GB628016A - Improvements in or relating to fuel injection pumps for internal combustion engines - Google Patents

Abstract

628,016. Fuel-injection pumps. EVANS, A. F., and HOPKINS, S. March 10, 1947, No. 6682. [Class 102(i)] A fuel-injection pump of the type having a plunger 13 adapted to reciprocate within a fixed sleeve 23 which has a spill port 34 spaced rearwardly of a suction port 24, the plunger being provided with an axial bore 25 communicating with a diametral hole 26 which is unmasked by the helical edge of the spill port to terminate injection and the plunger being rotatable to vary the pump delivery, a thin ferrule 35 the inner edge of which joins the helical edge 33 of the spill port is pressed into the rear end of the sleeve. Fuel is supplied under a pressure of about 10 lbs. per sq. inch through an inlet 11 and is delivered through a delivery valve 27 to an injection nozzle 17, the excess fuel being returned to supply through an outlet 12. Two spill ports and two suction ports are zonally provided diametrically opposite to each other respectively to prevent lateral pressure on the sleeve. The plunger is rotated by a rack 39 through a pinion disc 41 and sleeve 44 spliced to the plunger, the disc and sleeve being rotatably adjustable relative to each other by a fine worm thread so as to provide independent adjustment when a number of pumps are connected by a common rack. The plunger may be actuated mechanically, e.g. by a cam acting on a tappet head 22 or in another embodiment by air compressed in an engine cylinder acting on a motor piston coaxial with the plunger and which may be admitted through a tappet operated air timing valve, the return stroke in each case being effected by a spring such as 20. Specification 626,994 is referred to.