Patent GB-839935-A (GB)
Title: Improved automatic means for adjusting the commencement of injection in reversible fuel-injection internal combustion engines
IPC: F02D1/18
Filed: 1958-04-17
Abstract: 839,935. Fluid-pressure servomotor-control systems. DAIMLER-BENZ A.G. April 17, 1958 [April 17, 1957], No. 12209/58. Class 135. Automatic means for adjusting the commencement of ignition in reversible fuel injection internal combustion engines, wherein hydraulic pressure acting on a piston is controlled by a slide valve in dependence upon engine speed by means of a centrifugal governor and wherein the piston axially displaces a shaft which by means of helically arranged splines effects in the drive of a reversible fuel injection pump a relative angular adjustment which alters the timing of injection, is characterized in that a governor is provided for clockwise running and a second governor for counter-clockwise running. A helically-splined timing shaft 51 has an axial extension in the form of a hollow shaft 9 carrying a piston 6. The shaft 9 is arranged to be axially displaceable in a hollow shaft 2 formed with a cylinder 5 to accommodate the piston 6. The shaft 2 is driven at half crank-shaft speed by a gear 49. Within the hollow shaft slide valves 10 and 11 are located and are separated by a slider 12. The slide valves 10 and 11 have annular grooves 13 and 14 respectively and a respective axial bore 15, 16. By means of pins 17 and 18 the slide valves are connected to abutments 23 and 24 slidably arranged on the shaft 2. These abutments are spring-loaded into conwith the support arms 29 and 31 of centrifugal weights 30 and 32, pivoted to the ends of the cylinder 5. A gear-type oil pump 33 has a common feed-pipe 38 and two outlets 41 and 42 the outlet 41 delivering pressure fluid when the pump bottom gear is rotating clockwise and the outlet 42 for anti-clockwise rotation. During rotation of the shaft 51 in the direction of arrow 50 high pressure fluid is delivered from the pump port 41 and passes into the chamber 45 within the hollow shaft 9. From chamber 45 the high-pressure fluid passes through the bore 15 of the slide valve 10 and forces the slider 12 in the direction of arrow 56, the slider 12 in turn forcing the distributing slide valve 11 in the same direction, so that the abutment 24 is moved out of contact with the centrifugal weights 32. With the slider 12 and slide valve 11 in this position the lefthand side of piston 6 is in communication with the inlet pressure to the pump 33 via piston passage 58 and annular groove 57, bore 16 in slide valve 11, chamber 47, port 42 and pump passage 38. This pressure forms a fluid loading for the piston. With increase in rotational speed of the shaft 51 the weights 30 start to move outwardly causing the slide valve 10 to start moving to the left, thereby uncovering the annular groove 59 and permitting high pressure fluid via piston passage 60 to pass to the right-hand side of piston 6. This pressure causes the piston to move to the left until the annular groove 59 is again blanked-off by the slide valve 10. Movement of the piston causes axial movement of the splined timing shaft 51 and consequent adjustment of the injection timing of the fuel injection pump. When the engine is operating in the reverse direction pump 33 delivers pressure fluid from port 42 instead of port 41 and slide valve 10 is forced out of contact with the centrifugal weights 30. The piston 6 is then controlled by the slide valve 11 in dependence upon the position of the centrifugal weights. 32 and the piston moves in the opposite direction on an increase in speed: Axial movement of the piston 6 thus adjusts the fuel pump injection timing for the engine in its reverse operating direction.