GB889441A - Improvements in means for supplying a supplementary or auxiliary liquid to the fuel supply of an internal combustion engine - Google Patents

Abstract

889,441. Carburetters. WILKINSON, H. S., and JACKSON, D. June 13, 1958 [June 14, 1957], No. 18772/57. Class 7(3). A device for automatically dispensing or injecting a liquid additive into the fuel supply of an internal combustion engine comprises a suction pipe leading from a source for the additive into the carburetter of the engine at a point before the throttle, the suction pipe being connected to an air bleed pipe having an end adapted to be opened and closed by a valve operatively connected to a pressure sensitive element connected to the carburetter or engine manifold after the throttle so that the degree of opening of the air bleed pipe by the valve varies with changes in pressure in the carburetter or engine manifold after the throttle and the amount of additive dispensed or injected into the fuel supply is increased with the load imposed on the engine. As shown the device comprises an injecor pipe 1 the end 1b of which is submerged in an auxiliary additive (in this case water) in a float chamber 4 which is fed from a tank (not shown) either by gravity or by a suitable pump. Branched into the inlet pipe 1 is an air bleed pipe 5 the outer end of which has an orifice 6 with which a tapered needle 7 cooperates. The needle is operable by a diaphragm one side of the diaphragm being connected by a pipe 10 to the manifold 11. When the throttle is opened (for example at full load) the depression in the manifold is reduced and the spring 8 is able to push the needle 7 into the orifice 6 thus closing it. Consequently the suction at the choke tube 2 will draw water from the float chamber 4. A cable 13 is provided for controlling the spring 8 so that it is possible to control at what manifold depression the injector starts to operate. A non-return valve may be fitted in the inlet pipe 1 between its junction with the pipe 5 and the float chamber. The needle 7 may be constructed so that it acts as a metering device in the inlet pipe 1. Bellows or pistons may be used in place of a diaphragm. The control lever for regulating the sensitivity of the air jet may be operated in conjunction with the conventional choke control or it can be thermostatically controlled. An accelerator pump may be incorporated to obtain instantaneous injection response to the throttle. A small quantity of air may be fed continually into the air bleed pipe. The device can be made to operate in conjunction with a variable choke a constant vacuum carburetter either vertical sloping or horizontal. The device can be used with multi-carburetter installations using a common tapered needle and air jet and an individual float chamber for each carburetter. Alternatively one float chamber can be used in conjunction with a branched inlet pipe. The liquid additive may be methanol, hydrogen peroxide, upper cylinder lubricant, a decarbonising fluid or water or a high octane fuel when that supplied by the carburetter is a low octane fuel.