VVT (Variable Valve Timing) control method capable of combining self-learning feed-forward and active anti-interference feedback

Abstract

The invention discloses a VVT (Variable Valve Timing) control method capable of combining self-learning feed-forward and active anti-interference feedback, which can improve the response speed of a VVT phase control, reduce the energy consumption of a regulating process and increase the adaptability to the operating environment change and the state change of an engine. The control method disclosed by the invention comprises the following steps of: carrying out a feed-forward control, an active anti-interference feedback control and a self-learning correction; regulating a hydraulic oil demand volume of a solenoid valve and a demand current I of a VVT solenoid valve through the feed-forward control; and obtaining a control signal It of a VVT system through the active anti-interference feedback control. The self-learning correction comprises the steps of concluding and calculating a characteristic parameter of the VVT system according to a VVT control quantity (a duty ratio of a PWM (Pulse Width Modulation) wave) and a response characteristic yr of the VVT system during the regulation of the VVT system so as to correct a calculating coefficient in a feed-forward controller model, thereby continuously increasing the calculation accuracy of the feed-forward control, improving the control capability of the feed-forward control, reducing the dependence on the feedback control and effectively improving the response speed and the accuracy of the control of the VVT system.

Description

technical field [0001] The invention belongs to the technical field of internal combustion engine control, relates to a variable valve timing mechanism of an internal combustion engine, and is a valve timing control system of an internal combustion engine, in particular a VVT control system with self-learning ability combining feedforward and active anti-disturbance feedback . Background technique [0002] Engine variable valve timing technology (VVT, Variable Valve Timing) is one of the new technologies that have been gradually applied to modern car engines in recent years. The variable valve timing mechanism (hereinafter referred to as VVT) can replace the traditional The valve timing mechanism is fixed to optimize the gas distribution action, which can provide the appropriate valve opening and closing time for the engine under the entire working speed and load range, thereby improving the engine intake and exhaust performance, and better solving the problem of high speed ...

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Problems solved by technology

[0006] (2) Non-linearity and time-varying parameters of the internal working process——Because the VVT ​​system is a hydraulic system with limited volume, it has its own natural frequency, which makes the VVT ​​system exhibit the characteristics of a nonlinear system during the motion process, especially At the end of the transition process, it is easy to cause the system to repeatedly oscillate; the pressure change of the hydraulic oil in the VVT ​​system is directly affected by the parameters of the VVT ​​system, such as oil pressure, oil temperature, battery voltage, etc., and these parameters are always changing during the engine running process, making it difficult to characterize the VVT ​​system

[0011] HCCI is very sensitive to changes in parameters. Whether it is in steady state or dynamic conditions, it puts forward extremely strict requirements on the accuracy, stability and speed of valve timing control. Currently, the widely used PID control On the one hand, the method has a contradiction between accuracy and rapidity. On the other hand, in the engine environment with many disturbances, the response to the deviation is slow, it cannot be effectively compensated, and the stability is poor, which can no longer meet the requirements of HCCI engine work.

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