GB1505301A - Fuel injection pumps - Google Patents

Abstract

1505301 Fuel injection pumps ROBERT BOSCH GmbH 20 May 1975 [12 Oct 1974] 21404/75 Heading F1A In a fuel injection pump having a piston 8 simultaneously reciprocable and rotatable within a cylinder 9 to pump and distribute fuel from a working chamber 11, the commencement of fuel delivery and thus the quantity delivered is determined by the closure of a spill passage 26 by a sleeve valve 25 controlled by a centrifugal governor 44. The spill passage 26 is in permanent communication with an annular groove 60 in the cylinder 9 and, during normal operation, delivery is terminated when a relief passage 61, 62 in the piston 8 communicates with the annular groove 60. During starting excess fuel is delivered, since the position of the valve sleeve 25 is arranged to close the relief passage 61, 62 before it is opened by the groove 60. A lever system 29 is disposed between the valve sleeve 25 and the output sleeve 47 of the governor 44. The lever system 29 comprises an intermediate lever 35 carrying a spindle 40 on which a regulating lever 33 and a starting lever 34 are pivotable, the latter carrying a spherical head 31 engaged in a recess 32 in the valve sleeve 25. The position of the intermediate lever 35 is angularly adjustable about fixed journals 41 to determine the basic setting of the valve sleeve 25 by means of a set-screw 56 and a spring 57. At start-up the governor sleeve 47 causes pivoting of the starting lever 34 alone, against the action of a weak spring 42, but as the speed increases a stop pin 43 on the starting lever 34 prevents further compression of the spring 42, whereafter both levers pivot together against the action of an adjustable tension spring 37. Reciprocation of the piston 8 is effected by a face cam 3 rotatable with the piston and co-operable with rollers 5 on a carrier 65. A piston 66 loaded by series-connected springs 67, 71 and pressurized by the delivery of a feed pump 69 adjusts the angular position of the carrier 65 for changing the timing of injection. The working chamber 11 is filled with fuel during each suction stroke from a suction chamber 22, through a passage 23 and grooves 24 in the piston. Fuel is delivered in turn to outlet 20 via a delivery valve 12, a chamber 13, a passage 14 and grooves 17, 18.