Abstract: A fluid metering pump (1) is disclosed which is operated by a source of pressurised fluid, which in the case of a pump for metering fuel, may be the crankcase (37) of a two stroke, crankcase scavenged, internal combustion engine. The metered quantity of fluid displaced by the pump (1) is a function of the pressure of the pressurised fluid and time that the pressure acts on a pumping means (15) of the pump (1). Attenuation of the pressure may be achieved, especially under idle or high engine speed conditions in the case of an engine, by a throttle (35) placed in a conduit (33) communicating an actuation chamber of the pump (1) with the source of pressurised fluid, such as the crankcase of a two stroke engine.

Abstract: A method and device for increasing the amount of fuel to an engine during acceleration is provided. A secondary source of fuel in addition to a first source of fuel is introduced into the engine during acceleration. The secondary source of fuel is introduced through a secondary fuel delivery line which is opened by a valve actuated in response to throttle control movement. In a first embodiment, the secondary fuel delivery line communicates with a fuel delivery area from which fuel is supplied to the first fuel source. The valve is pressed open by the throttle control along with a primary fuel source needle valve control, allowing fuel from the fuel delivery area to flow through the second fuel line in addition to the first fuel source. In second and third embodiments, the secondary fuel line communicates with an excess fuel return line. A valve extends across the fuel return line and secondary fuel line.

Abstract: A diaphragm type carburetor is disclosed wherein a cantilever portion is used to augment the resilience of a first diaphragm and return it to an undeformed position during the neutral signal produced by a 4-cycle engine. The cantilever portion cooperates with the intermittent vacuum signal from the crankcase piped to one side of the first diaphragm so as to oscillate the diaphragm and draw fuel from the fuel tank of the engine into the carburetor. The device is also suited for use with 2-cycle engines which produce both vacuum and pressure pulses wherein the cantilever portion is used to augment either pulse to improve the performance of the fuel diaphragm.

Abstract: Fuel to which a predetermined pressure is applied is supplied to an electronically controlled fuel injection system of a engine for models in order to improve the rotation stability during low speed operation and the response to rapid acceleration or deceleration.The pulsatory air pressure is generated in a crank chamber of a engine for models during operation. An air pressure intake guide 51 of a fuel pressure control valve 1 receives air pressure from the crank chamber. The air intake guide is provided with an excessive pressure leak valve the actuation pressure of which is adjustable. The air pressure intake guide communicates with interposition of a check valve 56 to a controlled air pressure supply passage 54 which communicates to a fuel tank. The check valve 56 supplies the positive pressure of the pulsatory air pressure from the controlled air pressure supply passage to the internal of the fuel tank.

Abstract: A carburetor start pump circuit, for starting an engine, has an auxiliary fuel pump mounted on a relatively standard carburetor body, a pulse passageway extending through the carburetor body to the auxiliary fuel pump, and a fuel circuit having an intake side extending from a metering chamber in the carburetor body to the auxiliary pump where it is interconnected to a discharge side extending from the auxiliary pump to a throttle bore in the air intake of the carburetor body. To facilitate control of fuel flow, the fuel circuit includes inlet and discharge check valves and a metering jet.

Abstract: A crankcase fuel injection system includes a diaphragm type fuel pump, a crankcase fuel injector assembly, and a main air inlet assembly. Engine crankcase pulses generated by the up and down movements of the piston are utilized by the fuel pump to replenish the fuel mixture in a fuel mixture injector chamber of the fuel injector assembly. The air mass entering the crankcase upon the upstroke of the piston is controlled within the main air inlet assembly by a throttle valve and metered across a main air venturi. The venturi signal at the main air venturi is amplified by a booster venturi. The amplified venturi signal is applied to a middle chamber formed between the two diaphragms of the compound diaphragm assembly which serves as the injector pump mechanism. The force acting upon the diaphragm assembly due to the amplified venturi signal is further amplified due to the area relationships of the two diaphragms.

Abstract: A closed loop fuel supply system for operating engines in all possible attitudes in which fuel is delivered by a vacuum pump responsive to the vacuum level in the crankcase of the engine and in which the vacuum driving the pump is modulated in response to the pressure of fuel being delivered to the fuel supply system so that the amount of fuel delivered for combustion purposes is equal to the requirements of the engine without any excess. In another embodiment, the delivery of pulsating fuel is dampened to obtain a uniform fuel delivery and distribution to the combustion chamber is under the control of three shutoff valves operating throughout the speed range of the engine. In each embodiment fuel is conserved and a fuel return line is not required.

Abstract: The invention is directed to a fuel-injection arrangement for a two-stroke engine in a portable handheld work apparatus such as a motor-driven chain saw or the like. Fuel is drawn by suction from a fuel tank by a fuel-feed pump and is made available at the suction connection of an injection pump. The injection pump has a pressure connection which is connected to an injection line through which the engine is supplied with fuel. A rapid start of a two-stroke engine provided with this fuel-injection arrangement is achieved by providing a bypass line which conducts fuel and bypasses the injection pump. A switchable flow valve is mounted in the bypass line. The bypass line opens directly into the intake channel conducting combustion air to the engine so that even without the pump action of the injection pump, adequate fuel is made available to the engine for starting the same.

Abstract: The invention is directed to a fuel-injection arrangement for a two-stroke engine in a motor-driven chain saw. An injection pump is mounted in a base housing with the injection pump including a pump piston axially displaceable in a pump cylinder. The pump piston delimits a pump chamber. The pump chamber is connected via a suction valve to a fuel tank. The fuel drawn by suction is pumped by the pump piston via a pressure valve, an injection line and an injection valve to the engine. For driving the pump piston, the latter is connected at one end to a membrane via a membrane plate. The membrane delimits a work chamber charged with fluctuating crankcase pressure. A simple assembly is provided by arranging the pump chamber, the suction valve and the pressure valve in a common valve housing which, in turn, is seated in the base housing of the injection pump in a seal-tight manner. The injection line is connected directly to the valve housing.

Abstract: A closed loop fuel supply system for operating engines in all possible attitudes in which fuel is delivered by a vacuum pump responsive to the vacuum level in the crank case of the engine and in which the vacuum driving the pump is modulated in response to the pressure of fuel being delivered to the fuel supply system so that the amount of fuel delivered for combustion purposes is equal to the requirements of the engine without any excess so that a fuel return line is not required.

Abstract: A fuel-injection arrangement and a two-stroke engine define a combination for a portable handheld work apparatus such as a motor-driven chain saw or the like. The combination includes a fuel-feed pump for pumping fuel from a fuel tank and a fuel-injection pump for supplying the fuel for injection into the engine. The fuel-feed pump and the fuel-injection pump are mounted in a con, non injection-pump block separate from the engine. The engine has an intake channel through which combustion air is drawn into the engine and the intake channel is configured so as to open directly into the engine. A throttle flap is pivotally mounted in the intake channel as to be completely separate from the common injection-pump block. The injection pump block is effectively thermally decoupled from the intake channel. The danger of vapor bubble formation because of a heating of the injection pump is thereby reliably avoided.

Abstract: A digital fuel control system for a small internal combustion engine having a pressure sensor for detecting the instantaneous pressure in the air intake manifold of the engine to generate air pressure data. A microprocessor responsive to the air pressure data generates a fuel quantity output signal indicative of the quantity of fuel to be delivered to the engine. A fuel metering apparatus responsive to the fuel quantity output signal generated by the microprocessor meters the fuel being delivered to a fuel delivery mechanism which delivers the fuel into the air intake manifold of the engine. The microprocessor in response to the air pressure data generated by the pressure sensor determines the engine's speed and the average pressure of the air inhaled by the engine. The engine speed data and air pressure data address a look-up table to extract data indicative of the fuel requirements of the engine.

Abstract: Disclosed herein is an engine comprising an engine block, a crankcase cover mounted on the engine block and including opposite first and second sides, a first carburetor mounted on the block at the first side of the crankcase cover, a second carburetor mounted on the block at the second side of the crankcase cover, a bracket supported by the crankcase cover intermediate the first and second carburetors, and a fuel supply component mounted on the bracket and comprising one of a fuel pump, an oil pump, a combined fuel and oil pump, a fuel vapor separator, a fuel vapor pump, a fuel filter, a primer fuel control valve, and a vacuum switch.

Abstract: An automatic fuel boosting system for supplying an optimum amount of fuel to an internal combustion engine based on engine temperature. This fuel boosting system includes a sensor for sensing if the engine temperature at the time of starting is below a predetermined value, an advance angle control circuit, responsive to the sensor, for advancing the ignition angle based on engine temperature, and a solenoid, responsive to the control circuit, for actuating a fuel boosting device so that an optimum amount of fuel is supplied to the intake manifold of the engine based on engine temperature, if the engine temperature is sensed to be below the predetermined value.

Abstract: Fuel injection arrangements having pneumatically driven injection pumps utilize the fluctuating crankcase pressure whereby the injection time point is fixed by the system. The injection time point can be fixed so as to depart from the course of the pressure in the crankcase if the crankcase pressure is applied to the injection pump via an opening controlled by the piston and if the pressure drop is directed to the combustion chamber via a relief opening. However, it has been shown that this kind of control produces considerable problems with respect to fast-running two-stroke engines. Accordingly, it is a feature of the invention to provide a check valve in the connection between the relief opening and the injection pump and to position this check valve so that it opens in the flow direction toward the combustion chamber.

Abstract: The invention is directed to a membrane fuel pump for an internal combustion engine equipped with a membrane carburetor. The engine is that of a working apparatus and especially a handheld portable tool such as a motor-driven chain saw or the like. The membrane pump includes a drive chamber charged with the pressure inside the crankcase of the engine and a pump chamber separated from the drive chamber by a membrane. The pump chamber is connected at its suction end to a fuel tank via a first check valve and is connected to a pressure controller of the membrane carburetor at its pressure end via a second check valve. The pressure end of the membrane pump is connected with the suction end thereof via a bypass and a throttle is mounted in this bypass. With the throttle bypass between the pressure end and the suction end, the pumped volume is reduced at idle and the pump pressure is smoothed. Disturbances at the membrane carburetor are avoided.

Abstract: A marine propulsion system includes a two cycle water cooled crankcase compression internal combustion engine (52) including a vapor separator (33), a remote fuel tank (60), and a fuel pump (62) in the tank for delivering fuel to the engine in response to crankcase pulse pressure. A combination conduit (64) between the fuel tank and the engine includes a first passage (66) communicating crankcase pulse pressure from the engine to the fuel pump in the tank, a second passage (70) supplying fuel from the pump in the tank to the engine, a third passage (74) returing fuel vapor from the vapor separator at the engine back to the tank, a fourth passage (78) supplying cooling water from the engine towards the tank, and a fifth passage (82) returning water from the fourth passage back to the engine.

Abstract: A mechanism for pumping fluid in response to pressure pulses, the mechanism comprising a fluid pump including a reciprocating piston operable to pump fluid, a rotatable eccentric wheel including a cam surface, a linkage engageable with the cam surface for rotating the wheel in response to pressure pulses, and a linkage engageable with the cam surface for causing reciprocation of the piston in response to rotation of the wheel.

Abstract: A fluid pressure actuated motor assembly comprising a first fluid pressure actuated motor including a first reciprocating piston driven by a pressure differential across the first reciprocating piston, and a second fluid pressure actuated motor in communication with the first fluid pressure actuated motor and including a second reciprocating piston driven by the pressure differential across the first reciprocating piston.

Abstract: A fluid driven pump comprising a pump housing defining a recess including therein a moveable wall which divides said recess into a variable volume driving chamber and a variable volume pumping chamber. The pump also includes a pressure inlet communicable with the driving chamber and adapted to communicate with a source of pressure which oscillates between an operating pressure and a pressure different from the operating pressure. The pressure inlet includes a one-way valve for permitting fluid under the operating pressure to communicate with the driving chamber to move the moveable wall in one direction when the driving chamber is in communication with the pressure inlet.

Abstract: Disclosed herein is a combined fuel and oil pump comprising a reciprocally movable member for pumping fuel in response to member reciprocation, a reciprocally movable element for pumping oil in response to element reciprocation, and a fluid pressure actuated motor connected to the member and to the element and responsive to a source of alternating relatively high and low pressures for effecting reciprocation of the member and the element at a frequency less than the frequency of the alternation of the relatively high and low pressures.

Abstract: A system for priming a carburetor for an internal combustion engine which includes a pulse pressure conduit leading from an engine crankcase to a significant portion of a carburetor and a cowl located manually operated valve for opening this conduit during cold starting of an engine. The valve is arranged to have at least three positive positions including "closed" and a plurality of regulated open positions.

Abstract: Disclosed herein is an internal combustion engine including a combustion chamber, a fuel source, a starter mechanism, fuel conduit means connected in communication with the fuel source for introducing fuel into the combustion chamber, fuel pumping means connected in communication with the fuel conduit means and operable for pumping fuel through the fuel conduit means, drive means for operating the fuel pumping means, and means for operatively connecting the drive means with the fuel pumping means when the starter mechanism is activated to thereby prime the engine.

Abstract: A combination primer and pump for internal combustion engines which utilizes a flexible cylindrical housing having a flexing liner with unidirectional valves at each end. The walls of the cylinder permit manual flexing or squeezing to pump fuel and a pulse connection in the outer housing connects the crankcase pulse of an engine being supplied with fuel to the inner, more flexible, liner to permit pumping action to take place when the engine is running. A pressure pulse passage between the outer and inner liner is positioned to be closed when the device is manually squeezed to achieve the priming function.

Abstract: A combination primer and pump for internal combustion engines which utilizes a flexible cylindrical housing having a flexing liner with unidirectional valves at each end. The walls of the cylinder permit manual flexing or squeezing to pump fuel and also a pulse connection in the outer housing serves as a valve to connect the crankcase pulse of an engine being supplied with fuel to the inner liner to permit pumping action to take place when the engine is running. The pulse connection may also serve as a control for the pulse pressure and thus for the fuel flow and pressure.