Abstract: The present invention relates to a method for controlling an internal combustion engine arrangement (100). The internal combustion engine arrangement (100) comprises a combustion cylinder (102) and an inlet valve (106) arranged to be positioned in a closed position at a distance before a piston (104) reaches a bottom dead center during normal operation. The inlet valve is further controllable to be arranged in the open position until the piston reaches the bottom dead center if a required volumetric efficiency of the combustion cylinder is higher than a volumetric efficiency during normal operation.

Abstract: Systems and methods for determining fuel delay in a fuel injected engine with cylinders that may be deactivated are presented. In one example, the fuel injection delay is determined via a cylinder firing schedule array when the cylinder firing schedule array is available. The fuel injection delay is determined via weighted average of a fuel injection delay of a present engine cycle and a fuel injection delay of a past engine cycle when the cylinder firing schedule array is not available.

Abstract: A method for diagnosing deviation of an air-fuel ratio between cylinders using an oxygen sensor roughness, the method may include a diagnosis condition determination step, an oxygen sensor roughness determination activation step, an oxygen sensor roughness level determination step, an air-fuel ratio deviation detection step, and a failure reporting step.

Abstract: Methods and systems are provided for learning a cylinder-to-cylinder air variation. During conditions when a PFDI engine is operated in a port-injection only mode, prior to port fuel injection, a direct-injection fuel rail pressure may be lowered via direct-injection. Then, prior to a spark event in a port-injected cylinder, the direct-injector may be transiently opened to use the rail pressure sensor for estimating a cylinder compression pressure, and inferring cylinder air charge therefrom.

Abstract: Internal combustion engine having cam actuated valves that can be controlled to facilitate the use of different air charge levels in different cylinders or sets of cylinders are described. In one aspect a first set of cylinders is operated in a skip fire manner in which the corresponding cylinders are deactivated during skipped working cycles. Cam actuated intake valves associated with a second set of cylinders are operated differently so that the air charge in the cylinders in the second set is different than the air charge in fired cylinders subject to the skip fire control. According to another aspect, an engine having cam actuated intake valves is operated in a dynamic firing level modulation mode. During the dynamic firing level modulation operation, the cam actuated intake valves are controlled in at least two different manners to such that different cylinder working cycles have different air charges.

Abstract: A method for controlling intake and exhaust valves of an engine may include: determining, by a controller, a target opening duration of the intake and exhaust valves based on an engine load and an engine speed; modifying, by an intake continuous variable valve duration (CVVD) device and by an exhaust CVVD device, current opening and closing timings of the intake valve and/or exhaust valve based on the target opening duration of the valves; and advancing or retarding, by the intake and/or exhaust CVVD devices, the current opening timing of the intake and exhaust valves while simultaneously retarding or advancing the current closing timing of the intake and exhaust valve by a predetermined value based on the target opening duration.

Abstract: A fuel injection control method includes measuring EGR (exhaust gas recirculation) rate through a CO2 sensor measuring the amount of CO2 entering the intake side of the engine, setting an optimum SCR (Steam to Carbon Ratio) value based on the measured EGR rate, calculating the amount of steam supplied to the engine based on the measured EGR rate, calculating an actual SCR value by the ratio of the steam amount and the carbon component of the fuel supplied to the engine, comparing the actual SCR value with the optimum SCR value, calculating the SCR difference value by subtracting the optimum SCR value from the actual SCR value if the actual SCR value is greater than the optimum SCR value, calculating an additional fuel amount to be added based on the SCR difference value, and injecting fuel to the fuel reformer based on the calculated additional fuel amount.

Abstract: A data acquisition system (DAS) includes a plurality of processors comprising at least one first processor and a plurality of second processors. The at least one first processor is configured to receive at least one configuration file and generate at least one measurement data application from the at least one configuration file. The DAS also includes a field-programmable gate array (FPGA) coupled to the plurality of processors. The FPGA is configured to receive the at least one measurement data application and allocate at least a portion of one of the FPGA and at least one second processor of the plurality of second processors to calculate measurement data at least partially based on the at least one measurement data application and an availability of the at least a portion of the FPGA.

Abstract: In a method for dynamic monitoring of gas sensors of an internal combustion engine, in the event of a change of the gas state variable to be measured, a dynamic diagnosis is carried out based on a comparison of a measured signal which is an actual value of an output signal of the gas sensor and a modeled signal which is a model value. The output signal of the gas sensor is filtered using a high-pass filter and higher-frequency signal components are analyzed.

Abstract: A control apparatus of an internal combustion engine having an injector which directly injects fuel into a combustion chamber of a cylinder and a spark plug which ignites an air-fuel mixture containing the fuel injected by the injector includes an air-fuel ratio acquisition unit acquiring an air-fuel ratio of the air-fuel mixture in the combustion chamber, a nitrogen oxide concentration acquisition unit acquiring a concentration of nitrogen oxide in a combustion gas exhausted from the internal combustion engine, and a stratification level estimation unit estimating a level of stratification as a measure of level of distribution of the air-fuel mixture at a predetermined air-fuel ratio or below in a vicinity of the spark plug. The stratification level estimation unit estimates the level of stratification according to the air-fuel ratio acquired by the air-fuel ratio acquisition unit and the concentration of nitrogen oxide acquired by the nitrogen oxide concentration acquisition unit.

Abstract: A system and method of detecting fueling imbalance(s) in an internal combustion engine is provided. The method includes receiving data regarding an oxygen content of engine exhaust for the engine operating at a cycle rate. Frequency component analysis is performed comprising a filtering operation on the received oxygen content data. The filtering is done at the cycle rate of the engine or harmonics thereof to obtain filtered oxygen content data. Then, the method/system determines at least one of: 1) one or more angles of the engine at which the filtered oxygen content data exhibits a first amplitude value characteristic relative to amplitude values at other angles; and 2) a shape of the filtered oxygen content data obtained by sampling at pre-defined engine angles. The method/system then identifies a cylinder experiencing a fueling imbalance responsive to the determined at least one of one or more angle(s) and shape of the data.

Abstract: A method for operating an internal combustion engine having a plurality of cylinders includes: measuring, by exhaust gas sensors arranged at an exhaust gas of every cylinder for which cylinder-specific combustion control is carried out, for each respective cylinder, at least one actual combustion value; comparing each respective measured actual combustion value with a reference combustion value to determine at least one cylinder-specific control deviation for every cylinder for which cylinder-specific combustion control is carried out; determining at least one cylinder-specific control variable for every cylinder for which cylinder-specific combustion control is carried out based on the cylinder-specific control deviation or on every cylinder-specific control deviation; and operating each cylinder for which cylinder-specific combustion control is carried out based on the respective cylinder-specific control variable to bring the respective actual combustion value closer to the respective reference combustion

Abstract: A method for ascertaining the absolute fuel injection quantity of the injectors of an internal combustion engine including a cylinder number, the average absolute total injection quantity of the injectors being ascertained based on a run-up test in which all cylinders of the engine are active, recorded measurement data, and a predetermined engine-specific factor which is proportional to the moment of inertia of the engine when all cylinders are active, and the measurement data being essentially suited for describing the chronological progression of the engine speed during the run-up test, in particular a reached maximum engine speed, a first rate of change of the engine speed during the run-up with active injection, a second rate of change of the engine speed with inactive injection, and an idling speed of the engine.

Abstract: A mobile device comprises a CPU operating a display and other user interface circuitry. Further, it comprises a gas sensor as well as a sensor hub connecting the gas sensor and other sensors to the CPU. In order to save power, the device can be brought into a low-power operating mode, where the CPU is idling or switched-off and the gas sensor itself has a low-power and a high-power operating mode. However, even in this low-power operating mode, the sensor hub still monitors for changes of the signal from the gas sensor and wakes the device up if such a change is detected.

Abstract: A method for the fuel consumption reduction and/or power increase of an internal combustion engine of a motor vehicle is disclosed. A crank angle of a crankshaft is detected at which out of a cylinder the exhaust gases of a cylinder can be representatively measured on a lambda probe. The exhaust gas flow is measured on the lambda probe. A signal of the lambda probe is scanned at the time of the detection of the crank angle. A value indicated the detected angle and/or the scanned signal is sent to a computer. The value is corrected with the help of an exhaust gas pressure or exhaust gas back pressure model stored in the computer. An effective combustion lambda of the cylinder is calculated based on the sent values and a global lambda value stored in the computer and used to the control of the internal combustion engine.

Abstract: Methods and systems are provided for detecting an air-fuel imbalance based on output from multiple degradation monitors. In one example, a method comprises, during feedback engine air-fuel ratio control responsive to output of an exhaust gas sensor positioned downstream of a catalyst, indicating a cylinder imbalance responsive to a catalyst transfer function determined only within a specified frequency range based on the exhaust gas sensor output after determining that the catalyst is nominal, and adjusting an actuator in response to the indicated cylinder imbalance. In this way, air-fuel ratio imbalances may be accurately identified and mitigated, thereby reducing emissions.

Abstract: An air-fuel-ratio of each cylinder is estimated based on a detection value of an air-fuel-ratio sensor. An air-fuel-ratio detection timing determination is executed to determine whether a deviation in air-fuel-ratio detection timing exists based on the estimated air-fuel-ratio while the cylinder-by-cylinder air-fuel-ratio control is performed. An observation residual is computed based on the detection value of the air-fuel-ratio sensor and the estimated air-fuel-ratio. When the observation residual is greater than or equal to a specified threshold value, the air-fuel-ratio detection timing determination is prohibited. Therefore, when the observation residual is still large before the estimated air-fuel-ratio of each cylinder is converged, or when the observation residual is still large due to a temporal deterioration in estimating accuracy of the estimated air-fuel-ratio, the air-fuel-ratio detection timing determination can be prohibited.

Abstract: Air/fuel imbalance monitoring systems and methods for monitoring air/fuel ratio imbalance of an internal combustion engine are disclosed. In one embodiment, adjusting engine operation responsive to cylinder air/fuel imbalance based on a determined total number of instances where sensed peak-to-peak exhaust air-fuel ratios differentials are less than a threshold normalized to a total number of peak-to-peak oscillations. The approach can be used to indicate air/fuel ratio imbalances between engine cylinders.

Abstract: A method of controlling an engine to help achieve a target air:fuel ratio based on data from an oxygen sensor, and related systems. At least one engine operating parameter and a sensed oxygen level are determined at two or more points in one of a rich and lean region based on data from the oxygen sensor. This information is used to help control engine operation in the other of the rich and lean regions without using directly sensed oxygen level data from that region. Thus, a control paradigm is developed in a first operating region based on oxygen level data from the oxygen sensor, and then used for control in a different second operating region without direct sensed oxygen level data in that second operating region. In some embodiments, the control paradigm may be adaptive based on changing conditions.

Abstract: An internal combustion engine has a plurality of cylinders with fuel-metering injection valves, and an exhaust gas probe that generates a measurement signal characteristic of the air/fuel ratio in the respective cylinder. A correction signal for fuel mass to be metered is determined using a lambda controller as a function of the exhaust gas probe measurement signal. When at least one predefined condition is met within a predefined operating range of the engine, a cylinder-specific diagnosis relating to the emissions of pollutants is performed on the basis of unsmooth running, wherein the cylinder-specific diagnosis is actively performed only in a respective detection phase that is applied to a neutral value by a modified proportional discrete level of the correction signal and is performed with a modified integral parameter of the lambda controller that is reduced as compared with an integral parameter in a normal operating mode of the lambda controller.

Abstract: Methods and systems are provided for converting an asymmetric degradation response of an exhaust gas sensor to a more symmetric degradation response. In one example, a method includes adjusting fuel injection responsive to a modified exhaust oxygen feedback signal from an exhaust gas sensor, the modified exhaust oxygen feedback signal modified by transforming an asymmetric response of the exhaust gas sensor to a more symmetric response. Further, the method may include adjusting one or more parameters of an anticipatory controller of the exhaust gas sensor based on the modified symmetric response.

Abstract: A control device (10) for controlling an operating device (100), comprising an evaluation unit (20), a first position sensor unit (30a) for determining the position of a first component (130a) of the operating device (100) and a second position sensor unit (30b) for determining the position of a second component (130b) of the operating device (100). The evaluation unit (20) is connected to the position sensor units (30a, 30b) to permit signal communications and is constructed as a common evaluation unit (20) for evaluating the signals of the position sensor units (30a, 30b).

Abstract: A fuel injection amount control system corrects the amount of fuel injected from each fuel injection valve in a feedback manner, based on an output value of an upstream air-fuel ratio sensor, so that the air-fuel ratio of exhaust gas flowing into a three-way catalyst coincides with a target air-fuel ratio. Also, the control system performs a high-pass filtering operation on the output value of the upstream air-fuel ratio sensor, so as to obtain a post-high-pass-filtering output value by removing a component that varies with variations in the center air-fuel ratio of the engine, from the output value of the upstream air-fuel ratio sensor. Then, the control system acquires an air-fuel ratio imbalance index value that increases as the degree of ununiformity in the air-fuel ratio among cylinders is larger, based on the post-high-pass-filtering output value.

Abstract: An air-fuel ratio imbalance detecting device for an internal combustion engine, which detects a rich imbalance in air-fuel ratio among a plurality of cylinders on the basis of a variation per unit time in air-fuel ratio that is detected by an air-fuel ratio sensor provided in an exhaust passage of the internal combustion engine, includes an electronic control unit that normalizes the variation per unit time in air-fuel ratio with a constant associated with a rotation speed and load factor of the internal combustion engine and that, when the normalized value is smaller than a predetermined threshold, determines that a rich imbalance in air-fuel ratio has been detected among the cylinders.

Abstract: A control apparatus for an internal combustion engine including a plurality of combustion chambers and a catalyst that cleans exhaust gases includes a controller configured to execute individual air-fuel ratio control in which an air-fuel ratio of an air-fuel mixture generated in at least one non-specific combustion chamber is controlled such that an average air-fuel ratio of the engine matches a target air-fuel ratio, based on an air-fuel ratio of an air-fuel mixture generated in at least one specific combustion chamber, the controller being configured to execute catalyst temperature increase control in which a temperature of the catalyst is increased, and the controller being configured to prohibit execution of the individual air-fuel ratio control when the catalyst temperature increase control is executed.

Abstract: The present invention intends to perform control for detecting a change in air-fuel ratio with high accuracy by an exhaust gas sensor in an internal combustion engine having a turbocharger with a wastegate valve. A control apparatus for an internal combustion engine according to the present invention includes: a turbocharger; a wastegate through which an exhaust gas passes while bypassing a turbine; a wastegate valve for opening/closing the wastegate; an exhaust gas sensor provided in an exhaust passage on the downstream side from the turbine and the wastegate valve; and air-fuel ratio change detection controlling means for executing air-fuel ratio change detection control to change an air-fuel ratio on the upstream side from the turbine and the wastegate valve and detect a change in the air-fuel ratio by the exhaust gas sensor.

Abstract: An apparatus for detecting an abnormal air-fuel ratio variation among cylinders of a multi-cylinder internal combustion engine includes: a detecting unit detecting the abnormal air-fuel ratio variation on the basis of output fluctuations of at least one predetermined target cylinder when fuel injection amount changing control for changing a fuel injection amount of the target cylinder by a predetermined amount is executed; and an air-fuel ratio control unit causing an air-fuel ratio detected on the basis of a signal output from an air-fuel ratio sensor provided in an exhaust passage to follow a predetermined target air-fuel ratio. When the fuel injection amount changing control is executed, a target air-fuel ratio in the air-fuel ratio feedback control is shifted from the predetermined target air-fuel ratio by an amount corresponding to an amount of change of the fuel injection amount of the target cylinder in the fuel injection amount changing control.

Abstract: An ECU executes a cylinder-by-cylinder air-fuel-ratio control in which an air-fuel-ratio of each cylinder is estimated based on a detection value of an air-fuel-ratio sensor to adjust the air-fuel-ratio of each cylinder. Further, the ECU computes a learning value of a correction quantity for each cylinder, which is obtained by executing the cylinder-by-cylinder air-fuel-ratio control. Then, the ECU determines whether the estimated air-fuel-ratio has converged according to whether the estimated air-fuel-ratio of each cylinder has been closer to a target value than a specified value for not less than a specified time period. A computation of the learning value is prohibited until the estimated air-fuel-ratio has converged. Therefore, it can be avoided to compute the learning value based on the fuel correction quantity that is obtained when the estimated air-fuel-ratio has not converged yet.

Abstract: An apparatus for controlling an air-fuel ratio of an internal-combustion engine includes an air-fuel ratio detector, a fluctuation signal generating device, an air-fuel ratio fluctuation device, a 0.5th-order frequency component strength calculator, a fluctuation frequency component strength calculator, a reference component strength calculator, and an imbalance fault determining device. The reference component strength calculator is configured to calculate strength of a reference component in accordance with strength of a first frequency component and strength of a second frequency component. The imbalance fault determining device is configured to make a determination of an imbalance fault in which air-fuel ratios of a plurality of cylinders vary beyond a tolerance limit on a basis of a relative relationship between strength of the 0.5th-order frequency component and the strength of the reference component.

Abstract: An air-fuel-ratio of each cylinder is estimated based on a detection value of an air-fuel-ratio sensor. An air-fuel-ratio detection timing determination is executed to determine whether a deviation in air-fuel-ratio detection timing exists based on the estimated air-fuel-ratio while the cylinder-by-cylinder air-fuel-ratio control is performed. An observation residual is computed based on the detection value of the air-fuel-ratio sensor and the estimated air-fuel-ratio. When the observation residual is greater than or equal to a specified threshold value, the air-fuel-ratio detection timing determination is prohibited. Therefore, when the observation residual is still large before the estimated air-fuel-ratio of each cylinder is converged, or when the observation residual is still large due to a temporal deterioration in estimating accuracy of the estimated air-fuel-ratio, the air-fuel-ratio detection timing determination can be prohibited.

Abstract: Systems and methods for determining operation of a cylinder deactivating/reactivating device are disclosed. In one example, degradation of the cylinder deactivating/reactivating device is based on intake manifold oxygen concentration.

Abstract: A judging device comprises a catalyst, an upstream air/fuel ratio sensor having an air/fuel ratio sensing element covered with a diffusion resistance layer, and a downstream air/fuel ratio sensor. The judging device performs main feedback control to equalize the air/fuel ratio indicated by the output value of the upstream air/fuel ratio sensor to an upstream target air/fuel ratio and sub-feedback control to equalize the output value of the downstream air/fuel ratio sensor to a downstream target value. The judging device acquires “an imbalance judging parameter” which increases with “the increase of the difference between the amount of hydrogen contained in the exhaust gas before the exhaust gas passes through the catalyst and that after the exhaust gas passes through the catalyst” according to the sub-feedback amount. When the imbalance judging parameter is larger than an abnormality judgment threshold, the judging device judges that an air/fuel ratio imbalance among the cylinders has occurred.

Abstract: An internal combustion engine has a plurality of cylinders with fuel-metering injection valves, and an exhaust gas probe that generates a measurement signal characteristic of the air/fuel ratio in the respective cylinder. A correction signal for fuel mass to be metered is determined using a lambda controller as a function of the exhaust gas probe measurement signal. When at least one predefined condition is met within a predefined operating range of the engine, a cylinder-specific diagnosis relating to the emissions of pollutants is performed on the basis of unsmooth running, wherein the cylinder-specific diagnosis is actively performed only in a respective detection phase that is applied to a neutral value by a modified proportional discrete level of the correction signal and is performed with a modified integral parameter of the lambda controller that is reduced as compared with an integral parameter in a normal operating mode of the lambda controller.

Abstract: An apparatus for detecting abnormal air-fuel ratio variation among cylinders of a multi-cylinder internal combustion engine includes: a catalyst element that oxidizes hydrogen contained in exhaust gas to remove the hydrogen; a first air-fuel ratio sensor that detects an air-fuel ratio of exhaust gas that has not passed through the catalyst element; a second air-fuel ratio sensor that detects an air-fuel ratio of exhaust gas that has passed through the catalyst element; and a unit that determines whether abnormal air-fuel ratio variation among the cylinders has occurred based on an amount by which a value detected by the second air-fuel ratio sensor is leaner than a value detected by the first air-fuel ratio sensor.

Abstract: An apparatus for determining an air-fuel ratio imbalance among cylinders based on an output value of an air-fuel ratio sensor, an imbalance determination parameter which becomes larger or smaller as a difference among air-fuel ratios becomes larger, and performs determining an air-fuel ratio imbalance among cylinders based on a result of a comparison between the imbalance determination parameter and a imbalance determination threshold. The determining apparatus calculates a purge correction coefficient which compensates for a change in the air-fuel ratio due to an evaporated fuel gas which is generated in a fuel tank, while the evaporated fuel gas is being introduced into an intake passage, and corrects a fuel injection amount with the purge correction coefficient FPG.

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

Abstract: An inter-cylinder air-fuel ratio imbalance abnormality determination device includes a catalyst provided in an exhaust passage of a multi-cylinder internal combustion engine; a pre-catalyst sensor; a post-catalyst sensor; an air-fuel ratio control unit that performs main air-fuel ratio control based on an output of the pre-catalyst sensor and auxiliary air-fuel ratio control based on an output of the post-catalyst sensor; a control amount calculation unit that calculates a control amount in the auxiliary air-fuel ratio control based on the output of the post-catalyst sensor; a revolution speed variation detection unit that detects a revolution speed variation of the engine; an abnormality determination unit that performs imbalance abnormality determination for determining whether an inter-cylinder air-fuel ratio imbalance abnormality has occurred based on a detected value of the revolution speed variation; and a guard range reduction unit that reduces a guard range of the control amount during the imbalance a

Abstract: An inter-cylinder air-fuel-ratio imbalance determination apparatus includes an air-fuel-ratio sensor in an exhaust passage of an engine. The air-fuel-ratio sensor functions as a limiting-current-type wide range air-fuel-ratio sensor when a voltage is applied, and functions as a concentration-cell-type oxygen concentration sensor when no voltage is applied. The determination apparatus causes the air-fuel-ratio sensor to function as the limiting-current-type wide range air-fuel-ratio sensor, and executes air-fuel ratio feedback control on the basis of the output value of the air-fuel-ratio sensor. When an imbalance determination parameter is obtained, the determination apparatus causes the air-fuel-ratio sensor to function as the concentration-cell-type oxygen concentration sensor, and obtains, as the imbalance determination parameter, a value corresponding to the differentiated value of the output value of the air-fuel-ratio sensor.

Abstract: In view of a difference in detectability of an air-fuel ratio sensor with respect to each cylinder, a first exhaust system model and a second exhaust system model are defined. The first exhaust system model outputs an air-fuel ratio at the confluent portion based on an air-fuel ratio in a cylinder. The second exhaust system model outputs a detection value of the exhaust gas sensor based on the air-fuel ratio at the confluent portion. A confluent-portion-air-fuel ratio estimating portion designed based on the second exhaust system model estimates the air-fuel ratio at the confluent portion. A combust-air-fuel ratio estimating portion designed based on the first exhaust system model estimates a combust-air-fuel ratio in each cylinder.

Abstract: The invention relates to an air-fuel ratio control device of an internal combustion engine, comprising a plurality of means for independently introducing into each combustion chamber an exhaust gas discharged from combustion chambers to an exhaust passage. When at least one exhaust gas introduction means is under an exhaust gas introduction shortage state, a target value of an air-fuel ratio of a mixture gas is changed depending on whether an exhaust gas introduction control for introducing the exhaust gas into the combustion chamber by the exhaust gas introduction means is performed.

Abstract: An abnormality detection apparatus for a multi-cylinder internal combustion engine changes a fuel injection quantity of a predetermined target cylinder to detect an abnormality of an internal combustion engine based on values of rotational variations relating to the target cylinder detected before and after the change of the fuel injection quantity. The abnormality detection apparatus corrects the values of the rotational variations relating to the target cylinder detected before and after the change of the fuel injection quantity based on at least one of the number of revolutions of the engine and an engine load at a corresponding detection time.

Abstract: In a method for operating an internal combustion engine, a computer program product, a computer program, and a control and/or regulation device for the internal combustion engine, the internal combustion engine is allowed to be operated using an enriched air/fuel mixture, without exceeding a rich combustion limit of the internal combustion engine. In the process, a setpoint value for a variable characterizing the air/fuel mixture is specified in at least one operating state of the internal combustion engine. A value of at least one variable characterizing the quality of combustion is determined. The determined value for the at least one variable characterizing the quality of combustion is compared to a first specified threshold value. If the determined value for the at least one variable characterizing the quality of combustion deviates from the first specified threshold value by an amount that exceeds a second specified threshold value, then the setpoint value is corrected.

Abstract: An engine control apparatus having a unit for calculating the mean value of the angular acceleration with respect to each cylinder; a unit for calculating the variance of the angular acceleration with respect to each cylinder; a unit for estimating the torque and the air/fuel ratio with respect to each cylinder on the basis of the mean value and the variance; and a unit for controlling at least one of the intake air amount, the fuel injection amount and the ignition timing with respect to each cylinder on the basis of the estimated torque and air/fuel ratio.

Abstract: A method for controlling combustion in a multi-cylinder engine includes injecting fuel into at least one cylinder of the multi-cylinder engine and, for each cylinder, separately controlling at least one fuel injection parameter to produce a desired exhaust composition for that cylinder. A multi-cylinder engine is also disclosed.

Abstract: A control device is applied to an internal combustion engine capable of using CNG and gasoline by switching therebetween, and the CNG and the gasoline are associated, as fuel for use, with one and the other of two driving areas respectively, the driving areas being different from each other. The control device exceptionally switches the fuel for use from gasoline to CNG and implements an air-fuel ratio imbalance inspection (S6, S7), when the air-fuel ratio imbalance inspection is required for a CNG mode using CNG (S1), the engine is driving in a driving area (AR2) correlated to gasoline as fuel for use (S2), and gasoline mode using gasoline as fuel for use is ongoing (S3).

Abstract: A control apparatus for an internal combustion engine includes: a first detector that detects air/fuel ratio in an exhaust passageway on an upstream of an exhaust gas-controlling catalyst in multi-cylinder internal combustion engine; a second detector that detects the air/fuel ratio in the exhaust passageway on a downstream of the catalyst; a feedback controller that executes a feedback control so that a first detected value based on the first detector output follows to be equal as a first predetermined target value and so that a second detected value based on the second detector output follows to be equal as a second predetermined target value that corresponds to the first predetermined target value during an initial state; an abnormality detection device configured to detect a variation abnormality in the air/fuel ratio among the cylinders; and a change device that changes the second predetermined target value when the variation abnormality is detected.

Abstract: Provided is an internal combustion engine system controller, including a sub-feedback learning section, a state determining section, and a learning update-speed setting section. The state determining section determines, to which of at least three states including: (a) a stable state in which a fluctuating state of a sub-feedback learning value is stable; (b) an unstable state in which the fluctuating state greatly fluctuates; and (c) an intermediate state between the stable state and the instable state (may be referred to as sub-stable state), the fluctuating state corresponds. The learning update-speed setting section sets an update speed of the sub-feedback learning value in accordance with the result of determination by the state determining section. Further, the learning update-speed setting section suppresses the occurrence of hunting of the sub-feedback learning value.

Abstract: A control system and method of controlling operation of an internal combustion engine includes a load determination module that determines an engine load, an equivalence ratio module that determines an equivalence ratio, a correction factor module that generates a correction factor based on the engine load, the equivalence ratio, and the engine speed and an engine operation module that regulates operation of the engine based on the correction factor.

Abstract: A cylinder-to-cylinder air/fuel ratio imbalance determination system obtains an imbalance determination parameter that increases or decreases as a difference between the air/fuel ratios of different cylinders increases, based on output values of an air/fuel ratio sensor, and makes a cylinder-to-cylinder A/F imbalance determination, based on the result of comparison between the imbalance determination parameter and a threshold value for imbalance determination. The determination system changes the amount of fuel injected into one or more of the cylinders so as to create a forced imbalance condition in which the air/fuel ratio of a particular cylinder deviates from the air/fuel ratio of the remaining cylinders, and obtains an air/fuel ratio sensor evaluation parameter (e.g., rate of change ?AF of the detected air/fuel ratio) in this condition.

Abstract: A control system for an internal combustion engine, wherein in the control system, an in-cylinder oxygen amount is calculated and a compression end temperature, which is a temperature of the pressurized air-fuel mixture, is calculated according to an intake air temperature. A fuel injection parameter is determined according to the compression end temperature, the in-cylinder oxygen amount, and an engine rotational speed. The fuel injector is controlled based on the determined fuel injection parameter. By determining the fuel injection parameter according to the compression end temperature in addition to the in-cylinder oxygen amount, the combustion state is adjusted when the compression end temperature is low, thereby maintaining a stable combustion state.