Patent GB-772438-A (GB)
Title: Improvements relating to carburation systems
IPC: F02M9/133
Filed: 1953-06-16
Abstract: 772,438. Carburetters. GRILLET, L. Sept. 16, 1954 [June 16, 1953; April 13, 1954], Nos. 16582/53 and 10877/54. Class 7 (3). A carburetter system comprises a passage distinct from the main induction system through which a mixture of fuel and air is passed and which leads into the main induction system near the engine the form of passage being such that the mixture which passes through the passage on emerging into the main induction system is cooler and at a higher pressure than the mixture which passes through the main induction system. In Figs. 1 and 2 a downdraught carburetter has a main fuel jet 23 with orifices 24 concentric with the carburetter body in a tube 26 around which is an annular space 27. The tube leads to a part 33 from which pipes 58,59 lead to induction pipes 65,66 downstream of the throttle valve 45. The engine inlet valves are indicated at 721, 72<SP>2</SP>, 72<SP>3</SP> and 72<SP>4</SP>. Valve 40 is controlled conjointly with the engine throttle valve 46. Additional air is admitted although an orifice 50. A slow running passage 51 terminates in a pot 53 downstream of the valve member 40. The sleeve 28 rises and falls in accordance with the rate of flow of mixture. There is a small hole 41 in the valve member 40 which ensures flow of mixture in the by-pass passages even if the throttle valve is closed. A small pipe 25 leads to an accelerating pump. In Figs. 4-6 a trough 141 is located in the induction pipe and is connected by way of a rotary sleeve valve 157 to pipes 171,172 additional air is admitted at 161,162 under control of a piston valve 312 operated by suction. The passage 137 is opened before the inlets 161,162. The sleeve valve is controlled conjointly with the throttle valve. In the closed position a small opening is left between the bore 137 and the passage 151. Further control valves 85,86 are provided. The trough 141 may be replaced by a member resembling the bowl of a tobacco pipe. Figs. 11-13 show another embodiment comprising a rotary sleeve valve 195. Additional air is admitted through inlets 202,203. A bore 192 leads from a normal slow running feed passage 193. In summer the needle valve 207 is closed so that the slow running mixture is fed solely through the by-pass passages. In winter the needle valve 206 is closed so that the slow running mixture is fed through the usual inlet manifold. In Fig. 14 a tube 352 has an opening 353 directed towards the carburetter choke tube 351. Within the tube there is a sleeve 357 having an opening 353 cooperating with the opening 358. Ports 359,360 cooperate with air inlets 361,362. It is stated that the mixture may be drawn through the by-pass passages by the engine suction or a supercharger may be provided for example one driven electrically and brought into operation when the engine exceeds a predetermined speed. Preferably the points of each sparking plug lie substantially at the centre of the clearance space when the piston is in its upper position. The fuel admitted to a cylinder may be approximately equally divided between the two mixtures supplied. Vaporisation of the fuel in the main stream of mixture may be brought about by heating for example by contact between the intake manifold and the exhaust manifold. In each embodiment a carburetter and an inlet manifold of existing type are modified.