Control Strategy And Calibration Study Of High Pressure Common Rail Diesel Engine For Complete Vehicles

Torque structure is an important part of control strategy of high pressure common rail electronic control system.Fuel-injection quantity per cycle in the system is influenced by variation of the torque,thus overall performance of the engine is affected as well.With the increase of on-board ECUs,engine ECU could be linked up to other ECUs using standard variables.Torque structure in control strategy should include not only torque of the engine,but coordinated control torque as well.It is of considerable realistic significance to coordinated control of engines and vehicles along with accurate control of injection quantity per cycle to investigate Torque structure in electronic control system of the engine.In order to integrate coordinated control of the vehicle performance into control of the engine,and to provide demand torque of the engine after coordinated control for fuel injection control strategy,torque structure was analyzed and investigated comprehensively.The investigation was carried out from two aspects:torque structure of the engine and overall vehicle.To be specific,torque structure of the engine includes coordination of protection torque?demand torque under idle and starting condition and total torque of the engine as well as analysis and modeling of transformation of torque into injection quantity.Torque structure of the vehicle mainly involves torque demands of drivers and coordination control of output torque of the engine by other ECUs on board,including coordination torque of vehicle transmission system and motion system along with torque of vehicle coordination system,which control and intervene demand torque of the engines in the main path based on control requirements of the vehicle.And ultimately,demand torque of the engine after coordination is obtained,which is transformed into oil injection quantity injected into the cylinder.Torque structure of the overall vehicle were validated by simulation.Then complete torque structure was jointed with injection and rail pressure control strategy,automatically generating code that was then downloaded into target controllers.Starting ability and idle running test along with acceleration and deceleration test were carried out.Also,key MAP data in control strategy was online calibrated.Simulation and experimental results show that:when output torque of the engine needs to be coordinately controlled,demand torque of the engines in the main path was intervened and controlled promptly and accurately by coordinated control torque of the overall vehicle.In addition,in the experiment,the engine features a quick start-up and was stable at idle.Good response performance and sufficient stability of the engine were obtained in acceleration and deceleration tests,which means the torque structure proposed in this paper is efficient and reasonable.