GB907577A - Improvements in or relating to low-pressure fuel injection devices for internal combustion engines - Google Patents

Abstract

907,577. Spray carburetters. REGIE NATIONALE DES USINES RENAULT. Dec. 14, 1959 [Dec. 16, 1958], No. 42437/59. Class 7(3) A low pressure fuel injection device comprises a casing 24 adapted to be mounted on the induction tube 31 of an internal combustion engine, a distributer block 1, having a slide face 5, fixedly mounted in the casing 24, a secondary air duct 3 and a duct 2 for pressurized fuel both extending through a wall of the casing and adjacently opening in the face 5, a slide valve 6 engaging the face 5 and having a chamber 7 for receiving from the ducts 2, 3, and mixing therein fuel and secondary air with flow of fuel being controlled, during operation, by the valve 6, the chamber 7 terminating in an outlet orifice 10 projecting through an opening 36 in the tube 31 downstream of the butterfly 25, whereby an air-fuel mixture can, during operation, be discharged through the orifice 10 into the tube 31, and slide valve positioning means, including pressure responsive means for adjusting the effective discharge cross-section of the fuel passage. The valve 6 has grooves 11, 12 formed in its upper and lower faces respectively which engage blades 13, 14, the upper blade 13 being urged by a spring blade 15 bearing on a knife-edge 16 and prevented from slipping by a groove 18; the arrangement is such that the spring blade 15 bears on screws 17, 22 in turn as the flexion of the blade 15 increases. The lower blade 14 is urged by a lever 20 pivoted on a blade 21. A hole 40 having a conical inner end 41 is formed in the lever 20, the end 41 receiving the spherical tip of a rod 42 rigid with a diaphragm 43 of a vacuum responsive capsule 44. On the atmospheric side of the diaphragm a spring 45 provides a pre-stress transmitted to the spring blade 15 through the lever 20. Thus the diaphragm 43 by means of rod 42 and lever 20 actuates the valve 6 and meters the fuel according to the pressure in the tube 31 which is in communication with the righthand side of the diaphragm 43 through apertures 36, 37. The fuel is also metered according to the engine speed and thus fuel pressure (as the fuel pump is driven by the engine), by means of plate 65 at the end of bellows 64 bearing on lever 20. Registering with a notch 46 formed in the lever 20 but not contacting under normal conditions is the spherical tip of a rod 47 rigid with the diaphragm 48 of a vacuum capsule 49. Exerting a constant thrust on the diaphragm 48 is a spring 50. The opposite side of the diaphragm has an abutment 51 defining the clearance in the notch 46 of rod 47, and is in communication with the tube 31 through pipe 52, circular recess 53, passage 54, leakage hole 55 and an oblique passage 56. The recess 53 is connected to the atmosphere through a hole 57 when a valve 58 opens due to the drop of pressure on the sudden closing of the accelerator valve. The atmospheric pressure acting on the diaphragm 48 forces the rod 47 against lever 20 which in turn moves the slide so as to shut off the fuel. The spring 59 after a time will close the valve 58 allowing fuel to enter the tube 31 and the engine to idle. An easy start device comprises a valve 68 and a shank 69 sliding in member 67. The valve is normally seated by a spring 70 engaging a washer 71 screwed on the shank, but on starting the valve is opened allowing air to enter the tube 31 from port 81 and also the valve moves the lever 20 so as to allow more fuel to enter the tube 31. A chamber in which water from the cooling system flows surrounds the tube 31 in the region of the orifice 4. A hole 38 recovers in the pipe 31 any fuel leaks. In a modification the capsule 44 may be replaced by a case, screwed into the frame 24, containing a metal bellows welded in a fluid tight manner on a pair of plates and containing a mass of reference air. One plate is secured on one wall of the case and the other is rigid with the rod 42. This corrects the fuel output for temperature and pressure. The chamber 10 may be of frusto-conical, oblique frusto-conical or non-conical shape. Specifications 866,414 and 907,576 are referred to.