A method for controlling engine startup of a hybrid electric vehicle

Abstract

The invention relates to a hybrid electric vehicle engine starting control method. When an engine receives a starting instruction during forwarding, if the rotation speed of the engine is larger thanthe minimum starting rotation speed of the engine, the engine sprays fuel for ignition and enters a rotation speed control mode, wherein the target rotation speed is the rotation speed of a motor, a coupling mechanism clutch remains a separated state, and the target torque of the motor is the demand torque of a driver. When the rotation speed difference between the motor and the engine is lower than a first preset value, the engine continues to maintain the rotation speed control mode, and the coupling mechanism clutch is in a semi-engaged state. When the rotation speed difference between themotor and the engine is lower than a second preset value, the coupling mechanism clutch is gradually fully-engaged to be in a locked state according to a certain rate; meanwhile, the engine is switched from the rotation speed control mode to the torque control mode, and the target torque of the engine is gradually changed to the demand torque of the driver. After the torque of the coupling mechanism clutch is greater than a preset lock value, the starting process is finished. Towing of the motor is not needed, the engine is started, and the starting time of the engine is shortened while the smoothness is ensured.

Description

technical field [0001] The invention relates to a method for controlling the starting of an automobile engine, in particular to a method for controlling the starting of a hybrid electric vehicle engine. Background technique [0002] Hybrid vehicles are usually equipped with two power devices, the engine and the motor, and the powertrain control system coordinates the orderly work of the two. When the power demand of the car is large or the battery power is low, it is necessary to connect the engine quickly and smoothly so that its output torque can participate in the driving. When the vehicle's power demand decreases, it is necessary to quickly and smoothly exit the engine, stop it from running or keep it at idle speed. Therefore, the start-stop control of the engine is the focus and difficulty of hybrid electric vehicle control. [0003] For single-motor hybrid systems, according to the position of the motor relative to the traditional power system, single-motor hybrid so...

AI Technical Summary

Problems solved by technology

For the situation where the stop process changes its mind and needs to be restarted, if the above-mentioned motor-to-engine control method is still used, unnecessary dragging energy waste and unnecessary clutch slip wear loss will be caused, and the start-up process time will be increased.

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