GB600895A - Improved means for controlling the mixture of fuel and air supplied to internal combustion engines - Google Patents

Abstract

600,895. Gas turbines. BAINES, J. K. W., FLETCHER, K. A., and BURNS, Ltd., J. Dec. 14, 1945, No. 33945. [Class 110 (iii)] [Also in Groups XXVII and XXXV] In an apparatus for controlling the proportions of air and fuel. in combustible mixtures, the grid bias of a thermionic valve in an amplifier is varied in accordance with the composition of the exhaust gases, the amplifier output controlling the air or fuel supply electromagnetically. Variations in the amount of oxygen in the exhaust gases alter the resistance of a heated tungsten filament C situated in a byepass B of the exhaust pipe A and cause fluctuations in the output of an amplifier D which actuate an electromagnet G to control the fuel supply from a pump H to the nozzle L. The filament C forms one arm of a Wheatstone's bridge CMNO, Fig. 4, the arm Q of which is earthed at R and connected to the control grid S of a pentode T, the anode of which is connected to the grid U of a tetrode V having two relay coils W, X in its anode circuit which control the circuits of solenoids 3, 4, actuating a fuel metering valve 7 suspended mid-way therebetween from a spring 6. Variable resistances 9, 10 adjust the relative forces exerted by the solenoids 3, 4, and the amplifier is supplied with current from a power pack E having a switch operated by the ignition key. In a modification, the electromagnet actuates the control-rod of a Bosch or C.A.V. pump and the device may control a carburetter, e.g. of the S.U. type, the suction plunger being controlled by the solenoids. The tungsten filament may be replaced by a selenium cell and infra-red beam, the intensity of which varies with the amount of carbon or unconsumed fuel in the exhaust gases.