EXHAUST GAS PURIFICATION APPARATUS , VEHICLE AND METHOD OF CONTROLLING EXHAUST GAS PURIFICATION APPARATUS

An engine exhaust gas purification apparatus 100 includes a catalyst device 51 that contains palladium and rhodium as precious metal and purifies exhaust gas, a linear A/F sensor SW7 provided on an exhaust passage 50 downstream of the catalyst device 51, and a control device 60 that controls a fuel injection valve 18 so as to set the air-fuel ratio of the exhaust gas to a target air-fuel ratio on the basis of the air-fuel ratio detected by the sensor SW7, and the control device 60 determines whether the catalyst device 51 is active and determines whether the catalyst device 51 is deteriorated, and sets the target air-fuel ratio to a first air-fuel ratio on a leaner side when determining that the catalyst device 51 is not active and determining that the catalyst device 51 is deteriorated than when determining that the catalyst device 51 is not deteriorated.