A DFSS Approach Study on the Effects of Vehicle Cabin Properties on HVAC System’s Cool Down Performance Using 1D Simulation 2020-01-1258

Due to the increase in heat wave across the globe, maintaining the thermal comfort of passengers in a vehicle is becoming a challenge. Considering global warming, there is a need to shift towards greener refrigerants which in itself causes a marginal degradation in the Heating Ventilation and Air Conditioning (HVAC) system performance. Also the emission norms and regulations demanding for a smaller engine if not for a hybrid or electric vehicle, there is a need for optimally designing the HVAC system since it is directly related with the efficiency of the vehicle and also plays a vital role in the customer comfort. Hence maintaining the comfort level of the passengers needs further exploration and challenging rather than optimizing the HVAC system alone in the competitive market. Conventionally for given system where we need sufficient cooling, the capacity of the components can be increased in order to meet the customer comfort. As cabin heat load plays vital role for the overall cabin cooling and considering fact that going for increasing capacity of the system will contribute more to the global warming, there is necessity to bring the thermal comfort in the cabin without increasing capacity of the system. Optimizing the cabin properties is one of the ways to bring thermal comfort in the cabin which is studied in this paper.

This study was conducted by considering the material properties and the areas of different components in the vehicle cabin like the windshield, side glasses, rear glasses, doors etc. By keeping HVAC system same, the contribution of each cabin component to the heat load of the vehicle cabin is studied. This was done using one dimensional (1D) simulation software Simcenter Amesim®. All the parameters which are important for the simulation are arrived using the DFSS (Design for six sigma) approach because it improves the quality and reliability. Input, output, noise factors and control factors for the study are arrived after few preliminary simulations and brainstorming. L18 orthogonal array was arrived using the different levels of control factors. The simulations outputs are analyzed using the DFSS methodology which identified the impact of the various control factors on the cabin cool down. This study helps us on understanding and deciding on the cabin components and materials during the concept phase for providing a better thermal comfort to the passengers.