Fuel feed devices for internal combustion engines

Claim 1

Fuel feed device, for an internal combustion engine, comprising in an inlet conduit, upstream of a principal throttle member adapted to be actuated by the operator, an auxiliary throttle member which opens automatically and progressively as the air-flow rate in said conduit increases, and means for injecting liquid fuel under pressure into the portion of this conduit situated downstream of the principal throttle member and, a metering system sensitive to the position of the auxiliary throttle member and adapted to regulate the flow-rate of the fuel injected in such a way that the richness of the air/fuel mixture passing in the inlet conduit is substantially constant, at least for certain conditions of operation of the engine, the above-said injection means being constituted by a source of fuel under pressure of which the delivery circuit opening into the said portion of the inlet conduit is controlled by at least one valve actuated by an electromagnet, the metering system comprising a member driven in a movement of continuous rotation and capable, by acting on the energization of the electromagnet, of determining over a fraction only of each of these revolutions, the opening of the valve, said system being arranged so that it increases the said fraction in proportion as the opening of the auxiliary throttle member increases and vice-versa, the said source of fuel under pressure being constituted by a fuel pump in whose delivery circuit acts a pressure regulator which comprises a relief valve tending to open under the action of the delivery pressure of the pump and to close under the action of the suction existing in the section of the inlet conduit comprised between its two throttle members, which suction is transmitted through a connecting passage to a diaphragm to which the relief valve is coupled, characterized by the fact that an elastic element which engages said relief valve and is deformable under the effect of the variation of temperature, is arranged to exert on said relief valve, a force directed in the sense of its closing which increases (in algebraic value) in proportion as the temperature decreases.