Fuel supply control system for internal combustion engines

Claim 1

A fuel supply control system for an internal combustion engine having electro-magnetic valves for controlling the quantity of fuel supplied to the engine cylinders comprising: a first transistor circuit, responsive to an input fuel supply signal, for controlling the activation of said valves to supply fuel to said engine; a second transistor circuit, connected to said first transistor circuit, which, when activated, prevents said first transistor circuit from being activated by said input fuel supply signal; and means, responsive to the engine r.p.m. being above a predetermined value and upon the rate of change of the position of the engine throttle in the direction of closing the engine throttle valve exceeding a predetermined rate, for actuating said second transistor circuit, so as to prevent said first transistor circuit from actuating said valves, wherein said means comprises a first control circuit, coupled to said throttle, for deactivating said second transistor circuit upon the opening of said throttle, and for activating said second transistor circuit for a preselected period of time subseQuent to the rate of change of position of said throttle valve, in the direction of closing the throttle valve, exceeding said predetermined rate, when said throttle remains in an intermediate position between the fully closed and fully open position thereof, and wherein said first control circuit comprises monostable multivibrator circuit means for producing an output for said preselected period of time and having a time constant portion which determines said preselected period of time, the time constant portion of which is switchably coupled to said throttle, having its output coupled to said second transistor circuit.