GB725152A - Improvements in piston pumps for the injection of fuel into internal combustion engines - Google Patents

Abstract

725,152. Fuel-injection pumps. PRECISION MECANIQUE. Jan. 13, 1953 [Jan. 21, 1952], No. 1034/53. Class 102 (1). In a fuel-injection pump, the piston 1 is connected to a cross bar 18 by a coupling 26, of the Oldham type, and the cross bar 18 is rotated by a shaft 16 and carries cams 19 cooperating with cams 21 so that a combined rotary and reciprocating movement is transmitted to the piston. Fuel is drawn through the inlet 5 and delivered past the valve 10 to a passage 11 leading to a circumferential groove 12 in the piston which communicates with an axial groove 13 co-operating with cylinder ports 14 to distribute the fuel to the engine cylinders. The position of the groove 13, ports 14 and the cams 19, 21 causing the reciprocation is chosen so that if the engine should run in the reverse direction, then the timing of the injection is unsuitable for continued running. The same effect is obtained by providing one or more channels 100 in the head 2 of the piston and co-operating with one or more inlet ports. The position of the channels 100 are chosen relatively to the cams 19, 21 so that as shown in Fig. 12, 14, the inlet port is retained in communication with the pumping chamber after it has been closed by the edge 3 of the piston if the engine reverses and thus no fuel is delivered. The cams 19 on the cross bar 18 co-operate with rollers 21 carried in the ring 20 which is adjustable by a worm 27 to vary the time of injection. The cross bar 18 may act as a piston to draw fuel through valve 30 and deliver it through valve 31 to the port 5. The valve 10 has an axial groove 33 for a portion of its length and lower edge 35 of the groove co-operates with an inclined edge 34 of the casing so that the valve can be rotated to vary the amount of fuel delivered; the valve also reduces the delivery as the speed increases.