Importance

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Abstract

An internal combustion engine has an exhaust manifold, an inlet manifold, and a carburetor which has a fuel jet. An oxygen sensor is mounted within the exhaust manifold, and produces an output signal according to the oxygen present within the exhaust gases. A computing means computes a corrective signal according to the oxygen sensor output signal. This corrective signal is fed as an input signal both to a means for supplying secondary air into the exhaust manifold, and also to a means for supplying bleed air to the jet of the carburetor. In a particular embodiment, a secondary air signal cutoff device selectively intercepts supply of the corrective signal to the secondary air supply means, and an air bleed signal cutoff device selectively intercepts the supply of the corrective signal to the air bleed supply means. These cutoff devices may be controlled according to vehicle road speed, engine temperature, engine rotational speed, inlet manifold vacuum, and the temperature of a catalytic converter. The corrective signal may be a duty ratio coded pulse signal.

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First Claim