GB850353A - Liquid fuel pumps for internal combustion engines - Google Patents

Abstract

850,353. Fuel injection pumps. C. A. V. Ltd. April 13, 1959 [April 14, 1958]. No. 11734/58. Class 102(1). A fuel-injection pump comprises a rotating distributer and cylinder block which are movable axially of the housing to vary the quantity of fuel injected. In the embodiment shown in Fig. 1, a supply pump 12 actuated from the drive shaft feeds fuel to passage 25 which communicates successively with passages 24 in the rotary distributor 5. The piston 7 actuated by a cam 8 deliver the fuel past a non- return valve 21 and passage 22 to the lines 23 leading to the engine cylinders. An extension 9 of the distribute is splined on to the drive shaft and carries centrifugal weights 11 which move the shaft axially against an adjustable spring loading 31. The inlet passages 24 terminate in oblique grooves 24a and when the distributer is moved in one direction the grooves 24a connect the axial passage 20 with the inlet before the end of the pump delivery stroke and thus reduce the quantity of fuel injected. Alternatively the grooves 24a may be omitted in which case the movement of the distributer throttles the inlet feed to the pump and thus reduces the quantity delivered. The distributer may be moved by hand and the feed pump may be a gear or vane pump. In a modification, Fig. 3, the axial passage 20 extends beyond the passage 22 to a chamber containing a shuttle piston 33. The fuel feed passage 25 has a branch 37 communicating by a groove 36 and passage 35 with side of the shuttle piston 33 opposite the passage 20. The axial position of the distributer 5 determines the pressure acting on the piston 33 when the passages 24, 25 and 22, 23 are out of communication and this pressure moves the shuttle piston to the left until passages 24, 25 are in communication. During the subsequent delivery stroke the shuttle piston 33 is moved to engage an adjustable stop 34 before fuel is delivered, thus if the groove 36 is in full communication with passage 37 the piston 33 moves fully to the left and little if any fuel is discharged on the subsequent delivery stroke. If the groove 36 is out of communication with the passage 37 the piston 33 does not move to the left and a full delivery takes place subsequently.