| 摘要 |
<p>A technique is provided which is capable of suppressing the adhesion of fuel added from fuel addition valves to exhaust passages, and at the same time suppressing the fuel from slipping through exhaust gas purification devices. Timing of the addition of fuel at which fuel is added from the fuel addition valves 11, 12 is switched over into a period in which instantaneous exhaust gas flow rates in the exhaust passages are different from each other, in accordance with an engine operating condition. As a result, in case where the operating condition has a high possibility of fuel adhering to the exhaust pipes 7, 8, fuel is added at the time when the instantaneous exhaust gas flow rates in the exhaust pipes 7, 8 are high, so that the fuel can be easily carried to the vicinity of the exhaust gas purification devices 9, 10, while being entrained in the exhaust gas, thereby suppressing the fuel from adhering to the exhaust pipes 7, 8. In addition, in case where the operating condition has a high possibility of fuel slipping through the exhaust gas purification devices 9, 10, fuel is added at the time when the instantaneous exhaust gas flow rates in the exhaust pipes 7, 8 are low, so that the fuel can not be easily entrained in the exhaust gas to make the movement of the fuel slow, thereby suppressing the fuel from slipping through the exhaust gas purification devices 9, 10.</p> |
