Crt Common Rail Technologies, Ag

Markus Tappolet

Marco A Ganser

Andreas Carelli

Roland Kolb

Severin Kern

A fuel injection valve for an internal combustion engine which includes an axially moveable needle-like injection valve membermounted in a tubular housing. A control elementwith a control passageis mounted in the upper end portion of the housing, and a valve elementis mounted for movement below the control element. A control chamberis formed below the valve element, and a control pistonwhich is formed at the upper end of the valve memberbounds the lower side of the control chamber. A throttle passagein the valve element is connected via a throttle constriction between the control passagein the control elementand the control chamber. A throttle inlet, which is formed in the valve elementor in a sleevewhich laterally bounds the control chamber, is connected between a high pressure chamberin the housing and the control chamberwithout passage through an intermediate throttle point. The pressure in the control chamberis thus always higher than the pressure in the control passage

Fuel injection valve for internal combustion engines

The control space of the fuel injection valve is delimited, on the one hand, by the piston of the injection-valve member, on the other hand by the slide-valve body and circumferentially by the sleeve. Both the double-acting piston and the slide-valve body are guided in a narrow sliding fit on the sleeve. The throttle passage runs through the slide-valve body and is flow-connected permanently to the control passage in the control body. The throttle inlet leads from the high-pressure space into the control passage. The latter, on the side facing away from the slide-valve body, can, via a pilot valve, be connected to a low-pressure space and be separated again from the latter. The connection of the control passage to the low-pressure space leads to a pressure drop in the control space, with the result being that the injection-valve member moves in the direction of the slide-valve body and releases the injection nozzles. After the control passage has been separated from the low-pressure space, as a result of the pressure difference in the control space and on that side of the slide-valve body which faces away from the latter, the slide-valve body, together with the injection valve, is moved in a direction away from the control body, thus leading to a rapid closing of the injection nozzles. Under the force of the spring element, the slide valve body then again sealingly engages the control body.

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Schaffhausen, Switzerland

Markus Tappolet