| 摘要 |
PROBLEM TO BE SOLVED: To provide a spark ignition type direct injection engine having a turbo supercharger, capable of promoting the activation of an exhaust emission control catalyst downstream from a turbine at cold start. SOLUTION: In the preceding term of catalyst activation, in which an engine is not yet warmed up at cold start, fuel injection is performed separately in an air intake process and in a compression process, and an ignition timing is retarded for a predetermined period after MBT, to elevate the temperature of the engine or an exhaust gas, while in the subsequent term of catalyst activation in which the engine is warmed up to a certain degree, retardation of ignition timing is released, and the fuel is injected separately in the compression process and an in an expansion process. Thereby, the temperature of exhaust gas is elevated by the combustion heat of the fuel injected in the expansion process, and also the heat generated due to the oxidation of unburned HC by turbine agitation for elevating the temperature or the activation of the exhaust emission control catalyst downstream from the turbine is promoted. |
