GB524160A - New and improved method and means for limiting the maximum revolution speed of injection-type internal combustion engines - Google Patents

Abstract

524,160. Fuel-injection pumps. DIAMLERBENZ AKT.-GES. Jan. 23, 1939, Nos. 2310 and 2312. Convention dates, Jan. 22, 1938 and March 9, 1938. [Class 102 (i)] A device for regulating the fuel-injection pump of an internal-combustion engine, of the kind operating with a relief or overflow at the end of each delivery stroke, comprises a slide valve 19 displaceable in the suction passage 11 of the pump cylinders 14 for variably throttling said passage, displacements of said valve being produced against the action of a spring 31 in dependence upon the fuel pressure in the relief passages 12, 13 (i.e. by the pressure difference between the suction and relief passages), which pressure (or pressure difference) varies with the speed of the engine. The pump cylinders 14 are connected by ports 18 to passage 12 and by ports 17 to tapered annular grooves 29 and ports 30 in the hollow valve 19. The latter is provided at one end with a throttle opening 20, and its movements are limited by adjustable stops 21, 22, whilst the loading of the spring 31 is adjusted by screwing in and out a hollow plug 50. In a modification, the throttle passage 20 is located in the cylindrical wall of the valve 19 and is fitted with an externally-operated needle valve. Each piston 15 may be initially adjusted on a test bench, to compensate for inaccuracies in machining, and to determine the quantity of fuel normally delivered, by providing them with milled flats 37 to engage slotted toothed segments 38 which are held in the desired position by set screws 39. Opposite the ports 17, 18, the pump casing may be closed by plugs 40, 41. The Specification as open to inspection under Sect. 91 states also that the pump casing may be die-cast in grey iron or light metal, and the cylinders and passages formed by means of bushes made of steel or brass which are cast, pressed, or shrunk into position, preferably in the form of solid bodies which are afterwards bored. This subject-matter does not appear in the Specification as accepted.