Abstract: An air/fuel ratio feedback control system with the adaptive controller. The adaptive controller has a system parameter estimator which identifies system parameters such that the error between the desired value and the controlled variable outputted from the plant decreases to zero. In the system, a basic fuel injection amount is determined at a feedforward system. The adaptive controller is placed outside of the basic fuel injection amount determining system and receives the desired value (air/fuel ratio) and the controlled value (detected air/fuel ratio) using the system parameters etc. The calculated feedback coefficient is multiplied to the basic fuel injection amount to determine a final injection amount to be supplied to the plant (engine). Variables necessary for the system parameter calculation are limited their change of range so as to make the controller to be realized on a low performance computer with a small word length.

Abstract: A system for controlling fuel metering for a multi-cylinder internal combustion engine, having a feedback loop which has an adaptive controller and an adaptation mechanism coupled to the adaptive controller for estimating controller parameters .theta.. The adaptive controller calculates a feedback correction coefficient using internal variables that include the controller parameters .theta., to correct a basic quantity of fuel injection obtained by retrieving mapped data by engine speed and engine load, to bring a detected air/fuel ratio to a desired air/fuel ratio. In the system, the internal variables of the adaptive controller are determined in response to detected engine operating conditions, when the engine operation has shifted from an open-loop control region to the feedback control region.

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 having a plurality of cylinders. The system includes an air/fuel ratio sensor and engine operating condition detecting means for detecting engine operating conditions. The basic quantity of fuel injection is determined by retrieving mapped data according to the engine speed and engine load. A controller is provided to calculate a feedback correction coefficient to correct the quantity of basic fuel injection such that variance between individual cylinder air/fuel ratios is decreased. The quantity of fuel injection is further corrected by a fuel adhered to an intake manifold wall.

Abstract: A fuel metering control system for an internal combustion engine having a plurality of cylinders. The system includes an air/fuel ratio sensor and engine operating condition detecting means for detecting engine operating conditions at least including engine speed and engine load. The basic quantity of fuel injection is determined by retrieving mapped data according to the engine speed and engine load. An adaptive controller is provided to calculate a feedback correction coefficient to correct the quantity of basic fuel injection such that the detected air/fuel ratio is brought to a desired air/fuel ratio value is provided for calculating feedback correction coefficients to correct the quantity of fuel injection. The output quantity of fuel injection is determined on the basis of the basic quantity of fuel injection and the feedback correction coefficients, and in addition, fuel adhered on an intake manifold wall.

Abstract: A fuel metering control system for an internal combustion engine, having a feedback loop. In the system, the quantity of fuel injection (Tim) to be supplied to the engine (plant) is determined outside of the feedback loop. A feedback correction coefficient (KSTR) is calculated using an adaptive controller and a feedback control is carried out by multiplying the quantity of fuel injection by the coefficient in the feedback control region. In view of the situation, once leaving the feedback control region due to, for example, fuel cutoff, but soon returning to the feedback control region shortly, internal variables of the adaptive controller necessary for coefficient calculation are held so as to make it unnecessary to determine the variables and to keep the control continuity and to enhance the controllability. On the other hand, if it takes a longer time to return the region, the variables are set to initial values.

Abstract: A system for controlling fuel metering for a multi-cylinder internal combustion engine, having a feedback loop which has an adaptive controller and an adaptation mechanism coupled to the adaptive controller for estimating controller parameters .theta.. The adaptive controller calculates a feedback correction coefficient using internal variables that include at least said controller parameters .theta., to correct a basic quantity of fuel injection obtained by retrieving mapped data by engine speed and engine load, to bring a detected air/fuel ratio to a desired air/fuel ratio. In the system, the internal variables of the adaptive controller are set to predetermined values, when the supply of fuel is resumed after termination of the fuel cutoff, and the adaptive controller calculates the feedback correction coefficient based on the internal variables set to the predetermined value.

Abstract: A system for controlling fuel metering for a multi-cylinder internal combustion engine. In the system, a feedback loop having an adaptive controller and an adaptation mechanism coupled to the adaptive controller for estimating controller parameters .theta. is provided. The adaptive controller calculates a feedback correction coefficient using internal variables including the controller parameters .theta., to correct a quantity of fuel injection obtained by retrieving mapped data by engine speed and engine load, to bring a detected air/fuel ratio to a desired air/fuel ratio. The internal variables of the adaptive controller are set such that the feedback correction coefficient is 1.0 or thereabout, when the engine operation has shifted from an open-loop control region to the feedback control region.

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.

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. The convergence speed of the controller parameters is determined by a gain matrix that has non-diagonal and diagonal element. The system is configured that the controller parameters are determined without calculating the non-diagonal elements of the gain matrix, or without calculating using the non-diagonal elements of the gain matrix in the determination, decreasing calculation volume.

Abstract: A control system for an internal combustion engine has an air-fuel ratio sensor arranged in the exhaust system. An air-fuel ratio feedback control carried out based on an output from the air-fuel ratio sensor such that an air-fuel ratio of an air-fuel mixture supplied to the engine is converged to a desired air-fuel ratio is selected between a high-response feedback control using an adaptive controller of a recurrence formula type and a low-response feedback control with a lower response speed than a response speed of the high-response feedback control. Operating conditions of at least one of the engine and an automotive vehicle on which engine is installed are detected. It is determined whether or not the engine is in an unsteady operating condition in which combustion of the engine undergoes a variation, based on detected operating conditions of at least one of the engine and the vehicle.

Abstract: A control system for an internal combustion engine includes a canister for adsorbing evaporative fuel generated in the fuel tank, a purging passage extending between the canister and the intake system, for purging evaporative fuel into the intake system, and a purge control valve for controlling a flow rate of evaporative fuel to be supplied to the intake system through the purging passage. Various sensors detect operating conditions of the engine, and an ECU controls the purge control valve according to detected operating conditions. An amount of fuel to be supplied to the engine is feedback-controlled by calculating a feedback control amount, based on an output from an air-fuel ratio sensor arranged in the exhaust system by using a controller of a recurrence formula type, and the amount of fuel to be supplied to the engine is controlled based on the calculated feedback control amount, such that an air-fuel ratio of an air-fuel mixture supplied to the engine is converged to a desired 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 controller parameters .theta.. The adaptive controller calculates a feedback correction coefficient that corrects the quantity of fuel injection to bring a controlled variable obtained at least based on an output of an air/fuel ratio sensor, to a desired air/fuel ratio. The convergence speed of the controller parameters are determined by a gain matrix. The gain matrix is determined in response to at least one of the detected engine operating conditions.

Abstract: A fuel metering control system for an internal combustion engine including 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 at least obtained 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 a TDC of a certain cylinder of a four-cylinder engine and estimates the controller parameters (vector) such that the adaptive controller is operated to synchronize with every 4 prescribed crank angle such as every TDC of all cylinders of the internal combustion engine, or with every prescribed crank angle such as every TDC. 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, having a feedback loop. In the system, the quantity of fuel injection (Tim) to be supplied to the engine (plant) is determined outside of the feedback loop. A first feedback correction coefficient (KSTR) is calculated using an adaptive law, while a second feedback correction coefficient (KLAF(KSTRL)), whose control response is inferior to the first feedback correction coefficient is calculated, using a PID control law. The feedback correction coefficients are calculated such that the plant output (air/fuel ratio) is brought to a desired (desired air/fuel ratio). A Variable(s) of one coefficients is replaced with a value of the other coefficient such that the one coefficient becomes close to the other. Moreover, the second coefficient (KLAF(KSTRL) is used at a time of returning from open-loop to the feedback control.

Abstract: A fuel metering control system for an internal combustion engine, having a feedback loop. In the system, the quantity of fuel injection (Tim) to be supplied to the engine (plant) is determined outside of the feedback loop. A first feedback correction coefficient (KSTR) is calculated using an adaptive law, while a second feedback correction coefficient (KLAF(KSTRL)), whose control response is inferior to the first feedback correction coefficient is calculated using a PID control law. The feedback correction coefficients are calculated such that the plant output (air/fuel ratio) is brought to a desired value (desired air/fuel ratio). The engine is equipped with a variable valve timing mechanism which switches the valve timing between characteristics for low engine speed and those for high engine speed. If the characteristic for high engine speed is selected, the second feedback correction coefficient is used for fuel injection quantity correction.

Abstract: A system for controlling fuel metering in an internal combustion engine using a fluid dynamic model and the quantity of throttle-past air is determined therefrom. Based on the observation that the difference between the steady-state engine operating condition and the transient engine operating condition can be described as the difference in the effective throttle opening areas, the quantity of fuel injection is determined from the product of the ratio between the area and its first-order lag value and the quantity of fuel injection under the steady-state engine operating condition obtained by mapped data retrieval, and by subtracting the quantity of correction corresponding to the quantity of chamber-filling air. The effective throttle opening area's first order lag is calculated using a weight that varies with the engine speed, so that elongation or shortening of the TDC interval due to the decrease/increase of the engine speed will not affect the determination of the quantity of fuel injection.

Abstract: A system for controlling fuel metering in an internal combustion engine using a fluid dynamic model with the quantity of throttle-past air being determined therefrom. Based on the observation that the difference between the steady-state engine operating condition and the transient engine operating condition can be described as the difference in the effective throttle opening areas, the quantity of fuel injection is determined from the product of the ratio between the area and its first-order lag value and the quantity of fuel injection under the steady-state engine operating condition obtained by mapped data retrieval and by subtracting the quantity of correction corresponding to the quantity of chamber-filling air. A pseudo-manifold pressure is estimated and is used for calculating the effective throttle opening area and its first lag value. The pseudo-manifold pressure is corrected by atmospheric pressure, engine coolant water temperature, etc., so as to enhance estimation accuracy.

Abstract: An air-fuel ratio control system for an internal combustion engine having first and second catalytic converters arranged in the exhaust passage comprises first to third exhaust gas component concentration sensors arranged in the exhaust passage, the first one being arranged upstream of the first catalytic converter, the second one at a location intermediate between the first and second catalytic converters, and the third one downstream of the second catalytic converter. An ECU carries out feedback control of the air-fuel ratio of a mixture supplied to the engine to a desired air-fuel ratio in response to an output from the first exhaust gas component concentration sensor. A first feedback control parameter for use in the feedback control is calculated, based on an output from the second exhaust gas component concentration sensor.

Abstract: A system for estimating an exhaust gas recirculation rate for an internal combustion engine. In the system, the EGR rate when its operation is steady is first determined to a desired value with respect to the engine operating conditions at least including the engine speed and the engine load, then the EGR rate is estimated as;EGR rate=(steady-state EGR rate).times.{(gas flow rate QACT determined by the actual valve lifting amount and the ratio between the upstream pressure and the downstream pressure of valve)/(gas flow rate QCMD determined by a command value and the ratio between the upstream pressure and the downstream pressure of valve)} A delay time until the recycled gas enters the combustion chamber is determined and one from among the EGR rates or a fuel injection correction coefficients calculated therefrom consecutively is selected.