Working machine, degradation detection device for oxidation catalyst, degradation detection method for oxidation catalyst, and degradation detection program for oxidation catalyst

An oxidation catalyst degradation detection device for an exhaust gas aftertreatment apparatus having a filter for collecting a particle from exhaust gas of an engine and an oxidation catalyst provided upstream of the filter for oxidizing unburnt fuel, the oxidation catalyst degradation detection device detecting degradation of the oxidation catalyst, comprising:

• a temperature detecting device for detecting a temperature between the oxidation catalyst and the filter;
• and
• a controller, wherein
• the controller
• executes a regeneration processing of heating the filter to burn the particle accumulated on the filter,
• calculates an average of temperatures detected by the temperature detecting device in the regeneration processing;
• calculates a degradation degree of the oxidation catalyst on the basis of the average,
• determines whether the regeneration processing is executed a first number of times or more in a first period and the average is higher than a first temperature and lower than a second temperature, and
• determines whether the regeneration processing is executed a second number of times or more that is larger than the first number of times in a second period not shorter than the first period and the average is lower than a third temperature not higher than the first temperature.

An oxidation catalyst degradation detection method for an exhaust gas aftertreatment apparatus having a filter for collecting a particle from exhaust gas of an engine and an oxidation catalyst provided upstream of the filter for oxidizing unburnt fuel, the oxidation catalyst degradation detection method detecting degradation of the oxidation catalyst, comprising:

• a regeneration processing step of executing a regeneration processing of heating the filter to burn the particle accumulated on the filter;
• a temperature detection step of detecting a temperature between the oxidation catalyst and the filter;
• an average calculation step of calculating an average of temperatures detected in the temperature detection step in the regeneration processing;
• a degradation degree calculation step of calculating a degradation degree of the oxidation catalyst on the basis of the average calculated in the average calculation step,
• a step of determining whether the regeneration processing is executed a first number of times or more in a first period and the average is higher than a first temperature and lower than a second temperature, and
• a step of determining whether the regeneration processing is executed a second number of times or more that is larger than the first number of times in a second period not shorter than the first period and the average is lower than a third temperature not higher than the first temperature.

A non-transitory computer readable recording medium storing an oxidation catalyst degradation detection program for an exhaust gas aftertreatment apparatus having a filter for collecting a particle from exhaust gas of an engine and an oxidation catalyst provided upstream of the filter for oxidizing unburnt fuel, the oxidation catalyst degradation detection program causing a computer to detect degradation of the oxidation catalyst by causing the computer to execute:

• a regeneration processing step of executing a regeneration processing of heating the filter to burn the particle accumulated on the filter;
• a temperature detection step of detecting a temperature between the oxidation catalyst and the filter;
• an average calculation step of calculating an average of temperatures detected in the temperature detection step in the regeneration processing;
• a degradation degree calculation step of calculating a degradation degree of the oxidation catalyst on the basis of the average calculated in the average calculation step,
• a step of determining whether the regeneration processing is executed a first number of times or more in a first period and the average is higher than a first temperature and lower than a second temperature, and
• a step of determining whether the regeneration processing is executed a second number of times or more that is larger than the first number of times in a second period not shorter than the first period and the average is lower than a third temperature not higher than the first temperature.