Patent GB-311444-A (GB)
Title: Improvements in carburettors
IPC: F02M7/22
Filed: 1928-02-11
Abstract: 311,444. Monosmith, C. E., Monosmith, D. J., and Monosmith, O. B. Feb. 11, 1928. Spray carburettors.-The valve controlling the fuel discharge port is capable of movement in two directions at right angles to one another one movement, due to its connection to a suction-actuated air valve, producing a constant ratio of air to fuel, the. other movement being a manual adjustment to vary the value of the ratio. The main passage is formed by a rectangular casing 1 surmounting which is an auxiliary chamber 8<1> formed by walls 2 and a cover 3. A rectangular throttle valve 5 mounted on a spindle 5<1>, and a rectangular suction-actuated air valve 4 divide the main passage into spaces 7, 8, 9 subjected respectively to atmospheric pressure, low vacuum and high vacuum. The auxiliary chamber 8<1> is in communication with the space 8 through an aperture 6. A fuel conduit 11 is secured by a plate 13 and screws 14 to an enlarged part 27 of a tubular member which extends transversely into the chamber 8<1> and has a fuel discharge port 15 adapted to be controlled by a port 18 in a sleeve 16. This sleeve is loaded by a spring 17, is adjustable axially by a screw 25 and is provided with an arm 23 connected by a link 22 to an equal and parallel arm 21 on the spindle of the air valve 4. The fuel is discharged into a semi-cylindrical passage 19 between the sleeve 16 and upstanding portions 1<1> of the casing 1 and the mixed fuel and air issue through an aperture 20 into the main passage on the high vacuum side of the throttle valve. Atomization of the fuel and its mixing with the air, as well as a high velocity of air past the aperture 20 at nearly closed positions of the throttle valve, are obtained by providing a lug 28 one end of which is bevelled and projects over the aperture 20. The part 27 is provided with an arm whereby the tubular member may be independently adjusted for idle running. The air valve 4 is loaded by a spring 24 the tension in which is such as to maintain in the space 8 a lower limit of vacuum of about two ounces and an upper limit of about one pound below atmosphere, these limits ensuring that the power of the engine at full load is not limited and that the turbulent flow of the fuel is preserved. The air and fuel inlet openings are both of rectangular form so that a constant ratio of air to fuel is maintained and the value of this ratio may be varied by moving the sleeve 16 by the screw 25. To ensure that the air inlet 30 is proportional to the angular movement of the valve 4, the casing 1 is off-set at 35. In a modification, Fig. G, not shown, the air valve 4 coacts with an adjustable pivoted blade in the lower wall of the casing 1, by which means the initial or closing position of the air and fuel valves can be regulated. In a further modification, Figs. 7 and 11, the fuel valve is moved axially by the air valve and is rotated manually to vary the air-fuel ratio. The air valve 4<1> is connected by a link 21<1> to one of several holes 22<2> in a lever 22<1> pivoted at 38 to an adjustable rod 40, the other end of the lever bearing against a collar 44<3> loosely mounted on a cylindrical rod 16<1> loaded by a spring 24<1> and constituting the fuel valve. This rod enters a casing 10<1> slotted at 15<1> and is cut away along a diameter at 18<1> to provide a control edge for the slot. The interior of the casing communicates with at fuel supply duct 11<1> carried by a member 1<2> which is spaced from the casing 1 to provide a passage 19' which communicates with the space 8 through an aperture 8<2>. In order to rotate the fuel valve to vary the air-fuel ratio, the rod 16<1> has clamped thereto a member 44, a pin 46 on which is engaged by lugs 48 on a piece 47 movable transversely by a rotatable screwed rod 49. The free end of piece 47 is supported by a rod 52. The air valve 4 is stated to act as at flame trap in the event of a back-fire.