Abstract: To keep catalyst purification efficiency high and prevent deterioration of emission performance. Therefore, an internal combustion engine control device according to an aspect of the present invention includes: an oxygen storage ratio calculation unit that calculates an oxygen storage ratio of a catalyst based on a catalytic reaction model having at least a detection value of a first exhaust gas sensor disposed on an upstream side of the catalyst as an input; a statistical model calculation unit that predicts a catalyst downstream exhaust gas concentration using a statistical model having an oxygen storage ratio as an input and a catalyst downstream exhaust gas concentration as an output; and an air-fuel ratio correction amount calculation unit that calculates an air-fuel ratio correction amount of an air-fuel mixture of an internal combustion engine based on a future catalyst downstream exhaust gas concentration calculated by the statistical model calculation unit.

Abstract: In accordance with exemplary embodiments, methods and systems are provided for controlling fuel injection by a fuel injector of a direct injection engine. In one embodiment, a method includes: storing, in a first data storage device, a first table of values; storing, in a second data storage device, a second table of values; and adjusting, via instructions provided by a processor of the vehicle, a minimum mass value used to control the fuel injection based on an injector learned value, the first table, and the second table, wherein the injector learned value is set based on an amount of injector learning completed.

Abstract: Systems, methods and apparatuses for vaporizing all or substantially all plant matter, liquid and/or other material to be vaporized are disclosed. Embodiments of the invention comprise a vaporization chamber sealed except for at least two conduits, heating element, a first conduit coupled to a source of fully or almost fully non-oxygenated gas, a heating element capable of heating the vaporization chamber to a temperature above a combustion temperature, a second conduit configured to transport vaporization gases and vaporized elements out of the vaporization chamber and at least one valve positioned in the second conduit preventing the flow of atmospheric air into the vaporization chamber. In some instances, the first gas substantially clears the vaporization chamber of atmospheric air prior to reaching combustion temperature. A second gas containing oxygen may be intermixed with the vaporization gases and vaporized elements proximal to the combustion chamber.

Abstract: A control system of an internal combustion engine comprises an air-fuel ratio sensor 40, 41 detecting an air-fuel ratio of exhaust gas, a current detecting device 61 detecting an output current of the air-fuel ratio sensor, a voltage applying device 60 applying voltage to the air-fuel ratio sensor, and a voltage control part 81 configured to control voltage applied to the air-fuel ratio sensor through the voltage applying device. The voltage control part is configured to set the applied voltage to a reference voltage determined so that the output current becomes zero when an air-fuel ratio of inflowing exhaust gas flowing into the air-fuel ratio sensor is a stoichiometric air-fuel ratio, and correct the reference voltage so that the output current detected by the current detecting device becomes zero when it is judged that the air-fuel ratio of the inflowing exhaust gas is the stoichiometric air-fuel ratio.

Abstract: The present invention relates to a system for coping with a malfunction of an ethanol sensor of a FFV. The present invention provides a system for coping with a malfunction of an ethanol sensor of a FFV, the system including: a driving condition detector configured to determine whether a driving condition of the FFV is satisfied; an air-fuel ratio control condition detector configured to determine whether an air-fuel ratio control condition is satisfied; a timer unit configured to calculate a timer value by measuring time when an ethanol content value measured in the ethanol sensor is constant and when the driving condition and the air-fuel ratio control condition are satisfied; and a controller configured to synchronize an ethanol-content learned value with the ethanol content value measured in the ethanol sensor when it is determined that the timer value calculated in the timer unit is higher than a preset critical value.

Abstract: Provided is an engine control device for correcting output characteristics of an oxygen sensor and performing air-fuel ratio feedback control. The engine control device includes various sensors for detecting operating state information of an engine, an oxygen sensor, and air-fuel ratio feedback controller to adjust an amount of fuel injected into the engine, on the basis of the operating state information and an output voltage value of the oxygen sensor, wherein the air-fuel ratio feedback controller calculates, in accordance with the operating state information based on detection results from the various sensors, a coefficient for correcting the output voltage value, implements air-fuel ratio feedback control on the basis of an air-fuel ratio feedback control correction amount calculated using a corrected oxygen sensor output voltage value calculated on the basis of the coefficient, and adjusts the amount of fuel injected into the engine.

Abstract: An exhaust device for a saddle-type vehicle having a pipe section with respect to a vehicle body and housing a catalyzer therein, and a muffler connected to a rear end of the pipe section includes an upstream oxygen sensor positioned upstream of the catalyzer and a downstream oxygen sensor positioned downstream of the catalyzer. The downstream oxygen sensor is disposed in either a position overlapping a main stand for supporting a motorcycle as viewed from below the vehicle body when the main stand is stored, or a position overlapping a stand receiver for abutting against the main stand as viewed from below the vehicle body when the main stand is stored. The pipe section includes a larger-diameter portion having an increased diameter for housing the catalyzer therein.

Abstract: A control and evaluation unit for the operation and evaluation of at least one sensor, in particular for the operation and evaluation of at least one lambda probe of an internal combustion engine, signal inputs being disposed for the reception of analog measured signals of the at least one sensor, received analog measured signals being digitized by way of an analog/digital converter, a signal transfer unit, by way of which digitized signals are transferred to a calculation unit, being disposed, and provision being made in particular that the signal inputs are switchable by way of a multiplexer.

Abstract: An exhaust device includes left and right exhaust pipes and mufflers connected to a downstream side of the left and right exhaust pipes. The pair of left and right exhaust pipes respectively includes a merging portion. A catalyst is provided to the merging portion respectively. The pair of left and right exhaust pipes respectively includes, on a downstream side of the catalyst, a branching portion that has one side thereof extending to the muffler and the other side thereof extending to a connecting pipe. An oxygen sensor is provided to one side on a downstream side of the pair of left and right branching portions.

Abstract: This control device for an internal combustion engine includes: an exhaust purification catalyst that is provided in an exhaust passage of the internal combustion engine; a downstream air-fuel ratio sensor that is provided downstream of the exhaust purification catalyst; and an air-fuel ratio control device that controls such that the air-fuel ratio of exhaust gas flowing into the exhaust purification catalyst reaches a target air-fuel ratio. The downstream air-fuel ratio sensor is configured such that the applied voltage thereof at which the output current becomes zero decreases as the exhaust air-fuel ratio increases. If the target air-fuel ratio is richer than the reference air-fuel ratio, the voltage applied to the downstream air-fuel ratio sensor is set to a higher voltage than the voltage at which the output current becomes zero when the exhaust air-fuel ratio is the stoichiometric air-fuel ratio.

Abstract: Methods and systems are provided for accurately learning the zero point of an intake gas oxygen sensor in varying ambient humidity conditions. The learned zero point is corrected based on an estimated ambient humidity to calibrate the reading for dry air conditions or standard humidity conditions. EGR control is performed by comparing the output of an intake oxygen sensor during EGR conditions relative to the humidity-corrected zero point.

Abstract: The invention relates to a method for carrying out a zero point adaptation of a lambda probe (16) in an exhaust gas discharge section (4) of an internal combustion engine (2), wherein fresh air is pumped, during an after-run period following a deactivation of the internal combustion engine (2), from an air supply system (3) into the exhaust gas discharge section (4) such that fresh air flows around the lambda probe (16).

Abstract: An internal combustion engine has an exhaust gas sensor upstream of or in an exhaust gas catalytic converter, and having a measurement signal corresponding to a residual oxygen content of the exhaust gas flowing past the exhaust gas sensor. For operation, an air ratio is specified, a specified forced stimulation is applied thereto, and at least one actuator that influences the mixture is set by appropriately controlling the actuator. In correlation with a rising edge of the forced stimulation, a first maximum value of the air ratio is determined according to the signal profile of the exhaust gas sensor measurement signal during a first measurement duration, and a second maximum value of the air ratio is determined according to the exhaust gas sensor measurement signal during a subsequent second measurement duration. A first sensor characteristic value is determined based on the first and second maximum values.

Abstract: Some implementations of a system for controlling an internal combustion engine (e.g., a natural gas fired internal combustion engine or another type of engine) can include an air-fuel ratio controller that is configured to monitor sensor feedback from an exhaust path and to thereafter automatically adjust the air-fuel mixture. The system can be employed in particular methods to control emissions from the engine, for example, by reducing pollutants emitted as components of the exhaust from the engine.

Abstract: In a control method suitable for an internal combustion engine (1) of a motor vehicle with an automatic engine cut-off and starting system (33) by which the internal combustion engine (1) can be cut off and started independently from the driver of the motor vehicle, the starting of the internal combustion engine (1) is detected and a variable determined, which represents a measure for the work performed by the internal combustion engine (1) since it has been started. The cut-off of the internal combustion engine (1) is controlled by the automatic engine cut-off and starting system (33) according to the variable.

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

Abstract: A passive control device is interposable between an oxygen sensor and an electric control unit of a motor vehicle to modify a reference voltage used by the electric control unit so that a richer fuel mixture is provided to an internal combustion engine of the motor vehicle than would otherwise be provided in absence of the passive control device. The passive control device directly passes the voltage signal from the oxygen sensor to the electronic control unit without modification. The passive control device works with the electronic control unit to provide a richer fuel mixture without reprogramming the electronic control unit.

Abstract: A gas sensor apparatus 3 in an air-fuel ratio detection system 1 includes a gas sensor element 4 which outputs a detection signal corresponding to air-fuel ratio, and a gas sensor control circuit 2 which includes a detection section 20 for outputting a first output signal VIP1, a second output signal VIP2, and a third output signal VIP3 in accordance with the detection signal. This detection section 20 outputs the first output signal VIP1 which changes in accordance with the air-fuel ratio at least within a wide first air-fuel ratio zone, the second output signal VIP2 which changes in accordance with the air-fuel ratio within a narrow zone in the vicinity of the stoichiometric ratio, and the third output signal VIP3 which changes in accordance with the air-fuel ratio within a narrow zone in the lean region.

Abstract: An interface device for a gas sensor includes a detection resistor having first and second ends to generate voltages by a current output of the gas sensor, a differential amplifier having first and second input terminals to receive the voltages of the first and second resistor ends and an output terminal to output a voltage according to a difference between the voltages of the first and second resistor ends, a first switching element to transmit the voltage of the first resistor end to the first input terminal of the differential amplifier in a transmission state and interrupt transmission of the voltage of the first resistor end to the first input terminal of the differential amplifier in an interruption state and a second switching element turned on to establish continuity between the first and second input terminals of the differential amplifier when the first switching element is in the interruption state.

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

Abstract: A method and system is disclosed which relates to controlling a stationary gaseous-fueled internal combustion engine. The method may include measuring an air to fuel ratio of the engine, calculating a difference between the measured air to fuel ratio and a desired air to fuel ratio for the engine, and automatically controlling an air to fuel mixture supplied to the engine in accordance with the calculated difference to enable the engine to run at substantially the desired air to fuel ratio.

Abstract: A method for operating a flex fuel conversion system for efficiently providing an aftermarket fuel delivery system which allows a vehicle to be operated on gasoline, ethanol or any combination of gasoline and ethanol.

Abstract: The air-fuel-ratio control apparatus for an internal combustion engine obtains an upstream-side feedback correction value DFi for feedback-controlling an air-fuel ratio on the basis of a value (Fcrlow(k?N)) that is obtained by performing a low-pass filter process with a time constant ? to a value corresponding to an upstream-side target air-fuel ratio abyfr at the time point a dead time, which corresponds to the period from a time when the instruction for injecting fuel to the time when exhaust gas generated based up on a combustion of the fuel reaches an upstream air-fuel-ratio sensor 66, before the present point in time, and a value (Fc(k?N)) corresponding to an output value Vabyfs from the upstream air-fuel-ratio sensor 66 at the present time. The time constant ? of the low-pass filter process is set to a value equal to the time constant of the response delay of the upstream air-fuel-ratio sensor 66.

Abstract: A compensation circuit (KS) is provided between the output of a differential amplifier (Diff_Amp) and the input of a controller (R). The compensation circuit generates a compensation signal, whose characteristic curve approximates to that of the parasitic signal, with the same amplitude and frequency (Phi1) as the parasitic signal, but by 180 DEG out of phase. The compensation signal is subtracted from the differential signal (DELTA Vs) and allows the parasitic signal to be eliminated to a great extent.

Abstract: In a variable cam timing (VCT) system (10a) which has a feedback control loop wherein an error signal (36) relating to at least one sensed position signal of either a crank shaft position (24a) or at least one cam shaft position (22a) is fed back for correcting a predetermined command signal (12). The system further includes a valve (14) for controlling a relative angular relationship of a phaser (42); and includes a variable force solenoid (20) for controlling a translational movement of the valve (14). An improved control method comprising the steps of: providing a dither signal (38) sufficiently smaller than the error signal (36); as temperature varies, changing at least one parameter relating to the dither signal (38); and applying the dither signal (38) upon the variable force solenoid (20), thereby using the dither signal (38) for overcoming a system hysteresis without causing excessive movement of valve (14).

Abstract: A temperature of an oxygen concentration detector generating an electromotive force according to a difference between oxygen concentration in an engine exhaust gas and oxygen concentration in the atmosphere, is detected, and coefficients in a transformation for converting the electromotive force to a value having a characteristic linear to an air-fuel ratio is modified according to the temperature.

Abstract: A system for improving the performance of a motor vehicle internal combustion engine includes a controller positioned between an O2 sensor. The controller alters the O2 sensor signals and adjusts supplemental sensor signals received from supplemental sensors and sends the altered O2 signals and the adjusted supplemental sensor signals to a programmed electronic control unit which controls operation of fuel injectors.

Abstract: When in controlling an air-fuel ratio by a feedback control, a target air-fuel ratio is changed between normal time and at rich control time, a difference between a change amount of the target air-fuel ratio and a change amount of an air-fuel ratio feedback correction coefficient is learned as a sensor error in the rich control. A final detected air-fuel ratio is calculated by correcting a detected air-fuel ratio of an air-fuel ratio sensor in rich control based on the sensor error. Alternatively, the target air-fuel ratio or the air-fuel ratio feedback correction coefficient in the rich control may be corrected based on the sensor error.

Abstract: A response time constant of an A/F ratio control system is calculated in accordance with an engine operating condition. A control gain is calculated based on the response time constant. A degradation index of a response of an A/F sensor is calculated, so as to be used as a parameter representing a model error or aging degree of the A/F control system. The control gain is corrected with a correction coefficient corresponding to the model error. An A/F feedback correcting amount is calculated using the response time constant, the control gain and a deviation between a detected A/F and a target A/F, so as to decrease the deviation. Thus, the A/F control system is prevented from a degradation caused by aging.

Abstract: A stored relationship between air/fuel ratio and the output voltage of a wide-range exhaust gas oxygen sensor is automatically re-calibrated under any air/fuel ratio condition. Once an engine control module records oxygen sensor voltages under stoichiometric and deceleration fuel cut-off conditions, the air/fuel ratio that corresponding to any sensor voltage can be calculated. In operation, the sensor voltage recorded during fuel cut-off is used to determine first and second lump-sum parameters that relate sensor output voltage to air/fuel ratio under lean and rich operating conditions, respectively. The determined parameters are compared with previously determined values, and when the comparison indicates that at least a predetermined change the sensor operating characteristics has occurred, the parameters are used to re-calibrate the stored sensor voltage vs. air/fuel ratio relationship.

Abstract: When in controlling an air-fuel ratio by a feedback control, a target air-fuel ratio is changed between normal time and at rich control time, a difference between a change amount of the target air-fuel ratio and a change amount of an air-fuel ratio feedback correction coefficient is learned as a sensor error in the rich control. A final detected air-fuel ratio is calculated by correcting a detected air-fuel ratio of an air-fuel ratio sensor in rich control based on the sensor error. Alternatively, the target air-fuel ratio or the air-fuel ratio feedback correction coefficient in the rich control may be corrected based on the sensor error.

Abstract: An intermediate target value calculating unit calculates an intermediate target value &phgr;midtg(i) on the basis of an output &phgr;(i−1) of an A/F ratio sensor in computation of last time and a final target value &phgr;tg(i). By the computation, the intermediate target value &phgr;midtg(i) is set between the output &phgr;(i−1) of the A/F ratio sensor in computation of last time and the final target value &phgr;tg(i). A correction amount calculating unit calculates a correction amount AFcomp(i) of the target A/F ratio on the basis of a deviation &Dgr;&phgr;(i) between the intermediate target value &phgr;midtg(i) and the output &phgr;(i) of the A/F ratio sensor. Consequently, the control is hard to be influenced by variations in waste time of the subject to be controlled and an error in modeling. While maintaining the stability of the A/F ratio feedback control, higher gain can be achieved and robustness can be also increased.

Abstract: A temperature of an oxygen concentration detector generating an electromotive force according to a difference between oxygen concentration in an engine exhaust gas and oxygen concentration in the atmosphere, is detected, and coefficients in a transformation for converting the electromotive force to a value having a characteristic linear to an air-fuel ratio is modified according to the temperature.

Abstract: A control system for a plant, having an identifier and a controller. The identifier identifies model parameters of a controlled object model which is obtained by modeling the plant. The controller calculates a control input to the plant so that an output from the plant coincides with a control target value, using the identified model parameters. The controller calculates a self-tuning control input, using the model parameters identified by the identifier. The controller further calculates a damping control input according to the rate of change in the output from the plant or the rate of change in a deviation between the output from the plant and the control target value. The controller calculates the control input to the plant as a sum of the self-tuning control input and the damping control input.

Abstract: A voltage sensing system that has a pair of input leads having a first input lead, and a second input lead each sensing a non-grounded voltage, and an amplifier coupled to the pair of input leads, the amplifier generating an amplifier output voltage in response to a voltage on the first input lead, a voltage on the second input lead and an offset voltage. The system further includes a controller for receiving the amplifier output voltage and determining an operating range, and an offset voltage generator for generating the offset voltage, the offset voltage generator altering the offset voltage in response to the operating range determined by the controller. An oxygen sensing system using a sample resistance for sensing a bi-directional current may be coupled to the voltage sensing system. A method for sensing air-to-fuel ratio includes sampling an input voltage drop derived from a pumping current across a sampling resistance. The input voltage is indicative of air-to-fuel ratio.

Abstract: An outboard motor engine includes a feedback control system for controlling the air/fuel ratio of the air/fuel mixture combusted within the engine. The control system can be configured to vary the target output value of a combustion condition sensor in accordance with at least one engine operation characteristic, for example, but without limitation, engine speed or throttle position.

Abstract: A method of determining a goal voltage for a fuel/air sensor of an engine electronic fuel injection system includes the steps of determining a goal fuel/air sensor voltage, superimposing a wave form forcing function to the fuel/air sensor voltage for providing a goal fuel/air sensor voltage having a wave form pattern and controlling the engine to operate according to the goal fuel/air sensor voltage. The wave form forcing function provides the required fuel/air perturbations that are required to retain proper oxygen storage of the catalyst to maintain high three-way conversion efficiency.

Abstract: A controller is interposed between the O2 sensor and electronic control unit of a motor vehicle to modify the O2 sensor signals before they are received by the electronic control unit so that a richer fuel mixture is introduced into the internal combustion engine of the motor vehicle than would otherwise be the case.

Abstract: Even when a reaction delay time of an A/F ratio detection device changes, an A/F ratio controller prevents an A/F ratio feedback control from being disturbed. The controller is programmed to calculate an A/F ratio feedback coefficient by proportional term control and integration term control, and to set length of time for said integration term to be carried out in accordance with an operating state of the engine. It is programmed to calculate the integration term based on the set time and to set a proportional term for shifting said A/F ratio feedback coefficient. It is further programmed to detect a deviation between a first A/F ratio feedback coefficient before the integration term is carried out and a second A/F ratio feedback coefficient after the integration term is carried out and the coefficient is shifted by the proportional term set by said means for setting the proportional term. Based on the detected deviation, the length of time for the integration term to be carried out is corrected.

Abstract: The control arrangement comprises an oxygen linear test sensor located along the exhaust duct of an internal combustion engine, the sensor having a chamber able to receive part of the exhaust gas and two electrolytic cells of which one is electrically piloted; the arrangement having a retro-operation test circuit able to adjust the current piloted to the cell to give rise to an oxygen ions draining mechanism from and/or towards the chamber which induces the stoichiometric condition within the chamber itself, and an outlet circuit able to convert the piloted current into a first signal representative of nature of the mixture fed to the engine; the arrangement being provided with a memory circuit which memorises the value of a compensation resistance of the eventual spreads of the piloted current of a correcting circuit receiving the stored value of the compensation resistance and able to ensure a correction for the first signal to recover the spreads of piloted current to the cell; the correcting circuit provi

Abstract: Control method for an oxygen linear sensor, in which the sensor is located along an exhaust duct of an internal combustion engine to receive into a separate chamber part of the exhaust gas and generate a first signal representative of the swing between the composition of the gases in the chamber and a reference stoichiometric composition; the first signal being processed by a retroactive circuit which pilots an electrical current Ip into the sensor in such a manner as to generate an oxygen ion draining mechanism from and towards the chamber and to cancel the swing; the current being converted into an output signal which saving an error due to current spreads, is proportional to the quantity of oxygen present in the exhaust gases; the method presenting the calculation phase of a correction parameter which is applied to the output signal to make it effectively proportional to the quantity of oxygen present in the exhaust gases; the calculation of the parameter being effected with the sensor located in a control

Abstract: A control device for an air-fuel ratio sensor for detecting, from an oxygen concentration detecting device, a current corresponding to a concentration of oxygen contained in a gas by applying a voltage to the oxygen concentration detecting device. The control device detects an alternating impedance of the oxygen concentration detecting device corresponding to each frequency by applying alternating voltages of a plurality of frequencies to the oxygen concentration detecting device and analyzing each of the alternating impedances detected by the impedance detecting means so as to calculate a parameter indicating a change in the characteristic of the oxygen concentration detecting device, and thereby achieve control of the air-fuel ratio sensor.

Abstract: The present invention is an engine control for an internal combustion engine having at least one combustion chamber and an air/fuel charging system for delivering an air and fuel charge to the combustion chamber for combustion therein. The control includes an oxygen sensor associated with the combustion chamber, the sensor providing feedback data based upon the air/fuel ratio of the charge supplied to the combustion chamber. The control also includes at least one sensor for sensing a condition other than the air/fuel ratio in the combustion chamber which affects the output of the oxygen sensor. The control adjusts the air/fuel ratio of the charge delivered to the combustion chamber towards a target value based upon the output of the oxygen sensor, the control arranged to adjust the target value based upon the output of the at least one sensor sensing an operating condition other than the air/fuel ratio.

Abstract: A method for utilizing a wide range oxygen sensor voltage output that is proportional to exhaust gas fuel air mixture to correct for variations in a flexible fueled vehicle's fuel alcohol content is provided for a vehicle not equipped with an alcohol sensor.

Abstract: An air-fuel ratio control system for an internal combustion includes an air-fuel ratio sensor arranged in the exhaust system, and an ECU which controls an amount of fuel to be supplied to the engine in a feedback manner based on an output from the air-fuel ratio sensor by using an adaptive controller of a recurrence formula type, such that the air-fuel ratio of an air-fuel mixture supplied to the engine becomes equal to a desired air-fuel ratio. Deterioration of a response characteristic of the air-fuel ratio sensor is detected based on at least one adaptive parameter used in the feedback control of the amount of fuel to be supplied to the engine.

Abstract: Several embodiments of feedback control systems for either two or four-cycle engines that employ sensors such as oxygen sensors. The systems include an arrangement wherein the sensor condition is determined by comparing the response time with a normal response time. If the time of response is outside of the normal range, compensation may be made so as to permit continued feedback control. Embodiments are also describe that adjust the maximum permissible injection amount and also revert to an open control if the deterioration is more any predetermined amount.

Abstract: There is provided an air-fuel ratio control system for an internal combustion. An air-fuel ratio sensor arranged in the exhaust system detects an air-fuel ratio of exhaust gases emitted from the engine. An amount of fuel to be supplied to the engine is controlled in response to the output from the air-fuel ratio sensor by using a controller of a recurrence formula type, such that an air-fuel ratio of a mixture supplied to the engine is converged to a desired air-fuel ratio, to thereby effect feedback control of the air-fuel ratio of the mixture. The desired air-fuel ratio is determined based on operating conditions of the engine. The desired air-fuel ratio is smoothed when the engine is in a predetermined operating condition. The feedback control of the air-fuel ratio is carried out by the use of the smoothed desired air-fuel ratio.

Abstract: In an air-fuel ratio control system for an internal combustion engine, a fuel injection amount to be injected from a fuel injector is set based on a monitored operating condition of the engine. The fuel injector injects a corresponding amount of fuel to the engine. An air-fuel ratio sensor monitors exhaust gas discharged from the engine and detects an air-fuel ratio. The system derives an injector sensitivity based on a current fuel injection amount and an output of the air-fuel ratio sensor and further derives, as an injector sensitivity deviation, a ratio between the derived injector sensitivity and an injector sensitivity estimated upon designing the system. The system further derives a sensitivity correction term based on the derived injector sensitivity deviation so as to correct the injector sensitivity. The system may also correct an air-fuel ratio sensor sensitivity in a similar manner.