Vehicle starting method and device

Abstract

The invention provides a vehicle starting method and device. The vehicle starting method is applied to hybrid electric vehicles. A vehicle comprises a rear shaft motor. The vehicle starting method comprises the steps that when the condition that a sand driving function of the vehicle is turned on is detected, the current vehicle speed of the vehicle is obtained; whether the vehicle is under a starting condition or not is judged according to the current vehicle speed; if the vehicle is under the starting condition, whether the rear shaft motor is under a locked-rotation state or not is judged;if the rear shaft motor is under the locked-rotation state, a preset control strategy corresponding to the sand starting function is executed; and the preset control strategy corresponding to the sandstarting function comprises the steps that the rear shaft motor is controlled to output torque by a preset torque gradient increasing method, and an electronic stability program (ESP) is controlled to increase rear-drive slip rate threshold. The potential safety hazard problem that in the prior art, a motor is burnt out due to the fact that the motor torque output is abnormal when the hybrid electric vehicle is controlled to start on sand by a traditional four-wheel drive mode is solved.

Description

technical field [0001] The invention relates to the field of automobiles, especially the field of hybrid electric vehicles, and includes a method and device for starting a vehicle. Background technique [0002] In order to meet the national vehicle emission reduction standards, electric vehicles and hybrid vehicles have become the main development trend of future vehicles. For hybrid vehicles, the driving mode is usually adopted. The power of the front axle comes from the traditional engine and its belt-driven starter generator BSG (Belt Starter Generator), and the rear wheel is driven by a motor. The motor power comes from a high-voltage battery pack. The battery pack can be charged by an external power source through an on-board charger, or it can be stored by BSG power generation and energy recovery during driving. Under normal circumstances, the hybrid electric four-wheel drive system of the above-mentioned drive mode can meet the driving requirements under certain off-...

AI Technical Summary

Problems solved by technology

[0003] In the prior art, most vehicles equipped with off-road working conditions are traditional mechanical four-wheel drive, which can achieve reasonable power output through a well-matched engine and transmission system, and at the same time realize 0%-50% of the front axle, The 50%-100% power distribution of the rear axle, but for the electric four-wheel drive control of the hybrid vehicle, the control principle of the mechanical four-wheel drive cannot be borrowed. When starting in this mode, the rear axle motor will be blocked due to excessive driving resistance and abnormal motor torque output, which will cause the vehicle to fail to start on the sandy ground and burn the motor.

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