Study On Shift Characteristics Of Dry Dual-Clutch Transmission

The clutch separation and engagement rule and the engine throttle opening control is the key technology of dual clutch transmission's shifting process.This thesis from the perspective of improving the shift quality of dual clutch transmission,to establish excellent shift control strategy to significantly increased its shifting performance.In this paper,there are six main working contents:1)Analyzed the structure characteristics,working principle of starting and shifting and dynamic flow of dry dual clutch transmission.2)The dynamics of clutch slip and lock conditions are deeply analyzed under the condition of accelerating shift and the low gear clutch negative zone slipping.By engine performance test,engine numerical model was established based on interpolation method.By analyzing the dynamics of vehicle accelerating state,establish the resistance moment of the vehicle model.3)As a instance first gear shift to second gear,qualitative analysis the relationship between the high gear clutch pressure increases and the low gear clutch transmission torque by theoretical analysis.Through the simulation calculation and experimental demonstration,confirmed the theoretical derivation,which lay a solid foundation for the development of the clutch pressure control strategy.4)As a instance first gear shift to second gear,the dry dual clutch transmission accelerating shift process are analyzed in detail.According to the working state of two clutch during shift process,the dual clutch transmission's shift process is divided into five stages.The dynamic equations of the system at various stages is deduced.Based on this,the dual clutch transmission Matlab/simulink simulation model of the whole process of accelerating shift is established.5)Analyzed the influence factor of shifting quality for dual clutch transmission vehicle.Based on the above dual clutch transmission Matlab/simulink model of the shifting process,through the simulation calculation,qualitatively analyzed the influence of various factors on the shift quality.Obtained a series of important conclusions.For example,under the condition of accelerating shift,if the greater engine throttle opening,the longer shift time and more friction work.But the throttle opening changes will not bring great influence on the shift jerk.Vehicle load changes will not bring great influence on friction work and the shit time.But the increase of vehicle load can significantly reduce the shift jerk.The shift jerk and friction work are sensitive to the change rate of clutch pressure.When the high gear clutch pressure time lag near the zero value,can obtain ideal friction work.Maximum shift jerk is caused by the low gear clutch negative zone slipping.6)Based on the analysis of the influence of the influence factor of shifting quality to shift jerk,friction work and shift time.New clutch pressure and engine throttle opening control strategy are proposed under the condition of accelerating shift and the low gear clutch negative zone slipping.Through the Matlab/simulink simulation analysis,the new shifting control strategy can significantly increased its shifting performance.