Abstract: A control device is arranged to control an oxygen sensor for an automotive vehicle wherein the oxygen sensor has a sensor element and a heater for elevating a temperature of the sensor element. The control device includes a tilt detection section arranged to detect tilting of a vehicle body; a storage section arranged to store tilt information in accordance with a result of detection by the tilt detection section; and a control section arranged to control, at a start of an engine of the vehicle, the heater in one of a plurality of modes including a normal mode and a delay mode in which temperature elevation of the sensor element is delayed relative to the normal mode, based on the tilt information stored in the storage section.

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 EG-ECU suspends fuel cutoff when the fuel cutoff is being carried out and the engine speed NE becomes lower than or equal to the resumption engine speed NErtn. The EG-ECU forcibly opens and closes an EGR valve when the fuel cutoff is being carried out, and performs abnormality diagnosis for an EGR device based on a change amount of pressure in an intake pipe caused by opening and closing the EGR valve. The EG-ECU suspends the diagnosis when the diagnosis is being carried out and the engine speed NE becomes lower than or equal to a forcible suspension engine speed NEoff. When the diagnosis is being performed, the EG-ECU sets the forcible suspension engine speed NEoff to a smaller value when the EGR valve is not in a forcibly opened state than when the EGR valve is in the forcibly opened state.

Abstract: An apparatus and a method for detecting abnormal air-fuel ratio variation among cylinders of a multi-cylinder internal combustion engine are provided. The apparatus includes: a catalyst that is provided in an exhaust passage of the multi-cylinder internal combustion engine; a catalyst temperature detection unit that detects a temperature of the catalyst; a catalyst temperature estimation unit that estimates a temperature of the catalyst based on an engine operating state; and an abnormality detection unit that determines whether abnormal air-fuel ratio variation among the cylinders has occurred based on the detected temperature of the catalyst and the estimated temperature of the catalyst.

Abstract: For operating a internal combustion engine a first characteristic value is determined depending on a distance integral of at least a portion of a control signal of an oxygen sensor control based on control reference signal characteristics across a given time period. Depending on the first characteristic value (KW—1) a quality value (GW—1) is determined. Depending on the quality value (GW1) either the existence or the non existence of an error of the exhaust sensor is detected.

Abstract: A other-type fuel contamination determination apparatus for an internal combustion engine includes an exhaust gas sensor. The exhaust gas sensor is configured for obtaining one of (a) an air-fuel ratio and (b) a combustion state for the internal combustion engine based on exhaust gas. The other-type fuel contamination determination apparatus determines whether other-type fuel contaminates fuel that is supplied to the internal combustion engine based on an output by the exhaust gas sensor.

Abstract: An engine controller for a vehicle equipped with an emission reduction apparatus determines whether the emission reduction apparatus has malfunction. When it is determined that the emission reduction apparatus has malfunction an execution of an idle shutdown control process is permitted. When a predetermined condition is established during an engine idling, the engine is automatically shut down. On the other hand, when it is determined that the emission reduction apparatus has no malfunction, the execution of the idle shutdown control process is prohibited.

Abstract: A pressure sensor is located in a fuel passage, which extends from a pressure-accumulation vessel to a nozzle hole of a fuel injection valve. The pressure sensor is located closer to a nozzle hole than the pressure-accumulation vessel for detecting pressure fluctuated by injection of fuel through the nozzle hole. An instruction signal output unit outputs an injection instruction signal so as to instruct an injection mode of fuel to the fuel injection valve. A defective injection determination unit determines whether a detected pressure of the fuel pressure sensor is fluctuated in a fluctuation mode in a range assumed from the injection instruction signal. The defective injection determination unit determines that a defective injection occurs when determining that the detected pressure is out of the fluctuation mode in the assumed range.

Abstract: An internal combustion engine includes an exhaust system, an oxygen sensor in the exhaust system and a sensor malfunction monitor. The sensor malfunction monitor measures a rate of change of a signal from the sensor on detecting a turning point of the signal and detects a malfunction when a rate of change of the signal exceeds a threshold. Alternatively, the sensor malfunction monitor measures a response time interval starting from a point in time at which a diagnostic function begins to force an air-fuel ratio to change (e.g., from lean-to-rich or rich-to-lean) and ends at a point in time when a turning point of the signal is detected. The sensor malfunction monitor detects a malfunction when the delay time of the response time interval, or average delay time from a plurality of measured response time intervals, exceeds a time threshold.

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: An abnormality detection apparatus includes: an air/fuel ratio control portion that performs a control of fluctuating the air/fuel ratio; a data acquisition portion that acquires, as data for detecting abnormality, a responsiveness parameter while output of the air/fuel ratio sensor changes between rich and lean peaks during the control; an abnormality determination portion that determines presence/absence of abnormality of the sensor by using the data; and a distribution width determination portion that finds a distribution width of the data acquired by performing a plurality of acquisitions of the data, in an increase/decrease direction of the data. On the basis of comparison between the distribution width and an abnormality criterion value, the abnormality determination portion determines that the sensor has abnormality if the distribution width is less than the criterion value, and determines that the sensor does not have abnormality if the distribution width is not less than the criterion value.

Abstract: A method for controlling an internal combustion engine of a motor vehicle. The method includes the use of an electronic control device for controlling the internal combustion engine in a motor vehicle, an irregular running determination unit for fault recognition, an injection quantity correction unit, a lambda probe associated with a defined group of cylinders, the injection quantity of a cylinder to be investigated of the defined group is adjusted in the direction of lean by a differential adjustment value associated with an irregular running differential value, and the injection value of at least one of the remaining cylinders, which are associated with the same lambda probe, is correspondingly adjusted in the direction of rich, so that in total a predetermined lambda value of this group of at least approximately 1 is reached.

Abstract: An engine control system includes a driver module and a diagnostics module. The driver module includes a high-side driver and a low-side driver, which selectively actuate a load. The driver module generates status signals based on detection of each of a plurality of failure modes of the high-side and low-side drivers. The diagnostics module increments a first error count for a first mode of the plurality of failure modes when the status signals indicate the driver module has detected the first mode. The diagnostics module increments a corresponding total count each time the driver module analyzes the first mode. The diagnostics module sets a fail state for a diagnostic trouble code (DTC) when the first error count for the first mode reaches a first predetermined threshold prior to the total count reaching a second predetermined threshold.

Abstract: A switching element is connected between a heater of an oxygen sensor and a ground in series. A voltage sensing resistor is connected in parallel with the switching element and in series with the heater. When the switching element is in a de-energization state, if the heater degrades and a resistance of the heater changes, a heater terminal voltage (potential at middle point between heater and voltage sensing resistor) changes correspondingly. Therefore, when the switching element is in the de-energization state, a heater terminal voltage determination parameter changing in accordance with the heater terminal voltage is sensed, and a degradation determination value corresponding to a battery voltage and temperature of the heater is calculated from a map. The heater terminal voltage determination parameter is compared with the degradation determination value to determine whether the heater has degraded.

Abstract: A control apparatus which can improve the accuracy of control of a controlled variable by a control input exhibiting a periodic fluctuating behavior. The control apparatus calculates an air-fuel ratio correction value DKCMD such that the output from an oxygen concentration sensor converges to a target output, and calculate a modulated value DKCMD_DSM by modulating DKCMD with an algorithm to which is applied a ? ? modulation algorithm. Further, the control apparatus calculates a reference air-fuel ratio KCMDBS according to an exhaust gas volume, calculates a model modification coefficient KTRQFF using a modification coefficient calculated such that DKCMD become equal to 0, calculates an adaptive reference air-fuel ratio KCMDADP by the equation of KCMDADP=KCMDBS×KTRQFF, and calculates a target air-fuel ratio KCMD by the equation of KCMD=KCMADP+DKCMD_DSM.

Abstract: An exhaust gas sensor for detecting oxygen concentration in exhaust gas is disposed in an exhaust pipe of an internal combustion engine. The sensor including a heater is controlled by a system that includes an electronic control unit. Water vapor contained in the exhaust gas is condensed on the sensor when the exhaust gas temperature is low. If the water condensation occurs while the sensor is heated by the heater, a sensor element may be cracked due to local cooling by the condensed water. To avoid the water condensation, the exhaust gas temperature is raised by retarding ignition timing of the engine for a certain period after the engine is started. After the exhaust gas is heated to a certain level, the sensor is heated. Alternatively, heating of the sensor is prohibited until the exhaust gas temperature becomes to a level at which no water condensation occurs. Thus, the cracking of the sensor element is avoided while making a delay of sensor activation minimal.

Abstract: A method of controlling an internal combustion engine having a fuel vapor purging system and a fuel delivery system including a fuel pump and a fuel pressure sensor for detecting the fuel pressure provided by the fuel pump is disclosed. In one example, the method includes, during a degraded condition of the fuel pressure sensor, adjusting the fuel pump output in response to an operating condition, adjusting at least one of a condition of the fuel vapor purging system and adaptive learning of a characteristic of the fuel delivery system; and further adjusting the fuel pump output in response to an output of an exhaust gas sensor while also adjusting an amount of fuel injected into a cylinder of the engine in response to said output of the exhaust gas sensor.

Abstract: In a diagnosis apparatus for an internal combustion engine which determines the abnormality of a linear A/F sensor which is disposed on the upstream side of a catalyst of the engine and detects the A/F of exhaust gas, the apparatus includes a response/gain deterioration detection unit that separately detects the response deterioration in which the response of the linear A/F sensor is delayed and the gain deterioration in which the detection sensitivity of the linear A/F sensor is abnormal.

Abstract: In an abnormality diagnostic device and an abnormality diagnostic device for an air-fuel ratio sensor that detects the air-fuel ratio of exhaust gas of an internal combustion engine, a system extending from a fuel injection valve to the air-fuel ratio sensor is model by a first order response delay, and a parameter in the first order response delay is identified based on an input air-fuel ratio that is given to the air-fuel ratio sensor and an output air-fuel ratio that is output from the air-fuel ratio sensor. Then, the presence/absence of abnormality regarding a predetermined characteristic of the air-fuel ratio sensor is determined based on the parameter identified. Thus, abnormality is diagnosed regarding individual characteristics of the air-fuel ratio sensor.

Abstract: A control device for an engine includes an air-fuel ratio detector detecting an air-fuel ratio of an exhaust gas of the engine. A feedback controller performs a feedback control of an amount of a fuel injection of mixed fuel including alcohol so that the air-fuel ratio detected by the air-fuel ratio detector is come close to a target air-fuel ratio, the mixed fuel supplied from a fuel feeder. A concentration estimator estimates a concentration of the alcohol in the mixed fuel based on the air-fuel ratio of the exhaust gas and a correction amount for the amount of the fuel injection controlled by the feedback control. A malfunction determiner determines that the fuel feeder has a malfunction when the correction amount is greater than or equal to a value for a period which is longer than a first period in a second period. The second period is from a first time point when the feedback controller starts to perform the feedback control.

Abstract: A system extending from a fuel injection valve to an air-fuel ratio sensor is modeled by using a first order response delay element. Parameters of the first order response delay element T, k are identified based on an input u(t) based on an input air-fuel ratio that occurs when the input air-fuel ratio is relatively sharply changed in accordance with an engine operation requirement, and an output y(t) of the air-fuel ratio sensor that changes in response to a change in the input air-fuel ratio. Then, an abnormality of characteristics (response rate and output) of the air-fuel ratio sensor is determined based on the identified parameter.

Abstract: When an ignition key is switched off, an updated learning value is set as an immediately preceding learning value of a present trip, which is compared with an average value of start timing learning values in a predetermined number of trips up to and including the present trip. When a difference between the immediately preceding learning value of the present trip and the average value exceeds a predetermined range, a start timing learning value to be used at a startup of a next trip is not updated. When the difference between the immediately preceding learning value of the present trip and the average value fails within the predetermined range, the immediately preceding learning value of the present trip is written in an EEPROM and used as the start timing learning value at the engine startup of the next trip.

Abstract: An abnormality diagnostic device for an air-fuel ratio sensor that detects the air-fuel ratio of exhaust gas of an internal combustion engine is provided. The abnormality diagnostic device includes: a device that an device that models a system extending from a fuel injection valve to the air-fuel ratio sensor by using a first order response delay element and a waste time element, and that identifies at least a waste time of the waste time element based on an input given to the air-fuel ratio sensor and an output obtained from the air-fuel ratio sensor; and another device that performs determination about an abnormality of the waste time based on the identified waste time.

Abstract: When an abnormality occurred in a SCR device is detected, the output of an engine is restricted. To this end, in one embodiment, at the time of an abnormality occurrence, a map adopted for calculating a fuel injection quantity is switched from that for a normal time (S407). Further, as the abnormality to be detected, the clogging of an injection nozzle, the dilution of urea water stored in a tank, or the like is adopted.

Abstract: A control device for an engine includes an air-fuel ratio detector detecting an air-fuel ratio of an exhaust gas of the engine. A feedback controller performs a feedback control of an amount of a fuel injection of mixed fuel including alcohol so that the air-fuel ratio detected by the air-fuel ratio detector is come close to a target air-fuel ratio, the mixed fuel supplied from a fuel feeder. A concentration estimator estimates a concentration of the alcohol in the mixed fuel based on the air-fuel ratio of the exhaust gas and a correction amount for the amount of the fuel injection controlled by the feedback control. A malfunction determiner determines that the fuel feeder has a malfunction when the correction amount is greater than or equal to a value for a period which is longer than a first period in a second period. The second period is from a first time point when the feedback controller starts to perform the feedback control.

Abstract: A method to determine degradation of a humidity sensor used for controlling an engine of a vehicle, the humidity sensor exterior to a passenger compartment of the vehicle, the method comprising determining whether to enable monitoring of the sensor based on a duration since vehicle operation; and in response to a determination to enable monitoring, comparing a signal from a second humidity sensor to a signal from the humidity sensor exterior to said passenger compartment of the vehicle to determine whether either of sensors has degraded.

Abstract: A fuel injection system designed to execute a learning operation to spray fuel through fuel injectors at each of given pressures of the fuel to determine the quantity of fuel sprayed actually from each of the fuel injectors (i.e., an actual injection quantity) into an internal combustion engine. The system calculates a deviation of each of the actual injection quantities from a target quantity to determine an injection correction value required to eliminate such a deviation. The system determines whether each of the injection correction values has an error or not and analyzes the mode in which the errors appear at the injection correction values to specify types of malfunction occurring in the system. The system relearns ones of the injection correction values as determined to have the errors.

Abstract: A sensor control device is connected with a plurality of exhaust sensors including an NOx sensor to be disposed around a catalyst, and is constructed such that a plurality of drive control circuits to be connected in a one-to-one relationship with the individual gas sensors are disposed in one casing. The sensor control device is provided with a communication output section that outputs signals through a digital communication line so that the signal transmissions/receptions with an ECU may be executed through the digital communication line. This digital communication line is physically a one-system cable but can transmit and receive signals of a plurality of kinds with predetermined communication protocols.

Abstract: A correction apparatus for correcting an output of an oxygen sensor installed in an exhaust pipe of an internal combustion engine to measure the concentration of oxygen contained in exhaust gas. The apparatus works to execute a fuel cut operation to bring the pressure in the exhaust pipe to the atmospheric pressure and enters an under-atmosphere correction mode to sample an output of the oxygen sensor and determine a correction factor compensating for a deviation of the sampled output from a reference value representing an actual concentration of oxygen. The apparatus also works to calculate the pressure in the exhaust pipe after start of the fuel cut and determine whether the under-atmosphere correction mode is to be entered or not based on the pressure of exhaust gas, thereby ensuring the accuracy in correcting the output of the oxygen sensor regardless of a variation in the pressure of exhaust gas.

Abstract: An exhaust gas discharged from a combustion chamber of each cylinder flows near an air-fuel ratio sensor via a junction. An ECU estimates an air-fuel ratio of each cylinder based upon a sensing value of an air-fuel ratio sensor. When a variation in the air-fuel ratio among the cylinders is equal to or greater than a predetermined value, the ECU determines that an abnormality exists in the air-fuel ratio. When a quantity of the exhaust gas discharged from each cylinder is less than another predetermined value, an intake air quantity is increased and ignition timing is delayed before the determination of presence or absence of the abnormality.

Abstract: If improper fuel (light oil or kerosene) is mixed into fuel (gasoline) supplied to the engine, a knock limit of an ignition timing is retarded. Based on such a characteristic, every when knocking is detected based on a detection signal from a knock sensor, the ignition timing is stored as the knock occurring ignition timing and the ignition timing is retarded by a predetermined amount. After repeating the above processes, it is determined whether the knock occurring ignition timing is retarded more than a determination value (for example, a retarded limit value of the knock occurring ignition timing in a case that proper gasoline is served). When the knock occurring ignition timing is retarded more than the determination value, it is determined that the improper fuel is mixed in the fuel.

Abstract: Air/fuel imbalance monitoring systems and methods for monitoring air/fuel ratio imbalance of an internal combustion engine having a plurality of engine cylinders are provided herein. An example of the method may include routing exhaust gas from a first group of cylinders to an exhaust gas oxygen sensor, and during selected operating conditions, indicating that air/fuel of at least one cylinder in the first group is imbalanced based on a response of the exhaust gas oxygen sensor at frequencies at or above firing frequency of the cylinders in the first group. An example of the system may include an exhaust gas oxygen sensor positioned in such a way that exhaust gas from the group of engine cylinders are routed to the exhaust gas oxygen sensor, and a controller configured to during selected operating conditions, indicate that air/fuel of at least one cylinder in the group is imbalanced based on a response of the exhaust gas oxygen sensor at frequencies at or above firing frequency of the cylinders in the group.

Abstract: Provision is made to avoid a fuel discharge timing and a fuel injection timing during the ordinary operation of the engine from being limited, by, upon the activation of an engine, making a high-pressure fuel pump perform high-pressure-fuel discharge operation prior to initial fuel discharge operation by a fuel injection valve and based on the condition of the resultant fuel-pressure rise, performing a diagnosis on whether or not a malfunction exists in a high-pressure fuel system.

Abstract: In a method for operating an internal combustion engine, a sensor for detecting and/or an actuator for setting a performance quantity of the internal combustion engine is/are monitored for the presence of a malfunction. Monitoring is performed at a first operating point of the internal combustion engine at a lower load and at an operating point of the internal combustion engine at a higher load. The two operating points are set alternatingly, and at least one of the two operating points is set multiple times for a single monitoring operation.

Abstract: In order to operate an internal combustion engine, a value of an operating variable of the internal combustion engine is determined depending on at least one measured quantity of the internal combustion engine. A test is carried out to determine whether or not the value of the operating variable is plausible depending on at least one second measured quantity of the internal combustion engine. If the value of the operating variable is implausible, a test is carried out to determine whether or not the internal combustion engine is currently being operated in lean operation. If the internal combustion engine is currently being operated in lean operation, a changeover to the quasi-stoichiometric operation of the internal combustion engine is implemented. After the changeover to the quasi-stoichiometric operation, the value of the operating variable is determined anew and tested anew. A changeover to lean operation is carried out anew if the newly determined value of the operating variable is plausible.

Abstract: A failure diagnostic apparatus is provided with an offset power source for offsetting a ground-side voltage of an air-fuel ratio sensor, an activation state judging unit for judging whether the air-fuel ratio sensor is active, a failure diagnosing unit for judging for a failure from an offset-added output signal of the air-fuel ratio sensor in a period when the activation state judging unit judges that the air-fuel ratio sensor is active, an input resistance switching unit for switching the level of an input signal from the air-fuel ratio sensor when the failure diagnosing unit has detected a failure in the air-fuel ratio sensor, and a failure state judging unit for determining a type of failure of the air-fuel ratio sensor on the basis of a voltage level obtained when the input resistance switching unit has switched the input signal level.

Abstract: In a compression ignition internal combustion engine provided with an NOx storage-reduction catalyst on an exhaust system, when the air fuel ratio of the exhaust gas being in a lean state is controlled to a rich state, a response time (ResS) from a time point an air fuel ratio sensor detects a first air fuel ratio (AF1), which is leaner than a stoichiometric air fuel ratio (AFS), to a time point the air fuel ratio sensor detects a second air fuel ratio (AF2), which is equal to or leaner than the stoichiometric air fuel ratio (AFS) and richer than the first air fuel ratio (AF1). When the response time (ResS) exceeds a stoichiometric air fuel ratio shift reference time (StdS), a determination is made that the air fuel ratio sensor is degraded.

Abstract: An abnormality diagnostic device for an air-fuel ratio sensor that detects the air-fuel ratio of exhaust gas of an internal combustion engine is provided. The abnormality diagnostic device includes: a device that an device that models a system extending from a fuel injection valve to the air-fuel ratio sensor by using a first order response delay element and a waste time element, and that identifies at least a waste time of the waste time element based on an input given to the air-fuel ratio sensor and an output obtained from the air-fuel ratio sensor; and another device that performs determination about an abnormality of the waste time based on the identified waste time.

Abstract: A system and method for utilizing a humidity sensor with an internal combustion engine of a vehicle is described. Specifically, information from the humidity sensor is used to adjust a desired air-fuel ratio to reduce engine misfire while improving vehicle fuel economy. Further, such information is also used to adjust timing and/or lift of the valve in the engine cylinder. Finally, diagnostic routines are also described.

Abstract: A fuel injection controller calculates a fuel pressure-feeding start angle of a fuel pump as a valve opening start angle of a metering valve, which regulates a discharge amount, by adding a base angle and a feedback correction value. The base angle is calculated in accordance with a command injection amount and target fuel pressure based on a basic map. The feedback correction value is calculated based on differential pressure between sensed fuel pressure and the target fuel pressure. If an abnormality is caused in either one of two metering valves, the base angle is calculated based on an abnormal period map instead of the basic map. Thus, controllability of the fuel pressure is maintained high even when the abnormality is caused in a part of multiple pressure-feeding systems including multiple plungers of the fuel pump.

Abstract: A diagnosis device calculates a lean-direction responsiveness characteristic and a rich-direction responsiveness characteristic of the exhaust gas sensor. The lean-direction responsiveness represents a responsiveness of the sensor in a case that an air-fuel ratio is controlled in such a manner as to be varied in a lean direction. The rich-direction responsiveness represents a responsiveness of the sensor in a case that the air-fuel ratio is controlled in such a manner as to be varied in a rich direction. The diagnosis device determines whether the exhaust gas sensor deteriorates based on at least one of the lean-direction responsiveness characteristic and the rich-direction responsiveness characteristic, and on a comparison result between the lean-direction responsiveness characteristic and the rich-direction responsiveness characteristic.

Abstract: A system and method for utilizing a humidity sensor with an internal combustion engine of a vehicle is described. Specifically, information from the humidity sensor is used to adjust a desired air-fuel ratio to reduce engine misfire while improving vehicle fuel economy. Further, such information is also used to adjust timing and/or lift of the valve in the engine cylinder. Finally, diagnostic routines are also described.

Abstract: An element crack detecting apparatus for an oxygen sensor detects a sensor output voltage for an abnormality detection period after a fuel cut-off is started during operation of an engine. When the output voltage becomes negative, an abnormality counter is counted up. When the abnormality counter value reaches a determination value, it is determined that the element crack is present. The abnormality detection period is variably set in response to an engine rotational speed, an intake air quantity and the mixture state immediately before the fuel cut-off is effected. The determination value is variably set in response to the oxygen sensor temperature and the mixture state immediately before the fuel cut-off is effected. Further, the determination value is variably set in response to a magnitude of the negative voltage of the oxygen sensor.

Abstract: An abnormality detecting apparatus includes an air/fuel ratio sensor that detects an air/fuel ratio within a range including the stoichiometric air/fuel ratio, an admittance detector for detecting an admittance of the sensor, and a temperature detector for detecting a temperature of the sensor. This apparatus detects an abnormality of the sensor when the detected temperature is at a first temperature which is higher than an activation temperature of the sensor and the detected admittance is less than a first determining value. The apparatus also detects a disconnection abnormality of the sensor when the detected temperature is at a second temperature, which is higher than a minimum temperature at which admittance can be detected for a normally operation and lower than the first temperature, and the detected admittance is less than a second determining value for determining disconnection of the sensor which is less than the first determining value.

Abstract: In a multi-cylinder engine, to compute the air-fuel ratio of each cylinder by an air-fuel ratio sensor disposed in an exhaust pipe, a cylinder is determined by a crank angle detected by a crank angle sensor. A deviation in the air-fuel ratio of each cylinder is detected on the basis of the output signal of the air-fuel ratio sensor disposed in the exhaust pipe and the forcibly changed quantity of the air-fuel ratio.

Abstract: A method for detecting combustion misfires of an internal combustion engine and a device for carrying out the method, in which an evaluation of a lambda signal made available by at least one broadband lambda sensor is provided. The lambda signal is compared to a lambda signal threshold value. A warning signal is made available in response to the exceeding of a threshold in the direction of lean combustion. The procedure especially makes possible the detection of continual misfires which occur, for example, in response to an error in the air supply to the internal combustion engine and/or because of a lack of fuel. The procedure makes possible the detection of dangerous situations for at least one exhaust gas treatment device that is present, which may be removed by introducing protective measures, error warnings and error memory entries.

Abstract: An air-fuel ratio sensor monitor is provided which is designed to monitor reactive characteristics or response rates of an air-fuel ratio sensor when an air-fuel ratio of a mixture to an internal combustion engine is changing to a rich side and to a lean side. The monitored response rates are used in determining whether the sensor is failing or not, in determining the air-fuel ratio of the mixture accurately, or in air-fuel ratio control of the engine.

Abstract: A method of resetting an active emissions system error indicator associated with a vehicle. The method comprises performing at least a first requesting step, where the requesting step is performed indirectly by using a record mode function until said active e emissions system error indicator resets in response to the requesting step. In one embodiment an additional step comprises the additional step of performing at least a second requesting step for a second type of information, the second requesting step performed either manually or by the record mode function. In a particular embodiment of the invention, an electronic tool, such as a bi-directional scan tool, is used to perform the firsgt and second requesting steps.

Abstract: When carrying out abnormality determination for an air-fuel ratio sensor 33 by comparison of an average value tave of all diagnostic values t(n) and an abnormality determination value C, the abnormality determination value C is corrected using an average value ?tave for the disturbance correction values ?t(n). A disturbance correction value ?t(n) is derived by subtracting a correction reference value A, which is a diagnostic value with a normal air-fuel ratio sensor 33 when there is no disturbance, from the diagnostic value t(n). The present invention provides the abnormality diagnosis device for the air-fuel ratio sensor that can acquire highly precise diagnosis results without lowering frequency of diagnosis accurately taking into consideration the influence of disturbance.

Abstract: The invention relates to a method for monitoring a control unit of an internal combustion engine, according to which a variable, which characterises the initial parameter of a lambda regulation system, is monitored for a deviation from a predefined threshold value. An error response takes place in accordance with the deviation that has been determined.