摘要 |
An advance arrangement for controlling timing of fuel delivery by a fuel pump in an engine comprises an advance piston which is movable in either an advance or a retard direction to advance or retard, respectively, the timing of fuel pump delivery, wherein a surface associated with the advance piston is exposed to fuel pressure within a main advance control chamber. The advance piston has a supply port to allow fuel to flow into the main advance control chamber and a drain port to allow fuel to flow out of the main advance control chamber. A servo piston is movable relative to the advance piston to control opening and closing of the supply port and the drain port. The advance arrangement is characterised by a restricted flow means for restricting the flow of fuel out of the main advance control chamber through the drain port when the advance piston moves in the retard direction beyond a predetermined amount.
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