GB861753A - Improvements in fuel injection devices - Google Patents

Abstract

861,753. Fuel injection pumps. BESSIERE, P. E. May 21, 1957 [May 24, 1956], No. 16129/57. Class 102(1). A fuel injection pump comprises a plunger 1 reciprocating in a cylinder 2 having an inlet port 3 and outlet passage 4 leading to an injector, the piston being driven in accordance with the engine speed such that its speed increases during its compression stroke. A piston member 8 is provided with an axial passage 5 opening into a chamber 6 and passageway 7. The outlet of the passage 5 may be adjustable. In operation after the piston 1 has closed the inlet port 3 fuel leaks through the passage 5 until the pressure in the cylinder 2 increases to move the piston member 8 against a spring force 9 to close the passage 5 from the chamber 6. The pressure in the cylinder 2 then rises quickly until it reaches a value to open a non-return valve in the outlet passage 4 and flow to the injector. As the speed of the engine increases so will the passage 5 be closed sooner thus providing an advance in timing with increased engine speed. In a modified form the lower end of the piston member 8 may close the outlet passage 4 in its lower most position. In a further modifica tion the spring 9 may be replaced by a magnetic locking device as described in Specification 841,202. In another modification the piston 8 is replaced by a piston member having a tapered lowered end such that once this member has started to move it offers an increased area to fuel pressure acting on it. An adjustable abutment 13 is provided to limit the movement of the piston 8 and by suitable adjustment the piston 8 may be utilised to decrease the volume of fuel injected in each cycle by being displaced. sufficiently to provide a space to be filled by the fuel from the cylinder 2. The leak device may be arranged in the outlet passage 4 or may be provided in a space filled with liquid but separated from the cylinder 2 by a free piston or diaphragm.