Closed-loop response method for natural gas engine torque

Abstract

The invention discloses a closed-loop response method for a natural gas engine torque. The closed-loop response method comprises the following steps: step I, in order to ensure the accuracy of calculation of the torque, a natural gas flow is accurately calculated, and a friction torque and the heat efficiency at each point of an engine are accurately calibrated; step II, after the engine receives the percentage of a command torque against a reference torque, the percentage is converted into the percentage against each rotational speed external characteristic indicated torque firstly; step III, a table is looked up to acquire a throttle opening degree table corresponding to the rotational speed and the load of the engine, and the engine outputs a throttle opening degree; step IV, an engine indicated torque at the time is calculated to obtain the percentage of the engine output torque; and step V, the percentage of the engine output torque is compared to the percentage of the command torque, and the throttle opening degree is regulated through PID control to enable the engine output torque to be consistent with that of the command torque. According to the closed-loop response method, the difference between the actual output torque of the engine and a torque command value is zero under the condition of generating variations on environment boundary condition of the engine.

Description

technical field [0001] The invention relates to the technical field of natural engines, in particular to a torque response method of natural engines. Background technique [0002] The accuracy of engine torque response of natural gas and electric hybrid vehicles has a great impact on gear shifting and vehicle performance. At present, the existing torque response methods are all open-loop responses, that is, after the engine receives a torque command, it responds to a fixed Throttle opening (throttle opening determines the intake air volume, fuel-air ratio and ignition angle), the output torque is not corrected according to the torque target value, so due to changes in the engine environment and boundary conditions, the engine output torque and The target value will deviate. This will lead to uneven gear shifting or even gear shifting failure. If the engine torque is used to limit the speed of the vehicle, the speed limit will fail, and other functions that use the engine to...

AI Technical Summary

Problems solved by technology

[0002] The accuracy of engine torque response of natural gas and electric hybrid vehicles has a great impact on gear shifting and vehicle performance. At present, the existing torque response methods are all open-loop responses, that is, after the engine receives a torque command, it responds to a fixed Throttle opening (throttle opening determines the intake air volume, fuel-air ratio and ignition angle), the output torque is not corrected according to the torque target value, so due to changes in the engine environment and boundary conditions, the engine output torque and The target value will deviate

This will lead to uneven gear shifting or even gear shifting failure. If the engine torque is used to limit the speed of the vehicle, the speed limit will fail, and other functions that use the engine torque will not work normally, which cannot meet the torque requirements of the vehicle for the engine, seriously affecting The drivability of the whole vehicle is not conducive to the matching of the engine

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