Acf Industries, Incorporated

Donald L Hicks

Richard D Doerr

Allen W Lindberg

Thomas R Gantzert

Apparatus for controlling the air-fuel ratio in an internal combustion engine to substantially maintain the ratio at a predetermined value while the engine is operating under various load conditions. The engine has a carburetor with an air passageway through which air is drawn into the engine. Fuel is supplied to the carburetor through a fuel system and mixed with air passing through the carburetor. The presence of oxygen in the combustion products, which is a function of the air-fuel ratio of the mixture, is sensed and a first electrical signal representative of the oxygen content is supplied. The first electrical signal is compared with a predetermined reference level which is a function of the predetermined value to produce a second electrical signal having first and second signal elements, a first signal element being produced when the air-fuel ratio of the mixture is greater than the predetermined level and a second signal element being produced when the ratio is less than the level. A control responsive to the second electrical signal supplies to an air metering unit a control signal by which the quantity of air introduced into the fuel system is controlled. A change in the control signal is produced whenever the second electrical signal has a transition from one signal element to the other thereby for the air metering unit to change the quantity of air introduced into the fuel system conduit by an amount necessary to substantially maintain the air-fuel ratio at the predetermined value.

Apparatus for controlling the air-fuel ratio in an internal combustion

A combustible mixture of air and minute fuel droplets is produced for supply to the cylinders of an internal combustion engine. The engine includes a carburetor having a main air passageway in it, and an intake manifold interposed between the engine and the carburetor. The intake manifold includes at least one wall defining a plurality of fluid passageways operatively connected to the carburetor and to the combustion chambers of the engine. A throttle structure is mounted in the intake manifold. The combustible mixture is formed by introducing liquid fuel into a stream of intake air and uniformly distributing the fuel in the air by passing the air and fuel mixture through a constriction to increase the velocity of the mixture to sonic speed. The constriction occurs at the throttle structure in the manifold. The area of the constriction and the amount of fuel entering the air stream are adjustable for correlation with engine demand. After passing through the constriction, the air/fuel mixture is accelerated to supersonic velocity and thereafter decelerated to subsonic velocity to produce a shock zone where the fuel droplets are believed to be further subdivided. The supersonic and subsonic mixture speeds are obtained at the outlet of the throttle structure in the manifold. Thereafter, the mixture is inducted into the combustion chambers of the engine. Preferably, the throttle structure includes a cylinder movably mounted in the intake manifold. A plate either is suspended in or forms a part of the intake manifold. The plate and cylinder coact to provide the constriction, supersonic and subsonic zones of the mixture flow. Means are provided on the cylinder for delimiting those zones of mixture flow.

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St. Louis, MO, United States of America

Donald L Hicks