Toyota Jidosha Kabushiki Kaisha

Takeru Shirasawa

Makoto Ogiso

Kenji Furui

Toru Kidokoro

Tomihisa Oda

Bungo Kawaguchi

Tomomi Onishi

Satoshi Kobayakawa

Masaaki Sato

Yuriko Hagimoto

Kazuya Takaoka

Arifumi Matsumoto

Ryohei Ono

Yoshito Nogi

Masaaki Satou

Ryohei Ohno

When an abnormality diagnosis of an SCR catalyst is carried out, diagnostic supply control is carried out in such a manner that the first estimated adsorption amount, which is an amount of adsorption of ammonia in the SCR catalyst at the time when the SCR catalyst is assumed to be in a predetermined abnormal state, becomes equal to or more than a first predetermined adsorption amount, and the second estimated adsorption amount, which is an amount of adsorption of ammonia in the SCR catalyst at the time when the SCR catalyst is assumed to be in a predetermined normal state, becomes smaller than a second predetermined adsorption amount. Then, supply decreasing control to decrease an amount of adsorption of ammonia in the SCR catalyst is carried out, after the end of the execution of the diagnostic supply control.

Abnormality diagnosis system for an exhaust gas purification apparatus

In the abnormality diagnosis device which carries out an abnormality diagnosis of the reducing agent adding device by obtaining a diagnostic parameter which is a parameter correlated with an amount of pressure drop in a reducing agent passage in the case where, from a state in which an addition valve has been closed and in which a voltage to be applied to a pump is controlled to a diagnostic voltage so that the pressure in the reducing agent passage becomes a predetermined pressure, the addition valve is made to open in a state where the voltage to be applied to the pump is maintained at the diagnostic voltage, and by making a comparison between the diagnostic parameter and a predetermined threshold value, the abnormality diagnosis is carried out by using the diagnostic parameter or the predetermined threshold value which is corrected based on the pump discharge capacity of the pump.

Abnormality diagnosis device for reducing agent adding device

Embodiments of the present disclosure may improve the accuracy of diagnosis in diagnosing whether an exhaust gas purification system having an SCR filter is faulty. It is determined that the exhaust gas purification system is faulty if the NOx removal rate with the SCR filter calculated using a measurement value of an NOx sensor is lower than or equal to a predetermined criterion removal rate. In the apparatus, a differential pressure change rate defined as the increase in a converted differential pressure value per unit increase in the filter PM deposition amount is calculated. The value of the criterion removal rate is set higher when the differential pressure change rate at the time when the measurement value of the NOx sensor is obtained is lower than a predetermined threshold than when the differential pressure change rate is higher than or equal to the predetermined threshold.

Fault diagnosis apparatus for exhaust gas purification system

Embodiments of the present disclosure may estimate the amount of ammonia adsorbed in an SCR catalyst as accurately as possible. The ammonia adsorption amount is calculated by integrating the quantity of ammonia supplied to the SCR filter, the quantity of ammonia consumed in reduction of NOx in the SCR catalyst, and the quantity of ammonia desorbed from the SCR catalyst. In the calculation, a differential pressure change rate defined as the increase in a converted differential pressure value per unit increase in the filter PM deposition amount is referred to. The ammonia desorption quantity is calculated in such a way that the calculated value of the ammonia desorption quantity is made smaller when the differential pressure change rate is smaller than a predetermined threshold than when the differential pressure change rate is equal to or higher than the predetermined threshold.

Ammonia adsorption amount estimation apparatus, ammonia adsorption amount estimation method, and exhaust gas purification system for internal combustion engine

When an integrated value of a determination value correlated with a command value for an amount of supply of a reducing agent at the time of the command value being larger than a command supply amount threshold value reaches an integration threshold value, a determination is made that a diagnosis condition is satisfied, and an abnormality in the supply of the reducing agent is diagnosed based on an integrated value of the command value for the amount of supply of the reducing agent and an integrated value of an estimated value of the amount of supply of the reducing agent, whereas in cases where a period of time in which the diagnosis condition is not satisfied is longer than a time period threshold value, an interval of supply of the reducing agent is extended.

Abnormality diagnosis device for exhaust gas purification apparatus in internal combustion engine

An object of the disclosure is to adjust the ammonia adsorption amount in an SCR catalyst supported on an SCR filter as close as possible to a target adsorption amount in an exhaust gas purification system including the SCR filter. In a system according to the disclosure, the quantity of ammonia supplied by an ammonia supplier is made smaller when a differential pressure change rate at the time when ammonia is supplied by the ammonia supplier is lower than a predetermined threshold than when the differential pressure change rate at the time when ammonia is supplied by the ammonia supplier is equal to or higher than the predetermined threshold. Moreover, when the differential pressure change rate is lower than the predetermined threshold, the change in the quantity of ammonia supplied by the ammonia supplier relative to the change in the filter PM deposition amount is kept equal to zero.

Exhaust gas purification system for an internal combustion engine

It is possible to decrease the amount of NOx emitted into the air. The amount of ammonia adsorbed on an SCR catalyst is calculated by subtracting the amount of ammonium nitrate produced on the SCR catalyst from the amount of ammonia adsorbed on the SCR catalyst at the time of starting of an internal combustion engine, and the amount of NOflowing into the SCR catalyst is decreased when an NOx purification rate estimated from the amount of ammonia adsorbed on the SCR catalyst is less than a threshold value compared to when the NOx purification rate is equal to or greater than the threshold value.

Exhaust gas control apparatus for internal combustion engine

The present invention discloses an exhaust gas purification system for an internal combustion engine, which is provided with: a low pressure EGR mechanism that is equipped with a low pressure EGR passage and a low pressure EGR valve; a selective reduction type catalyst that is arranged in a portion of the exhaust passage downstream; a supply device which serves to supply an ammonia derived compound to said selective reduction type catalyst; and a control unit that causes said supply device to supply the ammonia derived compound when said low pressure EGR valve is in a valve open state, makes the amount of the ammonia derived compound supplied from said supply device larger in cases where an amount of the low pressure EGR gas flowing through said low pressure EGR passage is large, in comparison with the case where it is small.

A decrease in determination accuracy on filter trouble due to a decrease in detection accuracy of a PM sensor is restricted. A filter, a selective reduction type NOx catalyst provided on a downstream of the filter, the PM sensor detecting an amount of PM on a downstream of the selective reduction type NOx catalyst, and a removal section conducting a process for removing a reducing agent attached to the PM sensor in a case where at least one of conditions is satisfied that a temperature of the selective reduction type NOx catalyst is equal to or lower than a threshold, that a temperature of the exhaust is equal to or lower than a threshold, that a flow rate of the exhaust is equal to or higher than a threshold, and that an adsorption amount of the reducing agent in the selective reduction type NOx catalyst is equal to or larger than a threshold are included.

Exhaust purification device for internal combustion engine

An exhaust gas purification system for an internal combustion engine, which is provided with: a selective reduction type catalyst arranged in an exhaust passage of the internal combustion engine; a low pressure EGR mechanism that is equipped with a low pressure EGR passage for introducing a part of an exhaust gas flowing through a portion of the exhaust passage downstream of a turbine of a centrifugal supercharger to a portion of an intake passage upstream of a compressor as a low pressure EGR gas, and a low pressure EGR valve for changing a channel cross section of the low pressure EGR passage; a supply device.

An exhaust gas recirculation device of an engine () of the invention comprises a first exhaust gas recirculation passage () for connecting an exhaust passage () and an intake passage () to each other and introducing into the intake passage an exhaust gas discharged from a combustion chamber () to the exhaust passage, and a second exhaust gas recirculation passage () for connecting the exhaust passage upstream of a part of the exhaust passage connected to the first exhaust gas recirculation passage and the intake passage downstream of a part of the intake passage connected to the first exhaust gas recirculation passage to each other and introducing into the intake passage the exhaust gas discharged from the combustion chamber to the exhaust passage. The amount of the exhaust gas introduced into the intake passage via the first exhaust gas recirculation passage is controlled to a first target exhaust gas recirculation amount and the amount of the exhaust gas introduced into the intake passage via the second exhaust gas recirculation passage is controlled to a second target exhaust gas recirculation amount. The amount of exhaust gas introduced into the first and second exhaust gas passages is controlled in accordance with an allowable upper flame temperature.

Growing community of inventors

Susono, Japan

Takeru Shirasawa