Patent ID: 7841169
Filing Date: 2010-11-30
Classification: F01N,F02B,Y02T

Abstract:
1. A method for eliminating particulate matter accumulated in an exhaust purification apparatus arranged in an exhaust system of an internal combustion engine, the method comprising: estimating the amount of particulate matter accumulated in the exhaust purification apparatus to obtain an estimated accumulation amount; determining whether the estimated accumulation amount is greater than a reference accumulation amount; starting a normal heating mode for continuously keeping the air-fuel ratio in the exhaust system low by continuously adding fuel to exhaust when the estimated accumulation amount is greater than the reference accumulation amount; determining whether the estimated accumulation amount is less than or equal to a normal burn-up start determination value, which is slightly greater than an end determination value and less than the reference accumulation amount; and changing from the normal heating mode to a burn-up heating mode for intermittently lowering the air-fuel ratio in the exhaust system by intermittently adding fuel to the exhaust when the estimated accumulation amount within a mode change range set in accordance with a state in which a great part of the accumulated particulate matter is eliminated from the exhaust purification apparatus and is less than or equal to the normal burn-up start determination value so that a temperature of a catalyst bed is elevated so that the temperature of the catalyst bed is higher in the burn-up heating mode than in the normal heating mode.