Natural gas engine torque control method and system

Abstract

The invention provides a natural gas engine torque control method and system. The method comprises the steps that a gear shifting control instruction is received; whether the control instruction is a torque limiting instruction or a torque control instruction is judged, a target value of an engine torque closed loop is determined according to a judgment result, and engine target torque is obtained; according to comparison of the target torque of the engine and the actual torque of the engine, it is determined that the engine is in the torque returning stage in the gear shifting process; in the torque returning stage, the engine torque is controlled with the offset torque of the engine as a target value of engine torque closed-loop control; wherein the offset torque of the engine is equal to the sum of the target torque of the engine and a calibrated offset value; by optimizing the PI closed-loop formula, the target torque of the engine is shifted, the actual torque output of the engine can be increased in the initial torque returning stage, and the problem that the torque response of the natural gas engine is slow is solved.

Description

technical field [0001] The invention belongs to the technical field of engine control, and in particular relates to a natural gas engine torque control method and system. Background technique [0002] The demand for electronically controlled mechanical transmission (AMT) for vehicles is increasing year by year. At the same time, customers have put forward higher requirements for shifting comfort. As an important part of commercial vehicles, natural gas engines have greater challenges. Six natural gas engine fuel control is premixed combustion and equivalent combustion. The fuel injection amount is calculated based on the throttle valve opening. After passing through the intake pipe, it enters the cylinder and performs direct injection in the cylinder relative to the fuel of the diesel engine. The natural gas engine has a large torque response delay. . [0003] The inventor found that when the engine performs normal PI control (proportional and integral closed-loop control),...

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Problems solved by technology

[0003] The inventor found that when the engine is under normal PI control (proportional and integral closed-loop control), the engine is in the initial stage of the twisting phase, and the torque difference is relatively small. The actual torque output of the engine calculated by PI is small, and the delay of the natural gas engine itself is relatively large, resulting in poor torque response of the engine

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