Research On Combustion Close-loop Algorithm Of Diesel Engine Based On Speed And In-cylinder Pressure

In today’s increasingly competitive field of commercial vehicles,the cost has been one of the most important factors for users to decide to buy the vehicles.For the purpose of improving the economic performance of diesel engine,DFCV conducted some technical studies and explored the technical feasibility of further promotion of fuel economy.One of those studies was the closed loop combustion technology studied on the hybrid pow er system.The system uses the mass production type electric heating plug cylinder pressure sensor as the feedback signal and fuel quantity and injection timing as control variables.The combustion equilibrium of each cylinder is improved effectively and accurate control the engine torque.However,the system need six cylinder pressure sensors,the cost is high.So I do one study to explore a low cost combustion closed-loop control scheme using one cylinder pressure sensor and engine instantaneous speed.A closed loop control system was built on a six-cylinder diesel engine.The core components of the system are two control units,one is iCAT(in-cylinder Combustion Analysis Tools)and the other is EECU(Engine Electronic Control Unit).The control algorithm make the IMEP and CA50 as the feedback variables and fuel quantity and injection timing as control variables.Through test the algorithm can realize the closed-loop control of two parameters.Based on the rigid model of engine crankshaft,the dynamics simulation research was carried out.The research shows the fluctuation of the instantaneous speed is the influence of the reciprocating inertia torque and the gas torque.In low and medium speed,gas torque is the main factor.The fluctuation of the instantaneous speed is the result of the torque of the gas.The instantaneous speed parameters were optimized,A closed loop control algorithm based on this instantaneous speed parameters was designed.Through the experiment,the difference between IMEP and instantaneous speed parameters was analyzed.IMEP reflects the indicated torque and instantaneous speed parameters reflects effective torque.But there is a strong linear correlation between the two parameters.The closed loop algorithm was designed based on IMEP and the instantaneous speed parameters and different algorithms were proposed for different applications.The effectiveness of the algorithm was verified in the application of hybrid power system,the results showed that the algorithm could realize the accurate control of torque based on a cylinder pressure sensor.