Abstract: A hybrid vehicle includes: a multi-cylinder internal combustion engine and an electric motor, a power source control unit that controls the engine and the motor, an air-fuel ratio control unit that controls the air-fuel ratio of exhaust gas of the engine to obtain a target air-fuel ratio, a battery that stores electric power that is supplied to the motor, a state-of-charge detection unit that detects a state-of-charge of the battery, a detection unit that detects an air-fuel ratio imbalance abnormality of the internal combustion engine and identifies an abnormal cylinder that has caused the imbalance abnormality, and a correction unit that corrects, in a case where the air-fuel ratio imbalance abnormality has been detected, a fuel injection amount of the abnormal cylinder based on a battery state-of-charge decrease amount from when the abnormality is detected to the time when a predetermined time interval is elapsed after the detection.

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: An engine system includes a first module that determines a cylinder of an engine to be in one of M prediction types and generates a distance from intake signal indicating a number of prediction steps the cylinder is away from an intake stroke. M is an integer greater than or equal to 3. A second module determines a cycle type of the cylinder. The cycle type indicates a number of combustion cycles the cylinder has experienced from a last restart of the engine. A cylinder air charge module estimates an air mass within the cylinder based on the distance from intake signal and the cycle type.

Abstract: An oscillation signal is generated to oscillate the air-fuel ratio with a set frequency which is different from a 0.5th-order frequency (half of the frequency corresponding to a rotational speed of the engine). Air-fuel ratio perturbation control is performed to oscillate the air-fuel ratio according to the oscillation signal. An intensity of the 0.5th-order frequency component and the set frequency component contained in the detected air-fuel ratio signal are calculated. A determination parameter applied to determining an imbalance degree of air-fuel ratios corresponding to the plurality of cylinders is calculated according to the two intensities and determines an imbalance failure that the imbalance degree of the air-fuel ratios exceeds an acceptable limit. A predicted imbalance value, indicative of a predicted value of the imbalance degree, is calculated, and an amplitude of the oscillation signal is set according to the predicted imbalance value.

Abstract: An air-fuel ratio imbalance determining apparatus that is configured to sequentially stop a fuel injection for each of cylinders in accordance with a firing (ignition) order by changing the intake valves and exhaust valves of the cylinder whose fuel injection is stopped from a valve operating state to a valve resting state. After a predetermined time elapses (time-point tp), an upstream-side air-fuel ratio value obtained based on an output value of an upstream air-fuel ratio sensor disposed in the exhaust passage which becomes a value corresponding to an air-fuel ratio of the final gas. The determining apparatus obtains that value as data relating to an air-fuel ratio of the cylinder which discharged the final gas, and determines whether or not an air-fuel ratio imbalance is occurring based on the data relating to the air-fuel ratio of each of the cylinders.

Abstract: An internal combustion engine wherein three-way catalysts are arranged in an exhaust passage of a first cylinder group and an exhaust passage of a second cylinder group and a common NOx storage catalyst is arranged downstream of the three-way catalysts. When the NOx storage catalyst should be raised in temperature, the air-fuel ratio of a part of the cylinders in each cylinder group is made rich and the air-fuel ratio of a part of the cylinders in each cylinder group is made lean to raise the NOx storage catalyst in temperature by the heat of oxidation reaction at the three-way catalysts.

Abstract: An inter-cylinder air/fuel ratio imbalance abnormality detection apparatus for a multicylinder internal combustion engine includes a fuel injection amount change control portion that executes a fuel injection amount change control of forcing a fuel injection amount of a predetermined object cylinder to change by a predetermined amount; an ignition timing retardation control portion that executes an ignition timing retardation control for the predetermined object cylinder; and a detection portion that detects an inter-cylinder air/fuel ratio imbalance abnormality based on output fluctuation regarding the predetermined object cylinder occurring when the fuel injection amount change control and the ignition timing retardation control are executed together for the predetermined object cylinder.

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: A system includes an offset determination module and a correction determination module. The offset determination module determines an offset value based on an average response time of an exhaust gas oxygen (EGO) sensor located upstream of a catalyst in an exhaust system. The offset value relates one of a predetermined number of cylinder imbalance values to a cylinder of an engine. The correction determination module determines a fueling correction for the cylinder based on the offset value and one of the predetermined number of cylinder imbalance values.

Abstract: Upon satisfaction of the condition for making the malfunction diagnosis at least one of the EGR system, the air-fuel ratio sensor and the oxygen sensor during the fuel cut of the engine, a fuel cut of the engine and performing the mortaring of the engine by means of the motor MG1 are continued until the completion of the malfunction diagnoses of all objects, of which the each condition for making the malfunction diagnosis is satisfied among the EGR system, the air-fuel ratio sensor and the oxygen sensor. This arrangement ensures the occasions for making the malfunction diagnoses of the EGR system, the air-fuel ratio sensor and the oxygen sensor.

Abstract: The invention relates to the field of methods and devices for reducing the difference between normalized air-fuel ratio of the various cylinders compared with a predetermined value between 0.7 and 1.1, of the normalized air-fuel ratio in an internal combustion engine. The method and devices utilize the signal of the ionization current produced by a suitable device, modifying the quantity of fuel on the basis of the signal determined by means of the method in question in the invention.

Abstract: Methods and devices for controlling the normalized air-fuel ratio of an internal combustion engine, otherwise known, in technical terms, as Lambda. The present invention is based on the use of the ionization current released by a device positioned on each cylinder of the engine. This ionization current is measured by a Control Unit equipped with a low-pass filter and electronic means which implement the invention.

Abstract: A system includes an offset determination module and a correction determination module. The offset determination module determines an offset value based on an average response time of an exhaust gas oxygen (EGO) sensor located upstream of a catalyst in an exhaust system. The offset value relates one of a predetermined number of cylinder imbalance values to a cylinder of an engine. The correction determination module determines a fueling correction for the cylinder based on the offset value and one of the predetermined number of cylinder imbalance values.

Abstract: In an internal combustion engine, at least one rotation variable characterizing the rotational movement of a crankshaft is ascertained cylinder-specifically. It is provided that, in an operating state in which differences and/or fluctuations of the rotation variable are basically a function of a combustion position, the instant of a fuel injection is adapted cylinder-specifically in order to reduce the differences and or fluctuations.

Abstract: A control system for diagnosing a fuel system of a vehicle is provided. The system generally includes a correction term module that estimates a fuel correction term based on a first fuel correction value and a second fuel correction value, wherein the first fuel correction value is based on a first period and the second fuel correction value is based on a second period, and wherein the first period is longer than the second period. A diagnostic module diagnoses the fuel system of the vehicle based on the fuel correction term.

Abstract: A computer-implemented function monitors and displays exhaust gas temperatures (EGT) in a plurality of cylinders in an engine. The invention provides an easy way to read exhaust gas temperature on a specific cylinder, and to provide a means for leaning the engine while in a climb. Efficient leaning in a climb reduces fuel consumption and reduces the chance of harmful conditions that can lead to engine failure.

Abstract: With an internal combustion engine (1) there is the problem that the fuel-air mixture directed into the combustion chamber of the cylinders (2) can be substantially influenced by manufacturing tolerances and ageing of the fuel injectors and uneven distribution is thus created. The uneven distribution is individually determined for each cylinder (2) depending on the operating mode of the internal combustion engine (1) (homogenous operation, stratified operation), wherein either the exhaust gas is analyzed and a corresponding emission value is determined therefrom or that a value is individually determined for each cylinder (2) for the operational roughness of the internal combustion engine (1). These values are compared with a limit value predetermined for the internal combustion engine (1) and upon exceeding of the predetermined limit value a fault entry in a fault memory (9) is made for the cylinder (2) concerned.

Abstract: A system and method are disclosed for controlling an internal combustion engine in which actual concentration of combusted gas in the intake is compared with desired concentration of combusted gas in the intake. When a difference is detected, at least one of start of injection timing and quantity of fuel injected is adjusted in accordance with the difference. The actual concentration of combusted gas in the intake is estimated based on engine sensors such as an oxygen sensor coupled to an engine intake. The adjustment of injection timing and/or quantity of fuel is performed, according to some embodiments, during a transition between a low temperature combustion mode and a standard diesel combustion mode.

Abstract: A control system for a gas engine including a controller being configured to execute load equalization control such that a fuel feed amount corresponding to a higher-temperature cylinder of a first predetermined number which is selected to include a highest exhaust gas temperature, among cylinders which are controlled targets, is reduced, and a fuel feed amount corresponding to a lower-temperature cylinder of a second predetermined number which is selected to include a lowest exhaust gas temperature, among the cylinders which are the controlled targets, is increased; and a sum of the first predetermined number and the second predetermined number being less than the number of all of the plurality of cylinders so that there is a cylinder whose fuel feed amount is not changed.

Abstract: To determine the gas work WK from the areas formed by the cylinder pressure curve over the associated stroke volume V?, a cylinder-pressure-proportional integrator is started integrating the signals of the cylinder pressure sensor in multiple integrator runs depending on a settable integrator capacitance. A lower and an upper threshold value are predefined, whose difference corresponds to the integrator capacitance. Upon reaching one of the threshold values, respective new integrator runs are started, at the beginning and end of which the current crankshaft angle ? (is detected, respectively. For each integrator run, the associated individual work is determined depending on the product of the integrator capacitance and the particular covered stroke volume and the gas work resulting from the cylinder pressure curve is determined by summation of the individual works. The gas work may be used in particular for determining the internal mean pressure of the cylinder.

Abstract: In an internal combustion engine, gasoline is injected directly into a combustion chamber and ignited by auto-ignition. The characteristics map range within which fuel is ignited by auto-ignition is enlarged by supercharging the internal combustion engine.

Abstract: A control system for an internal combustion engine, which is capable of properly setting fuel injection timing according to the actual degree of delay of the amount of fresh air to be supplied to cylinders of the engine, thereby making it possible to positively suppress torque variation, when the control system has switched an air-fuel ratio mode between a lean mode and a rich mode. The control system controls the air-fuel ratio of a mixture by switching the air-fuel ratio mode. In the lean mode, the control system sets a target fresh air amount for the lean mode, and in the rich mode, it sets a target fresh air amount for the rich mode. Upon switching the air-fuel ratio mode, the control system corrects the fuel injection timing according to the difference between the target fresh air amount for the lean mode or the rich mode and the detected fresh air amount.

Abstract: A fuel injection device includes a fuel injection valve for injecting fuel, which is distributed from a pressure-accumulation vessel. A pressure sensor is located in a fuel passage, which extends from the pressure-accumulation vessel to a nozzle hole, and configured to detect pressure of the fuel. The pressure sensor is located closer to the nozzle hole than the pressure-accumulation vessel. A storage unit stores individual difference information, which indicates an injection characteristic of the fuel injection valve, the injection characteristic being obtained by an examination. The individual difference information is related to a fluctuation pattern of a portion of the fluctuation in detected pressure waveform of the pressure sensor. The fluctuation is attributed to one fuel injection through the nozzle hole. The portion of the fluctuation is subsequent to an end of the fuel injection.

Abstract: An engine control system includes an fuel injector for each cylinder of the engine, an air-fuel ratio sensor disposed in an exhaust manifold and an electronic control unit to which signals from various sensors are fed. Operation of the engine is controlled by the electronic control unit. An air-fuel ratio deviation among cylinders is calculated based on output signals of the air-fuel ratio sensor, and injection amount errors of each injector are calculated from the deviation of air-fuel ratio among cylinders. An injection characteristic of each injector is learned from the injection amount errors, and a right amount of fuel is supplied to each cylinder based on the learned injection characteristic. In this manner, the injection amount errors are effectively adjusted, and the air-fuel ratio deviation among cylinders due to external disturbances is surely adjusted.

Abstract: An air/fuel ratio control system is provided for an internal combustion engine having a plurality of cylinders and an air/fuel ratio sensor. The air/fuel ratio sensor is disposed at an exhaust gas merging portion of an exhaust passage where exhaust gas discharged from the plurality of cylinders merges together. The system includes an air/fuel ratio control device, an abnormality diagnosis device, and an enabling device. The air/fuel ratio control device individually controls an air/fuel ratio of each of the plurality of cylinders based on an output of the air/fuel ratio sensor. The abnormality diagnosis device determines whether abnormality of the air/fuel ratio sensor exists. The enabling device enables the air/fuel ratio control device to execute the controlling of the air/fuel ratio of each of the plurality of cylinders when the abnormality diagnosis device determines that the abnormality of the air/fuel ratio sensor does not exist after starting of the engine.

Abstract: The invention relates to the field of methods and devices for reducing the difference between normalized air-fuel ratio of the various cylinders compared with a predetermined value between 0.7 and 1.1, of the normalized air-fuel ratio in an internal combustion engine. The method and devices utilize the signal of the ionization current produced by a suitable device, modifying the quantity of fuel on the basis of the signal determined by means of the method in question in the invention.

Abstract: An engine torque control module comprises a derivative module and a cylinder torque module. The derivative module determines a derivative term for a first cylinder of an internal combustion engine based on rotation of a crankshaft and determines an average derivative term for the first cylinder based upon the derivative term. The cylinder torque module determines an operating condition of the first cylinder based on the average derivative term, adjusts a torque output of the first cylinder based on the operating condition, and adjusts a torque output of a second cylinder based on the operating condition.

Abstract: A device for correcting the injection behavior of at least one injector includes an apparatus for storing information relating to the at least one injector and means for controlling the at least one injector. The device takes the stored information into account in the correction, the information having been ascertained by comparing setpoint values with actual values individually at a plurality of test points of the at least one injector, the information being activation times for an activation time correction map of the at least one injector.

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

Abstract: 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: When an internal combustion engine including a plurality of cylinders is operating steadily, an index value relating to an actual hydrogen content in exhaust gas downstream of a portion where exhaust passages from the cylinders merge, and upstream of a catalyst is detected. When an index value relating to the actual hydrogen content in the exhaust gas is larger than a determination index value relating to a hydrogen content corresponding to a permissible limit of air-fuel ratio variation, it is determined that there is abnormal air-fuel ratio variation between the cylinders.

Abstract: A cylinder causing an abnormal air-fuel ratio is specified. Injection ratio changing control for gradually changing a ratio between command injection quantities of two injectors of the abnormal cylinder while keeping the sum of the command injection quantities of the two injectors constant is performed on the abnormal cylinder. If the injection ratio changing control is performed under the same condition, a changing behavior of the actual sum injection quantity of the two injectors varies and a changing behavior of the air-fuel ratio varies depending on which one of the two injectors is abnormal. Therefore, the abnormal injector out of the two injectors is specified using a learning value of an air-fuel ratio feedback correction value based on an output of an exhaust gas sensor.

Abstract: An internal combustion engine comprising several cylinders provided with injection valves associated with the cylinders admeasuring fuel. An exhaust gas probe is arranged in an exhaust gas tract and the measuring signal thereof is characteristic for the air/fuel ratio in the respective cylinder. A sensing crankshaft angle is determined in relation to a reference position of the piston of the respective cylinder in order to detect the measuring signal according to a variable characterizing air/fuel ratio in the respective cylinder, or an ambient pressure or a degree of opinion of a bypass valve of a bypass associated with a turbine in which the exhaust gas tract is arranged. The measuring signal is detected at the sensing crankshaft angle and allocated to the respective cylinder.

Abstract: A fuel injection device calculates a variation correction value by incorporating in-cylinder pressure into injector individual data based on an injection rate of an injector measured outside a cylinder of an engine. The fuel injection device corrects a target injection amount and generation timing of a command signal of the injector based on the variation correction value. Thus, accurate injection characteristics substantially conforming to designed median values can be obtained inside the cylinder, and highly accurate injection control can be performed. Thus, the fuel injection device can perform accurate multi-injection, which requires extremely high accuracy, to simultaneously achieve reduction of engine vibration and engine noise, purification of exhaust gas and improvement of engine output and fuel consumption at high levels.

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

Abstract: In a lower partial load range of, a setpoint value of the mass flow of air into the combustion chambers is determined as a function of a predefined torque request such that it is greater than necessary for implementing the predefined torque request and large enough that individual exhaust packets can be differentiated from one another with the exhaust gas probe. Depending on the air/fuel ratio setpoint value, an actuator is actuated whose position affects the actual air mass flow. To implement the torque request, engine efficiency is simultaneously reduced by actuating another actuator. A measurement signal of the exhaust gas probe is detected. The air/fuel ratios of the exhaust packets are determined as a function of the measurement signal detected. At least one operating parameter affecting the air/fuel ratio in at least one of the cylinders is adapted as a function of the air/fuel ratios determined.

Abstract: An engine torque control system for balancing torque output across cylinders of an internal combustion engine includes a first module that determines a derivative term for each cylinder of the engine based on rotation of a crankshaft. A second module determines a torque correction for a first cylinder based on an average derivative term associated with the first cylinder. The second module adjusts a torque output of the first cylinder based on the torque correction and adjusts a torque output of a second cylinder based on the torque correction.

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: The present invention relates to a method of estimating the fuel/air ratio in each cylinder of an injection internal-combustion engine comprising an exhaust circuit on which a detector measures the fuel/air ratio of the exhaust gas. An estimator based on an adaptive nonlinear filter is coupled with a physical model representing the expulsion of the gases from the cylinders and their travel in the exhaust circuit to the detector. The estimator is also coupled with an estimation of the fuel/air ratio measured from at least one variable of said model such as the total mass of exhaust gas and the mass of fresh air. The method has application to engine controls.

Abstract: A method and system controls engine-out exhaust species of a combustion engine having a plurality of cylinders. The method typically includes various combinations of steps such as controlling combustion parameters in individual cylinders, grouping the individual cylinders into a lean set and a rich set of one or more cylinders, combusting the lean set in a lean combustion parameter condition having a lean air:fuel equivalence ratio, combusting the rich set in a rich combustion parameter condition having a rich air:fuel equivalence ratio, and adjusting the lean set and the rich set of one or more cylinders to generate net-lean combustion. The exhaust species may have elevated concentrations of hydrogen and oxygen.

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: A method of monitoring proper operation of an internal combustion engine by analyzing an engine speed includes the following steps: determination of an acceleration characteristic for each cylinder, which is a function of the engine acceleration between preferably directly successive working cycles of a specifiable number of examined cylinders; selection of the acceleration characteristics of one or a plurality of cylinders on the basis of specifiable criteria; and modification of an error characteristic provided for each examined cylinder as a function of the acceleration characteristic assigned to the cylinder, if an acceleration characteristic assigned to the cylinder has been selected.

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

Abstract: A control system for controlling a valve in a fuel system of engine including an engine airflow sensor that senses a mass engine airflow (Mengair), a barometric pressure sensor that senses a barometric pressure (Pbaro), and an ambient temperature sensor that senses an ambient temperature (Tamb). An actuator determination module determines an effective area (Aeff) of the valve based on at least one of the Mengair, the Pbaro, and the Tamb. A duty cycle (DC) calculation module that determines a first duty cycle (DC) of the valve based on the Aeff.

Abstract: An air/fuel ratio control system is provided for an internal combustion engine having a plurality of cylinders and an air/fuel ratio sensor. The air/fuel ratio sensor is disposed at an exhaust gas merging portion of an exhaust passage where exhaust gas discharged from the plurality of cylinders merges together. The system includes an air/fuel ratio control device, an abnormality diagnosis device, and an enabling device. The air/fuel ratio control device individually controls an air/fuel ratio of each of the plurality of cylinders based on an output of the air/fuel ratio sensor. The abnormality diagnosis device determines whether abnormality of the air/fuel ratio sensor exists. The enabling device enables the air/fuel ratio control device to execute the controlling of the air/fuel ratio of each of the plurality of cylinders when the abnormality diagnosis device determines that the abnormality of the air/fuel ratio sensor does not exist after starting of the engine.

Abstract: An individual-cylinder air-fuel ratio estimation model is designed so as to consider the mixing of gases exhausted from adjacent combustion cylinders, and a movement by which a mixed gas arrives at the position of an air-fuel ratio sensor, in order that influences ascribable to the intervals (combustion intervals) of the adjacent combustion cylinders may be reflected on the estimation values of individual-cylinder air-fuel ratios. In evaluating the mixing of the gases which are exhausted from the adjacent combustion cylinders, there are considered the lengths and shapes of the exhaust manifolds of the respective combustion cylinders. In evaluating the movement by which the mixed gas arrives at the position of the air-fuel ratio sensor, there are considered a distance or volume from the confluence to the position of the air-fuel ratio sensor, and the exhaust gas quantities of the respective combustion cylinders.

Abstract: A control apparatus calculates a exhaust gas air-fuel ratio of a plurality of cylinders, in which the operation angle of an intake valve is set to a predetermined operation angle, e.g., a maximum operation angle, based on a value output from an air-fuel ratio sensor so as to minimize a variation in an fuel injection quantity between the plurality of cylinders by that exhaust gas air-fuel ratio. That is, the exhaust gas air-fuel ratio of the plurality of cylinders, in which the valve opening characteristics of the intake valve and an exhaust valve are set such that the intake air amount to be introduced into the plurality of cylinders is limited by the opening amount of a throttle valve, for example, and not limited by the valve opening characteristics of the intake valve or the exhaust valve is calculated, and the variation in the fuel injection quantity among the plurality of cylinders is then reduced by that exhaust gas air-fuel ratio.

Abstract: In an adaptation (4, 5, 6, 7) of differences in injected quantities within high operating ranges, the differences are based on an injection parameter and are determined by regulating an irregular operation in an operating point within the lower operating ranges. The injection parameter which determines the differences in injected quantities in the lower operating point is set on a value different from the normal operating value in this point. The dynamics of the operating point varying with the corresponding parametric value of injection is limited during adaptation (4, 5, 6, 7).

Abstract: An operating method is for a piston engine (1). The piston engine includes a plurality of cylinders (6) having intake valves (9), exhaust valves (10), combustion chambers (7), and pistons (8). A fresh gas system (2) contains an extra valve (13) assigned to the cylinders (6), a fuel system (5) and an exhaust system (4). The smooth running of the piston engine (1), includes having a fuel/fresh gas ratio in the exhaust gas being measured selectively for each cylinder in the exhaust system (4). The fuel system (5) is operated in such a way that it supplies the same amount of fuel to all combustion chambers (7) in steady-state operation of the piston engine (1). The extra valve (13) is operated in such a way that the quantity of fresh gas supplied to the combustion chambers (7) in steady-state operation is adjusted selectively for each cylinder as a function of the measured fuel/fresh gas ratio.

Abstract: A method and a device for controlling an internal combustion engine, in which a noise variable is compared to a setpoint value, and an actuating variable is specified based on the comparison. The noise variable is computed using a weighted summation of at least two characteristics.