Abstract: A method of determining a mass of fuel to be introduced into a suction pipe or into a cylinder of an internal combustion engine precontrols a basic injection time constituting a basic injection quantity, through a prescription of a lambda set point. The lambda set point is determined by a coordinated calculation through selecting a minimum and a maximum from a multiplicity of different lambda requirements which are derived from operating states of the internal combustion engine. Different priorities are allocated to the various lambda requirements.

Abstract: A method and system for adaptive transient fuel compensation in a cylinder of a multi-cylinder engine estimates fuel puddle dynamics for the cylinder by determining parameters of a wall-wetting model every engine cycle of the multi-cylinder engine. Fuel delivery to the cylinder is adjusted dependent on the estimated fuel puddle dynamics.

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, at a confluent portion of the exhaust system. 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. A gain for use in the estimation of the air-fuel ratio of the mixture supplied to each of the cylinders is estimated by the observer according to operating conditions of the engine.

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, at a confluent portion of the exhaust system. The air-fuel ratio of a mixture supplied to each of the cylinders is estimated based the 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 air-fuel ratio at the confluent portion is estimated by using a delay parameter representative of the response delay of the air-fuel ratio sensor, and the air-fuel ratio of the mixture supplied to each of the cylinders is estimated by using the estimated air-fuel ratio at the confluent portion. The estimated air-fuel ratio of the mixture supplied to each of the cylinders is subsequently used for estimating a value of the air-fuel ratio at the confluent portion of the exhaust system.

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 first feedback correction coefficient to correct the quantity of basic fuel injection such that the detected air/fuel ratio is brought to a desired value, and second feedback loop is provided for calculating feedback correction coefficients to correct the quantity of fuel injection. The desired air/fuel ratio is corrected by a second air/fuel ratio installed downstream of a catalytic converter.

Abstract: There is provided an air-fuel ratio control system for an internal combustion engine installed on an automotive vehicle. The control system controls the air-fuel ratio of a mixture supplied to the engine to a value leaner than a stoichiometric air-fuel ratio immediately after the start of the engine. Operating conditions of the engine and/or operating conditions of the automotive vehicle is detected. Starting of the vehicle is predicted based on the detected operating conditions of the engine and/or the detected operating conditions of the automotive vehicle. The air-fuel ratio of the mixture supplied to the engine is changed to a richer value than the leaner value when the starting of the vehicle is predicted.

Abstract: A control system for a multiple cylinder engine includes a vapor fuel introduction system for introducing a vapor fuel vaporized in a fuel tank. A feedback device is used for setting an air fuel ratio feedback compensation value for each of the cylinders or each group of cylinders of the engine and for executing an air fuel ratio feedback control. A fuel supply device is used for supplying engine fuel for each cylinder so as to equalize the air fuel ratio feedback compensation values of each of the cylinders or each group of the cylinders regardless of a change of an operating condition of a vapor fuel introduction control. A desirable A/F feedback control can be accomplished regardless of the execution of the vapor fuel purge in the multiple cylinder engine.

Abstract: A system for controlling fuel metering for an internal combustion engine provided with a first feedback loop that calculates a first feedback correction coefficient using an adaptive control law to correct a quantity of fuel injection such that a detected air/fuel ratio is brought to a desired air/fuel ratio, a second feedback loop that calculates a second coefficient using a PID control law to similarly correct the quantity of fuel injection, and a third feedback loop that calculates a third coefficient using a PID controller to correct the quantity of fuel injection such that air/fuel ratio variance among the cylinders decreases. Either of the first or second coefficient is selected and based on the selected coefficient, the feedback gains of the third feedback loop are determined.

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 said 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 to bring a detected air/fuel ratio to a desired air/fuel ratio determined earlier from the detected air/fuel ratio by a dead time d'. The dead time d' is properly determined to be corresponding to a time k at which the air/fuel ratio is detected. Alternatively, the dead time may be determined to be longer than the proper value to eventually improve vehicle drivability, or determined to be shorter than the proper value to compensate for insufficient fuel adhesion correction.

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 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 first 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, and second and third feedback loops are 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.

Abstract: An air-fuel ratio control system for an internal combustion engine has an air-fuel ratio sensor arranged in an exhaust passage of the engine for detecting an air-fuel ratio of exhaust gases emitted from a plurality of cylinders. An output from the air-fuel ratio sensor is sampled whenever the engine rotates through a predetermined crank angle, and sampled values of the output from the air-fuel ratio sensor are sequentially stored. An output characteristic of the air-fuel ratio sensor is detected. One of the sampled values of the output from the air-fuel ratio sensor is selected at least depending on the output characteristic of the air-fuel ratio sensor. An air-fuel ratio of a mixture supplied to each of the cylinders is estimated, separately from other ones of the cylinders, based on selected ones of the sampled values of the output from the air-fuel ratio sensor and a model representative of a behavior of the exhaust passage.

Abstract: An air-fuel ratio control system for an internal combustion engine includes an air-fuel ratio sensor provided at a collecting portion of an exhaust manifold. The air-fuel ratio sensor monitors an exhaust gas and changes its output in a linear fashion relative to an air-fuel ratio represented by the exhaust gas. The air-fuel ratio sensor is arranged at a position such that, after the number of strokes, corresponding to a multiple of the number of all cylinders, from a fuel injection for each cylinder, the air-fuel ratio sensor can measure an air-fuel ratio caused by the corresponding fuel injection. The system stores a target fuel amount for each of the cylinders. The system derives a feedback correction value depending on a deviation between a fuel amount introduced into the corresponding cylinder, which is derived based on the air-fuel ratio monitored by the air-fuel ratio sensor, and the stored number-of-stroke prior target fuel amount.

Abstract: In a multi-cylinder engine, amounts of fuel injection supplied to respective cylinders are individually corrected on the basis of a signal from A/F sensors in the number less than the number of cylinders of the engine, for example, one A/F sensor, so that the air/fuel ratios for respective cylinders are feedback-controlled at a substantially uniform predetermined air/fuel ratio. Therefore, it is possible to perform precise air/fuel ratio control so as to accurately maintain the air/fuel ratio of the engine at the stoichiometric air/fuel ratio, to reduce the concentrations of HC, CO, and NOx in exhaust gas.

Abstract: A control system and method for a multi cylinder engine that employs a single sensor associated with only one of the combustion chambers for feedback control of that combustion chamber and for controlling the fuel/air ratio of the remaining combustion chambers. The control of the remaining combustion chambers is based upon the value of the feedback control upon the time of shifting between lean and rich mixtures. The reference value is selected, however, after the initial switch between rich and lean so as to permit time for stabilization.

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 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: Internal combustion engine air/fuel ratio control provides for individual engine cylinder air/fuel ratio balancing through sensing of individual cylinder air/fuel ratio and through comparison of sensed individual cylinder air/fuel ratio to a target air/fuel ratio with air/fuel ratio control command correction prescribed on a cylinder-by-cylinder basis. The target air/fuel ratio may be determined as an overall average cylinder actual air/fuel ratio. An additional control loop is provided for driving a value representing overall engine air/fuel ratio toward a desired air/fuel ratio, such as the stoichiometric ratio. Correction values are learned gradually for each engine cylinder and stored and recalled as a function of an engine operating level.

Abstract: A method and system for adaptive transient fuel compensation in a cylinder of a multi-cylinder engine estimates fuel puddle dynamics for the cylinder by determining parameters of a wall-wetting model every engine cycle of the multi-cylinder engine. Fuel delivery to the cylinder is adjusted dependent on the estimated fuel puddle dynamics.

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: An engine air-fuel ratio control system for a multi-cylinder engine that employs a fuel-air ratio sensor which is associated with only one cylinder. The other cylinders are operated leaner than that with which the sensor is associated. Also, the system can operate on an open control, and when switching from open control to feedback control, the incremental adjustments in fuel amount are initially made smaller and for a longer time period so as to reduce overshooting and hunting while permitting quick recovery during subsequent feedback control operation.

Abstract: A fuel injection apparatus for internal combustion engine of this invention applies detection output of a wide-range air/fuel ratio sensor to an observer so as to estimate an air/fuel ratio of individual cylinder and, based on thus estimated air/fuel ratio, obtains an air/fuel ratio correction coefficient for individual cylinder and correctively controls the fuel injection amount for individual cylinder with the air/fuel ratio correction coefficient for individual cylinder. While the estimation processing of the observer is always continued, the air/fuel ratio correction coefficient for individual cylinder is automatically adjusted, for example, when the estimated air/fuel ratio becomes an abnormal value, according to operational condition of the internal combustion engine, and the like, thereby securing the stability in the corrective control and preventing the emission from deteriorating.

Abstract: A feedback control system for a multi-cylinder engine using a combustion condition sensor that senses the condition in only one cylinder. The total air flow to the engine is measured and the amount of fuel supplied to other than the sensed cylinders is varied in response to known variations in air flow for a given engine running conditions. The sense cylinder has direct feedback control with no correction.

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: An air-fuel ratio of respective (individual) cylinders of an engine is changed individually from a stoichiometric air-fuel ratio to a lean air-fuel ratio with the change timing of each of respective cylinders deviated and the intake air flow into an engine 11 is changed gradually by opening an air bypass valve in parallel to the changing of the air-fuel ratio. Concurrent change of ignition timing is also disclosed.

Abstract: A system for estimating air/fuel ratios in the individual cylinders of a multicylinder internal combustion engine from the output of a single air/fuel ratio sensor installed at the exhaust system of the engine. A mathematical model is first designed to describe the behavior of the exhaust system which accepts the output of the air/fuel ratio sensor. An observer is designed to observe the internal state of the mathematical model and calculates the output which estimates the air/fuel ratios in the individual cylinders of the engine. In this configuration, when engine speed becomes high, the observer matrix calculation is discontinued, because it is difficult to ensure a time enough for calculation. Similarly, at a low engine load etc., the calculation is discontinued. Apart from the above, when a desired air/fuel ratio changes frequently such as when air/fuel ratio perturbation control is conducted, the desired air/fuel ratio is input to the observer as a second input.

Abstract: A system for estimating air/fuel ratios in the individual cylinders of a multicylinder internal combustion engine from an output of an air/fuel ratio sensor installed at an exhaust system of the engine. In the system, the exhaust system behavior is derived by a model in which X(k) is observed from a state equation and an output equation in which an input U(k) indicates air/fuel ratios in the individual cylinder and an output Y(k) indicates of the estimated air/fuel ratio asX(k+1)=AX(k)+BU(k)Y(k)=CX(k)+DU(k)where A, B, C and D are coefficients. And an observer is expressed by an equation using the output Y(k) as an input and the air/fuel ratios in the individual cylinders is estimated from the state variable X. In the system, the coefficient C is set to zero for a cylinder other than most recent m (2.ltoreq.m<n) cylinders. Alternatively, a plurality of the observer matrices are prepared in advance and calculated at the same time.

Abstract: A system for controlling an air-fuel ratio of an air-fuel mixture supplied to each cylinder of a multicylinder internal combustion engine. A first feedback loop is provided for converging a first air-fuel ratio at a location at least either at or downstream of a confluence point of an exhaust system to a first desired air-fuel ratio by multiplying a first feedback gain to a first error therebetween. And a second feedback loop is provided in the first loop for converging a second current air-fuel ratio at each cylinder to a second desired air-fuel ratio by multiplying a second feedback gain to a second error. The first feedback loop and said second feedback loop are connected in series such that the second loop located inside the first loop. With the arrangement.

Abstract: An air/fuel ratio estimator for estimating an air/fuel ratio of a mixture supplied to each cylinder of a multicylinder internal combustion engine through an output of an air/fuel ratio sensor installed at a confluence point of an exhaust system of the engine. The estimator includes first device for assuming the output of the air/fuel ratio sensor as an average value made up of a sum of products of past firing histories of each cylinder weighted by a predetermined value, and establishing a model using the air/fuel ratio as a state variable, a second device for obtaining a state equation with respect to the state variable. An observer is provided to estimate the unmeasured state variable indicative of the air/fuel ratio and the air/fuel ratio at each cylinder is estimated from an output of the observer. In the configuration upper and lower limit is established for the state variable such that it is replaced with its initial value if it exceeds either limit.

Abstract: A variable camless engine valve control system and method of control wherein each of the reciprocating intake and/or exhaust valves (10) is hydraulically controlled and includes a piston (26) subjected to fluid pressure acting on surfaces at both ends of the piston (26), is connected to a source of high pressure fluid (40) in one volume (27) while the volume (25) at the other end is connected to a source of high pressure fluid (40) and a source of low pressure fluid (42), and disconnected from each through action of controlling means such as a computer (74) controlling solenoid valves (64, 68). Optimum intake air and residual gas quantities in each engine cylinder having the aforementioned variable valve control system is assured by controlling electric pulses of variable duration and timing.

Abstract: A control apparatus and method for maintaining equal air flow among cylinders and independently controlling the air/fuel ratio of each individual cylinder, in an internal combustion engine having variable valve control. An air fuel controller generates valve control signals for each individual cylinder by sampling the exhaust gas oxygen sensor, and correlating the samples with corresponding combustion events. The valve lift for each variable lift valve is corrected to operate each cylinder at the desired air flow and air/fuel ratio. The variable valve lift can be accomplished in a camshaft type system incorporating a lost motion mechanism or similar device, or a system incorporating direct electrohydraulic or electromechanical valve actuation without a camshaft. The system and method can provide further flexibility in cylinder to cylinder air/fuel ratio control by combining it with a variable pulse width electronic fuel injector capability.

Abstract: The invention relates to a system for controlling an internal combustion engine (100), in particular a self-igniting internal combustion engine. A signal (U) for triggering a performance-determining final controlling element (105) is stored in a characteristics map (110) for each of a corresponding fuel quantity (QK) to be injected into the engine. The signal values stored in the characteristics map (110) are then corrected in dependence upon a predetermined relationship of a signal corresponding to the value for the fuel quantity (QK) to be injected and a signal corresponding to the value for the actually injected fuel quantity (QKI).

Abstract: An air fuel ratio control system for an internal combustion engine, comprising: an internal combustion engine having a plurality of cylinders, and exhaust passages corresponding to the respective cylinders; a plurality of oxygen sensors arranged in the respective exhaust passages to detect the composition of exhaust gas from the respective cylinders; and a control unit for independently controlling an air fuel ratio of the respective cylinders based on outputs from the oxygen sensors.

Abstract: An air-fuel ratio feedback control method for a multi-fuel internal combustion engine using a dual O.sub.2 sensor system is provided, in which the concentration of oxygen in exhaust gas on the upstream side of an exhaust gas purifier is detected, a value corresponding to the detected oxygen concentration is compared with a first target value, and the air-fuel ratio is feedback-controlled in accordance with the result of the comparison. The mixture ratio of at least two fuels is detected, and a second target value is set in accordance with the detected fuel mixture ratio. On the other hand, the concentration of oxygen in the exhaust gas on the downstream side of the exhaust gas purifier is detected, and a value corresponding to the detected downstream-side oxygen concentration is obtained. The first target value is corrected in accordance with the difference between the obtained value and the second target value.

Abstract: The invention is directed to a method and arrangement for controlling a self-igniting internal combustion engine. The arrangement includes at least one measured-value sensor, electronic control unit for forming a quantity signal for metering fuel, and a control unit for driving individual actuators for each cylinder. The actuators determine the quantity of fuel injected by the pump elements into the cylinders. Under specific conditions, a corrective unit is activated which determines corrective values specific to the cylinders for making the cylinders equal. The open-loop control unit applies the metering signal to the actuators in dependence upon the quantity signal and the corrective values.

Abstract: Only an air-fuel ratio of one specific cylinder is forcibly shifted by the correction of the fuel supply quantity, and the fuel supply characteristic error rate of fuel supply means of this one specific cylinder, where the air-fuel ratio is forcibly shifted is detected based on whether or not the influence of this shifting of the air-fuel ratio is manifested on the air-fuel ratio feedback correction value set, based on the average air-fuel ratio in respective cylinders, as expected. Correction values of the fuel supply quantity are set separately for respective cylinders, based on the fuel supply characteristic error rates thus determined separately for respective cylinders.

Abstract: In a fuel supply control system of an internal combustion engine having a function of feedback-controlling the air-fuel ratio, dispersions of the fuel supply characteristics in respective cylinders are corrected by changes of the air-fuel ratio by the correction of the fuel supply quantity. Factors causing the deviations of the air-fuel ratio are independently compensated by learning the correction value for correcting the fuel supply quantity only at a certain ratio and the correction value for correcting the fuel supply quantity only by a certain quantity so that these correction values are commonly fit for at least two different driving conditions.