Anti-Noise PI Controller with Inner Loop Feedback for Pressure Control of High-Pressure Common Rail

High-pressure common rail fuel systems are widely used in internal combustion engines. The common rail is a nonlinear time-varying system essentially, which may cause huge fluctuations in common rail pressure. In this paper, an anti-noise proportional-integral (PI) controller is designed. Its integral term is loop-locked and can give feedback. Thus, the pressure fluctuation is directly related to the integral coefficient. At the same time, the integral term can be separated from the controller, which can effectively maintain pressure stability in extreme circumstances. After the above treatment, the saturation phenomenon of an integral part is effectively suppressed. The common rail pressure is also stabilized. The influence of integral saturation is analyzed on common rail pressure. In the simulation process, the proposed anti-saturation PI control scheme is simulated under different control objectives and operating conditions, and compared with other control schemes. It is shown that the proposed control scheme has a remarkable effect.