Modeling And Experimental Verification Of Key Brake Components Of Pneumatic Brake System In Passenger Car

The pneumatic brake system takes the advantage of simple structure andlarge braking-force. But the braking process of pneumatic brake system ismulti-variable, complex nonlinear and strong-coupling. The requirement of the brakesystem demands to consider the transient pressure response, If only studying thestatic characteristics, the analysis results may be much different from the actualsituation. Therefore, researching on the dynamic response characteristics of thepneumatic brake system is necessary. The braking performance of system isdetermined by the performance of key braking components and the relationshipbetween the braking components. Therefore, the dynamic characteristic of pneumaticbrake system needs to be researched from two aspects. One is the dynamiccharacteristics of the key braking components; the other is output matching abilitybetween the braking components.In this paper, the dynamic response characteristics of the brake valve, relayvalve and chamber were studied. First, the safety requirements and evaluation ofpneumatic brake system was analyzed. The equations of flow, temperature, pressureand motion-governing were derived. Second, the full-parameter models of pneumaticbrake system and its key braking components were established based on pneumaticmodeling theory by the multi-domain modeling software-AMESim. The dynamiccharacteristics of brake system and its key components were simulated and analyzed.The influence factors of dynamic response and the output-matching relationshipbetween the key braking components were also studied by simulation. Finally, atesting system of pneumatic brake system was developed, and the dynamic responsetime of brake system and its key braking components was tested. The accuracy ofmodels were verified by comparing the simulation results and experimental results.The comparison results show that the models of brake valve, relay valve andbrake chamber is accurate and reliable. The simulation results could well explain thebraking response. The curves of simulation results were in line with experimental results. For the deviation, the explanation and analysis were also given. Thesemodels could provide data support for structural optimization of brake componentsand matching evaluation of the pneumatic brake system. It also lay the foundation forfurther research about brake system.