Abstract: A device for the regulation of the air-fuel mixture of internal combustion engines comprises a fuel gas or air inlet opening into the inlet manifold downstream of the throttle valve, the gas inlet being controlled by a valve which is controlled by a capsule containing a movable member such as a membrane or piston subject to the partial vacuum prevailing in the manifold, the partial vacuum being modulated as a function firstly of the inlet air flowrate and secondly of the composition of the exhaust gases.

Abstract: A device for the regulation of the air-fuel mixture of an internal combustion engine, comprising two capsules, each divided into two chambers by an element which is movable in response to a pressure difference between the two chambers, the two movable elements being connected to each other and to a valve which regulates a gas inlet to the manifold, the two chambers of one capsule being subject respectively to the static and dynamic pressures in an inlet pipe to the manifold and the two chambers of the other capsule being subject to the pressure in the manifold and a valve for altering the pressure in one of the four chambers in response to the composition of the exhaust gases.

Abstract: In a carburettor, the dosing needle for regulating the fuel flow is connected to a second movable element, such as a membrane or piston, the second movable element being movable relative to a first movable element, one side of the second movable element being subject to atmospheric pressure and the other side of the second movable element being subject to the partial vacuum prevailing upstream of the throttle valve, modulated by an electromagnetic valve capable of supplying atmospheric pressure, the electromagnetic valve being controlled by a probe arranged in the exhaust pipe which supplies a signal representative of the composition of the exhaust gases.

Abstract: An internal combustion engine of a known design includes a device for correcting the air-fuel dose. The device has a gas inlet connected to the induction manifold, and a control valve controlling the gas inlet. The control valve is controlled by the negative pressure at the throat of a venturi by means of a control means including a spring biassed diaphragm and subjected to the negative pressure. The said pressure may be modified by an electromagnetic valve controlled by means of a probe positioned in the exhaust manifold, which delivers electrical current varying in accordance with the burned gases. This current controls, via an electronic device, and electromagnetic valve.

Abstract: A fuel injection control system for an internal combustion engine comprises at least one auxiliary air supply branched at the engine intake pipe downstream of the air-fuel metering system, and at least one valve controlling the auxiliary air supply. The valve is controlled by a diaphragm with a return-spring membrane subjected to a partial vacuum from any suitable source which is modulated on one hand by at least one variable throttle or choke responsive to the air flow in the metering system and, on the other hand, by an electronic valve controlled by a probe responsive to the composition of burnt gases in the exhaust manifold.

Abstract: A device for correcting the proportioning of the air/petrol mixture furnished by a proportioning means to an internal combustion engine comprising a probe producing a signal which is a function of the oxygen or carbon monoxide content of engine exhaust gas and an auxiliary air admission valve downstream of the air/petrol proportioning means, this valve being periodically operable by control means sensitive to said signal.

Abstract: The adjustable aperture of a petrol metering element of a carburetor for internal combustion engines discharges directly into the body of the carburetor and is centered substantially on the geometrical axis of the stream of air in the said body, the petrol clearance height not being greater than about 10 mm.

Abstract: A carburettor for an internal combustion engine includes a chamber into which fuel is introduced from a metering valve to produce a fuel/air mixture in the chamber. A main valve controls the rate of flow of fuel/air mixture from the chamber and a further valve upstream of the main valve is provided the opening of which controls the opening of the metering valve. The further valve opens so as to keep the pressure between the main and further valve constant with changes in flow rate through the chamber. Means are provided to provide an indication of the pressure of fuel/air mixture downstream of the main valve such that the metering valve can be further opened as a function of changes in said pressure downstream of the main valve.

Abstract: At least one auxiliary air inlet is provided. The inlet is controlled by at least one valve communicating with the inlet pipe of the engine downstream of a device determining the proportion of air and fuel supplied to the engine, such as a carburettor. The valve is controlled by the vacuum from the proportioning device via a capsule including a diaphragm biased by a spring. The vacuum is modulated by an electromagnetic valve controlled by a sensor positioned in the exhaust pipe. The sensor delivers to the electromagnetic valve an electric current variable as a function of the composition of the burnt gases.