GB889607A - Improvements in or relating to fuel injection control systems for internal combustion engines - Google Patents

Abstract

889,607. Fuel injection systems. LEXING- TON PRODUCTS Ltd. Feb. 14, 1961 [Feb. 22, 1960], No. 6206/60. Class 7(3). In an arrangement for injecting controlled quantities of fuelinto an air manifold 2 of an internal combustion engine a pump 5 is arranged to inject fuel into the air manifold via at least one nozzle 1 arranged in the wall thereof and the output of the pump is controlled in accordance with the load requirements of the engine by first means 7 responsive to engine speed and by second means responsive to a combination of engine speed and pressures obtaining in the manifold in accordance with the part load requirements of the engine both means being interdependent and so arranged that when the engine is operating at part load the pump output is controlled by the first and second means, and that when the engine is operating at full load the pump output is controlled by the first means only. When starting from cold the cold starting enrichment control lever is pulled out thus causing the arm 31 to swing in a clockwise direction and causing the extension 30 to contact the extension 29 of the pump output control lever 25 and to operate the latter. The engine is then switched on and when it turns the pump 5 will pump fuel to the nozzle 1. As soon as the engine has started the cold start enrichment control lever may be released and the engine fuel requirements will be controlled by the automatic fast idle and enrichment control device 44. The control side of the diaphragm unit 36 is in communication with the atmosphere through the pipe 43 and the port 53. Under these conditions the diaphragm holds the adjustable operating link 35 in a lower position so that the part load cam 22 maintains the pump output control lever in a position where it controls the pump in such a way that a sufficiently rich mixture is fed into the manifold 2 during the warming up period. As the engine warms up the thermostatic control element operates to move the thrust rod 49 outwardly thereby causing the slide valve member to close the pipe 43 and eventually the pipe 45 and the stub pipe 52. The control side of the diaphragm now becomes governed by the reduced pressures obtaining in the manifold 2 through the pipe 37, the bleed valve 39 being closed during all these operations. The reduced pressures obtaining in the manifold 2 cause the diaphragm to rise thus lifting the operating link 35 and the part load cam 22 and allowing the pump output control lever to move in a clockwise direction whereby the fuel input to the engine is reduced. As the speed of the engine rises the Watt type governor in the housing 7 pushes the thrust pin 8 outwardly of the housing thus causing the bellcrank 10 to turn in an anti-clockwise direction. The cam follower 12 acting on the cam surface 14 causes the cam arm 15 to pivot in a clockwise direction about its pivot 16 thereby pulling- the adjustable link 18 to the right. Movement of the link 18 to the right causes the arm 19 to swing in an anti-clockwise direction about its pivot 20 thus pulling the part load cam 22 to the right and allowing the pump output control lever 25 to move further in a clockwise direction so as to reduce the fuel input to the engine. During full load requirements ofthe engine the movement of the pump output control lever 25 is governed by the Watt type governor acting on the part load cam 22. Any desired arrangement of nozzles may be employed. A distributing device may be employed to feed a multiplicity of nozzles. The nozzle 1 may be positioned so as to inject fuel towards the throttle plate 3 so that the pipes 6 and 37 will effectively be interchanged. A small bleed valve may be incorporated in the air manifold directly opposite the injection nozzle. It may be desirable to have' a valve controlled by the -throttle linkage for connecting the control side of the diaphragm to atmosphere. The pump 5 may be a reciprocating pump such as that described in Specification 701,249.