Abstract: An arrangement for limiting the temperature in a carburetor etc. of an engine prevents evaporation of fuel at a temporary stop in the operation of the engine. A receptacle (30) integrated with the carburetor contains a material (31), e.g. paraffin, with a melting point over the normal operating temperature. At a temperature above this melting point the material absorbs melting heat from the environment causing a limitation of the temperature. In this limited temperature the fuel evaporates much slower and a direct start with the remaining fuel after the operating stop is quite possible.

Abstract: A fuel supply device for an internal combustion engine comprises a constant level chamber (typically a float chamber) formed in a casing which may be the body of the carburetor of the device. A heat exchanger is formed in the casing or in contact with the casing. A cooling liquid is circulated in a closed-loop circuit including the heat exchanger and a liquid reservoir having a large volume as compared with that of the balance of the circuit.

Abstract: A vapor return primer for priming and regulating pressure in a carburetor is disclosed. The vapor return primer includes a housing having an inlet and an outlet. The inlet is coupled with the high pressure side of the carburetor. The outlet is coupled with a fuel tank. A resilient flexible membrane is coupled with the housing for moving fluid through the inlet and outlet to prime the carburetor. A pressure relief mechanism is coupled with the housing to provide one-way flow from the housing through the outlet to the fuel tank during priming. Also, the pressure refief mechanism regulates the carburetor pressure when the internal combustion engine is in a continuous running mode.

Abstract: A diaphragm carburetor with a fuel metering chamber designed for easy restart when hot which includes a separate escape chamber connected to the metering chamber having a second diaphragm controlled exhaust valve. The second diaphragm is subject to positive crankcase pressure during engine operation to maintain the exhaust valve closed. When the engine is stopped, the exhaust valve is opened by a spring and fuel in the metering chamber will move into the escape chamber and out of the carburetor rather than be forced into the fuel mixing passage and venturi of the carburetor. A porous absorbent material is positioned to receive the fuel leaving the open exhaust valve and to retain it until it vaporizes and dissipates through openings in the retainer atmosphere. The exhaust valve may be manually operated as an option.

Abstract: A diaphragm carburetor with a fuel metering chamber designed for easy restart when hot which includes a separate escape chamber connected to the metering chamber having a second diaphragm controlled exhaust valve. The second diaphragm is subject to positive crankcase pressure during engine operation to maintain the exhaust valve closed. When the engine is stopped, the exhaust valve is opened by a spring and fuel in the metering chamber will move into the escape chamber and out of the carburetor rather than be forced into the fuel mixing passage and venturi of the carburetor.

Abstract: A diaphragm carburetor for small internal combustion engines of generally standard construction but improved features for facilitating hot starting due to engine heat or environmental heat which transmits to the carburetor. An automatic or manual relief passage from the diaphragm chamber relieves pressure on fuel due to heat conductors so that a rich fuel charge will not be forced into the engine but will release to atmosphere, thus permitting a normal fuel mixture to be directed to the fuel mixing passage upon a restart of the engine.

Abstract: The device for mounting a carburetor having a body made of synthetic resin comprises a heat insulating member for intercepting transmission of heat from a cylinder of an engine to the carburetor and a temperature adjusting metallic member is interposed between the heat insulating member and the carburetor.

Abstract: A carburetor with an idling system is designed so that the full pressure differential or gradient available between approximately ambient pressure and the vacuum in the intake tube is employed for producing a critical pressure ratio of a supersonic flow in a laval nozzle. To make this possible, a fuel air emulsion formed with primary air is introduced from a mixing duct via a constricted orifice of a tubular nozzle at a bore constriction, at which there is always a sonic velocity when there is a critical and supercritical pressure ratio, into the secondary air flow where it is superfinely atomized in the secondary air flow, with a maximum velocity differential, aided by subsequent pressure surges.

Abstract: The invention discloses a carburetor percolation prevention system which utilizes an electrically controlled fuel drain valve disposed in a fuel drain passage between the carburetor float chamber and the fuel tank. The electrical fuel drain valve is opened only when the engine condition sensor and the temperature sensor indicate that both the ignition switch is de-energized and the temperature near the float chamber exceeds a predetermined level.

Abstract: A diaphragm carburetor provided with a temperature-sensitive lever arm is disclosed. The temperature-sensitive lever arm permits hot restart of an engine when the carburetor is in a vapor lock condition, without the use of the choke mechanism.

Abstract: In a variable venturi type carburetor having a slow speed system, a fuel vapor conduit is provided, an inlet of which is open to a main fuel passage, an outlet of which is open to an intake passage. Fuel vapor occurring in the main fuel passage is carried through the fuel vapor conduit, so as not to be introduced into a slow fuel passage; thereby, the engine is rotated stably with a relatively lean air-fuel ratio.

Abstract: A system for controlling a carburetor of an engine provided with a supercharger. A passage is provided for communicating a float chamber of the carburetor with an intake passage through a changeover valve. A vent pipe is provided for communicating the float chamber with the intake passage. The changeover valve comprises a diaphragm, a vacuum operated chamber defined by the diaphragm, a valve body operatively connected to the diaphragm, a passage for communicating the vacuum operated chamber with the intake passage at the downstream side of the carburetor, an opening for communicating the float chamber with the intake passage, and an opening for communicating the float chamber with the atmosphere. The vacuum operated chamber and the valve body are so arranged that the valve body closes the first opening and opens the second opening at light load to communicate the float chamber with the atmosphere.

Abstract: A carburetor includes a pendulum metering element delivering fuel to a hollow throttle shaft from a fuel metering chamber by means of a graduated depth groove in the chamber wall which is engaged by a spring urged jet member carried by the pendulum element and offering constant fluid-tight engagement with the chamber groove with minimum frictional drag. Stability of both fuel metering/vaporization throughout variations in temperature is significantly enhanced by formation of the carburetor body from a machined block of a metal selected for its ideal combined capability of heat storage and dissipation. An improved sealing assembly between a float and fuel chamber and the metering chamber coupled with a regulator device insuring a constant fuel inlet pressure enhances this stability of operation.

Abstract: In a variable venturi type carburetor having a slow speed system, a fuel vapor conduit is provided, an inlet of which is open to a main fuel passage, an outlet of which is open to an intake passage. Fuel vapor occurring in the main fuel passage is carried through the fuel vapor conduit, so as not to be introduced into a slow fuel passage; thereby, the engine is rotated stably with a relatively lean air-fuel ratio.

Abstract: A system preventing the percolation of fuel in a carburetor comprising a first passage communicating a space of a float chamber of the carburetor with the atmosphere, a diaphragm valve with a vacuum chamber for closing the passage, and an inner vent pipe for communicating the space of the float chamber with an intake passage of the carburetor. A thermo sensor is provided for sensing the temperature of the carburetor and for producing a signal when the temperature reaches a high temperature which would cause the percolation of the fuel. The diaphragm valve is operated in dependency on the signal of the thermo sensor to open the passage to communicate the space of the float chamber with the atmosphere.

Abstract: A system for preventing percolation of fuel in a carburetor for a motor vehicle. The system is provided with air passages for communicating a float chamber of the carburetor to the air and to a canister filled with charcoal particles. Valves are provided in the passages for opening the passages, when the engine operation is stopped and the temperature of the fuel in the float chamber is high. A fan is provided for introducing the air into the float chamber and for discharging the air to the canister together with vapor of the fuel in the float chamber, thereby to promote the evaporation of the fuel to cool the fuel by the evaporative cooling.

Abstract: A variable venturi carburetor including a fuel bypass duct bypassing the fuel metering portion of the fuel jet, the fuel jet being provided with an opening at its upper portion which opening is in opposed relation with the inlet of the fuel bypass duct for easily delivering fuel bubbles created in the fuel jet and also provided with a fuel inlet at its lower portion which is so constructed as for fuel to readily flow into the fuel jet.

Abstract: Disclosed herein is an improvement in a variable venturi carburetor for an internal combustion engine which comprises a venturi portion, a float chamber, a main fuel passage communicating with the venturi portion and with the float chamber, a main fuel jet provided in the main fuel passage and a movable metering needle. A free end of the metering needle is adapted to control the size of the main fuel jet and the base portion of the metering needle is mounted to a suction piston adapted to transversely move with respect to the venturi portion in response to the condition of load on the internal combustion engine. The improvement includes provision of a bypass detouring upwardly from a portion of the main fuel passage upstream of the main fuel jet for discharging vapor of fuel, and the bypass communicates with a negative pressure passage which has an opening in the lower portion of the venturi portion and with an air passage which has an opening in the vicinity of an air horn inlet.

Abstract: In a constant-pressure carburetor having a fuel/air mixing chamber (3) which operates under reduced pressure, fuel feed means through which the fuel is drawn into the mixing chamber (3) from a float chamber (6) as required, an air inlet duct (1) having an automatically vacuum controlled air intake valve (2) upstream of the mixing chamber (3), and a suction duct having a driver actuated throttle member (4) downstream of the mixing chamber (3), the fuel feed means includes a fuel atomizer nozzle (5) having a central fuel supply passage (14) surrounded concentrically at its outer end by an annular constricting atomizing air outlet (15) whereby the velocity vectors of fuel and atomizing air at the nozzle outlet differ in magnitude and direction, and proportioning means for regulating the flow of fuel through the central passage (14) of the nozzle (5) and including a member (11) which is movable towards and away from the inlet (10) to the passage (14) by a control (12) operated in response to the output (A) from a

Abstract: An improved carburetor (20) for delivering one combustible fuel and a liquid, or two combustible fuels from separate reservoirs (50), (500), to the central portion of a hollow spray bar (98) for discharge into carburetor venturi (30) includes substantially closed metering chambers (90), (508) disposed in fuel flow communication from the reservoirs and suspended from opposite ends of spray bar (98). Fuels from metering chambers (90), (500) travel through variable width grooves (154), (548) formed in arcuate metering inserts (148), (544) into the lower end portion of corresponding metering arms (92), (540) and then into the hollow interior of spray bar (98).