Patent ID: 8091347
Filing Date: 2012-01-10
Classification: F01N,F02B,F02D,Y02T

Abstract:
1. An exhaust gas purification apparatus comprising: a particulate filter capable of collecting particulate matter in exhaust of an internal combustion engine and being restored by removing the particulate matter by oxidation when a temperature of the exhaust reaches a restoration operable temperature; an intake air amount reducing means provided in an air intake system of the internal combustion engine and capable of reducing an intake air amount; an exhaust heating means provided in an exhaust system of the internal combustion engine and capable of heating exhaust gas; an accumulation amount detecting means capable of detecting that an accumulation amount of particulate matter in the particulate filter exceeds a predetermined amount; an exhaust temperature detecting means capable of detecting the exhaust temperature of the internal combustion engine; and a restoration operation control means for receiving outputs of the accumulation amount detecting means and the exhaust temperature detecting means, and executing any one of an intake air amount reducing operation by the intake air amount reducing means and an exhaust gas heating operation by the exhaust heating means with priority or executing both the intake air amount reducing operation and the exhaust gas heating operation simultaneously, when the accumulation amount of particulate matter in the particulate filter exceeds the predetermined amount and the exhaust temperature of the internal combustion engine is lower than the restoration operable temperature, wherein the restoration operation control means executes any one of the intake air amount reducing operation by the intake air amount reducing means and the exhaust gas heating operation by the exhaust heating means with priority when the accumulation amount of particulate matter in the particulate filter exceeds the predetermined amount and the exhaust temperature of the internal combustion engine is lower than the restoration operable temperature, and thereafter, executes the other operation when the exhaust temperature of the internal combustion engine has not reached the restoration operable temperature, a plurality of predetermined threshold values are previously set for an intake air reduction amount by the intake air amount reducing means, as the plurality of threshold values, a first threshold value corresponding to an intake air reduction amount when a CO and THC concentration of exhaust gas reaches a tolerance limit, and a second threshold value corresponding to an intake air reduction amount when the internal combustion engine reaches a run limit due to misfire, are set, and when the intake air reduction amount reaches the first threshold value during the intake air amount reducing operation by the intake air amount reducing means, the intake air amount reducing operation by the intake air amount reducing means is switched to the exhaust gas heating operation by the exhaust heating means, and thereafter, when the exhaust temperature of the interns combustion engine still does not reach the restoration operable temperature, the intake air amount reducing operation bathe intake air amount reducing means is resumed with the second threshold value being a limit of the intake air reduction amount.