A Study On Simulation And Control Algorithm Of Electronic Unit Pump For Dimethyl Ether

DME is the optimal substitute for diesel to burn in diesel engine, which can solve effectively the crisis of energy resource and the pollution of environment. DME is of high cetane-value, which is beneficial for burning by pressing , and great performance of emission. Although there are some problems to be solved if we want to apply the DME on diesel engine. All the problems summed up are how to choose injection system, considering the merits of the DME as well as how to modulate construct parameters of the system to adapt to the fuel.At the same time , structure of EUP are simplified, and it is flexible to control the fuel injected and injection timing while fluctuation of timing is improved consequently. All these merits are helpful for the application of DME on diesel engine. So, in order to accelerate the process of research and developing of new system the characters of the injection system ,when the fuel is DME, should be discussed ,with combining simulation technical and pump test bench .Reforming advices and controlling strategies in general are also put forward on researching results.At first, the physical and chemical merits of DME are introduced, various of injection system for DME are analyzed and parameters of construct of needing to be changed when we appiv the fuel on these systems are summed up. Then both of the mathematic mode of EUP referring to the physical mode of the system and simulation program of the system by using the Matla/Simulink are set up when working principle and important parameters of EUP have been discussedWhen simulation program have been running, on the condition of altering the starting injection pressure when diesel is substituted by DME ,it is easy to get theresults of different working conditions which is including pressure wave of pump , needle lift in injector and fuel delivery per cycle ,etc. The study demonstrates that, while comparing with the results by using diesel in EUP, both of the maximum injection pressure and fuel delivery per cycle decrease largely;the curve of needle lift in injector is similar to the shape of triangle of which the rate of up and down is lower when fuel is DME;if the fuel is always the DME, there are obvious changing of injection character when diversifying the rate of area between pump area and injection orifice or the width of pulse to be input the solenoid valve or the speed of camshaft;when wanting to improve the performance of injecting process these parameters should be changed .We also compare the results of simulation with the the pump test bench taken by Zhang Yusheng in huangzhong university of science and technology .In addition the pump test bench of EUP with application for DME are designed.At last, we make up algorithm of EUP with application for DME including controlling methods in different working conditions including starting , idling , variable working condition together with the protecting condition of engine according as the discussed results both of the simulation and the experiment, and how to calculate fuel delivery per cycle and fuel injection timing in different working conditions . At the same time the MAP of fuel delivery per cycle and injecting timing are also partly manifested.