Abstract A fuel injection pump comprises a rotor (21) located in a housing (22, 23), a free piston (40) movably mounted in an axial bore of the rotor (21), two pump chambers (41, 42) which is formed by dividing said bore by the free piston, and two solenoid valves (27, 28) for supplying fuel to the two pump chambers, one of the chambers (41) receiving therein the fuel to be injected and the other (42) for effecting control of the injection timing. This injection pump is characterized in that two preparatory chambers (33, 34) are provided downstream of the solenoid valves (27, 28) to keep fuel measured by the solenoid valves during the compression operation of said pump chambers and transfer the fuel to said pump chamber after completion of the compression whereby precise measurement of the fuel can be effected.
,1. A fuel injection pump for an internal combustion engine comprising: a rotor (21) disposed in a housing (22, 23) and rotating according to running of the engine; a pressure chamber formed in said rotor; a first free piston (40) slidably mounted in said pressure chamber; first'and second pump chambers (41, 42) defined by an inner surface of said pressure chamber and said first free piston (40), said first pump chamber (41) provided with an port which is capable of communication with an interior of the engine; and said second pump chamber (42) provided with a discharge port; means for compressing fuel in said second pump chamber (42)'in accordance with rotation of said rotor (21) whereby the fuel in said first chamber (41) is compressed and delivered to said engine through said port; first and second fuel passage means leading to said first and second pump chambers (41, 42), respectively; first and second solenoid valves (28, 29), provided on said first and second passage means (31; 32), for measuring amount of fuel; and first and second preparatory chambers (33, 34) provided downstream of said first and second solenoid valves (28, 29), respectively, said chambers being capable of communication with said first and second solenoid valves and said first and second pump chambers (41, 42) by said first and second fuel passage means so that the measured fuel is kept in said first and second preparatory chambers during the compression of said pump chambers and transferred to said first and second pump chambers, respectively.
Claim 2
Dependent Claim
62 words
The fuel injection pump as defined in claim 1, wherein said first and second preparatory chambers (33, 34) comprises cylinders and second free pistons (35, 36) movably mounted in said cylinders, respectively, and are arranged in said housing such that the axes of said first and second preparatory chambers are disposed in a plane perpendicular to the axis of said rotor (21).
Claim 3
Dependent Claim
108 words
The fuel injection pump as defined in claim 2, further including a feed pump (24) for supplying a fuel to said first and second passage means, wherein said rotor (21) is provided with switching means, and each of said first and second preparatory chambers (33, 34) is divided into two chambers (33, 33'; 34, 34') by said second free pistons (35, 36), each of said two divided chambers being brought into communication with said feed pump alternatively by said switching means (37) so that the pressure of said feed pump (24) applied on one of said chambers delivers the fuel in the other chamber to said pump chamber.
Claim 4
Dependent Claim
24 words
The fuel injection pump as defined in claim 3, wherein said switching (37) means are grooves formed on the periphery of said rotor (21).
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.