GB698743A - Improvements in hydraulic revolution speed governor for injection internal combustion engine - Google Patents

Abstract

698,743. Fluid-pressure servomotor-control systems. BOSCH GES., R. Dec. 20, 1950 [Dec. 24, 1949], No. 30984/50. Class 135 A speed governor for an I-C engine comprises a gear-pump 2 driven from the cam shaft of the engine-driven fuel injection pump and supplying liquid, e.g. fuel, under pressure through a passage 5 to a chamber 6a containing a servo piston 7 which actuates the injection pump control rod 14. The piston is coaxial with a control piston 19 the conical end of which co-acts with a bore 18 in the piston 7 to form an annular throttle opening 18a. Pressure liquid passes through the opening 18a into a chamber 6b the outlet 16 of which is throttled by a rod 17, whereby pressure builds up in the chamber and acts on the piston 19 against a spring 21. Thus the piston 7 takes up a position, when the engine is on speed, where the resultant force due to the pressures on opposite sides of the piston equals the force of a spring 8. An increase of speed will cause the pressure in the chamber 6b to increase and push the piston 19 against its spring to increase the opening 18a whereby the resultant force falls and the spring 8 moves the piston 7 and hence the rod 14 to decrease the fuel supply. When the pressure drops to zero, the spring 8 moves both pistons 7, 19 to cut off the fuel supply. If the pressure in chamber 6b rises unduly, piston 19 moves to exhaust the chamber via ports 31 to the inlet of pump 2. The control point of the governor is set by an arm 25 operable between stops and actuating a lever 23 simultaneously to increase the load of spring 21 and enlarge the outlet 16 and vice-versa.