US 8,806,928 B2 · Catalyst deterioration detection apparatus and catalyst deterioration detection method for internal combustion engine

Abstract

Provision is made for a catalyst that is arranged in an exhaust passage of an internal combustion engine and has an oxidation function, downstream side temperature detection means that detects the temperature of an exhaust gas at a downstream side from the catalyst, and addition means that adds a reducing agent into the exhaust gas from an upstream side from the catalyst, wherein there are also provided correlation value calculation means that calculates a correlation value which is correlated with an amount of change of the temperature detected by the downstream side temperature detection means when the reducing agent is added by the addition means and when a transient operation of the internal combustion engine is carried out, and determination means that determines a deterioration of the catalyst by making a comparison between the correlation value and a threshold value which indicates the deterioration of the catalyst.

Claims14

Dependent claims

A catalyst deterioration detection apparatus for an internal combustion engine comprising:

a catalyst that is arranged in an exhaust passage of the internal combustion engine and has an oxidation function;
downstream side temperature sensor that detects a temperature of an exhaust gas at a downstream side from said catalyst;
and
addition unit that adds a reducing agent into the exhaust gas from an upstream side from said catalyst;
comprising:
an electronic control unit that includes program logic which, calculates a range of drop of a temperature detected by said downstream side temperature sensor during deceleration of said internal combustion engine or a range of rise of a temperature detected by said downstream side temperature sensor during acceleration of said internal combustion engine, when the reducing agent is added by said addition unit;
and
determines a deterioration of said catalyst by making a comparison between said range of temperature drop or said range of temperature rise and a threshold value which indicates the deterioration of said catalyst.

5 more elements

A catalyst deterioration detection method for an internal combustion engine, wherein

a first step to calculate a range of drop of a temperature of an exhaust gas at a downstream side from a catalyst during deceleration of said internal combustion engine or a range of rise of a temperature of the exhaust gas at the downstream side from said catalyst during acceleration of said internal combustion engine, during the time when a reducing agent is added into the exhaust gas from an upstream side from said catalyst which has an oxidation function and is arranged in the exhaust passage of the internal combustion engine;
and
a second step to determine a deterioration of said catalyst by comparing said range of drop or said range of rise with a threshold value which indicates the deterioration of said catalyst.

Dependencies are inferred from the claim text.

Catalyst deterioration detection apparatus and catalyst deterioration detection method for internal combustion engine

Life of this patent

Catalyst deterioration detection apparatus and catalyst deterioration detection method for internal combustion engine

Life of this patent

Abstract

Claims14