JP2004036464A5 - - Google Patents

Claims (20)

An exhaust purification catalyst that is provided in an exhaust passage of the internal combustion engine and purifies harmful components in the exhaust;
An inlet gas sensor for detecting a gas component in the exhaust upstream of the exhaust purification catalyst;
An outgas sensor for detecting a gas component in the exhaust downstream of the exhaust purification catalyst;
An operating state detecting means for detecting an operating state of the internal combustion engine;
Means for determining whether or not a rich air-fuel ratio exhaust gas or an exhaust gas containing unburned fuel is in an operating state in which the catalyst flows
When it is determined that the rich air-fuel ratio exhaust gas and the exhaust gas containing unburned fuel are not in an operation state in which the exhaust gas flows into the catalyst, the input gas sensor or the output gas sensor based on the detection values of the input gas sensor and the output gas sensor Deterioration determination means for determining at least one of the deterioration;
A deterioration determination device for a gas sensor, comprising: 2. The gas sensor deterioration determination apparatus according to claim 1 , wherein the deterioration determination unit determines deterioration based on an output difference between the input gas sensor and the output gas sensor. The deterioration determining means, prior to when the output difference between the filling gas sensor and the output gas sensor is greater than a first predetermined value, according to claim 1 or any one of the sensors and judging that the deterioration 2. A gas sensor deterioration determination apparatus according to 2. And a correction value calculating means for calculating a correction value of at least one of the input gas sensor and the output gas sensor when an output difference between the input gas sensor and the output gas sensor is equal to or less than a first predetermined value. The deterioration determination device for a gas sensor according to claim 2 or 3 . The correction value calculation means outputs at least one of the input gas sensor and the output gas sensor when an output difference between the input gas sensor and the output gas sensor is larger than a second predetermined value and smaller than the first predetermined value. The gas sensor deterioration determination device according to claim 4 , wherein the correction value is calculated. 6. The output correction unit according to claim 4, further comprising: an output correction unit that performs output correction based on one of the input gas sensor and the output gas sensor and the other based on the correction value calculated by the correction value calculation unit. Gas sensor deterioration judgment device. Determining exhaust that contains the exhaust or unburned fuel rich air-fuel ratio is whether or not the operating state flowing into the catalyst from claim 1, characterized in that it is carried out in a combustion operation of the internal combustion engine 6 The deterioration judgment apparatus of the gas sensor in any one of. A fuel supply means for supplying fuel to the internal combustion engine; and a fuel supply stop means for stopping the fuel supply by the fuel supply means. The correction value calculating means is configured to supply fuel by the fuel supply stop means. 8. The gas sensor deterioration determination apparatus according to claim 7 , wherein the other output signal is corrected based on one output signal of the inlet gas sensor or the outlet gas sensor when the gas sensor is stopped. Exhaust pressure detection means for detecting the exhaust pressure is further provided, and the correction value calculation means corrects the output of the inlet gas sensor or the outlet gas sensor in accordance with the exhaust pressure detected by the exhaust pressure detector. A gas sensor deterioration determination device according to any one of claims 1 to 8 . The correction value calculating means is configured to determine whether a change due to an exhaust pressure in an output value of the inlet gas sensor or the outlet gas sensor from a relationship between a pressure of exhaust gas obtained in advance and an output change amount of the inlet gas sensor or the outlet gas sensor due to the pressure. The deterioration determination device for a gas sensor according to claim 9 , wherein the correction value is calculated while obtaining the change and removing the change. When the exhaust gas containing the rich air-fuel ratio and the exhaust gas containing unburned fuel is not in an operation state in which the exhaust gas flows into the catalyst, the input gas sensor or the output gas sensor is based on the detected values of the input gas sensor upstream of the exhaust purification catalyst and the output gas sensor downstream of the catalyst A method for determining the deterioration of a gas sensor, characterized by determining at least one of the deterioration. The deterioration determination method for a gas sensor according to claim 11 , wherein deterioration is determined based on an output difference between the input gas sensor and the output gas sensor. 13. The gas sensor according to claim 11 , wherein one of the sensors is determined to be deteriorated when an output difference between the inlet gas sensor and the outlet gas sensor is larger than a first predetermined value. Degradation judgment method. If the output difference between the entering-gas sensor and the output gas sensor is equal to or less than the first predetermined value, according to claim 12 or 13, characterized in that at least one of correction of the output of the incoming gas sensor or out gas sensor Of gas sensor deterioration judgment. When an output difference between the inlet gas sensor and the outlet gas sensor is larger than a second predetermined value and smaller than the first predetermined value, the output of at least one of the inlet gas sensor or the outlet gas sensor is corrected. The deterioration determination method for a gas sensor according to claim 14 . 16. The method of determining deterioration of a gas sensor according to claim 14 or 15 , wherein one of the inlet gas sensor and the outlet gas sensor is used as a reference, and the other is output corrected. 17. The gas sensor deterioration determination method according to claim 11 , wherein the deterioration determination is performed during a combustion operation of the internal combustion engine. 18. The gas sensor deterioration determination method according to claim 17 , wherein the other output signal is corrected based on one output signal of the inlet gas sensor or the outlet gas sensor when fuel supply is stopped. 19. The gas sensor deterioration determination method according to claim 11, wherein an output of the inlet gas sensor or the outlet gas sensor is corrected in accordance with an exhaust pressure. A change due to the exhaust pressure in the output value of the inlet gas sensor or the outlet gas sensor is obtained from a relationship between the pressure of the exhaust gas determined in advance and an output change amount of the inlet gas sensor or the outlet gas sensor due to the pressure. The gas sensor deterioration determination method according to claim 19 , wherein the correction value is calculated while removing the gas.