| 摘要 |
<p>PURPOSE: To conduct correct closed loop control of an air/fuel ratio for an engine while supporting indication of deterioration of a catalyst by applying a complementary filter set that combines sensor outputs of a single exhaust gas oxygen EGO from a plurality of sensors arranged in the upstream and downstream sides of the catalyst. CONSTITUTION: Sensors 21, 22 of a first and a second exhaust gas oxygen EGO are respectively positioned in the upstream and downstream sides of a catalyst 20 arranged in an engine 23. Each output of the exhaust gas oxygen sensors 21, 22 is respectively input into a complementary filter set 24 that is composed of a high pass filter and a low pass filter. Furthermore, the combined output of the high pass filter and the low pass filter is output to an air/fuel ratio feedback controller 25. A fuel measuring system 26 is controlled by the output of the air/fuel ratio feedback controller 25 and the engine 23 is in turn controlled. By this manner, correct closed loop control of the air/fuel ratio of the engine 23 is realized and deterioration degree of the catalyst 20 can be indicated.</p> |
