Abstract: The purpose of the present invention is to detect deterioration of dead time characteristics of an air-fuel ratio sensor with high accuracy without causing running performance and exhaust performance to worsen. The present invention provides a control device for an engine, characterized by being equipped with: a means for detecting an air-fuel ratio; a means for changing the air-fuel ratio in a predetermined cycle; and a means for sending a notification of an abnormality in the air-fuel ratio detection means or causing at least a portion of the engine control to run in a fail-safe mode when the amplitude of an output signal of the air-fuel ratio detection means at a predetermined frequency is within a predetermined range and the required time or required angle to arrive at a predetermined value of the output signal of the air-fuel ratio detection means from a reference position or reference time point of an engine-related parameter is equal to a predetermined value or higher.

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: The purpose of the present invention is to detect deterioration of dead time characteristics of an air-fuel ratio sensor with high accuracy without causing running performance and exhaust performance to worsen. The present invention provides a control device for an engine, characterized by being equipped with: a means for detecting an air-fuel ratio; a means for changing the air-fuel ratio in a predetermined cycle; and a means for sending a notification of an abnormality in the air-fuel ratio detection means or causing at least a portion of the engine control to run in a fail-safe mode when the amplitude of an output signal of the air-fuel ratio detection means at a predetermined frequency is within a predetermined range and the required time or required angle to arrive at a predetermined value of the output signal of the air-fuel ratio detection means from a reference position or reference time point of an engine-related parameter is equal to a predetermined value or higher.

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: 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.

Abstract: A diagnostic apparatus for exhaust gas clarification apparatus for internal combustion engine diagnoses the individual catalyst independently by an air/fuel ratio sensor mounted before and after the individual catalyst. The individual catalyst is diagnosed by estimating the correlation of the output signals from the air/fuel ratio sensors mounted before and after the individual catalyst. The individual diagnosis operation is performed at distinctive operation regions adequate for their corresponding diagnostic mode. A by-pass route is provided for by-passing the exhaust gas from the upstream catalyst, and a by-pass valve switches the exhaust gas flow into the upstream catalyst or into the by-pass routes. A cross-correlation function calculation valve based upon outputs from air/fuel ratio sensors permits diagnosis of degradation of the overall catalyst.

Abstract: In an apparatus of detecting a combustion state of an internal combustion engine, a combustion parameter value of the engine is calculated on the basis of measurement data concerning an engine speed, the value of the data concerning the engine speed is corrected with a correction value, the correction value is calculated to make the calculated combustion parameter fall within a predetermined range, and the correction value is set to a predetermined value when a predetermined condition is satisfied.

Abstract: A combustion state detection system for an internal combustion engine in which a timing signal associated with the rotation of the crankshaft by a predetermined angle is detected and corrected, and a combustion state parameter is calculated from the timing signal. Further, the deviation of the calculated combustion state parameters for normal combustion is detected between the cylinders, and the correction amount of the timing signal is calculated. A reference cylinder is determined by the means for detecting the deviation. The deviation is detected between the combustion state parameter for normal combustion of the reference cylinder and the cylinder opposed thereto and the combustion state parameter for normal combustion of the remaining cylinders. The correction amount is calculated in such a manner as to control the correction amount to not more than a predetermined value or to zero from the detected deviation.

Abstract: It is intended to detect combustion state of an internal combustion engine over the entire range where positive torque is generated. Time required from a predetermined first crank angle to a second crank angle is measured by detecting a rotation angle of a ring gear or plate with engine speed detecting means 101. Then, a combustion state parameter is calculated from said required time by combustion state detecting means 102 with an established calculation method, and combustion state is determined by combustion state judging means 103. Engine speed correction means 104 determines and feeds back a correction value for the combustion state detecting value to correct the engine speed. At the moment, the correction quantity for correcting the required time is varied so that the normal combustion value of said combustion state parameter is at a predetermined value or less, or within a predetermined range.

Abstract: It is intended to detect combustion state of an internal combustion engine over the entire range where positive torque is generated. Time required from a predetermined first crank angle to a second crank angle is measured by detecting a rotation angle of a ring gear or plate with engine speed detecting means 101. Then, a combustion state parameter is calculated from said required time by combustion state detecting means 102 with an established calculation method, and combustion state is determined by combustion state judging means 103. Engine speed correction means 104 determines and feeds back a correction value for the combustion state detecting value to correct the engine speed. At the moment, the correction quantity for correcting the required time is varied so that the normal combustion value of said combustion state parameter is at a predetermined value or less, or within a predetermined range.