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US 2003/0111548 A1Published application
Injector for a common rail fuel injection system, with shaping of the injection course
AssigneeRobert Bosch GmbH
InventorRainer Buck
Life of this patent
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Abstract
A common rail injector is proposed which offers great freedom in designing the course of the preinjection main injection and of the injection pressure. Moreover, it offers improved security against leaks into the combustion chamber, caused for instance by a leaking nozzle needle valve seat.
Claims21
An injector for a common rail fuel injection system for internal combustion engines, comprising,
- an injection nozzle (7) that has a nozzle needle (31),
- a control chamber (3), subdivided into first, second and third portions (13, 15, 17) by a control plunger (11),
- the first portion (13) and second portion (15) communicating hydraulically via an inlet throttle (19) disposed in the control plunger (11), the second portion (15) hydraulically communicating with a high-pressure connection (1), and the third portion (17) hydraulically communicating with an inlet conduit (5) to the nozzle needle,
- the control plunger (11) having two grooves (23, 25) separated by a slide (27) embodied on the control plunger (11), the slide cooperating with a control edge (47) of the guide bore (9), when the injection nozzle (7) is closed, to effect an extensive hydraulic separation between the high-pressure connection (1) and the inlet conduit (5) to the nozzle needle,
- the stroke of the nozzle needle (31) and the stroke of the control plunger (11) being coupled with one another,
- a hydraulic connection (55) between the high-pressure connection (1), or the second portion (15), and the inlet conduit (5) to the nozzle needle, and,
- a multi-port directional control valve operable to close the hydraulic connection (55).
4 more elements
Dependencies are inferred from the claim text.