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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.

High injection pressures are a must in today's DI diesel engine fuel injection systems. The Common Rail injection system (CR), introduced in mass production about 2 1/2 years ago, will follow the trend valid for other fuel injection equipment (FIE), which calls for ever higher pressures. A CR injector design suitable for injection pressures of 2000 bar or more is presented in this paper. According to this design, injector prototypes suitable for passenger car and heavy duty truck applications have been realized. Important aspects for CR injectors operating at these high pressures are: minimizing the hydraulic force acting on the solenoid control valve; minimizing the injector's static and dynamic leakage; stiffness of the injector and needle control components; These aspects are analyzed and the resulting injector performance measurements are presented here.