GB731892A - Improvements in carburetting systems for internal combustion engines - Google Patents

Abstract

731,892. Spray carburetters ; auxiliary air admission. SOLEX. July 22, 1953 [July 23, 1952], No. 20379/53. Classes 7(2) and 7(3). A device for temporarily reducing the richness of the mixture supplied by a carburetter, particularly when the engine is being restarted whilst hot, is brought into and out of action by a thermo-sensitive device constituted by a bimetallic disc-shaped element 9 having approximately the shape of a portion of a sphere. the concavity of which element changes in direction at a temperature which is higher when the temperature to which it is subjected is rising than when this temperature is dropping. In Figs. 3-5 extra air is admitted to the carburetter, or, as shown, to the induction pipe through a flange member 7 having a passage 10 normally closed by the bi-metallic element 9 arranged adjacent the exhaust manifold 6, the extra air being supplied from the carburetter intake pipe through a passage 16. During normal running the flow of cooling air maintains the element 9 cool and in the position shown in Fig. 3 closing the passage 10. When the engine is stopped the temperature of the exhaust manifold 6 and associated engine parts rises rapidly and at a temperature of about 80‹C. the curvature of the element 9 suddenly reverses, as shown in Fig. 4, whereby the passage 10 is connected through the passages 14 to the extra air supply passage 16 the air supply through which is preferably filtered by the carburetter filter 5. The element 9 remains in its inverted position for a considerable time, e.g. for twenty to thirty minutes, until the engine temperature has dropped to about 40‹C., so that if the engine is restarted during this period extra air enters through the passage 10 and dilutes the rich mixture which is formed in the intake manifold by fuel expelled from the carburetter nozzles by the rise in engine temperature when it is stopped. The flow of extra air past the element 9 quickly reduces its temperature so that a few seconds after restarting, its curvature is again reversed and the passage 10 is closed. A light spring 13 prevents small pressure fluctuations in the intake pipe forcing the valve off its seat. In a modification the curved element 9 is connected to a valve member which controls the passage 10 and in a further embodiment the element 9 reduces the fuel supply from the fuel jet system if the engine is started whilst hot.