Brake Assisted Engine Shutdown Control Method for Clutchless Hybrid Electric Vehicle

Abstract

The invention provides a method for controlling shutdown of an auxiliary engine of clutchless hybrid electric vehicle brakes. The method includes: if a vehicle meets the engine stop condition, calculating to acquire brake demand torque TB1 of a first brake, demand torque TE1 of a small motor and demand torque TE2 of a large motor through a vehicle torque distribution module under the condition that a second brake (B2) is opened; enabling the brake torque of the first brake to reach TB1 by adjusting current of a solenoid valve, and respectively sending TE1 and TE2 to corresponding small-motor controller and large-motor controller through a vehicle controller and controlling the corresponding small motor and the large motor to perform execution; allowing an engine to go into flameout, and when rotational speed of the engine is smaller than a first preset threshold A, locking the first brake (B1) by enlarging the current of the solenoid value through the vehicle controller to complete shutdown of the engine and allow the vehicle to go into pure electric mode. The method is simple and feasible, shutdown efficiency of the engine can be improved, and service life of the first brake can be prolonged.

Description

technical field [0001] The invention relates to the control field of hybrid electric vehicles, in particular to a brake-assisted engine shutdown control method for a clutchless hybrid electric vehicle. Background technique [0002] At present, hybrid electric vehicles basically use a combination of two power sources, the engine and the motor. In order to coordinate the work of the two power sources well, the vehicle controller needs to coordinate the output power of the two power sources at all times during the operation of the vehicle. In order to ensure that the entire power system is in a high-efficiency working state, when the battery SOC is high or the driver’s demand torque is small, the vehicle controller will issue an engine shutdown command, and it is necessary to control the engine shutdown to enter the pure electric mode. In order to ensure that the engine can be stopped quickly and Vehicle comfort, this process needs to be controlled to a certain extent. When th...

AI Technical Summary

Problems solved by technology

When the existing clutchless hybrid vehicle engine stops, because there is no clutch, the power connection between the engine shaft and the gearbox in the hybrid vehicle cannot be directly disengaged. In the prior art, the hybrid vehicle provides reverse torque through the motor to make the engine The speed drops until the engine speed is 0, but when the motor needs to provide a large reverse torque, the system will have an overpower problem, which will cause a large loss of electrical appliances in the vehicle, which is not conducive to the life of high-voltage accessories. Torque, and there is a problem that the engine flameout time is too long

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