| 摘要 |
PURPOSE: To perform rapid detection of an excess air ratio by a method wherein based on a detecting intake air amount, an excess air ratio estimated the given number of times beforehand, and an exhaust gas reflux amount, an equivalent intake fresh air amount is estimated and based on the equivalent intake fresh air amount and a fuel feed amount, the excess air ratio of an engine is estimated. CONSTITUTION: In an ECU 8, during operation of an engine 1, a intake air pressure is measured by an intake air pressure sensor 17, and from the intake air pressure, a fuel feed amount, and an engine rotation speed, an intake air amount is calculated. Meanwhile, after an exhaust gas pressure is directly measured by an exhaust pressure sensor or based on other parameter, estimation is effected, from a differential pressure between an exhaust pressure and an intake pressure, and an opening amount of an EGR valve 31 by an EGR position sensor 36, an EGR amount is estimated. From a determined intake air amount and an EGR amount and an excess air ratio a few processes before, an equivalent intake fresh air amount is estimated. From the equivalent intake fresh air amount and a differently detecting fuel feed amount, an excess air ratio is estimated, and according to the excess air ratio, a fuel injection amount is controlled. |
