Research and applications for control strategy of high-pressure Common Rail injection system in diesel engine

Abstract

To reduce combustion noise significantly and improve torque curve a new control strategy is presented. The new control strategy is based on solenoid-valve-controlled high pressure common rail (CR) injection system, which is one in which the high injection pressure is available at all times and not only during the injection periods. The system layout, which includes high pressure pump, rail and pipes, injector, ECU, and sensors, is drawn and every part is described in detail. Three control functions are carried out: rail pressure set point, rail pressure control and rail pressure monitoring. In addition, a block diagram of the high pressure control function is shown. Finally, a few applications are made: low pressure system with filtering, design of a CR system by simulation, and rail pressure. Besides, start- times controlled by CR system and by conventional high distributor pump (VP44 and VP37) are compared. Finally, schematic of the test bench configuration and engine specification are showed. Cylinder pressures and the corresponding heat release rates with variation of injection timing are compared with experimental data. It gives the theory and method about control strategy exactly in directed-injection diesel engine.