Study On Matching And Controlling Of Electric Charged Diesel Engine

As a kind of diesel engine charging technologies,turbocharger can greatly improve engine performance,decrease exhaust emissions,and reduce brake specific fuel consumption.It has been widely used in various vehicle diesel engines.While turbocharged engines have low speed torque shortages and turbo lags.The use of electric charging technology is an effective measure to solve these problems.The electric charging technology can aggressively promote the low-speed output of the engine,accelerate the transient response and improve economy.Firstly,based on the average parameter model,a matching calculation method between the engine and the turbocharger is established,which is applied to the selection of the turbocharger.The matching of the engine and the electric supercharger is carried out based on the energy matching method,and the compressor is adjusted according to the position of the joint operation line.Secondly,based on the improvement of the traditional turbocharged engine,an electric charged engine system is developed.The compressor is directly powered by the electric motor at the inlet,and the turbine drives the generator to recover the exhaust gas energy at the outlet.According to the demands of the electric charger,the type and parameters of the motor are determined,and the connection scheme between the motor and the electric charger is designed.Thirdly,the control strategy of the electric charged engine is designed.To control the output performance of engine,the motor power can be adjusted to control the charging capacity of the compressor at the intake end.The wastegate diameter is controlled to ensure that the electrical power recovered by the generator is below the maximum power.Lastly,turbocharged and electric charged engines are modeled with GT-Power software.,which can simulate engine operating processes based on engine heat transfer,combustion,flow,and control models.Comparing the simulation results of the engine with the matching calculation values,the error is within 5%,verifying the accuracy of the matching calculation method.Based on the characteristics of the electric charger ofrecovering exhaust gas energy,the concept of eBSFC is proposed to represent the brake specific fuel consumption of electric charged engine.Compare and analyze the performance difference between the two systems under four common operating conditions through GT-Power simulation results.Research shows that,the electric charged engine has stronger power output capability at medium and low speeds,better economy at medium and high speeds,and faster response under transient conditions,thus verifying the superiority of the electric charger system.