A Study On Influence Of Fuel Injection Characteristics On Economic Performance And Exhaust Emission Of Diesel Engine

Parameters of injection control system have important influence on fuel economyand emission performance of electric control CR diesel engine. In this paper, theinfluence of injection characteristics on economic performance and exhaust emissionof CR diesel engine was studied by measuring the diesel engine fuel consumption andemissions on the setting condition with different parameters of injectioncharacteristics. With the main objective of reducing NO_xemissions and no remarkableworse of fuel consumption and PM emissions, the parameters of injectioncharacteristics were optimized on the original basis. The main contents and results ofthe research are as follows:(1)According to the diesel engine combustion process and its relative impactingfactors, the author analyzed the ideal injection rule of both low fuel consumption andlow emission. Then combined with control characteristics of CR fuel injection system,the ideal pilot injection strategy and parameters of injection (pilot injection quantity,time interval between main injection and pilot injection, main injection timing, the railpressure, and total injection quantity) were analyzed for the influence of injectioncharacteristics on economic performance and exhaust emission of CR diesel engine.(2)Based on the existing engine condition control and data measurement system,the test system which can measure the diesel engine fuel consumption, NO_xand PMemissions with different parameters of injection characteristics was designed byadding the fuel injection control parameter modification subsystem and a centralcontrol system. And the communication module of the central control system wasdeveloped in LabVIEW.(3)Based on the experiment, the influence of the injection control parameters onspecific fuel consumption, soot emission and NO_xemission of NAVECO CR dieselengine was analyzed. The research shows that: fuel consumption could be lowed byhigher rail pressure and larger main injection timing; NO_xemission could be lowed bylower rail pressure, smaller main injection timing and pilot injection quantity; andsmoke emission could be lowed by smaller main injection timing and pilot injectionquantity, higher rail pressure and longer time interval between main injection andpilot injection. In the conclusion, after optimized the parameters on injection systemof this diesel engine based on the original foundation, NO_xemission and specific fuelconsumption of the diesel engine had been improved. However, smoke emissionhadn't been improved as expected.