Exhaust gas purification apparatus for internal combustion engine
AssigneeToyota Jidosha Kabushiki Kaisha
InventorYuki Bisaiji
Life of this patent
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Abstract
A NOx storing and reducing catalyst is disposed in an engine exhaust gas passage in which the catalyst stores NOx contained in the inflow exhaust gas when an air-fuel ratio of inflow exhaust gas is lean and releases and reduces the stored NOx when the air-fuel ratio of the inflow exhaust gas is rich. A stored NOx amount of the NOx storing and reducing catalyst is calculated and an exhaust gas purification operation is controlled based on the stored NOx amount. When the air-fuel ratio of inflow exhaust gas is lean, a ratio of NOx components in the inflow exhaust gas is calculated. An increment of the stored NOx amount per unit time is calculated based on the ratio of NOx components.
Claims8
An exhaust gas purification device for an internal combustion engine having an exhaust gas passage, comprising:
- a NOx storing and reducing catalyst that is disposed in the exhaust gas passage and that stores NOx contained in inflow exhaust gas when an air-fuel ratio of the inflow exhaust gas is lean and releases and reduces the stored NOx when the air-fuel ratio of the inflow exhaust gas becomes rich;
- a stored NOx amount calculator for calculating a stored NOx amount of the NOx storing and reducing catalyst;
- and
- a controller for controlling an exhaust gas purification operation based on said calculated stored NOx amount,
- wherein:
- when the air-fuel ratio of the inflow exhaust gas is lean, ratios of NOx components, which are ratios of amounts of NOx components to the total amount of NOx in said inflow exhaust gas, are calculated, and
- an increment of the stored NOx amount per unit time is calculated based on said calculated ratios of NOx components.
Dependencies are inferred from the claim text.