US 2009/0288397 A1 · EXHAUST GAS PURIFICATION DEVICE OF INTERNAL COMBUSTION ENGINE

Abstract

An SCR catalyst is provided in an exhaust pipe of an engine and a urea solution addition valve is provided upstream of the SCR catalyst in the exhaust pipe. An ECU controls urea solution addition quantity of the urea solution addition valve based on ammonia adsorption quantity to the SCR catalyst. The ECU calculates the ammonia adsorption quantity in the SCR catalyst based on time-series data of an ammonia balance between ammonia supply to the SCR catalyst accompanying the urea solution addition of the urea solution addition valve and ammonia consumption in the SCR catalyst. The ECU calculates NOx quantity introduced into the SCR catalyst or a parameter correlated with the NOx quantity and performs initialization of the ammonia adsorption quantity at timing decided based on a result of the calculation.

Claims19

Dependent claims

An exhaust gas purification device of an internal combustion engine applied to an exhaust gas purification system that has a NOx catalyst provided in an exhaust passage of the internal combustion engine for adsorbing a reducing agent and for selectively purifying NOx in exhaust gas with the reducing agent and that adds the reducing agent with a reducing agent adding means upstream of the NOx catalyst with respect to a flow direction of the exhaust gas, the exhaust gas purification device comprising:

an adsorption quantity calculating means for calculating reducing agent adsorption quantity in the NOx catalyst based on time-series data of a balance between supply of the reducing agent to the NOx catalyst accompanying the addition of the reducing agent by the reducing agent adding means and consumption of the reducing agent due to a reduction reaction in the NOx catalyst;
a NOx quantity calculating means for calculating NOx quantity introduced into the NOx catalyst or a parameter correlated with the NOx quantity;
and
an initialization performing means for performing initialization of the reducing agent adsorption quantity at timing decided based on a calculation result of the NOx quantity calculating means.

1 more element

an adsorption quantity calculating means for calculating reducing agent adsorption quantity in the NOx catalyst based on time-series data of a balance between supply of the reducing agent to the NOx catalyst accompanying the addition of the reducing agent by the reducing agent adding means and consumption of the reducing agent due to a reduction reaction in the NOx catalyst;
a purification rate calculating means for calculating an actual NOx purification rate of the NOx catalyst;
an initialization performing means for performing initialization of the reducing agent adsorption quantity according to the actual NOx purification rate, which is calculated by the purification rate calculating means, based on a predetermined relationship between the reducing agent adsorption quantity and the NOx purification rate;
and
a properness determining means for determining whether the NOx purification rate calculated by the purification rate calculating means is a proper value to be used for the initialization, wherein
the exhaust gas purification device permits the initialization by the initialization performing means on a condition that the properness determining means determines that the NOx purification rate is proper.

3 more elements

Dependencies are inferred from the claim text.

Exhaust gas purification device of internal combustion engine

Life of this patent

Exhaust gas purification device of internal combustion engine

Life of this patent

Abstract

Claims19