| 摘要 |
<p>PROBLEM TO BE SOLVED: To secure the exhaust purifying performance and the heat resisting reliability of catalyst 32 and 34, preventing deterioration of the driving feel by elaborately controlling the condition of the air/fuel ratio of exhaust when an engine 1 with a three-way catalyst 32 and lean NOx catalyst 34 disposed in an exhaust pathway 28 is moved from a stratified charge combustion region (a) or a uniformed lean region (c) to aλ=1 region (b) between them in controlling the exhaust by changing the region so that the internal cylinder air/fuel ratio is lean in the stratified charge combustion region (a) on the low rotation/ low load side and in the uniformed lean region (c) on the higher rotation side, or so that the internal cylinder air/fuel ratio is nearly the theoretical air/fuel ratio in theλ=1 region (b) between the regions (a) and (c). SOLUTION: When the engine 1 is moved from the stratified charge combustion region (a) to theλ=1 region (b) (SA14), the quantity of fuel injected by injector 12 is increased/corrected to enrich the internal cylinder air/fuel ratio, so that the condition of the air/fuel ratio of exhaust is enriched. When the engine 1 is moved from the uniformed lean region (c) to theλ=1 region (b), the enriching correction mentioned above will not be executed basically.</p> |
