GB420295A - Improvements relating to carburetors for internal combustion engines - Google Patents

Abstract

420,295. Spray carburetters. BENDIX AVIATION CORPORATION, 105, West Adams Street, Chicago, U.S.A. May 6, 1933, No. 13239. Convention date, May 7, 1932. [Class 7 (iii)] A carburetter body formed in two sections has a float chamber and a double Venturi cast integral with one of the sections. A downdraught carburetter comprises an upper body portion 8, preferably of aluminium alloy and formed by die casting, and a lower body portion 9 preferably of cast iron and formed as a plain tube with relatively thin walls and separated from the upper portion by a non- conducting gasket 10. A choke valve 13 mounted on a shaft 14 is provided with a poppet valve 15. The upper section is cast with a float chamber 21 and also with an inner Venturi 36 and an outer Venturi 34, this being made possible by a fin 38 which contains the nozzle in the form of a tubular member 45 held in place by a metering plug 53. Tube 45 is cut away on its outer surface at 54 to provide an air-bleed passage, which communicates at one end with the bore of the tube through ports 56, and at the other end with the main air passage through a duct 60. The tube is also cut away circumferentially at 62 to provide communication with an idling duct 64, 66 which leads, through passage 72, Fig. 4, to a nozzle 76 beyond the throttle valve 19. The throttle is actuated through a lever 82 and the other end of the spindle has an arm 88, Fig. 5, connected to one arm 92 of a jointed lever the other arm 93 of which is connected to the rod 98, Fig. 4, of an accelerating pump. The members of the jointed lever turn about a pin 94, Fig. 3, and are normally held by a spring 97 so that the arm 92 is in contact with a stop 96 on the arm 93. On rapid opening of the throttle 19, the lever arms are relatively displaced against the tension of the spring with the result that the plunger of the accelerating pump has a slow and prolonged movement. The cylinder 102 of the accelerating pump is cast with the upper body section 8 and communicates with the float chamber through a port 103, Fig. 5. The lower end of the cylinder is connected through a port 111 with an accelerating-fuel nozzle 112, Fig. 4. In a modification, Fig. 8, (not shown) a second fin is provided in alignment with the fin 38, and the inner Venturi is provided at its upper end with a cap which constitutes the main nozzle. The cap is recessed on its outer surface to form a chamber registering with the fuel passage and communicating with the Venturi through holes in the cap.