Patent ID: 7246485
Filing Date: 2007-07-24
Classification: F01N,F02B,F02D,F02M,Y02T

Abstract:
1. An exhaust gas purifying device for an internal combustion engine, comprising: a filter carrying a NOx absorbent thereon and capable of temporarily capturing fine particles contained in an exhaust gas of the internal combustion engine and of removing the fine particles by oxidation in a prescribed temperature range, the NOx absorbent functioning to absorb NOx contained in the exhaust gas when the exhaust gas flowing into the NOx absorbent exhibits a lean air-fuel ratio and to discharge the absorbed NOx when the exhaust gas flowing into the NOx absorbent exhibits one of a theoretical air-fuel ratio and a rich air-fuel ratio; and a controller that: the heat-up control is executed by at least one of low-temperature combustion, post-injection, VIGOM-injection, and addition of fuel to an exhaust system according to an operational state of the internal combustion engine, the heat-up control for removing the fine particles by oxidation is executed by at least one of the low-temperature combustion, the post-injection, the VIGOM-injection, and the addition of fuel to the exhaust system, and the heat-up control for recovery from sulfur poisoning is executed by a combination of the low-temperature combustion and the addition of fuel to the exhaust system, and in the heat-up control for removing the fine particles by oxidation, at least the low-temperature combustion is conducted when a coolant temperature of the internal combustion engine is equal to or higher than a predetermined value, and at least the post-injection is conducted when the coolant temperature of the internal combustion engine is less than the predetermined value.