Pure electric vehicle hill-start assist control method

Abstract

The invention discloses a pure electric vehicle hill-start assist control method. When in an uphill assist mode, whether a motor rotates reversely or not is detected, a vehicle slips reversely if the motor rotates reversely, needed additional anti-slip torque of the motor is calculated according to the reverse rotation speed and the accelerated speed of the motor, and the torque of the motor is increased until the motor no longer rotates reversely. When in a flat road assist mode, slip judgment is not performed. When in a downhill assist mode, the highest stable speed of downhill start is set according to a ramp angle, driving force generated by a ramp is calculated according to a vehicle weight sensor, needed parking torque is calculated, and a brake pedal opening value K corresponding to the parking torque is calculated. When the opening of a brake pedal is smaller than K, the start process is divided into a non-accelerator start mode and an accelerator start mode by judging acceleration pedal signals, and different start assist control is performed. Based on multi-sensor information fusion technology, the pure electric vehicle can stably, rapidly and safely start on the ramp by the aid of reasonable pure electric vehicle hill-start assist control strategies.

Description

technical field [0001] The invention relates to a control method for assisting start of a vehicle on a slope, in particular to a control method for assisting a start of a pure electric vehicle on a slope. Background technique [0002] The hill start assist control function is a control function developed to simplify the hill start operation. After the driver releases the brake pedal with his right foot, this function allows the vehicle to continue for a short time without using the handbrake. Keeping the braking state leaves time for the driver to switch from the brake pedal to the accelerator pedal, so that the driver can operate the pedal calmly and start the car easily. [0003] There are generally two types of electric vehicles in existence: a hybrid electric vehicle with a pure electric drive function and a pure electric vehicle. The pure electric vehicle cancels the engine and even the gearbox of the traditional car, uses the battery as the energy source, and the moto...

AI Technical Summary

Problems solved by technology

Although there are some methods for judging the situation of slipping forward in the prior art, they cannot be detected and prevented in time and effectively.

When the motor is in the parking state, if the accelerator pedal has not been pressed, the motor may be locked for a long time. When the accelerator pedal is pressed to start, the starting speed, acceleration and impact cannot be well controlled, and the start will be greatly frustrated.

In addition, the weight of the vehicle has a great influence on the force component of the slope, and the existing technology of auxiliary starting on the slope lacks the consideration of the weight factor of the vehicle

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