Abstract: A temperature compensated actuator device comprises a piezoelectric stack having first and second ends along a central axis and having a first thermal expansion coefficient; and a compensator arranged on one end of the piezoelectric stack. The compensator comprises a first member in form of a cylinder; a second member in form of a piston plate wherein the first member and the second member are arranged movably along the axis with respect to each other and define a hollow space between them; and a compensation member having a thermal expansion coefficient higher than the first thermal expansion coefficient for filling the hollow space.

Abstract: An oil activated fuel injector which provides a pilot quantity of fuel prior to the main fuel injection event. The oil activated fuel injector includes a throttle which provides fluid communication between the high pressure chamber and a fuel bore which leads to the nozzle of the oil activated fuel injector. The pilot quantity of fuel flows through the throttle and into the fuel bore during a pre stroke of the plunger. The oil activated fuel injector reduces engine emissions and noise, and eliminates the need for additional working fluid to be provided therein in order to provide a pilot quantity of fuel.

Abstract: An oil activated fuel injector control valve which substantially eliminates captured air within working fluid of the fuel injector. This eliminates shot by shot variations in the fuel injector as well as increasing the efficiency of the fuel injector. The fuel injector includes a control valve body which has vent holes which prevent air from mixing with the working fluid. In this manner, the working fluid does not have to compress and/or dissolve the air in the working ports prior to acting on the piston and plunger mechanism in an intensifier body of the fuel injector.

Abstract: An oil activated fuel injector which includes a control valve having a groove which provides a fluid path between a bore and a cross bore of the valve body. The fluid path leads to ambient such that a pressure within a pressure chamber is less than that of the rail pressure. This equalized pressure allows the spool within the valve body to move to a first position thus forming a fluid path between an inlet port and the working port leading to the intensifier chamber. When the fluid path is blocked, via movement of the groove out of alignment with the cross bar, the pressure within the pressure chamber increases thereby forcing the spool to move towards a second position. In the second position, a space is formed between the spool and the body of the injector to provide venting of the working fluid from the intensifier chamber to ambient.