EXHAUST EMISSION CONTROL SYSTEM FOR INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To provide technique capable of preferably continuing a regeneration process of a filter by preventing filter temperature from lowering and preventing the filter temperature from excessively rising in the case where operation state of an internal combustion engine is a slow down operation during the regeneration process of the filter.

SOLUTION: An intake air control means for decreasing intake air quantity by reducing opening of an intake air throttle valve and increasing EGR gas quantity by increasing opening of an EGR valve is provided for an exhaust emission control system for an internal combustion engine for working the intake gas control means in the case where the operation state of the internal combustion engine becomes the slow down operation in which fuel supply is stopped during the regeneration process of the filter. In the exhaust emission control system, during the regeneration process of the filter, the intake gas control means is activated (S106) only in the case that the operation state of the internal combustion engine becomes the slow down operation in which the fuel supply is stopped (S101) and it is determined that the temperature of the filter does not excessively rise even if the intake control means is activated (S104).

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