Abstract: A fitting is installed on the vent system of a carburetor to shield the last opening of the vent system from dynamic pressures caused by wind currents around this opening. This fitting in its simplest form is a plastic tubing "T", which is installed in the end of the vent tubing of the carburetor. It has been found that this fitting is effective in reducing the dynamic pressure effects on the carburetor internal reference pressure. It has also been found that a "T" having a larger diameter cross hole than perpendicular hole is more effective in reducing the dynamic pressure effects on carburetor reference pressure.

Abstract: An evaporative emissions control system for carburetors used in the internal combustion engines of vehicles, such as motorcycles, has an evaporative emissions control valve attached to the carburetor in the air intake path to the carburetor. The evaporative emissions control valve may be implemented as a sub-assembly add-on or as an integral part of a carburetor or back plate. The evaporative emissions control valve includes a valve, such as a rotatable plate valve, which may be electrically operated by an electrical actuator, such as a dual-wound solenoid actuator. At engine start-up, when the vehicle ignition switch and starter switch are both closed, both windings of the solenoid actuator are energized to provide a strong opening force for the evaporative emission control valve. During steady-state running of the engine, only a single solenoid winding is energized by the power provided through the ignition switch, to maintain the evaporative emissions control valve in the open position.

Abstract: An internal vent system contains a pressure sensing orifice located in a carburetor main bore or an auxiliary bore. In one embodiment, this orifice is moved thereby sensing different combinations of total and static pressure of the moving gas stream in which it is located. In another embodiment, the orifice is fixed with a moveable restrictor which changes the gas flow velocity across the orifice and thus changes the pressure sensed by the orifice. The pressure in this orifice establishes the average reference pressure for a float bowl carburetor or a wet diaphragm carburetor, and hence establishes the fuel flow through the carburetor. This adjustable vent is effective in changing fuel delivery over a wide range of engine operating conditions, and is able to minimize the need for changing high speed jets or mid-range calibrations due to changing atmospheric conditions or other operating parameters. The vent movement can be manual or automatic.

Abstract: An internal combustion engine having a carburetor including a float bowl that is internally vented through a venting path that extends from the carburetor bore to the headspace above the fuel in the bowl. An external bowl vent passageway extends through the carburetor body to permit air communication between the atmosphere external of the carburetor and the headspace. A thermally actuated valve is secured to a sheet metal cowling on the engine. A flexible tube is secured from the external vent passageway to the valve. While the engine is cold, the valve is open to permit the float bowl to be externally vented to the atmosphere, thereby providing a relatively rich fuel mixture which aids in starting the engine. Upon sustained engine operation and the attainment of a predetermined temperature, the valve closes the external vent passageway, thereby causing the float bowl to be internally vented only, thereby leaning out the fuel/air mixture to a desired emissions level during engine operation.

Abstract: A balance vent for an internally vented float fuel bowl type carburetor in order to dampen pulse signal fluctuation to the internal vent that is created upon an excess vacuum buildup in the float bowl. The balance vent is a restricted passageway that communicates at one end with the internal vent circuitry and at its opposite end with the atmosphere external of the carburetor. The balance vent is sized so that the vacuum in the fuel bowl is bled off to the atmosphere only to a certain extent to permit an overall bowl vacuum to remain so that the characteristics of the internal bowl vent are maintained.

Abstract: Method, system and apparatus for metering fuel to an internal combustion engine via a carburetor having a mixture conduit with a venturi therein. A main fuel nozzle supplies fuel to the venturi of the carburetor in response to the static pressure drop induced across an associated main fuel flow controlling restriction by the engine intake induced air flow through the carburetor mixture conduit. A pitot tube is disposed in the venturi with an opening facing upstream in a zone of maximum air flow through the carburetor venturi. A vent passageway system connects the pitot tube to a single closed air chamber cooperable with either a diaphragm or a float to regulate operation of an inlet valve controlling flow of fuel to a main fuel controlling restriction.

Abstract: In order to ensure correction for altitude for the carburetor used on a internal combustion engine, a control system for the pressure within the fuel bowl (8) is incorporated. This control system consists of a pressure splitter (11) that is connected, on the one hand, with the lower pressure of the venturi throat (4) in the area in which the fuel delivery line (7) opens out and, on the other hand, with the induction pressure in the area of the inlet end (10) of the air flow passage (4), said pressure splitter incorporating a pressure line (12) with two chokes (13, 14) that are connected in series, between which the fuel bowl (8) is connected to the pressure line (12). One or both of the two chokes (13, 14) can be controlled as a function of specific air density.

Abstract: A back draft carburetor of the type in which a vacuum source in the throat of a carburetor is communicated to the air space above the fuel in the float bowl of the carburetor includes a valve disposed between the vacuum source and the float bowl. At low vacuum levels in the carburetor throat, the valve is in a closed position in which the vacuum in the carburetor is sealed off from the float bowl. Upon sensing a higher vacuum level, the valve moves to an open position which allows the vacuum in the carburetor throat to be communicated to the air space in the float bowl.

Abstract: An inner air vent system for internal combustion engines is disclosed which prevents accidental flush of fuel from the float chamber into the venturi tube of the carburetor as when the vehicle is running on a steep slope or extremely rough surface. The inner air vent system comprises an air passage axially defined in the mounting bosses of the air cleaner, air intake pipe and carburetor, with the air cleaner being located above the carburetor. The air passage has a lower end thereof opened into the air gap inside the float chamber. With this arrangement, tilt of the vehicle even into an extreme position is unlikely to permit the flow of fuel from the float chamber into the carburetor venturi tube, because of the air passage having its upper opening held high enough above the fuel level in the float chamber. Furthermore, the inner air vent system can be constructed without the addition of extra joints and piping work, there is no significant increase in assembling cost.

Abstract: An engine auxiliary starting device installed in an outer vent control system of an automotive internal combustion engine for leading fuel evaporative gases from a float chamber to a canister. The auxiliary device includes an electromagnetic valve having an integrated circuit board which includes a sensor mechanism for detecting a predetermined temperature and a timer circuit for supplying an electric current to a solenoid coil for a predetermined time.

Abstract: An adaptor flange for fitting under the mounting flange of a carburetor of an internal combustion engine and formed with a venturi type flow passage having perforated induction tube spanning thereacross for sensing the magnitude of the partial vacuum in such passage. A controller housing is connected on one end with an air filter and is formed with an induction throat leading to a control chamber. Disposed in the induction throat is a nozzle which is, in turn, connected with the carburetor float chamber. Mounted in the control chamber are first and second pressure responsive valves. Such valves are connected through air/fuel vapor lines to the induction tubes and are responsive to predetermined engine conditions, as sensed in said flow passage, to cooperate therewith in selectively varying the flow rate through said induction throat to correspondingly vary the mixture to the intake manifold.

Abstract: Vapors normally arising within a standing gasoline tank are captured in a charcoal filled cannister. When the engine is running, air is drawn through the cannister thereby purging gasoline adsorbed on the charcoal within the cannister and delivering the purged gasoline vapors to the carburetor ultimately for combustion within the engine. Interference by the presence of such accumulated gasoline vapors in the carburetor, particularly during warm restarts and idling, can be avoided by preventing the injection of these gasoline vapors into the carburetor at the inappropriate times.

Abstract: A control valve device for use in a carburetor outer vent control system of an automotive internal combustion engine. The device includes a solenoid coil generating a magnetic force and a spring made of a shape memory alloy so that the device may control fluid communication in a fluid passage in response to an input current signal from a switch device and in response to changes in engine ambient temperature.

Abstract: A control valve device for use in a carburetor outer vent control system of an automotive internal combustion engine. The device includes a solenoid coil generating a magnetic force and a spring made of a shape memory alloy so that the device may control fluid communication in a fluid passage in response to an input current signal from a switch device and changes in ambient temperature.

Abstract: An intake system for an internal combustion engine having an air/fuel ration control device for closing the vent on a float chamber. The increased pressure within the float chamber from the incoming fuel enrichens the air/fuel mixture to the engine. The vent closure is effected by a valve controller responsive to intake vacuum. The controller is activated by vacuum experienced during engine braking. A bistarter choke system is disclosed including means for disabling the air/fuel ratio control device using either a switching apparatus or the higher pressures within the choke mechanism.

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 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 solenoid operated cut valve controls flow through a vent passage leading from a float chamber for a carburetor for an internal combustion engine. A normally closed switch opens in response to high temperature of the engine, and a normally closed timer switch opens at the start of cranking and closes again after a predetermined time of cranking. The switches are connected to the solenoid to prevent increase in pressure within the float chamber from delivering an excessive amount of fuel to the air intake passage of the engine. In a modification, a switch responsive to vacuum intensity in the intake passage is included in the solenoid circuit to facilitate acceleration of the engine after a hot start.

Abstract: An air valve type carburetor of the kind in which a throttle valve is disposed in the downstream portion of a barrel interconnected to an engine via an intake manifold; a main nozzle is disposed upstream of the barrel and is connected to a jet of a float chamber; an air horn disposed on the barrel is connected to an air cleaner via an air connector; an air valve is disposed at the upper part of the main nozzle, faces at its tip the nozzle and is connected to the base end of a metering needle which is inserted into a through-hole of the air horn for free vertical movement therein; and a shield plate is fixed to the shank of the metering needle so as to prevent pressure pulsations inside the air connector from entering the through-hole and being applied to the surface of the fuel.

Abstract: Disclosed herein is an outboard motor comprising a cylinder, a crankcase extending from the cylinder and including an upper portion having a bearing and a lower portion having a drainage outlet, a transfer passage extending between the cylinder and the crankcase, a drains return inlet in one of the cylinder and the transfer passage, a fuel supply system including an inlet manifold communicable with the cylinder and having a drains outlet and a carburetor communicating with the inlet manifold and having a drainage outlet, an overboard drain, and a valve and conduit system selectively operable for communicating the overboard drain with each of the manifold drains outlet, the crankcase drains outlet, and the carburetor drainage outlet, for communicating the crankcase bearing and the drains return inlet with the manifold drains outlet and the crankcase drains outlet, and for closing the carburetor drainage outlet.

Abstract: A carburetor fuel bowl vent valve assembly consists of a one-piece plastic housing having a central partition with a central well defining a zigzag shaped path for the flow of fuel vapors from the carburetor fuel bowl to a carbon canister. The well contains a vacuum operated vent valve that is spring opened during engine-off operation to allow the storage of fuel vapors under engine hot soak conditions, and is closed by engine manifold vacuum during engine running operation so that the fuel vapors will be rerouted into the engine. The vent valve further includes thermally responsive means to close the vent valve during low ambient temperature conditions. It also includes seal locating means that retain the seal in position without stretching or deforming it.

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 fuel return passage is provided between the fuel tank and the float chamber of a carburetor and arranged such that when the temperature of fuel upstream of the float chamber is higher than a predetermined value, the heated fuel in which vapor bubbles are contained is forcedly returned via the return passage to the fuel tank thereby preventing the carburetor from being supplied with such heated fuel.

Abstract: A carburetor float chamber venting system includes an intake system float chamber venting passage which leads from an upper part of the carburetor float chamber to the intake system, a fuel vapor absorption device float chamber venting passage which leads from an intermediate part of the intake system float chamber venting passage to a fuel vapor absorption device, and a control valve, provided at a part of the fuel vapor absorption device float chamber venting passage, whose operation controls the opening and closing of the fuel vapor absorption device float chamber venting passage.

Abstract: A vaporized fuel controller for a carburetor which utilizes the negative pressure in the intake manifold and electromagnet to actuate a changeover valve so as to connect the gas chamber of the float chamber to the inner vent when the engine is running, and to the canister when the engine is not running. With this invention, when the negative pressure in the intake manifold decreases while the engine is running at high speeds, the electromagnet keeps the valve from being moved by the spring force and maintains the valve at a position such that the vapor fuel is supplied to the intake manifold through the inner vent.

Abstract: An apparatus for use in conjunction with a conventionally carbureted internal combustion engine for improving fuel economy, which is connected to the carburetor float chamber and intake manifold of the engine and automatically lowers the fuel/air ratio during idle and other low-load engine operation by simultaneously reducing the pressure in the float chamber and allowing air to flow into the intake manifold.

Abstract: A vent changeover device for carburetors comprising two working ends provided on a piston rod of a piston moving in a suction chamber, one of which constitutes a rod end of the piston and the other of which constitutes an angle member joined to an end portion of the piston rod, an inner valve being actuated by the angle member so as to open and close an inner vent, an outer valve being actuated by the rod end so as to open and close an outer vent and disposed so as to face in a direction opposite to the direction in which the inner valve faces, and springs biasing the inner and outer valves, respectively, in vent-closing directions, the vents communicating with the fuel bowl via the respective valves, the inner and outer valves being adapted to be actuated in accordance with the movement of the piston rod such that when one of the valves is opened, the other is closed, the inner vent being opened only when the engine is rotated, and the outer vent being opened only when the engine is stopped.

Abstract: An overflow device for a vehicular carburetor. The carburetor includes a float chamber in which a maximum level is to be maintained. A drainage tube drains fuel at higher levels to a reservoir at an elevation lower than the carburetor. A vent tube vents the reservoir at an elevation higher than the carburetor. The reservoir can be heated by engine heat to evaporate excess fuel.

Abstract: A carburetor comprises an intake passage for supplying air and fuel, a venturi located in the intake passage, a nozzle opened in the venturi, a float member communicated with a fuel supply source and with the nozzle, an air vent for communicating the space above the liquid surface in the float chamber with the intake passage upstream of the venturi, and two communication conduits each of which has one end opened above the liquid surface in the float chamber and the other end opened at a suitable position in the intake passage in such a manner that a pressure difference is caused between the two communication conduits. One end of the first communication means is provided close to a fuel opening connected to the fuel supply source in the float chamber and the other end thereof receives higher pressure. One end of the second communication means is provided far from the fuel opening and the other end thereof receives lower pressure.

Abstract: A manually actuable primer for an internally vented float regulated fuel bowl type carburetor employs an arrangement for minimizing variations in fuel mixture richness resulting from variations in air intake path restrictions as might be created by a clogged air filter includes a bifurcated float bowl air vent conduit with one branch communicating with the carburetor bore in the region of the Venturi and the other branch communicating with the bore outside the region of the Venturi along with an arrangement for directing displaced fuel from the fuel supply chamber directly into a conduit which normally conveys fuel from a fuel well to the Venturi region, the directing arrangement being formed as an annular insert for the fuel well, the aperture of which forms the fixed fuel metering orifice of the carburetor.

Abstract: Apparatus for venting fuel vapors present in the fuel bowl of a carburetor for an internal combustion engine. A carburetor has at least one air passage through which air is drawn into the engine, a throttle valve positioned in the air passage and movable between an open and a closed position to control the flow of air therethrough, a fuel circuit by which fuel is delivered from the fuel bowl to the air passage for mixing with air passing therethrough, and means responsive to the movement of the throttle valve for controlling the quantity of fuel delivered through the fuel circuit. A fuel bowl cover has a vent through which fuel vapors discharge when the vent is open and a valve opens and closes the vent. A fuel pump supplies fuel from the fuel bowl to the air passage as the throttle valve opens and moves the valve to a vent opening position in response to the movement of the throttle valve. The pump is actuated as the throttle valve opens whereby the valve is opened and vapors in the fuel bowl are vented.

Abstract: A carburetor for internal combustion engines includes an inner vent passage through which the space on the free surface of liquid fuel in a float chamber is communicated with the intake passage of the carburetor and an outer vent passage through which the space in the float chamber is communicated with a charcoal canister adapted to store the fuel vapor coming from the space in the float chamber. A valve is movable between a first position in which the inner vent passage is closed and the outer vent passage is opened and a second position in which the inner vent passage is opened and the outer vent passage is closed. A pressure responsive valve actuator is operative in response to the vacuum in the intake passage to normally bias the valve to the first position and to move the valve to the second position when a vacuum is established in the intake passage. A further valve is diposed to control the connection and disconnection between the pressure responsive valve actuator and the intake passage.

Abstract: A gas carburettor suitable for mounting on a petrol carburettor of a combustion engine and intended for mixing a gas with air and for supplying the mixture of air and gas to the combustion engine. The gas carburettor comprises a housing having a centrally arranged passage bounded by a wall of the housing. The wall bounding the passage has an opening therethrough for supplying gas to the passage. A member is disposed in the passage such that an annular airway is defined between the housing and the member.

Abstract: A variable venturi type carburetor incorporating a changeover valve which conducts the fuel vapor in the float chamber either into the internal passage leading to the suction pipe of the carburetor or into the external passage leading to the canister. The changeover valve is actuated via a rod projecting into the intake passage by a suction piston which is displaced according to the amount of air drawn into the engine and which abuttingly contacts the rod. With this invention, an electromagnetic valve employed in the conventional carburetor can be obviated and the structure of the carburetor becomes simple and small.

Abstract: A carburetor improvement comprises a flow passage through which fuel vapors created in a fuel bowl are drawn off to a chamber having a first outlet through which fuel vapors are directed to a canister and a second outlet through which fuel vapors are directed to an air passage in the carburetor. A solenoid includes a valve member movable between a first position opening the first outlet and closing the second outlet and a second position closing the first outlet and opening the chamber outlet. The valve member is moved to its first position when the engine is off so fuel vapors are collected in the canister and to its second position when the engine is operating so fuel vapors are directed to the air passage.

Abstract: A carburetor for internal combustion engines includes an inner vent passage through which the space on the free surface of liquid fuel in a float chamber is communicated with the intake passage of the carburetor and an outer vent passage through which the space in the float chamber is communicated with a charcoal canister adapted to store the fuel vapor coming from the space of the float chamber. A valve is movable between a first position in which the inner vent passage is closed and the outer vent passage is opened and a second position in which the inner vent passage is opened and the outer vent passage is closed. A pressure responsive valve actuator normally holds the valve in the first position and moves the valve to the second position as a vacuum is generated in the intake passage. A further valve actuator holds the valve in the second position regardless of the action of the pressure-responsive valve actuator on the valve when the throttle valve has been opened to and beyond a predetermined opening.

Abstract: A starting mixture control for a carburetor that controls the richness of the fuel mixture being fed to an associated engine after initial starting, the carburetor having a throat for supplying air to the engine that is equipped with a choke valve upstream from a venturi constriction, a throttle valve downstream from the venturi constriction, a fuel bowl with a fuel nozzle opening into the throat at the venturi constriction, a bowl vent passage for providing atmospheric pressure to the fuel bowl during normal engine operation, and a pressure transmitting by-pass duct communicating between the bowl vent passage and the carburetor throat.

Abstract: An automatic control system for supplying a fuel-air mixture to an internal combustion engine through a Venturi structure conducting throttle-controlled incoming air to the intake manifold of the engine. Coaxially disposed in the casing of the structure is a cylindrical booster whose internal surface has a Venturi configuration to define a primary passage. Interposed between the booster and a ring having an external Venturi configuration mounted on the casing in an axially shiftable spool whose internal surface has a Venturi configuration to define a secondary passage having a variable throat between this surface and the spool. A tertiary passage is defined between the outer surface of the spool and the ring, incoming air passing through all three passages.

Abstract: A carburetor for internal combustion engines including an intake passage leading to a combustion chamber of the engine, a main fuel nozzle opening to the intake passage, a main throttle valve device provided in said intake passage, a float chamber for supplying fuel to said main fuel nozzle, a starting air passage opening to the intake passage at the downstream side of the throttle valve shut-off valve in the starting air passage, a second float chamber for supplying fuel to said starting air passage, and a passage introducing intake suction pressure to the upper portion of only the second float chamber. Also disclosed is apparatus wherein the main fuel nozzle and starting fuel nozzle communicate with a common float chamber, and the starter valve means comprises means for connecting the overlaying region of said float chamber with the intake passage downstream of the throttle valve when the starter valve means is in the open position.

Abstract: A carburetor has a float chamber and a device for adjusting the gaseous pressure in the float chamber. The device comprises a pressure source and a probe contacting the exhaust gas and delivering a signal which is a function of the exhaust gas composition. The device has an airflow pipe connecting the source to atmosphere, a throttle for impressing a head loss to the flow and controlled by the probe and a venturi located in the pipe and connected to the float chamber for giving a pressure which may be out of the range between the source pressure and atmospheric pressure.

Abstract: Apparatus for venting fuel vapors present in the fuel bowl of a carburetor for an internal combustion engine comprises a bowl vent through which fuel vapors discharge when the vent is open. A valve opens and closes the vent. A biasing force is exerted on the valve to close the vent. In response to starting of the engine first and second opening forces are exerted on the valve; these forces being sufficient to overcome the biasing force exerted thereon and open the vent. Each vent opening force is independently sufficient to open the vent and the vent is open when the engine is running even if one of the first and second forces is not exerted on the valve or is insufficient to open the valve.

Abstract: As part of an evaporative emission control system for an automotive vehicle, the fuel bowl of the carburetor for the internal combustion engine of the vehicle is provided with an internal vent passage for venting fuel vapor from the fuel bowl to the air cleaner, for example, for induction through the induction passage in the carburetor for flow to the engine during engine operation and, with an external vent passage for venting fuel vapor from the fuel bowl to a vapor storage canister when the engine is not in operation, as during hot soak, the internal vent passage having a cross sectional flow area at least two times larger than the minimum cross sectional flow area of the external vent passage whereby changes in pressure at the canister will tend to result in air cleaner depression changes with minimal differential pressures between the carburetor fuel bowl and air cleaner.

Abstract: Disclosed is a variable venturi type carburetor comprising a movable suction piston. The suction piston has a needle entering into a stationary jet. The needle and the jet defines an annular opening through which the fuel is injected into the intake passage formed in the carburetor. The jet is connected to a fuel reservoir via a fuel supply passage. The fuel reservoir is connected to the intake passage located downstream of the needle.

Abstract: A system and method for controlling a lean-burning internal combustion engine. The system and method enable a starter carburetor to operate at cold but not at hot temperature, to provide gulp air and counterbalance means for the starter carburetor, together with means to inhibit them at startup and for a brief time thereafter, and to inhibit exhaust gas recirculation when it would be deleterious to smooth operation. The system also provides for continuous accelerator pump operation during acceleration except at high temperatures. The objective is to secure smooth operation at startup, cold, warm or hot, and during transient conditions during engine warmup.

Abstract: A minute pressure control system which combines constant positive pressure and constant negative pressure together to control pressure in a controllable object is disclosed. An electronic control circuit generates a train of pulses modulated in accordance with a preset value. The two constant pressures, either one thereof being switched on and off in response to the pulses, are applied to a surge tank to be combined together therein. The surge tank absorbs pressure pulsation resulting from on-off switching application of the pressure and controls the pressure in the controllable object such as a half-closed chamber to the value preset by the electronic control circuit.

Abstract: A fuel supply system for internal combustion engines includes a fuel reservoir adjacent the induction manifold from which fuel is aspirated depending on pressure differences in two separate regions of the manifold.An electric controller reacts to engine rpm and exhaust gas composition signals to actuate electromagnetic valves in the air conduits leading from the manifold to the fuel reservoir. Various valve opening schedules can be performed depending on the desired fuel mixture.

Abstract: The carburetor fuel bowl has a vapor vent hole closed by a manifold vacuum opened valve to prevent fuel spillage during vehicle rollover. During engine operation with low vacuum, the accelerator pump mechanically inhibits closure of the vent valve.

Abstract: Vacuum, created by venturi effect of the throttle valve within the throat of a carburetor of a two cycle outboard motor, in company with a vacuum source orifice positioned opposite a peripheral edge of the throttle valve, is partially applied, by strategic placement of a vacuum source hole, to the fuel float chamber of the carburetor to reduce fuel flow over a selected range of engine RPM; normally when the boat it is driving is cruising on plane. A changeable vent to atmosphere is used to adjust the vacuum level to compensate for altitude changes and to adjust the carburetor to a particular motor. An expansion chamber in the vacuum source line may be required to prevent engine hesitation upon acceleration.

Abstract: An i.c. engine fuel system uses a conventional carburettor modified by the addition of an air pressure control to the float chamber thereof. The air pressure control includes a bank of valves connected in parallel to exhaust a chamber connected by an orifice to the engine intake manifold. The chamber is connected to the float chamber and the valves are controlled by the individual bits of a digital output signal produced by a digital read only memory addressed by digital signals corresponding to two engine parameters such as engine speed and throttle angle.

Abstract: A float bowl of an automotive engine carburetor is air-tightly covered by a diaphragm which is securely fixed to an electromagnetic transducer to be vibrated for controlling air pressure acting on the fuel being confined within the float bowl, whereby the amount of fuel delivered to the engine from the float bowl is controlled in dependence of the electrical signal applied.