Abstract: A control device for an internal combustion engine including an upstream cleaning device and a downstream cleaning device that are provided in an exhaust gas passage and a temperature sensor that detects a temperature of exhaust gas between the upstream cleaning device and the downstream cleaning device is provided. The control device includes a first temperature estimating unit configured to estimate a temperature of the downstream cleaning device from the temperature of exhaust gas detected by the temperature sensor and a second temperature estimating unit configured to estimate a temperature of the downstream cleaning device without using the temperature of exhaust gas detected by the temperature sensor. An abnormality determining process for the upstream cleaning device is performed when at least the temperature of the downstream cleaning device estimated by the second temperature estimating unit is equal to or greater than a predetermined threshold value.

Abstract: A control device for an internal combustion engine including an upstream cleaning device and a downstream cleaning device that are provided in an exhaust gas passage and a temperature sensor that detects a temperature of exhaust gas between the upstream cleaning device and the downstream cleaning device is provided. The control device includes a first temperature estimating unit configured to estimate a temperature of the downstream cleaning device from the temperature of exhaust gas detected by the temperature sensor and a second temperature estimating unit configured to estimate a temperature of the downstream cleaning device without using the temperature of exhaust gas detected by the temperature sensor. An abnormality determining process for the upstream cleaning device is performed when at least the temperature of the downstream cleaning device estimated by the second temperature estimating unit is equal to or greater than a predetermined threshold value.

Abstract: A first limit requesting process limits a dither control process of fuel injection valves in such a manner that the absolute value of the difference between the air-fuel ratios of the cylinders becomes smaller when the degree of variation of the injection amounts of the fuel injection valves provided for respective cylinders is great than when the degree of variation is small. A second limit requesting process limits the dither control process in such a manner that the absolute value is smaller when the torque fluctuation amount of the internal combustion engine is great than when the torque fluctuation amount is small. The limiting process limits the dither control process in accordance with one of requests generated by the first limit requesting process and the second limit requesting process that causes the absolute value to be smaller than the other.

Abstract: A controller learns the degree of variation in the injection amount of fuel injection valves provided for respective cylinders when the fuel injection valves are operated to control the air-fuel ratios of the respective cylinders to be equal to each other. A first advancement requesting process causes the request for the ignition timing to be more advanced when the degree of variation is great than when the degree of variation is small. A second advancement requesting process causes the request for the ignition timing to be more advanced when the torque fluctuation amount of the internal combustion engine is than when the torque fluctuation amount is small. The ignition control process controls the ignition timing in accordance with the request of the more advanced one of the first advancement requesting process and the second advancement requesting process.

Abstract: A first limit requesting process limits a dither control process of fuel injection valves in such a manner that the absolute value of the difference between the air-fuel ratios of the cylinders becomes smaller when the degree of variation of the injection amounts of the fuel injection valves provided for respective cylinders is great than when the degree of variation is small. A second limit requesting process limits the dither control process in such a manner that the absolute value is smaller when the torque fluctuation amount of the internal combustion engine is great than when the torque fluctuation amount is small. The limiting process limits the dither control process in accordance with one of requests generated by the first limit requesting process and the second limit requesting process that causes the absolute value to be smaller than the other.

Abstract: A controller learns the degree of variation in the injection amount of fuel injection valves provided for respective cylinders when the fuel injection valves are operated to control the air-fuel ratios of the respective cylinders to be equal to each other. A first advancement requesting process causes the request for the ignition timing to be more advanced when the degree of variation is great than when the degree of variation is small. A second advancement requesting process causes the request for the ignition timing to be more advanced when the torque fluctuation amount of the internal combustion engine is than when the torque fluctuation amount is small. The ignition control process controls the ignition timing in accordance with the request of the more advanced one of the first advancement requesting process and the second advancement requesting process.

Abstract: The fixing structure includes an installation portion having an installation hole into which an installation bolt provided in a chassis is inserted, and a spacer supported movably in horizontal directions perpendicular to an axial direction of the installation bolt inside the installation portion in a non-fastened state between the installation bolt and the nut. The spacer has a collar portion that is placed between an inner circumferential surface of the installation hole and an outer circumferential surface of the installation bolt and makes contact with the chassis and the washer in the axial direction of the installation bolt in a fastened state between the installation bolt and the nut, and a flange portion formed to protrude outward from the outer circumference of the collar portion and supported movably in the horizontal directions in a non-fastened state. The flange portion is fixed inside the installation portion in the fastened state.

Abstract: A fixing structure includes an attaching portion, a nut, and a spacer. The attaching portion has an attaching hole through which an attaching bolt provided to a vehicle body is inserted. The nut fixes the attaching portion to the vehicle body by being tightened to the attaching bolt with a washer interposed between the nut and the attaching portion. The spacer is disposed between an inner circumferential surface of the attaching hole and an outer circumferential surface of the attaching bolt, and is in contact with the vehicle body and the washer in an axial direction of the attaching bolt in a state where the attaching bolt and the nut are tightened. The spacer has an opening on a cylindrical side surface thereof and is capable of rotating around the axial direction of the attaching bolt in a state where the attaching bolt is inserted into the opening.

Abstract: A control device of an internal combustion engine according to the present invention executes air-fuel ratio control based on an output of an air-fuel ratio sensor provided at an upstream side of a catalyst, with correction based on an output of an oxygen sensor at a downstream side of the catalyst. When it is determined that a degree of an output tendency in a predetermined lean region is not less than a predetermined lean degree, and that a degree of an output tendency in a predetermined rich region is less than a predetermined rich degree based on lean tendency and rich tendency values representing output tendencies of the oxygen sensor, a limit is set to the correction in a direction to more suppress enriching of an air-fuel ratio as a degree is larger in which the output of the oxygen sensor is shifted to a lean side.

Abstract: A fixing structure includes an attaching portion, a nut, and a spacer. The attaching portion has an attaching hole through which an attaching bolt provided to a vehicle body is inserted. The nut fixes the attaching portion to the vehicle body by being tightened to the attaching bolt with a washer interposed between the nut and the attaching portion. The spacer is disposed between an inner circumferential surface of the attaching hole and an outer circumferential surface of the attaching bolt, and is in contact with the vehicle body and the washer in an axial direction of the attaching bolt in a state where the attaching bolt and the nut are tightened. The spacer has an opening on a cylindrical side surface thereof and is capable of rotating around the axial direction of the attaching bolt in a state where the attaching bolt is inserted into the opening.

Abstract: The fixing structure includes an installation portion having an installation hole into which an installation bolt provided in a chassis is inserted, and a spacer supported movably in horizontal directions perpendicular to an axial direction of the installation bolt inside the installation portion in a non-fastened state between the installation bolt and the nut. The spacer has a collar portion that is placed between an inner circumferential surface of the installation hole and an outer circumferential surface of the installation bolt and makes contact with the chassis and the washer in the axial direction of the installation bolt in a fastened state between the installation bolt and the nut, and a flange portion formed to protrude outward from the outer circumference of the collar portion and supported movably in the horizontal directions in a non-fastened state. The flange portion is fixed inside the installation portion in the fastened state.

Abstract: An air-fuel ratio control apparatus for an internal combustion engine is provided. A controller is programmed to perform correction amount guard control allowing adjustment of a correction amount by setting a limit on the correction amount when an appearance frequency of a state where an output value from a downstream sensor is leaner than a predetermined value is equal to or higher than a predetermined value. When a state where the output value from the downstream sensor is leaner than the predetermined value lasts for a duration equal to or longer than a predetermined time, an incorporation speed at which, during learning control, the correction amount for sub feedback control is incorporated into a learning value is set to a larger value that when the duration is shorter than the predetermined time, and performance of the correction amount guard control is suppressed until the learning control is completed.

Abstract: An abnormality detecting device of an internal combustion engine according to the present invention includes a sensor nick abnormality detecting unit configured to detect a nick abnormality in a detecting element of a downstream side sensor which is provided in a downstream side of an exhaust gas purifying catalyst in an exhaust passage and generates an output corresponding to an oxygen concentration in exhaust gas, on the basis of a matter that a distribution of an output of the downstream side sensor is biased to an area in which the air-fuel ratio is leaner than a theoretical air-fuel ratio, and an inhibiting unit configured to inhibit detection of the nick abnormality of the detecting element by the sensor nick abnormality detecting unit in the case that an intake air amount exceeds a predetermined amount.

Abstract: An air-fuel ratio control apparatus for an internal combustion engine is provided. A controller is programmed to perform correction amount guard control allowing adjustment of a correction amount by setting a limit on the correction amount when an appearance frequency of a state where an output value from a downstream sensor is leaner than a predetermined value is equal to or higher than a predetermined value. When a state where the output value from the downstream sensor is leaner than the predetermined value lasts for a duration equal to or longer than a predetermined time, an incorporation speed at which, during learning control, the correction amount for sub feedback control is incorporated into a learning value is set to a larger value that when the duration is shorter than the predetermined time, and performance of the correction amount guard control is suppressed until the learning control is completed.

Abstract: A control device of an internal combustion engine according to the present invention executes air-fuel ratio control based on an output of an air-fuel ratio sensor provided at an upstream side of a catalyst, with correction based on an output of an oxygen sensor at a downstream side of the catalyst. When it is determined that a degree of an output tendency in a predetermined lean region is not less than a predetermined lean degree, and that a degree of an output tendency in a predetermined rich region is less than a predetermined rich degree based on lean tendency and rich tendency values representing output tendencies of the oxygen sensor, a limit is set to the correction in a direction to more suppress enriching of an air-fuel ratio as a degree is larger in which the output of the oxygen sensor is shifted to a lean side.

Abstract: A control device of an internal combustion engine according to the present invention has units configured to inject fuel at a first predetermined ratio from first and second fuel injection valves which are provided in each of cylinders to calculate a first value indicating a degree of variation in air-fuel ratios between the cylinders based on a output of the engine, and inject fuel at a second predetermined ratio therefrom to calculate a second value in the same manner. Furthermore, the control device has a unit configured to select one mode from modes relating to abnormality in the first fuel injection valve or the second fuel injection valve on the basis of the first and second values, and calculate a value indicating the degree of the variation in the air-fuel ratios between the cylinders, thereby calculating a fuel amount of the basis of them.

Abstract: A control device of an internal combustion engine according to the present invention has units configured to inject fuel at a first predetermined ratio from first and second fuel injection valves which are provided in each of cylinders to calculate a first value indicating a degree of variation in air-fuel ratios between the cylinders based on a output of the engine, and inject fuel at a second predetermined ratio therefrom to calculate a second value in the same manner. Furthermore, the control device has a unit configured to select one mode from modes relating to abnormality in the first fuel injection valve or the second fuel injection valve on the basis of the first and second values, and calculate a value indicating the degree of the variation in the air-fuel ratios between the cylinders, thereby calculating a fuel amount of the basis of them.

Abstract: An abnormality detecting device of an internal combustion engine according to the present invention includes a sensor nick abnormality detecting unit configured to detect a nick abnormality in a detecting element of a downstream side sensor which is provided in a downstream side of an exhaust gas purifying catalyst in an exhaust passage and generates an output corresponding to an oxygen concentration in exhaust gas, on the basis of a matter that a distribution of an output of the downstream side sensor is biased to an area in which the air-fuel ratio is leaner than a theoretical air-fuel ratio, and an inhibiting unit configured to inhibit detection of the nick abnormality of the detecting element by the sensor nick abnormality detecting unit in the case that an intake air amount exceeds a predetermined amount.

Abstract: An inter-cylinder air-fuel ratio imbalance abnormality determination device includes a catalyst provided in an exhaust passage of a multi-cylinder internal combustion engine; a pre-catalyst sensor; a post-catalyst sensor; an air-fuel ratio control unit that performs main air-fuel ratio control based on an output of the pre-catalyst sensor and auxiliary air-fuel ratio control based on an output of the post-catalyst sensor; a control amount calculation unit that calculates a control amount in the auxiliary air-fuel ratio control based on the output of the post-catalyst sensor; a revolution speed variation detection unit that detects a revolution speed variation of the engine; an abnormality determination unit that performs imbalance abnormality determination for determining whether an inter-cylinder air-fuel ratio imbalance abnormality has occurred based on a detected value of the revolution speed variation; and a guard range reduction unit that reduces a guard range of the control amount during the imbalance a

Abstract: An apparatus and method for detecting an abnormal air-fuel ratio variation between cylinders of a multi-cylinder internal combustion engine in which the output of an air-fuel ratio sensor is acquired at each sampling interval, a parameter correlated with the degree of fluctuation of the sensor output is calculated from a plurality of the acquired sensor outputs, and the presence or absence of the abnormal air-fuel ratio variation between cylinders is determined by comparing the parameter with a determination value. A cylinder air amount is estimated at each sampling interval. Every time the air-fuel ratio sensor output is acquired, the value of the cylinder air amount at the point earlier, by a transport delay time, than the point of the acquisition is determined based on the time-series data, and a corresponding determination value corresponding thereto is calculated. The determination value is determined based on a plurality of the calculated corresponding determination values.