GB471395A - Improvements in or relating to carburettor throttle valve control means - Google Patents

Abstract

471,395. Spray carburetters. INTERNATIONAL HARVESTER CO. OF GREAT BRITAIN, Ltd. (International Harvester Co.) Sept. 3, 1936, No. 24136. [Class 7 (iii)] To avoid an excessively high intake vacuum during deceleration of an engine, the closing of the throttle is retarded by means operated by the suction on the engine side of the throttle. In the construction shown, a slotted clamp 22 secured to the shaft 15 of the throttle valve 14 limits the angular movements of a lever 24 freely pivoted on the shaft. The lever 24 carries a pin 25 sliding in a slot 26 in a control member 28 which is secured to a diaphragm 32 in a fixed casing 31. A second casing 33 containing a spring-pressed diaphragm 37 is secured to the casing 31 by a tube 34 which contains a piston 42 held, by a spring 44, against a nozzle 39 carried by the diaphragm 37. The high vacuum momentarily created by sudden movement of the throttle valve 14 towards its closed position is communicated to the casing 33 through a pipe 36 and displaces the diaphragm. When the piston 42 has moved to the end of the bore 43 the diaphragm withdraws the nozzle 39 from the piston and the suction is transmitted through passages 41<1>, 46 to the diaphragm 32 which moves the control lever 28 to bring a screw 30 into engagement with the lever 24 to prevent further closing of the throttle. As the speed falls the vacuum drops and the control lever 28 permits the valve to close. When the piston 42 reaches the position shown, by pressure of the tube 39 against its end, air is bled through passages 48, 45 which may be metered to continue the slow return movement of the diaphragm 32. The throttle valve may be controlled by a single diaphragm.