Fuel injection system

Claim 1

In a fuel injection system for a mixture-compressing spark ignition internal combustion engine including an intake manifold having continuous fuel injection into the engine intake manifold, comprising a source of pressurized fuel, a fuel injection nozzle, an adjustable throttle valve in the manifold, a flow sensing element in the intake manifold arranged to move in accordance with the quantity of air flowing through the manifold, a fuel-metering valve operated by said flow sensing element for dispensing a quantity of fuel related to the quantity of air to said nozzle, a constant pressure valve arranged to ensure a substantially constant pressure differential across the metering valve, and a differential pressure regulating valve, each of said constant pressure valve and differential pressure regulating valve having a first and second chambers and a movable partition element separating said chambers from each other, first and second means for communicating the first chamber of the constant pressure valve via said metering valve with said source and with said nozzle respectively, third and fourth means for communicating the first chamber of the differential pressure regulating valve with the second chamber of the constant pressure valve and with a return line respectively, said fourth means including a spring-loaded valve controlled by the movable partition element of the differential pressure regulating element and means for communicating the second chamber of the differential pressure regulating valve to the pressure upstream of the metering valve, the improvement being that a passage is included for directly connecting the two chambers of the constant pressure valve to each other.