Study Of Pressure Reducing Valve With An Asymptotically Closed Buffer Used In Automatic Shift System

Proportional electro-hydraulic valve is a key component in the powertransmission shift system to precisely control the clutch engagement pressure.Whether the proportional pressure reducing valve can precisely control the clutchengaged quickly and smoothly directly affect the shift quality of electro-hydraulicpower transmission shift system. In this paper, a new proportional pressure reducingvalve was developed to control the clutch engagement pressure precisely and reducethe instant impact of clutch engagement pressure. Therefore, the proportionalpressure reducing valve improved the stability of power transmission greatly, andhas shown the importance of improving shift quality.A pressure reducing valve with an asymptotically closed buffer is designed tosolve the problem of that the pressure shocks generated when the clutch frictionplate was engaged, which has not solved by foreign companies and domesticcompanies or high school. Clutch engagement pressure curves are obtained throughsimulation and experimental study respectively. The effectiveness of buffer istestified by the differences between clutch engagement pressure curves respectivelyproduced by the pressure reducing valve controlling clutch system with anasymptotically closed buffer and the system without.The main contents of this paper included: designing the proportional pressurereducing valve, developing gradually closed buffer. The tools used during theprocess of the design include Ansoft software, which is used to optimize theparameters of the proportional electromagnet, MATLAB, which is used tosimulation the operating characteristic curves of pressure reducing valve andoptimize the parameters of the pilot stage and the asymptotically closed buffer, andFLUENT, which is used to verify the feasibility of the buffer in practical work.The MATLAB model of proportional pressure reducing valve controlling theclutch system was built in this paper, which is used to simulate the clutchengagement pressure curves. Adding the asymptotically closed buffer to the system,the clutch engagement pressure curves were produced by the system to analysis thebuffering capacity.A buffer characteristics experimental platform was built in this paper, takingthe hydraulic cylinder as simulation load to obtain the pressure shock curves.Comparing the pressure shock curves of no buffer system and the pressure curves ofthe system with the buffer, the effectiveness of the closing buffer to reduce the pressure shock was verified.