Abstract: An arrangement for determining the concentration of a component in a gas mixture includes a first volume in which the concentration of the component is maintained constant with respect to the influence of the coupling to the concentration in the gas mixture. The coupling acts via a diffusion resistance. The above-mentioned influence of the coupling is compensated via a controllable flow of ions of the component through a solid electrolyte between the first volume and the gas mixture. The solid electrolyte serves as the pump device. The intensity of the pump current defines a measure for the wanted concentration in the gas mixture. The above-mentioned flow is controlled as a function of the deviation of the output voltage of a Nernst cell from a desired value. The Nernst cell is between a first volume and a reference gas volume.

Abstract: An improved feedback control system and method for internal combustion engines that permits extremely accurate feedback control. This is done by utilizing a sensor device that is interrelated with the combustion chambers of the engine so that it only samples the gases from the engine at a time after the exhaust port has opened and before any fresh air charge enters the combustion chamber. By doing this, it is possible to ensure that only combustion product reach the sensor and the sensor chamber will have a time to purge itself of the combustion products from one cylinder before another sampling takes place. This is described in conjunction with both two and four-cycle engines.

Abstract: A device is provided for detecting a malfunction of an air fuel ratio sensor disposed downstream of a catalytic converter in an exhaust passage of an engine. The device calculates a differential value of a sensor output with respect to time. Then the device compare the differential value of said sensor output with a predetermined value and calculate a frequency of the differential value of the sensor output which exceeds the predetermined value. Then the device compares the frequency with a predetermined value and determine that the sensor is malfunctioning if the frequency does not exceed the predetermined value.

Abstract: A method and system of combustion control for an internal combustion engine (313) proximate an extinction limit includes measurement of acceleration behavior of the internal combustion engine and providing a measure of combustion variability dependent thereon. Preferably, the combustion variability measure is derived by one or more stochastically based methods (607). Operation of the internal combustion engine (313) is controlled dependent on the combustion variability measurement. Fuel, ignition, and exhaust gas recirculation may all be controlled by the derived combustion variability measurement to significantly reduce hydrocarbon (HC) and NO.sub.x emissions.

Abstract: An air-fuel ratio sensor comprises a platelike oxygen sensing section made of a solid electrolyte and a heater sheet heating the oxygen sensing section. The oxygen sensing section and the heater sheet are stacked via spacers to constitute a multilayer construction. The heater sheet comprises a first platelike insulating sheet chiefly containing at least one component selected from the group consisting of .alpha.-alumina, steatite and mullite, a filmy resistance element disposed on the first insulating sheet and having a resistance-temperature coefficient within a range of 0.5.times.10.sup.3 to 2.0.times.10.sup.3 ppm/.degree.C., and a second platelike insulating sheet covering the resistance element and chiefly containing at least one component selected from the group consisting of .alpha.-alumina, steatite and mullite.

Abstract: A system for improving efficiency and reducing harmful emissions in an innal combustion engine and for allowing the engine to run in oxygen poor and oxygen depleted environments. An oxidant, such as hydrogen peroxide, is emulsified with engine fuel. The emulsion is injected into the combustion chamber of the engine. A controller senses the temperature and oxygen level in the exhaust stream of the engine as well as the oxygen level in the ambient fluid. The controller operates a valve to vary the amount of oxidant added to the fuel as well as controlling the amount of ambient air introduced into the chamber and the injection of the fuel oxidant emulsion into the chamber. The controller parameters are set to maintain maximum efficiency and minimum emissions. The oxidant in the emulsion provides for near stoichiometric combustion to reduce combustion products and reduce the engine's air requirements.

Abstract: A method for controlling a piston-type internal combustion engine including dosing a fuel amount conditional upon a desired engine output and dosing a required air amount by controlling opening times of at least the gas intake valves.

Abstract: A method is provided for determining valve control times for a maximum charge for cylinders in a piston-type internal combustion engine provided with fuel injection, lambda sensor control and electromagnetically actuatable cylinder valves. The method includes setting the "intake closes" control moment to a preliminary value on all gas intake valves of the engine; changing continuously the "intake closes" control moment on the gas intake valves at least one cylinder while maintaining a constant engine rpm and determining, with the lambda sensor control at .lambda.=1, one of (1) a longest fuel injection duration and (2) a leanest operation at a constant injection duration; and storing the determined "intake closes" control moments at respective rpm's in a performance characteristic of an engine control for achieving a maximum charge in the cylinders at the respective rpm's.

Abstract: A method and system for the control of the fuel injection timing in an internal combustion engine using a low cetane quality fuel such as an aqueous fuel emulsion is provided. The disclosed system includes a compression ignition engine adapted to receive a prescribed supply of an aqueous fuel emulsion. The prescribed supply of fuel is preferably determined by an fuel system control unit as a function of one or more engine operating parameters. The disclosed system also includes an exhaust sensor located proximate the engine exhaust so as to detect the presence and level of selected exhaust products, such as carbon monoxide, in the engine exhaust. The level of carbon monoxide or other such exhaust product, as measured by the sensor, is input to the engine control unit where it is processed together with various other engine operating parameters to produce a prescribed fuel injection timing signal which operatively controls the fuel injection timing.

Abstract: A combustion control system and method for operating an internal combustion engine to provide the desired air/fuel ratio under all running conditions. The system includes a feedback control which received output from an oxygen sensor coupled to one of the combustion chambers of the engine, the feedback control operating 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 system also includes a mechanism for controlling backfire during operation of the feedback control. Backfire corresponding to the cylinder including the sensor is controlled by the system in a manner independent of the feedback control. Backfire corresponding to all other cylinders may be controlled independently of the feedback control or by changing overall feedback control parameters.

Abstract: A method is provided for automatic calibration of an angle mark transmitter at the crankshaft of an internal combustion engine having fuel injection, Lambda sensor control and electromagnetically actuated gas cylinder valves. The control time "intake closes" is initially adjusted for all gas cylinder valves to a preliminary value. For defined marginal operating conditions, in particular speed and temperature, the control time "intake closes" for at least one gas cylinder valve is changed to determine, via the Lambda sensor control at Lambda=1, a value at which the longest fuel injection time is detected or, for a constant injection time, the leanest operation is detected. The determined control time is compared to the desired control time for an exactly adjusted angle mark transmitter on the internal combustion engine and in case of deviation is compensated for in the control for the internal combustion engine.

Abstract: An internal combustion engine (360) is provided with a plurality of sensors to monitor the operation thereof with respect to various temperature measurements, pressure measurements, etc. A predictive model processor (322) is provided that utilizes model parameters stored in the memory (324) to predict from the sensor inputs a predicted emissions output. The model is trained with inputs provided by the sensor and an actual emissions sensor output. During operation, this predicted output on line (326) can be utilized to provide an alarm or to be stored in a history database in a memory (328). Additionally, the internal combustion engine (260) can have the predicted emissions output thereof periodically checked to determine the accuracy of the model. This is effected by connecting the output of the engine to an external emissions sensor (310) and taking the difference between the actual output and the predicted output to provide an error.

Abstract: The invention is directed to a circuit for processing a signal (UL) of a lambda probe having a probe signal terminal on which the signal (UL) is outputted and a probe ground terminal. The circuit includes a voltage source having a plus pole and having a minus pole connected to the probe ground terminal. A first network of passive components is connected between the plus pole and the probe signal terminal for dividing the voltage between the plus pole and the probe signal terminal in a pregiven ratio thereby providing a divided potential as a first analog signal. An analog-to-digital converter has an input and is connected to a chassis ground at a ground potential different than the ground potential at the probe ground terminal. A second network of passive components is connected to the plus pole for supplying a potential proportional to the potential on the plus pole as a second analog signal.

Abstract: A self-diagnostic apparatus of an air-fuel ratio control system of an internal combustion engine performs processes of starting the diagnostic process as the fuel-cut is started, reading and storing a sensor output at the start of the fuel-cut and counting an elapsed time after the start of the fuel-cut by actuating a timer, reading a time until when the sensor output rises from the start of the fuel-cut from the count value of the timer, calculating a rate of change of the sensor output and comparing the calculated rate of change with an abnormality determining value. When the rate of change is large, the response characteristic of the sensor is normal. When it is small, the response characteristic of the sensor is abnormal (degraded), so that the abnormality of the sensor is stored in a memory and an alarm lamp is lighted to inform a driver of the abnormality of the sensor.

Abstract: The invention relates to a combination of a heated lambda sensor with a stepped or binary sensor characteristic and another heated lambda sensor to determine the lambda value in a gas mixture, e.g. in the exhaust gas preferably of internal combustion engines, the output signal from one lambda sensor being used to calibrate the other one, and the two lambda sensors are arranged closely beside each other, the other lambda sensor having a wide-baud sensor characteristic.

Abstract: An air/fuel control method for an internal combustion engine. A portion of fuel delivered to the engine which is lost between the piston and engine cylinder walls during predetermined engine operating conditions is calculated. Fuel delivered to the engine is then adjusted for the calculated lost fuel quantity to achieve a desired engine air/fuel ratio.

Abstract: A process and apparatus for monitoring catalyst conversion activity includes a predictor of feedgas emissions and a predictor of tailpipe emissions, each predictor providing an output for generating a ratio of conversion activity. Each predictor comprises a trained neural network receiving at least one of, and preferably a plurality of, the engine operating condition signals available from an electronic engine control. Preferably, each neural network is trained by inputting accumulated data acquired from performance evaluation of a plurality of vehicles having consistent powertrains but with different degrees of deterioration.

Abstract: A two-cycle internal combustion engine configuration and control strategy in which the unburned hydrocarbon emissions are measured in the exhaust manifold during the scavenging process using a fast response air fuel sensor. The signal from the sensor is used to control the operation of a low pressure ratio blower and the inlet fuel and oil flow. In this way the inlet flow of fuel and air may be reduced which controls the short circuiting loss of fuel during the scavenging process and reduces unburned hydrocarbons in the exhaust gas.

Abstract: A method and apparatus are disclosed for measuring atmospheric pressure in conjunction with an air-fuel ratio sensor of the type comprising a concentration cell with atmospheric air and exhaust electrodes on opposite sides of a solid-state electrolyte having oxygen ion conductivity. During an atmospheric pressure measuring cycle, oxygen ions are pumped from the atmospheric air electrode to the exhaust electrode, in a quantity which is either predetermined at a fixed value, or is sufficient to bring the cell to an equilibrium state. Atmospheric pressure is then calculated from measured emf of the cell, using an experimentally derived functional relationship. In a second embodiment, ions are pumped until a predetermined change of the concentration cell emf is achieved, and atmospheric pressure is determined based on the amount of time required to achieve such change. The atmospheric pressure measuring mode is operated on a time shared basis with the air-fuel ration detection mode.

Abstract: A boron nitride ceramic is used as a high temperature gasket material to prevent gas leakage between an exhaust gas oxygen sensor and the exhaust system of an internal combustion engine.

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 diagnostic apparatus applied to internal combustion engine exhaust gas sensors employing electrochemical polarographic principles indicates sensor operation relative to a current limiting operating region in which a sensor output signal indicates oxygen concentration in the exhaust gas. A sensor drive signal is controllably perturbed and sensor sensitivity monitored by monitoring the sensor response to the perturbation. Current limiting operation may be diagnosed and indicated when the sensor response indicates an insensitivity to the perturbation.

Abstract: An internal combustion engine [(360)] is provided with a plurality of sensors to monitor the operation thereof with respect to various temperature measurements, pressure measurements, etc. A predictive model processor [(322)] is provided that utilizes model parameters stored in the memory [(324)] to predict from the sensor inputs a predicted emissions output. The model is trained with inputs provided by the sensor and an actual emissions sensor output. During operation, this predicted output on line [(326)] can be utilized to provide an alarm or to be stored in a history database in a memory [(328)]. Additionally, the internal combustion engine [(260)] can have the predicted emissions output thereof periodically checked to determine the accuracy of the model. This is effected by connecting the output of the engine to an external emissions sensor [(310)] and taking the difference between the actual output and the predicted output to provide an error.

Abstract: A system, and a corresponding method, for measuring a chemical concentration of a gas exhausted from exhaust ports (409, 413) of a multi-cylinder internal combustion engine (401) includes a gas sensing device. This device (419) is preferably a UEGO (Universal Exhaust Gas Oxygen) sensor. The gas exhausted is present in a substantially stable chemical concentration (706, 718) at a collection point (420) during intervals (738, 742) of engine angular rotation corresponding to the exhaust cycles. The UEGO sensor (419) measures the gas exhausted from the exhaust ports (409, 413) and provides a sensory output signal (743) that, during the intervals (738, 742) of engine angular rotation corresponding to each of the exhaust cycles, approaches (737, 741) a substantially stable value representative of the chemical concentration of the gas (706, 718) exhausted during the associated exhaust cycle.

Abstract: A method for detecting and controlling the air-fuel ratio of a multicylinder internal combustion engine through an output of a single air-fuel ratio sensor installed at a confluence point of the exhaust system of the engine. The detection response delay is assumed to be a first-order lag and a state variable model is established. Further, the air-fuel ratio at the confluence point is assumed to be a sum of the products of the past firing histories of the each cylinder of the engine and a second state variable model is established. An observer is then designed to observe the internal state of the second model and the air-fuel ratio at the individual cylinders are estimated from the output of the observer. The deadbeat control is carried out by calculating a ratio between the estimated air-fuel ratio and a target air-fuel ratio. The calculated ratio is multiplied to a correction value at a preceding control cycle earlier by a number corresponding to the number of the engine cylinders.

Abstract: An engine air/fuel control system modulates the flow of fuel delivered to the engine with a modulation signal (100, 144) The feedback variable generated (210-228) from a two-state exhaust gas oxygen sensor (16) corrects the fuel flow (156). During each of a plurality of pre-determined intervals, the fuel flow is biased with a rich offset (342). Amplitude of the modulation signal is corrected by a difference between the feedback variable generated during two successive occurrences of the predetermined interval (346-378).

Abstract: The invention includes a flat plate exhaust sensor including a flat plate sensing element which is carried by a first ceramic insulator having at its upper end an upwardly extending annular ring. The annular ring defines a disc-shaped recess which is filled with a glass seal. Thus, the glass seal extends from the flat plate sensor to the annular ring of the ceramic insulator. The sensor includes an upper tubular shell which includes at the lower end a leg portion which extends inside an inner wall of a lower tubular shell. The leg portion includes a foot which is bent to match an outwardly extending sloped annular shoulder formed on an upper insulator. The upper insulator is seated on the glass seal. An intermediate gasket is formed by an active metal braze gasket between the foot and the outwardly extending sloped annular shoulder of the upper insulator. An external seal is provided by a braze ring which joins an upper end of the lower tubular shell to the upper tubular shell.

Abstract: An arrangement determines a voltage which indicates the lambda value of an air/fuel mixture supplied to a combustion engine generating exhaust gas during the operation thereof. The arrangement includes a two-cell oxygen probe mounted in the exhaust gas flow of the engine. The two-cell oxygen probe has an exhaust-gas space for the exhaust gas and an ambient-air space for ambient air. The oxygen probe has a pump cell having two electrodes and a sensing cell having two electrodes. A switchover stage outputs a voltage indicating the electric pump current through the pump cell when a control to the lambda value deviating from one is to be made and outputs that Nernst voltage which is taken off between the electrodes of the sensing cell facing into the ambient air and one of the remaining ones of the electrodes when a control to the lambda value one is to be made. For controlling to the lambda value one, the Nernst voltage supplies a significantly more precise signal than the voltage derived from the pump current.

Abstract: A new two-cycle internal combustion engine configuration and control strategy in which the unburned hydrocarbon emissions are measured in the exhaust manifold during the scavenging process using a fast response air fuel sensor. The signal from the sensor is used to control the operation of a low pressure ratio blower and the inlet fuel and oil flow. In this way the inlet flow of fuel and air may be reduced which controls the short circuiting loss of fuel during the scavenging process and reduces unburned hydrocarbons in the exhaust gas.

Abstract: A method of supplying a combustible gas into a combustion chamber of an internal combustion engine of the cylinder type during two phases. The supply of combustible gas is restricted at least towards the end of the first phase and restricting the supply of the combustible gas is terminated at least during the beginning of the second phase which ends when the piston begins to compress a charge in the combustion chamber. In this method the extent of restricting the supply of combustible gas and the times of starting and terminating to restrict the supply of combustible gas and the time of terminating the supply of combustible gas are coordinated such that the resultant piston work corresponds to the work necessary for filling the combustion chamber with a desired amount of combustible gas plus the energy necessary to increase the temperature of the charge for a predetermined amount.

Abstract: The invention is directed to a method of determining the performance loss of a catalyzer by using a deterioration variable indicative of this performance loss. The catalyzer is affected by operating conditions and is mounted in the exhaust gas flow of an internal combustion engine having a lambda controller operated to provide a two-level response. The method includes the steps of: obtaining a measurement signal from a lambda probe mounted forward of the catalyzer and a test signal from a lambda probe mounted rearward of the catalyzer; forming a relationship between the measurement and the test signals; measuring values of operating variables which affect oxygen storage processes in the catalyzer; and, correcting the deterioration variable based on the values of the operating variables thereby reducing the influence of the operating conditions on the deterioration variable.

Abstract: In a method of controlling the fuel-air ratio of an internal combustion engine the combustion chamber and its contents are preheated at times when the engine is started from cold and during other operative conditions of thermal energy deficiency. The engine is operated with a lean fuel-air mixture from the very beginning when the engine is started, and the fuel-air ratio is controlled exclusively by oxygen sensor means in the exhaust gas.

Abstract: A first O.sub.2 sensor is installed upstream, and a second O.sub.2 sensor downstream, of the catalyst converter in the exhaust passage of an engine. It is judged from the output of this first O.sub.2 sensor whether the air-fuel ratio (AFR) has changed beyond the theoretical AFR, and AFR feedback control is performed based on the judgment result. A correction value of an AFR feedback control coefficient is previously stored in each learning area in a memory corresponding to the engine running conditions, and the fuel injection amount supplied by the fuel injector is corrected based on this correction value.The correction value is updated by an updating amount corresponding to the magnitude of the difference between the output of the second O.sub.2 sensor and a value corresponding to the theoretical AFR. Undershoot or overshoot of the AFR is thereby prevented, and the AFR is rapidly brought within a desired range.

Abstract: A flexible fuel vehicle is a vehicle capable of operating on alcohol, gasoline, or any combination of these two fuels. Because of the unique properties of alcohol fuels, modifications to engine operating characteristics are required to compensate for the varying percentage of alcohol in the fuel. A method is provided for determining the percent alcohol content of the fuel in the fuel tank, utilizing the oxygen sensor feedback control loop to sense changes in air/fuel ratio and relay that information to the engine controller so that dependant variables can be adjusted accordingly. The method includes placing the fuel pump in the fuel tank along with a mixed fuel accumulator so that a known and slowly varying percentage of alcohol in the fuel is provided to the engine, especially during open loop operation.

Abstract: An air-fuel ratio control system compares an air-fuel ratio indicated by air-fuel ratio information from an air-fuel ratio sensor and a target air-fuel ratio determined depending on operating conditions of a motor vehicle which incorporates the air-fuel ratio control system, for reliably determining at least a failure of the air-fuel ratio sensor. When a failure of the air-fuel ratio sensor is detected, an air-fuel ratio feedback control process is stopped or the air-fuel ratio sensor is disabled, preventing the air-fuel ratio from being corrected in error based on an output signal from the air-fuel ratio sensor which has failed. Therefore, the air-fuel ratio control system prevents problems such as poor exhaust gas purification, reduced drivability, and unstable engine idling from taking place.

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: A fuel blending ratio detecting method computes a control blending ratio on the basis of blending ratio information generated from a blending ratio sensor or air/fuel ratio information generated from an O.sub.2 sensor, and when the engine is stopped, the control blending ratio detected at that time is stored in a backup memory as a memory blending ratio. At the time of re-starting the engine, the memory blending ratio can be used as the control blending ratio B for a predetermined limited period.

Abstract: An air-fuel ratio control method for an internal combustion engine. The air-fuel ratio of an air-fuel mixture supplied to the engine is feedback-controlled to a predetermined value in response to an output from the exhaust gas ingredient concentration sensor. The temperature of at least one component part of the engine, which should be controlled, is estimated based on the detected temperature of exhaust gases, engine rotational speed, and engine load. The air-fuel ratio of the air-fuel mixture is inhibited from being feedback-controlled but enriched, when the estimated temperature of any one of the at least one component part of the engine is higher than a corresponding predetermined value.

Abstract: An air-fuel ratio control apparatus for an internal combustion engine controls a fuel supplying means by a signal generated from an air-fuel sensor so that the air-fuel ratio of a gas mixture to be sucked into the internal combustion engine becoms a target air-fuel ratio. The air-fuel ratio control apparatus corrects the target air-fuel ratio by a parameter on the condition of the engine detected by the detecting means so that a fuel supplying device is controlled to obtain a corrected target air-fuel ratio.

Abstract: A petrol injection system for an internal combustion engine, the system being adapted to provide additional petrol into the inlet manifold of the engine during acceleration conditions in order to compensate for the less efficient transference of vaporized fuel to the engine cylinders during acceleration conditions, the quantity of additional fuel (BA) being determined in accordance with a stored enrichment value (FBAAM) which is adjusted regularly to take into account changing engine conditions. During the warming-up phase of the engine when the normal lambda regulation is inactive, the magnitude and direction of adjustment of the acceleration enrichment value (FBAAM) is derived from the behavior of the rotational speed (n) of the engine and the .lambda. probe signal (.lambda.>1 or .lambda.<1) during an acceleration enrichment operation in that if, during an acceleration enrichment operation in the warming-up phase of the engine, it is detected that the .lambda.

Abstract: In methods for adaptively adjusting a fuel/air mixture, the adaptation factor is rapidly adjusted to take fuel characteristics into account when it develops that after tanking, poor control results are obtained with the adaptation factor previously applicable. As soon as there is an adjustment again to good control results, the conventional relatively slow adaptation is carried out. These methods afford the advantage that they can be carried out without special expensive mixture sensors.