence on performance, lifespan and safety of the battery pack and is an essential part of battery pack design. For racing cars that are often in extreme conditions, thermal safety of the battery is very important. The battery pack in this study is consisted of 170 cells connected in series and/or in parallel, 5 boxes made of sheet molding compound (SMC) material and aluminum partition to provide the necessary power for electric racing car. In this work, the computational fluid dynamic (CFD) analysis is performed to investigate the forced air cooling system. The thermal behavior of battery pack under different constant-current (CC) discharge was performed using CD-adapco's STAR-CCM+ solver. This study shows that passive air cooling…
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Vehicle Design Considerations Enabling High-Performance Charging

Magna Steyr Fahrzeugtechnik AG & Co KG-Christian Josef Paar, Helmut Martin Waser, Heimo Kreimaier, Inés Cuenca-Jaen, Florian Eibler
  • Technical Paper
  • 2020-01-1440
To be published on 2020-04-14 by SAE International in United States
Customer requirements such as range anxiety are the driver for increasing the charging power of battery-electric vehicles. High-performance charging theoretically enables time targets of faster than 30 kilometers (19 miles) recharging per minute. Due to physical limitations (i.e., current limits of the components available) a charging power of greater than 200 kilowatt arises the question of the voltage level required to fulfill the power demand. One possible approach to achieve high charging power is increasing the battery voltage, i.e., increasing the voltage level from 400 V to 800 V is one simple measure. This publication discusses the main aspects of charging by incorporating all high-voltage components in the vehicle. An increase of the voltage level and charging power affects all high-voltage components, especially the thermal management of the battery needs special consideration. High-voltage vehicle architecture design considerations are discussed including thermal-management and battery-design aspects. Different charging curves from existing vehicles are compared with a generic fast charging profile which is defined using theoretical background of available cells including consideration of physical and chemical limits (e.g.,…