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: This control device for an internal combustion engine is equipped with: an air/fuel ratio sensor provided to the exhaust passage of an internal combustion engine; 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 equipped with: a gas chamber to be measured, into which exhaust gas flows; a pump cell that pumps oxygen into or out of the gas chamber to be measured according to the pump current; and a reference cell of which the reference cell output current detected varies according to the air/fuel ratio inside the gas chamber to be measured. The reference cell is equipped with: a first electrode that is exposed to the exhaust gas in the gas chamber to be measured; a second electrode exposed to a reference atmosphere; and a solid electrolyte layer arranged between the electrodes.

Abstract: In this invention, an EMF oxygen sensor is subjected to an activation process applying unidirectional voltage between an atmosphere electrode and an exhaust electrode thereof. A control device controlling the oxygen sensor in which a voltage was applied with the atmosphere electrode being positive, additionally applies unidirectional voltage between the electrodes to make the atmosphere electrode positive, for example, when the oxygen sensor was used under an environment in which the air-fuel ratio of the internal combustion engine was rich relative to the theoretical air-fuel ratio. Conversely, a control device controlling the oxygen sensor in which a voltage was applied to make the atmosphere electrode negative, additionally applies unidirectional voltage between the electrodes to make the atmosphere electrode negative, for example, when the oxygen sensor was used under an environment in which the air-fuel ratio was lean relative to the theoretical 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: Downstream side air-fuel ratio sensor signal based adaptive air-fuel ratio control. When the air-fuel ratio detected by the downstream side air-fuel ratio sensor is maintained lean unduly, a stuck learning control is performed to decrease a learning value to lower the air-fuel ratio. Adaptive learning value update control is performed based on the downstream side air-fuel ratio sensor signal to increase the learning value when an upstream air-fuel ratio deviates to the rich side and to decrease the learning value when the upstream air-fuel ratio deviates to the lean side. It is judged that the downstream side air-fuel ratio sensor is abnormal when a certain value or more of decrease of the learning value and a certain value or more of increase of the learning value are repeated.

Abstract: A catalyst deterioration determination system determines deterioration of an exhaust gas purification catalyst on the basis of its oxygen storage capacity. The system includes a downstream oxygen concentration sensor having characteristics by which as rich gas components in exhaust gas increase, the oxygen concentration sensor outputs a measurement value of the oxygen concentration corresponding to a richer air-fuel ratio. The system performs a rich shift mode and a lean shift mode based on the measurement value of the oxygen concentration sensor. The rate of change of the exhaust gas air-fuel ratio in at least the lean shift mode is limited to a predetermined rate of change or lower, and the rate of change of the exhaust gas air-fuel ratio in the rich shift mode is set higher than the rate of change of the exhaust gas air fuel ratio in the lean shift mode.

Abstract: A control device for an internal combustion engine comprises an air-fuel ratio control part configured to control the air-fuel ratio of the exhaust gas and a heating control part configured to control the heating of the air-fuel ratio sensors. The heating control part controls the sensor heaters so that the temperature of the upstream air-fuel ratio sensor becomes less than the activation temperature and so that the temperature of the downstream air-fuel ratio sensor becomes the activation temperature or more while the internal combustion engine is stopped by the automatic stop function. The air-fuel ratio control part controls the exhaust air-fuel ratio based on the outputs of the two air-fuel ratio sensors during engine operation and control the air-fuel ratio temporarily based on only the output of the downstream air-fuel ratio sensor after the internal combustion engine has been restarted after automatic stop.

Abstract: An automatically stoppable internal combustion engine comprises an exhaust purification catalyst, an upstream side air-fuel ratio sensor, a downstream side air-fuel ratio sensor, and sensor heaters heating air-fuel ratio sensors. A controller comprises an air-fuel ratio control part and a heating control part. The heating control part controls the temperature of the upstream side air-fuel ratio sensor to the activation temperature or more and the temperature of the downstream side air-fuel ratio sensor to less than the activation temperature during automatic stop of the internal combustion engine. The air-fuel ratio control part controls the air-fuel ratio of the exhaust gas based on the outputs of the two air-fuel ratio sensors during engine operation and controls the air-fuel ratio of the exhaust gas temporarily based on the output of the upstream side air-fuel ratio sensor without using the output of the downstream side air-fuel ratio sensor.

Abstract: In automatic stopping of the internal combustion engine, an electronic control unit controls a heater so that an element temperature of the air-fuel ratio sensor becomes a first temperature. The first temperature is a temperature that is below an activation temperature range in which the air-fuel ratio sensor is activated, and is also below a desorption temperature range in which HC components adsorbed on the air-fuel ratio sensor desorb therefrom. In a case where, after the element temperature of the air-fuel ratio sensor becomes the first temperature, it is estimated that the amount of HC components adsorbed on the air-fuel ratio sensor increases to exceed a first predetermined amount, the electronic control unit controls the heater so that the element temperature of the air-fuel ratio sensor becomes a second temperature. The second temperature is a temperature included in the desorption temperature range.

Abstract: In a limited-current type gas sensor which detects oxygen-containing gas contained in an exhaust gas of an internal combustion engine, the decomposition current value of water (H2O) may be detected, and existence of an abnormality of output characteristics of the sensor may be diagnosed based on its deviation from a reference decomposition current value of water corresponding to the concentration of water contained in the exhaust gas. A NOx sensor and a SOx sensor can also diagnose remarkable and minute abnormalities of output characteristics. In addition, the reference decomposition current value of water may be acquired based on the concentration of water detected by a separate humidity sensor or the decomposition current value of oxygen detected by the limited-current type gas sensor. The reference decomposition current value of water may be corrected based on a decomposition current value of oxygen detected during a fuel cut.

Abstract: A correction device for an air/fuel ratio sensor in the present invention, the sensor issuing an output according to an air/fuel ratio and installed on the downstream from catalyst of the exhaust passage, has air/fuel ratio control means for controlling an air/fuel ratio of an exhaust gas on the upstream side from a catalyst to switch between a rich air/fuel ratio which is richer and a lean air/fuel ratio which is leaner than a stoichiometric air/fuel ratio. Moreover, correction means for correcting an output of the sensor in accordance with a difference between the output of the sensor during a predetermined period during air/fuel ratio control by the air/fuel ratio control means, and a reference output corresponding to a stoichiometric air/fuel ratio, is provided.

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: A correction device for an air/fuel ratio sensor in the present invention, the sensor issuing an output according to an air/fuel ratio and installed on the downstream from catalyst of the exhaust passage, has air/fuel ratio control means for controlling an air/fuel ratio of an exhaust gas on the upstream side from a catalyst to switch between a rich air/fuel ratio which is richer and a lean air/fuel ratio which is leaner than a stoichiometric air/fuel ratio. Moreover, correction means for correcting an output of the sensor in accordance with a difference between the output of the sensor during a predetermined period during air/fuel ratio control by the air/fuel ratio control means, and a reference output corresponding to a stoichiometric air/fuel ratio, is provided.

Abstract: An abnormality diagnosis system of an air-fuel ratio sensor 40 or 41 provided in an exhaust passage of an internal combustion engine and generating a limit current corresponding to an air-fuel ratio, comprises a current detecting part 61 detecting an output current of the air-fuel ratio sensor and an applied voltage control device 60 controlling a voltage applied to the air-fuel ratio sensor. The abnormality diagnosis system applies a voltage inside a limit current region where a limit current is generated and a voltage outside the limit current region to the air-fuel ratio sensor when the air-fuel ratio of the exhaust gas circulating around the air-fuel ratio sensor is made a predetermined constant air-fuel ratio, and judges a type of abnormality occurring at the air-fuel ratio sensor based on an output current of the air-fuel ratio sensor detected by the current detecting part at this time.

Abstract: In an exhaust path of an internal combustion engine, a catalyst, a first air-fuel ratio sensor installed upstream thereof, and a second air-fuel ratio sensor installed downstream thereof are disposed. An air-fuel ratio of the engine is controlled to a rich air-fuel ratio or a lean air-fuel ratio. In a state that is determined as a state where the catalyst stores oxygen to an upper limit after the air-fuel ratio is switched to the lean air-fuel ratio from the rich air-fuel ratio, or a state where the catalyst releases oxygen to a lower limit after the air-fuel ratio is switched to the rich air-fuel ratio from the lean air-fuel ratio, a first output from the first air-fuel ratio sensor, and a second output from the second air-fuel ratio sensor are detected and based on a difference therebetween the output of the first air-fuel ratio sensor is corrected.

Abstract: An oxygen amount (an oxygen storage amount OSA) stored by metal cerium during a storage cycle is obtained based on an output value of an A/F sensor in a time period immediately before an exhaust air-fuel ratio (a downstream side A/F) detected by the A/F sensor shifts to a lean region, and degradation relating to OSC of the three-way catalyst is detected. In the storage cycle, a target air-fuel ratio is set so that an air-fuel ratio of exhaust emission flowing into an S/C changes from rich to lean. Therefore, the downstream side A/F shifts from stoichiometry to the lean region at a time after reaching stoichiometry. When the three-way catalyst degrades, the downstream side A/F shifts to the lean region from stoichiometry at a time. Therefore, the calculated oxygen storage amount OSA becomes extremely smaller as compared with that at a normal time.

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: This control device for an internal combustion engine is equipped with: an air/fuel ratio sensor provided to the exhaust passage of an internal combustion engine; 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 equipped with: a gas chamber to be measured, into which exhaust gas flows; a pump cell that pumps oxygen into or out of the gas chamber to be measured according to the pump current; and a reference cell of which the reference cell output current detected varies according to the air/fuel ratio inside the gas chamber to be measured. The reference cell is equipped with: a first electrode that is exposed to the exhaust gas in the gas chamber to be measured; a second electrode exposed to a reference atmosphere; and a solid electrolyte layer arranged between the electrodes.

Abstract: This control device for an internal combustion engine is equipped with: an air/fuel ratio sensor provided to the exhaust passage of an internal combustion engine; and an engine control device that controls the internal combustion engine on the basis of the sensor output current of the air/fuel ratio sensor. The air/fuel ratio sensor is equipped with: a gas chamber to be measured, into which exhaust gas flows; a reference cell for which the reference cell output current varies according to the air/fuel ratio of the exhaust gas inside the gas chamber to be measured; and a pump cell that, according to the pump current, pumps oxygen into or out of the exhaust gas in the gas chamber to be measured. The reference cell is configured so that the applied voltage, at which the reference cell output current reaches zero, varies according to the air/fuel ratio of the exhaust gas in the gas chamber to be measured.

Abstract: A control device for an internal combustion engine, equipped with: an exhaust purification catalyst provided in the exhaust passage of the internal combustion engine and capable of absorbing oxygen; a downstream air-fuel ratio sensor provided downstream from the exhaust purification catalyst in the direction of the exhaust flow; and an engine control device that controls the internal combustion engine in response to the output from the downstream air-fuel ratio sensor. The downstream air-fuel ratio sensor is configured such that the applied voltage for which the output current is zero changes in response to the exhaust air-fuel ratio, and such that when the exhaust air-fuel ratio equals the theoretical air-fuel ratio and the applied voltage in the downstream air-fuel ratio sensor is increased, the output current increases in conjunction therewith.