| 摘要 |
<P>PROBLEM TO BE SOLVED: To accurately specify a factor causing imbalance in air-fuel ratio between cylinders in a multi-cylinder type internal combustion engine equipped with an EGR device. <P>SOLUTION: An engine 10 has cylinders 11-14 respectively connected to branch pipes 21-24 branched from a main pipe 20 as an intake manifold 16. Fuel injection valves 71-74 are attached to the branch pipes 21-24. Further, the branch pipes 21-24 are connected to branch pipes 61-64 branched from an EGR pipe 52 on a downstream side of the EGR valve 56, and exhaust gas introduced from the EGR valve 56 is fed to each of the branch pipes 21-24. An ECU 1000 detects imbalance of air-fuel ratio among cylinders based on cylinder-by-cylinder air-fuel ratio detected by air-fuel ratio sensors 81-84 provided in branch pipes 31-34 as an exhaust manifold 18. If there is an imbalance in air-fuel ratio among cylinders, the EGR valve 56 is closed, and thereafter, imbalance in air-fuel ratio among cylinders is detected again. <P>COPYRIGHT: (C)2009,JPO&INPIT |
