GB251403A - Improvements in and relating to carburettors for internal combustion engines - Google Patents

Abstract

251,403. Schwab, F. A., and Smith, R. March 23, 1925. Vaporizers, external; spray carburettors. - Light or heavy fuel is mixed with a small quantity of air and the rich mixture is passed through an exhaust-heated chamber to the main mixing- chamber where it is diluted with a controlled amount of air before passing to the cylinders. The fuels are in adjacent wells the flow to which from the tanks as well as the flow from which to the spraying orifice are controlled by a rotatable plug valve. A casing 10, Figs. 9 and 10, contains two wells 11 for the respective fuels, each well having a float-controlled needle valve 15 for controlling the flow of fuel thereto through fixed ducts 19, 13 to ducts 64 arranged at right-angles to one another in a rotatable plug valve 62, Fig. 5. Circumferential grooves 65, Fig. 5, in the valve register with outlet ports 61 from the wells 11, and from each groove a recess 66 leads axially to a duct 22, Figs. 8 and 9, controlled by a needle valve 64. The duct 22 discharges the fuel in use into a tubular part 41 to which a small quantity of air may be admitted under an adjustable sleeve 44. The needle valve is adjusted by a pin and slotted rod. The rich mixture passes by way of conduit 49 to a heater comprising a part 50, Figs. 6 and 7, held against the exhaust manifold 51 by a strap 51<1> so as to form a chamber 52 to which the rich mixture is conducted by an inlet 53, said mixture after being heated passing through outlet 54 and bv way of pipe 27 to the main mixing chamber 24, Fig. 8. This is fitted to the top of casing 10 and is provided with an automatic air valve 30 loaded by a spring adjustable by a bush 32, the opening of the valve being capable of being limited, or prevented entirely, by an arm 56 adjustable against a spring from outside. The usual throttle valve is provided at 37. The valve 62 being set for the appropriate fuel, the latter enters the well 11 through ducts 19, 64, 13 and returns through duct 61 to groove 65 whence it passes along recess 66 to duct 22 upon discharge from which it is mixed with air. A modified form of heater is described comprising a box with tortuous passages, located in the exhaust manifold and secured thereto by inlet and outlet pipes screwing into bosses in the box.