Abstract: A fuel injection valve comprises a hollow body in which there is formed a fuel circuit having an outlet opening. A guide member has a stem located in the passage and secured to the body. A bulged end portion of the guide member projects through the opening and is formed with a valve seat surface. An annular valve closure member is slidably mounted on the guide member and sealingly movable in the opening. A coil in the body is adapted to move a valve closure member into an abutment position clear from the seat. When the valve closure member is in that open position, a conical jet of fuel is delivered by the valve.

Abstract: For determining the amount of wear of the movable parts of a carburetor, the throttle of the carburetor is retained in a position where it defines a predetermined cross-sectional flow area with the whole of the induction passage. That predetermined area is the area for which, when the carburetor was new, the edge of the throttle was midway along the bypass aperture of the idling circuit. The degree of vacuum in the idling circuit of the carburetor is then compared with a reference value which is the degree of vacuum which prevails on the carburetor in brand new condition under the same operating conditions.

Abstract: A constant depression carburettor has an auxiliary throttle member associated with a sensor which delivers a signal representative of the position of the auxiliary throttle member. A solenoid valve is actuated by pulses received from a control circuit which receives input signals from sensor. The solenoid valve meters the fuel delivered to the intake passage via a discharge orifice located at the throat of a venturi limited by a swelling of the intake passage and by the throttle.

Abstract: A carburettor for an internal combustion engine comprises a main fuel supply system for normal running, opening into a venturi in the induction passage of the carburettor, and at least one auxiliary circuit for supplying a flow of air/fuel mixture for low speed and low-load operation of the engine. The mixture control means for the circuits are carried by a distribution block arranged to be inserted and removably fixed in the part of the induction passage situated in the vicinity of the venturi.

Abstract: An idling circuit for a carburation device comprises an idling duct for supplying a primary air-fuel mixture downstream of the throttle and a fueled-air line having an adjustable cross-section for circulating an additional quantity of air and primary mixture from upstream to downstream of the throttle. A solenoid valve is energized by pulses having a duty cycle which is controlled so as to keep the engine speed near a set idling speed and so as to increase the amount of mixture supplied to the engine during deceleration at high speed.

Abstract: A fuel control system comprises a probe in contact with the exhaust gases, a circuit for supplying fuel and air to the engine, having a solenoid valve for metering at least the fuel flow, a closed-loop electronic control circuit connected to the probe and energizing the solenoid valve in dependence on the signal from the probe. The loop is opened responsive to predetermined operating conditions of the engine. Further means control the solenoid valve in dependence on another engine operating parameter during open-loop operation. A memory is provided for storing a value representative of the control of the solenoid valve means during closed-loop operation.

Abstract: A fuel supply device for an internal combustion engine having at least two groups of combustion chambers, each group having a separate exhaust pipe, comprises a carburettor which delivers a mixture whose air/fuel ratio is adjusted responsive to the composition of the exhaust gases of the "richer" group. The carburettor is connected to a manifold having two branches each associated with one group. The branch feeding the "leaner" group is provided with an air/fuel ratio correction circuit comprising a solenoid valve controlled by a circuit whose input detector is located in the exhaust pipe of the "leaner" group.

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: A carburetor for an internal combustion engine has an auxiliary starting device for delivering fuel and air to the induction passage during starting and cold running. The starting device comprises a duct opening into the induction passage downstream of the throttle means receiving fuel and air, and provided with a closure valve opened until the temperature of the engine has reached a first predetermined value. The flow of fuel entering the duct is reduced upon the engine becoming self operative. A flap located in the induction passage upstream of the opening of the main fuel delivery system is biased toward opening by the air flow around it and is resiliently biased toward closure with a force which decreases as the temperature of the engine increases.

Abstract: A fuel supply device comprising auxiliary throttle means located in the intake pipe upstream of an operator actuatable throttle means and a source of pressurized fuel comprising a delivery circuit which opens into a portion of the intake pipe downstream of the main throttle means, the delivery circuit being controlled by at least one solenoid valve. A metering system, which is sensitive to the degree of opening of the auxiliary throttle means, has means supplying repeating pulse signals. The metering system supplies the solenoid valve with one energization signal per pulse signal repetition period which has a duration equal to a fraction of the period which is adjusted by the metering system. The source of fuel has a pressure regulator comprising a relief valve which is biased toward opening by the fuel delivery pressure and toward closure by the vacuum in a chamber connected to the intake pipe. The chamber is bounded by a diaphragm, to which the closure member of the valve is connected.

Abstract: A carburettor for an internal combustion engine comprises an air valve and a driver-actuatable throttle in an induction pipe. The air valve controls proportioning means metering the flow rate of fuel drawn into the induction pipe downstream of the main throttle means via a discharge orifice. A fuel pressure regulator is disposed between the fuel proportioning means and the discharge orifice for controlling the pressure of the fuel discharged into the induction pipe and comprises a valve actuated by a diaphragm one face of which limits a control chamber communicated with that portion of the induction pipe located between the throttle and the air valve. The other surface is subjected to the fuel pressure prevailing upstream of the valve.

Abstract: A carburetor for an internal combustion engine comprises a fuel idling circuit opening into the intake pipe downstream of a driver-actuated main throttle. Idle regulation means comprise a first pneumatic element connected to that part of the intake pipe downstream of the main throttle and a second pneumatic element having a movable part connected to the main throttle means by a unidirectional connection such that the throttle means can be opened to an additional extent. The second pneumatic element is subjected to the vacuum in a chamber connected to said part of the intake pipe and also connected to atmosphere by a valve carried by the movable part of the second element and opened by the first pneumatic element moving with respect to the second pneumatic element when there is an increase in the degree of vacuum in the intake pipe. Additional means preventing the main throttle from closing beyond a partially open position and which are disabled after successful cranking may be provided.

Abstract: A fuel injection device comprises an air valve located upstream of an operator actuated throttle in the air intake passage. The air valve is actuated by airflow through the passage and opens in proportion to the increase in the flow rate of air. Fuel under pressure is delivered to the air passage through an electrically energized injector valve. A metering system which is sensitive to the position of the air valve supplies the valve with repetitive electrical pulses during normal operation of the engine. During cranking, the metering system delivers a continuous energization signal to the valve for maintaining it permanently open. The pressure of the fuel delivered to the valve is substantially decreased during cranking, i.e. as long as a continuous energization signal is delivered to the injector valve.

Abstract: The pneumatic element which causes partial opening of the choke valve is connected to the intake pipe by a duct having a calibrated restriction. The duct opens into the pipe at a point which is located downstream of the throttle valve under all operating conditions and at another point which is downstream of the throttle when the latter is in the "cold" minimum opening position.

Abstract: A carburetor for an internal combustion engine comprises a fuel idling circuit opening into the intake pipe downstream of a driver-actuated main throttle. Idle regulation means comprise a first pneumatic element connected to that part of the intake pipe downstream of the main throttle and a second pneumatic element having a movable part connected to the main throttle means by a unidirectional connection such that the throttle means can be opened to an additional extent. The second pneumatic element is subjected to the vacuum in a chamber connected to said part of the intake pipe and also connected to atmosphere by a valve carried by the movable part of the second element and opened by the first pneumatic element moving with respect to the second pneumatic element when there is an increase in the degree of vacuum in the intake pipe.

Abstract: A carburetor for an internal combustion engine has a circuit for delivering a primary air/fuel mixture into the induction passage and means for correcting the richness of the airfuel mixture in dependence of the amplitude of the alternating component of the depression which prevails in operation in the induction passage. The correction device has a movable member which meters an air or fuel flow cross-sectional area in the circuit. The position of the movable member is controlled in dependence of the alternating component by a pressure sensitive diaphragm. A frequency filter connects the induction passage and chambers separated by the diaphragm for dampening the alternating component of the depression by an amount which increases with the frequency of that component.

Abstract: A carburation device has auxiliary throttle means and a main throttle. The auxiliary throttle means opens automatically in proportion to the increase in the flow rate of air and actuates proportioning means metering the flow rate of fuel drawn into the intake pipe, downstream of the main throttle via a passage. The passage includes a chamber which is kept at a pressure substantially equal to the pressure in the portion of the intake pipe between the throttle means by a bypass passage connecting said portion and chamber, having means which are sensitive to at least one engine operating parameter and which, in operation, adjust a control cross-sectional area in the passage means between the chamber and the intake pipe.

Abstract: A carburetor has an operator operable butterfly valve and an auxiliary throttle located upstream of the butterfly valve. The auxiliary throttle is urged toward closure by temperature sensitive thermostatic means and is urged toward opening by the airflow drawn by the engine. A pneumatic element subjected to the pressure downstream of the butterfly valve opens the auxiliary throttle to a predetermined extent immediately after cranking. A pneumatic device responsive to the depression downstream of the butterfly valve urges the auxiliary throttle toward closure when the butterfly valve is abruptly opened while the engine is cold. The action of that pneumatic device is of short duration, and consequently the auxiliary throttle returns to its partially open position as acceleration proceeds.

Abstract: A fuel supply device for internal combustion engines has an injector formed with an injection orifice whose cross-sectional area is adjusted responsive to the position of an auxiliary throttle element located in the intake pipe of the engine and opening automatically and progressively in dependence upon the rate of engine intake air flow. The area is also adjusted as an increasing function of the difference between the pressures upstream and downstream of the auxiliary throttle element.

Abstract: An automatic cold start and warmup system for an internal combustion engine carburetor comprises a coiled bimetallic spring element actuating a choke valve mounted across the induction passage of the carburetor to control air flow therethrough. Two PTC heating resistors are located in heat-transfer relation with the bimetallic element, have different switching temperatures and are connected in series with a source. A switch closes above a predetermined temperature level of the engine and short-circuits the resistor having the lower switching temperature.