GB558783A - Improvements in or relating to carburetters for internal combustion engines - Google Patents

Abstract

558,783. Spray carburetters. BENDIX AVIATTON CORPORATION. July 17, 1942, No. 9991. Convention date, Oct. 3, 1941 [Class 7 (iii)] In a carburetter having an air choke 12 which is closed when the engine is cold by a bi-metallic strip 20, and opened by suction, a connection is provided between the air choke and the mixture throttle 14 which serves to limit the opening of the choke while the engine is being cranked for starting, to hold the choke in a partly-open position during warming-up, and to release the choke so that it may be fully opened by the suction when the inner throttle is opened a predetermined amount. An arm 46 on the choke 12 is connected by a rod 44 to an arm 42, rocking about a stud 40 and formed with a lug 54 engaging between projections 56, 58 on a stepped cam 38, also mounted on the stud 40 and having its stepped face engaged by a stop 36 carried by a lever 28 connected to the throttle spindle 22 and to the accelerator rod 30. A pawl 64 mounted on a boss 25 is formed with a shoulder 68 to engage a fixed pin 70, and with an arm 62 and lug 63 for co-operation with a pin 66 on the cam 38, the arm 64 of the pawl engaging the arm 34 of the lever 28. A wedge 74 on the lever 28 engages a second pin 72 on the cam 38. When starting the engine from cold, the parts are in the position shown in Fig. 3, with the choke closed and the throttle 14 held slightly open, by the stop 36 engaging the highest step of the cam 38, so as to provide sufficient mixture during cranking, the opening of the choke due to the suction caused by cranking being limited by the stop 58. When the engine starts and the throttle is opened farther, the stop 36 releases the cam 38 and the air choke, which is opened by the suction as the engine warms up. When the bi-metallic strip allows the choke to open sufficiently to release the side of the arm 62 from the pin 66, the arm swings by gravity into the position shown in Fig. 1, so that the lug 63 comes into line with the pin 66 to limit the amount by which the choke can be closed by the bi-metallic strip, and maintain the moderately-rich mixture for warming-up. This releasing of the side of the arm 62 from the pin 66 may also be effected by engagement of the wedge 74 with the pin 72 when the throttle 14 is moved towards closed position. A lost-motion connection 48, 50, with spring 52 is provided between the rod 44 and arm 46. The bi-metallic strip may be arranged in a casing 21 connected by a pipe C to an exhaust-heated chamber 23.