Exhaust purification device of internal combustion engine

An exhaust purification system of an internal combustion engine, comprising:

• an exhaust purification device;
• a sulfur trap device arranged upstream of the exhaust purification device;
• and
• an electronic control unit that includes control logic, which when executed:
• integrates an amount of SOX passing through the sulfur trap device into a current integrated value;
• sets a corresponding allowance value of the current integrated value for each elapsed period;
• determines whether the current integrated value exceeds the corresponding allowance value;
• determines whether fuel has been supplied into a fuel tank between a first set period and a current time;
• and
• determines whether engine oil has been exchanged between the first set period and the current time, wherein
• when the electronic control unit determines that the current integrated value exceeds the corresponding allowance value, and the electronic control unit determines that fuel has been supplied into the fuel tank and engine oil has not been exchanged between the first set period and the current time, then the electronic control unit makes the determination that fuel with a high concentration of sulfur has been supplied into the fuel tank.