Common Rail Injector with Injection Rate Control

A Common Rail injector with Injection Rate Control (IRC) has been conceived, designed and tested on a hydraulic injector test bench. The opening of the injector's nozzle needle valve is electro-hydraulically controlled by a double-stop solenoid valve. When the solenoid valve moves only through the first stop, the needle valve opens slowly. When it moves through the first and second stops, the needle valve opens fast. In the first part of the injection event it is therefore possible to switch from a low to a high fuel injection rate, whereas the switch-over point can be selected electronically. The proposed design allows to maintain the flexibility of a conventional common rail injector with or without pilot in-jection and adds the feature of a fully controllable initial shape of the injection rate.