Neutral gear control method for automatic transmission

Abstract

The invention provides a neutral gear control method for an automatic transmission. The method comprises the following steps that when the neutral gear control function of the automatic transmission is in an activated state, an automatic transmission control unit collects the information including the pressure of a braking main cylinder, the state of a braking pedal and whether the automatic parking function is in the activated state or not. When the pressure of the braking main cylinder is smaller than the pressure threshold value P3 of the neutral gear control function and the automatic parking function is in a non-activated state or when the braking pedal is in a non-stepped state and the automatic parking function is in the non-activated state, the automatic transmission control unit controls the neutral gear control function to retreat from the activated state.

Description

technical field [0001] The invention relates to the field of automobile control systems, in particular to a neutral gear control method of an automatic transmission. Background technique [0002] In the prior art, in order to reduce the fuel consumption of the vehicle and improve the NVH (Noise, Vibration, Harshness) performance of the vehicle, more and more vehicles are equipped with automatic transmission neutral control Function, the automatic transmission control unit (Transmission Control Unit, TCU) controls the linear pressure sensor inside the transmission so that when the vehicle is in the D gear (Drive, forward gear), when the driver steps on the brake and the brake master cylinder pressure reaches a certain value, Make the automatic transmission in the neutral state, and the power output of the engine is disconnected; when the driver releases the brake, the brake master cylinder pressure will be close to 0Kpa at this time, which no longer meets the requirements of ...

AI Technical Summary

Problems solved by technology

[0005] First of all, when the driver steps on the brake pedal in the D position of the car, the automatic parking function and the neutral control function of the automatic transmission will be activated at the same time, but the automatic parking function is designed to release the driver's right foot and improve the driver's driving For comfort, if the driver releases the brake pedal, the automatic parking function will still keep the wheels braked, but the neutral gear control function will exit, and the engine will output power. At this time, the neutral gear control function will no longer be able to improve the fuel consumption of the vehicle. and NVH performance

[0006] Secondly, when the neutral gear control function exits, the vehicle tends to drive because the engine outputs power outwards, but at this time the automatic parking function brakes the vehicle through the wheels to make the vehicle stationary, which will increase the vibration of the vehicle. Larger, poorer comfort performance, and higher fuel consumption

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