GB983730A - Carburettor - Google Patents

Abstract

983,730. Spray carburetters. BENDIX CORPORATION. May 1, 1963 [June 4, 1962], No. 17212/63. Heading F1B. In a constant-suction type carburetter with a suction-actuated sliding piston choke valve 26, Fig. 1, a suction-actuated air-bleed device 34 reduces the suction acting in chamber 23 at certain operating conditions to produce enrichment of the mixture. In Fig. 1 the device 34 includes a suction-actuated piston 41 with a recess 42 which connects the bleed port 37 into chamber 23 to an atmospheric port at high power outputs when the intake manifold suction is low. The reduction in suction in chamber 23 causes lowering of the piston 26 which increases the suction on the fuel orifice 18 to enrich the mixture. At part-throttle conditions when the intake manifold suction is high, the piston 41 is pulled down to close the port 37 and the piston 26 returns to its normal position. In a modification, Fig. 4, a suction actuated piston 77 is surrounded by a sleeve 66 rotatable by a thermostat 76 responsive to engine temperature, the amount of air bled into the suction chamber 23 being controlled by co-operation of a slit 82 in the piston with a slot 73 in the sleeve. At cold starting the piston 77 is raised and sleeve 66 is rotated so that the slit 82 engages the widest part of slot 73 to obtain maximum enrichment. When the engine fires, the manifold suction lowers piston 77 to move slit 82 partly out of register with slot 73 so that less air is bled into chamber 23 to reduce the enrichment. As the engine temperature increases, the sleeve 66 is rotated until the slot 73 is out of register with slit 82 and the air bleed is closed. In a further modification the air bleed is controlled by a needle valve which is actuated jointly by a suction-actuated piston and manual or temperature responsive means.