Abstract: An exhaust gas purification device for an internal combustion engine purifies exhaust gas in a first exhaust path and a second exhaust path. The device includes a confluent path. The confluent path extends from a confluent section of the first exhaust path and the second exhaust path. A first auxiliary NOx catalyst is provided in the first exhaust path. A second auxiliary NOx catalyst is provided in the second exhaust path. A main NOx catalyst is provided in the confluent path. A first addition section adds an ammonia source in a first addition amount to a section upstream of the first auxiliary NOx catalyst to supply urea water to the first auxiliary NOx catalyst. A second addition section adds an ammonia source in a second addition amount to a section upstream of the second auxiliary NOx catalyst to supply urea water to the second auxiliary NOx catalyst.

Abstract: To estimate an amount of reducing agent adsorbed to a selective reduction type NOx catalyst with a higher degree of precision while maintaining a condition in which NOx can be purified by the selective reduction type NOx catalyst, the present invention includes: an upper limit value calculation unit that calculates an upper limit value of a reducing agent amount that is adsorbed to the selective reduction type NOx catalyst when the reducing agent is supplied continuously during a steady state operation in an internal combust ion engine; and an estimation unit that estimates an upper limit value calculated by the upper limit value calculation unit when the reducing agent is supplied for at least a predetermined time during the steady state operation in the internal combustion engine to be the reducing agent amount adsorbed to the selective reduction type NOx catalyst at that time.

Abstract: The NOx storage catalyst and the NOx selective reduction catalyst are arranged in the engine exhaust passage. In the engine low load operating region, a combustion is performed in the combustion chamber under a lean base air-fuel ratio and the air-fuel ratio in the combustion chamber is made rich when NOx should be released from the NOx storage catalyst. In the engine medium load operating region, the base air-fuel ratio is made smaller, a degree of richness of the air-fuel ratio is made smaller, and a period in which the air-fuel ratio is made rich is made shorter so that an amount of ammonia which is produced per unit time when the air-fuel ratio is made rich falls compared with the time of engine low load operation.

Abstract: A wall flow type particulate filter is arranged inside the exhaust passage of an internal combustion engine where combustion is performed under an excess of oxygen. The particulate filter carries a solid acid. The solid acid has an acid strength which is higher than the acid strength of sulfurous acid and lower than the acid strength of sulfuric acid. To remove the ash from the particulate filter, ash atomization processing for rendering the state of the particulate filter a state where the exhaust gas which flows into the particulate filter is lowered in concentration of oxygen and the particulate filter is raised in temperature is temporarily performed.

Abstract: An object of the present invention is to provide a technique with which an amount of reducing agent adsorbed to a selective reduction type NOx catalyst provided in an exhaust passage of an internal combustion engine can be controlled to a target adsorption amount. In an exhaust gas purification system for an internal combustion engine according to the present invention, when a reducing agent adsorption amount adsorbed on a selective reduction type NOx catalyst is held at a target adsorption amount, a reducing agent supply amount supplied from a supply apparatus per unit time is controlled to an amount obtained by adding a predetermined amount to a reduction consumption amount, which is an amount of reducing agent consumed per unit time by the selective reduction type NOx catalyst for NOx reduction.

Abstract: To estimate an amount of reducing agent adsorbed to a selective reduction type NOx catalyst with a higher degree of precision, an amount of variation over a predetermined time in a reducing agent amount adsorbed to a selective reduction type NOx catalyst is calculated from an upper limit value of a reducing agent amount that is adsorbed to the selective reduction type NOx catalyst when the reducing agent is supplied continuously by a supply unit, which is calculated on the basis of a temperature of the selective reduction type NOx catalyst, and the reducing agent amount adsorbed to the selective reduction type NOx catalyst, whereupon a reducing agent amount adsorbed to the selective reduction type NOx catalyst following the elapse of the predetermined time is estimated by adding the variation amount to the reducing agent amount adsorbed to the selective reduction type NOx catalyst.

Abstract: A particulate filter arranged in an engine exhaust passage is provided with alternately arranged exhaust gas inflow and outflow passages and porous partition walls which separate these passages from each other. In each partition wall, a coated zone where a coated layer with an average pore size smaller than that of a partition wall substrate is used to cover the substrate surface and a non-coated zone downstream of the coated zone where the substrate surface is not covered by said coated layer, are defined, and the ash in the exhaust gas can pass through the partition wall in the non-coated zone. Judgment processing which judges if a particulate matter trapping rate of the particulate filter has fallen below an allowable lower limit value is performed. PM removal processing is performed when it is judged that the particulate matter trapping rate has fallen below the allowable lower limit value.

Abstract: A wall flow type particulate filter is arranged inside the exhaust passage of an internal combustion engine where combustion is performed under an excess of oxygen. The particulate filter carries a solid acid. The solid acid has a Hammett acidity function smaller than ?0.83 and larger than ?12 in the standard state. To remove the ash from the particulate filter, ash atomization processing for rendering the state of the particulate filter a state where the exhaust gas which flows into the particulate filter is lowered in concentration of oxygen and the particulate filter is raised in temperature is temporarily performed.

Abstract: A wall flow type particulate filter is arranged inside the exhaust passage of an internal combustion engine where combustion is performed under an excess of oxygen. The particulate filter carries an ash atomization agent. To remove the ash from the particulate filter, ash atomization processing for rendering the state of the particulate filter a state where the exhaust gas which flows into the particulate filter is lowered in concentration of oxygen and the particulate filter is raised in temperature is temporarily performed.

Abstract: A wall flow type particulate filter (24) adapted to be arranged in an exhaust passage of an internal combustion engine in which combustion is performed in an excess of oxygen carries a solid acid. The solid acid has an acid strength which is higher than the acid strength of sulfurous acid and lower than the acid strength of sulfuric acid.

Abstract: An exhaust gas purification device for an internal combustion engine purifies exhaust gas in a first exhaust path and a second exhaust path. The device includes a confluent path. The confluent path extends from a confluent section of the first exhaust path and the second exhaust path. A first auxiliary NOx catalyst is provided in the first exhaust path. A second auxiliary NOx catalyst is provided in the second exhaust path. A main NOx catalyst is provided in the confluent path. A first addition section adds an ammonia source in a first addition amount to a section upstream of the first auxiliary NOx catalyst to supply urea water to the first auxiliary NOx catalyst. A second addition section adds an ammonia source in a second addition amount to a section upstream of the second auxiliary NOx catalyst to supply urea water to the second auxiliary NOx catalyst.

Abstract: An object of the invention is to suppress deposition of ash in a wall-flow particulate filter while curtailing drops in a trapping rate of PM. To attain the above object, the invention provides a wall-flow particulate filter delimited by porous partition walls having pores of a size that allows ash and ash aggregates to pass therethrough. In the filter, a coat layer having pores smaller than the pores of the partition walls is provided, at a region of the partition walls, from an upstream end thereof up to a position before a downstream end thereof.

Abstract: An exhaust purification system of an internal combustion engine, which includes: a silver-alumina-based catalyst, which is arranged in an engine exhaust system and, when an air-fuel ratio of exhaust gas is leaner than a stoichiometric air-fuel ratio, releases adsorbed NO2 at a first set temperature and adsorbed NO at a second set temperature, a secondary air feed passage configured to suppress a temperature rise of the silver-alumina-based catalyst; and an electronic control unit, that: controls the air flow through the secondary air feed passage to: when the silver-alumina-based catalyst has reached a third set temperature, suppress a temperature rise of the silver-alumina-based catalyst to maintain the silver-alumina-based catalyst near the third set temperature, and then lift the suppression of the temperature rise of the silver-alumina-based catalyst so that at least part of the NO adsorbed at the silver-alumina-based catalyst, is oxidized to NO2 to be adsorbed at the silver-alumina-based catalyst.

Abstract: 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.

Abstract: A wall flow type particulate filter is arranged inside the exhaust passage of an internal combustion engine where combustion is performed under an excess of oxygen. The particulate filter carries a solid acid. The solid acid has an acid strength which is higher than the acid strength of sulfurous acid and lower than the acid strength of sulfuric acid. To remove the ash from the particulate filter, ash atomization processing for rendering the state of the particulate filter a state where the exhaust gas which flows into the particulate filter is lowered in concentration of oxygen and the particulate filter is raised in temperature is temporarily performed.

Abstract: A method of removing ash from a wall flow type particulate filter which is arranged in an exhaust passage of an internal combustion engine in which combustion is performed in an excess of oxygen for trapping particulate matter in exhaust gas, using a solid acid which is carried on the particulate filter, renders the state of the particulate filter a state where the exhaust gas which flows into the particulate filter is lowered in concentration of oxygen and the particulate filter is raised in temperature, and then renders the state of the particulate filter a state where the exhaust gas which flows into the particulate filter in an oxidizing atmosphere contains SOx.

Abstract: A wall flow type particulate filter is arranged inside the exhaust passage of an internal combustion engine where combustion is performed under an excess of oxygen. The particulate filter carries an ash atomization agent. To remove the ash from the particulate filter, ash atomization processing for rendering the state of the particulate filter a state where the exhaust gas which flows into the particulate filter is lowered in concentration of oxygen and the particulate filter is raised in temperature is temporarily performed.

Abstract: A wall flow type particulate filter is arranged inside the exhaust passage of an internal combustion engine where combustion is performed under an excess of oxygen. The particulate filter carries a solid acid. The solid acid has a Hammett acidity function smaller than ?0.83 and larger than ?12 in the standard state. To remove the ash from the particulate filter, ash atomization processing for rendering the state of the particulate filter a state where the exhaust gas which flows into the particulate filter is lowered in concentration of oxygen and the particulate filter is raised in temperature is temporarily performed.

Abstract: A wall flow type particulate filter (24) adapted to be arranged in an exhaust passage of an internal combustion engine in which combustion is performed in an excess of oxygen carries a solid acid. The solid acid has an acid strength which is higher than the acid strength of sulfurous acid and lower than the acid strength of sulfuric acid.

Abstract: A method of removing ash from a wall flow type particulate filter which is arranged in an exhaust passage of an internal combustion engine in which combustion is performed in an excess of oxygen for trapping particulate matter in exhaust gas, using a solid acid which is carried on the particulate filter, renders the state of the particulate filter a state where the exhaust gas which flows into the particulate filter is lowered in concentration of oxygen and the particulate filter is raised in temperature, and then renders the state of the particulate filter a state where the exhaust gas which flows into the particulate filter in an oxidizing atmosphere contains SOx.