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.