A current and pressure off-line learning method and testing system for a hydraulic automatic transmission

Abstract

The invention discloses an off-line current and pressure learning method and testing system of a hydraulic automatic transmission. During the learning process, the learning conditions need to be met, and the following steps are performed sequentially: performing current control on the clutch to be tested and other clutches to form a neutral gear; calculating the neutral gear Lower torque converter slip n CV0 ;Set the preset initial learning current; judge the torque converter slip under the current I output and the torque converter slip under neutral gear n CV0 Whether the difference is greater than the set threshold value within the set time period; calculate the current pressure parameter deviation ΔI of the clutch P2C = I R -I KP ;Calculate the current pressure characteristic parameter I of the clutch P2C = I deft +ΔI P2C , and stored in EEROM; it is not necessary to directly obtain the real pressure sensor signal, but indirectly through the load change of the clutch to reflect the change in the slip of the hydraulic torque converter, to compare and indirectly obtain the final current pressure characteristic parameters of the clutch , not only has high learning efficiency, but also eliminates some interference factors from the engine and transmission, which can make the learning results more real and stable.

Description

technical field [0001] The invention relates to an off-line current and pressure learning method of a hydraulic automatic transmission and a current and pressure testing system of a hydraulic automatic transmission. Background technique [0002] The hydraulic automatic transmission is a complex system integrating machinery, hydraulic pressure and electric control. The transmission is composed of more than 300 parts, and it has been performing rotational and linear motions throughout its life cycle. Therefore, with the mileage of the vehicle and the number of shifts of the transmission, the shift performance of the transmission will change, and the shift quality will deteriorate. Although the transmission control unit TCU generally develops an adaptive strategy, it is also automatically adjusted within a certain pressure range. Otherwise, it is easy to cause over-learning, which will also affect the shifting quality. For individual transmissions with extreme performance cha...

AI Technical Summary

Problems solved by technology

Although the transmission control unit TCU generally develops an adaptive strategy, it is also automatically adjusted within a certain pressure range.

Otherwise, it is easy to cause over-learning, which will also affect the shifting quality

For individual transmissions with extreme performance changes and relatively large performance attenuation, TCU's adaptive software cannot cover them and cannot guarantee good shifting quality

For this kind of transmission, it is technically feasible to directly obtain the current and pressure characteristic parameters of the transmission through the sensor equipment on the automatic transmission bench and write it into the TCU software, but the maintenance and testing costs of the transmission are very high Yes, and the cycle is very long, so it does not have the operability of after-sales maintenance

Images