Patent GB-1107083-A (GB)
Title: Improvements in or relating to methods of and apparatus for fuel injection
IPC: F02M61/12
Filed: 1965-05-26
Abstract: 1,107, 083. Fuel injection systems; reciprocating pumps; hydraulic accumulators. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. May 26, 1965 [May 29, 1964], No. 22361/65. Headings F1A, F1B and F1P. In a fuel injection system fuel from tank 1, Fig. 1 is supplied by pump 5 to a buffer vessel 7 which is kept at a nominal pressure by a gas and which is variable in size substantially without resistance, the nominal pressure being adjusted by a pressure control device 13 so that intermittent fuel delivery to an electronically controlled electromagnetic valve 9 causes pressure variations of less than 1%, the valve 9 having short and equal closing and opening periods. A pulse source 17 controlled as a function of the position of throttle valve 19 controls the opening periods of valve 9. Pump 5, Fig. 2, is driven from the spindle 21 of distributer 23 and has one or more cams 25, Fig. 2 moving plunger 27. Steel bushes 35, 37 bonded to diaphragm 33 are secured respectively to casing 28 and plunger 27. The diaphragm 33 may have a thin layer of fuel-impervious material. Spring flap valves 43 are arranged in the inlet and outlet ducts. Buffer vessel 7, Fig. 3 which may be integral with pump 5 and pressure control device 13 comprises a closed vessel 53 containing a slack diaphragm 54 filled with fuel. Diaphragm 54 is either a length of tube secured at each end to vessel 53 or is a bag having a ring for securing to wall 57. Space 58 is filled with a gas, e.g. air, or the space 59 is filled with gas and space 58 filled with fuel. In other embodiments vessel 53 is a hollow sphere separated into two chambers by a diaphragm or may be an oblate spheroid containing a gas cushion. Diaphragm 55 may be double walled. Magnetically-operated inlet and outlet valves 65 having valve elements 69 seating on elastic seatings 71, are opened when the engine ignition is switched on and closed when the ignition is switched off to maintain pressure in the buffer vessel. Valves 65 may be replaced by a single larger valve or omitted. The pressure relief valve 15 comprises a movable body 87 carrying a closure element 88 via a spring- loaded telescopic connection 92. Element 88 is lifted off valve seat 89 by the pressure in space 81 pushing diaphragm 90 against springs 91. In the atmospheric pressure and temperature control device 13, Fig. 6, fuel from relief valve 15 enters bellows 96 and acts against the atmospheric pressure tending to compress bellows 101. At a predetermined pressure needle 97 is lifted to allow fuel flow to tank 1. Back pressure of fuel acts through line 103, Fig. 1, on diaphragm 90. In valve 9, Fig. 7 a spring-loaded valve needle 109 secured to armature 125 is lifted by electromagnet 119. A perforated diaphragm 112, secured to valve needle 109, is engaged with axial and radial clearance in groove 115. During valve needle movements fuel in groove 115 stabilizes the outer edge of the diaphragm whilst the centre of the diaphragm flexes. The upward movement of armature 125 is braked by fuel escaping from recess 135 and subsequent flexing of discs 133, 135. In a modification the pressure buffer vessel may be divided into separate vessels with throttle areas in the interconnecting channels.