Abstract: An object is to prevent abrasion inside an addition valve and clogging of the addition valve due to an increase in the particle diameter of precipitates. A first control is performed by which a pump is caused to operate in such a way as to return urea solution contained in the addition valve and a urea solution channel to a tank by a predetermined quantity. After the lapse of a certain time after the end of the first control, a second control is performed by which the pump is caused to operate in such a way as to return the urea solution remaining in the addition valve and the urea solution channel thoroughly to the tank.

Abstract: An exhaust gas control apparatus for an internal combustion engine includes an addition valve, a tank, a urea water passage, a pump, a nitrogen oxides catalyst, and an electronic control unit. The electronic control unit is configured to: control the pump, as a first control, such that a specified amount of the urea water stored in the addition valve and the urea water passage is returned to the tank after the internal combustion engine is stopped; control the pump, as a second control, such that the specified amount or more of the urea water in the tank is discharged from the tank to the urea water passage after the first control is executed; and control the pump, as a third control, such that all the urea water stored in the addition valve and the urea water passage is returned to the tank after the second control is executed.

Abstract: An exhaust purification system including a particulate filter , a selective reduction catalyst provided at a downstream side from the filter, an ammonia ingredient feed device which feeds an ammonia ingredient to the selective reduction catalyst, a control device which controls the amount of the ammonia ingredient which is adsorbed at the selective reduction catalyst to become a target adsorption amount, and a filter regeneration system which performs filter regeneration processing to remove PM which has built up on the particulate filter when an execution start condition stands. When removal of PM is demanded, so long as the execution start condition of the filter regeneration processing by the filter regeneration system does not stand, the target adsorption amount is decreased a plurality of times in stages, and the execution start condition of the filter regeneration processing is changed to a different condition at each stage of the target adsorption amount.

Abstract: A gel which contains a component of a catalyst is prepared. The gel and another gel are arranged in layers at a position which faces open ends of exhaust flow passages of a wall flow-type particulate filter. Next, a pusher is used to push and pack the gel and other gel through the open ends to the insides of the exhaust flow passages. Next, the particulate filter is made to dry to thereby make the partition walls carry the catalyst on their surfaces or in their micropores.

Abstract: An estimated trapped amount (PM) that is an estimated value of an amount of particulate matter that is trapped in a particulate filter arranged in an engine exhaust passage is calculated based on an engine operating state, and PM removal control is performed when the estimated trapped amount exceeds an upper limit amount. Reference temperature increase control is performed to remove the particulate matter from the particulate filter, and an actual temperature that is the temperature of the particulate filter while the reference temperature increase control is being performed is detected. A reference temperature that is the temperature of the particulate filter when it is assumed that the reference temperature increase control has been performed when the amount of particulate matter trapped in the particulate filter is a reference initial trapped amount is stored in advance. The estimated trapped amount is corrected based on the actual temperature and the reference temperature.

Abstract: An exhaust gas purification apparatus of an internal combustion engine includes: a reducing agent passage that connects a tank and an injection valve; a heater that heats up a hydrolysis catalyst that is provided in the reducing agent passage; and a controller comprising at least one processor configured to control a pump so that a reducing agent located further toward a side of the injection valve than the hydrolysis catalyst flows toward a side of the hydrolysis catalyst after completion of injection of a reducing agent in a state where the hydrolysis catalyst is at a temperature lower than the hydrolysis temperature and before start of injection of a reducing agent in a state where the hydrolysis catalyst is at a temperature equal to or higher than the hydrolysis temperature.

Abstract: A NOx catalyst is provided that can realize a favorable NOx reduction in a broad temperature region and that can lighten the overhead involved in production.

Abstract: An apparatus may have a selective catalytic reduction NOx catalyst including a high-temperature catalyst layer having high capability of reducing NOx at high temperatures and a low-temperature catalyst layer having higher capability of reducing NOx at low temperatures than that of the high-temperature catalyst layer. The low-temperature catalyst layer may be arranged closer to a catalyst substrate than the high-temperature catalyst layer. A supply valve may add an addition quantity of reducing agent for reducing NOx to exhaust gas flowing into the selective catalytic reduction NOx catalyst. A controller may comprise at least one processor configured to control addition of the reducing agent by the supply valve such that the reducing agent concentration in a reducing agent atmosphere formed in the exhaust gas flowing into the selective catalytic reduction NOx catalyst is higher when the temperature of the selective catalytic reduction NOx catalyst is in a specific low temperature range.

Abstract: An object is to provide technology that enables an NOx catalyst to exercise its NOx reduction capability satisfactorily at any flow speed of the exhaust gas flowing into the NOx catalyst. An exhaust gas purification apparatus for an internal combustion engine includes a selective catalytic reduction NOx catalyst including at least a first catalyst layer having capability of reducing NOx and a second catalyst layer having oxidation capability and arranged closer to a catalyst substrate than the first catalyst layer. The apparatus has a supply valve for adding a specific addition quantity of reducing agent for reducing NOx to inflowing exhaust gas flowing into the selective catalytic reduction NOx catalyst.

Abstract: An exhaust purification device for an internal combustion engine is provided with an NOx adsorbent for adsorbing NOx in exhaust gas and an NOx purifying catalyst for purifying NOx in exhaust gas, which are arranged in an engine exhaust passage. An electric heater is provided for raising the temperature of the NOx adsorbent. When a signal requesting startup of an internal combustion engine is issued, the device starts to supply electric power to the electric heater before the internal combustion engine completely warms up, and supplies the electric heater with a quantity of electric power making the temperature of the NOx adsorbent equal to or higher than the moisture desorption temperature but lower than the NOx desorption temperature.

Abstract: Micropore zones ZMI are defined at upstream sides of partition walls 72 of a particulate filter and macropore zones ZMA are defined at downstream sides of partition walls. The pore size of the partition walls at the micropore zones is set so that the particulate matter and the ash can be trapped by the partition walls at the micropore zones, while the pore size of the partition walls at the macropore zones is set so that the ash can pass through the partition walls at the macropore zones. When a quantity of trapped particulate matter is smaller than a limit quantity, control for increasing gas which temporarily increases the flow rate of the gas which flows into the particulate filter in order to remove the ash from the particulate filter, is performed.

Abstract: An exhaust gas purification apparatus of an internal combustion engine includes: a reducing agent passage that connects a tank and an injection valve; a heater that heats up a hydrolysis catalyst that is provided in the reducing agent passage; and a controller comprising at least one processor configured to control a pump so that a reducing agent located further toward a side of the injection valve than the hydrolysis catalyst flows toward a side of the hydrolysis catalyst after completion of injection of a reducing agent in a state where the hydrolysis catalyst is at a temperature lower than the hydrolysis temperature and before start of injection of a reducing agent in a state where the hydrolysis catalyst is at a temperature equal to or higher than the hydrolysis temperature.

Abstract: An exhaust gas purification filter includes an inflow/outflow passage through which exhaust gas flows in/out, and a partition. The outflow passage and the inflow passage is alternately arranged. The partition is configured to divide the inflow passage and the outflow passage from each other, and being porous. The partition includes a coated zone where a surface of a base of the partition is covered with a first coating layer having an average pore diameter smaller than an average pore diameter of the base, and a non-coated zone where the surface of the base is not covered with the first coating layer on a downstream side of the coated zone. The average pore diameter of the base is large enough for ash to pass through the partition, and the first coating layer is constituted by a plurality of particle groups with different average particle diameters from each other.

Abstract: An engine exhaust purification device comprises: a selective reduction type NOx catalyst; an oxidation catalyst disposed on an upstream side of the NOx catalyst; a reducing agent adding device which adds an NOx reducing agent to an exhaust gas of an engine; a control device which controls the reducing agent adding device; and an NO2 ratio calculation device which estimates an NO2 ratio of the exhaust gas flowing into the NOx catalyst. The NO2 ratio of the exhaust gas flowing into the NOx catalyst is calculated by a catalytic reaction model where the oxidation reaction of NO in the oxidation catalyst is numerically formulated, and the NO2 ratio is reflected to calculate an amount of ammonia adsorbed on the NOx catalyst by a catalytic reaction model where a chemical reaction concerned with the reduction of NOx in the NOx catalyst is numerically formulated.

Abstract: An engine exhaust purification device comprises: a selective reduction type NOx catalyst; an oxidation catalyst disposed on an upstream side of the NOx catalyst; a reducing agent adding device which adds an NOx reducing agent to an exhaust gas of an engine; a control device which controls the reducing agent adding device; and an NO2 ratio calculation device which estimates an NO2 ratio of the exhaust gas flowing into the NOx catalyst. The NO2 ratio of the exhaust gas flowing into the NOx catalyst is calculated by a catalytic reaction model where the oxidation reaction of NO in the oxidation catalyst is numerically formulated, and the NO2 ratio is reflected to calculate an amount of ammonia adsorbed on the NOx catalyst by a catalytic reaction model where a chemical reaction concerned with the reduction of NOx in the NOx catalyst is numerically formulated.