GB1254454A - Fuel injection apparatus - Google Patents

Abstract

1,254,454. Fuel injection pumps; regulating I. C. engines. V. D. ROOSA. Nov. 20, 1968 [Nov. 20, 1967], No.52388/68. Headings F1A and F1B. Fuel injection apparatus for limiting the rate of fuel supplied to an I. C. engine to that which it can properly combust at any particular engine speed, comprises a fuel injection pump 26, a speed governed metering valve 19 controlling an orifice 15 in the inlet duct 10, 13, 17, 18, 152 to the pump, and a second valve 20, normally open, but movable to a position limiting flow into the pump only when the metering valve 19 is in the fully open position for the particular engine speed required. Fuel enters the apparatus through a port 2 and is drawn through a passage 7 by a feedpump 8 which delivers to the inlet duct 10.... 152 containing the orifice 15. The size of the orifice 15 is determined by the axial position of the valve 19, urged to the right by the action of centrifugal flyweights 30 driven by the engine. Rightward movement of the valve 19 is resisted by a spring 40 and a substantially constant low-pressure established in a chamber 92. To alter the bias of the spring 40 in accordance with the desired speed of the engine, the spring reacts against a movable abutment 42 acted upon by the pressure of fuel in a chamber 50. The chamber 50 receives fuel from the inlet duct at 18, the fuel passing a port 62 controlled by the metering valve 19 and passages 64, 66, 70. A needle valve 48 positioned by a throttle rod 44 controls an axial spill port 46 in the abutment 42 and thereby both the axial position of the abutment and the pressure in the chamber 50. The pressure obtaining in the chamber 50 is directly proportional to the engine speed and is applied through a passage 98 to a cylinder 100. Thus a piston 102 in the cylinder 100 is subject to a force directly proportional to the engine speed. The piston 102 acts through a lever 108 loaded by an adjustable leaf-spring 108a, Fig. 3 (not shown), to cause opening of a needle valve 114, 5 when the engine speed increases. When the flow through the needle valve 114, 5 reaches the maximum desired level for the specific operating speed of the engine, the so increased pressure differential across the valve causes the downward movement of a diaphragm 128. This results in a plunger 130 restricting an orifice 143 through which feed pressure supplied to a chamber 136 escapes to an inlet chamber 6. Thus pressure builds up in the chamber 136 and deflects a power diaphragm 144 to cause pivoting of a lever 96 and consequential movement of the second valve 20 to a position in which it limits the flow from the duct 152 into the pump 26. In a modification, Fig. 4 (not shown) the operation of the valve 20 is compensated for changes in manifold pressure and temperature.