Abstract: The aim of the inventive method is to improve the emission values of an internal combustion engine during idling following a cold start. Said aim is achieved by inferring an adaptive value for the required fuel quantity from a characteristic curve in accordance with the temperature of the internal combustion engine and verifying during continuous lambda regulation whether predetermined adaptation conditions are met. If so, an adaptive value is determined from the parameters of the lambda regulator and the characteristic curve is adjusted according the newly determined adaptive value and the measured temperature of the internal combustion engine.

Abstract: Method of regulating an internal combustion engine in order to reach presettable nitrogen oxide emission values of the internal combustion engine, wherein the internal combustion engine is supplied at least some of the time with a first fuel and at least some of the time with a second fuel, the quantity of the first fuel supplied to the internal combustion engine per unit of time being controlled according to a preset control actual value or kept constant and the quantity of the second fuel supplied to the internal combustion engine per unit of time to reach a presettable nitrogen oxide emission value being regulated according to at least one recorded engine parameter.

Abstract: A control apparatus for an internal combustion engine can avoid overcorrection at a lean side of air fuel ratio learning correction by unburnt fuel in a blowby gas, and prevent rotational speed reduction and engine stall during air fuel ratio open-loop control after restarting of the engine. A temperature detecting section detects the temperature of the engine based on signals of various sensors, and an air fuel ratio learning correction value changing section updates an air fuel ratio learning correction value in accordance with the engine operating condition. When the engine is stopped with its temperature having not yet reached a predetermined value after started from a cold state thereof, an amount of update of the air fuel ratio learning correction value at a lean side is set in such a manner that the lower a temperature parameter immediately before engine starting, the smaller does the amount of update become.

Abstract: In a hybrid vehicle driven by a dual injection internal combustion engine including an injector for in-cylinder injection and an injector for in-intake air path injection, and assistive dynamic, to control learning of the internal combustion engine's air fuel ratio learning value to learn the engine's air fuel ratio the engine is steadily operated and only any one of the injectors is allowed to inject fuel, while learning of the air fuel ratio is controlled, and after controlling the learning has completed the other injector is alone allowed to inject the fuel, while learning of air fuel ratio is controlled.

Abstract: In an air/fuel ratio control system for an outboard motor engine, a learned correction coefficient KTIMn used in open-loop control for correcting a basic fuel injection amount to be supplied to the engine, is updated only when the manifold absolute pressure PBA (indicative of engine load) is within a predetermined range relative to the engine speed NE concerned. As a result, the air/fuel ratio can be accurately controlled to one other than the stoichiometric air/fuel ratio, even when an O2 sensor that produces an output whose property only changes near the stoichiometeic air/fuel ratio is used.

Abstract: A fuel control system for a diesel engine includes a first module that calculates a block learn multiplier (BLM) based on a feedback signal during a closed-loop fuel control period. A second module adjusts a base fueling rate of the diesel engine based on the BLM during an open-loop fuel control period.

Abstract: A method for diagnosing a catalytic converter (7), which is arranged in an exhaust-gas system (6) of an internal combustion engine (1) has the steps of: detecting the signal (USHK) of an exhaust-gas probe (9) downstream of the catalytic converter; forming a limit value model amplitude (AHKF) from at least one quantity (ML, n) which occurs upstream of the catalytic converter (7); forming a catalytic converter evaluation quantity (DKATI) whose value increases with increasing deviation of the amplitude (AHK) of the signal (USHK) from the limit value model amplitude (AHKF); evaluating the operability of the catalytic converter (7) on the basis of the catalytic converter evaluation quantity (DKATI); stopping the evaluation when an oxygen-dependent catalytic converter load (KATIN) exceeds or drops below a threshold value. The method is characterized in that the threshold value is pregiven in dependence upon the signal (USHK) of the exhaust-gas probe (9) rearward of the catalytic converter.

Abstract: An engine system has an engine control module for controlling a ratio of air and fuel supplied to an engine. The engine control module controls the ratio of air and fuel in relation to a fuel parameter related to the specific energy of the fuel or the stoichiometry of the combustion reaction. The fuel parameter is updated in relation to the engine's performance.

Abstract: A method of operating an internal combustion engine having an; electromagnetically driven intake valves for a vehicle. With the method, deviation of an opening operation of the electromagnetically driven intake valve in response to a command signal for opening the intake valve from a predetermined characteristic is detected, and at least one of parameters used for controlling operation of the internal combustion engine is corrected so as to reduce a change in an intake air charging state in which the internal combustion engine is charge with the intake air. A valve closing timing of the intake valve or a valve closing timing of the exhaust valve that cooperates with the intake valve may be used as parameters to be corrected.

Abstract: A method for calculating transient fuel wall wetting characteristics of an operating engine is described. The method accounts for cylinder valve deactivation of cylinders in the engine in calculating the dynamic fueling compensation. In one example, fuel vaporization effects from fuel puddles in deactivated cylinders is considered when calculating the fueling compensation for active cylinders.

Abstract: A secondary air supplying apparatus of the present invention comprises a secondary air supplying device for supplying secondary air to upstream of an emission purifying device in an exhaust system of an internal combustion engine, a coolant temperature sensor for detecting a temperature of a coolant for the engine, an intake air temperature sensor for detecting a temperature of intake air, a supply controller for actuating the secondary air supplying device in accordance with a predetermined secondary air supply condition, and a summing unit for summing an actuation period of the secondary air supplying device and storing a sum. The supply controller stops the secondary air supply by the secondary air supplying device when the sum stored by the summing unit reaches a predetermined upper limit.

Abstract: A method of controlling fuel input to an engine of a vehicle. A feedback signal is received from a sensor that senses engine exhaust. A dither signal having the same frequency as the feedback signal is applied to a fuel control signal controlling fuel to the engine. A proportional/integral correction is applied to the fuel control signal based on the frequency.

Abstract: Operating method and apparatus for operating an engine controller for an internal combustion engine, including operating in a first operating mode, acquiring at least one state variable (CL, Adap_Fenst_fac, Adap_Fenst_Add) of the internal combustion engine and changing over from the first operating mode into a second operating mode. The changeover from the first operating mode into the second operating mode take place as a function of the determined state variable (CL, Adap_Fenst_fac, Adap_Fenst_Add) of the internal combustion engine.

Abstract: There is described a method of controlling injection in a vehicle internal combustion engine, wherein the intake air flow and exhaust lambda are measured to estimate the fuel quantity actually injected into the engine and perform a closed-loop control whereby the estimated fuel quantity is made to substantially equal the nominal fuel quantity calculated to meet vehicle user requirements. More specifically, the difference between the nominal fuel quantity and the estimated fuel quantity is used to calculate a correction factor by which to correct the nominal fuel quantity.

Abstract: An electronic control unit (ECU) of an injection control system of an internal combustion engine measures an engine rotation speed in a period from a time point when an exhaust valve opens to a time point when a top dead center of a next cylinder is detected after a single injection is performed. The ECU calculates a rotation speed fluctuation caused by the single injection based on the engine rotation speed. The engine rotation speed provided immediately after the single injection is measured after a cylinder pressure increased by the single injection decreases to substantially the same level as the cylinder pressure provided in the case where the single injection is not performed. Therefore, the rotation speed fluctuation corresponding to torque generated by the single injection can be measured accurately.

Abstract: An injection quantity control apparatus for accurately performing an injection quantity learning process in a diesel engine creates an environment for obtaining a characteristic value in a one-to-one relationship with an actual injection quantity. A controller performs a one-shot injection operation for a cylinder of an engine while the environment is established. An injection command quantity is corrected based on an engine speed variation caused by the one-shot injection. After establishment of the condition and before the injection, the opening of a valve is controlled to be smaller than a reference and an opening of each of a diesel throttle and variable turbocharger is controlled to be larger than a reference. A composition of an air flowing into a combustion chamber is stabilized to ensure that the characteristic value detected after the one-shot injection is in a one-to-one relationship with the actual injection quantity.

Abstract: An electronic control unit (an ECU) of a fuel injection system performs a learning injection based on a learning injection quantity and obtains multiple influence values of an operating state of an engine generated through the learning injection. The ECU calculates a learning value for correcting the injection quantity in a normal operation based on the multiple influence values. The ECU determines whether the influence value obtained during the learning injection is within a predetermined range of the influence value. The ECU calculates a provisional learning injection quantity for bringing a subsequent influence value into the predetermined range if the influence value obtained in an early stage of the obtainment is out of the predetermined range. Then, the ECU calculates the other influence values by performing the other learning injections based on the provisional learning injection quantity.

Abstract: A method for operating an internal combustion engine, permitting a differentiation between an air error and a fuel error as part of mixture adaptation. In at least one operating state of the internal combustion engine a deviation in an air-fuel mixture ratio from a setpoint value is corrected. For this correction in the at least one operating state the particular deviation in the air-fuel mixture ratio is determined for at least two setpoint values. From these deviations an air error and/or a fuel error is determined.

Abstract: There is provided a control system capable of realizing a highly robust control having a large margin of stability. The ECU of the control system controls the air-fuel ratio of exhaust gases emitted from the first to fourth cylinders. The ECU 2 estimates an estimation value of a detected air-fuel ratio, from a model defining a relation between the estimation value and a plurality of simulation values, and identifies an intake air amount variation coefficient such the estimation value becomes equal to a detected air-fuel ratio.

Abstract: A spark ignition engine (2) has a fuel injector (8) in an intake port (7). An engine rotation speed sensor (9) detects the rotation speed of the engine (2). The controller (1) determines the target fuel injection amount of the fuel injector (8) during startup of the engine (2) by correcting the basic injection amount in response to the trend in the variation in the engine rotation speed. When the rotation speed of the engine (2) decreases, the controller (1) sets the target fuel injection amount to be smaller than when the rotation speed of the engine (2) is increasing at an identical rotation speed. As a result, effects on the air-fuel ratio related to wall flow relative to fluctuations in the rotation speed of the engine (2) are eliminated and the control accuracy of the air-fuel ratio of the engine (2) is improved.

Abstract: A control system for an internal combustion engine having at least one control device that affects an air-fuel ratio of an air-fuel mixture to be supplied to the engine, is disclosed. An air-fuel ratio correction coefficient is calculated for correcting an amount of fuel to be supplied to the engine so that the detected air-fuel ratio coincides with a target air-fuel ratio. An air-fuel ratio affecting parameter indicative of a degree of influence that an operation of the control device exercises upon the air-fuel ratio, is calculated. A correlation parameter which defines a correlation between the air-fuel ratio correction coefficient and the air-fuel ratio affecting parameter is calculated using a sequential statistical processing algorithm. A learning correction coefficient relating to a change in characteristics of the control device is calculated using the correlation parameter. The air-fuel ratio is controlled using the air-fuel ratio correction coefficient and the learning correction coefficient.

Abstract: An air fuel ratio control apparatus for an internal combustion engine can improve learning accuracy in the air fuel ratio control even if the air fuel ratio of a mixture detected by an air fuel ratio detection device shifts from an actual air fuel ratio thereof. The apparatus controls the air fuel ratio of an exhaust gas flowing into an exhaust gas purification device based on an air fuel ratio feedback value and an air fuel ratio learning value. A temperature detection device detects the temperature of the exhaust gas purification device. A determination device determines, based on a difference between a detection value of the temperature detection device and a target temperature, that the air fuel ratio detection device shifts to a rich or lean side. The update of the air fuel ratio learning value is inhibited when the air fuel ratio detection device shifts to a rich or lean side.

Abstract: An evaporative emission control system includes a canister for collecting fuel vapor from a fuel tank, and a purge control valve disposed between the canister and the intake passage of the engine. A controller of the system determines a failure of the purge control valve, executes a purging process by opening the purge control valve, executes a learning process for learning the fuel concentration of the purge gas, and executes a correcting process for correcting the amount of fuel injected into the engine based on the learned value of the fuel concentration. When the purge control valve is normal and conditions for execution of purge control are satisfied, the controller requests execution of the purging process, learning process and the correcting process. When an open failure occurs in the purge control valve, the controller always requests execution of the learning process and the correcting process.

Abstract: Fuel properties estimating apparatus for an internal combustion engine includes a controller to determine an estimated component concentration of a component such as alcohol in a fuel. The controller calculates a new value of the estimated component concentration in accordance with a component concentration variation and a stored previous value of the estimated component concentration. From an air-fuel ratio correction quantity calculated from an actual air fuel ratio, for correcting a fuel injection quantity, the controller calculates the component concentration variation by using a conversion function determined by the previous value of the component concentration.

Abstract: An exhaust gas purifying apparatus adopted to an internal combustion engine provided with air-fuel ratio learning means for learning a primary air-fuel ratio given in the form of a mass ratio between air and fuel introduced into a combustion chamber, comprises an exhaust gas purifying catalyst provided in an exhaust gas passage of the engine and a catalyst activating means for supplying secondary air to an upstream of the exhaust gas purifying catalyst and increasing the quantity of fuel supplied to the engine to activate the exhaust gas purifying catalyst.

Abstract: An output signal from a downstream-side exhaust gas sensor is fed back into a fuel injection rate so that the air-fuel ratio of the exhaust gases flowing out from a catalyst may match a reference value. In this sub-feedback control process, the integral value of the deviation between the output signal of the downstream-side exhaust gas sensor and a reference value is calculated, and the resulting integral-data signal is smoothed. A learning value for compensating for the permanent error included in an air-fuel ratio signal from an A/F sensor is learnt from the integral-data signal generated by the above smoothing operation.

Abstract: In an air-fuel ratio feedback control for an engine, a cylinder-by-cylinder variation value is calculated for each cylinder based on changes of intake pipe pressure detected by an intake pipe pressure sensor, or the like, and a fuel injection amount or the like is corrected for each cylinder based on the variation value. When the variation is large during an engine operation, or until the variation correction is completed, it is determined that the output of an exhaust gas sensor will be disturbed by the variation and an air-fuel ratio feedback correction amount will be disturbed. Therefore, a control gain of the air-fuel ratio feedback control is changed to a value smaller than a normal value, or the feedback control is inhibited.

Abstract: A method for compensating for mismatches of the precontrol of a fuel metering for an internal combustion engine. A regulation being superimposed on the precontrol. At least one correction quantity being formed, from the behavior of the regulation at high temperatures of the internal combustion engine, which influences the fuel metering even at low temperatures of the internal combustion engine in a supplementing manner to the superimposed regulation for compensating for the mismatches. At low temperatures a further correction quantity is formed which acts upon the fuel metering, whose effect at low temperatures of the internal combustion engine is greater than at high temperatures.

Abstract: A method is disclosed for controlling operation of an engine coupled to an exhaust treatment catalyst. Under predetermined conditions, the method operates an engine with a first group of cylinders combusting a lean air/fuel mixture and a second group of cylinders pumping air only (i.e., without fuel injection). In addition, the engine control method also provides the following features in combination with the above-described split air/lean mode: idle speed control, sensor diagnostics, air/fuel ratio control, adaptive learning, fuel vapor purging, catalyst temperature estimation, default operation, and exhaust gas and emission control device temperature control. In addition, the engine control method also changes to combusting in all cylinders under preselected operating conditions such as fuel vapor purging, manifold vacuum control, and purging of stored oxidants in an emission control device.

Abstract: A schedule (164, 166) correlates data values of closed-loop gain (KP, KI) with engine temperature values (EOT) and engine speed values (N). A control strategy develops a data value (ICPC_DES) representing desired injector control pressure (ICP) set-point, processes ICPC_DES and a data value (ICP_MPA) representing actual ICP to develop ICP error data value (ICP_ERR) for closed-loop P-I control (160, 162) of actual ICP. Data values for closed-loop proportional and integral gains are obtained from the schedule based on measured engine temperature and measured engine speed. ICP become less subject to undesirable fluctuations that might otherwise change fuel injection quantity in ways detrimental to attainment of desired tailpipe emission objectives.

Abstract: An evaporative emission control system detects an opening failure of a purge control valve that controls the amount of purge gas flowing from a canister into an intake passage of the engine, and determines whether a significant shift occurs in an air/fuel ratio feedback factor when the opening failure is detected. If the air/fuel ratio feedback factor is shifted to the rich side, a rich-side initial value is set to a vapor concentration learned value, and, if the feedback factor is shifted to the lean side, a lean-side initial value is set to the vapor concentration learned value. These initial values give larger changes to the vapor concentration learned value than update amounts by which the learned value is updated during normal learning control.

Abstract: An electronic control unit (an ECU) of a fuel injection system performs a learning injection based on a learning injection quantity and obtains multiple influence values of an operating state of an engine generated through the learning injection. The ECU calculates a learning value for correcting the injection quantity in a normal operation based on the multiple influence values. The ECU determines whether the influence value obtained during the learning injection is within a predetermined range of the influence value. The ECU calculates a provisional learning injection quantity for bringing a subsequent influence value into the predetermined range if the influence value obtained in an early stage of the obtainment is out of the predetermined range. Then, the ECU calculates the other influence values by performing the other learning injections based on the provisional learning injection quantity.

Abstract: A fuel supply control system for an internal combustion engine wherein a basic fuel amount supplied to said engine can be calculated according to the intake air flow rate detected by said intake air flow rate sensor. An air-fuel ratio correction coefficient can be calculated for correcting an amount of fuel to be supplied to the engine so that the detected air-fuel ratio coincides with a target air-fuel ratio. At least one correlation parameter vector which defines a correlation between the air-fuel ratio correction coefficient and the intake air flow rate detected by the intake air flow sensor, can be calculated using a sequential statistical processing algorithm. A learning correction coefficient relating to a change in characteristics of the intake air flow rate sensor can be calculated using the correlation parameter. An amount fuel to be supplied to the engine can be controlled using the basic fuel amount, the air-fuel ratio correction coefficient, and the learning correction coefficient.

Abstract: Fuel properties estimating apparatus for an internal combustion engine includes a controller to determine an estimated component concentration of a component such as alcohol in a fuel. The controller calculates a new value of the estimated component concentration in accordance with a component concentration variation and a stored previous value of the estimated component concentration. From an air-fuel ratio correction quantity calculated from an actual air fuel ratio, for correcting a fuel injection quantity, the controller calculates the component concentration variation by using a conversion function determined by the previous value of the component concentration.

Abstract: In an exhaust system of an internal combustion engine, an air-fuel ratio sensor is located upstream of a three-way catalyst. An oxygen sensor is located downstream of the catalyst. An ECU performs feedback control of the amount of fuel based on output of the air-fuel ratio sensor such that the engine air-fuel ratio seeks a stoichiometric air-fuel ratio. The ECU also performs sub-feedback control for correcting the amount of fuel in the feed back control based on output of the oxygen sensor. The ECU learns a learning value for compensating for a stationary difference between the engine air-fuel ratio and the stoichiometric air-fuel ratio based on a sub-feedback correction value. When learning of the learning value is performed after the learning value is cleared, a slip control by a lockup clutch is inhibited until the learning is stabilized.

Abstract: A method is disclosed for controlling operation of an engine coupled to an exhaust treatment catalyst. Under predetermined conditions, the method operates an engine with a first group of cylinders combusting a lean air/fuel mixture and a second group of cylinders pumping air only (i.e., without fuel injection). In addition, the engine control method also provides the following features in combination with the above-described split air/lean mode: idle speed control, sensor diagnostics, air/fuel ratio control, adaptive learning, fuel vapor purging, catalyst temperature estimation, default operation, and exhaust gas and emission control device temperature control. In addition, the engine control method also changes to combusting in all cylinders under preselected operating conditions such as fuel vapor purging, manifold vacuum control, and purging of stored oxidants in an emission control device.

Abstract: An engine control system provides a gas concentration detection output irrespective of variation in product or change due to passage of time using an on-vehicle exhaust gas sensor. An exhaust gas sensor 107 and an electric heater 119 are connected to a microprocessor 120a, and an oxygen-concentration detection output Ip of exhaust gas, a calibration signal Vc and an internal resistance detection signal Vr are inputted through A/D converter 125. A program memory 121a stores standard characteristic data of the exhaust gas sensor 107. An atmospheric air oxygen-concentration detection output Ip0 under fuel-cut drive is measured and monitored. The electric heater 119 controls temperature so that the output coincides with the stored value. Current internal resistance of the exhaust gas sensor 107 is read and stored as target resistance. In normal driving, the electric heater 119 is controlled so that the internal resistance becomes the target resistance.

Abstract: The present invention is constituted so that an actual air-fuel ratio is detected by an air-fuel ratio sensor, a plant model representing a plant between a fuel injection valve and the air-fuel ratio sensor is sequentially identified to calculate parameters of the plant model, a control gain for calculating a feedback control amount is calculated using the calculated parameters, and the feedback control amount is calculated using the calculated control gain, wherein an absolute value of an input side parameter set on an input side of the plant model is limited to be a predetermined limit value or above, among the calculated parameters.

Abstract: Fuel properties estimating apparatus for an internal combustion engine includes a controller to determine an estimated component concentration of a component in a fuel. The controller calculates an air-fuel correction quantity in accordance with an actual air fuel ratio of the engine; and calculates an air-fuel ratio sensitivity correction quantity from the air-fuel ratio correction quantity and a fuel properties correction quantity calculated from a most recent value of the component concentration. The controller then determines a new value of the estimated component concentration in accordance with the air-fuel ratio sensitivity correction quantity.

Abstract: A method is described for controlling fuel vapor purging and adaptive learning in a lean burn engine system. Fuel vapor purging is carried out during lean operating conditions to minimize impact on vehicle emissions, while adaptive learning is carried out during near stoichiometric conditions (oscillations around stoichiometry). This allows faster fuel vapor purging and additional adaptive learning opportunity.

Abstract: A method is described for controlling fuel vapor purging and adaptive learning in a lean burn engine system. Fuel vapor purging is carried out during lean operating conditions to minimize impact on vehicle emissions, while adaptive learning is carried out during near stoichiometric conditions (oscillations around stoichiometry). This allows faster fuel vapor purging and additional adaptive learning opportunity.

Abstract: A fuel injection is carried out as n split injections. Each of injection quantities is defined by dividing an injection quantity into n fuel injections. A FCCB correction and an ISC correction are carried out while n split injection cycles are performed. A value obtained by adding up an FCCB correction for each injection cycle and an ISC correction for each injection cycle is updated and stored as a learned injection quantity. The learned injection quantity is calculated as an injection quantity correction for each cylinder to be added to a command injection quantity for each injection cycle.

Abstract: A method is described for estimating cylinder airflow in engines that operate with manifold pressure near atmospheric pressure to compensate for degraded sensor response at such conditions. The method uses an adaptive approach that is updated under preselected engine operating conditions to thereby allow improved accuracy across a variety of engine operation.

Abstract: A method and apparatus for automatic tuning of fuel injected engines includes an air-fuel ratio sensor, a load device for controlling engine RPM, a digital computer and a display device. The digital computer displays a plurality of throttle positions to an operator who sets the throttle of said engine to correspond to said display of throttle position. The digital computer varies the engine RPM over the operating range of the engine to determine corresponding map values for storage in an injector signal modifier.

Abstract: An evaporative fuel processing system for an in-cylinder injection type internal combustion engine includes an evaporative fuel processing mechanism that includes a canister to which an evaporative fuel in a fuel supply system is adsorbed and performs an operation for purging the adsorbed evaporative fuel into an intake system of the internal combustion engine. The system further includes a controller that estimates a degree of dilution occurred in a lubricating oil for the internal combustion engine with a fuel mixed therewith, and inhibits the purging operation performed by the evaporative fuel processing mechanism when the estimated degree of dilution is equal to or larger than a predetermined value.

Abstract: A method is disclosed for controlling operation of an engine coupled to an exhaust treatment catalyst. Under predetermined conditions, the method operates an engine with a first group of cylinders combusting a lean air/fuel mixture and a second group of cylinders pumping air only (i.e., without fuel injection). In addition, the engine control method also provides the following features in combination with the above-described split air/lean mode: idle speed control, sensor diagnostics, air/fuel ratio control, adaptive learning, fuel vapor purging, catalyst temperature estimation, default operation, and exhaust gas and emission control device temperature control. In addition, the engine control method also changes to combusting in all cylinders under preselected operating conditions such as fuel vapor purging, manifold vacuum control, and purging of stored oxidants in an emission control device.

Abstract: Gas containing fuel vapor is purged as purge gas from a canister to an intake passage through a purge line. An ECU computes purge flow rate, which is the flow rate of the purge gas, and computes vapor concentration, which is the concentration of the fuel vapor contained in the purge gas. The ECU obtains a concentration correction value in accordance with the rate of change of the computed purge flow rate. The ECU correct the computed vapor concentration by using the concentration correction value and by taking into consideration of the time at which the purge flow rate is computed and the time at which purge gas having the computed flow rate is drawn into the combustion chamber. The ECU sets the fuel supply amount in accordance with the computed purge flow rate and the corrected vapor concentration. As a result, the accuracy of the air-fuel ratio control during purging is improved.

Abstract: An O2 amount in the intake air is determined based on a fresh air and an EGR gas. A consumed O2 amount is determined with a command injection amount Qr. Then, the consumed O2 amount is subtracted from the O2 amount in the intake air to obtain an exhaust O2 amount. An exhaust O2 concentration is estimated based on the exhaust O2 amount. According to the invention, the system is not affected by a delay for the exhaust gas to reach an O2 sensor and a delay of the chemical reaction in the O2 sensor. Therefore, the exhaust O2 concentration can be highly precisely estimated compare to the case in which the exhaust O2 concentration is detected by the O2 sensor.

Abstract: A fuel pressure control for an alternate-fuel engine utilizes adaptively learned corrections for fuel injection pulsewidth to dynamically adjust a base fuel pressure control signal. The resulting fuel pressure control can thus be characterized as open-loop with closed-loop correction based on air/fuel ratio error. The control dynamically adjusts the fuel pressure in a manner to optimize the air/fuel ratio control instead of controlling to a predetermined pressure, and fuel pressure measurement is not required.

Abstract: A method is introduced for compensating for mismatches of the precontrol of a fuel metering for an internal combustion engine[,].A [−a] regulation being superimposed on the precontrol[,].At [− and at] least one correction quantity being formed, from the behavior of the regulation at high temperatures of the internal combustion engine, which influences the fuel metering even at low temperatures of the internal combustion engine in a supplementing [way] manner to the superimposed regulation for compensating for the mismatches[, and − at] At low temperatures a further correction quantity is formed which acts upon the fuel metering, and [−] whose effect at low temperatures of the internal combustion engine is greater than at high temperatures.