GB652884A - Improvements in or relating to spray carburettors for internal combustion engines - Google Patents

Abstract

652,884. Spray carburetters. CARTER CARBURETOR CORPORATION. Feb. 24, 1948, No. 5517. Convention date, Dec. 10, 1942. [Classes 7(iii) and 7(vi)] The cylinders of a multicylinder engine are arranged in groups connected to separate intake manifolds 10, 11, Fig. 1, fed by twin carburetters 13, 14 with fuel nozzles 24, Fig. 3, respectively from passages 16, 17, Fig 2, Fuel is metered through orifices 20, 21 controlled by metering valves 39, 43 operated to close the orifice 20 to put the carburetter 13 and manifold 10 out of action at idling and to close both orifices 20, 21 at over-running. A device 305, Fig. 3, is provided which is operated, when the valve 39 is closed, to withdraw fuel from the passage 16, and return it thereto immediately valve 39 is opened, to prevent waste of fuel and to facilitate bringing the carburetter 13 back into action. The'valves 39, 43 carry small magnets 54 to provide a snap-action opening and closing, and the valve-stems 18, 19 are connected through lost-motion connection 41, Fig. 4, to a rod 33 operated by a spring-loaded piston 34, actuated by the suction downstream of the throttle valve 26 transmitted through a passage 37. When the throttle valve 26 is closed for idling the suction, e.g. 10 in. mercury, moves the piston 34 against a spring 38 and carries the valves 39, 43 downwards so that valve 39 closes the orifice 20 and puts the manifold 10 out of action. At a higher suction, e.g. 18 inch mercury, during overrunning the piston 34 compresses a second spring 55 and its lost motion connection with the valve 39 allows it to move down further to cause the valve 43 to close the orifice 21 and put the manifold 11 also out of action. The device 305 comprises a spring-pressed piston 306 which is drawn down by the suction transmitted through a pipe 303 at the instant at which the valve 39 closes, whereby all the fuel in the passage 16, the nozzle 24 and the idling passage 31. Fig. 2, is drawn through the orifice 310 into the cylinder 305. When the throttle valve is opened, the drop in suction allows the valve 39 to open, and the spring 307 expels the fuel from cylinder 305 as a jet through orifice 310, refilling the fuel passages and bringing carburetter 13 straight back into action. The carburetters may include an automatic choke mechanism provided with means holding the throttle valve slightly open at starting and warming up. In this position an arm 49, Figs. 2, 4, rotated by a link 45 from the throttle valve operating mechanism 44 raises the rod 33 and opens the valves 39, 43 so that both carburetters are in operation at starting. Acceleration pumps may be included in the carburetters. Specifications 472,090, 531,244, [Group XXXV], and 652,883 are referred to.