A Study of Passenger Car Cabin Pre-Ventilation under the Sun

Abstract

With the increasing intelligence of automobiles, vehicle pre-ventilation can be better controlled. In summer, cars parked in the open air are directly exposed to sunlight; thus, a high-temperature environment is formed in the occupant cabin, which seriously affects the passengers and driver’s riding and driving experience. Meanwhile, lowering the temperature of the passenger compartment from a very high temperature to a comfortable temperature consumes a lot of energy. Therefore, it is increasingly important to study the pre-ventilation of the cabin in order to improve the thermal comfort of the occupant cabin and reduce energy consumption. In this paper, a new theoretical model of a cabin temperature control system is proposed. To support the theoretical model, an outdoor parking temperature rise test was carried out. Environmental parameters were obtained and used as the boundary conditions of the subsequent simulation. Based on the mechanism of the cabin temperature rise, the convective heat transfer coefficient on the body surface, the equivalent heat transfer model of the cabin, the solar radiation model and the physical properties of the air, a computational simulation of the temperature rise in the occupant cabin was carried out, and a simulation of the temperature rise in the occupant cabin exposure was studied. The simulation results were compared with the experimental findings to verify the accuracy of the simulation, which provided a reference for the design of the pre-cooling function of the occupant cabin. This study revealed that the pre-ventilation model developed reduces the vehicle cabin temperature through optimal control of air supply volumes and air supply angles. Furthermore, the developed pre-ventilation model is capable of reducing energy consumption, thereby reducing greenhouse gas emissions.