GB617746A - Improvements relating to carburettors - Google Patents

Abstract

617,746. Spray carburetters. ARVASTSSON, O. A. Nov. 1, 1946, No. 32524. [Class 7 (iii)] A carburetter for internal combustion engines comprising a mixing chamber having a main air inlet and an outlet for connection to the engine intake manifold, a fuel nozzle opening into the mixing chamber and communicating with a float chamber, a heating chamber fitted with heating means and surrounding the float chamber and having an air inlet and an outlet which latter opens into the mixing chamber, is provided with a tubular member which constitutes the air outlet from the heating chamber and surrounds the fuel nozzle in the mixing chamber so that the heated air flowing from the heating chamber vaporizes the fuel from the nozzle and mixes therewith before the mixture formed mixes with the air flowing into the mixing chamber through the main air inlet thereof. Fuel enters the float chamber 1 through a valve 8 under the control of the float 9. The heating chamber 10, with an air inlet 11, is fitted with electrical element heating 12 and has an air outlet opening into the mixing chamber 2. The heating chamber 10 can also be heated by exhaust gases which flow in a channel 13, arranged externally of the former and provided with an inlet 14 and an outlet 15. From the float chamber 1 the fuel passes through a passage 16 and an adjusting valve 18 to nozzle 17, which projects centrally from the base of the mixing chamber 2. The heating chamber 10 has an extension 19 in the top wall of which is formed the tubular member 20 that surrounds the nozzle 17 in addition to extending above it, thereby forming the outlet into the mixing chamber 2 for the air from the heating chamber 10. The electrical heating elements 12 are only intended to be used before and during starting of a cold engine. During normal engine operation the air in the heating chamber 10 is heated by the exhaust gases which flow through the channel 13 around the heating chamber 10, the fuel in the float chamber 1 being also heated at the same time. The air from the heating chamber 10 enters the mixing chamber 2 at the base of the tubular member 20 and passes the nozzle 17, thus vaporizing the fuel before this mixture combines with the air entering through the main inlet 3. In a modification an additional fuel passage 21 may branch off from the nozzle fuel passage 16 and communicate with the mixing chamber 2 through a suitable control valve 22.