Patent GB-159846-A (GB)
Title: Improvements in or relating to carburetters for internal combustion engines
IPC: F02M1/16
Filed: 1921-03-05
Abstract: 159,846. Stromberg Motor Devices Co., (Assignees of Mock, F. C., and Gustafson, C. J.). March 5, 1920, [Convention date]. Spray carburettors. - In carburettors, e.g. of the plain tube type as described in Specification 110,807, means are provided to ensure a supply of mixture during the transition period from slow to normal running, such means comprising two accelerating wells one of which is subject to the suction in the mixing chamber and the other to that in the induction pipe. Means are also provided to control the fuel flow to the nozzles and to admit and control air to mix with the jets of fuel issuing from the nozzles. The casing 10 has an air inlet 11 and a mixture outlet 12 both valve-controlled and encloses a choke tube 13 near the throat of which discharges a second choke tube 15 into which fuel is delivered by the main nozzle 19. The choke tube 15 is held in an arm 16 secured by a screw 16' and prevented from tilting by a pin 15<1>, Fig. 4. The float chamber 21 has a pocket 24 in which is located a valve 29, Fig. 5, which controls the fuel to the main nozzle through passages 28, 26, 25, 27, Figs. 3 and 5. To supply an excess of fuel to facilitate starting a second pocket 32, Figs. 5 and 6, communicates with the main jet passage 27 through a passage 30 controlled by a spring-pressed valve 31 which may be actuated by the driver through a connection to a lever on a spindle 39, a cam 37 on which is adapted to force down the valve spindle 34. The main nozzle 19 is, in its lower part, of reduced diameter to form with the surrounding casing 41 an accelerating well 42 which communicates with the interior of the nozzle through holes 43, 43<1>, those at the higher level 43 being greater in number. The holes 43 are in communication with an air supply, taken preferably from the interior of the carburettor, e.g. at 45, Fig. 4, through a passage 44<1> controlled by a valve 46 loaded by a spriig 47 and actuated from the throttle valve 20 through a forked lever 53 and adjustable head 52. As the throttle is opened the air valve is closed and vice versa, but in its closed position air may enter through passages 48, 49. Fuel for slow running is delivered near the edge of the throttle valve through a nozzle 56, Fig. 3, supplied from the main nozzle through a passage 66 and tube 61 and air, to mix with the fuel, is taken from the mixing chamber through holes 67, 68 controlled by a valve 69. To ensure a supply of fuel during the transition period referred to above, a second accelerating well 70, Figs. 4 and 6, is provided which delivers fuel into the choke tube 15 through a nozzle 71. The well is in commounication with the pocket 24, Fig. 6, through a. passage 72 and with the induction pipe above the throttle through a tube 73 leading to the bottom of the well. A small air inlet is provided at 80. A sleeve 74 around the tube 70 is cut away opposite the nozzle 71 to form a ledge 76 past which air may flow from an inlet 78. Fuel passes to the nozzle through duct 77. During slow running fuel is raised in the tube 73 and is delivered through nozzle 71 when the throttle opening is increased; at the same time the air valve 46 tends to close and restrict the air flow to the nozzle 19 which then begins to deliver fuel, a plentiful supply of which is provided by the well 42 feeding through the holes 43<1>. A modified construction of the priming valve 31 is also described in which the valve is enclosed in a tube having small fuel inlets therein, the valve stem in its upper part being hollow and open to atmosphere.