Observation and compensation of coupling effects between oil pressure and rotation speed of Variable Valve Timing System in Gasoline Engine

The stability and disturbance rejection ability of the electro-hydraulic Variable Valve Timing (VVT) system make great influence on the performance of gasoline engine. The coupling effect between oil pressure and rotation speed of Variable Valve Timing System in Gasoline Engine is the main factor that affects VVT system´s behavior in steady mode. This coupling effect greatly changes the operation conditions of VVT system in a short time when the rotation speed changes. Meanwhile, it is hard to calibrate since it´s determined by the engine structure, temperature and aging effect. These difficulties can´t be well solved by classical linear controller. Based on active disturbance rejection concept, the liner ADRC controller is proposed in this paper to observe the coupling effect as a disturbance and compensate it. The experiment results demonstrate that compared to classical PID algorithm, the liner ADRC controller shows much stronger disturbance rejection ability by observe and compensate the coupling effect in advance, thus bringing higher accuracy and stability to VVT system in steady mode.