Fuel property determination apparatus for internal combustion engine

A fuel property determination apparatus for an internal combustion engine, the apparatus comprising:

• a fuel injection valve for injecting fuel into a cylinder;
• a first injection execution device for executing fuel injection using the fuel injection valve at a first injection timing during an expansion stroke;
• a second injection execution device for executing fuel injection using the fuel injection valve at at least one second injection timing during the expansion stroke, the second injection timing being retarded from the first injection timing, while a combustion cycle proceeds unlike that when the fuel injection at the first injection timing is performed;
• a combustion pressure acquisition device for detecting or estimating a combustion pressure or a correlation value thereof;
• an air-fuel ratio acquisition device for acquiring an air-fuel ratio of an exhaust gas;
• and
• a fuel property determination device for determining a fuel property based on a combustion pressure during combustion each associated with the fuel injection at the first injection timing and the second injection timing or a correlation value thereof, and an air-fuel ratio of an exhaust gas during combustion each associated with the fuel injection at the first injection timing and the second injection timing.