GB471508A - Improvements in carburetters for internal combustion engines - Google Patents

Abstract

471,508. Spray carburetters. SOC. GENERALE DES CARBURATEURS ZENITH. Dec. 4, 1935, No. 33643. Convention date, Dec. 5, 1934. [Class 7 (iii)] In a carburetter in which fuel is supplied by a pressure regulator to an outlet opening into the induction passage on the engine side of the throttle, the fuel output controlled by the pressure difference between the regulator and the induction passage is subject to a superimposed control from a regulating member connected with a movable wall separating two chambers, one of which is connected with the induction passage behind the throttle valve, preferably in the vicinity of the fuel outlet, whereas the pressure in the other chamber is unaffected by the pressure in the induction passage or in the atmosphere. The position of the movable regulating member which varies the amount of fuel supplied by the fuel outlet depends on the absolute pressure in the mixing chamber and this member modifies the fall of pressure under which the fuel is delivered substantially in proportional relation to the absolute pressure. The pressure at which fuel is supplied to a nozzle 7, Fig. 1, from a chamber 10 of a diaphragm type regulator 9 is varied by a valve 23 in the dry chamber 15 which is open to the atmosphere or air inlet through a calibrated orifice 16, the valve being operated by a bellows 22, in a chamber 18 communicating with the mixing chamber 1 above the throttle valve 4, which also controls a valve 8 in the nozzle 7. The chamber 15 may be the space above the fuel in a float chamber. When it is desired to emulsify the fuel, the dry side of the diaphragm is at the same pressure as the air inlet and the fuel needle valve 48, Fig. 3, controls an inlet into an intermediate chamber 50, the pressure in which is determined by the size of an air inlet 52 controlled by a valve 54 connected to the suction operated expansible chamber 55, the emulsified fuel entering the mixing chamber 1 through a calibrated passage 51 around the stem of the needle valve 48. In a modification, the chamber 50 communicates directly with a second chamber in which the variable pressure is produced. In other modifications, the expansible chamber controls the fuel valve, the throttle actuates a control valve for the variable pressure, and the expansible chamber controls the fuel valve, varying its cross-section according to the square root of the absolute pressure in the mixing chamber. In the form shown in Fig. 5, a tapered fuel outlet 80 is controlled from one end by a sleeve 70 linked to the throttle control and at the pointed end by a sleeve 86 operated by the expansible chamber 90. According to the Specification as open to inspection under Sect. 91, a piston may replace the diaphragm. This subject-matter does not appear in the Specification as accepted.