GB885297A - Improvements in self-regulating reciprocating piston pumps, in particular for the injection of fuel into internal combustion engines - Google Patents

Abstract

885,297. Fuel injection pumps. BESSIERE, P. E. July 3, 1958 [July 8, 1957 ; Jan. 13, 1958], No. 21372/58. Class 102(1). [Also in Group XXIX] A fuel injection pump comprises a main piston 2 driven from the engine which on its discharge stroke lifts a spring loaded valve 22 to close conduit 11 and allow the fuel to be delivered past non-return valve 25 into chamber 6a thus actuating an auxiliary spring loaded piston 5 which delivers fuel in a chamber 6b past outlet valve 10 to the engine cylinders, a by-pass passage 8 determining the end of the stroke of piston 5. On the suction stroke of the main piston 2 the valve 22 returns opening conduit 11 and the auxiliary piston 5 moves under the action of spring 7 and transfers the fuel in chamber 6a to chamber 6b by way of conduit 11. The conduit 11 contains a throttle valve 12 which is adjustable in accordance with the engine speed so that at a predetermined engine speed the throttle passage is such that the piston 5 does not complete its downward stroke before the piston 2 starts its discharge stroke and hence the quantity of fuel transferred from chamber 6a to 6b and subsequently discharged is reduced until at a certain engine speed the conduit 11 is completly closed by the throttle valve 12 when no fuel is discharged from the pump. The axial adjustment of the throttle valve 12 may be made by a speed governor or as shown by a gear pump, driven by the engine, which delivers liquid to the bottom of the valve 12. The return line of this gear pump being controlled by an adjustable throttle 19. The throttle 19 may be in the form of a valve also loaded by the gear pump 17 or by a separate gear pump driven by the engine (see Group XXIX). The Specification also describes various shapes of passages for the throttle portion 14. A single throttle valve may also be used for several pumps each delivering to a separate engine cylinder. In a further modification a single valve member similar to 22 may be incorporated which also closes the conduit 11 between the throttle and the chamber 6b to prevent high pressure fuel acting from chambers 6a and 6b acting on the throttle during the discharge stroke of piston 2 and hence piston 5. Specification 861,754 is referred to.