Toyota Jidosha Kabushiki Kaisha

Polyplastics Co., Ltd.

Kenji Furui

Arifumi Matsumoto

Makoto Ogiso

Taiga Hagimoto

Toru Kidokoro

Tomoyuki Kogo

Takeru Shirasawa

Akifumi Uozumi

Kazuya Takaoka

Hirokazu Nishijima

Kenji Hijikata

Go Hayashita

Toshio Shiwaku

Yuriko Hagimoto

Yoichi Kadota

Masato Suzuki

Koichiro Fukuda

Ryohei Ono

Ryohei Ohno

Ryosuke Kayanuma

Suzuki Masato

An exhaust gas control apparatus for the internal combustion engine includes a catalyst disposed in an exhaust passage, an upstream air-fuel ratio sensor configured to detect an air-fuel ratio of in-flow exhaust gas that flows into the catalyst, a downstream air-fuel ratio sensor configured to detect an air-fuel ratio of out-flow exhaust gas that flows out of the catalyst, and an electronic control unit configured to control the air-fuel ratio of the in-flow exhaust gas. The electronic control unit is configured to, when a predetermined condition is satisfied, control the air-fuel ratio of the in-flow exhaust gas based on an output from the downstream air-fuel ratio sensor without using an output from the upstream air-fuel ratio sensor. The electronic control unit is configured to, when the predetermined condition is not satisfied, control the air-fuel ratio of the in-flow exhaust gas based on the output from the upstream air-fuel ratio sensor.

Exhaust gas control apparatus for internal combustion engine and exhaust gas control method for the same

A catalyst degradation detection apparatus includes an air-fuel ratio detector disposed downstream of a catalyst and configured to detect an air-fuel ratio of exhaust gas flowing out from the catalyst, and an electronic control unit configured to control an air-fuel ratio of inflow exhaust gas flowing into the catalyst and determine whether the catalyst is degraded. The electronic control unit is configured to execute degradation determination control that brings the air-fuel ratio of the inflow exhaust gas to an air-fuel ratio leaner or richer than a stoichiometric air-fuel ratio. The electronic control unit is configured to determine whether precious metal of the catalyst is degraded based on the air-fuel ratio detected by the air-fuel ratio detector when an oxygen storage amount of the catalyst is varying in the degradation determination control.

Catalyst degradation detection apparatus

The catalyst deterioration detection systemcomprises an air-fuel ratio detection devicedetecting an air-fuel ratio of an exhaust gas flowing out from the catalyst, an air-fuel ratio control part, and a deterioration judgment part. The air-fuel ratio control part is configured to perform a lean control making the air-fuel ratio of the inflowing exhaust gas leaner than a stoichiometric air-fuel ratio and a rich control making the air-fuel ratio of the inflowing exhaust gas richer than the stoichiometric air-fuel ratio. The deterioration judgment part is configured to calculate an amplitude of an air-fuel ratio of an exhaust gas flowing out from the catalyst due to the lean control and the rich control based on an output of the air-fuel ratio detection device and judge that the catalyst is deteriorating if the amplitude is equal to or greater than a threshold value.

Catalyst deterioration detection system

An exhaust purification system of an internal combustion engine includes a catalyst arranged in an exhaust passage of the internal combustion engine and able to store oxygen, a storage amount calculating part configured to calculate an oxygen storage amount of the catalyst, a poisoning amount calculating part configured to calculate a poisoning amount of the catalyst, and an oxygen amount control part configured to control an amount of oxygen supplied to the catalyst based on the oxygen storage amount and the poisoning amount.

Exhaust purification system of internal combustion engine

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

An amount of reducing agent adsorbed on a NOx catalyst when a reducing agent supply device is normal and a corresponding detected value may be estimated. The corresponding detected value may be detected by a NOx sensor, and the detected value may correspond to an amount of reducing agent adsorbed on the NOx catalyst. When the estimated amount of adsorption is larger than or equal to a first amount and is smaller than or equal to a second amount, a diagnosis of the NOx catalyst based on the detected value of the NOx sensor may be prevented. The first amount may be an amount of adsorbed reducing agent corresponding to a minimum value of the corresponding detected value. The second amount may be an amount of adsorbed reducing agent corresponding to the corresponding detected value when the amount of adsorbed reducing agent is zero and larger than the first amount.

Malfunction diagnosis apparatus and malfunction diagnosis method

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.

Exhaust gas purification apparatus of internal combustion engine

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. This allows for accurate abnormality determination with regard to the SCRF in the exhaust control system for the internal combustion engine having the SCRF.

Exhaust control system for internal combustion engine

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

A diagnostic system for an internal combustion engine is disclosed. The diagnostic system may include an electronic control unit. The electronic control unit may determine whether a predetermined condition is satisfied. The predetermined condition may be a condition under which an amount of particulate matter that separates from a filter is larger than or equal to a predetermined separation amount as a urea water-originated deposit once accumulated in the filter separates in gaseous form. When the electronic control unit determines that the predetermined condition is satisfied, the electronic control unit may not execute a diagnosis of a malfunction in the filter based on a filter differential pressure until a predetermined period elapses from the point in time at which it is determined that the predetermined condition is satisfied.

Diagnostic system for internal combustion engine

An object of the invention is to suppress a reduction in accuracy of abnormality diagnosis with an abnormality diagnosis device for an exhaust gas control apparatus that performs the abnormality diagnosis regarding the exhaust gas control apparatus by using the amount of NOflowing into an SCR catalyst as a parameter. In the abnormality diagnosis device for an exhaust gas control apparatus according to the invention provided with an exhaust gas control apparatus including the SCR catalyst, a supply device supplying ammonia to the exhaust gas control apparatus, an EGR device allowing some of exhaust gas to flow back to an intake passage from an exhaust passage further downstream than the supply device, acquiring means for acquiring a NOinflow amount as the amount of NOflowing into the exhaust gas control apparatus, and diagnostic means for diagnosing an abnormality of the exhaust gas control apparatus by using the NOinflow amount acquired by the acquiring means as a parameter, the abnormality diagnosis regarding the exhaust gas control apparatus by the diagnostic means is prohibited in a case where the amount of the ammonia allowed to flow back along with the exhaust gas by the EGR device exceeds an upper limit value.

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Sunto-gun, Japan

Kenji Furui