Hill start assistance method and device in snow mode

Abstract

The invention relates to a ramp starting auxiliary method and device in a snowfield mode. The method and device are used for solving the technical problem that a vehicle slides on a ramp in the snowfield ramp starting process. The method includes the steps that when it is detected that the control mode of a vehicle gearbox is the snowfield mode and the vehicle is located on the ramp, operation used for controlling the vehicle to be started is obtained; whether the wheel cylinder pressure of non-drive wheels of the vehicle is enough for making the vehicle stand on the ramp or not is detected; when the wheel cylinder pressure of the non-drive wheels is enough for making the vehicle stand on the ramp, the wheel cylinder pressure of drive wheels of the vehicle is released; traction torque is output to the drive wheels; and the wheel cylinder pressure of the non-drive wheels is released, so that the vehicle is driven to be started.

Description

technical field [0001] The present disclosure relates to the field of automobiles, and in particular, to a method and device for assisting a hill start in a snow mode. Background technique [0002] At present, most major car brands are equipped with automatic transmissions, and almost all automatic transmission vehicles are equipped with driving mode control systems. This control system can help drivers who are not familiar with special road characteristics. The driver precisely controls the vehicle to improve the driving comfort and passability of the vehicle. [0003] Currently, the most popular configurations of driving modes mainly include "Economy Mode (ECO)", "Sports Mode (SPORT)", "Snow Mode (SNOW)" and "Standard Mode (STANDARD)". [0004] Among them, "Snow Mode (SNOW)" is more suitable for urban roads covered with water, mud, grass, loose gravel or thin sand layers, and it is also used in special ice and snow environments. When starting on a snowy level road, if th...

AI Technical Summary

Problems solved by technology

[0006] (1) If the torque applied by the vehicle engine to the drive shaft is too large, although the ESP will respond to reduce the torque of the drive shaft, the response time is based on the wheel slip rate threshold, which means that it must reach the trigger threshold before it is triggered. Therefore, there will be a time difference in the snow mode control system

[0007] Within this time difference range, the drive shaft wheels and the snowy slope road may slip, and even the road surface is snowy before the wheels start (for example, the surface adhesion coefficient μ=0.3), after several times the driving wheels and the road surface After idling or skidding, the road surface is no longer a snowy road surface, but a mixed ice-snow road surface that looks like snow but not snow, and looks like ice but not ice (for example, the surface adhesion coefficient μ=0.1), causing the vehicle to start again at this time It will be more difficult, or even impossible to complete the snow slope surface start

[0008] (2) If the torque applied by the vehicle engine to the drive shaft is too small, although the snowy slope road surface does not turn into ice and snow, the drive shaft torque cannot provide the starting torque requirement of the vehicle at this time, and there is a possibility that the vehicle will slide down the slope, resulting in Accidents such as traffic accidents, property damage, casualties, etc.

[0009] It can be seen that under the current "snow mode", there is a problem that the vehicle may not be able to start normally from the snow slope

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