Method for detecting fuel injection performance of fuel injection valve.

摘要

In a method for detecting the fuel injection performance of a fuel injection valve in which a nozzle needle (7) biased by a spring member (9) for establishing valve opening pressure is lifted off from the valve seat (3a) when pressurized fuel is supplied thereto, electric data corresponding to the wave form of the shock wave produced in the spring member (9) when fuel is injected is detected at one end of the spring member (9), and time-course change in the pressure of injected fuel acting on the nozzle needle during the fuel injection operation is determined on the basis of the time-course change in magnitude of the shock wave returning from the nozzle needle side end in the spring member by reflection, whereby various fuel injection factors can be calculated form the determined pressure of injected fuel acting on the nozzle needle (7) during the fuel injection operation.