GB343378A - Improvements in and relating to fuel injectior devices for internal combustion engines - Google Patents

Abstract

343,378. Fuel pumps for internalcombustion engines. LARSEN, S. A., 2, Brigadegaarden, Copenhagen. April 9, 1930, No. 11256. [Class 102 (i).] A pressure accumulator charged by a fuel pump commences to operate when the pressure in the system is reduced and isolates the charge of fuel to be injected into the engine. A fuel pump 1 has an over. flow piston valve 6 provided with a face 7 limited by an oblique edge 8 and a level cut-off edge 9, pivotally mounted on a cam-actuated crossbeam 15 carrying a guide rod 17 connected through a regulating-arm 19 to the engine governor. The valve controls a byepass 12 which communicates with the suction chamber 14 of the pump to stop the delivery of fuel to the housing 4 through the pipe 3. The pump ensures that fuel injection always takes place at the same time, independent of the amount of the fuel injected. The pressure accumulator comprises a spring-loaded piston 21 which, at its lower end, encloses the enlarged head 26 of another piston 27 of smaller diameter by a ring 37 screwed into the piston 21, and flat seating surfaces 25, 28 are formed on the bottom of the piston 21 and the head 26. During the delivery stroke of the pump, fuel passes the groove 30, filling the chamber 32 and raising the piston 21 against the compression of the spring thereby raising the piston 27. As the piston 27 travels upward, communication between the groove 30 and the channel 32 is cut off, fuel then flowing to 32 through chambers 34, 24 and the bore 29. When the byepass operates, the spring forces the seatings 25, 28 into contact, isolates the fuel in the cavity 32 and the passage 33, and injects it through the spring-loaded fuel valve 39 and nozzle 44 into the combustion chamber until the groove 30 communicates with the chamber 32 again, when injection ceases. In a modification, the accumulator piston 21 may be loaded by a pressure medium instead of by a spring. In another modification, Fig. 3, two pumps 1 deliver fuel to pressure accumulators 4, in which the pistons 21 and the fuel valves 56 are loaded by compressed air supplied by a compresser 53, the valves 56 being separated from the accumulators. A pressure-regulating device, comprising a spring- loaded valve 59 controlling the communication of the pressure pipe 54 with a release passage 48, is adjusted by a lever 61 and a handle 62 identical with the speed-regulating handle for the fuel supply to the engine. In a further modification, the accumulator 4 is connected with the pressure piping, while the fuel valve is loaded by a spring &c. The compressed air may be replaced by liquid under pressure.