Patent GB-1278317-A (GB)
Title: Improvements in or relating to carburetion systems
Inventor: COOK HARVEY ARTHER
IPC: F02M17/14
Filed: 1969-07-17
Abstract: 1278317 Spray carburetters; regulating TRW Inc 17 July 1969 36195/69 Heading F1B A carburation system comprises a throttle arm inter-connecting throttle valves in individual supply pipes 13a-13d, Fig.2, from a manifold, 12 Fig.3, air-fuel mixture conduits connected between a primary air chamber 56, Fig.3, and the supply pipes downstream of the throttle valves, air metering means 40 communicating with the manifold and responsive to the flow-rate therein for urging a fuel metering means 64a into an increasingly open position to a limit set by an adjustable limiting means 80 and automatic throttle control means 21, Fig.5, operatively connected to the throttle arm to maintain the manifold vacuum constant. The system 10 has an intake air manifold 12, Fig.2, connected to intake ports A..D through pipes 13a..13d including throttle valves 14a..14d which are actuated through a linkage by an automatic actuator 21. The latter has a piston 97, Fig. 5 acted on by the manifold vacuum in chamber 94 and in chamber 91 a vacuum transmitted by a vacuum controller 120, Fig.4, which may be either the manifold vacuum or the vacuum downstream of the throttle valves i.e. the after-throttle vacuum. At a desired manifold vacuum level, e.g. 5"Hg, the plunger 136 of the vacuum controller is in the Fig.4 position. A drop in manifold vacuum level causes downward movement of plunger 136 to communicate bore 144 (and afterthrottle vacuum) with bore 127, conduit 117 and chamber 91. This causes the piston 97 to move to the right in Fig. 5 to open throttle valves 14a.. 14d, Fig.2. An increase in manifold vacuum causes closure of the throttle valves 14a.. 14d. Operation of carburation system: Pedal 89, Fig.3 controls the setting of a piston 80 of the air-fuel distributor 24 which has an air metering element 40 and a fuel metering rod 64 linked for conjoint movement. Air flowing into the air intake manifold 12 acts on the air metering element 40 moving the assembly to the left until stopped by the wall 81 of the piston 80. Starting and idling: When the engine is cranked the fuel pump 60, Fig.3 supplies fuel through a pressure regulator 61 to inlet port 53 and the increase in air intake manifold vacuum causes closure of the throttle valves 14a-14d are previously described. Movement of the stop 81 to an idling position allows fuel to flow from fuel chamber 54 through passage 57 into a primary air chamber 56 where it is mixed with primary air passing through inlets 35, passages 32, chamber 30, further passages 32, and passages 38, 75 and 72. The mixture passes through bores 77 and conduits 78 to the supply pipes downstream of the throttle valves 14a..14d. The air intake manifold vacuum causes the air metering element 40 to take up a position in which the coil spring force balances the vacuum effect. Acceleration and Power: Actuation of pedal 87 allows the air and fuel metering elements 40 and 64 to move leftwardly and the leftwards movement of the flange 44 across bores 32 increases the air metering area and causes a reduction in the air intake manifold vacuum which results in the opening of the throttle valves 14a-14d. Deceleration and fuel cut-off: Raising of pedal 89 causes movement of stop 81 to the right together with air and fuel metering elements 40, 64 thereby lowering of the flow-rate of secondary air into the manifold 12 and lowering the flow-rate of primary air into the primary air chamber 56. The increase in manifold vacuum results in the closing of the throttle valves 14a-14d. The shape of the fuel metering element 64 prevents the flow of liquid fuel through passage 57 during shutdown periods. In a modification a parallel, grooved metering element 64' is substituted for the fuel metering element 64.