Control device for internal combustion engine

An apparatus comprising:

• an engine body;
• and
• an exhaust after-treatment system installed in an exhaust passage of the engine body;
• and
• circuitry configured to:
• calculate a temperature of exhaust flowing into the exhaust after-treatment system as a first exhaust temperature;
• calculate a temperature of exhaust flowing out from the exhaust after-treatment system as a second exhaust temperature;
• calculate a rate of change over time of the first exhaust temperature and a rate of change over time of the second exhaust temperature;
• judge if the exhaust after-treatment system is in a removed state removed from the exhaust passage based on a ratio between the rate of change over time of the first exhaust temperature and the rate of change over time of the second exhaust temperature;
• and
• when a predetermined condition stands, judge if the exhaust after-treatment system is in the removed state, wherein
• the predetermined condition includes a time derivative of the rate of change over time of the first exhaust temperature falling within a predetermined range including zero at a transition time when a flow rate of intake air of the engine body becomes a predetermined flow rate or more.

An apparatus comprising:

• an engine body;
• an exhaust after-treatment system installed in an exhaust passage of the engine body;
• and
• circuitry configured to:
• calculate a temperature of exhaust flowing into the exhaust after-treatment system as a first exhaust temperature;
• calculate a temperature of exhaust flowing out from the exhaust after-treatment system as a second exhaust temperature;
• calculate a rate of change over time of the first exhaust temperature and a rate of change over time of the second exhaust temperature;
• judge if the exhaust after-treatment system is in a removed state removed from the exhaust passage based on a ratio between the rate of change over time of the first exhaust temperature and the rate of change over time of the second exhaust temperature;
• and
• judge a state is not the removed state if an integrated value, which is obtained by integrating a certain number or more of values of the ratio, is greater than or equal to a predetermined threshold value.

An apparatus comprising:

• an engine body;
• an exhaust after-treatment system installed in an exhaust passage of the engine body;
• and
• circuitry configured to:
• calculate a temperature of exhaust flowing into the exhaust after-treatment system as a first exhaust temperature;
• calculate a temperature of exhaust flowing out from the exhaust after-treatment system as a second exhaust temperature;
• calculate a rate of change over time of the first exhaust temperature and a rate of change over time of the second exhaust temperature;
• judge if the exhaust after-treatment system is in a removed state removed from the exhaust passage based on a ratio between the rate of change over time of the first exhaust temperature and the rate of change over time of the second exhaust temperature;
• and
• judge a state is a normal state where the exhaust after-treatment system is not removed from the exhaust passage if an integrated value, which is obtained by integrating a certain number or more of values of the ratio, is greater than or equal to a predetermined threshold value.

An apparatus comprising:

• an engine body;
• and
• an exhaust after-treatment system installed in an exhaust passage of the engine body;
• and
• circuitry configured to:
• calculate a temperature of exhaust flowing into the exhaust after-treatment system as a first exhaust temperature;
• calculate a temperature of exhaust flowing out from the exhaust after-treatment system as a second exhaust temperature;
• calculate a rate of change over time of the first exhaust temperature and a rate of change over time of the second exhaust temperature;
• calculate an integrated value which is obtained by integrating a certain number or more of values of a ratio between the rate of change over time of the first exhaust temperature and the rate of change over time of the second exhaust temperature;
• judge if the exhaust after-treatment system is in a removed state removed from the exhaust passage or a normal state where the exhaust after-treatment system is not removed from the exhaust passage based on the integrated value;
• and
• judge that a state is the removed state if the integrated value is less than a predetermined threshold value.