| As the regulations of emission constantly improve, energy become tense. The reduction of emission and fuel consumption, the improvement of power become more and more important to diesel designing, also the diesel factories are facing such major problem to solve.In recent years, people used a variety of methods but have no best results. General bypass valve supercharger in the diesel engine emissions and power performance, albeit temporarily eased, it can not control its operation of the diesel in the whole improved but only take care of specific aspects in controlling , and no substantive improvement. With the development of science and technology, the variable nozzle turbocharger(VNT) improve the previous supercharger of bypass valve, it is equipped with an adjustable nozzle ring by changing the blades of supercharger, which can totally control the diesel. It can fit the very moment when the air is inadequate in low-speed and also fit the requirement of high-speed and high-pressure. But it is difficult to ensure that the diesel VNT control precision which is facing problem as fast response and high accuracy of engine factories.Base on the item researching of the diesel characteristics and fearures, in order to designing one requirement of the diesel electric control unit,In the software of the VNT controlling used the incremental PID arithmetic and transient controlling,filter arithmetic and so on. In the designing of hardware ,both of controlling circuit and power circuit were rigorous tested by us.The five major research of the paper as below:The first, analyze the VNT system and EGR system in internal and external;The second, introduce how do the VNT system and EGR system consist of ;The third, Design the hardware which use in VNT system and EGR system and how to choose the peripheral sensors;The fourth, Analysis according to the flaw of control of diesel system, design a suitable arithmetic of VNT system and EGR system;The fifth, experiment at the Dalian Diesel Factory and gas engine lab of Jilin university, improve the parameter in control software and calibrate the optimal MAP; finally through the experiment test and road test validate the VNT system and EGR system effect on the increasing power, decreasing the consumption of fuel and emission of diesel control;The final analysis result through the test data:Engine test system and application of VNT system diesel fuel consumption is reduced by 5% and smoke reduced 20% to 50%, and power increased 20%. City Bus System Operation Application of VNT effective solution to the problem of smoky and dynamic badly when accelerating. In its transient process of using VNT make diesel response speed more quickly. And proved Bus Six Cylinder Diesel Engine Electronic Control Matching Application of VNT can substantially improve the overall bus performance, reduction of diesel emissions and satisfy China's largest city bus from the EU II emission standards to Euro III emission standards for the transition period. So it is practical significance.
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