Abstract: A gas sensor detects the concentration of a specific gas on the basis of a pump current that flows when oxygen is pumped out from a measurement chamber, so that an oxygen concentration in the measurement chamber becomes a predetermined low concentration, the oxygen that is pumped out being oxygen that is generated when the specific gas is reduced in measurement chamber in a case where the specific gas is an oxide or being oxygen that is generated when a gas obtained as a result of conversion of the specific gas to an oxide is reduced in the measurement chamber in a case where the specific gas is a non-oxide. Further, the gas sensor corrects the pump current or the concentration of the specific gas on the basis of the oxygen concentration of the measurement-object gas when the measurement-object gas is in a rich atmosphere.

Abstract: A method for estimating the ageing of an exhaust gas sensor (16) placed in an exhaust line (14) of a diesel internal combustion engine (10) of an industrial vehicle (1) includes: —acquiring (S100) an initial value of an estimated remaining lifetime (50) of the exhaust gas sensor; —measuring (S102) the time spent by the engine in each of several predefined engine operation modes during a predefined time period; —for each of the engine operation modes, calculating (S104) a lifetime loss value depending on the time spent by the engine in said engine operation mode during the predefined time period and on a predefined ageing rate associated to said engine operation mode; —updating (S106) the estimated remaining lifetime value by subtracting each calculated lifetime loss value from the initial value.

Abstract: The abnormality diagnosis system 1, 1?, 1? of an ammonia detection device 46, 71 comprises: an air-fuel ratio detection device 41, 72 arranged in the exhaust passage 22 at the downstream side of the catalyst 20; an air-fuel ratio control part 51 configured to control an air-fuel ratio of exhaust gas; and an abnormality judgment part 52 configured to judge abnormality of the ammonia detection device. The air-fuel ratio control part performs rich control making the air-fuel ratio of the inflowing exhaust gas richer than a stoichiometric air-fuel ratio. The abnormality judgment part judges that the ammonia detection device is abnormal if, after start of the rich control, an output value of the ammonia detection device does not rise to a reference value before the air-fuel ratio detected by the air-fuel ratio detection device falls to a rich judged air-fuel ratio richer than a stoichiometric air-fuel ratio.

Abstract: A method for diagnosing a lambda sensor during ongoing operation. It includes energizing the lambda sensor using a pump current pulse additive to a pump current and a pump current counter pulse additive to the pump current and ascertaining a malfunction of the lambda sensor from voltages, which are measured at a pump cell and/or a Nernst cell of the lambda sensor during the energization by the pulses.

Abstract: According to some embodiments, the present disclosure may relate to a system including a gaseous fuel consuming engine operating at an air to fuel ratio (AFR) and including a throttle valve controlling a speed of engine, and an engine controller coupled to the engine. The engine controller may be configured to obtain the speed of the engine and obtain the AFR of the engine. The engine controller may also be configured to, based on a transient event affecting the engine, coordinate modification of both the throttle valve to change the speed of the engine and trim valve to change the AFR of the engine to maintain at least one of the speed and the AFR of the engine within a threshold deviance.

Abstract: A controller of an air-fuel-ratio sensor according to an embodiment includes a current supplying unit, a sweep processing unit, and an abnormality detecting unit. The current supplying unit supplies a current to the pump cell through a first terminal connected with the pump cell so as to control the pump cell. The sweep processing unit executes a sweeping process in which a predetermined voltage or a predetermined current is applied to the detection cell through a second terminal connected with the detection cell so as to change a voltage and a current of the detection cell. The abnormality detecting unit detects a short-circuited state between the first terminal and the second terminal on the basis of a fluctuation in a voltage or a current, generated by the sweeping process, of the first terminal.

Abstract: An internal combustion engine comprises an exhaust purification catalyst and an air-fuel ratio sensor arranged at a downstream side of the exhaust purification catalyst, stops or decreases a feed of fuel as fuel cut control, and controls an air-fuel ratio of exhaust gas to a rich air-fuel ratio after the end of the fuel cut control as post reset rich control. The diagnosis system calculates a first characteristic of change of air-fuel ratio at the time when the output air-fuel ratio first passes a first air-fuel ratio region leaner than a stoichiometric air-fuel ratio and a second characteristic of change of air-fuel ratio at the time when the output air-fuel ratio first passes a second air-fuel ratio region including a stoichiometric air-fuel ratio. The diagnosis system diagnoses the abnormality of the air-fuel ratio sensor based on the first characteristic of change of air-fuel ratio and the second characteristic of change of air-fuel ratio.

Abstract: A method for controlling a fill level of a catalytic converter that is in an exhaust aftertreatment system of an exhaust tract downstream from an internal combustion engine includes an exhaust gas sensor that is upstream of the catalytic converter measuring, and producing a signal representing, a concentration of an exhaust component; correcting a dynamic distortion present in the produced signal to produce a corrected signal; determining the fill level of the catalytic converter by inputting the corrected signal into a modeling function; and performing a control that modifies the fill level based on the determined fill level.

Abstract: A system for identifying a vehicle includes an input interface and a processor. The input interface is configured to receive traffic from a vehicle bus. The processor is configured to determine a data fingerprint from the traffic; and determine an identifier for the vehicle from the fingerprint.

Abstract: A sensor control apparatus controls a gas sensor which measures the concentration of oxygen contained in exhaust gas. A current DA converter of the sensor control apparatus supplies a current having a current value designated by a control section (hereinafter referred to as the designated current value) to a label resistor having a resistance previously set so as to represent the characteristic of the gas sensor (hereinafter referred to as the characteristic resistance). Further, the control section of the sensor control apparatus sets the designated current value to a plurality of values in accordance with the characteristic resistance of the label resistor.

Abstract: An abnormality determination device includes an injection instructor that realizes a rich state of an air-fuel ratio in an exhaust gas by sending an instruction of (i) stopping an application of bias to a plus terminal and (ii) adjusting a fuel injection amount from an injector. The abnormality determination device also includes an abnormality determiner that distinctively determines abnormality of, i.e., in terms of which one of, the plus terminal or a minus terminal having a short circuit to a power supply or a ground failure by detecting an electromotive force of an air-fuel ratio sensor when the air-fuel ratio in the exhaust gas is in the rich state according to the instruction of the injection instructor.

Abstract: The abnormality diagnosis system of an air-fuel ratio sensor comprising an exhaust purification catalyst, an upstream side air-fuel ratio sensor provided at an upstream side of the exhaust purification catalyst, a downstream air-fuel ratio sensor provided at a downstream side of the exhaust purification catalyst, and a diagnosis device diagnosing the downstream air-fuel ratio sensor for abnormality based on outputs of these air-fuel ratio sensors. The diagnosis device judges that the downstream air-fuel ratio sensor suffers from an abnormality if the output air-fuel ratio of the upstream side air-fuel ratio sensor has become a rich air-fuel ratio richer than a stoichiometric air-fuel ratio, and the output air-fuel ratio of the downstream air-fuel ratio sensor air-fuel ratio has changed from an air-fuel ratio richer than a lean judged reference air-fuel ratio to an air-fuel ratio leaner than the lead judged reference air-fuel ratio.

Abstract: Methods and systems include determining a cylinder air-fuel ratio imbalance in a multi-cylinder engine. In one example, the method may include sequentially firing an engine cylinder to provide an expected air-fuel deviation and learning cylinder air-fuel ratio imbalance based on an error between an actual air-fuel ratio deviation from a maximum lean air-fuel ratio relative to an expected air-fuel deviation during a deceleration fuel shut-off event.

Abstract: An abnormality diagnosis system of an air-fuel ratio sensor is provided with an exhaust purification catalyst, an upstream side air-fuel ratio sensor which is provided at an upstream side of the exhaust purification catalyst, a downstream side air-fuel ratio sensor which is provided at a downstream side of the exhaust purification catalyst, and a diagnosis device which uses the outputs of these air-fuel ratio sensors as the basis to diagnose abnormality of the downstream side air-fuel ratio sensor.

Abstract: An internal combustion engine comprises: an exhaust purification catalyst; a downstream side air-fuel ratio sensor which is arranged at a downstream side of the exhaust purification catalyst; and an air-fuel ratio control system which performs feedback control so that the air-fuel ratio of the exhaust gas flowing into the exhaust purification catalyst becomes a target air-fuel ratio.

Abstract: In a control system for an internal combustion engine in which an exhaust gas purification catalyst having a lower catalyst layer and an upper catalyst layer disposed at the upper side of the lower catalyst layer is arranged in an exhaust passage of the internal combustion engine, when an operation at a rich air fuel ratio is switched to an operation at a target lean air fuel ratio, switching is made through a first operation in which the air fuel ratio of exhaust gas is temporarily made into a lean air fuel ratio, and a second operation which is carried out after the first operation and in which the air fuel ratio of the exhaust gas is made to change alternately between the rich air fuel ratio and the lean air fuel ratio a plurality of times, whereby the HC poisoning of the catalyst can be recovered at an early stage.

Abstract: An O2 sensor includes a sensor element using a solid electrolyte layer and a pair of electrodes placed at a position to interpose the solid electrolyte layer, detects an exhaust gas from an internal combustion engine as an object of a detection, and outputs an electromotive force signal depending on an air-fuel ratio of the exhaust gas. The sensor element is connected with a constant current circuit supplying a constant current that is prescribed. A microcomputer calculates an element resistance, determines whether the air-fuel ratio is at least rich, lean, or stoichiometric, on the basis of a comparison between an electromotive force output of the electrogenic cell and a prescribed threshold. Further, the microcomputer controls the constant current supplied by the constant current circuit on the basis of the element resistance.

Abstract: An O2 sensor includes a sensor element using a solid electrolyte layer and a pair of electrodes placed at a position to interpose the solid electrolyte layer, detects an exhaust gas from an internal combustion engine as an object of a detection, and outputs an electromotive force signal depending on an air-fuel ratio of the exhaust gas. The sensor element is connected with a constant current circuit supplying a constant current that is prescribed. A microcomputer conducts an abnormality diagnosis of an output response of the sensor element on the basis of a state of variation in an electromotive force output. Further, when the microcomputer conducts the abnormality diagnosis, the microcomputer restricts a supply of the constant current by the constant current circuit before conducting the abnormality diagnosis.

Abstract: Methods and systems are provided for a diagnostic of a humidity sensor positioned in an intake of an engine and adjusting engine operation responsive to findings of the diagnostic. In one example, the method may include sealing a vehicle exhaust system of an engine, combusting fuel at cylinders of the engine while flowing gases through the engine in a first direction, and then, flowing the combusted exhaust gases through the engine in a reverse, second direction to the humidity sensor positioned in the intake. The method may further include indicating degradation of the humidity sensor based on the output of the humidity sensor while flowing gases in the first and second directions.

Abstract: An abnormality diagnosis system of an air-fuel ratio sensor 40 or 41 provided in an exhaust passage of an internal combustion engine and generating a limit current corresponding to an air-fuel ratio, comprises a current detecting part 61 detecting an output current of the air-fuel ratio sensor and an applied voltage control device 60 controlling a voltage applied to the air-fuel ratio sensor. The abnormality diagnosis system applies a voltage inside a limit current region where a limit current is generated and a voltage outside the limit current region to the air-fuel ratio sensor when the air-fuel ratio of the exhaust gas circulating around the air-fuel ratio sensor is made a predetermined constant air-fuel ratio, and judges a type of abnormality occurring at the air-fuel ratio sensor based on an output current of the air-fuel ratio sensor detected by the current detecting part at this time.

Abstract: A control device of an internal combustion engine according to the present invention executes air-fuel ratio control based on an output of an air-fuel ratio sensor provided at an upstream side of a catalyst, with correction based on an output of an oxygen sensor at a downstream side of the catalyst. When it is determined that a degree of an output tendency in a predetermined lean region is not less than a predetermined lean degree, and that a degree of an output tendency in a predetermined rich region is less than a predetermined rich degree based on lean tendency and rich tendency values representing output tendencies of the oxygen sensor, a limit is set to the correction in a direction to more suppress enriching of an air-fuel ratio as a degree is larger in which the output of the oxygen sensor is shifted to a lean side.

Abstract: Downstream side air-fuel ratio sensor signal based adaptive air-fuel ratio control. When the air-fuel ratio detected by the downstream side air-fuel ratio sensor is maintained lean unduly, a stuck learning control is performed to decrease a learning value to lower the air-fuel ratio. Adaptive learning value update control is performed based on the downstream side air-fuel ratio sensor signal to increase the learning value when an upstream air-fuel ratio deviates to the rich side and to decrease the learning value when the upstream air-fuel ratio deviates to the lean side. It is judged that the downstream side air-fuel ratio sensor is abnormal when a certain value or more of decrease of the learning value and a certain value or more of increase of the learning value are repeated.

Abstract: An abnormality diagnosis device is for an exhaust gas sensor that detects an air-fuel ratio, or a rich or lean state of exhaust gas from an internal combustion engine and that includes a sensor element having a catalyst layer. The device includes an abnormality diagnosis unit that makes a sensor abnormality diagnosis whereby to change the air-fuel ratio alternately between a rich side and a lean side and to determine whether the exhaust gas sensor is abnormal or not based on response characteristics of the exhaust gas sensor in response to the change of the air-fuel ratio. When making the sensor abnormality diagnosis, the abnormality diagnosis unit calculates the response characteristics of the exhaust gas sensor with exclusion of a sensor output plateau region, which is a region in which an output of the exhaust gas sensor is stagnant due to the catalyst layer.

Abstract: An internal combustion engine comprises an exhaust purification catalyst and an air-fuel ratio sensor arranged at a downstream side of the exhaust purification catalyst, stops or decreases a feed of fuel as fuel cut control, and controls an air-fuel ratio of exhaust gas to a rich air-fuel ratio after the end of the fuel cut control as post reset rich control. The diagnosis system calculates a first characteristic of change of air-fuel ratio at the time when the output air-fuel ratio first passes a first air-fuel ratio region leaner than a stoichiometric air-fuel ratio and a second characteristic of change of air-fuel ratio at the time when the output air-fuel ratio first passes a second air-fuel ratio region including a stoichiometric air-fuel ratio. The diagnosis system diagnoses the abnormality of the air-fuel ratio sensor based on the first characteristic of change of air-fuel ratio and the second characteristic of change of air-fuel ratio.

Abstract: A method for checking fault detection of a control device of an internal combustion engine for malfunction of a connected broadband lambda probe, including checking with a fault simulator between the lambda probe and the control device; to simulate faults of the broadband lambda probe, the fault simulator modifies electrical signals between the broadband lambda probe and the control device. A Nernst voltage of the lambda probe and a pump current of the control device are delivered to the fault simulator; the fault simulator delivers a pump current to the lambda probe and a Nernst voltage to the control device; to simulate faults of the lambda probe, the fault simulator modifies the Nernst voltage to the control device as to the Nernst voltage outputted from the lambda probe. Also described is a related fault simulator. The method and fault simulator monitor the fault detection of control devices for lambda probes.

Abstract: A method for operating a compression ignition engine includes forming a combustible mixture by mixing generally homogeneously a first fuel and air and introducing this mixture into the at least one cylinder, compressing the combustible mixture with the piston in a compression stroke, injecting a second fuel to the combustible mixture at an injection-time of the second fuel during the compression stroke but before start of combustion, and continuing the compression stroke until combustion starts at those locations in the at least one cylinder where concentration of the second fuel is highest and/or the temperature of the mixture is the highest. Emission of the cylinder and/or mechanical stress of the cylinder caused by the combustion are monitored, and if emissions and/or mechanical stress are above respective predetermined thresholds, individually for the cylinder, the amount and/or the timing of the second fuel injected, and/or temperature of the cylinder charge is changed.

Abstract: An apparatus includes a stationary conditions circuit structured to received information indicative of a stationary condition of a vehicle having an exhaust aftertreatment system; an engine circuit structured to cause an elevated operating mode in response to the detection of the stationary condition; and a nitrous oxide (NOx) monitor reset circuit. The NOx monitor reset circuit may be structured to: receive vehicle operation data indicative of an enable condition for a NOx monitor reset process; in response to the enable condition, receive NOx data indicative of a NOx amount exiting the exhaust aftertreatment system as part of the NOx monitor reset process; compare the NOx data to an estimated NOx amount; and in response to the comparison, selectively diagnose the exhaust aftertreatment system as one of a healthy and a degraded exhaust aftertreatment system.

Abstract: A control device for an exhaust gas sensor includes first means for estimating a temperature of a sensor element in accordance with impedance of a solid electrolyte, and second means for estimating the temperature of the sensor element in accordance with resistance of a heater. A first element temperature according to impedance of the sensor element in a predetermined detection timing is detected by the first means, and a second element temperature according to resistance of a heater of the sensor element in the predetermined detection timing is detected by the second means. The control device corrects the temperature of the sensor element that is estimated in accordance with heater resistance by the second means in accordance with a difference between the first element temperature and the second element temperature.

Abstract: An electronic control module for operating an internal combustion engine is disclosed. The electronic control module is configured to monitor a first air-fuel equivalence ratio of engine exhaust gases upstream of a NOx trap, and to activate a diagnostic routine for the NOx trap when the first air-fuel equivalence ratio is smaller than one. The diagnostic routine enables the electronic control module to monitor a second air-fuel equivalence ratio of engine exhaust gases downstream of the NOx trap, to use the first and second air-fuel equivalence ratios to calculate an index that is representative of the conversion efficiency of the NOx trap, and to identify a failure of the NOx trap when the efficiency index is lower than a predetermined threshold value.

Abstract: A method for determining a lambda air ratio using a gas sensor having a ceramic measuring element, an output voltage of the gas sensor changing abruptly if lambda is changed in the range around lambda=1 and the gas sensor having an initial inverse voltage which is dependent on the temperature of the gas sensor. A threshold value for the initial inverse voltage is established for a limit between a lambda value below and above 1 as a function of the temperature of the gas sensor. Also described is a device for implementing the method. The method and the device make it possible to operate gas sensors having a ceramic measuring element at an even lower temperature than according to the related art and thus reduce the period between the start of an internal combustion engine and the operational readiness of a lambda regulation. This makes it possible to reduce the fuel consumption as well as the emission of undesirable components of the exhaust gas.

Abstract: In a turbocharged internal combustion engine, an amount of cylinder suction air is calculated with sufficiently high accuracy to suitably control the internal combustion engine in consideration of influences of an exhaust pressure on a volumetric efficiency equivalent value without requiring a huge memory capacity, in fewer adaptive man hours, and under a low operation load. A correction calculation parameter is calculated using an exhaust pressure, an exhaust pressure for pre-correction volumetric efficiency equivalent value, and an intake manifold pressure, and a post-corrected volumetric efficiency equivalent value is calculated by correcting a pre-correction volumetric efficiency equivalent value using the correction calculation parameter. An amount of air entering a cylinder from an intake manifold is calculated on the basis of the post-correction volumetric efficiency equivalent value.

Abstract: A method for diagnosing disconnection of an oxygen sensor includes measuring, by a controller, a voltage supplied to an oxygen sensor through a voltage divider; measuring a voltage of a reference cell of the oxygen sensor; determining whether the voltage supplied to the oxygen sensor and the voltage of the reference cell fall within a reference range from preset reference values, respectively; and determining that a ground wire of the oxygen sensor is disconnected, when the voltage of the oxygen sensor or the voltage of the reference cell deviates from the reference range.

Abstract: An apparatus for providing an error signal for a control unit, the error signal indicating a malfunction of a sensor unit. The apparatus includes an input module configured to receive a sensor signal from the sensor unit, the sensor signal being a periodic signal between an upper level and a lower level of a physical quantity. Further, the apparatus includes a determination module configured to determine the malfunction of the sensor unit and an output module configured to provide the error signal indicating the malfunction for the control unit. The error signal comprises a predetermined level of the physical quantity which differs from the upper level and from the lower level.

Abstract: A system according to the principles of the present disclosure includes an error count module and a sensor diagnostic module. The error count module increases an error count when an actual air/fuel ratio generated by an oxygen sensor monitoring an exhaust system of an engine is different than a desired air/fuel ratio. The error count module selectively adjusts a rate at which the error count is increased based on an ambient temperature. The sensor diagnostic module diagnoses a fault in the oxygen sensor when the error count is greater than a first predetermined count.

Abstract: To operate an internal combustion engine, a specified forced stimulation is applied to an air ratio as the basis for a target value of a lambda controller. In diagnostic operation, a diagnostic function is used to identify a probe error of the exhaust gas probe, and a value of the measurement signal is recorded as a start value in chronological correlation with an edge of the target value curve of the lambda controller and the current value of the measurement signal is recorded as an end value after a specified first time duration. The start and end values are used to determine whether a filter error or a dead time error of the exhaust gas probe exists. The first time duration is specified such that start value/end value difference for a filter error differs start value/end value difference for a dead time error by at least a specified difference value.

Abstract: An abnormality detecting device of an internal combustion engine according to the present invention includes a sensor nick abnormality detecting unit configured to detect a nick abnormality in a detecting element of a downstream side sensor which is provided in a downstream side of an exhaust gas purifying catalyst in an exhaust passage and generates an output corresponding to an oxygen concentration in exhaust gas, on the basis of a matter that a distribution of an output of the downstream side sensor is biased to an area in which the air-fuel ratio is leaner than a theoretical air-fuel ratio, and an inhibiting unit configured to inhibit detection of the nick abnormality of the detecting element by the sensor nick abnormality detecting unit in the case that an intake air amount exceeds a predetermined amount.

Abstract: A vehicle includes an internal combustion engine, an air-fuel ratio sensor provided in an exhaust passage of the internal combustion engine, and a controller. The controller is configured to diagnose a responsiveness of the air-fuel ratio sensor on the basis of an output voltage of the air-fuel ratio sensor in a predefined period. The period is a period over which exhaust gas goes through the air-fuel ratio sensor during the internal combustion engine is rotating without fuel injection.

Abstract: Some embodiments relate to an internal combustion engine that includes a combustion chamber and a rotating component. The internal combustion engine further includes a sensing system that detects an angular position of the rotating component. A controller calculates a ratio between air and fuel in the combustion chamber based on the detected position of the rotating component. As an example, the rotating component may be a crankshaft where the controller calculates a speed of the crankshaft and an acceleration of the crankshaft based on the detected position of the crankshaft.

Abstract: A sensor controller for a particulate matter detection sensor includes a signal output circuit connected to the particulate matter detection sensor such that a sensor detection value is changeable in a predetermined output range by the signal output circuit, a heater configured to heat an attachment portion so as to burn and remove particulate matter attached to the attachment portion, a learning portion for calculating a sensor standard value in a state where the resistance between a pair of opposed electrodes is reduced based on an obtained sensor detection value and for storing the sensor standard value as a learning value, and a correcting portion for correcting the sensor detection value based on the sensor standard value stored by the learning portion.

Abstract: Control systems and methods are for a marine engine emitting exhaust gas. A sensor senses a characteristic of the exhaust gas. An electrical heater heats the sensor. A control circuit monitors current drawn by the heater. The control circuit controls an operational characteristic of the engine based upon the characteristic of the exhaust gas and modifies its control of the operational characteristic of the engine when the current drawn by the heater changes by a predetermined amount.

Abstract: In a method for detecting the operational readiness of a jump lambda sensor associated with an internal combustion engine the internal resistance of the sensor is determined as the criterion for the operational readiness of the sensor. The internal resistance is measured by applying a pulsed current to the sensor, the frequency of the current being selected as a function of the state of the sensor (1, 2, 3, 4).

Abstract: An air-fuel ratio control system for an internal combustion engine has a perturbation control which oscillates the air-fuel ratio with a first frequency. A first difference signal is generated indicative of a difference between a present value and a first past value from an air-fuel ratio sensor detected at a timing of a first specific period which is set to reduce a specific frequency component corresponding to a specific frequency different from the first frequency. A first frequency component is extracted. A second difference signal is generated indicative of a difference between a present value and a second past value detected at a timing of a second specific period which is set to reduce the first frequency component. The specific frequency component is extracted. A failure of the control system is determined by a relationship between intensities of the first frequency component and the specific frequency component.

Abstract: Embodiments for indicating fuel rail temperature sensor degradation are provided. In one embodiment, an engine method comprises delivering gaseous fuel to a cylinder based on feedback from a fuel rail temperature sensor, and during select conditions, indicating fuel rail temperature sensor degradation based on a difference between measured fuel rail temperature and an expected temperature. In this way, measured fuel rail temperature may be correlated with other engine temperatures to detect sensor degradation.

Abstract: A method of monitoring an exhaust gas sensor coupled in an engine exhaust is provided. The method comprises indicating exhaust gas sensor degradation based on a difference between a first set of estimated parameters of a rich operation model and a second set of estimated parameters of a lean operation model, the estimated parameters based on commanded lambda and determined lambda values collected during selected operating conditions. In this way, sensor degradation may be indicated with data collected in a non-intrusive manner.

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: Embodiments provide systems and methods for using a feedback correction factor to determine whether a motor vehicle should be placed in a judging or non-judging mode regarding the on-board diagnostic system. If the feedback correction factor is within a predetermined range, the vehicle is placed in a judging mode. If the feedback correction factor is outside a predetermined range, the vehicle is placed in a non-judging mode. Methods and systems for using an engine oil temperature to determine whether a motor vehicle should be placed in a judging or non-judging mode regarding the on-board diagnostic system are disclosed. If an engine oil temperature, or predicted engine oil temperature, is below a predetermined temperature, the motor vehicle is placed in a non-judging mode. If an engine oil temperature, or predicted engine oil temperature, is above a predetermined temperature, the motor vehicle is placed in a judging mode.

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: Fuel reforming catalysts 28 generate a hydrogen-containing reformed gas when they come into contact with exhaust gas that contains a reforming fuel. Upstream and downstream air-fuel ratio sensors 58, 60 are respectively installed upstream and downstream of the fuel reforming catalysts 28. The upstream air-fuel ratio sensor 58 outputs a upstream sensor signal in accordance with oxygen concentration. The downstream air-fuel ratio sensor 60 outputs a downstream sensor signal in accordance with oxygen concentration and hydrogen concentration by using zirconia's oxygen detection capability and a change of a diffusion layer's hydrogen-concentration-dependent oxygen detection capability. An ECU 50 detects the hydrogen concentration without being affected by the oxygen concentration through the use of the upstream sensor signal in which only the oxygen concentration is reflected and the downstream sensor signal in which the oxygen concentration and hydrogen concentration are reflected.

Abstract: A trouble diagnosis device and method for an NOx sensor for determining abnormality of an NOx sensor used in an exhaust gas purification system. The device can perform a trouble diagnosis without forcedly creating a diagnosis mode during operation of an internal combustion engine and without deterioration of drivability or fuel consumption. The device detects the time-lapse variation of the exhaust NOx flow rate suitable for diagnosis in a normal operation mode and determines whether the NOx sensor responds with following this variation.

Abstract: An apparatus for determining a deterioration of a NOx sensor response rate in an internal combustion engine system includes an engine control module configured to stop fueling to an internal combustion engine during motoring of the internal combustion engine. The apparatus also includes a signal monitoring module configured to monitor a NOx sensor signal after the engine control module stops fueling to the internal combustion engine during motoring of the engine and store NOx sensor signal data corresponding to the monitored NOx sensor signal. Additionally, the apparatus includes a time constant module that is configured to determine a time constant of the NOx sensor response after the engine control module stops fueling. The apparatus further includes a response rate deterioration module configured to determine a response rate deterioration value of the NOx sensor based at least partially on the determined time constant.