Control apparatus for internal combustion engine

A control apparatus for an internal combustion engine, comprising:

• intake air amount control means for controlling an intake air amount of the internal combustion engine;
• ignition timing control means for controlling an ignition timing of the internal combustion engine;
• catalyst heat-up control means for increasing the intake air amount after cold start of the internal combustion engine and performing control for retarding the ignition timing;
• air-fuel ratio detecting means for detecting an air-fuel ratio of exhaust gas in the internal combustion engine;
• and
• fuel property determining means for making a determination on fuel property through a comparison between a parameter value calculated from the air-fuel ratio and a preset reference value when the catalyst heat-up control means performs the control for retarding the ignition timing,
• further comprising:
• average air-fuel ratio calculating means for calculating an average of the air-fuel ratio immediately before start of the control for retarding the ignition timing through the catalyst heat-up control means to output an average air-fuel ratio;
• and
• a second air-fuel ratio difference integrating means for integrating a difference between the air-fuel ratio and the average air-fuel ratio until a predetermined time elapses since start of the control for retarding the ignition timing through the catalyst heat-up control means,
• wherein the fuel property determining means uses an integrated value of a second air-fuel ratio difference, which has been integrated by the second air-fuel ratio difference integrating means, as the parameter value.

A control apparatus for an internal combustion engine, comprising:

• intake air amount control means for controlling an intake air amount of the internal combustion engine;
• ignition timing control means for controlling an ignition timing of the internal combustion engine;
• catalyst heat-up control means for increasing the intake air amount after cold start of the internal combustion engine and performing control for retarding the ignition timing;
• air-fuel ratio detecting means for detecting an air-fuel ratio of exhaust gas in the internal combustion engine;
• and
• fuel property determining means for making a determination on fuel property through a comparison between a parameter value calculated from the air-fuel ratio and a preset reference value when the catalyst heat-up control means performs the control for retarding the ignition timing,
• further comprising:
• air-fuel ratio feedback correction means for outputting an air-fuel ratio feedback correction amount for correcting a fuel injection amount such that the air-fuel ratio coincides with a target air-fuel ratio;
• and
• air-fuel ratio feedback correction amount integrating means for integrating the air-fuel ratio feedback correction amount until a predetermined time elapses since start of the control for retarding the ignition timing through the catalyst heat-up control means,
• wherein the fuel property determining means uses an integrated value of an air-fuel ratio feedback correction amount, which has been integrated by the air-fuel ratio feedback correction amount integrating means, as the parameter value.