Fuel injection apparatus for externally ignited internal combustion engines operating on continuously injected fuel

Claim 1

In a fuel injection apparatus serving an externally ignited internal combustion engine operating on fuel continuously injected into the suction tube of the engine, said engine having an arbitrarily operable butterfly valve situated in said suction tube, said fuel injection apparatus being of the known type that has (a) an air sensor situated in said suction tube, said air sensor being deflected by and as a function of the air quantities flowing through said suction tube, (b) a control plunger operatively connected with Said air sensor, (c) a pressurized liquid circuit for exposing said control plunger to liquid pressure to cause said control plunger to exert a return force on said air sensor in opposition to the deflecting force exerted thereon by said air quantities, said return force being independent from the position of said control plunger, (d) means for continuously supplying said pressurized liquid circuit with pressurized liquid, (e) a pressure control valve situated in said pressurized liquid circuit for controlling the liquid pressure affecting said control plunger, said pressure control valve having a movable valve member, (f) a spring forming part of said pressure control valve and loading said movable valve member, (g) a first temperature-dependent control element connected to said spring for varying the bias thereof, (h) a second temperaturedependent control element affecting said movable valve member for a short period immediately after engine start and (i) a fuel metering and distributor valve having a movable component displaceable by said air sensor for metering fuel in proportion to said air quantities flowing through said suction tube, the improvement comprising means for additionally varying the bias of said spring during the warm-up run of the engine as a function of the pressure in said suction tube downstream of said butterfly valve.