Patent GB-137862-A (GB)
Title: Improvements in or relating to carburettors for internal combustion engines
IPC: F02M19/10
Filed: 1920-01-16
Abstract: 137,862. Stromberg Motor Devices Co., (Assignees of Mock, F. C.). Aug. 25, 1915, [Convention date]. Spray carburettors.-The carburettor which in its general aspect resembles that described in Specification 110,807 has two co-axial Venturi tubes one within the other, the outlet of the smaller tube terminating approximately at the most restricted portion of the main Venturi tube, and has no automatically movable parts, such as spring-pressed air valves. A carburetting chamber 9 has an air inlet 11 controlled by a valve 14, a mixture outlet 12 controlled by a valve 16 and two Venturi tubes 13, 52, the outlet of the tube 52 being situated slightly above the most restricted portion of the tube 13. Fuel spraying orifices 55 discharge into the Venturi tube 52 just above the most restricted portion thereof. Between the float chamber 19 and carburetting chamber 9 two wells 23, 24 are provided, of which 24, which serves as an accelerating well, is fed from the float chamber through an orifice 67, Fig. 1, and the well 23 which supplies the main and by-pass nozzles is fed through passages 26, 25 controlled by a valve 27. The well 23 contains a thimble 36, Fig. 1, from the reduced lower portion of which a tube 37 leads to a by-pass nozzle 43 delivering into the mixing chamber near the edge of the throttle 16 in its closed position. Air, to mix with the fuel supplied through the tube 37, is drawn through a passage 45 below the throttle 16 and controlled by a valve 46. Around the tube 37 is an annular space 39 which is open to the atmosphere through passages 49, 50, 51. The annular space communicates with the well 23 through an aperture 41 and the thimble 36 through an aperture 40, both apertures being below the normal fuel level X - - X, whereas the spraying orifices 55 are above said level. The accelerating well 24, Figs. 3 and 4, contains a co-axial tube 68 with apertures 74 in the wall thereof at different heights. The interior of the tube communicates at the top through passages 70, 71 and then through tube 72, Fig. 4, with the smaller Venturi tube 52 at 73 above the orifices 55. The well is open to the atmosphere through ducts 75. At closed or nearly closed positions of the throttle valve, fuel collected in the well and passages will issue both from the orifices 55 and nozzle 43 and afterwards from the nozzle 43 alone. As the throttle is opened, the nozzle 43 goes out of and the orifices 55 come into action and air enters at 51 to mix with the fuel on its way to the orifices 55. The suction effect on the fuel jets is augmented by the use of the two Venturi tubes, which at all times produce a sufficient lowering of pressure to extract the fuel required and yet provide a total air passage sufficient fur the demands of the engine. The Specification as open to inspection under Sect. 91 (3) (a) describes also the action of the accelerating well and connexions, shown in Fig. 1 (Cancelled), between the throttle valve, the valve 27 and air inlet valve 14, comprising a threearmed lever 60, 61, 62, cams 57, 65 and rollers 60<a>, 66 the effect of which is to obtain a full fuel now at low and high speeds and a diminished now at intermediate speeds and an increased suction in chamber 9 and consequent increased fuel flow at any desired moment. This subject-matter does not appear in the Specification as accepted, but is described fully in Specification 110,807.