Abstract: The occurrence of the misfire having a level at which exhaust purifying function of a catalyst is impaired (OT-level misfire) is detected. Upon the detection of the OT-level misfire, basic OT risk from the misfire is multiplied by a correction coefficient corresponding to the accumulated PM amount on the catalyst. The basic OT risk from the misfire is a basic value of OT risk from the misfire which is set based on the operating condition of the engine. The correction coefficient is set to a smaller value as the accumulated PM amount increases. Therefore, the OT risk from the misfire after the multiplication decreases as the accumulated PM amount increases. When a predetermined judgement condition with the OT risk from the misfire is established, it is judged that the misfire having the level occurs.

Abstract: The occurrence of the misfire having a level at which exhaust purifying function of a catalyst is impaired (OT-level misfire) is detected. Upon the detection of the OT-level misfire, basic OT risk from the misfire is multiplied by a correction coefficient corresponding to the accumulated PM amount on the catalyst. The basic OT risk from the misfire is a basic value of OT risk from the misfire which is set based on the operating condition of the engine. The correction coefficient is set to a smaller value as the accumulated PM amount increases. Therefore, the OT risk from the misfire after the multiplication decreases as the accumulated PM amount increases. When a predetermined judgement condition with the OT risk from the misfire is established, it is judged that the misfire having the level occurs.

Abstract: The occurrence of the misfire having a level at which exhaust purifying function of a catalyst is impaired (OT-level misfire) is detected. Upon the detection of the OT-level misfire, basic OT risk from the misfire is multiplied by a correction coefficient corresponding to the accumulated PM amount on the catalyst. The basic OT risk from the misfire is a basic value of OT risk from the misfire which is set based on the operating condition of the engine. The correction coefficient is set to a smaller value as the accumulated PM amount increases. Therefore, the OT risk from the misfire after the multiplication decreases as the accumulated PM amount increases. When a predetermined judgement condition with the OT risk from the misfire is established, it is judged that the misfire having the level occurs.

Abstract: The occurrence of the misfire having a level at which exhaust purifying function of a catalyst is impaired (OT-level misfire) is detected. Upon the detection of the OT-level misfire, basic OT risk from the misfire is multiplied by a correction coefficient corresponding to the accumulated PM amount on the catalyst. The basic OT risk from the misfire is a basic value of OT risk from the misfire which is set based on the operating condition of the engine. The correction coefficient is set to a smaller value as the accumulated PM amount increases. Therefore, the OT risk from the misfire after the multiplication decreases as the accumulated PM amount increases. When a predetermined judgement condition with the OT risk from the misfire is established, it is judged that the misfire having the level occurs.

Abstract: The occurrence of the misfire having a level at which exhaust purifying function of a catalyst is impaired (OT-level misfire) is detected. Upon the detection of the OT-level misfire, basic OT risk from the misfire is multiplied by a correction coefficient corresponding to the accumulated PM amount on the catalyst. The basic OT risk from the misfire is a basic value of OT risk from the misfire which is set based on the operating condition of the engine. The correction coefficient is set to a smaller value as the accumulated PM amount increases. Therefore, the OT risk from the misfire after the multiplication decreases as the accumulated PM amount increases. When a predetermined judgement condition with the OT risk from the misfire is established, it is judged that the misfire having the level occurs.

Abstract: An electric locomotive has two AC-DC converters which are connected in cascade, and a power factor controller is connected to one of the converters. Two automatic pulse phase shifters are provided for the two converters and controlled by a signal responding to a difference signal between a current flowing in the converters and a reference signal. One of the input signals of the automatic pulse phase shifter is regulated by a bias signal. The output from each of the automatic pulse phase shifters to each of the converters is switched when the measured speed of the locomotive exceeds a predetermined reference speed signal.