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Computational Fluid Dynamics (CFD) tools play an important role in the early stages of vehicle aerothermal development. Arguably, the RANS (Reynolds Averaged Navier-Stokes) approaches are most widely used in industry due to their acceptable accuracy with affordable computational cost and faster turnaround time. In many automotive flows, RANS models cannot very accurately capture the absolute flow features or even the integral force coefficients. In spite of this, the RANS based CFD prediction results can conveniently be used to assess the magnitude and direction of a trend. However, even for such purposes, notable disagreements often exist between the flow features predicted by different RANS turbulence models. Whilst comparisons of different RANS models for various applications are abundant in literature, such evaluations on full-car models are limited, especially the evaluations of the cooling airflow inside the underhood compartment.

The demand for better fuel economy pushed by both consumer and Environmental Protection Agency (EPA), made OEMs to put more effort on other areas beside vehicle external aerodynamics. As one of these areas, under-hood aero-thermal management has taken an important role in the new road vehicle design process, due to the combination of growing engine power demands, utilization of sophisticated under-hood and underbody devices, and emission regulations. The challenge of the under-hood aerothermal management is not only due to the complexity of under-hood compartment, but also as a result of the complex heat transfer phenomena involving conduction, convention and thermal radiation. In this study, 3D CFD simulations were used to investigate the under-hood aerothermal flow features. The full vehicle model with detailed under-hood components used in this study is a Hyundai Veloster. A commercial CDF code Star-CCM+ version 11.04 from CD-adapco was used to run all the simulations.

The radiator is the key component of a vehicle’s cooling system. The cooling effectiveness of a radiator largely depends on the flow of fresh air through it. Thus, at high vehicle speeds, the mass flow rate and flow-distribution or flow-uniformity over the radiator surface are the major operating parameters influencing the performance of a radiator. Additionally, the mass of air coming from the front grille plays an important role on the total drag of the vehicle. This paper presents computational studies aiming at improving simultaneously the efficiency of a radiator and reducing the total drag of the vehicle; this is achieved using passive aerodynamic devices that alter the flow pattern approaching the radiator. The vehicle model considered is a Hyundai Veloster and all analyses were carried out using a commercial CFD code Star-CCM+ version 10.04 by CD-adapco.

An innovative system has been developed to remotely monitor and record customer usage patterns of the Hyundai Genesis HVAC system in real time by smartphone. The data monitored includes dozens of HVAC-related parameters, including driver and passenger set temperature, blower setting, mode and intake position, internal software parameters, etc. This information and understanding of real-world usage of American customers enables design and test engineers to better satisfy customer demands for automatic temperature control performance. This study identifies areas in need of improvement Preliminary findings of this study suggest that auto mode usage is highest in mild temperatures and lowest in hot soaking conditions. In hot soak conditions (above 35C cabin temperature), the majority of American customers manually control the temperature and blower speed.

In an electric vehicle, a maximum cruising range is adversely affected by electric power consumption of auxiliary electric components for heating and cooling. Therefore, it is important for the air-conditioning to consume energy as efficiently as possible. This study describes how a proposed Occupied-Zone(OZ) HVAC system has attained a significant increase in the cruising range of an electric vehicle by air-conditioning occupied seats only. The idea of OZ HVAC is to confine air-conditioning to occupied-zones only. The OZ HVAC has an option of selectively air-conditioning three zones corresponding to driver, passenger and rear seating positions, while a conventional HVAC system air-conditions a whole cabin regardless of occupancy in each zone, which results in more power consumption compared to the proposed idea.

The development of an automatic defogging system using an accurate windshield humidity sensor and the existing HVAC hardware is described herein. Improved cabin temperature control and forward visibility for the driver was achieved using a sophisticated automatic defogging strategy integrated into the Automatic Temperature Control microprocessor. Laboratory tests were conducted under various weather conditions and test modes using a climate wind tunnel and field tests were conducted in North America The automatic defogging system worked well in all cases