Method and device for controlling engine of hybrid electric vehicle

Abstract

The present application discloses a method for controlling the engine of a hybrid electric vehicle. For a direct-connected hybrid electric vehicle, in the process of starting or stopping the engine, the position of the crankshaft when the intake valve is closed when the engine is running normally is called the first reference position. The crankshaft position when the exhaust valve is opened is called the second reference position; in the process of starting or stopping the engine, an additional period of opening time is added for the exhaust valve; the starting point of the additional opening time is at the first reference position at the crankshaft position Within the range of 5 degrees before to 30 degrees after, the end point of the additional opening time is within the range of 30 degrees to 0 degrees before the crankshaft position is located at the second reference position. Under the premise of not affecting the normal operation of the engine of the direct-connected hybrid vehicle, the application greatly overcomes the vibration during the starting and stopping process, improves the riding comfort, and can further reduce the torque impact during ignition.

Description

technical field [0001] The present application relates to an engine control method of a hybrid electric vehicle. Background technique [0002] There is a kind of hybrid vehicle that does not have separation mechanisms such as clutches, and its engine is directly connected with the transmission system. For this direct-connected hybrid vehicle, when the engine starts or stops according to the instructions of the controller, the engine will vibrate violently at low speed, which will produce obvious vibration impact on the whole vehicle, seriously affecting the ride comfort. This problem is documented in SAE (Society of Automotive Engineers International) paper "Noise and Vibration Reduction Technology in Hybrid Vehicle Development" published on April 30, 2001 with number 2001-01-1415. [0003] see figure 1 , After the direct-connected hybrid vehicle is powered on, the motor drives the engine to run first, the engine speed gradually increases, and then the ignition is carried ...

AI Technical Summary

Problems solved by technology

Compared with ordinary Otto cycle engines, the Atkinson engine with the same displacement has the disadvantages of more torque drop and reduced power output of the engine, which deteriorates the vehicle's acceleration and fuel consumption at high speeds.

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