Research of Pressure Control Based on Dither

The purpose of the paper is to study the impact of dither on how to improve the pressure control capability in common rail system. The dither is directly operating to the inlet metering valve and making the metering flow accuracy. The correlation between rail pressure and metering flow was analyzed. Optimizing the inlet metering valve control is to improve the pressure control. To overcome the hysteresis problem of the inlet metering valve and improve its stability and rapidity on the pressure control. The PID control strategy based on the pressure control were applied in the common rail system and many papers have introduced the logical. But the dither application was seldom introduced in the common rail system. The dither was specified for the inlet metering valve. With the proper dither signal, the stick-slip motion of the metering valve spool converted to a steady one and the dynamic performance was optimized. To verify the theoretical and calibrated the proper dither signal, the engine experiment test was scheduled. The test results showed that, the proper dither signal can improve the pressure deviation significantly in the common rail system.