US 5,845,624 A · Air-fuel ratio control system for internal combustion engine

Abstract

In an air-fuel ratio control system for an internal combustion engine, a fuel injection amount to be injected from a fuel injector is set based on a monitored operating condition of the engine. The fuel injector injects a corresponding amount of fuel to the engine. An air-fuel ratio sensor monitors exhaust gas discharged from the engine and detects an air-fuel ratio. The system derives an injector sensitivity based on a current fuel injection amount and an output of the air-fuel ratio sensor and further derives, as an injector sensitivity deviation, a ratio between the derived injector sensitivity and an injector sensitivity estimated upon designing the system. The system further derives a sensitivity correction term based on the derived injector sensitivity deviation so as to correct the injector sensitivity. The system may also correct an air-fuel ratio sensor sensitivity in a similar manner.

Claims6

Dependent claims

An air-fuel ratio control system for an internal combustion engine, comprising:

a fuel injector for injecting fuel to the engine;
setting means for sequentially setting fuel injection amounts to be injected from said fuel injector;
measuring means for measuring an accumulated value of fuel amounts actually injected from said fuel injector;
injector sensitivity measuring means for measuring a sensitivity of said fuel injector based on an accumulated value of the fuel injection amounts set by said setting means and the accumulated value of the fuel amounts measured by said measuring means;
and
injector sensitivity correcting means for correcting the sensitivity of said fuel injector, said injector sensitivity correcting means deriving a sensitivity correction value based on said measured sensitivity of said fuel injector such that a sensitivity of a virtual fuel injector constituted by said fuel injector and said injector sensitivity correcting means becomes equal to a preset injector sensitivity.

3 more elements

Dependencies are inferred from the claim text.

Air-fuel ratio control system for internal combustion engine

Life of this patent

Air-fuel ratio control system for internal combustion engine

Life of this patent

Abstract

Claims6