| 摘要 |
PROBLEM TO BE SOLVED: To stably reduce emission of PM by executing appropriate control based on the distribution state of PM distributed in a cylinder inside space or on a cylinder inside wall surface. SOLUTION: An ECU (electronic control unit) 60 calculates a space distribution coefficient α corresponding to the quantity of PM distributed in the cylinder inside space and a wall surface distribution coefficient β corresponding to the quantity of PM distributed on the cylinder inside wall surface based on at least the operation state of an internal combustion engine. The valve open timing of an exhaust valve 34 is retarded when the space distribution coefficient α is greater than a determination value X. Thus, the after-burn period of PM in which residual oxygen in a cylinder participates is extended, and space PM is reduced. The lift of an exhaust valve 34 is reduced, the flow velocity and the degree of turbulence at discharge of exhaust gas are increased when the wall surface distribution coefficient β is greater than a determination value Y. Then, wall surface PM and residual oxygen are suitably mixed and the reaction properties of both are increased, and the wall surface PM is reduced. COPYRIGHT: (C)2011,JPO&INPIT
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