Abstract: A map creating method for nozzle vanes includes performing an imbalance operation as many times as the number of the cylinders while changing the specific cylinder, creating air-fuel ratio data indicating changes in the air-fuel ratio during the imbalance operation, calculating an air-fuel ratio fluctuation amount for each of pieces of the air-fuel ratio data, determining whether a specific condition is met, the specific condition being that a minimum value among the air-fuel ratio fluctuation amounts is greater than or equal to a first determination value and a difference between the minimum value and a maximum value among the air-fuel ratio fluctuation amounts is less than or equal to a second determination value, and storing, as an opening degree map, the opening degree of the nozzle vanes meeting the specific condition in association with the engine operating state.

Abstract: The invention relates to a method for monitoring at least one aircraft engine, said method including an acquisition (100) according to the first and second sets of measurements of respectively endogenous and exogenous variables. The method also includes: a normalization (200) of the measurements of the first set relative to the measurements of the second set, a generation (300) of a current model representative of the evolution of the behavior of the engine based on the normalized measurements, a detection (400) of potential abnormality in the behavior of the engine based on a comparison of the current model with a reference model, a generation (500) of a maintenance message, a transmission (600) of said ground message, the acquisition, normalization, generation of a current model, the detection and generation of a maintenance message being made on board the aircraft.

Abstract: A rotor support member includes: a tubular portion having a tubular shape extending along an axial direction and supporting a rotor of a rotary electric machine; and a flange portion provided to extend along a radial direction on an inner side in radial direction with respect to tubular portion at a position adjacent to a first engagement device on a first side in the axial direction, and connected to tubular portion. The flange portion includes a cylinder forming portion protruding to first side in the axial direction so as to form a cylinder portion on which a first piston portion of the first engagement device slides. A rotation sensor includes a rotating body supported by an outer peripheral surface of cylinder forming portion on an outer side in the radial direction, and a fixed body disposed on the outer side in the radial direction with respect to the rotating body.

Abstract: An exemplary embodiment may include a control hub configured to receive data from an emissions analyzer and a leak detection camera. The emissions analyzer may detect levels of various gases and relay such information to the control hub. In an exemplary embodiment, the emissions analyzer may purge after every test to ensure longevity and accuracy. A leak detection camera may implement quantifying optical gas imaging in order to continuously monitor for fugitive leaks on a compressor package. If a leak is detected, it may be logged and the user or an operating group may be alerted.

Abstract: A remote controller, a remote-control system and a control method thereof are provided. The remote controller includes a motion sensing circuit and a wireless communication circuit electrically connected to the motion sensing circuit. The motion sensing circuit determines whether or not a motion of the remote controller complies with one of multiple reference motions. When the motion of the remote controller complies with one of the reference motions, the wireless communication circuit is switched from a sleep state to a working state. The wireless communication circuit that is in the working state determines whether or not a received signal strength indication between the remote controller and a controlled device is greater than or equal to a strength threshold. When the received signal strength indication is less than the strength threshold, the wireless communication circuit is switched from the working state to the sleep state.

Abstract: A method of processing an image using a camera of a vehicle includes: a first operation of controlling a road wheel of the vehicle according to an imaging mode selected by a user from among a plurality of imaging modes, and a second operation of generating an image according to the imaging mode selected by the user by using the camera while the road wheel of the vehicle is controlled.

Abstract: Methods and systems are provided for balancing a plurality of fuel injectors. In one example, a method includes adjusting port-fuel injecting parameters in response to a learned direct injector fueling error.

Abstract: An Internet of Things (IoT) gateway integrated into a real-time monitoring system for skid-mounted natural gas compression systems. The IoT gateway enables remote monitoring, troubleshooting, and diagnosing of natural gas compression systems by providing access to cellular and satellite communication networks for communicating operational data to one or more remote servers. The IoT gateway can be configured to select a communication network based on an order of priority and other various criteria. The order of priority and the selection criteria may be updated over the air. The IoT gateway can be further configured to receive and relay software and other updates to one or more components of the natural gas compression system. The IoT gateway is configured to meet various regulatory compliance standards and is explosion proof.

Abstract: A state estimation device for an internal combustion engine includes: a storage device that stores mapping data, the mapping data being data defining a mapping that takes as an input an internal combustion engine state variable and that generates as an output an estimated value for estimating the state of the internal combustion engine; and an execution device that executes an acquisition process of acquiring the internal combustion engine state variable and an estimation process of calculating the estimated value based on the output of the mapping. The mapping data is data learned by machine learning. When the estimated value is out of an acceptable range, the execution device executes a guard process of adjusting the estimated value to a value close to or within the acceptable range. When executing the guard process, the execution device calculates the value after the guard process as the estimated value.

Abstract: A power-feed connector disconnection device includes an index value detector, a starting intention determiner, and a lock-releasing unit. The index value detector detects an index value that correlates with a starting intention of a driver to start a vehicle when a power-feed connector is coupled to a power-receiving connector of the vehicle. The starting intention determiner determines a presence or absence of the starting intention of the driver based on the index value detected by the index value detector when the power-feed connector is coupled to the power-receiving connector of the vehicle. The lock-releasing unit is provided in the power-receiving connector and releases a lock between the power-receiving connector and the power-feed connector when the starting intention determiner determines that the driver has the starting intention.

Abstract: An engine diagnostic system is provided for diagnosing a deterioration degree of an engine mounted on a vehicle. The engine diagnostic system learns, as a knock learning value, a maximum advancement amount of an ignition timing that reduces knocking. A database stores time-series data of the knock learning value of the engine for each individual engine. The knock learning value is acquired from each of a plurality of vehicles of the same model. An evaluation process computes an evaluation value indicating the deterioration degree of a designated engine using the time-series data of the knock learning value of each engine stored in the database.

Abstract: An engine system includes a combustion chamber including a cylinder, a fuel supply that supplies fuel including gasoline into the combustion chamber, circuitry configured to predict a knock will occur in the combustion chamber, and a fluid injector that injects a fluid into the combustion chamber. Further, there is circuitry configured to suppress a knock by instructing the fluid injector, when the knock is predicted to occur by the circuitry configured to predict, to inject the fluid into the combustion chamber within a period before a burned mass fraction reaches 50% after a start of combustion.

Abstract: A motor controller for an electric motor is provided, including a drive circuit and a processor. The drive circuit regulates power supplied to a stator of the electric motor to turn a rotor and blower to generate an airflow. The processor receives an air density, an airflow rate demand, and at least one of a measured torque and a measured speed of the electric motor. The processor computes one of a torque set point and a speed set point for the electric motor using an airflow algorithm and based on the air density, the airflow rate demand, and the at least one of the measured torque and the measured speed. The processor controls the drive circuit based on the one of the torque set point and the speed set point to supply electrical power to the electric motor and to operate the blower to generate the airflow.

Abstract: A motor failure diagnosis system includes: a motor having a rotating shaft and a bearing that receives the rotating shaft; a vibration sensor capable of detecting a vibration of the motor when the rotating shaft is a rotation state; the date information output unit capable of outputting date information; a vibration information storage unit that stores the vibration information detected by the vibration sensor and the date information output by the date information output unit in correlation; and a failure date identifying unit that identifies the date on which a failure occurred in the bearing of the motor on the basis of the vibration information and the date information stored in the vibration information storage unit.

Abstract: An apparatus for diagnosing a failure of a sensor may include an engine; an intake manifold; a turbocharger including a turbine rotated by exhaust gas of the combustion chamber and a compressor provided at the intake line, rotated in connection with the turbine, and compressing external air; a map sensor measuring a pressure of a front end portion of the compressor; a differential pressure sensor measuring a differential pressure of front and rear end portions of an EGR valve provided at an EGR apparatus; an operation information detecting device measuring operation information including an engine speed and a load; and a controller determining whether an exhaust gas pressure is constant from the operation information and comparing a change amount of the differential pressure sensor signal and a change amount of the map sensor signal in the condition that the exhaust gas pressure is constant to diagnose a failure of the differential pressure sensor.

Abstract: Methods and systems are provided for enabling a transfer function of a direct injector and a port injector, each fueling an engine cylinder, to be accurately learned. During selected conditions, the direct injected fuel fraction may be actively changed from a target fraction to one of an upper and lower limit of the direct injector so as to provide a measurable air-fuel ratio error. Fueling errors for the distinct fuel injectors is then learned based on the measured air-fuel ratio error relative to the actively changed fuel fraction.

Abstract: The present disclosure provides a method and an apparatus for monitoring a status of a terminal compressor. The method includes: obtaining a working status parameter of a compressor in a first terminal; judging whether the working status parameter falls in a preset range; if the working status parameter does not fall in the preset range, determining that an abnormality of the compressor occurs; and analyzing a reason for the abnormality and transmitting preset information to a second terminal that controls the first terminal.

Abstract: Methods and systems are provided for reducing port injection fuel errors by selectively reactivating a direct fuel injector. Responsive to an increase in driver demand received while delivering fuel to a cylinder via port injection only, wherein the increase in driver demand is received late in the port injection window, the port injection error is addressed by reactivating a direct injector on the same engine cycle and delivering at least a portion of the fuel mass corresponding to the error via the direct injector. Additionally, a portion of the fuel mass may be delivered by the port injector on the same engine cycle by extending the end of injection timing, if possible.

Abstract: In a transmission with a lockup clutch, in a case where zero-slip control of the lockup clutch is not established (converged) within a predetermined time, a sweep increase of a lockup clutch hydraulic pressure starts at an increase rate smaller than a normal increase rate in a case where the zero-slip control is established within the predetermined time, the increase rate until the end of the sweep increase is set to be equal to or less than the normal increase rate, and in addition, a hydraulic pressure at the time of the end of the sweep increase is set to be equal to or greater than a hydraulic pressure in a case where the zero-slip control is established within the predetermined time. With such control, in a case where the zero-slip state is not brought, suppressing the occurrence of shock when complete engagement is carried out.

Abstract: Systems and methods for improving fuel injection of an engine that includes a cylinder receiving fuel from two different fuel injectors is disclosed. In one example, fueling errors for each of the two fuel injectors are determined based on fractions of fuel supplied by the two fuel injectors during different engine operating conditions.

Abstract: A method for diagnosing an exhaust gas recirculation (EGR) system includes: a setting step of setting a temperature map with respect to a temperature at an outlet side of an EGR line for an output value reflecting a driving state of a vehicle in a state in which an EGR valve is closed; a measuring step of measuring the temperature at the outlet side of the EGR line at the time of an operation of the EGR system; and a diagnosing step of diagnosing that a fault has been generated in an EGR system when the measured temperature at the outlet side of the EGR line is equal to or less than a reference value set in the temperature map.

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: The abnormality of an NH3 sensor is judged highly accurately.

Abstract: The invention relates to a control and regulation method for an internal combustion engine (1) having a common rail system wherein the rail pressure (pCR) is regulated in normal operation in that an offset of the rail pressure (pCR) is calculated and a PWM signal (PWM) is determined for activating the control process via a pressure controller based on the offset, wherein a load rejection when the rail pressure (pCR) exceeds a limit and wherein upon recognition of the load rejection, the rail pressure (pCR) is controlled in that the PWM signal (PWM) is temporarily set to a PWM value that is higher compared to normal operation via a PWM parameter. The invention is characterized in that the threshold for activation of the temporary PWM parameter is calculated in dependence on the gradient of a power-determining signal.

Abstract: In an engine having a plurality of cylinders in which a plurality of fuel injection valves are provided respectively, fuel is injected at a predetermined injection ratio, and an abnormality of air-fuel ratio variation is detected. If a fuel injection amount of at least one of the plurality of the fuel injection valves is smaller than a predetermined reference value, the fuel injection amount is increased so as to become equal to or larger than the reference value.

Abstract: Disclosed is a common rail fuel injection control apparatus that is used in an engine that drives power equipment, an actual measurement temperature difference that is a difference between a pre-pressurization temperature of the fuel and a post-pressurization release temperature of the fuel is obtained, and it is determined that a pressure sensor is failed when an absolute value of a difference between a representative temperature difference set in advance as a difference between the pre-pressurization temperature of the fuel and the post-pressurization release temperature of the fuel, and the actual measurement temperature difference exceeds a predetermined threshold value.

Abstract: An abnormality determining apparatus includes an air-fuel ratio controller, an output change period parameter calculator, an output change amount extremum calculator, and an abnormality determining device. The abnormality determining device is configured to determine an abnormality of an air-fuel ratio sensor based on a relationship between an output change period parameter and an output change amount extremum.

Abstract: An air-fuel ratio imbalance among cylinders determining apparatus according to the present invention obtains an output Vabyfs of an air-fuel ratio sensor disposed at a portion downstream of an exhaust gas aggregated portion of an exhaust gas passage, and obtains a second-order differential value d2AF (a change rate of a change rate of a detected air-fuel ratio abyfs) of a detected air-fuel ratio abyfs represented by the air-fuel ratio sensor output Vabyfs. The imbalance determining apparatus determines that an air-fuel ratio imbalance state among cylinders is occurring when a detected air-fuel ratio second-order differential corresponding value (for example, a second-order differential value d2AF per se) obtained in accordance with the second-order differential value d2AF is larger than a first threshold value.

Abstract: Provided is a control apparatus for an internal combustion engine, which can favorably suppress an occurrence of abnormal combustion regardless of its operational conditions. An occurrence probability of abnormal combustion of the internal combustion engine (10) is obtained on the basis of a fuel dilution index. An expected value I of the number of occurrences of abnormal combustion per a predetermined time period is calculated on the basis of the occurrence probability of abnormal combustion. The upper limit value of a torque generated by the internal combustion engine (10) is limited low so that the expected value I does not exceed a predetermined tolerable value.

Abstract: A control system for a vehicle includes an error detection module and a remedial control module. The error detection module detects whether an accelerator of the vehicle is stuck is based on vehicle speed, a position of the accelerator, and one of a pressure applied to a brake of the vehicle and a status of a parking brake of the vehicle. The remedial control module, when the accelerator is stuck, at least one of resets the position of the accelerator and decreases torque output of a powertrain system.

Abstract: An apparatus for controlling an internal combustion engine executes air-fuel ratio feedback control based on a detection result of an exhaust gas sensor and when the engine is shut down, stops energization of a heater of the exhaust gas sensor at a predetermined timing after shutdown of the engine, heater control of the exhaust gas sensor is executed, which is suitable for a case in which shutdown time of the engine is set long, and thus the exhaust gas sensor is protected from thermal shock. The control apparatus sets timing for stopping energization of a heater of an exhaust gas sensor after shutdown of the engine, to a point in time when a predetermined time set based on outside air temperature has elapsed, or a point in time when cooling water temperature of the engine has dropped to a predetermined temperature.

Abstract: A system according to the principles of the present disclosure includes an error period module and a sensor diagnostic module. The error period module determines an error period based on an amount of time that a first air/fuel ratio and a desired air/fuel ratio are different. A first oxygen sensor generates a first signal indicating the first air/fuel ratio. The sensor diagnostic module diagnoses a fault in the first oxygen sensor when the error period is greater than a predetermined period.

Abstract: An evaporative emission control system for a turbocharged engine. The system includes a fuel vapor canister in fluid communication with an intake manifold of the engine, a purge valve positioned between the intake manifold and the canister, a bypass valve positioned between the purge valve and the canister and connected to the atmosphere, and an evaporative system integrity monitor operable to seal the canister from the atmosphere when the engine is off. In operation, the monitor is closed so as to seal the canister from the atmosphere, the purge valve is closed so as to isolate the intake manifold from the canister, and the bypass valve is opened so as to connect the canister to the atmosphere. Proper operation of the monitor is determined if the monitor toggles from closed to open when a vacuum in the fuel vapor canister reaches a predetermined level.

Abstract: A method for monitoring the enabling of a system which is assigned to an internal combustion engine, in which the readiness for operation of the system is dependent on an operating temperature, is characterized in that a fault in the enabling of the system is inferred (106) if operation of the system cannot be detected on expiry of a predeterminable time period after the starting of the internal combustion engine or on the recurrence of readiness for operation.

Abstract: A dual fuel common rail system may be operated in a regular mode in which a relatively large charge of gaseous fuel is ignited by compression igniting a relatively small injection quantity of liquid diesel fuel. The dual fuel system may be operated in a single fuel limp home mode in which liquid diesel fuel is injected at higher pressures. When transitioning from the single fuel limp home mode to the dual fuel regular mode, accumulated leaked liquid fuel in the gaseous nozzle chamber of each fuel injector is purged and burned in the respective engine cylinder.

Abstract: Methods and systems are provided for fuel systems including a gaseous fuel. Temporary flow restrictions in the fuel line of a first gaseous fuel may be addressed by temporarily shifting to cylinder operation with a second liquid fuel. Upon resumption of first fuel operation, if the flow restriction persists, a diagnostic code may be set and cylinder operation with the second fuel may be restarted.

Abstract: An apparatus for detecting imbalance abnormality in an air-fuel ratio between cylinders in a multi-cylinder internal combustion engine according to the present invention increases a fuel injection quantity to a predetermined target cylinder to detect imbalance abnormality in an air-fuel ratio between cylinders at least based upon a rotation variation of the target cylinder after increasing the fuel injection quantity. The increase in the fuel injection quantity is carried out in the middle of performing the post-fuel-cut rich control. Since timing of the post-fuel cut rich control is used to increase the fuel injection quantity, the exhaust emission deterioration due to abnormality detection execution can be prevented as much as possible.

Abstract: Systems and methods for isolating a performance anomaly within one or more line replaceable units (LRUs) on a gas turbine engine by monitoring the start up transient are presented. The system comprises a set of sensors, an anomaly detector and a fault isolation reasoner. Each sensor of the set monitors at least one operating parameter of at least one engine component. The anomaly detector is configured to detect an anomaly in a component by comparing a particular value of an operating parameter to a base line value of that parameter. The specific cause of the startup anomaly is isolated utilizing a set of component reasoners that is based on the nature of the detected anomaly. The key events during the engine startup are identified by the combination of monitoring physically relevant phases of a startup and monitoring the engine control schedule. The values at these key events are used for comparing at the anomaly detector.

Abstract: Fuel control dynamic health assessment systems and methods related to monitoring fuel flow control are provided. In one embodiment, a method for controlling a system having an engine, includes determining a predicted valve position of a valve, the valve being operable to control fuel flow to a fuel pump that pumps fuel to a common fuel rail of the engine, determining an actual valve position, determining an error between the predicted valve position and the actual valve position, and setting a degradation condition in response to the error.

Abstract: An engine system includes an exhaust system fluidly connected to an electronically controlled engine. Exhaust from the engine may travel a first pathway through a turbine of a turbocharger, or a second pathway that bypasses the turbine. An electronically controlled wastegate vale is biased to close the second pathway. An electronic controller is in communication with the electronically controlled engine and the electronically controlled wastegate valve. The electronic controller is configured to execute a wastegate diagnostic algorithm to detect a stuck closed default condition of the electronically controlled wastegate valve, and derate the engine in response to detection of a stuck closed fault condition.

Abstract: In a common rail system having two electrically controlled actuating elements, e.g., a metering unit at the input side of a high-pressure pump and a pressure regulating valve on the common rail, different fuel delivery quantities are able to be set in the common rail system while the vehicle is stationary, independent of the current engine load, by controlling operating points via one of the actuating elements and subsequently regulating the other actuating element. Control currents of the actuating elements correspond to the operating points. These control currents, or differences of control currents, are compared to target values to enable an evaluation of the common rail system.

Abstract: The present invention provides a control apparatus used in an internal combustion engine that can switchably use a compressed natural gas and gasoline. The control apparatus carries out a miss fire check on the internal combustion engine over two or more combustion cycles, and, based on the results of the check, detects failures. The control apparatus prohibits switching of fuels (S23, S24, S28) basically during the miss fire check. If the value of a miss fire counter is not increasing, the control apparatus predicts that a negative check result will not be obtained (S26), and lifts the prohibition on switching of fuels (S29).

Abstract: Example embodiments disclose a drive system including a machine including a plurality of phases and configured to generate power based on a plurality of phase currents, each respectively associated with the plurality of phases and a direct current (DC) bus, operatively connected to the machine. The DC bus includes a high-side line, a low-side line, and an inverter including a plurality of switching systems, operatively connected between the high-side line and the low-side line, the plurality of switching systems, each configured to output a respective one of the plurality of phase currents. The drive system also includes a controller, operatively connected to the DC bus and the machine, the controller configured to determine if a failure exists in the drive system based on the plurality of phase currents and a DC bus voltage, the DC bus voltage being a voltage across the high-side line and the low-side line.

Abstract: An apparatus for detecting an abnormal air-fuel ratio variation, includes an abnormality detecting unit that detects an abnormal variation in each of a plurality of fuel injection valves on the basis of an injection ratio between the plurality of fuel injection valves, a fluctuation in the output before the injection ratio is changed and the fluctuation in the output after the injection ratio is changed; and a setting unit that corrects the abnormality determination threshold for each of the plurality of fuel injection valves on the basis of the injection ratio.

Abstract: A device and a method are provided for diagnosing a technical apparatus which is particularly developed as an internal combustion engine. When specified states of the technical apparatus are present, the means of diagnosis are activated, and when at least one of the specified technical states is no longer present, the means of diagnosis are deactivated. Upon the deactivation, information is stored that identifies which technical state is no longer present.

Abstract: An object of the present invention is to suppress the dispersion of EGR gas amount between cylinders when the stuck open state arises in an EGR valve in an EGR apparatus for an internal combustion engine in which an EGR passage is branched on an intake system side into a plurality of EGR branch pipes, and the respective EGR branch pipes are connected respectively to intake branch pipes provided for the respective cylinders. In the present invention, if the EGR valve is stuck open, the exhaust pressure is reduced in an exhaust system of the internal combustion engine, while suppressing an amount of decrease in a driving force of a vehicle which carries the internal combustion engine within an allowable range.

Abstract: A combustion engine has a fuel supply unit, an ignition unit and a controller controlling the amount of fuel and the ignition time. An adjustable throttle element controlling the amount of combustion air to the engine and an adjustable idling stop for the throttle element are provided. The controller includes a regulating unit regulating the rotational speed of the motor to a set-point rotational speed (nsoll) when idling. To adjust the idling stop, the regulating unit is switched off when idling. A diagnostic unit switches off the regulating unit. A method for adjusting a combustion engines provides that the regulating unit is switched off, the amount of fuel supplied is adjusted during idling and a rotational speed is evaluated, and that on the basis of the rotational speed value, it is determined how the idling stop is to be adjusted to reach a set-point rotational speed maximum (nsollmax).

Abstract: A drive circuit (52) that is commonly provided with respect to two fuel injection valves (24R and 24L) for the same cylinder, and drive the two fuel injection valves (24R and 24L) for the same cylinder on the basis of a command from an ECU (40), is provided. An electric conduction line (52) that electric current supplied to the two fuel injection valves (24R and 24L) flows through, is provided. The electric conduction line (52) includes a common section (56a) one end of which is connected to the drive circuit (52), and branch sections (56b) which are sections following the other end of the common section (56a) that the electric conduction line (56) branches off at and on which the two fuel injection valves (24R and 24L) for the same cylinder are respectively installed. The electric current value I flowing through the common section (56a) is detected. An electric resistance (58) that is inserted in the branch section (56b) for the fuel injection valve (24L), is provided.

Abstract: In order to locate errors of the rail pressure sensor (38) when starting problems occur, the following method steps are proposed: determination of whether starting problems occur in the engine and if this is the case, an engine state is induced, in which the engine controller is already active but the starting phase of the engine has not yet commenced; substitution of the measured rail pressure sensor value used by the engine controller with a substitute value; start attempt of the engine and determination whether the engine has achieved an independent operation; and identification of an error function of the rail pressure sensor if the starting problems only occur when the measured rail pressure sensor value is used.

Abstract: A control device for a multi-cylinder internal combustion engine executes feedback control such that an air-fuel ratio detected by an air-fuel ratio detecting unit becomes a target air-fuel ratio, carries out external EGR, and, when an abnormal deviation that an air-fuel ratio of at least any one of cylinders deviates from the target air-fuel ratio has occurred during the feedback control, detects the abnormal deviation and an abnormal cylinder. When the abnormal deviation has been detected during feedback control and external EGR, the control device corrects the target air-fuel ratio to compensate for a detection error of the air-fuel ratio detecting unit due to the influence of specific components of exhaust gas. The control device changes the correction mode on the basis of whether the abnormal cylinder causes more intensive gas flow or equal or less intensive gas flow against the air-fuel ratio detecting unit than the other cylinders.