| 摘要 |
PROBLEM TO BE SOLVED: To enhance an exhaust cleaning performance only by using a three way catalyst without requiring a lean NOx catalyst while possessing an improvement effect of fuel consumption by lean combustion. SOLUTION: In the multi-cylinder spark ignition type engine, burned gas exhausted from leading cylinders 2A, 2D at an exhaust stroke side between a pair of cylinders in which an exhaust stroke and a suction stroke are overlapped is introduced to the following cylinders 2B, 2C at the suction stroke side through a gas passage 22 between the cylinders as such at a low load/low rotation area. Only the gas exhausted from the following cylinders 2B, 2C is introduced to an exhaust passage 20 provided with the three way catalyst 24. Combustion is carried out in the leading cylinders 2A, 2D in the state that a lean air/fuel ratio is larger than a theoretical air/fuel ratio by a predetermined amount. A feed of the fuel to the respective cylinders is controlled such that the combustion is carried out in the following cylinders 2B, 2C in the state that the fuel is fed to the burned gas of the lean air/fuel ratio introduced from the leading cylinders 2A, 2D to make the theoretical air/fuel ratio. COPYRIGHT: (C)2003,JPO |
