Abstract: An O2 sensor includes a sensor element using a solid electrolyte layer and a pair of electrodes placed at a position to interpose the solid electrolyte layer, detects an exhaust gas from an internal combustion engine as an object of a detection, and outputs an electromotive force signal depending on an air-fuel ratio of the exhaust gas. The sensor element is connected with a constant current circuit supplying a constant current that is prescribed. A microcomputer conducts an abnormality diagnosis of an output response of the sensor element on the basis of a state of variation in an electromotive force output. Further, when the microcomputer conducts the abnormality diagnosis, the microcomputer restricts a supply of the constant current by the constant current circuit before conducting the abnormality diagnosis.

Abstract: An individual cylinder air-fuel ratio estimation of estimating an air-fuel ratio of an individual cylinder is performed on a sensed value of an air-fuel ratio sensor set in an exhaust gas collection part of an engine, and an individual cylinder air-fuel ratio control of controlling the air-fuel ratio of the individual cylinder is performed in such a way that a variation in the air-fuel ratio between the cylinders becomes small on the basis of an estimated air-fuel ratio of the individual cylinder. Further, it is determined whether or not a misfire of the engine is caused and when it is determined that the misfire of the engine is caused, the individual cylinder air-fuel ratio estimation and the individual cylinder air-fuel ratio control are stopped and an individual cylinder correction value by the individual cylinder air-fuel ratio control is reset.

Abstract: An O2 sensor has a sensor element, which includes a solid electrolyte layer and a pair of electrodes, while the solid electrolyte layer is interposed between the electrodes. The O2 sensor outputs an electromotive force signal in response to an air-to-fuel ratio of exhaust gas of an engine, which serves as a sensing subject. A constant current circuit, which induces a flow of a predetermined constant electric current between the pair of electrodes of a sensor element, and a current sensing arrangement, which senses a current value of an actual electric current that is conducted through the sensor element, are provided. A microcomputer determines whether an abnormality of the constant current circuit is present based on the current value of the electric current, which is sensed with the current sensing arrangement, in a case where the constant current is induced by the constant current circuit.

Abstract: An individual cylinder air-fuel ratio estimation of estimating an air-fuel ratio of an individual cylinder is performed on a sensed value of an air-fuel ratio sensor set in an exhaust gas collection part of an engine, and an individual cylinder air-fuel ratio control of controlling the air-fuel ratio of the individual cylinder is performed in such a way that a variation in the air-fuel ratio between the cylinders becomes small on the basis of an estimated air-fuel ratio of the individual cylinder. Further, it is determined whether or not a misfire of the engine is caused and when it is determined that the misfire of the engine is caused, the individual cylinder air-fuel ratio estimation and the individual cylinder air-fuel ratio control are stopped and an individual cylinder correction value by the individual cylinder air-fuel ratio control is reset.

Abstract: An individual cylinder air-fuel ratio estimation of estimating an air-fuel ratio of an individual cylinder is performed on a sensed value of an air-fuel ratio sensor set in an exhaust gas collection part of an engine, and an individual cylinder air-fuel ratio control of controlling the air-fuel ratio of the individual cylinder is performed in such a way that a variation in the air-fuel ratio between the cylinders becomes small on the basis of an estimated air-fuel ratio of the individual cylinder. Further, it is determined whether or not a misfire of the engine is caused and when it is determined that the misfire of the engine is caused, the individual cylinder air-fuel ratio estimation and the individual cylinder air-fuel ratio control are stopped and an individual cylinder correction value by the individual cylinder air-fuel ratio control is reset.

Abstract: An air-fuel-ratio of each cylinder is estimated based on a detection value of an air-fuel-ratio sensor. An air-fuel-ratio detection timing determination is executed to determine whether a deviation in air-fuel-ratio detection timing exists based on the estimated air-fuel-ratio while the cylinder-by-cylinder air-fuel-ratio control is performed. An observation residual is computed based on the detection value of the air-fuel-ratio sensor and the estimated air-fuel-ratio. When the observation residual is greater than or equal to a specified threshold value, the air-fuel-ratio detection timing determination is prohibited. Therefore, when the observation residual is still large before the estimated air-fuel-ratio of each cylinder is converged, or when the observation residual is still large due to a temporal deterioration in estimating accuracy of the estimated air-fuel-ratio, the air-fuel-ratio detection timing determination can be prohibited.

Abstract: An ECU executes a cylinder-by-cylinder air-fuel-ratio control in which an air-fuel-ratio of each cylinder is estimated based on a detection value of an air-fuel-ratio sensor to adjust the air-fuel-ratio of each cylinder. Further, the ECU computes a learning value of a correction quantity for each cylinder, which is obtained by executing the cylinder-by-cylinder air-fuel-ratio control. Then, the ECU determines whether the estimated air-fuel-ratio has converged according to whether the estimated air-fuel-ratio of each cylinder has been closer to a target value than a specified value for not less than a specified time period. A computation of the learning value is prohibited until the estimated air-fuel-ratio has converged. Therefore, it can be avoided to compute the learning value based on the fuel correction quantity that is obtained when the estimated air-fuel-ratio has not converged yet.

Abstract: An O2 sensor includes a sensor element using a solid electrolyte layer and a pair of electrodes placed at a position to interpose the solid electrolyte layer, detects an exhaust gas from an internal combustion engine as an object of a detection, and outputs an electromotive force signal depending on an air-fuel ratio of the exhaust gas. The sensor element is connected with a constant current circuit supplying a constant current that is prescribed. A microcomputer conducts an abnormality diagnosis of an output response of the sensor element on the basis of a state of variation in an electromotive force output. Further, when the microcomputer conducts the abnormality diagnosis, the microcomputer restricts a supply of the constant current by the constant current circuit before conducting the abnormality diagnosis.

Abstract: An O2 sensor has a sensor element, which includes a solid electrolyte layer and a pair of electrodes, while the solid electrolyte layer is interposed between the electrodes. The O2 sensor outputs an electromotive force signal in response to an air-to-fuel ratio of exhaust gas of an engine, which serves as a sensing subject. A constant current circuit, which induces a flow of a predetermined constant electric current between the pair of electrodes of a sensor element, and a current sensing arrangement, which senses a current value of an actual electric current that is conducted through the sensor element, are provided. A microcomputer determines whether an abnormality of the constant current circuit is present based on the current value of the electric current, which is sensed with the current sensing arrangement, in a case where the constant current is induced by the constant current circuit.

Abstract: An individual cylinder air-fuel ratio estimation of estimating an air-fuel ratio of an individual cylinder is performed on a sensed value of an air-fuel ratio sensor set in an exhaust gas collection part of an engine, and an individual cylinder air-fuel ratio control of controlling the air-fuel ratio of the individual cylinder is performed in such a way that a variation in the air-fuel ratio between the cylinders becomes small on the basis of an estimated air-fuel ratio of the individual cylinder. Further, it is determined whether or not a misfire of the engine is caused and when it is determined that the misfire of the engine is caused, the individual cylinder air-fuel ratio estimation and the individual cylinder air-fuel ratio control are stopped and an individual cylinder correction value by the individual cylinder air-fuel ratio control is reset.

Abstract: An ECU executes a cylinder-by-cylinder air-fuel-ratio control in which an air-fuel-ratio of each cylinder is estimated based on a detection value of an air-fuel-ratio sensor to adjust the air-fuel-ratio of each cylinder. Further, the ECU computes a learning value of a correction quantity for each cylinder, which is obtained by executing the cylinder-by-cylinder air-fuel-ratio control. Then, the ECU determines whether the estimated air-fuel-ratio has converged according to whether the estimated air-fuel-ratio of each cylinder has been closer to a target value than a specified value for not less than a specified time period. A computation of the learning value is prohibited until the estimated air-fuel-ratio has converged. Therefore, it can be avoided to compute the learning value based on the fuel correction quantity that is obtained when the estimated air-fuel-ratio has not converged yet.

Abstract: An air-fuel-ratio of each cylinder is estimated based on a detection value of an air-fuel-ratio sensor. An air-fuel-ratio detection timing determination is executed to determine whether a deviation in air-fuel-ratio detection timing exists based on the estimated air-fuel-ratio while the cylinder-by-cylinder air-fuel-ratio control is performed. An observation residual is computed based on the detection value of the air-fuel-ratio sensor and the estimated air-fuel-ratio. When the observation residual is greater than or equal to a specified threshold value, the air-fuel-ratio detection timing determination is prohibited. Therefore, when the observation residual is still large before the estimated air-fuel-ratio of each cylinder is converged, or when the observation residual is still large due to a temporal deterioration in estimating accuracy of the estimated air-fuel-ratio, the air-fuel-ratio detection timing determination can be prohibited.

Abstract: A deviation amount of a downstream air-fuel ratio sensed with a downstream air-fuel ratio sensor, which senses an air-fuel ratio of exhaust gas downstream of a catalyst, from a target air-fuel ratio is integrated during a period in which the downstream air-fuel ratio continuously shows deviations from the target air-fuel ratio while main feedback control and sub feedback control are performed based on outputs of an upstream air-fuel ratio sensor and the downstream air-fuel ratio sensor respectively. The thus-calculated continuous deviation amount of the downstream air-fuel ratio (deterioration degree of exhaust gas purification rate) is compared with an abnormality determination value to determine existence/nonexistence of an abnormal state where the exhaust gas purification rate is deteriorated by an air-fuel ratio variation among cylinders (i.e., state where control center of main feedback control has shifted).

Abstract: An alcohol concentration sensor detecting alcohol concentration of fuel is provided in a fuel tank or a fuel passage. An alcohol concentration detected at a previous driving of an engine is stored in a backup RAM. When a current alcohol concentration is different from the previous alcohol concentration, a procedure of an abnormality diagnosis is prohibited or invalidated until all of the fuel remaining in the fuel passage is consumed.

Abstract: There is disclosed an alkaline battery including a positive electrode material mixture, a negative electrode, a separator interposed between the positive electrode material mixture and the negative electrode, and an alkaline electrolyte, wherein the positive electrode material mixture includes a first active material comprising nickel oxyhydroxide and a second active material comprising manganese dioxide, the nickel oxyhydroxide includes a ?-type crystal structure, the content of nickel in the nickel oxyhydroxide is not less than 45 wt %, and the average particle diameter on a volume basis of the nickel oxyhydroxide measured with a laser diffraction particle size distribution analyzer is 3 to 20 ?m.

Abstract: A computer calculates an estimated cylinder-intake-air amount based on outputs from an airflow meter and a throttle position sensor, and then calculates a reference cylinder-intake-air amount based on an air-fuel ratio in an exhaust gas and fuel injection amount. An error of the estimated cylinder-intake-air amount is calculated by comparing the reference cylinder-intake-air amount with an estimated cylinder-intake-air amount base value. The error is low-pass filtered. The estimated cylinder-intake-air amount base value is corrected to obtain the final estimated cylinder-intake-air amount.

Abstract: An opening of a waste gate vale is adjusted to control an actual supercharging pressure of intake air. Abnormality in a changing characteristic of the actual supercharging pressure relative to a change in a TCV control duty value can be detected. When an engine is in a steady operation condition, the TCV control duty value is forcibly changed repeatedly by a predetermined amount from 0% to 100%. A deviation between a target supercharging pressure corresponding to the TCV control duty value and an actual supercharging pressure is calculated each time the TCV control duty value is changed by the predetermined amount. This deviation is compared with an abnormality determination value to determine presence/absence of the abnormality in the changing characteristic of the actual supercharging pressure relative to the change in the TCV control duty value.

Abstract: An alcohol concentration sensor detecting alcohol concentration of fuel is provided in a fuel tank or a fuel passage. An alcohol concentration detected at a previous driving of an engine is stored in a backup RAM. When a current alcohol concentration is different from the previous alcohol concentration, a procedure of an abnormality diagnosis is prohibited or invalidated until all of the fuel remaining in the fuel passage is consumed.

Abstract: A computer calculates an estimated cylinder-intake-air amount based on outputs from an airflow meter and a throttle position sensor, and then calculates a reference cylinder-intake-air amount based on an air-fuel ratio in an exhaust gas and fuel injection amount. An error of the estimated cylinder-intake-air amount is calculated by comparing the reference cylinder-intake-air amount with an estimated cylinder-intake-air amount base value. The error is low-pass filtered. The estimated cylinder-intake-air amount base value is corrected to obtain the final estimated cylinder-intake-air amount.

Abstract: An alkaline battery of the present invention includes a positive electrode material mixture including nickel oxyhydroxide. The nickel oxyhydroxide includes a secondary particle with a crystal structure mainly composed of ?-type at least a portion of the surface layer of the secondary particle, and with a crystal structure mainly composed of ?-type in the inner portion of the secondary particle. Based on the present invention, the advantage of the alkaline battery, i.e., excellence in discharge performance under high-load, can be kept and the conventional problem of storage characteristics can be improved.