Advance variator for a fuel injection pump
AssigneeSpica S.p.A.
InventorManuel Roca Nierga
Life of this patent
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Abstract
The invention relates to an improvement in internal combustion engine injection pump, according to which the injection timing is modified by moving the timing element (9) by means of a hydraulic actuator (41) fed with fuel which varies in pressure with the pump speed and which urges the actuator piston (42) against elastic means which react within an axially mobile rotating cylinder (47), of which the axial position is determined by contact between two cam surfaces (52,56) in series, and of which the rotation is a function of the position of the pump throughput control members.
Claims23
A fuel injection pump for an internal combustion engine comprising a pump casing (1), means (6, 13-15, 23-35, etc.) for effecting and controlling the fuel throughput of said fuel injection pump, means (9) relatively arcuately adjustable in said pump casing (1) for varying the injection timing of said fuel injection pump, hydraulic actuator means (41) for arcuately adjusting said injection timing varying means (9), said hydraulic actuator means (41) includes a reciprocal piston (42) having first and second opposite end portions opposingly biased by fuel pressure and biasing means (44), respectively;
- means (45) operatively coupled between said injection timing varying means (9) and said reciprocal piston (42) for arcuately adjusting said injection timing varying means (9) in response to movement of said reciprocal piston (42), a housing (47) within and movable relative to said pump casing (1) housing said reciprocal piston (42), said housing (47) having opposite first and second end portions, said housing second end portion being exposed to fuel pressure in said pump casing (1), a double cam element (53) having first and second cam surfaces (56 and 52, respectively), said double cam element (53) being positioned with said second cam surface (52) adjacent said housing second end portion whereby said housing second end portion is urged into operative relationship with said second cam surface (52) under the resultant pressure of the fuel pressure acting upon said reciprocal piston (42) and said housing second end portion;
- means (49, 50) for connecting said housing (47) to said fuel throughput effecting and controlling means (6, 13-15, 23-35, etc.) whereby selective movement of said fuel throughput effecting and controlling means (6, 13-15, 23-35, etc.) effects rotary movement of said housing (47) and the position of its operative relationship with said second cam surface (52), and means (57, 60, 64) operative through said first cam surface (56) for shifting said double cam element (53) relative to said housing second end portion thereby shifting said housing (47), said piston (42) and said injection timing varying means (9) through said coupling means (45) to effect a variation in the timing of the commencement of injection pump fuel delivery.
Dependencies are inferred from the claim text.