Patent ID: 7877985
Filing Date: 2011-02-01
Classification: F01N,F02B,F02D,Y02T

Abstract:
1. An exhaust gas purification system for an internal combustion engine comprising: a particulate filter for trapping particulate matter contained in exhaust gas; an exhaust throttle valve provided in an exhaust passage downstream of said particulate filter; a PM filter regeneration device that performs a PM filter regeneration process for oxidizing and removing particulate matter trapped on said particulate filter; a pressure increasing device for increasing the pressure inside the particulate filter by decreasing the degree of opening of said exhaust throttle valve when said PM filter regeneration process is performed; a prediction device for making a prediction as to whether or not there is a possibility that the temperature of said particulate filter reaches an upper limit value, when the pressure inside said particulate filter has been increased by said pressure increasing device; a determining device that, when the pressure inside said particulate filter is increased by said pressure increasing device, determines that the possibility that the temperature of said particulate filter rises excessively becomes high when an inflowing exhaust gas quantity is excessively small, when the temperature of said particulate filter is close to the upper limit value, when a remaining PM amount is excessively large, or when an engine load is excessively high; and a pressure decreasing device that, when it is determined by said determining device that the possibility of an excessive temperature rise of said particulate filter is high, stops said PM filter regeneration process by immediately adjusting the degree of opening of said exhaust throttle valve back to a normal degree of opening and that, when it is determined by said determining device that the possibility of an excessive temperature rise of said particulate filter is not high, continues said PM filter regeneration process by decreasing the pressure inside said particulate filter when it is predicted by said prediction device that there is a possibility that the temperature of said particulate filter reaches the upper limit value.