Fuel injection system

Claim 1

In a fuel injection system for externally ignited, internal combustion engines having means for continuously injecting combustion air into an induction tube means including a funnelshaped section and in which a measuring member and a randomly activatable throttle valve are arranged in series, said measuring element being displaceable against a restoring force by a working member in accordance with the amount of air flowing through, and an adjustable mobile part of a valve disposed in a fuel line for metering out a quantity of fuel proportional to the quantity of air, the restoring force being provided by pressure fluid which is passed in a continuous manner under constant but randomly variable pressure through a pressure line and which acts on said working member, said measuring member being a plate which is secured, in its quiescent position, at a right angle to the flow direction on one end of a pivoted lever mounted in a substantially friction-free manner, said measuring member projecting proportionally to the amount of air flowing through said induction tube means into a corresponding portion of said funnel-shaped section of said induction tube means extending in the flow direction, the improvement comprising a spring having a substantially linear characteristic positioned in the vicinity of said measuring member for providing a force against which said measuring member must act as it passes backwardly past its quiescent position during backfiring in said induction tube means, and an elastic stop means behind said measuring member for arresting backward motion thereof.