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General Motors Full Scale Wind Tunnel Upgrade

General Motors LLC-Nina Tortosa
Jacobs Technology-Paul Nagle, Tyler Brooker
  • Technical Paper
  • 2020-01-0687
To be published on 2020-04-14 by SAE International in United States
The General Motors Aero Lab’s Full Scale Wind Tunnel Facility, which came into operation in August of 1980, has undergone the significant upgrade of installing a state-of-the-art moving ground plane system. After almost four decades of continued use the full-scale wind tunnel also received some significant maintenance to other areas, including a new heat exchanger, main fan overhaul, and replacement of the test section acoustic treatment. A 5-belt system was installed along with an integrated vehicle lift system. The center belt measures 8m long, and can accommodate two belt widths of 1100mm and 900mm. Flow quality and other wind tunnel performance parameters were maintained to prior standards which are on par with the latest industry standards. The new 5-belt rolling road system maintains GM’s industry leading vehicle aerodynamic development and the improved acoustic panels ensure GM continues to develop vehicles with leading class acoustics.
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IC engine internal cooling system modelling using 1D-CFD methodology

FCA Engineering India Pvt., Ltd.-Dhananjay Sampat Autade, Amit Kumar, Tharunnarayanan Arthanari, Vaibhav Patil, Kamalakannan J
FCA US LLC-Fu-Long Chang
  • Technical Paper
  • 2020-01-1168
To be published on 2020-04-14 by SAE International in United States
Internal combustion engine gets heated up due to continuous combustion of fuel. To keep engine working efficiently and prevent components damage due to very high temperature, the engine needs to be cooled down. Based on power output requirement and provision for cooling system, every engine has it’s unique cooling system. Liquid based cooling systems are majorly implemented in automobile. It’s important to keep in mind that during design phase that, cooling the engine will lower the power to fuel consumption ratio. Therefore, during lower ambient conditions, the cooling system should be able to uniformly increase the temperature of the engine components, engine oil and transmission oil. This is achieved by circulating the coolant through cooling jacket, engine oil heater and transmission oil heater, which will be heated by the combustion heat. The objective of this study is to build a steady state 1D-model of cooling system; comprising of water pump, cooling jacket, engine head, thermostat, radiator, cabin heater, engine and transmission oil heaters with plumbing system. This 1D model is used to simulate vehicle drive…
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Modeling of an Integrated Internal Heat Exchanger and Accumulator in R744 Mobile Air-Conditioning Applications

University of Illinois at Urbana-Champaign-Wenying Zhang, Predrag Hrnjak
  • Technical Paper
  • 2020-01-0153
To be published on 2020-04-14 by SAE International in United States
Carbon dioxide (R744) is one of the most promising next-generation refrigerants for mobile air-conditioning applications (MAC), which has the advantages of good heating performance in cold climates and environmental-friendly properties. In this paper, a simulation model of an integrated internal heat exchanger (IHX) and accumulator (ACC) was developed using the finite volume method via EES. The results were validated by experimental results from a transcritical R744 mobile heat pump, and the error was within ±5%. The impacts of mass flow rate, evaporator outlet quality and temperatures of high- and low-side streams on the heat transfer rate, effectiveness and charge of the integrated IHX/Acc were studied. Results show that the heat transfer rate of the IHX is mostly sensitive to the evaporator outlet quality. When the evaporator quality decreases from 0.9 to 0.6, the heat transfer rate increases from 1.1 to 2.4 kW and the superheat reduces from 25.8 to 9.4 ℃. As a result, the compressor discharge temperature and the heating capacity can be reduced. To obtain the maximized capacity, especially during the startup, an…
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Utilization of bench testing in vehicle thermal system development for extreme cold ambient condition

FCA US LLC-Masuma Khandaker, Ahmed Uddin, Vijay Sanikal, Kaji Fuad, Craig Lindquist, Gary Baker, Sadek Rahman
  • Technical Paper
  • 2020-01-1390
To be published on 2020-04-14 by SAE International in United States
Automotive thermal systems are becoming complicated each year. The powertrain efficiency improvement initiatives are driving transmission and engine oil heaters into coolant network design alternatives. The initiatives of electrified and autonomous vehicles are making coolant networks even more complex. The coolant networks these days have many heat exchangers, electric water pumps and valves, apart from typical radiators, thermostat and heater core. Some of these heat exchangers including cabin heaters deal with very small amount of coolant flow rates at different ambient conditions. This paper describes how viscosity can be a major reason for simulation inaccuracy, and how to deal with it for each component in the coolant network. Both experimental and computational aspects have been considered in this paper with wide range of ambient temperatures. Methods have been proposed to handle these issues in the simulation phase at the early phase of automotive thermal system development, especially during extreme cold ambient conditions.
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Light Duty Truck Rear Axle Thermal Modeling

FCA-Mohammad Nahid
FCA US LLC-Joydip Saha, 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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Co-simulation Methodology for PHEV Thermal System Development

FCA US LLC-Rezwanur Rahman, Auvi Biswas, Craig Lindquist, Masuma Khandaker, Sadek Rahman
  • Technical Paper
  • 2020-01-1392
To be published on 2020-04-14 by SAE International in United States
Thermal development of automotive applications is a lot more complex than it used to be in the past. Specifically, for Plug-in Hybrid Electric Vehicles (PHEVs), all the sub-systems are so intertwined that it’s hard to analyze them as sub-systems only. A system level solution is needed for proper sizing of components. For early thermal development, a co-simulation method can ensure that we take into account the inter-dependency of all the thermal features in the car. As for example a large PHEV battery may need to be passively cooled by refrigerant, which is in turns associated with the interior HVAC cooling system. For proper sizing of the condenser, chiller etc., one has to account for the battery cooling and cabin cooling as one system. There are also many thermal actuators on a PHEV, e.g. control valves, pulse-width-module (PWM) pumps, electric compressor, electric coolant heaters etc. Smart controls and calibration development early in the product development can impact sizing of front end cooling modules and other heat exchangers significantly. The design of hardware and software has to…
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Development of Cooling Fan Model and Heat Exchange Model of Condenser to Predict the Cooling and the Heat Resistance Performance of Vehicle

Honda R&D Co., Ltd.-Yuichi Fukuchi, Kunihiko Yoshitake, Kazutaka Yokota
  • Technical Paper
  • 2020-01-0157
To be published on 2020-04-14 by SAE International in United States
The cooling performance and the heat resistance performance of commercial vehicle are balanced with aerodynamic performance, output power of power train, styling, the location of sensors, cost and many other parameters. Therefore, it is desired to predict the cooling performance and the heat resistance performance with high accuracy at the early stage of development. Three forms of heat transfer consist of conduction, convection and radiation. Among of these components, it is sometimes difficult to solve the thermal conduction accurately, because to prepare accurate shape and properties needs lots of time and efforts at the early stage of development. Therefore, the cooling performance of heat exchangers and the air temperature distribution in the engine compartment are predicted to access the cooling and the heat resistance performance of vehicle at the preliminary design stage. The air temperature distribution is dominated by the distribution of heat radiation on heat exchangers, the flow distribution which is produced by fans and thermal convection at the surface of parts in the engine compartment. For the case of middle or high vehicle…
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A Competitive Approach to an Active Exhaust Heat Recovery System Solution

Tenneco Inc.-Adam Kotrba, Timothy Gardner, John Stanavich, Rapael Bellard, Brian Kunkel, Nicholas Morley
  • Technical Paper
  • 2020-01-0161
To be published on 2020-04-14 by SAE International in United States
As greenhouse gas regulations continue to tighten, more opportunities to improve engine efficiency emerge, including exhaust gas heat recovery. Upon cold starts, engine exhaust gases downstream of the catalysts are redirected with a bypass valve into a heat exchanger, transferring its heat to the engine coolant to accelerate engine warm-up. This has several advantages, including reduced fuel consumption, as the engine’s efficiency improves with temperature. Furthermore, this accelerates readiness to defrost the windshield, improving both safety as well as comfort, with greater benefits in colder climates, particularly when combined with hybridization’s need for engine on-time just for cabin heating. Such products have been in the market now for several years; however they are bulky, heavy and expensive, yielding opportunities for competitive alternatives. Customer voice expresses needs for less complex designs that reduce package space, mass, and part count (i.e. cost) while maintaining or improving performance, including the integration of an active rather than passive exhaust bypass control valve. This paper highlights the design evolution of EHRS, including relative benchmarking of competing products, comparing various aspects…
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Sound Evaluation of Flow-induced Noise with Simultaneous Measurement of Flow Regimes at TXV Inlet of Automotive Evaporators

University of Illinois-Stefan Elbel
University of Illinois at Urbana-Champaign-Yingyue Zhang
  • Technical Paper
  • 2020-01-1255
To be published on 2020-04-14 by SAE International in United States
In the air conditioning system, flow-induced noise is very disturbing, including the noise generated from the expansion device and the heat exchangers. In the past few decades, most researches related to flow-induced noise focused on the relationship between the flow regimes near the expansion device and the amplitude of flow-induced noise when the measurements are not synced. In this paper, an experimental-based approach is used to explore the simultaneous relationship between flow-induced noise characteristics and flow regimes at the inlet of TXV of evaporators used in automobiles. A pumped R134a loop with microphones and transparent sections is used to simulate the vapor compression system. Also, the paper evaluates the severity of flow-induced noise from not only the amplitude of noise but also the frequency of noise with a parameter called psychoacoustic annoyance (PA). One of the most disturbing flow-induced noise near the TXV is called gurgling noise and distributes around 9 kHz at an amplitude between 40 dB to 50 dB. When the TXV inlet is subcooled, the annoyance of flow-induced noise is substantially reduced.…
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Onboard Ethanol-Gasoline Separation System for Octane-on-Demand Vehicle

Honda R&D Co., Ltd.-Hiroshi Chishima, Daiko Tsutsumi, Toru Kitamura
  • Technical Paper
  • 2020-01-0350
To be published on 2020-04-14 by SAE International in United States
Bio-ethanol is being used worldwide as an alternative fuel because of CO2 emission reduction and energy sustainability. It is common knowledge that ethanol has an advantage of high anti-knock quality. It is also well known that enhancement of both fuel economy and high load performance for general gasoline engines are limited by knocking. In order to increase anti-knock performance, a fuel system was developed to separate ethanol blended gasoline fuel into high-octane number fuel (high-concentration ethanol fuel) and low-octane number fuel (low-concentration ethanol fuel) on a vehicle. The onboard fuel separation system, installed in the fuel tank, mainly consists of a pervaporation membrane module, a fuel supply pump for the membrane, heat exchangers for fuel heating, a condenser for the permeated fuel vapor and a vacuum pump to control the pressure on the permeation side. Vapor that was not condensed at the condenser is supplied to the engine through a canister purge line. In this study, it was revealed that the onboard fuel separation system has controllability sufficient for use in automobiles by evaluating the…