Catalyst deterioration detecting device and catalyst deterioration detecting method
AssigneeToyota Jidosha Kabushiki Kaisha
InventorHiroshi Sawada
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Abstract
A catalyst deterioration detecting device of the invention has exhaust emission purifying catalyst on an exhaust passage of an internal combustion engine and air-fuel ratio sensors provided upstream and downstream of the exhaust emission purifying catalyst, respectively, and detects the deterioration of the exhaust emission purifying catalyst based on the outputs of the air-fuel ratio sensors. An index characteristic value of catalyst deterioration is calculated from the outputs of the air-fuel ratio sensors, a time-lapse changing ratio of the calculated index characteristic value of catalyst deterioration is calculated, and the deterioration of the exhaust emission purifying catalyst is determined based on the calculated time-lapse changing ratio.
Claims12
A catalyst deterioration detecting device comprising:
- an exhaust emission purifying catalyst arranged on an exhaust passage in an internal combustion engine;
- a first air-fuel ratio sensor arranged upstream of the exhaust emission purifying catalyst;
- a second air-fuel ratio sensor arranged downstream of the exhaust emission purifying catalyst;
- and
- a controller which calculates an index characteristic value of catalyst deterioration from a first output value of the first air-fuel ratio sensor and a second output value of the second air-fuel ratio sensor, calculates a time-lapse changing ratio of the index characteristic value of catalyst deterioration and determines the deterioration of the exhaust emission purifying catalyst based on the time-lapse changing ratio.
A catalyst deterioration detecting method having exhaust emission purifying catalyst arranged on an exhaust passage of an internal combustion engine, a first air-fuel ratio sensor arranged upstream of the exhaust emission purifying catalyst and a second air-fuel ratio sensor arranged downstream of the exhaust emission purifying catalysts comprising steps of:
- calculating an index characteristic value of catalyst deterioration from a first output value of the first air-fuel ratio sensor and a second output value of the second air-fuel ratio sensor;
- calculating a time-lapse changing ratio of the index characteristic value of catalyst deterioration;
- and
- carrying out the determination of the deterioration of the exhaust emission purifying catalyst based on the time-lapse changing ratio.
Dependencies are inferred from the claim text.