The diesel particulate filter (DPF) that collects PM in diesel exhaust requires a regeneration process that burns and removes PM to prevent clogging. At this process, since the DPF is brought to a high temperature state by the fuel increase, there is concern about deterioration of fuel consumption and thermal degradation of the rear-stage SCR catalyst. In this study, we investigated the regeneration frequency during actual road driving, the behavior of exhaust gas during regeneration, and the fuel increase. Furthermore, to study the thermal degradation of the SCR catalyst, the amount of heat added to the catalyst was estimated.