Patent GB-403981-A (GB)
Title: Improvements in fuel-injector pump timing devices for internal combustion engines
IPC: F02M41/08
Filed: 1932-06-28
Abstract: 403,981. Fuel-injection pumps. RETEL, J. M. R., 130, Rue Perronet, Neuilly-sur-Seine, France. June 28, 1932, No. 18257. [A Specification was laid open to inspection under Sect. 91 of the Acts, June 30, 1932.] [Class 102 (i).] A timing device for fuelinjection pumps comprises a slide valve which controls the passage, to the injector, of fuel delivered by the pump into a reservoir, the slide valve being displaceable by the pressure in the reservoir so as to vary the injection angle or relative time of opening of the slide valve while controlling in the contrary sense the means for regulating the quantity of fuel delivered by the pump into the reservoir. A rotary pump 2, centrally disposed in a cylindrical outer casing ejects fuel, received from a channel 7, through an orifice 6 into the casing from which the fuel penetrates to a chamber c containing a piston 12. The piston 12 constitutes also a slide valve and a number of these with their associated parts are arranged around the axis of the casing and actuated by a single cam 23. A distributer 13 masks an orifice 9 in the piston 12 unless it is opposite symmetrical triangular slots therein, and an axial channel 10 in the piston 12 leads from the orifice to a pump chamber 11. On the upward movement of the piston, the orifice 9 being covered, fuel in the chamber 11 is forced past a spring loaded valve 14 and through a passage 15 into a pressure reservoir 16 and, when a tapered groove 19 in the piston connects the orifices 18, 20 of channels 17, 21, fuel is discharged.into a pipe 22 leading to the injector. In a modification, the passages beneath the valve 14 in the stem thereof open directly on to the guide sleeve therefor and the reservoir supplies the fuel injector before the pump chamber 11 is put into communication with it. A slidable but not rotatable spring-pressed plunger 30 in the reservoir 16 is formed at its lower end with helical projections 30a which engage grooves in a pinion 29 to rotate the pinion when the plunger is axially displaced. The pinion 29 meshes with a pinion 27a feathered on the rod 25 of the piston 12 to rotate the piston and adjust simultaneously the orifice 9 angularly in relation to the distributer 13 and the width of the groove 19 opposite the orifices 18, 20, according to the pressure in the reservoir 16, a smaller masking. period of the orifice 9 coinciding with a greater width of the groove 19. The plunger 30 may be controlled by a series of springs coming into action successively in order that the injection angle (a) may vary with the injection pressure (H) according to the equation a= KHn where K is a constant and n lies between 1 and 2 and is preferably 1.5. The distributor 13 may be adjusted through pinions 37, 38 the latter being on a manually operable rod. At starting, the orifice 9 is opposite the narrow portions of the slots in the distributer 13 and the pump discharges mainly into the reservoir to build up pressure therein. This pressure, through the pinion 30a, rotates the piston 12 bringing the orifice 9 towards the narrower masking portion.