Abstract: In a fuel feed device for internal combustion engine, the fuel is injected at a rate which is metered responsive to the opening of an auxiliary throttle member located upstream of the driver actuated main throttle member in the intake pipe. For air flow damping purpose, an air filter chamber is located between the auxiliary and main throttle members.

Abstract: The fuel feed device comprises a butterfly valve actuated by the driver and an auxiliary throttle member which opens automatically in proportion to the rate of air-flow in the intake passage of the engine. The pressure of the fuel which is delivered into the intake at a location downstream of the butterfly by an injector is adjusted by an unloading valve. The fuel pressure tends to open the unloading valve and the under-pressure which prevails in a control chamber tends to close it. The control chamber has a connection with a portion of the intake which is located downstream of the auxiliary throttle member. That connection is open when the under-pressure is moderate. The connection has also a branch connected to an additional air channel for cold running of the engine which is open when the temperature of the engine is lower than a predetermined value.

Abstract: A carburetor has a main throttle and an auxiliary throttle which is automatically opened in proportion to the air flow in the induction pipe. Fuel is delivered to the induction pipe through a passage whose cross-section is metered in accordance with the position of the auxiliary throttle. The richness of the air-fuel mixture is automatically adjusted by a system comprising a probe which is sensitive to the conditions prevailing in the exhaust pipe. The system periodically opens an air path to the fuel passage and the duration of each opening period is automatically determined for a correct richness to be achieved.

Abstract: A carburettor throttle member is provided with two return springs. The first spring is tensioned between the carburettor body and a disk rotatably mounted on the carburettor shaft. The second spring is weaker than the first spring and is compressed between the disk and shaft. The two springs tend to rotate the disk in opposite direction. The first spring normally retains the disk and shaft in a predetermined angular position. In case of fracture of the first spring, the second spring moves the disk into abutment with the fixed stop, operates as a substitute return spring.

Abstract: A carburettor comprises an idling circuit having an idling duct delivering a fuel air mixture into the intake conduit and an air duct. The air duct has a restricted passage provided with an adjusting screw. The idling duct is connected to a second passage of the air duct whose section is manually adjustable by the adjusting screw simultaneously with the first passage.