Abstract: The invention provides a technique for more accurately executing failure diagnosis for an exhaust gas control apparatus having both a selective reduction function and a filter function. To this end, a failure diagnosis apparatus according to the invention for the exhaust gas control apparatus having both the selective reduction function and the filter function computes a NOx purification rate pertaining to a case where the exhaust gas control apparatus is normal based on an estimated value of the amount of particulate matter (PM) collected or accumulated in the exhaust gas control apparatus and an estimated value of the NO2 ratio of exhaust gas flowing into the exhaust gas control apparatus, and determines that the exhaust gas control apparatus fails when the difference between the result of the calculation and an actual NOx purification rate exceeds a threshold.

Abstract: An additive amount of a reducing agent to a selective reduction-type NOx catalyst is optimized. An ammonia adsorption amount of the selective reduction-type NOx catalyst is estimated based on one or a plurality of prescribed parameters related to the ammonia adsorption amount and a specific ammonia adsorption amount that is an estimated value of the ammonia adsorption amount specified by at least one of a maximum value and a minimum value of an estimated value of the ammonia adsorption amount is estimated based on an error in the prescribed parameter, and when the specific ammonia adsorption amount is outside a target range of the ammonia adsorption amount, addition of an ammonia precursor or ammonia using an adding valve is controlled such that the specific ammonia adsorption amount returns to the target range.

Abstract: An exhaust control system for an internal combustion engine comprises: a trapping capability acquisition part that obtains information regarding a PM trapping capability, based on a detection value of an exhaust sensor provided to detect a predetermined parameter relating to an exhaust gas flowing out of an SCRF; and a NOx reduction capability acquisition part obtains information regarding a NOx reduction capability, based on an amount of NOx in the exhaust gas flowing out of the SCRF. The exhaust control system determines and distinguishes between a trapping abnormal state in which a PM trapping function by the SCRF is failed and a sensor abnormal state in which a detection function of the predetermined parameter by the exhaust sensor is failed, based on the NOx reduction capability obtained by the NOx reduction capability acquisition part, when the trapping capability obtained by the trapping capability acquisition part is in a predetermined low trapping capability state.

Abstract: An additive amount of a reducing agent to a selective reduction-type NOx catalyst is optimized. An ammonia adsorption amount of the selective reduction-type NOx catalyst is estimated based on one or a plurality of prescribed parameters related to the ammonia adsorption amount and a specific ammonia adsorption amount that is an estimated value of the ammonia adsorption amount specified by at least one of a maximum value and a minimum value of an estimated value of the ammonia adsorption amount is estimated based on an error in the prescribed parameter, and when the specific ammonia adsorption amount is outside a target range of the ammonia adsorption amount, addition of an ammonia precursor or ammonia using an adding valve is controlled such that the specific ammonia adsorption amount returns to the target range.

Abstract: An incorrect or wrong diagnosis in abnormality diagnosis of a sensor is suppressed. Provided at the downstream side of an NOx selective reduction catalyst is a sensor which detects NOx and ammonia in an exhaust gas flowing out of the NOx selective reduction catalyst, and in which the NOx and the ammonia react with each other. An amount of decrease in an output of the sensor due to a reaction of the NOx and the ammonia in the sensor is calculated based on the NOx and the ammonia flowing out of the NOx catalyst, and an abnormality diagnosis of the sensor is carried out based on this amount of decrease in the output of the sensor.

Abstract: A diagnostic apparatus for an exhaust gas purification apparatus including a selective catalytic reduction NOx catalyst (SCR catalyst) provided in an exhaust passage of an internal combustion engine, a supplying unit supplying ammonia or an ammonia precursor into exhaust gas flowing into the SCR catalyst and a sensor, provided on a downstream side of the SCR catalyst, detecting NOx and ammonia in exhaust gas. The diagnostic apparatus calculates an amount of decline in output of the sensor due to a reaction between NOx and ammonia at the sensor and performs a diagnosis of the supplying unit based on the calculated amount of decline in output of the sensor.

Abstract: An exhaust control system for an internal combustion engine comprises: a trapping capability acquisition part that obtains information regarding a PM trapping capability, based on a detection value of an exhaust sensor provided to detect a predetermined parameter relating to an exhaust gas flowing out of an SCRF; and a NOx reduction capability acquisition part obtains information regarding a NOx reduction capability, based on an amount of NOx in the exhaust gas flowing out of the SCRF. The exhaust control system determines and distinguishes between a trapping abnormal state in which a PM trapping function by the SCRF is failed and a sensor abnormal state in which a detection function of the predetermined parameter by the exhaust sensor is failed, based on the NOx reduction capability obtained by the NOx reduction capability acquisition part, when the trapping capability obtained by the trapping capability acquisition part is in a predetermined low trapping capability state.

Abstract: An abnormality diagnosis apparatus for an exhaust gas purification apparatus including a selective catalytic reduction NOx catalyst (SCR catalyst) and a sensor which detects NOx and ammonia in exhaust gas flowing out from the NOx catalyst and at which NOx and ammonia react with each other. The abnormality diagnosis apparatus calculates, based on concentrations of NOx and ammonia which flow out from the SCR catalyst, an amount of decline in output of the sensor due to a reaction between NOx and ammonia at the sensor, and performs an abnormality diagnosis of the SCR catalyst based on the calculated amount of decline in output of the sensor.

Abstract: An incorrect or wrong diagnosis in abnormality diagnosis of a sensor is suppressed. Provided at the downstream side of an NOx selective reduction catalyst is a sensor which detects NOx and ammonia in an exhaust gas flowing out of the NOx selective reduction catalyst, and in which the NOx and the ammonia react with each other. An amount of decrease in an output of the sensor due to a reaction of the NOx and the ammonia in the sensor is calculated based on the NOx and the ammonia flowing out of the NOx catalyst, and an abnormality diagnosis of the sensor is carried out based on this amount of decrease in the output of the sensor.

Abstract: A diagnostic apparatus for an exhaust gas purification apparatus including a selective catalytic reduction NOx catalyst (SCR catalyst) provided in an exhaust passage of an internal combustion engine, a supplying unit supplying ammonia or an ammonia precursor into exhaust gas flowing into the SCR catalyst and a sensor, provided on a downstream side of the SCR catalyst, detecting NOx and ammonia in exhaust gas. The diagnostic apparatus calculates an amount of decline in output of the sensor due to a reaction between NOx and ammonia at the sensor and performs a diagnosis of the supplying unit based on the calculated amount of decline in output of the sensor.

Abstract: An abnormality diagnosis apparatus for an exhaust gas purification apparatus including a selective catalytic reduction NOx catalyst (SCR catalyst) and a sensor which detects NOx and ammonia in exhaust gas flowing out from the NOx catalyst and at which NOx and ammonia react with each other. The abnormality diagnosis apparatus calculates, based on concentrations of NOx and ammonia which flow out from the SCR catalyst, an amount of decline in output of the sensor due to a reaction between NOx and ammonia at the sensor, and performs an abnormality diagnosis of the SCR catalyst based on the calculated amount of decline in output of the sensor.

Abstract: An object of the present invention is to increase the accuracy of a deterioration determination in a deterioration determination system of an exhaust emission control device having a selective reduction type NOx catalyst, by suppressing false determinations when the deterioration determination is made. The deterioration determination system includes a catalyst having an oxidative capacity downstream of a NOx catalyst using ammonia as a reducing agent. When an amount of ammonia adsorbed by the NOx catalyst is larger than an equilibrium adsorption amount, out of the amount of ammonia flowing into the catalyst having the oxidative capacity, at least one of the amount of ammonia flowing out from the catalyst having the oxidative capacity and the amount of ammonia converted to NOx in the catalyst having the oxidative capacity or a total value of both is calculated.

Abstract: When individually controlling a plurality of supply valves is not available, an object of the invention is to determine which of the plurality of supply valves is abnormal with high accuracy, while suppressing a cost increase. A first supply valve, a first selective reduction NOx catalyst, a second supply valve, a second selective reduction NOx catalyst and a NOx sensor are sequentially provided in an exhaust conduit. With a view to identifying which of abnormality of the first supply valve and abnormality of the second supply valve, an instruction is given to the first supply valve and the second supply valve to increase a supply amount of a reducing agent. This identification is based on a NOx concentration detected by the NOx sensor after elapse of a first specified time duration since an instruction time point that is a time point when this instruction is given.

Abstract: In a failure determination system that performs failure determination of an exhaust gas purification apparatus having a NOx selective catalytic reduction catalyst (NOx catalyst) that is disposed in an exhaust passage of an internal combustion engine and uses ammonia as a reducing agent, the failure determination of the exhaust gas purification apparatus is performed by a failure determination unit, based on a detected value of a NOx sensor that detects NOx in exhaust gas. Then, based on an adsorption amount difference at assumed failure that is the difference between an ammonia equilibrium adsorption amount in the NOx catalyst in an equilibrium state of ammonia adsorption, assuming that the exhaust gas purification apparatus is in a predefined failure state, and an actual ammonia adsorption amount in the NOx catalyst, the failure determination itself by the failure determination unit is inhibited or the use of the NOx sensor in the failure determination is restricted.

Abstract: An object of the present invention is to increase the accuracy of a deterioration determination in a deterioration determination system of an exhaust emission control device having a selective reduction type NOx catalyst, by suppressing false determinations when the deterioration determination is made. The deterioration determination system includes a catalyst having an oxidative capacity downstream of a NOx catalyst using ammonia as a reducing agent. When an amount of ammonia adsorbed by the NOx catalyst is larger than an equilibrium adsorption amount, out of the amount of ammonia flowing into the catalyst having the oxidative capacity, at least one of the amount of ammonia flowing out from the catalyst having the oxidative capacity and the amount of ammonia converted to NOx in the catalyst having the oxidative capacity or a total value of both is calculated.

Abstract: The invention provides a technique for more accurately executing failure diagnosis for an exhaust gas control apparatus having both a selective reduction function and a filter function. To this end, a failure diagnosis apparatus according to the invention for the exhaust gas control apparatus having both the selective reduction function and the filter function computes a NOx purification rate pertaining to a case where the exhaust gas control apparatus is normal based on an estimated value of the amount of particulate matter (PM) collected or accumulated in the exhaust gas control apparatus and an estimated value of the NO2 ratio of exhaust gas flowing into the exhaust gas control apparatus, and determines that the exhaust gas control apparatus fails when the difference between the result of the calculation and an actual NOx purification rate exceeds a threshold.

Abstract: In a failure determination system that performs failure determination of an exhaust gas purification apparatus having a NOx selective catalytic reduction catalyst (NOx catalyst) that is disposed in an exhaust passage of an internal combustion engine and uses ammonia as a reducing agent, the failure determination of the exhaust gas purification apparatus is performed by a failure determination unit, based on a detected value of a NOx sensor that detects NOx in exhaust gas. Then, based on an adsorption amount difference at assumed failure that is the difference between an ammonia equilibrium adsorption amount in the NOx catalyst in an equilibrium state of ammonia adsorption, assuming that the exhaust gas purification apparatus is in a predefined failure state, and an actual ammonia adsorption amount in the NOx catalyst, the failure determination itself by the failure determination unit is inhibited or the use of the NOx sensor in the failure determination is restricted.