Research On Flow Characteristic Of Motorcycle Electronic Injector

Flow characteristic of electronic control injector will directly affect the dynamic property, efficiency and emission performance of engine. Usually injection pulse width can be on behalf of the quantity of fuel injection, gasoline engine electronic control unit (ECU) calculates fuel injection quantity in accordance with the normal linear characteristics of flow characteristic. Due to the fact that it is generally difficult to accurately calculate the nonlinear section of flow characteristics curve of small injection pulse width of electronic control injector, it is impossible for ECU to accurately control fuel injection quantity, when the small engine such as motorcycle is under a working condition of idle speed or small load and the injection pulse width is in a state of small and medium-sized injection pulse width of flow characteristic, Given the importance of the nature of nonlinear section of the small fuel injection pulse-width segment, appropriate the fitting method should be taken in the experiment of injector.This paper introduces the principle and method software developed by fitting small injection pulse width in the system of nonlinear section of the flow characteristic. Combined with the LabVIEW software programming, the research and development of the software of the host computer system has been carried on, for the rapid and convenient real time control of lower machine, and the operation of the injector. The quantity of fuel injection in the experiment can be obtained by means of combining the use of capacitive liquid level sensor and the next process in the first machine. The result of the experiment from the sensor can be obtained by fitting calculation by the least squares in the upper machine system data. The experimental error test shows this measurement system can accurately and real-time obtain the important parameters of motorcycle electric control fuel injector including invalid injection time, static injection rate, small injection pulse width and the normal flow characteristic of injection pulse width. It will achieve the goal of high efficiency, fast and accurate measurement of flow characteristic of motorcycle electric injector.The experiment data of the flow characteristic under different jet pressure shows: The size of pressure of fuel injector has certain influence on the flow characteristic of small injection pulse width segment; in the normal flow characteristic of pulse width segment, there is positive correlation between the fuel injection quantity and the fuel pressure. Due to the differential pressure for injector with flow characteristic has a great influence, the pressure of fuel should be steady in the course of measuring flow characteristic of motorcycle electric injector. Usually the error of pressure stability ranges from-0.33%to0.33%.The experimental results of fuel injector under different working voltage shows: The greater working voltage of fuel injector is, the smaller the invalid injection time will be; the fuel injector work voltage has little influence on flow characteristic of normal pulse width segment. Due to the differential working voltage of injector has a great influence on invalid injection time. The working voltage should be steady in the course of measuring flow characteristic of motorcycle electric injector. Usually the error of working voltage stability ranges from-0.35%to0.35%.