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In an effort to shorten and improve the efficiency of the product design process (PDP), Delphi has developed an application specific CFD design tool that helps design engineers optimize designs prior to prototyping. This new tool enables design engineers to set up an HVAC module, powertrain cooling system, or heat exchanger model for CFD analysis in relatively short time. The ability to evaluate and improve the design of the product at the very early stages of the development cycle greatly reduces the need for design changes late in the process, which are expensive and time-consuming. Besides reducing the design cycle, the new CFD tool has also reduced the model shop and testing expenses for each development project with fewer prototypes. In this paper, a case study for using this tool during the HVAC module development process in early stage is demonstrated.

Heating and cooling of automotive seats is a relatively new technology that delivers conditioned air to the occupant's seat providing an overall improvement in passenger comfort. This paper combines experimental and computational data to describe the effect of seat heating on passenger comfort. Included are: (1) a review of current seat heating technologies, (2) the introduction of an innovative seat heating technology using the vehicle's HVAC system, (3) the inclusion of thermal comfort seat strategy for improving overall comfort, and (4) validation of the thermal comfort seat strategy with experimental data. The paper focuses on the occupant's overall comfort in heating mode under different ambient conditions.

Heating and cooling automotive seats are a relatively new technology that delivers conditioned air to the occupant's seat providing an overall improvement in occupant comfort. This paper combines experimental and computational data to describe the effect of seat cooling on occupant comfort. Included are (1) a review of current seat cooling technologies, (2) the introduction of an innovative seat cooling technology using the vehicle's HVAC system, (3) the inclusion of thermal comfort seat strategy for improving overall comfort, and (4) validation of the thermal comfort seat strategy with experimental data. The paper focuses on the occupant's overall comfort in cooling mode under different ambient conditions.

Simulation of cabin climatic conditions is becoming increasingly important as a complement to wind tunnel and field testing to help achieve improved thermal comfort while reducing vehicle development time and cost. Delphi developed the Virtual Thermal Comfort Engineering (VTCE) process to explore different climate control strategies as they relate to occupant thermal comfort in a quick and inexpensive manner. The comfort model has the ability to predict the local thermal comfort level of an occupant in a highly non-uniform thermal environment as a function of air temperature, surrounding surface temperatures, air velocity, humidity, direct solar flux, as well as the level of activity and clothing type of each individual.

Delphi Harrison Thermal System's comfort model can be used to predict the local thermal comfort level of an occupant in the highly non-uniform thermal environment of a vehicle cabin. This model is based on the concept of Equivalent Homogeneous Temperature (EHT) to assess the local comfort of 16 body segments as a function of air temperature, surrounding surface temperatures, air velocity, humidity, direct solar flux, as well as the level of activity and clothing type of each individual. Although EHT has been accepted by some European automotive industries, OEMs in North America have their own comfort scales. In the present study, we developed a model to correlate our EHT scale to an OEM's comfort scale. The current comfort model based on EHT produced excellent agreements with human subject data based on an OEM's comfort scale for both summer and winter rides.

Simulation of passenger compartment climatic conditions is becoming increasingly important as a complement to wind tunnel and field testing to help achieve improved thermal comfort while reducing vehicle development time and cost. Thermal analysis of a passenger compartment involves not only geometric complexity but also strong interactions between airflow and three modes of heat transfer, namely, heat conduction, convection, and thermal radiation. The present full 3-D CFD analysis takes into account the geometrical configuration of the passenger compartment including glazing surfaces and pertinent physical and thermal properties of the enclosure with particular emphasis on glass properties. This CFD analysis is coupled with a thermal comfort model in the Virtual Thermal Comfort Engineering (VTCE) Process that was described in [1].

Simulation of passenger compartment climatic conditions is becoming increasingly important as a complement to wind tunnel and field testing to help achieve improved thermal comfort while reducing vehicle development time and cost. Delphi Harrison Thermal Systems has collaborated with the University of California, Berkeley to develop the capability of predicting occupant thermal comfort to support automotive climate control systems. At the core of this Virtual Thermal Comfort Engineering (VTCE) technique is a model of the human thermal regulatory system based on Stolwijk’s model but with several enhancements. Our model uses 16 body segments and each segment is modeled as four body layers (core, muscle, fat, and skin tissues) and a clothing layer.

This paper chronicles a heat exchanger development project that utilized an integrated development process. A combination of full-scale heat exchanger performance testing, flow visualization experiments, and computational fluid dynamics methods were used in concert to investigate flow phenomena in multilouver fins. The primary goal of this project was to confirm the flow and heat transfer enhancement mechanisms at work in multilouver fins. A second goal was correlation of flow visualization, CFD, and traditional full-scale heat exchanger testing. Excellent agreement was found between the three methods.