| 摘要 |
An actual intake air quantity at the time when the intake air quantity is changed compulsorily with an EGR valve is measured with an airflow meter. An oxygen concentration of exhaust gas after combustion in a diesel engine is estimated based on the measured actual intake air quantity and a fuel injection quantity of the diesel engine. The estimated oxygen concentration is compared with an actual oxygen concentration sensed with an A/F sensor, thereby sensing response of the A/F sensor. Even if a response time for causing a change in the intake air quantity with the EGR valve changes, the change of the response time does not affect the estimate of the oxygen concentration since the oxygen concentration is estimated based on the actual intake air quantity. Therefore, the response of the A/F sensor can be sensed with high accuracy. |
