A kind of adjustment and control method of wet dct clutch oil filling process

Abstract

The invention relates to the field of wet dual-clutch automatic transmissions, in particular to a method for regulating and controlling the oil filling process of a wet DCT clutch, which comprehensively considers the influence of factors such as hydraulic system hardware consistency, ambient temperature and other factors on the driving performance of a solenoid valve, and optimizes a current control strategy The phenomenon of pressure overshoot and pressure underfill caused by the fixed oil filling time. By setting the clutch pressure response reference time, monitoring the actual clutch pressure in real time, calculating the actual clutch pressure response time, realizing the self-adjustment function of the oil filling time during the oil filling process, and optimizing the problem of poor pressure control consistency caused by the difference in the response time of the clutch solenoid valve, Improve the vehicle crawling condition caused by pressure overshoot, drag down the engine speed or even stall, start stutter, static switching PRND shift shock, upshift shift shock or pressure follow overshoot caused by pressure undercharge, slow creep response , start stumbling, power output lag and other technical problems.

Description

technical field [0001] The invention relates to the field of wet dual-clutch automatic transmissions, in particular to a method for regulating and controlling the oil filling process of a wet DCT clutch. Background technique [0002] The clutch of wet DCT (dual clutch automatic transmission) is powered by a hydraulic system including a solenoid valve, and sends an oil charge command (current signal) through the transmission control unit to the solenoid valve that controls the output pressure of the clutch. The PI characteristic (that is, the corresponding relationship between pressure and current) moves the spool to open the oil circuit of the hydraulic system, and controls the amount of hydraulic oil in the hydraulic system entering the clutch piston cavity to control the output pressure of the clutch, thereby realizing the combination of the clutch to transmit torque. [0003] The process in which the transmission control unit sends an oil filling command to control the mo...

AI Technical Summary

Problems solved by technology

[0005] The existing drive control scheme for the oil filling process of the clutch does not take into account the consistency of the hardware, so the control accuracy is bound to be inaccurate, and it is extremely difficult to control the output pressure corresponding to the clutch semi-linkage state (kisspoint). The influence of ambient temperature is great, and it is very easy to undercharge or overcharge the clutch pressure, resulting in many problems as follows:

At this time, the clutch has not started to transmit torque. If the clutch pressure increases to transmit torque, it will produce an impact. In addition, because there is hysteresis in the process of clutch oil filling, the clutch will start to increase the output pressure of the clutch before it reaches the semi-linkage state, which will cause the clutch If the pressure following control is not good, it will also produce impact

[0008] (2) When the actual delay response time of the solenoid valve is shorter than the reference delay response time, there is a risk of pressure overcharge, which will lead to a longer duration of the clutch oil filling process, which will cause static switching PRND shift shock, vehicle crawling and dragging Low engine speed or even flameout, starting frustrating, up / down gear shifting impact, etc. These situations are especially obvious at low temperatures

[0010] Moreover, during the operation of the hydraulic system, the delayed response time of the solenoid valve is affected by the viscosity of the transmission fluid and the consistency of the hardware. Especially in low temperature environments, the delayed response of the clutch solenoid valve for the first few times after the vehicle is cold started The time difference is very large, and the difference in the response of the solenoid valve can easily cause the problem of inconsistent oil filling pressure control, which reduces the stability and consistency of the clutch oil filling process.

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