GB420715A - Improvements in carburettors for internal combustion engines - Google Patents

Abstract

420,715. Spray carburetters. SOC. ANON. SOLEX, 190, Avenue de Neuilly, Neuilly-sur- Seine, France. Oct. 20, 1933, No. 29113. Convention date, Nov. 25, 1932. [Class 7 (iii)] In carburetters having an independent carburetter for effecting starting and slow running while cold, such as is described in Specification 357,310, auxiliary means are provided to render the starting mixture suitable when operating at unusually low temperatures. The auxiliary means may (1) comprise a second starting-carburetter which operates in addition to, or instead of, the first starting carburetter, or (2) alter the regulation of the starting-carburetter, or (3) may heat the air entering the starting-carburetter. As shown in Fig. 1, a float chamber 1 supplies fuel through a passage 7 to a main jet 3, a jet 2 which discharges into a slowrunning passage 4 for use when the engine is hot, and to a starting-carburetter through a calibrated orifice 8 in a well 9 open to the atmosphere. The starting mixture is fed through a passage 13, controlled by a valve 14, into the induction pipe 5 above the throttle valve 6. The passage 7 also supplies fuel to a second starting-carburetter through a calibrated orifice 16 in a well 17 open to the atmosphere, and the mixture formed therein is fed through a passage 21, controlled by a valve 22, either into the passage 13 beyond the valve 14, or directly into the induction pipe. A control rod 23 is connected to a lever 24 operating the valve 22, and the lever 24 is connected by a spring 25 to a lever 26 operating the valve 14. During starting at normal temperatures, the valve 22 remains closed and the valve 14 is fully open, the lever 26 contacting with an abutment 27; but at abnormally low temperatures, the rod 23 is pulled further to expand the spring 25, opening the valve 22, and bringing the second starting- carburetter into action. In the modification shown in Fig. 5, the two starting-carburetters are controlled by a port 30 in a valve 29. When a lever 31 on the control rod 23 contacts with a resilient abutment 32, the passage between the starting- carburetter and the tube 13 is fully open, and further operation of the control rod 23 at abnormally low temperature brings the second starting-carburetter into operation. The valve 29 may be arranged to replace the starting-carburetter by the second starting- carburetter at abnormally low temperatures. The auxiliary means may alter the regulation of the starting-carburetter by supplying at abnormally low temperatures, additional fuel. The jets 10, 18 are parallel and immersed to different levels in the same well, so that as the valve 29 is opened, the jet 10 goes out of action and fuel is supplied under a greater head of pressure. In a modification, Fig. 8, the jet 10 is arranged above the jet 18, and after the control rod 23 has contacted with the abutment 32, further movement causes an arm 36 on the lever 31 to engage with a spring- pressed member 37 and superpose the jet 10 on the jet 18, so that the feed of fuel to the starting-carburetter takes place under a fuel head H instead of a fuel head h. In a further modification, Fig. 9, when the abutment 32 is compressed, a projection 41 on the lever 31 opens a needle valve 40 controlling a calibrated orifice 16 opening into the well 9 to supply additional fuel. The needle valve 40 or the valve 22 may be controlled automatically, e.g. by a thermally-responsive element dependent on the expansion of water at its freezing point. In another modification, the air supply to the starting-carburetter is heated electrically when the temperature is abnormally low. When the abutment 32 is depressed, its rod closes contacts in a circuit which includes a heating-resistance surrounding the air inlet of the starting-carburetter.