Abstract: An air-fuel ratio estimating device can include an amount of fuel injected calculating unit which can estimate the amount of fuel injected GF for each cycle on the basis of a driving time Tout of a fuel injection valve. A proportional constant calculating section determines a proportional constant K, using the estimated charging efficiency CE and the amount of fuel injected Gf, when the output value of a sensor is in a transition region R. When the sensor output value is not in the transition region R, an air-fuel ratio A/F is estimated from the determined proportional constant K, a charging efficiency CE calculated by a calculating section, and the amount of fuel injected Gf.

Abstract: A procedure and device for diagnosing the increasing speed and the dead time of an exhaust gas probe includes carrying out the diagnosis by comparing a modeled and a measured signal after a default change of a fuel air ratio of an air fuel mixture that is supplied to a combustion engine. The signal is an output signal of the exhaust gas probe or a modeled or measured signal that is derived from the output signal. The device for diagnosing the velocity and the dead time of an exhaust gas probe also includes a comparing unit for comparing the modeled signal with the measured signal for diagnosing the velocity and the dead time of the exhaust gas probe after a default change of a fuel air ratio of an air fuel mixture that is supplied to the combustion engine.

Abstract: An abnormality determination device for an air-fuel ratio sensor includes a differential value calculator and an abnormality determiner. The differential value calculator is configured to calculate a differential value of an output value of the air-fuel ratio sensor which is configured to detect an air-fuel ratio of exhaust gas. The abnormality determiner is configured to determine abnormality of the air-fuel ratio sensor based on a result of comparison between a reference output value of the air-fuel ratio sensor and a predetermined threshold. The reference output value is obtained by the air-fuel ratio sensor when the differential value calculated by the differential value calculator becomes a predetermined value.

Abstract: An air-fuel ratio imbalance among cylinders determining apparatus according to the present invention is applied to a multi-cylinder internal combustion engine in which a compression ratio is variable. The determining apparatus obtains, using at least an output value of an upstream air-fuel ratio sensor disposed for a catalyst, an “imbalance determining parameter” which becomes larger as a degree of an imbalance among “individual cylinder air-fuel ratios” becomes larger, each of the individual cylinder air-fuel ratios being an air-fuel ratio of a mixture supplied to each of cylinders. Further, the determining apparatus determines that an air-fuel ratio imbalance state among cylinders is occurring, when the imbalance determining parameter is larger than a predetermined threshold. The determining apparatus changes the predetermined threshold in accordance with a mechanical compression ratio of the engine.

Abstract: In a method and system to diagnose exhaust gas sensor deterioration, an automobile includes an exhaust gas system. The exhaust gas system has a fuel delivery system, an engine, a catalytic converter, an exhaust gas sensor, a processor, and/or a memory. The fuel delivery system supplies fuel which is combined with air to form a mixture combusted by the engine to generate exhaust. The processor controls the air-fuel ratio of the mixture based on the air-fuel ratio data of the exhaust detected by the exhaust gas sensor. The catalytic converter reduces pollutants in the exhaust. The processor analyzes the air-fuel ratio data to determine one or more time constants of a step response for rich to lean fuel operations and/or lean to rich fuel operations. The processor compares the time constants to a predetermined time constant threshold to determine if the exhaust gas sensor has malfunctioned.

Abstract: The present invention provides, as one aspect, a signal processor for a gas sensor that is disposed in an exhaust passage of an internal combustion engine and senses concentration of a specific component in exhaust gas. The signal processor includes a calculation unit that performs moderation operation at every instant for a sensor output of the gas sensor, an evaluation unit that evaluates a degree of pressure variation impact on the sensor output caused in the exhaust passage, and a change unit that changes a mode of the moderation operation according to a result of the evaluation by the evaluation unit.

Abstract: An abnormality detection device for an internal combustion engine capable of performing abnormality detection with accuracy, and an air/fuel ratio control apparatus for an internal combustion engine capable of performing air/fuel ratio control with accuracy. An estimated value of the amount of intake air at a valve closing time at which an intake value is closed, is computed. The in-cylinder air/fuel ratio in a cylinder is computed by using the estimated value. The obtained in-cylinder air/fuel ratio is used as an input air/fuel ratio to identify a parameter in a primary delay element. Determination as to the existence/nonexistence of an abnormality in a pre-catalyst sensor (A/F sensor) is made on the basis of the obtained parameter.

Abstract: An apparatus or a method for detecting an abnormality of inter-cylinder air-fuel ratio dispersion in a multi-cylinder internal combustion engine according to the invention is equipped with a catalytic element that purifies exhaust gas of hydrogen, a first air-fuel ratio sensor that detects an air-fuel ratio of exhaust gas that has not passed through the catalytic element, a second air-fuel ratio sensor that detects an air-fuel ratio of exhaust gas that has passed through the catalytic element, a device that detects an abnormality of inter-cylinder air-fuel ratio dispersion on the basis of a divergence state of a detected value of a second air-fuel ratio to a lean side from a detected value of a first air-fuel ratio, and a device that forcibly reduces fuel injection amounts in cylinders individually when an abnormality on dispersion is detected by the abnormality detector, detects a divergence state of the detected value of the second air-fuel ratio to the lean side from the detected value of the first air-fue

Abstract: A plateau phase of a test signal of an exhaust gas probe located in a catalytic converter is detected following a jump from a preset rich air/fuel ratio in a combustion chamber of one cylinder to a preset lean air/fuel ratio, the plateau phase being obtained following the jump, and the duration is determined as a storage period. A plateau phase of the test signal, which is obtained following a jump from a preset lean air/fuel ratio to a preset rich air/fuel ratio, is detected following the jump, and the duration of the plateau phase is determined as an evacuation period. An allocation rule for assigning the test signal to a detected air/fuel ratio is adjusted according to the storage period and the evacuation period. To calibrate the exhaust gas probe, the allocation rule is adapted according to a plateau value of the test signal during the plateau phase.

Abstract: When a wastegate valve, which opens and closes an exhaust bypass passage bypassing an exhaust turbine, is open, exhaust gases of respective cylinders bypass the exhaust turbine and pass a sensing point of an air-fuel ratio sensor downstream of the exhaust turbine. Accordingly, the exhaust gases of the respective cylinders can be avoided from being mixed by the exhaust turbine, so an influence of an inter-cylinder variation in an air-fuel ratio due to an inter-cylinder imbalance abnormality becomes apt to appear in an output waveform of the air-fuel ratio sensor. Therefore, existence or nonexistence of the inter-cylinder imbalance abnormality is determined based on the output of the air-fuel ratio sensor when the wastegate valve is open. Eventually, the existence or nonexistence of the inter-cylinder imbalance abnormality can be determined accurately, thereby improving detection accuracy of the inter-cylinder imbalance abnormality.

Abstract: Provided is a control device for an internal combustion engine that can execute a sulfur purge in a favorable manner under all conditions without complicating the control action or the engine structure. The process comprises detecting a temperature of the NOx catalytic converter, detecting an exhaust air fuel ratio in the catalytic converter, computing a target exhaust air fuel ratio according to a detected temperature of the NOx catalytic converter, and controlling a fuel injection valve so as to make an actual exhaust fuel ratio agree with the target exhaust air fuel ratio. If the temperature of the NOx catalytic converter is not high enough to enable a sulfur purge, a temperature increase control is executed to increase the temperature of the NOx catalytic converter by suitably changing various engine parameters.

Abstract: This disclosure provides a method of detecting a cylinder-to-cylinder gap abnormality of an air fuel ratio with sufficient accuracy according to an individual specificity of an air fuel ratio detecting module. Particularly, the method may be used for an engine to detect the cylinder-to-cylinder gap abnormality of the air fuel ratio of supplied air fuel mixture abnormality based on an output value of a linear O2 sensor. Under a first predetermined condition, an output characteristic of the sensor is measured. The measured output characteristic is compared with a reference characteristic set in advance to calculate a correction value for correcting the sensor output according to the individual specificity of the sensor. Subsequently, under a second predetermined condition, the sensor output value is corrected based on the calculated correction value to detect the abnormality based on the corrected output value of the sensor.

Abstract: This disclosure provides a method for measuring an output characteristic of an air fuel ratio sensor based on an output value of the air fuel ratio sensor at the time of changing a fuel injection amount. Under a predetermined condition, an increase in the fuel injection amount is started from a particular cylinder and the increase in the fuel injection amount is continued for a given time period, or a decrease in the fuel injection amount is started from the particular cylinder and the decrease in the fuel injection amount is continued for the given time period. Therefore, the output characteristic of the air fuel ratio detecting module can be measured with sufficient accuracy, regardless of the contacting strength of emission gas for every cylinder against the air fuel ratio detecting module.

Abstract: A device and a method for controlling an internal combustion engine, in which an actual value is determined based on a lambda value and compared with a setpoint value. Based on the comparison, a correction value for a controlled variable is determined and stored. An error is detected if the correction value changes abruptly.

Abstract: In a method for determining a correction value ?k for the lambda center position ?m which is specified in the control of the air/fuel ratio which is force-modulated between a first lean lambda value ?1 and a second rich lambda value ?2 and supplied to an internal combustion engine or a catalyst, using the signal from a binary jump sensor downstream from a catalyst volume, and whenever the jump sensor signal U? jumps from “lean” to “rich” or from “rich” to “lean” the air/fuel ratio is switched back and forth between the lean lambda value ?1 and the rich lambda value ?2, it is proposed that the time period between two signal jumps U?, which indicates the residence time T1 in the lean phase or the residence time T2 in the rich phase, is determined, and the correction value ?k is determined from the first lean lambda value ?1, the second rich lambda value ?2, the first residence time T1, and the second residence time T2.

Abstract: Depending on a trim controller diagnosis, a suspicion marker for an asymmetric ageing of the exhaust gas probe is allocated either a “true” value or a “false” value and, if the value of the suspicion marker is “true”, a dynamic diagnosis will be performed based on the exhaust gas probe's measuring signal, on the basis of the results of which diagnosis either an asymmetrically aged or a non-asymmetrically aged exhaust gas probe will be detected.

Abstract: A method of monitoring a performance of an oxygen sensor is disclosed. One embodiment comprises determining a first air/fuel ratio from a signal from an exhaust oxygen sensor; determining a second air/fuel ratio from a temperature upstream of the particulate filter, a pressure differential across the particulate filter and one or more of an airflow into the engine and a fuel flow into the engine; comparing the first air/fuel ratio and the second air/fuel ratio; and diagnosing an error condition of the oxygen sensor if the first air/fuel ratio does not meet a predetermined condition relative to the second air/fuel ratio.

Abstract: The invention relates to a method for regulating the lambda value of an internal combustion engine with a catalytic converter for subsequently treating the exhaust gases of the internal combustion engine, with a binary lambda probe, which is mounted upstream from the catalytic converter and which senses the composition of the exhaust gases. According to the invention, the lambda set value is superimposed with a lean/rich amplitude. This lean/rich amplitude has an integral component and a discontinuous component leading back to the lambda set value. When a change that differs from the change in the exhaust gas composition caused by the lean/rich amplitude is detected, the coefficient of the integral component is modified and/or a discontinuous component is added to the integral component or subtracted therefrom.

Abstract: A vehicle-mounted engine control apparatus can accurately measure the resistance value of a label resistor arranged in an exhaust gas sensor for correcting characteristic variation thereof by using a reduced number of wires. An electric heater of the exhaust gas sensor, which is powered from a second power supply wire, as well as the label resistor and air fuel ratio measurement elements are connected to the apparatus which is powered from an on-vehicle battery through a first power supply wire. A power feed voltage of the apparatus is input to a multichannel AD converter through voltage dividing resistors, so that a positive end potential of the label resistor is measured alternatively. A negative end potential of the label resistor is input to the converter as a divided voltage thereof with a fixed resistor. The label resistance value is calculated from a fixed resistor current and a label resistor voltage.

Abstract: A deterioration diagnosis system for an air fuel sensor mounted to an exhaust pipe of an internal combustion engine. The air fuel sensor determines a mixture ratio of air and fuel fed into the internal combustion engine. In the system, an inclination of an output signal of the air-fuel ratio sensor is calculated; variance of the inclination is calculated; deterioration of the air-fuel ratio sensor is determined based on the variance of the inclination.

Abstract: An abnormality diagnosis apparatus for an internal combustion engine includes an abnormality diagnosis unit, an other fuel contamination determination unit, and a misdiagnosis prohibition unit. The abnormality diagnosis unit determines whether there is an abnormality in a fuel system based on an output from an exhaust gas sensor mounted on an exhaust duct of the internal combustion engine. The other fuel contamination determination unit determines whether an other fuel contaminates a supply fuel supplied to the internal combustion engine. The misdiagnosis prohibition unit conducts one of (a) changing an abnormality determination condition for the abnormality diagnosis in the fuel system and (b) prohibiting the abnormality diagnosis in the fuel system, when the other fuel contamination determination unit determines that the other fuel contaminates the supply fuel.

Abstract: A method for determining degradation of an exhaust gas sensor positioned in an exhaust system for an internal combustion engine of a vehicle is provided. The method includes modulating an air/fuel ratio of gas exhausted by the internal combustion engine to the exhaust system through a cycle that includes at least one rich-to-lean transition and at least one lean-to-rich transition, indicating a degradation condition of the exhaust gas sensor in response to at least one of a rich-to-lean response duration of the exhaust gas sensor and a lean-to-rich response duration of the exhaust gas sensor being greater than a delay threshold, and indicating the degradation condition of the exhaust gas sensor in response to a ratio of the rich-to-lean response duration to the lean-to-rich response duration being greater than an asymmetry threshold that is relative to an axis of symmetry of the rich-to-lean response duration versus the lean-to-rich response duration.

Abstract: To avoid potentially erroneous results, monitoring the operation of an oxygen sensor of an internal combustion engine of a motor vehicle to detect a slow response of the oxygen sensor as indicative of an oxygen sensor fault is temporarily suspended in response to a brake operation transition of a braking system of the vehicle.

Abstract: An abnormality diagnosis apparatus for diagnosing abnormality of a secondary air supply assembly includes an abnormality diagnosing unit, an air-fuel ratio learning/correcting unit, a learning degree computing unit, and a prohibition unit. The abnormality diagnosing unit diagnoses abnormality of the secondary air supply assembly based on an output of the air-fuel ratio detecting unit. The air-fuel ratio learning/correcting unit learns variation of an air-fuel ratio control system of the engine and corrects variation of an air-fuel ratio based on a result of learning the variation of the air-fuel ratio control system. The learning degree computing unit computes a learning degree, by which the air-fuel ratio learning/correcting unit learns the variation of the air-fuel ratio control system. The prohibition unit prohibits the abnormality diagnosis or makes a diagnostic result invalid when the learning degree is equal to or less than a predetermined value.

Abstract: An abnormality diagnosis device according to the present invention can calculate a calculation air-fuel ratio A/Fk based upon a fuel injection quantity and an intake air quantity, and determine the abnormality of the air-fuel ratio sensor based upon the calculation air-fuel ratio and an actual air-fuel ratio detected by an air-fuel ratio sensor, when an operating condition in the internal combustion engine relatively rapidly changes according to an engine operating demand and thereby the calculation air-fuel ratio relatively rapidly changes. Since the air-fuel ratio is not forcibly changed and fluctuated, deterioration of the exhaust emission and the combustion state, and deterioration of the vibration and the noise at abnormality diagnosing can be certainly prevented.

Abstract: A Calibrated Air Intake Tract for Internal Combustion Engine is disclosed. The intake includes a Mass Airflow Sensor section that defines an inner diameter that differs from the diameter of the overall intake air tract piping. The Mass Airflow Sensor length and diameter are precision-tuned in order to provide the best engine performance without the typical “check engine” light being lit due to faulty mass airflow sensor readings. In those vehicles where necessary, an insert of the appropriate size and in the proper location is added to the interior wall of the MAFS section in order to correct final fuel trim level inadequacies.

Abstract: The present Invention is directed to an electronic system that allows for a lower consumption of fuel and emission of polluting gases that are generated after the air/fuel mixture is burned by the internal combustion engine.

Abstract: An air/fuel imbalance detection module includes a fueling control module, a response time determination module, and a comparison module. The fueling control module commands a fueling change according to a predetermined fueling pattern. The response time determination module determines a measured response time for a wide-range air/fuel sensor (WRAF) to output a predetermined voltage. The comparison module compares the measured response time with a reference time range and diagnoses air/fuel imbalance when the measured response time is outside the reference time range.

Abstract: An abnormality detection device for an internal combustion engine capable of performing abnormality detection with accuracy, and an air/fuel ratio control apparatus for an internal combustion engine capable of performing air/fuel ratio control with accuracy. An estimated value of the amount of intake air at a valve closing time at which an intake value is closed, is computed. The in-cylinder air/fuel ratio in a cylinder is computed by using the estimated value. The obtained in-cylinder air/fuel ratio is used as an input air/fuel ratio to identify a parameter in a primary delay element. Determination as to the existence/nonexistence of an abnormality in a pre-catalyst sensor (A/F sensor) is made on the basis of the obtained parameter.

Abstract: A method for determining a deviation of a fuel quality from a reference quality and for determining a change in exhaust gas emissions caused by this deviation by evaluating pressure waves in a fuel system of an internal combustion engine outfitted with one of a discontinuous fuel delivery and a fuel take-off.

Abstract: An internal combustion engine has at least one cylinder and an exhaust gas tract, in which an exhaust gas sensor, that can be heated in a controlled manner, is arranged. An exhaust gas temperature of an exhaust gas flowing in the exhaust gas tract is determined as a function of the heating power (P_HEAT) supplied to the exhaust gas sensor. An estimated value of the exhaust gas temperature is determined as a function of a physical model of the combustion of the air/fuel mixture and of the exhaust gas tract as a function of at least one operating variable of the internal combustion engine, but independent of the heating power supplied to the exhaust gas sensor. Model parameters of the physical model are adapted as a function of a deviation of the estimated value and of the exhaust gas temperature determined by the supplied heating power.

Abstract: A cylinder deviation of an actual air-fuel ratio before an air-fuel-ratio dither control is obtained based on a variation of an actual air-fuel ratio by the dither control, a variation amount of detected air-fuel ratio, and a cylinder deviation of detected air-fuel ratio before the dither control. A cylinder deviation of actual air-fuel ratio of each cylinder is accurately estimated. When the number of times in which the cylinder deviation of air-fuel ratio exceeds a decision value is greater than a predetermined number, it is determined that an abnormality occurs in the cylinder.

Abstract: The engine misfire detection process according to one aspect of the invention first makes tentative detection on the occurrence or the non-occurrence of an engine misfire in execution of both vibration control and rotation speed control. In response to the tentative detection of an engine misfire, the engine misfire detection process subsequently makes final detection on the occurrence or the non-occurrence of an engine misfire. In the event of no final detection of an engine misfire, the engine misfire detection process makes tentative detection and final detection on the occurrence or the non-occurrence of an engine misfire in prohibition of the vibration control. In the event of still no final detection of an engine misfire, the engine misfire detection process makes tentative detection and final detection on the occurrence or the non-occurrence of an engine misfire in further prohibition of the rotation speed control.

Abstract: It is an object of the present invention to provide a gas concentration detection apparatus that is capable of forming an accurate activity judgment when a gas concentration detection cell begins to detect gas concentration with high accuracy. When warm-up begins at time t0 in a NOx concentration detection apparatus that achieves NOx concentration detection with a NOx sensor cell after excess oxygen is discharged by an oxygen pump cell, a NOx sensor cell output begins to rise at time t1. Subsequently, at time t2, an oxygen pump cell output begins to rise. An inflection point appearing in the NOx sensor cell output is then located. At time t5 at which the inflection point appears, an activity judgment about the NOx sensor cell is formed.

Abstract: The invention relates to a procedure and a device for diagnosing the increasing speed and the dead time of an exhaust gas probe, which is arranged in the exhaust gas duct of a combustion engine, whereby the diagnosis is carried out due to a comparison of a modeled and a measured signal after a default change of a fuel air ratio of an air fuel mixture that is supplied to the combustion engine and whereby the signal is an output signal of the exhaust gas probe or a modeled or measured signal that is derived from the output signal.

Abstract: An air/fuel imbalance (AFIM) diagnostic system comprises a first module, an imbalance determination module, and an imbalance diagnostic module. The first module outputs imbalance data samples based on an oxygen signal provided by an oxygen sensor measuring oxygen in exhaust expelled from cylinders of a cylinder bank. The imbalance determination module determines an AFIM value based on the imbalance data samples. The imbalance diagnostic module selectively diagnoses an AFIM in the cylinder bank based on the AFIM value.

Abstract: In relation to a jump (SP_J_LR) from a lean air-to-fuel ratio to a richer air-to-fuel ratio, a measurement signal of the exhaust gas probe is detected after a predetermined lean-to-rich delay (t_R) as a lean-to-rich signal value (SV_LR) and is placed in relation to a lean-to-reference signal value (L_REF). In relation to a jump (SP_J_RL) from a richer air-to-fuel ratio to a leaner air-to-fuel ratio, the procedure is performed equivalently. Depending on the lean-to-rich and lean-to-rich signal value put in relation, either an asymmetrically aged or non-asymmetrically aged exhaust gas probe is detected.

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: By a respective cylinder-specific lambda regulator, a regulator value for influencing the air/fuel ratio in the respective cylinder is determined as a function of the cylinder-specific air/fuel ratio measured for the respective cylinder. The regulator value is monitored for the attainment of a first predefined threshold value, and when the latter is reached, a lambda quality value is determined which is representative of the deviation of the measured cylinder-specific air/fuel ratios assigned to the respective cylinders. The regulator value is monitored for the attainment of a second predefined threshold value which is representative of a more pronounced regulating intervention than the first threshold value. When the second predefined threshold value is reached, the lambda quality value is determined. If the lambda quality value assigned to the first threshold value is lower than the value assigned to the second threshold value, unstable regulating behaviour is identified.

Abstract: A gas sensor diagnostic method includes the steps of counting the reversal number of times that a target air-fuel ratio for an air-fuel mixture to be supplied to an internal combustion engine reverses from a rich side to a lean side or from the lean side to the rich side through a specific air-fuel ratio defined as a boundary of the rich and lean sides; obtaining a detection signal of gas sensor at constant time intervals during a diagnosis period between a timing when the count for the reversal number is started and a timing when the reversal number reaches a predetermined number; calculating a first moderated signal by applying a first moderation calculation to the detection signal, and a second moderated signal by applying a second moderation calculation to the detection signal; calculating a deviation between the first and second moderated signals; and determining whether the gas sensor is in the abnormal state on the basis of the deviation obtained during the diagnosis period.

Abstract: An apparatus or a method for detecting an abnormality of inter-cylinder air-fuel ratio dispersion in a multi-cylinder internal combustion engine according to the invention is equipped with a catalytic element that purifies exhaust gas of hydrogen, a first air-fuel ratio sensor that detects an air-fuel ratio of exhaust gas that has not passed through the catalytic element, a second air-fuel ratio sensor that detects an air-fuel ratio of exhaust gas that has passed through the catalytic element, a device that detects an abnormality of inter-cylinder air-fuel ratio dispersion on the basis of a divergence state of a detected value of a second air-fuel ratio to a lean side from a detected value of a first air-fuel ratio, and a device that forcibly reduces fuel injection amounts in cylinders individually when an abnormality on dispersion is detected by the abnormality detector, detects a divergence state of the detected value of the second air-fuel ratio to the lean side from the detected value of the first air-fue

Abstract: In a method and a control apparatus for monitoring an exhaust gas probe, the exhaust gas probe is arranged in an exhaust gas channel. The exhaust gas channel is connected to an internal combustion engine, with the internal combustion engine being supplied with a rich or lean air/fuel ratio in an oscillating fashion. An amplitude of a signal based on the oscillating output signal of the exhaust gas probe is determined and used to evaluate the exhaust gas probe.

Abstract: An air-fuel ratio of each cylinder is estimated on the basis of the detection value of an air-fuel ratio sensor disposed in an exhaust confluent portion. An air-fuel ratio correction quantity is computed on the basis of the estimated air-fuel ratio of each cylinder and the air-fuel ratio correction quantity is learned by smoothing processing. The air-fuel ratio is corrected on the basis of the cylinder air-fuel ratio correction quantity, whereby the air-fuel ratio is controlled for each cylinder so as to reduce a variation in the air-fuel ratio between the cylinders. When a state in which the correction quantity of any cylinder is outside a specified range continues for a while during a period in which the air-fuel ratio is controlled for each cylinder, the correction quantity is prohibited from being learned, whereby the cylinder air-fuel ratio correction quantity is prevented from being erroneously learned.

Abstract: A method for sensing an air-fuel ratio of exhaust gasses from an engine of a vehicle using a sensor, the sensor having a pumping cell and a reference cell, the method comprising pumping a current in the pumping cell during at least a first set of operating conditions; reducing said pumping during at least a second set of operating conditions; providing a signal from the sensor during at least the first and second sets of operating conditions; and adjusting at least one of a fuel injection amount and an air amount into the engine to maintain a desired air-fuel ratio based on the signal during at least the first and second sets of operating conditions.

Abstract: A gas sensor diagnostic method includes the steps of counting the reversal number of times that a target air-fuel ratio for an air-fuel mixture to be supplied to an internal combustion engine reverses from a rich side to a lean side or from the lean side to the rich side through a specific air-fuel ratio defined as a boundary of the rich and lean sides; obtaining a detection signal of gas sensor at constant time intervals during a diagnosis period between a timing when the count for the reversal number is started and a timing when the reversal number reaches a predetermined number; calculating a first moderated signal by applying a first moderation calculation to the detection signal, and a second moderated signal by applying a second moderation calculation to the detection signal; calculating a deviation between the first and second moderated signals; and determining whether the gas sensor is in the abnormal state on the basis of the deviation obtained during the diagnosis period.

Abstract: A deterioration signal generation device for a gas sensor for simulating a deterioration signal output by a gas sensor in a deteriorated state, the gas sensor detecting the fuel-air ratio of exhaust gas from an internal combustion engine based on the concentration of particular components in the exhaust gas, the deterioration signal generation device including a reference signal acquisition unit as defined herein, a reference signal storing unit as defined herein, a delay time setting unit as defined herein and a signal delay generation unit as defined herein.

Abstract: The invention relates to a method for determining the actual oxygen load of a 3-path catalyst of a lambda-controlled internal combustion engine, whereby a value for the actual oxygen load is calculated from the signal of a pre-catalyst lambda probe and the measured air mass flow rate by integration over time, whereby the post-catalyst lambda probe is initialized when the signal is interrupted.

Abstract: A plateau phase of a test signal of an exhaust gas probe located in a catalytic converter is detected following a jump from a preset rich air/fuel ratio in a combustion chamber of one cylinder to a preset lean air/fuel ratio, the plateau phase being obtained following the jump, and the duration is determined as a storage period. A plateau phase of the test signal, which is obtained following a jump from a preset lean air/fuel ratio to a preset rich air/fuel ratio, is detected following the jump, and the duration of the plateau phase is determined as an evacuation period. An allocation rule for assigning the test signal to a detected air/fuel ratio is adjusted according to the storage period and the evacuation period. To calibrate the exhaust gas probe, the allocation rule is adapted according to a plateau value of the test signal during the plateau phase.

Abstract: The invention provides an engine controller, which can determine a deterioration mode (gain deterioration or response deterioration) of an air/fuel (A/F) ratio sensor, can detect a degree of the deterioration with high accuracy, and can optimize A/F ratio feedback control in accordance with the diagnosis result. The controller includes a unit for computing frequency response characteristics in a range from an A/F ratio adjusting unit to the A/F ratio sensor, and it diagnoses the A/F ratio sensor based on a gain characteristic and a response characteristic given by the computed frequency response characteristics. In accordance with the diagnosis result, parameters (P- and I-component gains) used in A/F ratio feedback control (PI control) are optimized.

Abstract: Disclosed is an internal combustion engine comprising at least one cylinder and an exhaust manifold in which a catalytic converter, a first exhaust gas probe, and a second exhaust gas probe are disposed. The first exhaust probe is located upstream from the catalytic converter while the second exhaust gas probe is arranged downstream therefrom. A lambda Controller is provided which is configured so as to determine a lambda correction factor in accordance with a first test signal that is assigned to the first exhaust gas probe. A trim controller is provided to which a setpoint value and an actual value of a second test signal allocated to the second exhaust gas probe are fed as a control difference. The trim controller is configured so as to determine a proportionate corrective factor.