GB150019A - Improvements in carburettors for internal combustion engines - Google Patents

Abstract

150,019. Smith, W. S., Salmon, P., and Ellor, J. E. April 23, 1919. Spray carburettors.-Consists in forming the carburettor of two or more nested Venturi tubes, the outer ones being connected to the induction pipe and the inner one having a jet at the throat through which fuel is drawn by the engine section from a reservoir in which the fuel level is below the jet, the usual float chamber being dispensed with. The carburettor shown in Figs. 1 and 4 is suitable for aircraft engines, where the suction lift or negative head of fuel varies owing to the aircraft tilting or to the consumption of petrol. The outer Venturi tube 13 is provided at one end with the usual throttle valve 18 and at the other end with a primary air valve 19 of the Iris type, these valves being simultaneously operated by the lever 20. The inner Venturi tube 15 has its outlet at the throat 17 of the outer Venturi tube, and at the throat of the inner Venturi tube is provided an annular fuel jet controlled by a lever 24, the jet being supplied by pipes 25 leading to a petrol tank 56 through a passage 30 controlled by a needle valve 26. This valve is connected to one side of a diaphragm 27, the other side of which is not only connected by a pipe 31 to an opening 32 at the entrance to the inner Venturi tube, but is also acted upon by a tension spring 33 and dash pot 34. The valve 26 is thus influenced by the difference of pressure existing at two different points of the inner Venturi tube, the flow of petrol being kept constant when the suction lift varies.