Abstract: Provided is a technology of accurately classifying abnormality in response characteristics of an air-fuel ratio sensors into six deterioration modes. In order to solve the above problems, the present disclosure provides a control device including a microprocessor that detects a response delay of an air-fuel ratio sensor attached to an internal combustion engine, in which the microprocessor includes a target air-fuel ratio change unit configured to change a target air-fuel ratio between lean and rich, and a response delay detection unit configured to detect a respond delay of the air-fuel ratio sensor that occurs in a real air-fuel ratio sensor signal output from the air-fuel ratio sensor when the target air-fuel ratio is changed between the lean and the rich by the target air-fuel ratio change unit.

Abstract: A diagnostic function of a humidity sensor is exposed to the outside and the humidity sensor is likely to deteriorate. An aspect of the present invention includes: a capacitance-voltage conversion circuit which includes a plurality of reference capacitors having different pieces of capacitance and a switch which switches the reference capacitors and outputs a voltage according to the capacitance of a humidity sensor; and a diagnosis unit which compares an output voltage of the capacitance-voltage conversion circuit with a reference voltage obtained from a reference characteristic of the humidity sensor and diagnoses the humidity sensor based on a comparison result. Also, the diagnosis unit changes the output voltage by changing the capacitance of the capacitance-voltage conversion circuit using the switch in a state in which the output voltage of the capacitance-voltage conversion circuit is within a certain range and compares the changed output voltage with the reference voltage.

Abstract: Provided is a technology of accurately classifying abnormality in response characteristics of an air-fuel ratio sensors into six deterioration modes. In order to solve the above problems, the present disclosure provides a control device including a microprocessor that detects a response delay of an air-fuel ratio sensor attached to an internal combustion engine, in which the microprocessor includes a target air-fuel ratio change unit configured to change a target air-fuel ratio between lean and rich, and a response delay detection unit configured to detect a respond delay of the air-fuel ratio sensor that occurs in a real air-fuel ratio sensor signal output from the air-fuel ratio sensor when the target air-fuel ratio is changed between the lean and the rich by the target air-fuel ratio change unit.

Abstract: It is possible to prevent the stability of an engine from deteriorating even when degrees of changes over time of injection characteristics are different in each fuel injection valve. An inter-cylinder air-fuel ratio variation detection unit 1100 calculates an air-fuel ratio variation index (Ind_imb) which indicates a degree of variation in an air-fuel ratio between cylinders from an exhaust air-fuel ratio, engine rotation speed, or the like. Unlike in a case where the air-fuel ratio variation index (Ind_imb) is lower than a set value, when the air-fuel ratio variation index (Ind_imb) is higher than the set value, a fuel injection pulse width limitation unit 2100 sets a (allowable) minimum value (Min_TI) of a fuel injection pulse width so as to be greater. In addition, a fuel injection pulse width calculation unit 3100 calculates fuel injection pulse widths (TI_1, TI_2, TI_3, and TI_4) of cylinders so as not to be lower than the minimum value (Min_TI).

Abstract: A control device of an engine includes means for detecting an efficiency of the engine, means for detecting a combustion stability of the engine, means for detecting an HC discharged quantity, and means for executing a notification. The notification is executed when the efficiency of the engine and the combustion stability of the engine do not fall in a predetermined region A1. The predetermined region A1 is a range of the efficiency of the engine and the combustion stability of the engine. The HC discharged quantity at the time of engine start is a predetermined value or less.

Abstract: It is possible to prevent the stability of an engine from deteriorating even when degrees of changes over time of injection characteristics are different in each fuel injection valve. An inter-cylinder air-fuel ratio variation detection unit 1100 calculates an air-fuel ratio variation index (Ind_imb) which indicates a degree of variation in an air-fuel ratio between cylinders from an exhaust air-fuel ratio, engine rotation speed, or the like. Unlike in a case where the air-fuel ratio variation index (Ind_imb) is lower than a set value, when the air-fuel ratio variation index (Ind_imb) is higher than the set value, a fuel injection pulse width limitation unit 2100 sets a (allowable) minimum value (Min_TI) of a fuel injection pulse width so as to be greater. In addition, a fuel injection pulse width calculation unit 3100 calculates fuel injection pulse widths (TI_1, TI_2, TI_3, and TI_4) of cylinders so as not to be lower than the minimum value (Min_TI).

Abstract: An anomaly in a high-pressure fuel system of an internal combustion engine is diagnosed early on and with high precision, and, further, the anomaly site is identified.

Abstract: Variations in the air-fuel ratio among cylinders are specified as one cause of deterioration in exhaust emissions however the size of the variations in the air-fuel ratio among cylinders detected by the catalyst upstream sensor does not always match the margin of deterioration in exhaust emissions. The objective of the present invention is to detect the deterioration in the exhaust emissions caused due to variations in the air-fuel ratio among cylinders. Deterioration in exhaust emissions due to variations in the air-fuel ratio among engine cylinders is detected based on a means to calculate a specified frequency component A of the catalyst upstream sensor signal; a means to calculate a specified frequency component B of the catalyst downstream sensor signal; and the frequency component A and the frequency component B.

Abstract: The present invention relates to an exhaust performance diagnosis/control device of an engine, and relates specifically to a control device that diagnoses exhaust deterioration at the time of engine start or reduces exhaust gas at the time of start. HC discharged quantity at the time of engine start is diagnosed. The object of the present invention is to provide a means that detects efficiency of the engine and a means that detects combustion stability of the engine, and to detect the HC discharged quantity until activation of a catalyst at the time of engine start based on efficiency of the engine and combustion stability of the engine.

Abstract: An anomaly in a high-pressure fuel system of an internal combustion engine is diagnosed early on and with high precision, and, further, the anomaly site is identified.

Abstract: Disclosed is a diagnostic control apparatus for internal combustion engines capable of accurately diagnosing the presence and extent of air/fuel ratio variations in engine cylinders, even when the system has no part for detecting the air/fuel ratio in each cylinder. The diagnostic control apparatus measures the time required for the crankshaft to rotate to a specified angle for each cylinder; and based on this measured, required time, derives the 0.5 order component as the rotation fluctuation component for each two rotations of the crankshaft per each cylinder or the 1.0 order component as the rotation fluctuation component for each single rotation of the crankshaft; and also counts the number of times the 0.5 order component or 1.0 order component deviates from the preset range in the period set for each cylinder, and diagnoses an error in the output or in the air/fuel ratio for a particular cylinder when that count value exceeds a specified value.

Abstract: In an apparatus for diagnosing an exhaust gas purifying device, a catalyst deterioration level detector 104 detects the deterioration level of a catalyst from a relationship between a catalyst-upstream air-fuel-ratio detector 101 and a catalyst-downstream air-fuel-ratio detector 102. A catalyst-deterioration-level correction section 111 corrects the catalyst deterioration level detected by the catalyst deterioration level detector 104 based on a falling response ratio representing the ratio between a falling response index of the catalyst-upstream air-fuel-ratio detector 101 and a falling response index of the catalyst-downstream air-fuel-ratio detector 102 or based on a rising response ratio representing the ratio between a rising response index of the catalyst-upstream air-fuel-ratio detector 101 and a rising response index of the catalyst-downstream air-fuel-ratio detector 102.

Abstract: To prevent the deterioration of exhaust emissions of an internal combustion engine due to air-fuel ratio variation among multiple cylinders, and to identify an abnormal cylinder during an abnormality of cylinder air-fuel ratio variation. An control apparatus of an internal combustion engine comprising upstream air-fuel ratio detection means for detecting upstream air-fuel ratio of the catalyst that purifies exhaust emissions discharged from multiple cylinders, and configured to control air-fuel ratio of the multiple cylinders based on the upstream air-fuel ratio, wherein the air-fuel ratio variation among the multiple cylinders is increased and the upstream air-fuel ratio is controlled to become rich.

Abstract: Disclosed is a diagnostic control apparatus for internal combustion engines capable of accurately diagnosing the presence and extent of air/fuel ratio variations in engine cylinders, even when the system has no part for detecting the air/fuel ratio in each cylinder. The diagnostic control apparatus measures the time required for the crankshaft to rotate to a specified angle for each cylinder; and based on this measured, required time, derives the 0.5 order component as the rotation fluctuation component for each two rotations of the crankshaft per each cylinder or the 1.0 order component as the rotation fluctuation component for each single rotation of the crankshaft; and also counts the number of times the 0.5 order component or 1.0 order component deviates from the preset range in the period set for each cylinder, and diagnoses an error in the output or in the air/fuel ratio for a particular cylinder when that count value exceeds a specified value.

Abstract: In an apparatus for diagnosing an exhaust gas purifying device, a catalyst deterioration level detector 104 detects the deterioration level of a catalyst from a relationship between a catalyst-upstream air-fuel-ratio detector 101 and a catalyst-downstream air-fuel-ratio detector 102. A catalyst-deterioration-level correction section 111 corrects the catalyst deterioration level detected by the catalyst deterioration level detector 104 based on a falling response ratio representing the ratio between a falling response index of the catalyst-upstream air-fuel-ratio detector 101 and a falling response index of the catalyst-downstream air-fuel-ratio detector 102 or based on a rising response ratio representing the ratio between a rising response index of the catalyst-upstream air-fuel-ratio detector 101 and a rising response index of the catalyst-downstream air-fuel-ratio detector 102.

Abstract: When a fuel cut command is issued, a time required for a crankshaft of each cylinder to rotate through a certain angle is stored in one memory per cylinder. In a stage of engine production, a combustion variation per cylinder is stored in another memory. When fuel is supplied, a particular component is extracted from a value obtained by subtracting the sum of the time required for the rotation in a non-combustion state and the combustion variation from the time required for the rotation corresponding to a cylinder determined to be in a combustion stroke. The occurrence of a misfire is determined when the extracted particular component exceeds a threshold.

Abstract: When a fuel cut command is issued, a time required for a crankshaft of each cylinder to rotate through a certain angle is stored in one memory per cylinder. In a stage of engine production, a combustion variation per cylinder is stored in another memory. When fuel is supplied, a particular component is extracted from a value obtained by subtracting the sum of the time required for the rotation in a non-combustion state and the combustion variation from the time required for the rotation corresponding to a cylinder determined to be in a combustion stroke. The occurrence of a misfire is determined when the extracted particular component exceeds a threshold.

Abstract: A misfire detector is provided that is accurate even in the case of a disturbance due to causes such as driving on a rough road. The misfire detector is equipped with a crankshaft revolution detector to measure the time period required for the crankshaft of an internal-combustion engine to revolve for a given angle. A signal-processor is also provided for detecting the misfiring of the internal-combustion engine by processing the time period. In one embodiment, the misfire detector has two filters having the same sensitivity to the misfire frequency, and differing in the sensitivity to frequencies adjacent to said misfire frequency. It can be determined that a misfire has occurred if the ratio or difference between the outputs of the two filters stays within a fixed range and one or both of the filters have respective outputs exceeding a threshold value.

Abstract: A misfire detector is provided that is accurate even in the case of a disturbance due to causes such as driving on a rough road. The misfire detector is equipped with a crankshaft revolution detector to measure the time period required for the crankshaft of an internal-combustion engine to revolve for a given angle. A signal-processor is also provided for detecting the misfiring of the internal-combustion engine by processing the time period. In one embodiment, the misfire detector has two filters having the same sensitivity to the misfire frequency, and differing in the sensitivity to frequencies adjacent to said misfire frequency. It can be determined that a misfire has occurred if the ratio or difference between the outputs of the two filters stays within a fixed range and one or both of the filters have respective outputs exceeding a threshold value.

Abstract: A combustion state detection system for an internal combustion engine, in which the engine combustion state is detected by the combustion state parameter calculated from a time signal associated with the rotation of the crankshaft by a predetermined angle. The system comprises a device for compensating for the combustion state parameter and a combustion state parameter compensating permitting condition determining device for permitting or inhibiting the execution of the combustion state parameter compensation device.