GB413306A - Improvements in or relating to carburettors for use with internal combustion engines - Google Patents

Abstract

413,306. Spray carburetters. GRACE, C. J., Institute of Mining & Metallurgy, Cleveland House, City Road, London. Jan. 11, 1933, Nos. 997 and 17320. Addition to 392,929. [Class 7 (iii).] An unbalanced throttle valve 14, which in the parent Specification is limited in its opening movement by adjusting a stop and controls a valve in the fuel supply passage, is, according to the invention so curved and arranged that air passes only on one side of it. When the valve is fully open, it enters a recess 16 in a rectangular air intake 10. The valve opens against the resistance of a spring 84 and its opening movement is limited either by a manually adjustable stop or by an auxiliary manually controlled balanced valve which may carry a stop member to limit positively the opening of the valve. Fuel is supplied through ducts 40, Fig. 5, to a passage 36 terminating in a valve controlled duct 34. A jet from the duct traverses a recess 44 in a block 42 and passages 24, 22 which discharge through a narrow transverse slit in a nozzle 20. The fuel issuing through the duct 34 is regulated by a valve 56 which is carried by a piston 50 controlled from the valve 14 through links 64, 70, 72. The fuel supply may be rendered independent of the suction by a calibrated orifice 30 which is open to the atmosphere and serves as an air inlet to the passages 24. When the valve 14 is closed an extension 52 carried by the piston 50 cuts off communication between the passage 32 and the recess 44. The cylinder in which the piston 50 is housed is connected through passages 60, 58 with the induction pipe above the throttle and the size of the passages is such that until the throttle is half-open the piston and cylinder act as a dashpot arrangement, and on further opening of the throttle, the suction transmitted to the top of the piston provides an additional moment tending to open the throttle. To provide for slow running, a groove 92 is formed in the upper edge of the valve 14. A spring-loaded valve 94 prevents excessive suction from being applied to the unbalanced valve. In a modified construction, to provide an additional moment tending to open the throttle, in place of, or in addition to the piston 50 and cylinder 48 a vane is formed integral with or attached to the throttle valve. The vane extends into a cylindrical recess formed in the wall of the air intake pipe and suction is applied to one side of it, the other side being exposed to atmospheric pressure.