| 摘要 |
PROBLEM TO BE SOLVED: To detect NOx catalyst having a temperature equal to or above an activation temperature without depending on a temperature sensor, so that NOx purge is efficiently performed when in rich operation.SOLUTION: A traveling motor 40 is driven by the generated output by a generator 20 driven by an engine 10 and a battery 30. During the performance of purge, the engine 10 is shifted from lean operation to rich operation. Subject to generation of power under a state of lean operation having been continued for a predetermined period or more, a switch-over to rich operation is allowed. |
