Abstract: 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.

Abstract: The catalyst deterioration detection system 1 comprises an air-fuel ratio detection device 41 detecting an air-fuel ratio of an exhaust gas flowing out from the catalyst 20, an air-fuel ratio control part 71, and a deterioration judgment part 72. 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.

Abstract: The catalyst deterioration detection system 1 comprises an air-fuel ratio detection device 41 detecting an air-fuel ratio of an exhaust gas flowing out from the catalyst 20, an air-fuel ratio control part 71, and a deterioration judgment part 72. 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.

Abstract: The catalyst deterioration detection system 1 comprises an air-fuel ratio detection device 41 detecting an air-fuel ratio of an exhaust gas flowing out from the catalyst 20, an air-fuel ratio control part 71, and a deterioration judgment part 72. 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.

Abstract: 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.

Abstract: The abnormality diagnosis system 1, 1?, 1? of an ammonia detection device 46, 71 comprises: an air-fuel ratio detection device 41, 72 arranged in the exhaust passage 22 at the downstream side of the catalyst 20; an air-fuel ratio control part 51 configured to control an air-fuel ratio of exhaust gas; and an abnormality judgment part 52 configured to judge abnormality of the ammonia detection device. The air-fuel ratio control part performs rich control making the air-fuel ratio of the inflowing exhaust gas richer than a stoichiometric air-fuel ratio. The abnormality judgment part judges that the ammonia detection device is abnormal if, after start of the rich control, an output value of the ammonia detection device does not rise to a reference value before the air-fuel ratio detected by the air-fuel ratio detection device falls to a rich judged air-fuel ratio richer than a stoichiometric air-fuel ratio.

Abstract: An object is to reduce the influence of a hydrogen-ascribable difference between the measurement value of an oxygen sensor and the actual value. An exhaust system includes an oxygen sensor configured to measure the air-fuel ratio of exhaust gas provided in an exhaust passage of an internal combustion engine and including a diffusion rate limiting layer and a controller configured to correct the measurement value of the oxygen sensor in such a way as to increase the measurement value of the oxygen sensor by an amount of correction that is made larger when the responsivity of the oxygen sensor to changes in the air-fuel ratio of the internal combustion engine is high than when it is low in the same operation state of the internal combustion engine.

Abstract: A control device of an exhaust sensor comprises a heater control part configured to set a target temperature of an electrochemical cell and control a heater so that a temperature of the electrochemical cell becomes the target temperature, and a judging part configured to judge whether a water repellency of a protective layer is falling when the heater control part sets the target temperature to a temperature of a lowest temperature at which a Leidenfrost phenomenon occurs at an outer surface of the protective layer or more. The heater control part is configured to rise the target temperature when the judging part judges that the water repellency of the protective layer is falling.

Abstract: A control system of an exhaust sensor controlling an exhaust sensor comprises a heater control part controlling a heater and a temperature estimating part estimating a temperature of an exhaust pipe around the exhaust sensor. The heater control part sets the target temperature to a first target temperature after startup of the internal combustion engine and until the estimated temperature of the exhaust pipe reaches a first exhaust pipe temperature, sets the target temperature to a second target temperature from when the estimated temperature of the exhaust pipe reaches the first exhaust pipe temperature to when it reaches a second exhaust pipe temperature, and sets the target temperature to an operating temperature of the electrochemical cell when the estimated temperature of the exhaust pipe reaches the second exhaust pipe temperature.

Abstract: A control device for an internal combustion engine performs feedback control so that the air-fuel ratio of the exhaust gas flowing into an exhaust purification catalyst becomes a target air-fuel ratio and switches the target air-fuel ratio to lean when an output air-fuel ratio of a downstream side air-fuel ratio sensor is judged rich and switches the target air-fuel ratio to rich when an output air-fuel ratio of the downstream side air-fuel ratio sensor is judged lean. The control device judges that the downstream side air-fuel ratio sensor has not become abnormal when the value of the excess/deficiency parameter from when switching the target air-fuel ratio to lean or rich to when the output air-fuel ratio of the downstream side air-fuel ratio sensor is judged rich or lean is larger than a predetermined limit value.

Abstract: An object of the present invention is to provide an exhaust system component having excellent properties to be located in an exhaust flow path from an internal combustion engine, particularly, an exhaust system component having an extended use-life. The exhaust system component of the present invention for an internal combustion engine has a self-healing ceramic material and an electric heater for heating the self-healing ceramic material. In particular, the exhaust system component of the present invention is an oxygen sensor having a detection element and an electric heater, wherein the detection element has a solid electrolyte layer, a reference-side electrode layer, an exhaust-side electrode layer, and a diffusion layer and/or a trap layer each composed of a self-healing ceramic material.

Abstract: An exhaust purification system comprises an exhaust purification catalyst 20, an NOX sensor 46, air-fuel ratio sensor 41 downstream of the catalyst 20, and a control and diagnosis device. The device alternately sets a target air-fuel ratio to a rich air-fuel ratio and a lean air-fuel ratio and switches the target air-fuel ratio from the rich air-fuel ratio to the lean air-fuel ratio when the output air-fuel ratio of the air-fuel ratio sensor becomes a rich judged air-fuel ratio or less. The device diagnoses abnormality of the catalyst based on the output of the NOX sensor. It diagnoses abnormality of the catalyst when the air-fuel ratio of the exhaust gas flowing into the catalyst is a rich air-fuel ratio, but does not diagnose abnormality of the catalyst when the air-fuel ratio of the exhaust gas flowing into the catalyst is a lean air-fuel ratio.

Abstract: The exhaust purification system of an internal combustion engine comprises: a catalyst arranged in an exhaust passage of the internal combustion engine and able to store oxygen; an ammonia detection device arranged in the exhaust passage at a downstream side of the catalyst in a direction of flow of exhaust; and an air-fuel ratio control part configured to control an air-fuel ratio of inflowing exhaust gas flowing into the catalyst to a target air-fuel ratio. The air-fuel ratio control part is configured to perform rich control making the target air-fuel ratio richer than a stoichiometric air-fuel ratio, and make the target air-fuel ratio leaner than the stoichiometric air-fuel ratio when an output value of the ammonia detection device rises to a reference value in the rich control.

Abstract: This control device for an internal combustion engine is equipped with: an air/fuel ratio sensor; and an engine control device that controls the internal combustion engine according to the output of the air/fuel ratio sensor. The air/fuel ratio sensor is configured so that the applied voltage at which the output current reaches zero varies according to the exhaust air/fuel ratio, and the output current increases if the applied voltage is increased at the air/fuel ratio sensor when the exhaust air/fuel ratio is the stoichiometric air/fuel ratio.

Abstract: A control device of an internal combustion engine comprises a heater control part configured to set a target temperature of the electrochemical cell and control the heater so that a temperature of the electrochemical cell becomes the target temperature. The heater control part sets the target temperature to a first temperature when water injection by the water injection device is not being demanded after a predetermined time elapses from startup of the internal combustion engine, and sets the target temperature to a second temperature when an operating state of the internal combustion engine is in a water outflow state where water injected by the water injection device reaches the exhaust passage without going through combustion of air-fuel mixture in the combustion chamber. The second temperature is higher than the first temperature.

Abstract: A sensor for detecting oxygen concentration in exhaust gas or an air-fuel ratio provided with a solid electrolyte body, an exhaust gas side electrode being disposed on one side of the solid electrolyte body and being in contact with the exhaust gas, an atmosphere side electrode being disposed on the other side of the solid electrolyte body and being in contact with the atmosphere, and an electric circuit applying a reference voltage between these electrodes is arranged in an engine exhaust passage. The sensor for detecting the oxygen concentration in the exhaust gas or the air-fuel ratio has a characteristic in which an output current continues to increase without having a limiting current region when the voltage applied between the electrodes is increased while the air-fuel ratio is constant. The air-fuel ratio is controlled based on the output current of the sensor for detecting the oxygen concentration in the exhaust gas or the air-fuel ratio.

Abstract: An internal combustion engine includes an ECU, an A/F sensor being active at a first temperature lower than a PM combustion temperature and set in advance, and a heater to heat the A/F sensor to a second temperature equal to or higher than the PM combustion temperature and set in advance. The ECU detects PM based on a difference between an output value of the A/F sensor at the first temperature and an output value of the A/F sensor at the second temperature. The ECU may perform determining that a PM accumulation amount is smaller than a reference amount when the output value is higher than a threshold value, and that the PM accumulation amount is equal to or larger than the reference amount when the output value is a value equal to or smaller than the threshold value.

Abstract: The control system of an internal combustion engine controls an internal combustion engine comprising an exhaust sensor. The control system comprises a motoring device driving rotation of a crankshaft of the internal combustion engine, a motoring control part configured to control the motoring device, a heater control part configured to control supply of electric power to the heater, and a temperature estimating part configured to estimate a temperature of the sensor element. The motoring control part is configured to drive the motoring device for a predetermined time when the temperature of the sensor element estimated by the temperature estimating part is outside a predetermined cracked element temperature region while the heater control part is supplying electric power to the heater, and stop driving the motoring device when the temperature of the sensor element is within the cracked element temperature region.

Abstract: A control device of an exhaust sensor comprises a cell temperature detecting part detecting a temperature of the electrochemical cell, a heater control part controlling the heater so that a temperature of the electrochemical cell becomes the target temperature, and a judging part judging whether a water repellency of the protective layer is falling. The judging part judges that the water repellency of the protective layer is falling if a condition for judging abnormality is satisfied. The condition for judging abnormality includes a temperature of the electrochemical cell detected by the cell temperature detecting part falling from the target temperature and a speed of fall of the temperature being faster than a speed of fall of the temperature of the electrochemical cell when the heater is turned off.

Abstract: An exhaust purification system comprises an exhaust purification catalyst 20, an NOX sensor 46, air-fuel ratio sensor 41 downstream of the catalyst 20, and a control and diagnosis device. The device alternately sets a target air-fuel ratio to a rich air-fuel ratio and a lean air-fuel ratio and switches the target air-fuel ratio from the rich air-fuel ratio to the lean air-fuel ratio when the output air-fuel ratio of the air-fuel ratio sensor becomes a rich judged air-fuel ratio or less. The device diagnoses abnormality of the catalyst based on the output of the NOX sensor. It diagnoses abnormality of the catalyst when the air-fuel ratio of the exhaust gas flowing into the catalyst is a rich air-fuel ratio, but does not diagnose abnormality of the catalyst when the air-fuel ratio of the exhaust gas flowing into the catalyst is a lean air-fuel ratio.