Oil pre-filling control method for wet clutch in hybrid power transmission

Abstract

The invention provides an oil pre-filling control method for a wet clutch in a hybrid power transmission. When the clutch is started, an oil path of the clutch keeps the state that the oil path is filled with oil, when oil needs to be prefilled into the clutch, the rotating speed of an oil pump does not change, a whole vehicle controller controls the current of a solenoid valve of the clutch to rapidly increase to I1, then the whole vehicle controller controls the current of the solenoid valve of the clutch to rise to I2 according to the gradient deltaV, and the pressure of the high pressure oil in a piston starts to rise; and when the thrust generated by the high pressure oil exceeds the resistance of a return spring, the piston of the clutch is started to be pushed to move, when the distance of movement of the piston of the clutch reaches a preset value A, the whole vehicle controller controls the current of the solenoid valve of the clutch to decrease to I3 from I2, the pressure ofthe clutch is decreased to a kisspoint point, and the position of the piston of the clutch is maintained unchanged. The method is simple and feasible. By optimizing the current increase curve of the solenoid valve of the clutch, the peak demand for the flow in the oil pre-filling process of the clutch is reduced, and the system efficiency and reliability are improved.

Description

technical field [0001] The invention relates to a method for controlling pre-filling oil of a wet clutch in a hybrid transmission. Background technique [0002] The normal operation of the gearbox usually requires the hydraulic system to provide high-pressure oil and low-pressure oil at the same time. The high-pressure oil is mainly used for the control of the clutch, and the low-pressure oil is mainly used for the lubrication of the bearings and gears, and the cooling of the clutch. The oil pump of the transmission needs to meet the flow requirements of high-pressure oil and low-pressure oil at the same time. The high-pressure control flow and low-pressure cooling flow are only in great demand under certain working conditions, and the demand for other working conditions is small, while the demand for low-pressure lubrication flow continues to exist. And the range of change is small. The maximum required flow of high-pressure oil occurs during the short process of clutch pr...

AI Technical Summary

Problems solved by technology

However, it takes a certain amount of time to increase the speed of the electric pump. If the adjustment of the speed of the electric pump is completed first and then the pre-filling of the clutch is performed, the shift time will be significantly increased. If the flow rate is insufficient, the pressure of the main main oil circuit will drop, which in turn will cause the pressure of other lock-up clutches to drop, resulting in slipping, and it is difficult to balance economy and reliability.

[0006] In the prior art, in order to meet the demand for flow during the clutch pre-filling process and reduce the pressure drop of the main main oil circuit, the gearbox usually has three solutions. The first is to always maintain a large flow. This method The disadvantage of this method is that it will reduce the efficiency of the system. The second is that when shifting gears, first increase the speed of the electric pump and then shift gears. The disadvantage of this method is that it will increase the shifting time and reduce the response to driving intentions. The third The first is to increase the speed of the oil pump for a period of time in advance. The disadvantage of this method is that it will also reduce the efficiency of the system. In addition, after the speed of the oil pump is significantly increased, it will cause noise problems.