| 摘要 |
The invention relates to a device for adjusting the supply onset of a fuel injection pump for internal combustion engines, by means of which the injection onset is adjustable in several stages. A roller tappet provided with a hydraulic tappet chamber for prestroke variation is fixable in defined positions via a control fluid. To this end the roller tappet has at least one first control bore and one second control bore communicating with the tappet chamber and can be made to communicate with openings in a housing bore that receives the tappet. The control bores are provided at differing heights, and/or with differing diameters or are offset from one another, at least one of the these control bores is closable by means of a control piston of the hydraulic tappet, and the control bores are openable as a function of an engine parameter via hydraulic lines.
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