Study On A Diaphragm Vacuum Pump For Automobile

In recent years, with various countries paying more attention to environmental protection and energy saving, gasoline direct injection engine, hybrid and pure electric vehicle gain more development, and the technology out of fashion leads to failure of some parts function. For example, instead of the engine intake manifold, the vacuum pump plays an main role in the vacuum source of a car vacuum booster brake system. The vacuum pump in this paper is a diaphragm vacuum pumps for automobile, which belongs to dry vacuum pumps and has the advantages of good sealing performance, long durability, small vibration and low noise. Though its manufacturing cost is high, it will play an important role in the future of the medium and high-grade automobile parts market.Based on the vacuum engineering technology and the finite element theory, this paper takes a diaphragm vacuum pump as the object of study, and a series of issues for pumping performance prediction, structure optimization of key parts and performance promotion, are investigated. The major studies can be summarized as follows: based on the structure of diaphragm vacuum pump, its working principle and gas state change are studied; The mathematic model for pumping performance of a diaphragm vacuum pump is presented on the basis of the state of inlet and exhaust; the working volume in the mathematic model for pumping performance is calculated in the way of coombining finite element analysis with constrained delaunay triangulation; the calculation data is compared with the experiment, and the comparison is used to verify the rationality of the mathematic model for pumping performance; the structure of the diaphragm and pump body are optimized in considerating of strain distribution in diaphragm.The vacuum achievement time and the variation of vacuum with pump time are employed to evaluate the pumping performance of the diaphragm vacuum pump. Corresponding performance test is conducted to verify the proposed model and calculation approach. A good agreement between the test results and the calculated results is achieved. It concludes that the presented model is capable of characterizing the pumping performance with reasonable accuracy. The proposed calculation method can facilitate the design of any vacuum pumps in terms of optimization, shortening develop time and saving cost.