Engine Control Unit

Abstract

To solve a problem that abnormal diagnosis of an air-fuel ratio sensor becomes hard to be executed in a state that a catalyst temperature is low.SOLUTION: An engine control device 10 calculates a first catalyst temperature by using a measurement value of an air-fuel ratio by a front air-fuel ratio sensor 26 and calculates a second catalyst temperature by using a calculation value of the air-fuel ratio calculated from amounts of intake air and a fuel supplied for combustion in a combustion chamber 12. The engine control device 10 determines presence or absence of establishment of execution conditions of abnormality diagnosis of the front air-fuel ratio sensor 26 by using the second catalyst temperature of them.SELECTED DRAWING: Figure 1