GB749552A - An improved carburettor for internal combustion engines - Google Patents

Abstract

749,552. Carburetters. MASSAROTTI, M. Nov. 20, 1953 [Dec. 1, 1952], No. 32281/53. Class 7(3) In a carburetter having a suction conduit open at one end to atmosphere and at the other end to a throttle passage and a liquid fuel outlet nozzle disposed in the suction conduit the inlet and outlet ends of the suction conduit are of greater diameter than the central portion of the conduit and the nozzle is located within the central minimum diameter portion facing the inlet end of the conduit, the rate of flow of fuel through the nozzle being determined by a valve which is under the control of a deformable diaphragm subjected to the depression created in the suction conduit by the engine. As shown there are two inlet passages 1 intended to be fitted with an air filter not shown and four conduits 2 (two only of which are shown), and each leadings to a cylinder of the engine. Fuel from a pump (not shown), e.g. of diaphram type enters by way of a passage 9 and flows past a valve 10 to passages 7. Each passage 7 leads by way of an external conduit 6 to a passage 5 associated with two fuel nozzles 4. The valve 10 is controlled by engine suction which acts on the underside of a diaphram 14. A suction operated valve 36 (see also Fig. 3), controls the supply of fuel for idling. The valve co-operates with two seats and .in its right hand position prevents flow of fuel from a passage 38 into a chamber 37 and in its left hand position cuts off communication between the chamber 37 and a space 32. Thus at normal engine speed a spring 39 holds the valve in its left hand position but when the throttle valves 25 are in their idling position the high suction acts to hold the valve in an intermediate position so that idling fuel can flow from the passage 38 past the valve to the space 32 and - from there to idling fuel delivery passages 29. During high speed operation with the throttle valves in the idle running position the suction is sufficiently high to move the valve to the right to shut off the passage 38 from the chamber 37. The load of the valve spring 39 is preferably adjustable. The fuel flow through the conduit 38 may be regulated by means of a valve (not shown). A restricted. passage 35 or a check valve is provided between the space beneath the diaphram' 14 and the space 32. A substantially rectilinear fuel spirit is obtained.