GB156854A - Improvements in or relating to means for supplying fuel to internal combustion engines - Google Patents

Abstract

156,854. Neville, H. Sept. 2, 1919. Spray carburettors.-A carburettor in which the difference of pressure at two points of the engine intake is utilized to regulate the fuel valve automatically comprises a Venturi tube, a throttle valve, a diaphragm or piston, a fuel valve which tends to close and is adapted to be actuated by the diaphragm or piston, and ports or passages connecting both sides of the diaphragm or piston with chosen points in the Venturi tube, the arrangement being such that increase in the difference of pressure existing at the two points of the Venturi tube and due to the opening of the throttle valve causes an increase in the supply of fuel through the consequential opening of the fuel valve. As shown in Fig. 1, the intake pipe comprises a Venturi tube a open to the atmosphere at the end a<2> and provided at the throat with a fuel connection h and a fuel inlet valve b the stem of which rests on a diaphragm e. The chamber c above the diaphragm communicates with the throat of the Venturi tube through a port j, and the under side of the diaphragm communicates through a port k with another part of the Venturi tube, preferably near the throttle valve i and on the inner side thereof. The pressure on the underside of the diaphragm e may be regulated by air admitted through a valve l or through small ports in the cover d. An air valve may be provided in the wall of the chamber c to regulate the pressure above the diaphragm. Air may be supplied to the engine when the throttle is closed, through a port opening into the throat or other part of the Venturi tube, and controlled by a needle or other valve z, Fig. 5. The valve z may be operated independently, or may be operated by an arm w which is coupled to the throttleoperating lever v through a lost-motion device, so that continued movement of the lever v in the closing direction opens the valve z after the throttle is closed. Stops against which the arm wand the arm on the throttle valve abut may be provided to hold the valve z and throttle valve slightly open. In a modification, the throttle valve controls the outlet end of the Venturi tube, the fuel valve rests in a spindle projecting from the upper side of the diaphragm, and the port k is adjacent the end a<2> of the Venturi tube. In a further modification, which is preferably fitted vertically with the end a' of the Venturi tube uppermost, the inner side. of the diaphragm communicates through a valve-controlled port with the throat of the Venturi tube, and the fuel, controlled by a valve mounted directly on the outer side of the diaphragm, enters through the port k. In the form shown in Fig. 3, the fuel valve is carried by a piston e', the upper side of which is in communication through a passage o with the throat of the Venturi tube, and the under side of which communicates through a passage n and port k with another point in the Venturi tube. The passage n may be provided with an air inlet valve or port x<2>.