Fuel-metering unit for internal combustion engines

Claim 2

In a fuel-metering unit adapted for use in an internal combustion engine having an exhaust pipe which unit comprises an air-intake suction tube, a randomly adjustable throttle valve therein, an air-measuring device mounted in said suction tube upstream of said throttle valve, by-pass means connected with said suction tube both upstream and downstream of said airmeasuring device thereby bypassing said air-measuring device and means for metering fuel in amounts substantially proportional to the amount of air flowing through said suction tube past said air-measuring device, the improvement comprising: a solenoid valve; control valve means associated with said by-pass means and adapted for controlling opening of said by-pass means and thereby the amount of air passing said air-measuring device thereby varying the proportionality of fuel and air in dependence on characteristic engine data; and an exhaust gas-measuring probe adapted to be mounted in said exhaust pipe and adapted for controlling said control valve means, wherein: said control valve means comprises control conduit means opening into said suction pipe and a by-pass valve adapted for pneumatic actuation via said control conduit means; and said solenoid valve is interposed in said control conduit means and is controlled by said exhaust gas-measuring probe.

Claim 3

The improvement as described in claim 1, wherein said by-pass valve is a membrane valve.

Claim 4

The improvement as described in claim 1, wherein said control conduit means open into said suction tube downstream of said throttle valve.

Claim 5

The improvement as described in claim 1, wherein said throttle valve has a flap portion moving against the air flow through said suction tube when the position of said throttle valve in the latter is opened, said by-pass means opening in said suction tube upstream of said throttle valve and within the reach of said flap portion moving against said air flow, whereby, when said throttle valve is being opened, the air pressure prevailing in said suction tube downstream of said throttle valve also prevails at the opening of said by-pass means in said suction tube.

Claim 6

The improvement as described in claim 4, wherein said by-pass means comprise throttle means disposed at the opening of said by-pass means into said suction tube.

Claim 7

The improvement as described in claim 5, wherein the internal cross-sectional area of said throttle means is circular, rectangular or oval.

Claim 8

The improvement as described in claim 5, wherein said throttle means have two orifices opening into said suction tube successively in the direction of air flow.

Claim 9

In a fuel-metering unit adapted for use in an internal combustion engine having an exhaust pipe which unit comprises an air-intake suction tube, a randomly adjustable throttle valve therein, an air-measuring device mounted in said suction tube upstream of said throttle valve, by-pass means connected with and opening into said suction tube both upstream and downstream of said air-measuring device thereby bypassing said air-measuring device and means for metering fuel in amounts substantially proportional to the amount of air flowing through said suction tube past said air-measuring device, the improvement comprising: a solenoid valve; control valve means associated with said by-pass means and adapted for controlling opening of said by-pass means and thereby the amount of air passing said air-measuring device thereBy varying the proportionality of fuel and air in dependence on characteristic engine data; and an exhaust gas-measuring probe adapted to be mounted in said exhaust pipe and adapted for controlling said control valve means, wherein: said control valve means comprises control conduit means opening into said suction pipe and a by-pass valve connected in said by-pass means at a location remote from the opening of the by-pass means downstream of said air-measuring device, said by-pass valve being adapted for pneumatic actuation via said control conduit means; and said solenoid valve is interposed in said control conduit means and is controlled by said exhaust gas-measuring probe.

Claim 10

In a fuel-metering unit adapted for use in an internal combustion engine having an exhaust pipe which unit comprises an air-intake suction tube, a randomly adjustable throttle valve therein, an air-measuring device mounted in said suction tube upstream of said throttle valve, by-pass means connected with and opening into said suction tube both upstream and downstream of said air-measuring device thereby bypassing said air-measuring device and means for metering fuel in amounts substantially proportional to the amount of air flowing through said suction tube past said air-measuring device, the improvement comprising: a solenoid valve; control valve means associated with said by-pass means and adapted for controlling opening of said by-pass means and thereby the amount of air passing said air-measuring device thereBy varying the proportionality of fuel and air in dependence on characteristic engine data; and an exhaust gas-measuring probe adapted to be mounted in said exhaust pipe and adapted for controlling said control valve means, wherein: said control valve means comprises control conduit means opening into said suction pipe and a by-pass valve connected in said by-pass means at a location remote from the opening of the by-pass means downstream of said air-measuring device, said by-pass valve being adapted for pneumatic actuation via said control conduit means; and said solenoid valve is interposed in said control conduit means and is controlled by said exhaust gas-measuring probe.