Fuel supply device for internal combustion engine

Claim 1

A fuel supplying device for an internal combustion engine comprising: an intake pipe, operator actuatable main throttle means in said pipe, auxiliary throttle means located in said intake pipe upstream of said main throttle means, said auxiliary throttle means automatically and progressively opening in proportion to the increase in the flow rate of air in said intake pipe, a source of fuel under pressure having a delivery circuit which opens into a portion of the intake pipe downstream of the main throttle means, first solenoid valve means controlling the flow of fuel in said delivery circuit, a metering system which is responsive to the degree of opening of the auxiliary throttle means having means delivering repeating pulse signals and arranged to supply said first solenoid valve means with at least one energization signal per pulse signal repetition period, said energization signal being applied for a fraction of the repetition period which depends on said degree of opening, and pressure regulator means with said delivery circuit and including a relief valve having a closure member, said relief valve being subjected to an opening force by the fuel pressure in said delivery circuit and subjected to a closure force by the vacuum in a control chamber connected by connecting duct means to that portion of the intake pipe between the two throttle means, second solenoid valve means controlling communication between said duct means and the atmosphere, and an energizing electric circuit for said second solenoid valve comprising means responsive to at least one engine operating parameter which is modified upon a change in the fuel injection pressure, said electric circuit supplying said second solenoid valve with repetitive excitation signals having a duration which varies in dependence on said parameter, the total time during which the second solenoid valve means is fully open during a predetermined time period depending upon the value of said parameter.