Fuel injection system

Claim 2

In a fuel injection system for externally ignited internal combustion engines including: a. a suction tube for air intake to the engine; b. an air sensor disposed in said suction tube; c. an arbitrarily operable throttle valve disposed in said suction tube in series with said air sensor; d. a fuel supply conduit; e. a control pressure conduit; f. a fuel metering valve connected to said fuel supply conduit and said control pressure conduit for continuously injecting fuel into said suction tube, said fuel metering valve having a pressure chamber defined therein; g. a control plunger, serving as the movable member of said fuel metering valve, said control plunger being acted upon on one end by said air sensor, and on an opposite end, which extends into said pressure chamber, by a return force provided by liquid under constant but arbitrarily variable pressure delivered by said control pressure conduit, for metering a fuel quantity that is proportionate to the quantity of air flowing through the suction tube and measured by said air sensor; and h. a pressure control valve connected to the control pressure conduit for varying the pressure in said control pressure conduit in dependence on at least one operating parameter of the engine, said pressure control valve having a temperature-dependent control element disposed therein, the improvement comprising: i. a relief valve connected to the control pressure conduit and the pressure chamber, said relief valve having a housing connected to the fuel metering valve, in the wall of which there is defined a relief conduit between the control pressure conduit and the pressure chamber, which is effective when a sudden acceleration occurs during the warm-up phase of the engine operation to reduce the pressure in the pressure chamber for a short period of time, and wherein in the course of the above pressure reduction the pressure control valve causes the pressure in the control pressure conduit to be reduced; and ii. means forming part of said relief valve and defining a damping throttle mounted in said housing, said damping throttle being disposed between the control pressure conduit and the pressure chamber so that said relief valve is controllable in dependence on the pressure drop at said damping throttle.

Claim 3

In a fuel injection system for externally ignited internal combustion engines including: a. a suction tube for air intake to the engine; b. an air sensor disposed in said suction tube; c. an arbitrarily operable throttle valve disposed in said suction tube in series with said air sensor; d. a fuel supply conduit; e. a control pressure conduit; f. a fuel metering valve connected to said fuel supply conduit and said control pressure conduit for continuously injecting fuel into said suction tube, said fuel metering valve having a pressure chamber defined therein; g. a control plunger, serving as the movable member of said fuel metering valve, said control plunger being acted upon on one end by said air sensor, and on an opposite end, which extends into said pressure chamber, by a return force provided by liquid under constant but arbitrarily variable pressure delivered by said control pressure conduit, for metering a fuel quantity that is proportionate to the quantity of air flowing through the suction tube and measured by said air sensor; and h. a pressure control valve connected to the control pressure conduit for varying the pressure in said control pressure conduit in dependence on at least one operating parameter of the engine, said pressure control valve having a temperature-dependent control element disposed therein, the improvement comprising: i. a relief valve connected to the control pressure conduit and the pressure chamber, said relief valve having a relief conduit, which is effective when a sudden acceleration occurs during the warm-up phase of the engine operation to reduce the pressure in the pressure chamber for a short period of time, wherein in the course of the above pressure reduction the pressure control valve causes the pressure in the control pressure conduit to be reduced; ii. means forming part of said relief valve and defining a damping throttle, said damping throttle being disposed between the control pressure conduit and the pressure chamber so that said relief valve is controllable in dependence on the pressure drop at said damping throttle; and iii. a diaphragm forming part of said relief valve, said diaphragm being exposed on one side to the pressure in the control pressure conduit and on the other side to atmospheric pressure, wherein the means defining the damping throttle comprises a movable valve part of the relief valve which has a smaller diameter than the diaphragm, and wherein the movable valve part is controlled in its movement by the diaphragm so that the pressure in the pressure chamber may be exerted on the movable valve part.

Claim 4

In a fuel injection system for externally ignited internal combustion engines including: a. a suction tube for air intake to the engine; b. an air sensor disposed in said suction tube; c. an arbitrarily operable throttle valve disposed in said suction tube in series with said air sensor; d. a fuel supply conduit; e. a control pressure conduit; f. a fuel metering valve connected to said fuel supply conduit and said control pressure conduit for continuously injecting fuel into said suction tube, said fuel metering valve having a pressure chamber defined therein; g. a control plunger, serving as the movable member of said fuel metering valve, said control plunger being acted upon on one end by said air sensor, and on an opposite end, which extends into said pressure chamber, by a return force provided by liquid under constant but arbitrarily variable pressure delivered by said control pressure conduit, for metering a fuel quantity that is proportionate to the quantity of air flowing through the suction tube and measured by said air sensor; and h. a pressure control valve connected to the control pressure conduit for varying the pressure in said control pressure conduit in dependence on at least one operating parameter of the engine, said pressure control valve having a temperature-dependent control element disposed therein, the improvement comprising: i. a relief valve connected to the control pressure conduit and the pressure chamber, said relief valve having a relief conduit, which is effective when a sudden acceleration occurs during the warm-up phase of the engine operation to reduce the pressure in the pressure chamber for a short period of time, wherein in the course of the above pressure reduction the pressure control valve causes the pressure in the control pressure conduit to be reduced; ii. means forming part of said relief valve and defining a damping throttle, said damping throttle being disposed between the control pressure conduit and the pressure chamber so that said relief valve is controllable in dependence on the pressure drop at said damping throttle; and iii. a diaphragm forming part of said relief valve, said diaphragm being exposed on one side to the pressure in the control pressure conduit and on the other side to atmospheric pressure, wherein the means defining the damping throttle comprises a movable valve part of the relief valve which has a smaller diameter than the diaphragm, and wherein the movable valve part is controlled in its movement by the diaphragm so that the pressure in the pressure chamber may be exerted on the movable valve part.

Claim 5

The fuel injection system as defined in claim 2, wherein the movable valve part is formed as a sleeve valve which is rigidly connected at one end to the diaphragm.

Claim 6

The fuel injection system as defined in claim 3, wherein the sleeve valve has an axial bore formed therein, said axial bore serving to define the damping throttle and connect the pressure chamber and the control pressure conduit.

Claim 7

The fuel injection system as defined in claim 3, wherein the relief valve further includes a flexible packing ring disposed at the end of the sleeve valve which is remote from the diaphragm.