Electric parking brake (EPB) control method for electric car

Abstract

The invention relates to the field of vehicle automatic control and in particular relates to a parking brake control method. An electric parking brake (EPB) control method for an electric car is characterized by carrying out following control after setting the delay time: from a driving state to a parking brake lock state, firstly carrying out lock operation on a vehicle by using an EPB system, waiting for the delay time and then sending a parking brake signal to an electric parking pawl (EPP) system by a vehicle control unit to carry out lock operation on the vehicle; and from the parking brake lock state to the driving state, firstly controlling the EPP system to be unlocked by the vehicle control unit after a brake pedal is depressed, waiting for the delay time and then unlocking the EPB system. The method has the beneficial effects that the reliability of the EPP system is improved by starting the EPB and EPP systems in sequence, thus avoiding seizure of the EPP system under the full load condition or the long ramp condition and eliminating abnormal sounds produced by parking on the short ramp and unlocking under the full load condition; and meanwhile, parking and unlocking can be smoothly carried out under the long ramp condition, thus improving the reliability of vehicle control.

Description

technical field [0001] The invention relates to the field of vehicle automatic control, in particular to a parking control method. Background technique [0002] EPP is the abbreviation of Electric Parking Pawl, the Chinese name is electronic parking pawl, including wheel shaft gear, pawl and parking cam, the parking cam is equipped with a cam spring, and the pawl is equipped with a return spring; Parking: rely on the small motor inside the EPP to drive the parking cam to rotate, and the parking cam pushes the pawl into the tooth gap of the wheel rotating shaft gear to realize parking. The pawl reacts on the cam, the cam spring is compressed, and the cam angle remains unchanged. Waiting for the rotation of the rotating shaft gear, the pawl waits for an opportunity to snap into the gear gap to realize parking. Unlocking: Rely on the motor to reversely rotate a certain angle, so that the cam returns to the initial position, and the pawl withdraws from the tooth gap under the a...

AI Technical Summary

Problems solved by technology

When parking and braking, the EPP motor needs to generate enough torque to forcibly engage or disengage the locking mechanism, so the EPP parking system alone cannot achieve the purpose of unlocking, or even though the unlocking is achieved, it will cause a large abnormality ring

While only using the EPB system, although the abnormal noise will be much smaller, the parking effect will be much smaller than that of the EPP system. When the slope is large, it is easy to slip backwards

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