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CFD Analysis and Validation of Automotive Windshield De-Fogging Simulation

Mahindra & Mahindra, Ltd.https://www.sae-Gopinath Sathianarayanan
  • Technical Paper
  • 2020-28-0039
To be published on 2020-04-30 by SAE International in United States
Nowadays Climate component system plays a vital role in JD power rating of automotive vehicle. Apart from customer point of view, stringent homologation norms pose challenge in designing climate control system components. At extreme cold climate conditions either mist/ fog forms on the automobile windshield. This makes visibility issue on driver/Co driver side. To overcome this issue efficient demister system is required. Development of Demister system requires thorough knowledge on velocity spread over windscreen and thermal performance of heater (HVAC). This work is aimed for simulating windshield demisting patterns of a vehicle as described by ECC norms. New methodology was developed to simulate the actual behaviour of condensation and evaporation of mist on the windscreen. Transient demisting patterns were simulated with the CFD code and validated with experimental test results.
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A detailed study of prominent factors affecting evaporator frosting in a mobile air conditioning (MAC) system

Tata Motors Ltd-Prasanna V Nagarhalli, Shrikant M Awate, Mubeen Syed
Tata Motors, Ltd.-Anurag Maurya
  • Technical Paper
  • 2020-28-0014
To be published on 2020-04-30 by SAE International in United States
In an automotive air conditioning system, evaporator is well designed for effective heat transfer between refrigerant and air flowing over the evaporator. Hence, the better cooling and dehumidifying the incoming air. Sometimes, at the low ambient temperature and higher relative humidity conditions a frost is observed. It is accumulated over the evaporator and often become thicker enough to block the flow of air completely passing through the evaporator resulting in a rise in vehicle cabin temperature. Current work presents the probable causes of frost formation and their effects on the performance of evaporator and hence, the performance of the automotive air conditioning system. There are four major factors, thermistor poor response, undercharged and overcharged system, clogged air-filter, and also the type of compressor causing frost formation over the evaporator are considered for analysis. Current work presents the experimental analysis of the evaporator performance in the low ambient conditions with the above factors in different iterations. With the above analysis new methods and guidelines can be generated in order to avoid frost formation over the evaporator.
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Impact of different types of glazing on Air- Conditioning system performance of vehicle

Maruti Suzuki India, Ltd.-Akshay Bhateja
  • Technical Paper
  • 2020-01-1249
To be published on 2020-04-14 by SAE International in United States
Due to intense peak summer temperatures and sunny summers in tropical countries like India, achieving the required cabin temperature in vehicle without compromising on fuel efficiency is becoming increasingly challenging. The major source of heat load on vehicle is solar load. Therefore, a study has been conducted to evaluate the heat load on vehicle cabin due to solar radiations and its impact on vehicle Air-Conditioning system performance with various combinations of door glasses and windscreen. The glasses used for this study are classified as Green, Dark Green, Dark Gray, Standard PVB (Polyvinyl Butyral) Windscreen and PVB Windscreen having Infrared Cut particles. For each glass, part level evaluation was done to find out the percentage transmittance of light of different wavelengths and percentage transmittance of heat flux through each glass. To verify the effectiveness of each glass, vehicle level Air-Conditioning system performance test was done in All Weather Chassis Dyno Facility for each retrofitted vehicle. Retrofitted vehicle configurations were decided as per regional visible light transmittance regulations. To eliminate the effect of manufacturing variance while evaluating…
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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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Sensitivity Analysis of Aerodynamic Drag Coefficient to EPA Coastdown Ambient Condition Variation

FCA US LLC-Todd Lounsberry, John Tripp, Gregory Fadler
  • Technical Paper
  • 2020-01-0666
To be published on 2020-04-14 by SAE International in United States
The test cycle average drag coefficient is examined for the variation of allowable EPA coastdown ambient conditions. Coastdown tests are ideally performed with zero wind and at SAE standard conditions. However, often there is some variability in actual ambient weather conditions during testing, and the range of acceptable conditions is further examined in detail as it pertains to the effect on aerodynamic drag derived from the coastdown data. In order to “box” the conditions acceptable during a coastdown test, a sensitivity analysis was performed for wind averaged drag ((CDW ) ̅) as well as test cycle averaged drag coefficients (CDWC) for the fuel economy test cycles. Test cycle average drag for average wind speeds up to 16 km/h and temperatures ranging from 5C to 35C, along with variation of barometric pressure and relative humidity are calculated. The significant effect of ambient cross winds on coastdown determined drag coefficient is demonstrated.
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In-situ studies on the effect of solar control glazings on in-cabin thermal environment for hot and humid climatic zones

Saint Gobain India Pvt., Ltd.-Jyothi Latha Tamalapakula
  • Technical Paper
  • 2020-01-1257
To be published on 2020-04-14 by SAE International in United States
Thermal comfort in a passenger cabin is the basic necessity of an occupant especially in hot and humid climatic conditions. It is known that the reflective glazing solutions provide better thermal comfort inside the cabin due to significant reflection of IR part of solar radiation. However, in hot and humid climatic zones like India, significant reduction in heat load can also be achieved through cost effective solar control absorbing glazings. Thus, the present work aims to study the effect of solar control absorbing glazings on cabin inside temperatures and its impact on thermal comfort of the occupants in tropical climates. A combination of glazing sets with a range of solar energy transmission and absorption values are considered for the study. Indoor soak and cool tests are performed on a sedan model with multiple sets of solar control absorbing glass combinations. A constant ambient temperature of 38˚C and solar radiation of 1000W/m2 are maintained throughout the tests. Wind speed was simulated for a vehicle running speed of 45kmph. Net heat gain inside the cabin as a…
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Artificial Neural Network Based Predictive Approach in Vehicle Thermal Systems Applications

FCA Canada Inc.-Pooya Mirzabeygi, Shankar Natarajan
  • Technical Paper
  • 2020-01-0148
To be published on 2020-04-14 by SAE International in United States
In automotive industry, there is an abundance of test data collected at different stages of vehicle’s development. Heavy reliance on testing can lead to significant increase in vehicle program’s design costs and further delay in the development timing as vehicle instrumentation and testing is costly and time-consuming. This paper focuses on an alternative approach using the Artificial Neural Network (ANN). The ANNs are computing systems inspired by the brain’s biological networks that can learn by considering examples. The “trained” network can then be used to predict the system’s performance in a reliable and efficient manner. This is particularly useful in automotive industry as there exists a considerable amount of test data in the system, sub-system or component level that can be used to train the ANN. The trained ANN can then be used as an alternative for performance prediction and reduce the reliance on additional physical testing. The study focuses on thermal and climate control systems and the application of ANNs to predict the thermal performance. It is shown that ANNs are very robust in…
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Improving Winter Fuel Economy by Using Weather Information

Toyota Motor Corporation-Rino Oshikiri, Hidekazu Hirabayashi
Toyota Motor North America, Inc.-David Cosgrove
  • Technical Paper
  • 2020-01-1241
To be published on 2020-04-14 by SAE International in United States
When the air conditioning (A/C) is turned on, for a cabin climate control system in vehicles, the compressor operation starts and the intake air to the HVAC is to be cooled after the evaporator. This is not only used for cooling the air temperature but also to dehumidify the air. Therefore, even in winters, for a typical automatic climate control system , compressor will automatically operate in order to prevent window from fogging despite its effect on fuel economy. In this process, the air is first cooled to get dried and then heated at the heater core so as to provide dry and hot air to the cabin. As a previous implementation, a humidity sensor was installed on the upper top of the wind shield. Humidity sensor detects the humidity on the wind shield surface and when the probability of window fogging is low the compressor operation is disabled automatically so that we can prevent useless operations of the compressor and increase fuel economy. However, humidity sensor requires some space to be installed and the…
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Lubricant Application, Solid Film, Heat Cured, Corrosion Inhibiting

E-25 General Standards for Aerospace and Propulsion Systems
  • Aerospace Standard
  • AS5528D
  • Current
Published 2020-03-10 by SAE International in United States
This SAE Aerospace Standard (AS) establishes the surface pretreatment, temperature, and baking time required to cure AS5272 lubricant when it is applied over the surfaces of manufactured parts of various metals.
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Laboratory Measurement of Random Incidence Sound Absorption Tests Using a Small Reverberation Room

Acoustical Materials Committee
  • Ground Vehicle Standard
  • J2883_202003
  • Current
Published 2020-03-04 by SAE International in United States
This SAE Recommended Practice describes a laboratory test procedure for measuring the random incidence sound absorption performance of a material or a part in a small size reverberation room by measuring decay rates. The absorption performance may include sound absorption coefficient of the test sample and or the amount of energy absorbed by the test sample. Materials for absorption treatments may include homogeneous materials, nonhomogeneous materials, or a combination of homogeneous, nonhomogeneous, and/or inelastic impervious materials. These materials are commonly installed in the mobility products and in the transportation systems such as ground vehicles, marine products, aircraft, and commercial industry (in industrial and consumer products) to reduce reverberant sound build-up and thus reduce the noise level in the environment by minimizing reflections off of hard surfaces. The test method described herein was developed also to describe a way to measure the absorption performance of a part or a sound package system that will relate to an application. It can be used to rank order materials for application on panels using general automotive steel but also…
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