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A Control System for Maintaining Passenger Cabin Air Quality

Chulalongkorn University-Thanin Wangsawangkul, Thiti Maneepipat, Nattapong Sukumdhanakul, Porpin Pungetmongkol, Prabhath De Silva
DENSO International Thailand-Pradit Mahasaksiri
  • Technical Paper
  • 2020-01-1243
To be published on 2020-04-14 by SAE International in United States
This paper presents a control methodology to maintain vehicle cabin air quality within desirable levels, giving particular attention to gaseous contaminants carbon dioxide (CO2) and carbon monoxide (CO). The CO2 is generated by the occupant exhalation while the CO is assumed to be ingested with the incoming fresh air. The system is able to detect and improve cabin air quality by controlling the recirculation flap of the ventilation system to control the amount of fresh air intake. The methodology is demonstrated in the laboratory using controlled experiments with a production level automotive HVAC (Heating Ventilating and Air-Conditioning) module. The results indicated that the designed control system can work automatically and control the CO and CO2 gas concentrations within acceptable levels.
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Fatigue life Prediction of HVAC pipe assembly for measured powertrain load by virtual simulation

FCA Engineering India Pvt., Ltd.-Sathish Kumar Pandi, C Elango, Kameswara Rao Appana, Roshan N. Mahadule, DivaKaruni Murali Krishna
  • Technical Paper
  • 2020-01-0188
To be published on 2020-04-14 by SAE International in United States
Structural durability of automotive components is one of the key requirements in design and development of today’s automobiles. Virtual simulations are used to estimate component durability to save the cost and time required to build the components and testing. The objective of this work is to find the service life of automotive HVAC pipe assembly by calculating cumulative fatigue life for operation under actual powertrain load conditions. Modal transient response analysis is performed using MSC-Nastran with the measured powertrain load time history. Strain based fatigue life analysis is carried out in n-code using modal superposition method (MSM). The estimated fatigue life was compared with the physical test results. This paper also explains the root cause of low fatigue life on pipe assembly and provide the solution. Keywords: Durability, HVAC Pipe, Powertrain, Modal Transient, Fatigue Life
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Development of the Defrost Performance Evaluation Technology in Automotive using Design Optimization Analysis Method

Hyundai Mobis-Hyeonseok Seo, Jinwon Seo, Bongkeun Choi
  • Technical Paper
  • 2020-01-0155
To be published on 2020-04-14 by SAE International in United States
In this study, we developed the defrost performance evaluation technology using the multi-objective optimization method based on the CFD. The defrosting is one of the key factors to ensure the drivers’ safety using the forced flow having proper temperature from HVAC during drive. There are many factors affecting the defrost performance, but the configurations of guide-vane and discharge angles in the center DEF duct section which are main design factors of the defrost performance in automotive, so these were set to the design parameters for this study. For the shape-optimization study, the discharge mass flow rate from the HVAC which is transferred to the windshield and the discharge areas in the center DEF duct were set to the response parameters. And then, the standard deviation value of mass flow rate on the selected discharge areas checking the uniformity of discharge flow was set to the objective function to find the optimal design. The results on the windshield from optimization analysis were quantified from some kind of standards to evaluate the defrost performance, in particular, the…
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Investigate partial cabin air re-circulation strategy to improve HVAC system's heating performance using 1D simulation

FCA Engineering India Pvt., Ltd.-Saurabh Belsare, Prakashbabuji Danapalan, Saravanan Sambandan
FCA US LLC-Murali Govindarajalu
  • Technical Paper
  • 2020-01-0159
To be published on 2020-04-14 by SAE International in United States
In cold weather conditions, cabin heating performance is critical for retaining the thermal comfort. Heat is absorbed from the engine by circulating coolant through the engine water jacket and same will be rejected by the heater core. A variable speed blower is used to transfer heat from the heater core to the passenger compartment through floor ducts. The time taken to achieve comfortable cabin temperature determines the performance and capacity of heating ventilating and air conditioning (HVAC) system. In current automotive field, the engine options are provided to customers to meet their needs on the same vehicle platforms. Hence few engine variants cannot warm the cabin up to customer satisfaction. To improve the existing warm up performance of system, Positive thermal coefficient heater (PTC), electric coolant PTC heater, auxiliary pump etc. can be used which increases the overall cost of the vehicle. During warm-up, HVAC system operates in 100% fresh mode. In this study, Partial cabin re-circulation is investigated to understand the effect on the cabin warm-up. In order to demonstrate this phenomenon, a one…
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Multi-zone HAVC Development and Validation with Integrated Heated/Vented Seat Control

FCA US LLC-Murad Maghaireh, Michael Hoppe
  • Technical Paper
  • 2020-01-1247
To be published on 2020-04-14 by SAE International in United States
Vehicle multi zone automatic Heating , Venting and Air Conditioning (HVAC) is the advanced form of the traditional air conditioning, the advantage of multi zone automatic HVAC is that it allows the passengers of a vehicle to set a desired temperature for their own zone within the vehicle compartment. This desired temperature is then maintained by the HVAC system, which determines how best to control the available environment data that leads to a higher comfort for the passengers. To achieve ultimate thermal comfort of the occupants in a vehicle, multi zone HVAC takes things a step further by adding heated, vented seats and, steering wheel to the HVAC controller hardware as well as strategies. The heating and cooling of the occupants by this more advance one integrated system is performed by complex control algorithms in form of embedded software programs and private LIN network. This paper describes the approach and tools used to develop, simulate and validate the one integrated climate control system. Included are 1- introduction of an integrated HVAC , steering wheel and…
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Model-Based Calibration of an Automotive Climate Control System

BMW AG-Gerrit Lassahn, Kang Qiu
TU Munich-Patrick Jahn
  • Technical Paper
  • 2020-01-1253
To be published on 2020-04-14 by SAE International in United States
In modern cars the control of heating, ventilation and air-conditioning (HVAC) systems is oftentimes realized by means of a cascade of gain scheduling controllers. The calibration of this control cascade is a complicated and strenuous, hence expensive process. To establish a model based calibration process, a fast executing and accurate model of the HVAC system is required. This paper describes a novel approach for the modelling of an automotive HVAC system. The model consists of a black box model trained with experimental data from a self-developed measurement setup. It is capable to predict the temperature and mass flow of the air entering the vehicle cabin at the different outlets. The measurement setup is based on a combination of temperature and velocity sensors. A measurement fault analysis is conducted to validate the accuracy of the measurement system. As the data collection is done under fluctuating ambient conditions, an extensive analysis of the impact of different ambient conditions on the HVAC unit is performed and incorporated into correction models that account for the different ambient conditions. Different…
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Acoustic performance analysis of automotive HVAC duct designs using a Lattice-Boltzmann based method and correlation with Semi-anechoic chamber.

Dassault Systemes-Prasad Sivakumar, Adrien Mann, Minsuk Kim
FCA Engineering India Pvt., Ltd.-Sivaji Pasupuleti
  • Technical Paper
  • 2020-01-1263
To be published on 2020-04-14 by SAE International in United States
Acoustic comfort of automotive cabins has progressively become one of the key attributes of vehicle design, with wind noise and HVAC noise being two of the key contributors to noise levels heard inside the car. With the increasing prevalence of hybrid technologies and electrification and the associated reduction in powertrain noise levels, the industry has seen an increasing focus on understanding HVAC noise, as it is a main source of noise in the cabin if not the single one when the vehicle is stopped. The complex turbulent flow path through the ducts, combined with acoustic resonances can potentially lead to significant noise generation, both broadband and tonal. In order to avoid time consuming and expensive late stage design changes, or avoid being hit by low consumer rating ignoring the issues, it is important to identify potential problems early in the design process and take appropriate measures to rectify them. In this study, the noise characteristics of three HVAC duct designs are studied using a commercial CFD code based on the Lattice-Boltzmann method. The noise spectra…
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Enhancement of Heat Exchanger Performance Using Oscillatory Flow Phenomena

MED, College of Engineering Pune-Haripriya Rajagopalan, Sakshi Pol, Pradyumna Dhamangaonkar
MED, College of Engineering, Pune-Adhithiya Premchandra Tavorath
  • Technical Paper
  • 2020-01-0943
To be published on 2020-04-14 by SAE International in United States
In this research work, the heat transfer enhancement by using oscillatory flow of thermal fluid between cold and hot reservoir has been analyzed both theoretically and using simulation methods. The main objective of this study is to examine the feasibility of a system working under oscillatory flow conditions compared to its steady flow counterpart. The principle of incrementing thermal diffusion over molecular diffusion by establishing oscillatory flow has been utilized in this case. The system has been designed and the effect of the flow condition has been analyzed using ANSYS Fluent k-epsilon model. A temperature gradient of 50 K has been successfully obtained using the oscillatory flow condition for the assumed capillary dimension of 48 mm. The effect of change in the magnitude and frequency of oscillation on local Nusselt number has been computed. The observed increment in the Nusselt number by increasing the amplitude and frequency of the fluid has been bolstered by analytical calculation. A comparison in the heat transfer of a system working under oscillating and a steady flow conditions has been…
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Parametric Modelling and Performance Analysis of HVAC Defroster Duct Using Robust Optimization Methodology

FCA Engineering India Pvt,, Ltd.-Mohsin Khan
FCA Engineering India Pvt., Ltd.-Nagababu Garikipati
  • Technical Paper
  • 2020-01-1250
To be published on 2020-04-14 by SAE International in United States
Thermal comfort and safety of automotive passengers are the most important factors in the development of the automotive HVAC system. HVAC system is responsible for the demisting and defrosting of the vehicle’s windows and for creating/maintaining a pleasant environment inside the cabin by controlling airflow and temperature. Fog or ice which forms on the windshield is the main reason for invisibility and leads to major safety issue to the customers while driving. It has been shown that proper clear visibility for the windshield could be obtained with a better flow pattern and uniform flow distribution in the defrost mode of the HVAC system and defrost duct. Defroster performance has received significant attention from OEMs to meet the specific global performance standards of FMVSS103 and SAE J902. Therefore, defroster performance is seriously taken into consideration during the design of HVAC system and defroster duct. The HVAC unit provides hot air to the defroster duct which is blowing high velocity air to the windscreen to clear the frosting. Currently as a traditional defrost duct design process, multiple…
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Thermal Behavior of an Electronics Compartment with Respect to Real Driving Conditions

Daimler AG-Heinrich Reister, Thomas Binner
FKFS-Adrian Bernhard, Jochen Wiedemann, Nils Widdecke, Andreas Wagner
  • Technical Paper
  • 2020-01-1299
To be published on 2020-04-14 by SAE International in United States
Reliability of electronic components is of increasing importance for further progress towards automated driving. Thermal ageing processes such as electromigration is one factor that can negatively affect reliability of electronics. Resulting failures are mainly depending on components’ thermal load within vehicle lifetime - called temperature collective, which is described by the temperature frequency distribution of the components. At present, the only possibility to examine the temperature collective is performed by vehicle endurance testing. Knowledge about the temperature frequency distribution in early development stages is one of the key factors to ensure electronics’ reliability in future vehicles. Vehicle Thermal Management (VTM) tools, which provide numerical simulation, allows lifetime thermal prediction in early development stages, but also challenges current VTM processes. Due to changing focus from underhood to numerous electronic compartments in vehicles, the number of simulation models has steadily increased. Since the electronics compartments are mostly located inside the vehicle cabin, common load cases such as the “Slow Uphill Drive” and the “High Speed” cannot be applied to these models. Defining new load cases for maximum…