Exhaust purification system of internal combustion engine

摘要

An exhaust purification system of an internal combustion engine of the present invention comprises a silver-alumina-based catalyst device arranged in the engine exhaust system. When a temperature of the silver-alumina-based catalyst device becomes a second set temperature T2 lower than a first set temperature T1 at which the silver-alumina-based catalyst device releases NO2, and releases NO, the silver-alumina-based catalyst device is heated such that a temperature elevation rate thereof is increased to make the temperature T of the silver-alumina-based catalyst device be a third set temperature T3 between the first set temperature T1 and the second set temperature T2.

主权项

1. An exhaust purification system of an internal combustion engine, comprising:
a silver-alumina-based catalyst device arranged in an engine exhaust system; a temperature estimating device configured to estimate a temperature of the silver-alumina-based catalyst device; a heating device configured to heat the silver-alumina-based catalyst device; and an electronic control unit operating the heating device so as to heat the silver-alumina-based catalyst device; wherein a first set temperature at which said silver-alumina-based catalyst device releases NO2 and a second set temperature at which said silver-alumina-based catalyst device releases NO are set in the electronic control unit, the second set temperature being lower than the first set temperature; and wherein the exhaust purification system is configured such that when a temperature of said silver-alumina-based catalyst device becomes the second set temperature, said silver-alumina-based catalyst device is heated by the heating device such that a temperature elevation rate thereof is increased to make the temperature of said silver-alumina-based catalyst device be a third set temperature between said first set temperature and said second set temperature.