| 摘要 |
PROBLEM TO BE SOLVED: To provide an air-fuel ratio control device for an internal combustion engine, capable of effectively restricting evaporation of fuel due to lowering of fuel pressure, and precisely controlling an air-fuel ratio to a target air-fuel ratio. SOLUTION: A feedback correction coefficient KAF for fuel injection quantity is compared with a learned value KAFREF to detect vaporization of fuel. Based on the result of detection, action of a fuel pump is controlled to raise fuel pressure for restricting vaporization of fuel. When fuel pressure is so low as to possibly generate vapor, and make the air-fuel ratio lean, the fuel pressure is once raised, and then the feedback correction coefficient KAF is learned, so that the leaned value KAFREF is correctly obtained (S40-S54). COPYRIGHT: (C)2006,JPO&NCIPI
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