GB725585A - Improvements in and relating to fuel injection systems in internal combustion engines - Google Patents

Abstract

725,585. Fuel injection systems ; alarms. AKTIESELSKABET BURMEISTER & WAIN'S MASKIN-& SKIBSBYGGERI. March 12, 1953 [June 23, 1952], No. 6896/53. Classes 7 (2) and 7 (3). [Also in Group XXVIII] A fuel-injection system comprises a separate injection pump 1 for each engine cylinder actuated by the pressure in its associated engine cylinder and connected to two or more fuel pressure operated injection valves 19, 20 in the cylinder, at least one of which opens at a pump delivery pressure produced by an engine cylinder pressure lower than the lowest compression pressure at top dead centre obtaining under the most unfavourable operating conditions, e.g. when the engine is rotating slowly as at starting, while the remaining valve or valves open at fuel pressures produced by engine cylinder pressures located between the abovementioned lowest compression pressure and the compression pressure at top dead centre obtaining under normal running conditions. The pump plunger 1 is actuated by a spring- loaded piston 3 subject to engine cylinder pressure through a port 5 and is rotatable by a lever 58 and provided with helical control edges 57, 53 controlling the outlet and release ports 13, 54 respectively. The fuel is fed to the intake port 12 from a tank 9 by a supply pump 8 and the fuel released when the port 54 is opened is delivered back to the tank 9 through a pipe 56. The pump delivery pipe 15 is connected by branches 17, 18 to the injectors 19, 20 which include spring-loaded valves 25, 26 set to open at different pressures, and a third branch 21 from the pipe 15 leads to an overflow device 41 containing a spring-loaded valve 42 which is lifted by an excessive fuel delivery pressure to allow fuel to escape through a pipe 50 to the tank 9 and relieve the pressure in the pipes 17, 18. The valve 42 is preferably arranged to close at a much lower pressure than its opening pressure, e.g. it may open at a fuel pressure produced by an engine cylinder pressure of 52 kg. per square cm. and close at a cylinder pressure of 18 kg. per square cm. The valves 19, 20 however, are arranged with only a small difference between the opening and closing pressure, e.g. valve 20 may open and close at cylinder pressures of 25 and 20 kg. per square cm. respectively and the valve 19 may open and close at 32 and 25 kg. per square cm. A sight glass chamber 66 may be provided in the overflow pipe 50 to indicate faulty operation of the engine.