Abstract: In a direct injection spark ignition engine which is operable in three operation modes including a stoichiometric air/fuel ratio operation mode, a pre-mixture combustion mode and a stratified combustion operation mode which are different in the desired air/fuel ratio and a single air/fuel ratio sensor installed downstream of the exhaust manifold, the sensor output is successively sampled and one from among the sampled data is selected based on the engine speed and engine load and selected one of the operation modes such that the air/fuel ratio at each cylinder can be accurately estimated for the selected operation mode under the engine operating conditions.

Abstract: A high efficiency compression ignition after-treatment system of a combustion engine includes a first combustion chamber adapted to reciprocatably receive a first piston assembly and a second combustion chamber adapted to reciprocatably receive a second piston assembly. A combustion exhaust passage is coupled between the first and the second combustion chambers. A fuel passage may be connected to the first combustion chamber, and a fuel passage connected to the second combustion chamber. A processed exhaust passage is coupled to the second combustion chamber for receiving the processed exhaust therethrough. A fuel injector is coupled to the second combustion chamber. A three-way catalyst has an inlet coupled to the processed exhaust passage and an outlet coupled to an exhaust passage. An exhaust gas oxygen sensor is connected to the processed exhaust passage. A fuel controller is coupled to the fuel injector and the exhaust gas oxygen sensor.

Abstract: In a method of operating an internal combustion engine which has at least two cylinder banks that can be controlled separately as a function of a desired load, wherein a desired pressure in the intake pipe of the internal combustion engine is determined and set by means of an air supply device for supplying combustion air to the cylinders of the internal combustion engine, at least one engine-related characteristic value which affects the behavior of the internal combustion engine is determined for each cylinder bank, and, in the event of a difference between the characteristic values of the cylinder banks, at least one cylinder bank is manipulated in such a way that the average value of the considered characteristic quantity corresponds to a desired average value in order to reduce the thermodynamic and mechanical loading of the internal combustion engine with bank-selective operating mode.

Abstract: An engine for a marine vehicle includes a controller having a predetermined map defining a relationship between a fuel injection parameter and an engine operation characteristic. Additionally, the controller includes at least one compensation factor for adjusting the fuel injection parameter. The compensation value is derived from data recorded during a test of the engine. The compensation factor is used during the normal operation of the engine to achieve a predetermined air/fuel ratio.

Abstract: A revolution number control system includes ignition timing delay controlling means for delaying ignition timing from the ignition advance amount n at first prescribed value n2 when the engine revolution number NE is between the first prescribed value n2 and a clutch-on revolution number n4. The first prescribed value n2 is a predetermined revolution number smaller than a present revolution number and the clutch-on revolution number n4 is the present revolution number, and the revolution number control system 40 controls the revolution number by operating the ignition timing delay controlling means when a throttle opening sensor does not detect a change in the throttle opening.

Abstract: A control system of an internal combustion engine is comprised of an operation angle adjustment mechanism which continuously varies an operation angle of intake valves of the engine, an air-fuel ratio detector which detects an exhaust parameter indicative of air-fuel ratio information, and a control unit which are coupled to the operation angle adjustment mechanism and the air-fuel ratio detector. The control unit feedback-controls an air-fuel ratio of the engine on the basis of the exhaust parameter and corrects the operation angle on the basis of the exhaust parameter.

Abstract: A system and method of controlling an engine includes sensing a concentration of NOx in exhaust gases produced by the engine and generating a sensed NOx value representative thereof, and controlling an engine control set point as a function of the sensed NOx value. The system also calculates a NOx difference value by subtracting a base NOx value from the sensed NOx value, and if an absolute value of the difference value exceeds a threshold, modifying the set point as a function of the NOx difference value. The method also includes sensing engine RPM, sensing engine manifold absolute pressure (MAP), determining the NOx value as a function of sensed engine RPM and MAP.

Abstract: In a method of operating an internal combustion engine which has at least two cylinder banks that can be controlled separately as a function of a desired load, wherein a desired pressure in the intake pipe of the internal combustion engine is determined and set by means of an air supply device for supplying combustion air to the cylinders of the internal combustion engine, at least one engine-related characteristic value which affects the behavior of the internal combustion engine is determined for each cylinder bank, and, in the event of a difference between the characteristic values of the cylinder banks, at least one cylinder bank is manipulated in such a way that the average value of the considered characteristic quantity corresponds to a desired average value in order to reduce the thermodynamic and mechanical loading of the internal combustion engine with bank-selective operating mode.

Abstract: An arrangement for utilizing a combustion sensor with an internal combustion engine. The arrangement includes a sensor mounted to the outside of an engine cylinder for communication with exhaust gasses within the cylinder via a sampling passage. A mounting structure holds the sensor proximate the sampling passage and forms a sensor chamber to receive exhaust gas therein. The sensor chamber includes a flow diverter to prevent remaining combustion particles and liquid droplets from lodging against the sensor. The chamber also includes a collection region for collecting the particles and liquid which can then be expunged through a drain outlet.

Abstract: An internal combustion engine that utilizes a control system for improving operation of the engine under a variety of conditions. The control system includes a sensor that directly senses a combustion condition in a cylinder. The output of the sensor is utilized in adjusting the air-fuel mixture delivered to other, non-sensed cylinders to optimize engine operation.

Abstract: A plurality of control object models set with different waste times, respectively, are provided, and each of the control object models is identified to compute a predicted output using the identified control object models. The predicted output and an actual output detected are compared with each other, to select the control object model in which a difference therebetween becomes minimum as a final control object model. Then, an input to the control object is feedback controlled, while estimating an output after the lapse of waste time using the selected control object model to compare the predicted output with the output detection value.

Abstract: The performance of a compression ignition internal combustion engine is improved by optimizing excess air ratio (lambda) and/or intake air charge temperature (ACT) on a full time, fall range basis. The basic procedure is to first determine the desired or optimum lambda and then to control ACT and intake manifold absolute pressure (MAP) to maintain them at the optimum values for the fuel quantity required at a particular operating point. This approach allows control of both temperature and pressure of the air entering the engine. Full range control requires that lambda and ACT be controlled both upward and downward to achieve optimal engine performance. Control of both lambda and ACT is further enhanced through the use of a supercharger with adjustable input power installed in series with a standard turbocharger compressor of the engine.

Abstract: A fuel metering method is described for setting a desired air-to-fuel ratio in the combustible mixture to a controlled auto-ignition engine in which intake air is admitted through a wide open throttle and controlled indirectly by varying the mass of residual gases in the combustion chamber at the instant when the intake valve opens by regulating the timing of the closing of the exhaust valve during the exhaust stroke.

Abstract: A method for controlling the titre of the exhaust gases in an internal combustion engine, in a control system comprising a control unit and oxygen sensor means, disposed along an exhaust duct of the engine and supplying a signal indicative of a titre of the exhaust gases; the control unit comprising a table, a controller and a correction and actuation block, the table receiving as input a plurality of engine-related parameters and an objective titre value and supplying as output a plurality of operating parameters; the controller receiving as input the operating parameters and the signal and supplying as output a correction parameter.

Abstract: A method of controlling an internal combustion engine includes determining the pressure within the cylinder with a pressure sensor which samples at specific positions of the piston indicating the properties of the thermodynamic cycle. The engine is controlled and operating condition diagnosed in real time based on that series of cylinder pressures at corresponding piston positions.

Abstract: The invention relates to a method for the diagnosis of a sensor in connection with control of a combustion engine. The method includes feeding fuel under pressure (p) to the engine, detecting the pressure (p) by means of the sensor, and controlling the air/fuel mixture based on to the operating state of the engine. The invention involves an intentional modification of both the pressure (p) and injection time period (tinj) during which fuel is fed to the engine. The modifications are selected in such a way that substantially no change in the fuel flow (F) to the engine is obtained. A check is performed to determine if the modifications of the pressure (p) and injection time period (tinj) result in any unallowable deviation in the operating state of the engine. If so, an indication that the sensor is defective is provided. With the invention, an improved diagnosis method for checking the functioning of a fuel pressure sensor is provided.

Abstract: In a direct injection spark ignition engine which is operable in three operation modes including a stoichiometric air/fuel ratio operation mode, a pre-mixture combustion mode and a stratified combustion operation mode which are different in the desired air/fuel ratio and a single air/fuel ratio sensor installed downstream of the exhaust manifold, the sensor output is successively sampled and one from among the sampled data is selected based on the engine speed and engine load and selected one of the operation modes such that the air/fuel ratio at each cylinder can be accurately estimated for the selected operation mode under the engine operating conditions.

Abstract: In a stoichiometric operation mode after a lean operation mode, a control unit sequentially generates data representing an estimated value of an output VO2/OUT of an O2 sensor after the dead time of an exhaust system, and at the same time generates a target air-fuel ratio KCMD for an exhaust gas upstream of a catalytic converter in order to converge the estimated value to a predetermined target value. The air-fuel ratio of the exhaust gas is controlled at the target air-fuel ratio KCMD. In the stoichiometric operation mode, the reduced state of NOx in the catalytic converter is recognized based on the estimated value of the output of the O2 sensor, and whether the stoichiometric operation mode is to switch to the lean operation mode or not is determined depending on the reduced state of NOx in the catalytic converter.

Abstract: A revolution number control system includes ignition timing delay controlling means for delaying ignition timing from the ignition advance amount n at a first prescribed value n2 when the engine revolution number NE is between the first prescribed value n2 and a clutch-on revolution number n4. The first prescribed value n2 is a predetermined revolution number smaller than a preset revolution number and the clutch-on revolution number n4 is the preset revolution number, and the revolution number control system 40 controls the revolution number by operating the ignition timing delay controlling means when a throttle opening sensor does not detect a change in the throttle opening.

Abstract: Programmable open and closed loop electronics for control of an internal combustion engine.

Abstract: An air-fuel ratio feedback control of an internal combustion engine is performed, by a sliding mode control, by computing an air-fuel ratio feedback control amount including a linear term and a nonlinear term, and at the time of when switching a target air-fuel ratio or at the time of when switching the operating condition, such as the cutting of purge, where the air-fuel ratio is changed, the nonlinear term is initialized to a predetermined value corresponding to the post-switched operating condition.

Abstract: The method of operating an internal combustion engine, especially of a motor vehicle, having a combustion chamber (4), which is operable in a plurality of combustion cycles, includes feeding an air mass (42) and a fuel mass (3) into the combustion chamber (4) in each combustion cycle; adjusting a mixture composition lambda (&lgr;) of the air mass to the fuel mass for one of the combustion cycles so that &lgr;>1; determining a residual air portion present in the combustion chamber (4) due to combustion occurring in the combustion chamber in the combustion cycle in which the mixture composition lambda (&lgr;) is greater than one; and reducing the air mass to be supplied to the combustion chamber (4) in another combustion cycle following the one combustion cycle in which &lgr;>1 by about the residual air portion found in the one combustion cycle.

Abstract: The performance of a compression ignition internal combustion engine is improved by optimizing excess air ratio (lambda) and/or intake air charge temperature (ACT) on a full time, full range basis. The basic procedure is to first determine the desired or optimum lambda and then to control ACT and intake manifold absolute pressure (MAP) to maintain them at the optimum values for the fuel quantity required at a particular operating point. This approach allows control of both temperature and pressure of the air entering the engine. Full range control requires that lambda and ACT be controlled both upward and downward to achieve optimal engine performance. Control of both lambda and ACT is further enhanced through the use of a supercharger with adjustable input power installed in series with a standard turbocharger compressor of the engine.

Abstract: A downstream exhaust system controller generates a target value for the output of an upstream O2 sensor disposed between first and second catalytic converters for converging the output of a downstream O2 sensor disposed downstream of the second catalytic converter to a target value while taking into account the dead time of a downstream exhaust system. An upstream exhaust system controller generates a target air-fuel ratio for an internal combustion engine for converging the output of the upstream O2 sensor to a target value while taking into account the dead time of an upstream exhaust system. A fuel processing controller controls the air-fuel ratio of the internal combustion engine at the target air-fuel ratio according to a feedback control process.

Abstract: The engine of the present invention has a plurality of cylinders that are divided into a first group and a second group. An air flow meter for detecting an amount of air supplied to the engine is provided downstream of an air cleaner in an intake system. A crank angle sensor for detecting a rotational speed of the engine is provided adjacent to a crank shaft. The amount of air distributed to the first group and the amount of air distributed to the second group are calculated based on the detected amount of air and the detected rotational speed of the engine. The amount of fuel injected into the first group and the amount of fuel injected into the second group are corrected according to the calculated amounts of air distributed to the first and second groups.

Abstract: When a pulse width limitation control is carried out, an air-fuel ratio feedback correction control such as O2 feedback or an A/F (air-fuel ratio) learning correction control is prohibited or limited. When the pulse width limitation control is carried out, various kinds of factors for carrying out a basic injection amount are made a prohibition condition or a limitation condition, and when other operation conditions arise, the operability is not damaged.

Abstract: A number of embodiments of feedback control systems for two-cycle, internal combustion engine management systems. Each embodiment employs an exhaust system sensor which senses the exhaust gases by drawing exhaust gases from the exhaust of the engine. In some instances this is done directly from the cylinder and in others it is done in the exhaust system. In each embodiment, the sensor is provided in an accumulator chamber so as to provide an accurate signal of instantaneous engine running conditions. The use of the accumulator chamber insures that the combustible gases will not be diluted with fresh air charge, but will be able to purge from cycle to cycle so as to provide cycle-by-cycle information. Various arrangements are provided for protecting the sensor element including serpentine flow paths, shields, the direction in which the exhaust gases are delivered, lubricant catalysts, conduit shape, sensor cooling and combinations of these features.

Abstract: A feed back control system and method for direct injected engines, particularly useful in marine applications to avoid excessive hunting due to the close proximity of the sensor to the fuel injector. Both injection initiation and duration are controlled under most operating conditions. However, under certain conditions such as when only small corrections in the air fuel ratio are required the control is initially maintained by adjusting the injection timing.

Abstract: A plant control system controls a plant modeled as a discrete-system model including an element relative to a response delay of the plant. The plant control system includes an actuator for generating an input to the plant, a first detector detecting an output from the plant, and a second detector for detecting the input to the plant which is generated by the actuator. An identifier identifies parameters to be established of the discrete-system model based on data representing an output of the first detector and data representing an output of the second detector. A manipulated variable determining unit determines a manipulated variable which determines the input to the plant to control operation of the actuator such that the output from the first detector will be equalized to a predetermined target value, according to a predetermining algorithm using the parameters of the discrete-system model which are identified by the identifier.

Abstract: A plant control system for controlling a plant includes an actuator for generating an input to the plant and a first detector for detecting an output from the plant. A manipulated variable determining unit determines a manipulated variable which determines the input to the plant according to a sliding mode control process such that an output from the first detector will be equalized to a predetermined target value. The manipulated variable determining unit determines the manipulated variable to converge a plurality of state quantities, which comprise differences between a plurality of present and previous time-series data of the output of the first detector and the target value, onto a balanced point on a hyperplane for the sliding mode control process, which is defined by a linear function having variables represented respectively by the state quantities.

Abstract: A plant control system controls a plant modeled as a discrete-system model including an element relative to a response delay of the plant and an element relative to a dead time of the plant. The plant control system includes an actuator for generating an input to the plant, a first detector for detecting an output from the plant, and a second detector for detecting the input to the plant. An estimator generates data representing an estimated value of an output of the first detector after the dead time, based on data representing the output of the first detector and data representing an output of the second detector. A manipulated variable determining unit determines a manipulated variable which determines the input to the plant, based on the estimated value, represented by the data generated by the estimator, of the output of the first detector after the dead time.

Abstract: A feed back control system and method for direct injected engines, particularly useful in marine applications to avoid excessive hunting due to the close proximity of the sensor to the fuel injector. Both injection initiation and duration are controlled. Under certain conditions such as lean burn, steady state and transition from rich to lean the control is initially of only one of these two factors. If the air fuel ratio is then still out of range, the other control is effected.

Abstract: The invention is directed to a method for monitoring the operation of a gas probe, such as a .lambda.-probe for an internal combustion engine. The .lambda.-probe has a probe ceramic (Nernst cell) and a probe heater. The internal resistance (x) of the probe ceramic is measured and a desired value (y) is determined in dependence upon the temperature of the gas to be detected and the heating power of the probe heater. The internal resistance (x) is then compared to the desired value (y) and, when the measured value of the internal resistance (x) exceeds the desired value (y), then a fault signal is generated and/or the fault signal is outputted and/or the fault signal is stored.

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 cylinder-by-cylinder air-fuel ratio-estimating system for an internal combustion engine includes an air-fuel ratio sensor arranged in the exhaust system of the engine. The air-fuel ratio of a mixture supplied to each of the cylinders of the engine is estimated based on an output from the air-fuel ratio sensor, by using an observer for observing the internal operative state of the exhaust system based on a model representative of the behavior of the exhaust system. The estimated air-fuel ratio of the mixture supplied to each of the cylinders is initialized to a value corresponding to the output from the air-fuel ratio sensor, depending upon operating conditions of the engine.

Abstract: An air-fuel ratio control system for an internal combustion engine includes an air-fuel ratio sensor for detecting the air-fuel ratio of exhaust gases from the engine. An ECU estimates the air-fuel ratio of a mixture supplied to each of the cylinders cylinder by cylinder in response to an output from the air-fuel ratio sensor, by using an observer based on a model representative of the behavior of the exhaust system. Cylinder-by-cylinder air-fuel ratio control amounts corresponding respectively to the cylinders are calculated for carrying out feedback control of the air-fuel ratio of the mixture such that each of the estimated air-fuel ratio is converged to a desired value.

Abstract: An engine control apparatus in which it is possible to suppress variation of the A/F ratio due to variation of the fuel pressure and for the A/F ratio to converge in a very short time when continuous variation of the increase and decrease of the fuel pressure based on an operation state is performed in the A/F ratio control of an engine. The engine control apparatus sets a target fuel pressure based on an operation state, detects fuel pressure and controls fuel pressure to the target fuel pressure. An integration component of the feedback coefficient of the A/F ratio is corrected when at least one of the target fuel pressure and the detected fuel pressure is varied. Fuel injection amount is calculated based on the detected amount of intake air, the target A/F ratio and the feedback coefficient of the A/F ratio.

Abstract: A feedback control system and method for operating an internal combustion engine to provide the desired air/fuel ratio under all running conditions. The feedback control operates to modify the fuel/air ratio from that achieved by a basic setting that is derived from parameters of engine performance so as to maintain the desired ratio. The feedback control adjusts the air/fuel ratio in two different modes. In a first lean-set mode, when the air/fuel ratio is indicated to be lean, the feedback control adjusts the air/fuel mixture in a first large step and then a number of smaller incremental steps. In a second normal-operational mode, when adjustments to the air/fuel ratio is indicated to be rich, the feedback control adjusts the air/fuel mixture in a first large and then several smaller incremental steps, these steps being larger and more closely spaced in time than their respective counterpart steps in the lean-set mode.

Abstract: An air-fuel control system for use with an internal combustion engine has a catalytic converter disposed in an exhaust system of the engine, for purifying an exhaust gas emitted from the engine, a first exhaust gas sensor in the exhaust system for detecting an air-fuel ratio of the exhaust gas upstream of the catalytic converter, a second exhaust gas sensor in the exhaust system for detecting the concentration of a component of the exhaust gas which has passed through the catalytic converter, downstream of the catalytic converter, and a correction quantity calculator for determining a correction quantity to correct an air-fuel ratio of the engine based on an output from the second exhaust gas sensor so as to equalize the concentration of the component of the exhaust gas downstream of the catalytic converter to a predetermined appropriate value.

Abstract: An engine combustion condition judging method for detecting a crank angle speed of a multiple cylinder engine, for judging a combustion condition of each of cylinders of the engine based on the detection of the crank angle speed, wherein the improvement includes the steps of setting a predetermined crank angle range selectively determined within a range between a crank angle at which a combustion substantially terminate in a given cylinder and another crank angle at which a combustion substantially start in the next cylinder for detecting a crank angle speed property, and judging the combustion condition based on said crank angle speed property within the predetermined crank angle range. The combustion condition can be obtained reliably so that an appropriate A/F control can be accomplished irrespective of the engine operating condition.

Abstract: A diagnostic for diagnosing fault conditions including leak and restriction conditions in a positive crankcase ventilation (PCV) system of an internal combustion engine in which temperature of intake air passed to the PCV system and temperature of exhaust gas exhausted from the PCV system are monitored under test conditions and a temperature change across the PCV system generated therefrom for comparison to an expected temperature change reference as a function of current engine operating conditions. A significant persistent deviation of the temperature change away from the expected temperature change is indicated as a fault condition of the PCV system.

Abstract: An evaporative fuel processing apparatus which can optimally process fuel gas according to navigation information or the like. This apparatus obtains future running information from a navigation system and further predicts an amount quantity of fuel vapor generated in a fuel tank (13) according to the running information. Further, the apparatus determines an amount of fuel vapor to be purged from a canister (14), namely, a valve opening of a purge control valve (142) so that an amount of fuel vapor adsorbed in the canister (14) is not more than a predetermined upper limit and that an amount of fuel adsorbed in the canister (14) after running is almost zero. Thus, an evaporation emission is reduced and the durability of the canister is prolonged by controlling the purge control valve.

Abstract: A fuel management system for a gaseous fuel internal combustion engine is disclosed in which a mass air flow sensor as well as a mass gas flow sensor provide input signals to an electronic control unit (ECU) which then determines the air/fuel ratio. The ECU in turn generates output signals to a fuel valve to control the mass of fuel flow to the engine and thus the air/fuel ratio. A turbocharger bypass valve, a precooler for the gaseous fuel supply, a pressure accumulator upstream from the fuel valve, as well as a system to calibrate the engine to the specific gaseous fuel is described to enhance the accuracy of the fuel management system. An improved pressure balanced valve for controlling the fuel flow to the engine is also provided as well as a cylinder pressure transducer to optionally provide an output signal to the ECU to determine the air/fuel ratio.

Abstract: A fuel metering control system for an internal combustion engine including a feedback loop having an adaptive controller and an adaptation mechanism that estimates a controller parameters .theta.. The adaptive controller corrects the quantity of fuel injection to bring a controlled variable obtained at least based on an output of said air/fuel ratio sensor, to a desired value. The air/fuel ratio sensor outputs are sampled and one of the sampled data is selected as the air/fuel ratio to be input to the adaptation mechanism. Similarly, the senor outputs are sampled and one of the sampled is selected in accordance with another characteristic to be used in the estimation of the air/fuel ratios of the individual cylinder. The air/fuel ratio is discriminated to be within a prescribed range, and set to a predetermined value when it is determined to be within the prescribed range.

Abstract: A target torque map is determined by an engine rotation number and an acceleration pedal opening degree. Plural control constant groups are provided to correspond the respective target torque map. A fuel precedent control is carried out by the plural constant control groups. By detecting an engine combustion condition, under a worse combustion condition a transfer to a higher torque side is carried out with a time function according to a complementary control of the control constant group. In a direct injection system engine, a controlling apparatus in which a stratified combustion and a homogeneous stoichiometric combustion are easily and stably.

Abstract: Fuel is pressurized by the expansion and contraction of a pump chamber defined inside a casing according to the rotation of a power input shaft which penetrates from the outside of the casing into its inside. A first seal member is provided between the casing and the power input shaft and prevents escape of fuel which is inside the casing, and a second seal member is provided in series therewith. Further, leakage of fuel to the outside of the casing from the second seal member is prevented by the provision of a drain conduit which drains fuel which has leaked into a space defined between the first seal member and the second seal member.

Abstract: Feedback control systems for engines employing combustion condition sensors. The feedback control is varied in response to various other parameters such as back pressure, engine speed, engine temperature, engine load and initial start-up operation so as to provide more accurate control under varying and transient conditions.

Abstract: A fuel vapor purge control system of an automobile engine comprises fuel vapor concentration calculating means for calculating a concentration of fuel vapor in the purge flow based on a feedback correction coefficient, target purge rate calculating means for selectively setting a target purge rate depending on the magnitude of the fuel vapor concentration, purge valve controlling means for controlling the operation of a purge control valve so as to obtain the target purge rate, purge condition judging means for judging whether or not a purge condition to perform purging is satisfied based on operational conditions of the engine, wherein the target purge rate calculating means sets an initial target purge rate after the purge condition judging means judges that the purge condition is satisfied, the initial target purge rate being gradually increased with an elapse of time from an initial rate to a predetermined rate, and then sets a target purge rate depending on the fuel vapor concentration after the initial

Abstract: A fuel metering control system for an internal combustion engine including a feedback loop having an adaptive controller and an adaptation mechanism that estimates a controller parameters .theta.. The adaptive controller corrects the quantity of fuel injection to bring a controlled variable obtained at least based on an output of said air/fuel ratio sensor, to a desired value. The adaptation mechanism is input with the controlled variable once per prescribed crank angle such as TDC of a certain cylinder and estimates the controller parameters (vector). The adaptive controller is therefore operated to synchronize with every prescribed crank angle, e.g., every TDC of all cylinders of the internal combustion engine. With the arrangement, the system enables adaptive control of a commercially practical internal combustion engine without degrading control performance.

Abstract: A fuel metering control system for an internal combustion engine including a feedback loop having an adaptive controller and an adaptation mechanism that estimates controller parameters .theta.. The adaptive controller corrects the quantity of fuel injection to bring a controlled variable obtained at least based on an output of said air/fuel ratio sensor, to a desired value. Estimation error of the controller parameters are defined by an error signal e*. The system is configured such that the signal is compared with a limit value and is replaced to a predetermined value when the calculated estimation error signal exceeds the limit value. Thus, the signal is determined to be a predetermined value.