GB350134A - Improvements in carburetters - Google Patents

Abstract

350,134. Spray carburetters. MATHIEU, E., 25 bis, Rue du Chateau, Neuilly-sur- Seine, France. April 14, 1930, No. 11774. Convention date, April 30, 1929. [Class 7 (iii).] In carburetters wherein preliminary spraying of the fuel takes place below the normal fuel level, the fuel being discharged approximately at rightangles to a stream of air flowing through a narrow annular channel at a high velocity, the spraying ducts are formed in a head of ovoid, conical, spherical or other shape, arranged in a converging portion of the spray nozzle, the portion of said head situated downstream of said ducts having a smaller radial size than the portion ahead of said ducts, so as to form a re-entrant surface at the level of said ducts. The fuel-spraying device 5, Fig. 1, comprises a member 20 the upper end 7 of which, preferably of Venturi form, constitutes the nozzle, the lower end fitting over a member 22 having a calibrated orifice 23 fed from the float chamber 1 through a conduit 2. The orifice 23 opens into a passage 24, the upper end 25 of which is cup-shaped. The passage 24 receives a tubular member 26 having an ovoid or other shaped head 27 which co-operates with the edge of a cup-shaped part 25 to form an annular spraying orifice 28 which discharges fuel across a narrow annular air stream flowing at high velocity in the space 30 between the part 25 and the member 20. Air, to produce spraying of the fuel, enters by way of a conduit 6, passage 42, and large orifices 29. A byepass or slow-running device which delivers mixture through a duct 14 to a point 43 near the edge of the throttle 9 in its closed position, is constructed on similar lines to the main sprayer, fuel being supplied through a conduit 10 and spraying air through a duct 13, communicating with the float-chamber air space which is open to the atmosphere. The head 7 may have various shapes, and the fuel may be sprayed through a number of orifices instead of a slot, and examples of these modifications are given in Figs. 2 to 7 (not shown). As shown in Fig. 8, the member 7 may be held in place by the inturned edge 49 of a sleeve 50 which is screwed on to the part 51. The sleeve has air-inlet apertures 52, and between the sleeve and member 7 is a tubular member 53. The fuel may be sprayed from the periphery through an annular slot 59, Fig. 10, towards the centre, and the core 58 may also be provided with fuel-spraying conduits 61, 60. A number of spraying devices 69, 70, 68, Fig. 15, may be arranged in series, the mixture being discharged into the air passage 8 through an annular slit 72 which spreads the mixture. This spreading is produced in the form shown in Fig. 1, by the Venturi outlet of the nozzle 7, and further types of spreading devices, particularly for horizontal carburetters, are described with reference to Figs. 11 to 14 (not shown). The calibrated orifice 23 may be supplemented by one or more connecting orifices 80, Fig. 16, the flow through which is kept down at high speeds by the action of the spraying air through apertures 29. The correcting orifices may be arranged otherwise as described with reference to Figs. 17 and 18 (not shown). To prevent an excess of fuel from being taken up by the spraying air at starting, the reserve supply of fuel is contained in recesses or chambers such as 41, Fig. 19, protected against direct effect of the spraying air by a partition 90. At starting, the spraying air flows through apertures 92 expelling the fuel above the partition ; it then forces fuel in spaces 41, 42 through duct 95 into conduit 24 and through the spraying slit 28. A correcting orifice opens into the duct 95 in a modification, Fig. 9 (not shown). In further modifications, Figs. 10 and 21 (not shown), the correcting fuel flows through a conduit parallel to conduit 24, and may issue through the main sprayer 28, or through an additional sprayer. In cases where the fuel is supplied through different paths, a light fuel may be supplied through one path to facilitate acceleration, and a heavy fuel through the other. The Specification as open to inspection under Sect. 91 (3) (a) describes also a modification somewhat similar to that shown in Fig. 10, but wherein fuel is sprayed only from the periphery towards the centre, the part 58 being solid. This subjectmatter does not appear in the Specification as accepted.