GB278425A - Improvements in or relating to carburetting apparatus for internal combustion engines - Google Patents

Abstract

278,425. King, B. O. July 5, 1926. Spray carburettors. The column of air passing through the carburettor is utilized to create a static depression upon and over a fuel orifice outside the air passageway to withdraw fuel from said orifice, and is then contracted to produce an intensified depression which is utilized to lift the fuel withdrawn by the static depression and to deliver it from outside said passageway into the contracted column of air. A main air passageway comprises a convergent portion 1, a parallel central portion 2, and a divergent portion 3 provided with a flange 5 for attachment to the manifold. The conical portion 1 has a cylindrical extension 1<1> provided with holes 11 shielded from the moving air stream by a, flanged ring or nozzle 10<1>, which serves as an air-metering inlet. The contracted portion 2 is provided with a throttle valve in the form of a sliding plate 6, the control edge of which may be straight or curved to the same radius as the interior of the part 2. The casing 12 comprises a float chamber 14, from which fuel may issue through an orifice 15 into a well 19 formed by walls 20, 20<1>. The well communicates with a chamber 21 through a passage which may be controlled by a valve 22 with actuating arm 27. The valve 22 may be dispensed with and the holes 11 suitably calibrated. Depending into the well 19 and arranged immediately above the orifice 15 is one end 23 of a passage 24 through which the fuel is lifted and delivered through an outlet 25 into the air flowing through the throat 2. Below the throttle 6 and on the side opposite to the outlet 25 is a slot 26 which leads through a duct 26<1> to the chamber 21. The slot 26 is more or less shielded from the effect of the moving air stream until the throttle is completely opened. The carburettor is formed in halves separated by a gasket 28. The air flow produces in chamber 21 a static depression which raises fuel into the well 19. The increased depression existing at the outlet 25 draws air from the well through the passage 24, which air carries with it any fuel that may " well up " irom the orifice 15. The extent of the depression in the, well can be regulated by the valve 22. The area of the passage 24 is somewhat larger than that of the orifice 15 and the two are separated by a distance equal to about two or three times the bore of the mouth 23. The fuel-carrying capacity of the duct 23 - - 25 must always be greater than the delivery capacity of the orifice 15: in other words the bore of 15 multiplied by the static depression is less than the bore of 23 - - 25 multiplied bv the difference in the depressions existing in the throats 10' and 2. As the throttle is fully opened the depression in throat 2 is transmitted through slot 26 and duct 26<1> to chamber 21 and well 19, thus increasing the fuel flow. The metering of the air and fuel is not affected to a.ny appreciable extent by air vibration. The Provisional Specification states that the air passage may be, horizontal and that more. than one fuel orifice each with a separate air passage may be provided.