Abstract: The influences of the pressure relief valve (PRV) on the ventilation flow and the pressure in a vehicle passenger compartment were evaluated. Some numerical simulation of the flow field in the passenger compartment were carried out. According to the calculation results, the relationship between the opening area of the relief valve, the ventilation flow and the pressure in the passenger compartment was established. Combined with the passenger cabin inside air flow and pressure testing results, the equivalent openings and evaluation process of controlled leakage and uncontrolled leakage were established, the dynamic flow status and path in cabin and its influence on passenger comfort were analyzed based on the numerical simulation results. The results show that the leakage opening area and the pressure inside the passenger compartment, the pressure inside the passenger compartment and the ventilation flow vary according to the quadratic polynomial law. Combined with ventilation flow, pressure testing data and numerical simulation of flow field inside passenger compartment, accurate equivalent controlled and uncontrolled leakage openings can be obtained. Therefore, this method can be used to design relief valve and to evaluate the flow state and comfort of passenger compartment

Key words: vehicle passenger cabin, passenger cabin air quality, passenger cabin comfort, pressure relief valve (PRV), controlled leakage, uncontrolled leakage