Abstract: A canister includes an adsorbent, an air layer and an air hole. An ECU obtains a physical status quantity Mgair representing the vapor stored state of the air layer, a physical status quantity Mgcan representing the fuel vapor stored state of the adsorbent, and a physical status quantity Fvptnk representing the vapor generating state in the fuel tank. The ECU then estimates a total vapor flow rate Fvpall purged to an intake system of the engine by using a physical model related to the vapor behaviors. The physical model is based on the obtained physical status quantities. The ECU corrects the fuel supply amount to the engine according to the estimated flow rate Fvpall. As a result, the air-fuel ratio feedback control is readily prevented from being influenced by the fuel vapor purging.

Abstract: A diesel-cycle engine with a unique exhaust gas recirculation system includes a plurality of cylinders with fuel feed for each of the cylinders and an intake manifold for distributing intake air to each of the cylinders for combustion of the fuel charges therein with generation of exhaust gas. The exhaust gas is discharged to ambient atmosphere through an exhaust line with a gas turbine therein. The gas turbine drives an intake compressor which serves to compress the intake air. An engine controller controls a valve regulating the amount of exhaust gas recirculation responsive to sensed concentration of an exhaust gas component. In another embodiment, an engine controller controls a valve regulating the amount of exhaust gas recirculation, responsive to sensed demand for torque and control of fuel injection quantity is responsive to sensed concentration of an exhaust gas component.

Abstract: Method for estimation of the quantity of fresh air present in the intake and exhaust manifolds of an internal combustion engine with a recirculation circuit, by an observer, applied to a system of the third order, which models the physical system constituted by the intake and exhaust manifolds; the system is obtained from differential equations, which regulate the processes of mixing of the gases, and from an equation which represents the behaviour of a lambda sensor.

Abstract: Correction of a fuel injection amount in an internal combustion engine during purge of evaporative fuel is performed on the basis of an output from an intake-oxygen concentration sensor disposed in an intake passage of the internal combustion engine. If the amplitude of fluctuations in engine speed becomes equal to or greater than a predetermined value, it is determined that there is an anomaly in engine output. In addition, if an anomaly in engine output is detected during purge and if no anomaly in engine output is detected during stoppage of purge, an ECU determines that an anomaly has occurred in the intake-oxygen concentration sensor, cancels correction of the fuel injection amount based on an output from the intake-oxygen concentration sensor during purge, and corrects the fuel injection amount on the basis of outputs from exhaust-gas air-fuel ratio sensors.

Abstract: In air-fuel ratio control apparatus and method for an internal combustion engine having an EGR valve interposed in an EGR passage between an intake manifold and an exhaust manifold, a target EGR quantity is calculated, a determination is made which of air-fuel ratio feedback controls through an EGR control and through an intake-air quantity is to be executed according to the target EGR quantity, and one of the air-fuel ratio feedback controls is selectively made according to a result of a determination of which of the air-fuel feedback controls is to be executed. During an execution of a rich spike control, the feedback control through the intake-air quantity control is unconditionally executed.

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 initializing to a predetermined value corresponding to the post-switched operating condition.

Abstract: Fuel vapor adsorbed by activated carbon 4a in a canister 4 is introduced to an engine 10 by a manifold vacuum in an intake air passage 8, and burnt. The controller 21 estimates the fuel amount desorbed from the canister 4 during purge, using a canister model (physical model) comprising an equation which computes the adsorption amount and an equation which computes the desorption amount from the adsorption amount and purge rate. An injection pulse width output to injectors 15 is corrected to reduce an air-fuel ratio fluctuation due to the supply of this desorbed fuel to the engine 10.

Abstract: A fuel vapor emission control device of an engine 10 includes a canister 4 which adsorbs fuel vapor generated in a fuel tank 1, and a purge valve 11 which opens and closes a pipe 6 connecting the canister 4 and an intake passage 8 of the engine 10. A controller 21 sets a target purge rate according to a difference between a target air-fuel ratio feedback deviation and an actual air-fuel ratio feedback deviation during purge, and drives the purge valve 11 so that the target purge rate is achieved.

Abstract: Based upon a purge air quantity supplied via a purge control valve to an intake system of an engine, an intake air amount into the engine, a fuel injection quantity into the engine, and an air-fuel ratio of the combustion mixture, a fuel vapor concentration is calculated as fuel vapor concentration=(intake air amount+purge air quantity air-fuel ratio×fuel injection quantity)/(the air-fuel ratio+1).

Abstract: A method of determining a purge fuel mass flow rate from a fuel vapor control system to an internal combustion engine having a compressor for delivering purge gas from the fuel vapor control system to the engine. The temperature rise of the purge gas passing through the compressor is determined. Then, a specific heat ratio of the purge gas is determined as the function of the temperature rise. The purge fuel mass flow rate is determined as a function of specific heat ratio of the purge gas.

Abstract: A control system for controlling the fueling of an engine assembly. The engine assembly includes an internal combustion engine, a fuel control system, a fuel vapor storage canister and a purge control system for purging the fuel vapor storage canister. The control system includes a purge fuel vapor measuring device for measuring an amount of purge fuel vapor flowing from the vapor storage canister to the internal combustion engine, a fuel corruption estimating device for estimating an amount of fuel corruption as a function of the amount of purge fuel vapor flowing from the vapor storage canister to the internal combustion engine and a controller for adapting the control of the internal combustion to the estimate of the amount of fuel corruption. A method for fueling an engine assembly having an internal combustion engine is also provided.

Abstract: This invention is a method and system for a hybrid electric vehicle adaptive fuel strategy to quickly mature an adaptive fuel table. The strategy adaptively alters the amount of fuel delivered to an internal combustion engine to optimize engine efficiency and emissions using engine sensors. Before the adaptive fuel strategy is permitted, an engine “on” idle arbitration logic requires the HEV to be in idle conditions, with normal battery state of charge, normal vacuum in the climate control and brake system reservoir; and, the vapor canister not needing purging. The strategy orders the engine throttle to sweep different airflow regions of the engine to adapt cells within the adaptive fuel table. In the preferred configuration, a generator attached to the vehicle drive train, adds and subtracts torque to maintain constant engine speed during the throttle sweeps.

Abstract: A purge control system of an engine has a purge valve which is opened and closed in accordance with the state of operation of the engine so as to establish a purge-on mode and a purge-off mode, thereby controlling purge rate which is the flow rate of the purge gas supplied to said engine. An air-fuel ratio feedback controller performs feedback control of the air-fuel ratio based on an output signal from an air-fuel ratio sensor and a purge density which is computed as the concentration of the evaporated fuel in the purge gas supplied to said engine. An air-fuel ratio correcting device performs, in the purge-on mode, a purge learning control having a plurality of cycles for learning the results of computations of the purge density and for effecting correction of the air-fuel ratio based on purge learned values obtained through the learning. The air-fuel ratio correcting device effects, in the purge-off mode, correction of the air-fuel ratio based on normal learned values learned in the purge-off mode.

Abstract: The control apparatus for an internal combustion engine of the present invention comprises: a fuel supply device for supplying fuel to the internal combustion engine; a fuel tank for retaining fuel; a purge device for purging fuel vapor, produced in the fuel tank, into an intake system of the internal combustion engine; a purge correction amount updating device for calculating a purge correction amount for correcting an amount of fuel to be supplied by the fuel supply device, depending on the amount of fuel vapor purged by the purge device; a target air-fuel ratio setting device for setting a target air-fuel ratio depending on a running state of the internal combustion engine; and an update amount setting device for updating the purge correction amount depending on the target air-fuel ratio set by the target air-fuel ratio setting device.

Abstract: An exhaust gas recirculation method and apparatus adapted for use on an internal combustion engine.

Abstract: In a direct injection spark ignition engine which is operable in lean-burn operation modes including a pre-mixture combustion mode and a stratified combustion operation mode and a stoichiometric air/fuel ratio operation mode, which are different in the desired air/fuel ratio. The degradation of combustion state is detected through misfire detection and if it is determined to be degraded, the desired air/fuel ratio, the EGR flow rate and the ignition timing are changed when the engine is operated in the stratified combustion operation mode, while the desired air/fuel ratio, the EGR flow rate and the purge flow rate are changed when the engine is operated in the pre-mixture combustion operation mode, thereby ensuring to suppress the combustion state degradation effectively.

Abstract: There are provided a control system and method and an engine control unit for an internal combustion engine, which are capable of properly determining an amount of fuel to be injected during a two-stage fuel injection combustion mode and a duration period of this mode such that stable combustion and smooth transition between combustion modes are ensured, thereby attaining excellent drivability and fuel economy. The combustion mode of the engine is switched between a homogeneous combustion mode in which fuel injection into each cylinder is performed during an intake stroke, a stratified combustion mode in which the fuel injection into the cylinder is performed during a compression stroke, and the two-stage fuel injection combustion mode in which the fuel injection into the cylinder is performed once during the intake stroke and once during the compression stroke during transition between the homogeneous combustion mode and the stratified combustion mode.

Abstract: In a control apparatus for use in an internal combustion engine which has an exhaust gas sensor adapted to detect exhaust gas components and provide an output deliver to an air-fuel ratio of mixture and which performs stratified charge combustion, signals for controlling the air-fuel ratio of mixture and the fuel injection timing are generated on the basis of the output of the exhaust gas sensor. When an optimal air-fuel ratio responsible for combustion stability is changed as a result of execution of EGR and evaporative fuel purging, a change of the air-fuel ratio is determined by using the output of the exhaust gas sensor. When the influence of the EGR or the evaporative fuel purging upon the air-fuel ratio is great, the air-fuel ratio is corrected and the fuel injection timing or the ignition timing is corrected.

Abstract: Evaporated fuel gas from a canister is introduced into an intake path of an internal combustion engine. A target air-fuel ratio is changed to a value on the fuel rich side during the introduction of purge gas in accordance with the purge gas concentration. This change will restrict the shift of the air-fuel ratio toward the lean side, allowing a catalyst to operate at high purification efficiency even during the introduction of purge gas. The change may be varied in accordance with the volume of the evaporated fuel gas or a ratio of the evaporated fuel gas to the fuel supplied to the engine.

Abstract: A method and apparatus for controlling the air-fuel ratio of an internal combustion engine that prevents erroneous learning while properly setting a learning frequency to thereby execute highly accurate air-fuel ratio control. Fuel vapor generated in a fuel tank is temporarily adsorbed in a canister via a tank inner pressure-regulating valve, and the adsorbed vapor is discharged to an engine intake system via a purge solenoid valve. A sensor for detecting tank inner pressure is arranged in the fuel tank, and an ECU calculates a feedback correction amount based on an oxygen concentration in exhaust gas and executes air-fuel ratio feedback control by using the feedback correction amount. The ECU prohibits the air-fuel ratio learning value from being updated when the tank inner pressure exceeds a predetermined criterion value based on the tank inner pressure detected by the tank inner pressure sensor.

Abstract: A fuel control system that estimates the fuel quantity received from purging of an evaporative emission control system and then accounts for the purge fuel in determining the amount of fuel to be injected into a cylinder of an internal combustion engine. Purge fuel quantity is represented by a purge equivalence ratio which is computed based upon an estimate of the hydrocarbon concentration in the purge gas. The hydrocarbon concentration is adaptively learned using an iterative routine that updates the estimate based on the integrated error between the actual and desired air/fuel ratios. Wall wetting and closed loop corrections are applied only to the non-purge fuel portion of the total fuel delivered to the engine cylinder. The closed loop control includes a block learn memory that provides a correction to the factory fuel calibration.

Abstract: An air-fuel ratio control apparatus of an internal combustion engine is provided which enables highly accurate calibration of an air-fuel feedback correction value to be completed in a short time, thus avoiding adverse influences on the emissions. The engine load is fixed when the air-fuel ratio or purge concentration is calibrated from the behavior of the air-fuel ratio feedback correction value. Thus, no change is observed in the engine load even if the driver operates the accelerator pedal to adjust the accelerator pedal position so as to change the required torque, and the air-fuel ratio of the air-fuel mixture is stabilized. Accordingly, air-fuel ratio calibration or purge concentration calibration can be promptly accomplished with high accuracy. Furthermore, while the engine load is being adjusted, the output torque is controlled in accordance with the required torque by adjusting the ignition timing.

Abstract: A diesel-cycle engine with a unique exhaust gas recirculation system includes a plurality of cylinders with fuel feed for each of the cylinders and an intake manifold for distributing intake air to each of the cylinders for combustion of the fuel charges therein with generation of exhaust gas. The exhaust gas is discharged to ambient atmosphere through an exhaust line with a gas turbine therein. The gas turbine drives an intake compressor which serves to compress the intake air. An engine controller controls a valve regulating the amount of exhaust gas recirculation responsive to sensed concentration of an exhaust gas component. In another embodiment, an engine controller controls a valve regulating the amount of exhaust gas recirculation, responsive to sensed demand for torque and control of fuel injection quantity is responsive to sensed concentration of an exhaust gas component.

Abstract: Purge control valves are mounted to purge pipings arranged in parallel for supplying purge gas from a canister to an engine. A flow rate of the purge control valve having a larger flow rate size is controlled in a step mode, and a flow rate equal to or smaller than a variation quantity in said step mode is controlled by the purge control valve having a smaller flow rate size.

Abstract: A fuel vapor feed controlling apparatus of a lean burn internal combustion engine suppresses either one of a rich misfire or a surge when fuel vapor is fed into the engine. A purge controlling unit controls an amount of fuel vapor fed from a fuel reservoir to the engine in response to an operational condition of the engine. A first compensation unit compensates the amount of fuel vapor such that an engine revolution speed of the engine may be identical with a target revolution speed. The purge controlling unit performs a purge control based on a compensation value compensated by the first compensation unit.

Abstract: A method is provided for accommodating the purge vapors from an evaporative emission control system of an automotive vehicle. The method includes a purge compensation model to identify the concentration of purge vapor entering the intake manifold of the engine of the automotive vehicle, identifying the source of the vapor as from the vapor collection canister or the fuel tank using a characteristic mapping of maximum concentration as a function of instantaneous flow and accumulated flow through a canister and uses this information to predict variations in vapor concentrations as a function of purge flow. The method also includes a purge control model which uses mode logic to identify an appropriate time to initiate a purge cycle, provides the flow conditions necessary for a learning portion of the purge compensation model and increases purge flow rates after the learning is complete to deplete the contents of the canister.

Abstract: Process for controlling an internal combustion engine equipped with an exhaust gas recirculation device (5) comprising a recirculation valve (51) and a device for regulating an air/fuel mixture injected into an inlet circuit as a function of the signal (LAM_AV) of an oxygen probe (41) placed in the exhaust circuit (4), characterized in that the controls of the valve (EGR_CTRL) are synchronized with at least one transition of a correction (LAM_COR) of the richness of the mixture in order to reduce the transient pollution peaks generated by the operating of the exhaust gas recirculation valve (51).

Abstract: The invention is directed to a method for operating an internal combustion engine such as for a motor vehicle. Regeneration gas is added for only a short time duration (T) to air inducted into the combustion chamber of the engine and fuel is injected directly into the combustion chamber. The fuel and regeneration gas are combusted in the combustion chamber and a specific behavior of the combustion of the fuel and the regeneration gas is assumed. The actual combustion behavior of the fuel and the regeneration gas is detected and the hydrocarbon concentration of the regeneration gas is determined from the assumed specific behavior and the detected behavior. Fuel is injected into the combustion chamber during the next time duration (T) for an injection time (TI) dependent upon the hydrocarbon concentration.

Abstract: The control apparatus for an internal combustion engine of the present invention comprises: a fuel supply device for supplying fuel to the internal combustion engine; a fuel tank for retaining fuel; a purge device for purging fuel vapor, produced in the fuel tank, into an intake system of the internal combustion engine; a purge correction amount updating device for calculating a purge correction amount for correcting an amount of fuel to be supplied by the fuel supply device, depending on the amount of fuel vapor purged by the purge device; a target air-fuel ratio setting device for setting a target air-fuel ratio depending on a running state of the internal combustion engine; and an update amount setting device for updating the purge correction amount depending on the target air-fuel ratio set by the target air-fuel ratio setting device.

Abstract: A fuel control system is provided for enhancing the fueling strategy of a vehicle at start up when fueling is being supplemented with purge vapors from the fuel tank. The system includes monitoring the purge vapor flow rate from the purge vapor control system to the engine at start-up. A dynamic crankshaft fuel control fuel multiplier is then calculated based on engine roughness. If the engine is operating rough during purge vapor fueling, the amount of injected fuel is adjusted according to the fuel multiplier. Once oxygen sensor feedback is available, the dynamic crankshaft fuel control fuel multiplier is recalculated based on the oxygen sensor goal voltage. If necessary, the amount of injected fuel may be readjusted with the updated fuel multiplier. Once the engine is warm, the purge vapor fueling stops and the present methodology ends.

Abstract: An apparatus for controlling air-fuel ratio in an engine provided with a fuel vapor purging system. The purging system sends the fuel vapor in a fuel tank to an intake passage. The actual air-fuel ratio is computed from the oxygen concentration of the exhaust gas. An electronic control unit (ECU) adjusts the amount of fuel injected from an injector. The ECU sets a feedback correction coefficient FAF to correct the difference between the actual air-fuel ratio and a predetermined target air-fuel ratio. The feedback correction coefficient FAF is feedback controlled. The ECU further considers fluctuations of the air-fuel ratio caused by the purging system in accordance with the operating state and operating history of the engine.

Abstract: An air-fuel ratio control apparatus adapted for an internal combustion engine equipped with a purge system. The air-fuel ratio control apparatus estimates the amount of fuel vapor present in a fuel tank from a balance between an estimated produced vapor amount and an estimated purged amount of fuel vapor. When the estimated amount of fuel vapor present is small, the concentration of fuel vapor to be purged is low, so that a base air-fuel ratio feedback coefficient is learned in a period where the estimated value is small. As a result, the base air-fuel ratio feedback coefficient is appropriate learned. Even if the base air-fuel ratio feedback coefficient is learned incorrectly, the air-fuel ratio control apparatus can correct the feedback coefficient. Accordingly, the concentration of the fuel vapor to be purged into the intake air can be detected accurately, thus permitting the base air-fuel ratio feedback coefficient to be maintained at a more appropriate value.

Abstract: A control system for a cylinder injection type internal combustion engine is capable of realizing improvement of the combustion state and reduction of harmful components contained in an exhaust gas by enhancing an air-fuel ratio control accuracy in EGR control. The system includes an air flow sensor for detecting a quantity of intake air, an air-fuel ratio sensor for detecting an air-fuel ratio of exhaust gas, means for controlling exhaust gas recirculation quantity to a desired exhaust gas recirculation quantity by means of an exhaust gas recirculation regulating means, and means for setting a fuel injection quantity of the fuel injection valve in dependence on a controlled desired air-fuel ratio within engine cylinder, intake air quantity and injection mode being validated. The exhaust gas recirculation quantity control means performs a feedback control on the exhaust gas recirculation quantity so that the air-fuel ratio of the exhaust gas coincides with the desired exhaust gas air-fuel ratio.

Abstract: A fuel vapor purging method controls fuel vapor purging during stratified operation. Several factors influence vapor purge control, including fuel vapor concentration in the cylinder and temperature of the emission control device. The fuel vapor passes through the cylinder unburned by maintaining the concentration within allowable limits. The unburned fuel vapor reacts exothermically in the emission control device thereby generating heat. To guarantee that the fuel vapor reacts in the first emission control device, the fuel vapor purge is restricted to a certain temperature range. To guarantee that the fuel vapor does not burn in the cylinder, the concentration is kept to a restricted value.

Abstract: An air-fuel ratio control apparatus for an internal combustion engine calculates a purge rate from a purge amount and an engine operating state, calculates a purge air density from the purge rate and an air-fuel ratio correcting coefficient, and calculates a purge air density correcting coefficient based on the purge rate and the purge air density. Further, the air-fuel ratio control apparatus calculates a learned air-fuel ratio feedback correction value from the air-fuel ratio feedback correcting coefficient, calculates a fuel injection amount based on the air-fuel ratio feedback correcting coefficient, the learned air-fuel ratio feedback correction value and the purge air density correcting coefficient, and alternately switches over the learning of the air-fuel ratio feedback correction and the learning of the purge air density.

Abstract: A system for purifying exhaust gas of an internal combustion engine having a catalyst in an exhaust system of the engine, said catalyst reducing nitrogen oxide when exhaust gas generated by the engine is in an oxidizing state. An EGR mechanism is provided for recirculating a part of the exhaust gas to an intake system of the engine, and is controlled such that a ratio of unsaturated and/or aromatic hydrocarbon concentration to nitrogen oxide concentration in the exhaust gas is at or above a predetermined value. The EGR mechanism is further controlled such that oxygen concentration in the exhaust gas is below a prescribed value. An injection timing mechanism is controlled for the same purpose. With this arrangement, the system improves the NOx purification rate of the catalyst.

Abstract: A control apparatus for an engine includes a burn mode determining unit for determining a stoichiometric burn mode or a lean burn mode, and a stratified charge burn mode or a homogeneous charge burn mode. A target A/F calculating unit calculates a target A/F according to the operational point of the engine and a phase lag filter changes the phase of said calculated target A/F. A first target A/F modifying unit modifies the target A/F whose phase is delayed, so that an unstable burn region is avoided and a second target A/F modifying unit further modifies the modified target A/F during a transitional period when the operation is switched so as to avoid the unstable region. A target A/F selecting unit selects one of the modified A/F modified by the first target A/F modifying unit and the target A/F modified by the second A/F modifying unit.

Abstract: A method is provided for accommodating the purge vapors from an evaporative emission control system of an automotive vehicle. The method includes a means of learning the flow rate of purge vapors from the fuel tank. The fuel tank model uses the output of a strategic adaption routine to learn the tank vapor flow rate. This flow rate is used to maintain fuel to air control under varying air flow and purge flow conditions especially under return-to-idle situations. As such, the fuel to air ratio at the injectors can be controlled under varying air flow and purge flow conditions to improve drivability and emissions.

Abstract: A fuel vapor concentration detecting apparatus in a lean-burn internal combustion engine detects a fuel vapor concentration and executes purge control. The apparatus includes an output fluctuation detecting module for detecting, on such an occasion that the fuel vapor is purged into an intake system of the internal combustion engine, an output fluctuation just when the fuel vapor is purged, and a concentration detecting module for calculating the fuel vapor concentration in accordance with a magnitude of the output fluctuation detected by the output fluctuation detecting module. The fuel vapor concentration in the lean-burn internal combustion engine is thus detected. A purge quantity or a state of the fuel injection is changed corresponding to the detected concentration of the fuel vapor.

Abstract: The invention is directed to a method for operating an internal combustion engine such as for a motor vehicle. Regeneration gas is added for only a short time duration (T) to air inducted into the combustion chamber of the engine and fuel is injected directly into the combustion chamber. The fuel and regeneration gas are combusted in the combustion chamber and a specific behavior of the combustion of the fuel and the regeneration gas is assumed. The actual combustion behavior of the fuel and the regeneration gas is detected and the hydrocarbon concentration of the regeneration gas is determined from the assumed specific behavior and the detected behavior. Fuel is injected into the combustion chamber during the next time duration (T) for an injection time (TI) dependent upon the hydrocarbon concentration.

Abstract: A system that performs a highly precise air-fuel ratio control by considering the effect of purge. During an air-fuel ratio feedback operation, an amount of purge control AFPRG is calculated according to the following equation by the use of an actual TAU (actual amount of fuel injection) (step 602).AFPRG=actual TAU/(TP.times.FTHA.times.FPA)-(FTC+FPRG+FLAF)where TP represents a basic amount of injection, FTHA represents a suction air temperature correction factor, FPA represents an atmospheric pressure correction factor, FTC represents an acceleration/deceleration correction factor, FPRG represents a purge correction factor, and FLAF represents an air-fuel ratio learning correction factor.

Abstract: A method for operating a multicylinder internal combustion engine with at least one adsorber catalytic converter in the exhaust line of the internal combustion engine includes operating the adsorber catalytic converter with periodically alternating adsorption and desorption operation. The exhaust leaving the adsorber catalytic converter in desorption operation is recycled and/or an oxidation catalytic converter is provided upstream of the adsorber catalytic converter. Exhaust recycling takes place occurs selectively in only one set of the cylinders of the internal combustion engine and this set of cylinders is operated in a state of incomplete combustion during desorption operation. Rich afterburning may be performed during desorption operation of the adsorber catalytic converter in the oxidation catalytic converter connected upstream and the oxidation catalytic converter is operated at an increased temperature during short regeneration phases to remove soot.

Abstract: In a, so-called, lean burn engine having a vaporized fuel processor, a concentration of a vaporized fuel purged into an intake air passage (so-called, a purge concentration) is estimated using a normal type oxygen concentration sensor. Whenever a predetermined interval of time has passed, the engine combustion condition is forcefully and temporarily transferred into a stoichiometric air-fuel mixture ratio combustion condition during which the purge concentration is estimated on the basis of an output signal from the oxygen concentration sensor during an air-fuel mixture ratio feedback control.

Abstract: A system for controlling an air/fuel ratio of an internal combustion engine, including a feedback control loop having an adaptive controller (STR controller) that receives as inputs a desired value r and a controlled variable y output from the plant (engine) and an adaptation mechanism that estimates adaptive parameters. The STR controller calculates a feedback correction coefficient KSTR, as an output u based upon at least the adaptive parameters, for correcting a basic amount of fuel supply calculated by retrieving mapped data, prepared beforehand, such that the controlled variable y converges to the desired value r. The system is configured such that the controlled variable y is determined based upon the detected air/fuel ratio KACT and a desired air/fuel ratio KCMD so that the desired value r is a predetermined value. More specifically, the controlled variable is determined to be a ratio between the detected air/fuel ratio and the desired air/fuel ratio such that the desired value r is 1.0 or thereabout.

Abstract: A method is provided for accommodating the purge vapors from an evaporative emission control system of an automotive vehicle. The method includes a means of learning changes in the mass of a purge vapor collection canister such that a mass of purge vapor in the canister can be determined. The canister model uses the output of a strategic adaption routine to learn the loading of the canister. Thereafter, the canister model uses the learned loading of the canister and tank flow rate from a tank model to compute the mass balance of purge vapor exiting and entering the canister. The concentration level is compared to the calibrated maximum in an open loop surface to determine the level of canister loading. Based on the current loading of the canister, the open loop surface of canister concentration as a function of flow rate and accumulated flow is used to predict how the concentration will change as the flow rate through the canister changes.

Abstract: An abnormality-diagnosing device for an evaporation purge system and an air-fuel ratio controller for an internal combustion engine having the abnormality-diagnosing device incorporated therein, which device can: prevent misdiagnosis as abnormal, which otherwise would occur under the influence of evaporative fuel caused by altitude, or change or swinging of fuel level or fuel; prevent deviation of an air-fuel ratio from a target value during purging of the evaporative fuel, which otherwise would occur under influence of the evaporative fuel resulting from altitude or fuel level; and, prevent deviation of the air-fuel ratio from the target value when the purge valve is opened, whereby a failure in drivability or aggravation of harmful exhaust component values can be prevented when the evaporative fuel is purged.

Abstract: A fuel vapor feed controlling apparatus of a lean burn internal combustion engine suppresses either one of a rich misfire or a surge when fuel vapor is fed into the engine. A purge controlling unit controls an amount of fuel vapor fed from a fuel reservoir to the engine in response to an operational condition of the engine. A first compensation unit compensates the amount of fuel vapor such that an engine revolution speed of the engine may be identical with a target revolution speed. The purge controlling unit performs a purge control based on a compensation value compensated by the first compensation unit.

Abstract: An air/fuel ratio controller for an internal combustion engine that obtains stabilized air-fuel ratio controllability even when an air-fuel ratio is changed during purge execution. In purge control to discharge fuel vapor adsorbed in a canister to an intake-air side of an internal combustion engine, the controller controls a purge ratio, by controlling operation of the purge solenoid valve, even when an air-fuel ratio is changed. A fuel-injection quantity from an injector is then compensated in correspondence thereto. Thus, stabilized air-fuel ratio controllability can be obtained by correction with a fuel-injection quantity, or purge correction by a control duty of the purge solenoid valve as a purge control parameter, even when an air-fuel ratio .lambda. is changed during purge execution, taking a predetermined ratio as the purge ratio.

Abstract: In an engine comprising a fuel vapor purge mechanism which mixes fuel vapor from a fuel tank with the intake air of the engine after fuel vapor has been adsorbed by a canister, a uniform fuel-air mixture and a stratified fuel-air mixture are selectively produced. When the engine is running with a stratified fuel-air mixture, purge of fuel vapor is prohibited. On the other hand, when the fuel vapor adsorption amount in the canister has reached a predetermined value, the engine is forcibly run with a uniform fuel-air mixture and purge of fuel vapor is performed, In this way, the fuel vapor adsorption amount in the canister is prevented from becoming excessive.

Abstract: An evaporated fuel treatment device comprising a purge control valve arranged between a canister and an intake passage of an engine. A drive pulse of the purge control valve is controlled by a duty ratio. When the engine operating state is one in which a large amount of evaporated fuel is produced in the fuel tank, the feedback correction coefficient is maintained at a is position deviated from the reference value so as to enable the feedback correction coefficient to change in accordance with the fluctuations of the air-fuel ratio.