Abstract: The present disclosure shows a system for checking a correct mounting of a plurality of sensors, in particular of sensors mounted in an engine system, comprising a controller configured for receiving signals from the plurality of sensors. The controller is configured to monitor a sequence and/or timing of the signals received from the sensors and to evaluate it with respect to a sequence and/or timing of a switching of a power supply to the sensors for checking the correct mounting of the sensors.

Abstract: When a request for temperature increase of a three-way catalyst is made, a CPU executes dither control in which one of a plurality of cylinders is set as a rich combustion cylinder with a richer air-fuel ratio than a stoichiometric air-fuel ratio and the remaining cylinders are set as lean combustion cylinders with a leaner air-fuel ratio than the stoichiometric air-fuel ratio. When not executing the dither control, the CPU learns a rich learning value that is a learning value of a degree of a rich imbalance based on an upstream-side air-fuel ratio. When the rich learning value is greater than or equal to a predetermined value, the CPU prohibits the dither control.

Abstract: A controller for an internal combustion engine may comprise a first assignment unit, an observer, a calibration unit, and a second assignment unit. The first assignment unit may determine cylinder-specific measurement signals as a function of the measurement signal from a lambda probe. The observer may include a sensor model of the lambda probe arranged in a feedback branch of the observer. The calibration unit may impress a predefined interference pattern made of cylinder-specific mixture differences and adapt, in reaction to the respectively predefined interference pattern as a function of the observer output variables related to the respective cylinders, an assignment rule between the measurement signal of the lambda probe and a lambda signal. The second assignment unit may carry out, by means of the assignment rule, an assignment between the measurement signal and the lambda signal.

Abstract: A method for operating an internal combustion engine is described in which a combustion air ratio (?) is determined and used to determine a deviation of this combustion air ratio from an in particular default or determined set point combustion air ratio. Spontaneous ignition of the internal combustion engine are detected based on the determined deviation (??) and used to control the operation of the engine.

Abstract: An air-fuel ratio region detection unit, including a first determination voltage higher than a target voltage value indicating the stoichiometric air-fuel ratio, and a second determination voltage lower than the target voltage value, determines that an air-fuel ratio of an engine is within a first rich region when an oxygen sensor output equals or exceeds the first determination voltage, determines that the air-fuel ratio is within a second rich region when the oxygen sensor output equals or exceeds the target voltage value but is lower than the first determination voltage, determines that the air-fuel ratio is within a second lean region when the oxygen sensor output equals or exceeds the second determination voltage but is lower than the target voltage value, and determines that the air-fuel ratio is within a first lean region when the oxygen sensor output is lower than the second determination voltage.

Abstract: An internal combustion engine control apparatus includes a first period in which the target heater applied effective voltage is set to a first target voltage with which the temperature of an exhaust gas sensor becomes a target temperature at a time when the internal combustion engine is being operated; a second control period in which after the automatic stop mode of the engine has started, the target heater applied effective voltage is set to a second target voltage lower than the first target voltage; and a third period in which after the second period, the target heater applied effective voltage is controlled to a third target voltage higher than the second target voltage and with which the temperature of an exhaust gas sensor becomes a target temperature at a time when the engine is in the automatic stop mode.

Abstract: A method of determining an air-fuel ratio of an internal combustion engine in real-time includes: calibrating sensitivity of a universal exhaust gas oxygen sensor to a plurality of gases; inputting to a universal exhaust gas oxygen sensor controller a molecular composition of Hydrogen, Carbon, Oxygen, and Nitrogen which comprise a combustion fuel in use in the internal combustion engine; calculating with the universal exhaust gas oxygen sensor controller an air-to-fuel ratio by performing a chemical balance equation calculation based on the universal exhaust gas oxygen sensor sensitivity calibration and the input combustion fuel molecular composition; and transmitting the calculated air-to-fuel ratio to an engine control unit in real-time.

Abstract: A computer-implemented method is used to correct deviations between a predicted gas excess air ratio and a calculated excess air ratio in a dual fuel engine or other gas fueled compression ignition engine. The method includes determining gas excess air ratio for the engine based at least in part on at least one detected current operating parameter and calculating a predicted exhaust gas oxygen concentration engine based on the predicted gas excess air ratio. A time based filtered predicted exhaust gas oxygen concentration value may then be calculated and compared to a time-based filtered measured exhaust gas oxygen concentration value. The resultant oxygen concentration deviation value may be used to generate a corrected predicted gas excess air ratio.

Abstract: An air-fuel ratio diagnostic device for an internal combustion engine. The device includes an air-fuel ratio that detects oxygen concentration in the exhaust. A determination unit determines a variation in air-fuel ratio between engine cylinders based on a detection value of the air-fuel ratio sensor. A change amount in the detection value for a certain time when the detection value is changing from a lean side peak value toward a rich side peak value is defined as a rich change rate. A change amount in the detection for a certain time when the detection value is changing from a rich side peak value toward a lean side peak value is defined as a lean change rate. The determination unit determines a degree of variation between the cylinders based on the rich and lean change rates.

Abstract: An engine control system includes a proportional correction module and a variable proportional gain determination module. The proportional correction module generates a proportional correction for a fuel command to an engine based on a variable proportional gain and a difference between expected and measured amounts of oxygen in exhaust gas produced by the engine. The variable proportional gain determination module determines the variable proportional gain based on a nominal gain and an amount of time since a polarity of the difference has changed, wherein the nominal gain is based on engine operating parameters.

Abstract: A passive control device is interposable between an oxygen sensor and an electric control unit of a motor vehicle to modify a reference voltage used by the electric control unit so that a richer fuel mixture is provided to an internal combustion engine of the motor vehicle than would otherwise be provided in absence of the passive control device. The passive control device directly passes the voltage signal from the oxygen sensor to the electronic control unit without modification. The passive control device works with the electronic control unit to provide a richer fuel mixture without reprogramming the electronic control unit.

Abstract: An interface device for a gas sensor includes a detection resistor having first and second ends to generate voltages by a current output of the gas sensor, a differential amplifier having first and second input terminals to receive the voltages of the first and second resistor ends and an output terminal to output a voltage according to a difference between the voltages of the first and second resistor ends, a first switching element to transmit the voltage of the first resistor end to the first input terminal of the differential amplifier in a transmission state and interrupt transmission of the voltage of the first resistor end to the first input terminal of the differential amplifier in an interruption state and a second switching element turned on to establish continuity between the first and second input terminals of the differential amplifier when the first switching element is in the interruption state.

Abstract: A correction apparatus for correcting an output of an oxygen sensor installed in an exhaust pipe of an internal combustion engine to measure the concentration of oxygen contained in exhaust gas. The apparatus works to execute a fuel cut operation to bring the pressure in the exhaust pipe to the atmospheric pressure and enters an under-atmosphere correction mode to sample an output of the oxygen sensor and determine a correction factor compensating for a deviation of the sampled output from a reference value representing an actual concentration of oxygen. The apparatus also works to calculate the pressure in the exhaust pipe after start of the fuel cut and determine whether the under-atmosphere correction mode is to be entered or not based on the pressure of exhaust gas, thereby ensuring the accuracy in correcting the output of the oxygen sensor regardless of a variation in the pressure of exhaust gas.

Abstract: A control apparatus and method, and an engine control unit for an internal combustion engine are provided for restraining a torque step and sudden fluctuations in rotation when an air/fuel mixture combustion mode is switched among a plurality of combustion modes, and for improving the fuel economy. A control apparatus of an internal combustion engine operated with a combustion mode switched between a stratified combustion mode and a uniform combustion mode comprises an ECU. The ECU calculates an ignition manipulated variable to cancel out a change in the engine rotational speed associated with the switching of the combustion mode when a first-time injection ratio changes during idle rotational speed control, and calculates an intake manipulated variable to cancel a change in the engine rotational speed caused by the ignition manipulated variable when the first-time injection ratio changes.

Abstract: An engine control strategy that ensures that NOx emissions from the engine will be maintained at an acceptable level. The control strategy is based on a two-dimensional fuel-air curve, in which air manifold pressure (AMP) is a function of fuel header pressure and engine speed. The control strategy provides for closed loop NOx adjustment to a base AMP value derived from the fuel-air curve.

Abstract: A neural network controller in parallel with a proportional-plus-integral (PI) feedback controller in a control system. At least one input port of the neural network for receiving an input signal representing a condition of a process is included. A first set of data is obtained that includes a plurality of output values of the neural network obtained during a training period thereof using a plurality of first inputs representing a plurality of conditions of the process. The process/plant condition signals generally define the process/plant, and may include one set-point as well as signals generated using measured systems variables/parameters. In operation, the neural network contributes to an output of the PI controller only upon detection of at least one triggering event, at which time a value of the first set of data corresponding with the condition deviation is added-in thus, contributing to the proportional-plus-integral feedback controller.

Abstract: A method for operating an internal combustion engine, permitting a differentiation between an air error and a fuel error as part of mixture adaptation. In at least one operating state of the internal combustion engine a deviation in an air-fuel mixture ratio from a setpoint value is corrected. For this correction in the at least one operating state the particular deviation in the air-fuel mixture ratio is determined for at least two setpoint values. From these deviations an air error and/or a fuel error is determined.

Abstract: A control valve module for gaseous fuels on spark ignited reciprocating engines is presented. The control valve module has a valve that controls gaseous fuel flow to a mixer or other device for air/fuel ratio control, an actuator for moving the valve position, and a controller. The controller receives a signal from a heated exhaust gas oxygen (HEGO) sensor that is an indication of the fuel/air ratio and actuates the valve to control the combustion mixture to a precise stoichiometric ratio.

Abstract: A control valve module for gaseous fuels on spark ignited reciprocating engines is presented. The control valve module has a valve that controls gaseous fuel flow to a mixer or other device for air/fuel ratio control, an actuator for moving the valve position, and a controller. The controller receives a signal from a heated exhaust gas oxygen (HEGO) sensor that is an indication of the fuel/air ratio and actuates the valve to control the combustion mixture to a precise stoichiometric ratio.

Abstract: An air-fuel ratio correction coefficient calculating component is provided to an air-fuel ratio controller for an engine having the wide range air-fuel ratio sensor. In order to compensate for a time lag in detection of an air-fuel ratio detected by the wide range air-fuel ratio sensor from the time when a mixed gas of the air-fuel ratio is supplied to the engine, the air-fuel ratio controller includes a component for calculating an air-fuel ratio correction coefficient to control an amount of fuel supplied to the engine based on an output signal of the air-fuel ratio sensor. The air-fuel ratio correction coefficient calculating component calculates the air-fuel ratio correction coefficient based on a nonlinear calculation element. The non-linear calculation element has an ON-OFF characteristic, a neutral zone characteristic, a saturation characteristic or a characteristic combining a plurality of characteristics selected from the above-mentioned characteristics.

Abstract: A circuit for improving the resolution of an oxygen sensor in a vehicle exhaust system. The circuit expands a limited output voltage range of an oxygen sensor to full voltage range of an analog-to-digital (A/D) converter, prior to input of the expanded signal into the A/D converter. Utilization of the full range of converter provides improved resolution for analyzing the analog signal.

Abstract: An air-fuel ratio correction coefficient calculating component is provided to an air-fuel ratio controller for an engine having the wide range air-fuel ratio sensor. The air-fuel ratio correction coefficient calculating component can cope with a time lag in detection of an air-fuel ratio detected by the wide range air-fuel ratio sensor from the time when a mixed gas of the air-fuel ratio is supplied to the engine.

Abstract: Control device in which a linear oxygen sensor arranged on a gas exhaust pipe of an internal-combustion engine upstream of a catalytic converter generates a signal supplied to a conversion circuit generating at its output a measured parameter representing the air/fuel ratio of the mixture supplied to the engine. The measured parameter is compared with a target parameter so as to calculate an error parameter which is used, according to an operating method, to generate, where necessary, a bistable dummy signal variable between a positive saturation value and a negative saturation value so as to model the output of an oxygen sensor of the ON/OFF type. The dummy signal is also processed so as to calculate a correction parameter designed to be used for correction of a theoretical value of a calculated quantity of fuel, obtaining a corrected quantity of fuel for an injection system of the engine.

Abstract: A fuel blending ratio inferring method responsive to an air/fuel feedback control system for an internal combustion engine is disclosed having a feedback correction loop generating a feedback variable derived from an output of an exhaust gas sensor. A fuel blending ratio is inferred in response to a refueling indication by observing the size and magnitude of the feedback variable. Thus, the effect of the fuel blend can be isolated from other errors in the feedback control system.

Abstract: A method for utilizing a wide range oxygen sensor voltage output that is proportional to exhaust gas fuel air mixture to correct for variations in a flexible fueled vehicle's fuel alcohol content is provided for a vehicle not equipped with an alcohol sensor.

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: An air/fuel control system for an engine (28) provides an air/fuel indicating signal linearly related to average engine air/fuel operation from a two-state exhaust gas oxygen sensor (44). Fuel delivered to the engine is modulated with a periodic signal (144). A reference value corresponding to a desired air/fuel ratio is subtracted from a rolling average of the exhaust gas oxygen sensor output to provide an error signal (148-152). A feedback variable (FV) for adjusting the engine air/fuel ratio is generated from a proportional plus integral controller having the error signal as its input (156). In this manner, average engine air/fuel ratio is maintained at the desired air/fuel ratio and the rolling average of the exhaust gas oxygen sensor output provides an air/fuel indicating signal.

Abstract: An air/fuel control system for an engine (28) provides an air/fuel indicating signal linearly related to average engine air/fuel operation from a two-state exhaust gas oxygen sensor (44). Fuel delivered to the engine is modulated with a periodic signal (144). Adaptive feedback control (steps 200-280) adaptively learns a desired amplitude for the periodic signal to generate the air/fuel indicating signal with desired sensitivity and operating range.

Abstract: An alr-fuel ratio controller for-an internal-combustion engine is provided with front and rear O.sub.2 sensors respectively installed in the exhaust system on the upstream and downstream sides of an exhaust gas purifier. The controller corrects the air-fuel ratio in accordance with the result of the comparison between a detected value of the front O.sub.2 sensor and a first reference value, to thereby control the alr-fuel ratio to a desired value, and also corrects a value of a parameter related preferably to at least one of a correction amount or a correcting timing for the air-fuel ratio correction, e.g., the first reference value, in accordance with the deviation between a detected value of the rear O.sub.2 sensor and a second reference value.

Abstract: An engine air/fuel control system includes an apparatus and method for adaptively learning a reference voltage. Fuel delivered to the engine is trimmed by a feedback variable provided by integrating a two-state signal resulting from a comparison between the reference voltage and the exhaust gas oxygen sensor output. Each sample period of a microprocessor, a high voltage signal and low voltage signal are generated which track the outer envelope of the sensor signal. Calculation of a midpoint between high and low voltage signals provides the reference which instantaneously tracks the midpoint of the sensor signal.

Abstract: An air-fuel ratio feedback correction value is used to correct the quantity of fuel supplied to an engine. The correction value is subjected to proportional-integral control to be carried out according to an air-fuel ratio detected by an oxygen sensor according to the oxygen concentration in exhaust. A response delay time occurring in the air-fuel ratio feedback control system is calculated, and according to the response delay time, the air-fuel ratio feedback correction value is adjusted. Even with the response delay time in the feedback control system, an actual air-fuel ratio is substantially converged to a target air-fuel ratio.

Abstract: In a lean burn control system for an internal combustion engine, when surging in the engine is caused due to lowering of an engine lean limit, a first correction circuit decreases a target air-fuel ratio irrespective of whether the system is operated under an open loop control or a feedback control. On the other hand, when the surging is caused due to variation in output characteristic of an air-fuel ratio monitoring sensor, a second correction circuit decreases the target air-fuel ratio only when the system is operated under the feedback control. Accordingly, the target air-fuel ratio as corrected by the first correction circuit is used in the open loop control, while the target air-fuel ratio as corrected by the first and second correction circuits is used in the feedback control.

Abstract: An exhaust gas cleaning device for controlling the air-to-fuel ratio of the air-fuel mixture supplied to an internal combustion engine (1) provided with a catalytic converter (14) disposed in the exhaust pipe (13). The air-to-fuel ratio is oscillated around the central level of the integral control or proportional plus integral feedback control signal based on the output of an air-to-fuel ratio sensor (12); the amplitude of oscillation and the proportional control amount are, or alternatively, the frequency of the oscillation is, varied in accordance with the operating condition of the engine.

Abstract: A feedback type air-fuel ratio control system controls the air-fuel ratio of air-fuel mixture fed to an internal combustion engine in accordance with an information signal issued from a first oxygen sensor installed in an exhaust line of the engine. The exhaust line has a catalytic converter at a position downstream of the first oxygen sensor. There is further provided a system in the control system, which detects deterioration of the first oxygen sensor. The system comprises a computer and a second oxygen sensor of delayed response type installed in the exhaust line at a position upstream of the converter. The computer defines higher and lower slice levels with respect to the output of the second oxygen sensor and compares the output of the second oxygen sensor with the higher and lower slice levels.

Abstract: An air-fuel control that has two stages of operation. The control includes an EGO sensor interconnected to the exhaust system of an engine and a control assembly. In a first stage of operation, the engine is allowed to operate in an open loop condition. Periodically, however, the control momentarily moves to a second stage of operation. When in the second state, the control assembly ramps up the air-fuel ratio of the air-fuel mixture supplied to the engine until the EGO sensor changes state. The amount that the air-fuel ratio changed during this process is then compared with a nominal value to compute a correction factor. The correction factor is then used during the next open loop interval to increase or decrease the signal applied to the air-fuel distribution control and achieve a more optimum air-fuel mixture.

Abstract: A control unit for controlling an injection amount of a fuel injection valve and performing an air-fuel ratio control of an engine has an oxygen sensor for detecting an air-fuel ratio in an exhaust outlet and an electrode plug for measuring a flame resistance value in a combustion chamber. The control unit calculates a reference air-fuel ratio from an average value of the minimum values of the flame resistance measured by the electrode plug, obtains a correction coefficient from the air-fuel ratio detected by the oxygen sensor and the reference air-fuel ratio, and then corrects the air-fuel ratio detected by the oxygen sensor. The control unit performs the air-fuel ratio control of the engine based on the corrected air-fuel ratio.

Abstract: An air-fuel ratio control apparatus for an internal combustion engine which is equipped with an air-fuel ratio sensor for sensing an actual air-fuel ratio of a mixture to be introduced into the engine and a target air-fuel ratio setting section for setting a target air-fuel ratio of the engine. Also included is a controlled-amount calculating section for setting an optimal feedback gain on the basis of a predetermined dynamic model of the engine to calculate a controlled amount in accordance with the predetermined optimal feedback gain so that the actual air-fuel ratio becomes equal to the target air-fuel ratio. A fuel supply amount to the engine is determined on the basis of the calculated controlled amount, and the control responsiveness of the controlled-amount calculating section is suppressed when the engine is in a speed-decreasing state. This arrangement can adequately control the air-fuel ratio of the engine irrespective of the engine speed-decreasing state.

Abstract: A system for controlling the air/fuel ratio input to a small engine measures the oxygen level in the engine's exhaust and compares it with a reference level. A stepper motor controls the air/fuel ratio and it is advanced one step each time a clock pulse is produced in a direction determined by the level of exhaust oxygen. A fault detector circuit stops the engine if the sensed oxygen level is outside a preset range for more than a preset time interval.

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 desired air-fuel ratio in response to output from an exhaust gas ingredient concentration sensor. When the desired air-fuel ratio is to be changed in a leaning direction from a value equal to or leaner than a stoichiometric air-fuel ratio, it is changed at a larger rate until it reaches a predetermined value than after it has reached the predetermined value. The predetermined value is set to a value slightly leaner than an air-fuel ratio at which the amount of emission of NO.sub.X increases.