Investigation On Control Strategy Of Injection Quantity And Calibration Of CR System For Diesel Engine

The CR-system is a brand new concept injection system. It can improve the character of the diesel engine , many meaures of which become the main access to improve the compressive charateristics, such as high pressure injection , and the flexible control of the injection pressure, injection timing and quantity, the injection rate and pilot injection multiple injection etc. The second-generation CR-system abonden the supply-system of the traditional engine, overtakes the faults such as supply depending on rotate-speed, and injection depending on the peddle, using the ways of combing time-pressure to control injection flexibly, improve the process of the conforming of the mixture, and lowing the PM and Nox emission, resolve the problem which confused for years.At present, in the purpose of fulfill the EUâ…¡, it is one of the eccessial ways to applying CR technology in diesel engine. CR has been seen as one of the three breakthroughs in the engine area in the 20's century, and can be the main stream of the diesel technology. Facing the strickt legislation, it can still be welcomed by the whole world.The paper combine one part of the subject which belongs Jilin Uni. names the development of the CR diesel for the CUV, the whole aim is based on the Bosch second-generation CR injection system, through the computering of the combustion-room, the designing of the structure, and optimising the parameters of the combustion through the experiments, make the CUV fulfill the emission calibration. For better proceeding the experiment, it is important to master the CR system control strategy. Although the market has imported and applied the CR system, but the research about which is few.It is necessary to understand the control strategy for mastering the CR tech. This paper did researches on the control strategy of the injection quantity, for the purposeof driving stedily, combining the state of the vehicular and the working condition of the engine, through the adjustment of the quantity controlling the output of the engine torque, balancing the driving power and the resistance, making the car going stedily finally. In which on the purpose of control torque to control quantity, is the key. Through principle and controlling theory, explain the inner torque of the engine, thought the dirct ratio relationship between the inner torqueand the quantity, enacting the quantity controlling MAP, so as to ensure the output torque controlling measure. During the normal working course, the inner torque and the quantity, has been liminated by the speed-charateristics. Considering the different working conditions such as speed and load, the normal working can be streatened, must enact some protecing ways, so as to control the driving charateristic accuratly.Though the analysis of the result of the experiment, following the rising of the quantity, the torque in the middle and high rotation speed area can achieve or even exceed the purpose, but has little effect in the low speed area, accoursing to the problem of dismatching between the engine and the turbo, pure calibration has limitation.Contrast the two MAP which applying in the experiment, can be seen the latter one has improve the driving characteristic but which fuel consumption and outlet temperature is higher, through combining the advantages of the two MAPs, can improve both the power characteristic ,the economical effeciency and the emission. During the calibration, raising the injection quantiy, and through raising the rail-pressure, enchancing the combine motion of the mixture, make the combustion better, so as to resist the PM, and delay the injection timing simultaneously to control the initial thermal releasing, the maximum temperature and the maximum pressure; in the area of 1600~1800r/min, for ensuring the torque in low speed, has enacted more injection quantity, so the combustion temperaure is higher, which raising the NOx emission, and the PM is low at the same time, so through low the rail-pressure, delay the injection timing to control the temperation and the pressure.This research is the beginning part of the whole subject, becouse of the time andequipment, many job has been waiting, belows are some of the shorts.During the pilot quantity and timing adjustment, the changing range is narrow, can be enlarged later, to contract and analyse the effect on the characteristic. The low speed characteristic still be gonging to improve. And the following task is to calibration the engine with EGR, through wich the injection parameters can be adjust properly, to achieve the optimize matching.