CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

A degree of deterioration of oil is obtained from a soot concentration in engine oil. From the degree of deterioration of oil, an allowable upper limit value of compressor outlet temperature is obtained (Step ST1). An allowable upper limit supercharging pressure corresponding to the allowable upper limit value of compressor outlet temperature is calculated. A target supercharging pressure obtained from an engine operating state is compared with the allowable upper limit supercharging pressure. If the target supercharging pressure is equal to or less than the allowable upper limit supercharging pressure, a turbocharger is controlled setting the target supercharging pressure as a control supercharging pressure. If the target supercharging pressure exceeds the allowable upper limit supercharging pressure, the turbocharger is controlled setting the allowable upper limit supercharging pressure as the control supercharging pressure. Additionally, an EGR valve is controlled so that an EGR rate is not separated from a target EGR rate (Step ST5).