GB732342A - Improvements in or relating to carburettors for internal combustion engines - Google Patents

Abstract

732,342. Carburetters. MORGENROTH, H. Sept. 13, 1950 [Sept. 13, 1949] No. 22511/50. Class 7(3). In a carburetter comprising means defining an air passage, an air control valve in the air passage, a venturi or similar constriction for producing a low pressure region in the air passage downstream of the air control valve, at least one rich mixture producing carburetter delivering substantially its entire mixture into the low pressure region, the rich mixture producing carburetter comprising means defining a carburetter passage, a mixture producing stage in the carburetter passage, a fuel jet at the mixture producing stage and a throttle valve in the carburetter passage and means operatively connecting the air control valve and throttle valve for associated movement, the throttle valve comprises a movable apertured plate valve operatively associated with the carburetter passage providing a variable effective opening. In Fig. 3 rich mixture is formed in passages 67, 66 brought into operation alternately by means of a slotted plate valve 62 controlled conjointly with an air control valve 78. The idling arrangement comprises a passage 76 and adjustable needle valve 77. A simpler form of Fig. 3 is described in which there is one rich mixture passage only and the axis of the venturi is vertically disposed. The idling arrangement comprises an air inlet controlled by a thumb screw and a separate fuel nozzle. In Fig. 5 a slotted plate valve 91 controls the main air inlet 84 and an idling passage 89 and rich mixture passage 88. Figs. 6 and 7 show a further embodiment comprising a notched plate 108 which controls a main air inlet 102, and rich mixture passages 103, 104. An idling passage 105 is provided. The passage 104 includes an adjustable restriction 117 which is preferably controlled by the operator. When the valve 108 is rotated fully to the left all the passages except the passage 105 are closed. During idling fuel is drawn through the transverse passage 118 and mixed with air in the passage 105. For low load operation passage 109 is opened while for higher engine loads the rich mixture passage 111a is opened and at the same time air is permitted to flow through the passage 111. It is stated that the so called low load rich mixture carburetters may operate up to 70 per cent of the load. The restrictions in the idle and slow speed passages need not be venturis. Usual compensating mechanisms may be incorporated. The plate valve need not turn about an axis but could have a rectilinear motion. An additional valve could be provided anterior to the fuel jet or air control valve. The air and mixture control valves may be connected by compensating connections which may compensate for altitude and temperature changes &c. The carburetter may be supplied with air under pressure instead of drawing it from the atmosphere. There could be more than two rich mixture carburetters with a corresponding number of gate apertures.