Abstract: A power system for a work vehicle, includes an intake arrangement configured to intake charge air; a fuel arrangement configured to provide at least one fuel; a compression ignition engine including a plurality of piston-cylinder sets configured to receive, ignite, and combust the at least one fuel from the fuel arrangement and intake gas that includes the charge air from the intake arrangement to generate mechanical power and exhaust gas; at least one compression ignition assistance apparatus associated with at least one of the intake arrangement and the fuel arrangement; and a controller coupled to command the compression ignition assistance apparatus, the intake arrangement, and the fuel arrangement such that, in an enhancement mode, the controller commands activation of the compression ignition assistance apparatus; and in a nominal mode, the controller commands or maintains deactivation of the compression ignition assistance apparatus.

Abstract: A method for controlling a filling of an exhaust-gas component storage-device of a catalytic-converter in the exhaust-gas of an internal-combustion-engine, in which an actual fill level (?mod) of the exhaust-gas component storage-device is ascertained using a first-system model to which signals (?in,meas) of a first-exhaust-gas probe that extends into the exhaust-gas flow upstream from the catalytic-converter and that acquires a concentration of the exhaust-gas component are supplied, if this first exhaust-gas probe is ready for operation. A lambda-target-value (?in,set) for a first control-loop is specified by a lambda-target-value pilot control, and that, if the first exhaust-gas probe is not ready for operation, a replacement signal for the signal of the first exhaust-gas probe is supplied to the system-model, and the replacement signal is used in the lambda-target-value pilot control as an initial-value for the lambda-target-value. Also described is a control device for the method.

Abstract: An air-fuel ratio detection device 1, 1? comprises: a sensor element 2, 2? including a sensor cell 10; a voltage application circuit 40, 40? applying voltage to the sensor cell; a current detector 42, 42? detecting an output current of the sensor cell; an air-fuel ratio calculating part 61 configured to calculate an air-fuel ratio of an exhaust gas; and a parameter detecting part 62 configured to detect or calculate a temperature correlation parameter correlated with a temperature of the sensor element. The air-fuel ratio calculating part is configured to calculate the air-fuel ratio of the exhaust gas based on the temperature correlation parameter and the output current detected when a predetermined voltage is applied to the sensor cell.

Abstract: A method for operating an internal combustion engine, having of the following steps: operating the internal combustion engine with a gas fuel; detecting a lambda value in the exhaust gas of the internal combustion engine; determining at least one variable from the detected lambda value, characterizing the quality of the gaseous fuel; and controlling the internal combustion engine based on the at least one variable.

Abstract: A system includes an impedance gas sensor configured to be in contact with one or more hydrocarbons. The impedance sensor includes electrodes and a sensing region circuit that is configured to have a sensing material and to generate electrical stimuli to the sensing material upon exposure to one or more hydrocarbons at one or more of a reduced heater voltage or a reduced sensing region temperature as compared to a prescribed heater voltage or a prescribed sensing region temperature. The system also includes one or more processors configured to receive electrical signals from the sensor, where the electrical signals are representative of impedance responses of the sensing material to one or more hydrocarbons. The one or more processors also are configured to analyze the impedance responses and determine an amount of at least one hydrocarbon of interest in the one or more hydrocarbons.

Abstract: A method for controlling variable oil pressure to a piston squirter based on piston temperature according to an exemplary embodiment includes a temperature estimation module and an oil pump pressure control module. The temperature estimation module estimates a piston temperature associated with a cylinder based on engine operating conditions. The oil pump pressure control module controls the oil pressure level delivered to at least one of piston squirter associated with the cylinder to selectively spray oil on the piston based on temperature estimations.

Abstract: A controller (an engine controller 100) feeds a fuel into a cylinder 11 through a fuel feeder (including a fuel injection valve 53 and a fuel feeding system 54) when the cylinder 11 is in an intake stroke and a compression stroke and if an engine body (an engine 1) is both in a cold running phase and under a heavy load. The engine body at or below a predetermined temperature is in the cold running phase. The load applied to the engine body is heavy when the engine body is under at least a predetermined load. The controller also lowers the upper limit of the charging efficiency of the engine body as the vaporization rate of the fuel fed into the cylinder decreases.

Abstract: An apparatus for removing a poison of a lambda sensor includes: a lambda sensor detecting an oxygen concentration included in an exhaust gas; and a control unit differentiating a heating temperature and a heating time to remove poison from the lambda sensor depending on a lambda signal output from the lambda sensor when a heating condition of the lambda sensor and an overrun section of an engine are satisfied. By heating the lambda sensor depending on the magnitude of the lambda signal output from the lambda sensor, the lambda sensor may be inhibited from being degraded by combusting the material poisoned to the electrode of the lambda sensor and the failure of the lambda sensor may be correctly determined.

Abstract: A removing poison apparatus of a lambda sensor includes: a lambda sensor detecting an oxygen concentration included in an exhaust gas; and a control unit differentiating a heating temperature and a heating time to remove poison of the lambda sensor depending on a lambda signal output from the lambda sensor in an overrun condition of the engine. By heating the lambda sensor depending on the magnitude of the lambda signal output from the lambda sensor, the lambda sensor may be inhibited from being degraded by combusting the material poisoned to the electrode of the lambda sensor and the failure of the lambda sensor may be correctly determined.

Abstract: An O2 sensor has a sensor element, which includes a solid electrolyte layer and a pair of electrodes. The solid electrolyte layer is held between the electrodes, which includes an atmosphere side electrode and an exhaust side electrode. A constant current circuit is installed in an electric path, which connects between the atmosphere side electrode and a ground, to induce a flow of a predetermined constant electric current between the electrodes through the solid electrolyte layer. When the sensor element generates an electromotive force, the constant current circuit conducts an electric current, which is generated while using the electromotive force of the sensor element as an electric power source, to induce the flow of the predetermined constant electric current between the electrodes in an electromotive force range, which is equal to or larger than an electromotive force of the sensor element generated at a stoichiometric air-to-fuel ratio.

Abstract: The adaptive pitch control system for wind generators is utilized in variable speed doubly fed induction generator (DFIG) systems. An adaptive neural network generates optimized controller gains for pitch control. The pitch controller parameters are generated using intelligent differential evolution, a type of genetic algorithm. A back propagation neural network is trained using the generated pitch controller parameters, thereby tuning the weights of the network according to the system states in a variable wind speed environment.

Abstract: A method/control unit for detecting a voltage offset in a range of a voltage-lambda characteristic curve of a two-point lambda sensor in an engine exhaust gas duct as to a reference voltage-lambda characteristic curve of the two-point lambda sensor, which is part of a controlled system for adjusting an air-fuel mixture supplied to the engine, a characteristic curve deviation of voltage-lambda characteristic curve to the reference characteristic curve being corrected at ?=1, so that a change in the air-fuel mixture composition toward ?=1 occurs, starting from a value pair to be checked on the reference characteristic curve, with a lambda and a voltage to be checked, the actual value of lambda being inferred from the change in the mixture composition until reaching ?=1. The method/control unit permit determining and compensating a voltage offset of a two-point lambda sensor conditional upon aging or manufacturing tolerances.

Abstract: A hybrid vehicle intermittently operates and stops an engine, travels through control over torque generated by the engine and torque generated by a second motor generator, causes a fuel vapor gas purge system to carry out purging of fuel vapor gas when a predetermined condition, including a condition that a coolant temperature is higher than or equal to a permissible temperature, is satisfied, and sets the permissible temperature to a value lower when a specific driving operation state that includes a state where the number of times of accelerator operation per unit time is higher than or equal to a threshold has been detected than when the specific driving operation state has not been detected. When the specific driving operation state has been detected, the hybrid vehicle increases the updating rate of a concentration learned value of fuel vapor gas, and decreases the rate of increase in target purge rate.

Abstract: A system according to the principles of the present disclosure includes a temperature estimation module and a fuel control module. The temperature estimation module estimates a piston temperature associated with a cylinder based on engine operating conditions. The fuel control module controls at least one of injection timing associated with the cylinder, injection pressure associated with a cylinder, injection location associated with a cylinder, and a number of injections per engine cycle associated with the cylinder based on the piston temperature.

Abstract: In order to relief a sudden change of engine sound during the transition to recovery control of a particulate removing filter or during returning from the recovery control, a system of treating exhaust gas of an engine includes an exhaust-gas particulate removing filter in an exhaust path, closes down the opening of an inlet throttle valve or an exhaust throttle valve to a recovery opening smaller than a normal opening during recovery of the particulate removing filter, and returns the opening from the recovery opening to the normal opening after the recovery of the particulate removing filter. The opening of the inlet throttle valve or the exhaust throttle valve during the closing process from the normal opening to the recovery opening and during the returning process from the recovery opening to the normal opening is changed at a gradually decreasing or gradually increasing rate of change of the opening.

Abstract: An alcohol concentration sensor detects an alcohol concentration in fuel that is supplied to an internal combustion engine. A fuel injection quantity is controlled in accordance with a detection value of the alcohol concentration that is detected by the alcohol concentration sensor. When a temperature of the fuel, which is detected by a fuel temperature sensor or estimated from intake air temperature etc., is equal to or lower than a predetermined limit temperature, the detection value of the alcohol concentration, which is detected by the alcohol concentration sensor, is memorized as a memorized value of the alcohol concentration. When the temperature of the fuel is higher than the predetermined limit temperature, the fuel injection quantity is controlled by using the memorized value of the alcohol concentration instead of using the detection value, which is currently detected by the alcohol concentration sensor.

Abstract: An engine system may include a fuel and air supply circuit and an exhaust circuit, a temperature sensor mounted on an exterior of the engine and an oxygen sensor located in the exhaust circuit. The fuel and air supply circuit may include a throttle body mounted on the engine and having a throttle valve to control the flow rate of air delivered to the engine, a fuel injector carried by the throttle body to deliver fuel to the engine and a fuel rail carried by at least one of the throttle body and the fuel injector and having an input to receive a supply of fuel and an outlet through which fuel is routed to the fuel injector. An engine control unit may be communicated with these components to control the fuel and air mixture provided to the engine as a function of the temperature and oxygen sensor outputs.

Abstract: An analysis tool which extracts all the available parameter identifications (i.e. PIDS) from a vehicle's power train control module for diagnostic decisions. This is done by checking these PIDS and other information (e.g., calculated PIDS, Break Points, charts and algorithms) in three states; key on engine off, key on engine cranking, key on engine running. In all three modes the tool is comparing the live data from PIDS and voltage to the other information (e.g, Break Points). If any of this data are outside the programmed values a flag is assigned to the failure or control problem. The relationship between a particular PID and its associated preprogrammed value(s) may be indicated by a light. The depth of the problem (if any) is conveyed by the color of the light. Also included are tests/charts for fuel trim, engine volumetric efficiency, simulated injector, power, catalyst efficiency, and engine coolant range.

Abstract: In the calibration of a lambda sensor (26), inaccuracies occur during a fuel cut-off overrun phase depending on the temperature. A method is proposed for correcting an output signal of a lambda sensor (16) of an internal combustion engine (1), having the following steps: detection of a fuel cut-off overrun phase of the internal combustion engine (1), sensing of an exhaust-gas composition by the lambda sensor (16) during the fuel cut-off overrun phase, sensing of a temperature which represents a measure of the intake air of the internal combustion engine (1), calibration of the lambda sensor (16) based on the second temperature.

Abstract: A system for an internal combustion engine of a vehicle is disclosed. In one example, characteristics of an oxygen sensor are a basis for determining degradation of a temperature sensor. In this way, the system can provide redundant exhaust gas temperature sensing.

Abstract: In a diesel engine 10 equipped with a fuel injection device 50 having a fuel supply pump 53 for pressingly sending a fuel, a common rail 52 for accumulating the fuel pressingly sent from the fuel supply pump, injectors 51 for injecting the fuel into a cylinder by an electronic control, a coolant water temperature sensor 64 for detecting an engine coolant water temperature and a fuel injection quantity map for calculating a target common rail pressure, total amount of injections, the number of multistage injection, the respective injection quantity and the respective injection quantity timing, the diesel engine 10 comprises a total injection quantity increasing means for increasing the total amount of injections in the injection quantity control arithmetic means and an injection number reduction avoidance means for avoiding that the number of multistage injections are changed by the total injection quantity increasing means when the engine is transferred to a cold state to a warming state.

Abstract: A fuel control system that includes a fuel injector control module that selectively applies a power source to a coil of a fuel injector. The fuel control system also includes a current determination module that selectively measures current flowing through the coil. The fuel control system also includes a fuel temperature estimation module that selectively calculates a resistance of the coil based on the measured current and a voltage value of the power source and that determines an estimated fuel temperature based on the resistance. The fuel injector control module controls operation of a fuel system based on the estimated fuel temperature.

Abstract: Temperature of an electric power device of a hybrid transmission is managed based upon device temperatures and power flow, ambient temperature, and a cooling circuit flow rate.

Abstract: Methods and apparatus are disclosed for operation of a multiple fuel engine, which runs on a combination of two or more fuels. An electronic control unit (ECU) may be connected to the existing components of an engine system in order to control operation of the multiple fuel engine. The engine system may be mechanically governed or electronically controlled. The ECU inputs operating characteristics of the engine system, determines governing characteristics for multiple fuel operation based on the operating characteristics, and controls the amounts of fuel delivered to the engine based on the governing characteristics. In a preferred embodiment, a dual fuel engine operates using diesel as a first fuel and natural gas as a second fuel. The operating characteristics may include engine speed, throttle position, engine exhaust temperature, gas pressure of the second fuel, gas temperature of the second fuel, boost pressure of an intake manifold, or engine coolant temperature.

Abstract: A throttle operation is performed after an internal combustion engine is started. Then, temperature of a catalyst is obtained based on a signal output from a temperature sensor fitted to the catalyst. It is then determined whether the temperature obtained is equal to or higher than the activation temperature. If it is determined that the temperature of the catalyst has not reached the activation temperature, the throttle operation continues. On the other hand, if it is determined that the temperature of the catalyst is equal to or higher than the activation temperature, the non-throttle operation is performed instead of the throttle operation.

Abstract: Inhibiting uncontrolled regeneration of a particulate filter fluidly coupled to an exhaust manifold of an internal combustion engine may comprise reducing an oxygen concentration of exhaust gas supplied to the particulate filter if active regeneration of the particulate filter is in progress and rotational speed of the engine speed thereafter drops to an idle speed range from an elevated rotational speed that is greater than the idle speed range. Reducing the oxygen concentration of the exhaust gas supplied to the particulate filter may include any one or combination of reducing the oxygen concentration of intake air supplied to the intake manifold, reducing the air portion of the air-to-fuel ratio of the air-fuel mixture supplied to the engine and removing oxygen from the exhaust gas supplied to the particulate filter.

Abstract: The invention relates to a fuel injection system comprising a fuel reservoir to which fuel is fed via at least one first pump and from which fuel is discharged via injectors. The invention is characterized in that the feed pressure of the first pump is adjusted depending on fuel temperature and evaporative behavior of the fuel.

Abstract: To prevent RPM decrease, misfire, and engine stall by refraining from correcting, the amount of fuel to shift an air-fuel ratio toward a lean side to the extent of exceeding a combustion limit when the internal combustion engine operates at a low load, a control apparatus is provided for controlling operation of an internal combustion engine. The apparatus includes an air-fuel ratio state determiner, a characteristic retainer and a fuel correction amount calculator, in which a coolant temperature coefficient of a coolant temperature coefficient characteristic is set to be smaller than a constant value in a region where a coolant temperature is lower than a constant temperature.

Abstract: A control apparatus for an internal combustion engine can avoid overcorrection at a lean side of air fuel ratio learning correction by unburnt fuel in a blowby gas, and prevent rotational speed reduction and engine stall during air fuel ratio open-loop control after restarting of the engine. A temperature detecting section detects the temperature of the engine based on signals of various sensors, and an air fuel ratio learning correction value changing section updates an air fuel ratio learning correction value in accordance with the engine operating condition. When the engine is stopped with its temperature having not yet reached a predetermined value after started from a cold state thereof, an amount of update of the air fuel ratio learning correction value at a lean side is set in such a manner that the lower a temperature parameter immediately before engine starting, the smaller does the amount of update become.

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: When an internal combustion engine is in a low load and low rotation operation, and also an elapsed time after the starting of engine operation is less than a predetermined period of time, a heater heating an air-fuel ratio sensor is turned OFF, to stop an air-fuel ratio feedback control. When the internal combustion engine is in the low load and low rotation operation after the predetermined period of time has elapsed, a low voltage is applied to the heater and also a gain is lowered, to perform the air-fuel ratio feedback control.

Abstract: A temperature of an oxygen concentration detector generating an electromotive force according to a difference between oxygen concentration in an engine exhaust gas and oxygen concentration in the atmosphere, is detected, and coefficients in a transformation for converting the electromotive force to a value having a characteristic linear to an air-fuel ratio is modified according to the temperature.

Abstract: A first oxygen sensor is mounted on an exhaust pipe. An ECU determines an electric power to be fed to a sensor heater, by a heater control quantity calculating block, in accordance with a difference between an actual impedance and a target impedance calculated by a running condition determining block and a specific gas sensitivity priority determining block. As a result, the detection sensitivity of the oxygen sensor to a rich component or a lean component is improved according to the running condition. This improved output is detected by an output detecting block and reflected on the air/fuel ratio control so that an air/fuel ratio is controlled thereby.

Abstract: A method is provided for easily avoiding undesirable effects on various physical values due to the change in temperature of a motor for driving a throttle valve without causing secondary problems. A technique is also provided for measuring the temperature of the motor electrically. The method uses a compensation device for correcting the power supply to the motor by detecting the impedance of the motor windings and/or the change in the motor temperature. The temperature of the motor is estimated from the current and voltage to the motor.

Abstract: A method and apparatus for controlling the operation of an internal combustion engine to reduce the presence of free oxygen in the exhaust gas of the engine. The method and apparatus provides for the internal combustion engine to be operated with a fuel-to-air ratio in excess of the stoichiometric ratio such that the exhaust gas from the internal combustion engine is devoid or substantially devoid of all free oxygen and excess unburned hydrocarbon fuel is expelled with the exhaust gas from the engine.

Abstract: A method is introduced for compensating for mismatches of the precontrol of a fuel metering for an internal combustion engine[,].A [−a] regulation being superimposed on the precontrol[,].At [− and at] least one correction quantity being formed, from the behavior of the regulation at high temperatures of the internal combustion engine, which influences the fuel metering even at low temperatures of the internal combustion engine in a supplementing [way] manner to the superimposed regulation for compensating for the mismatches[, and − at] At low temperatures a further correction quantity is formed which acts upon the fuel metering, and [−] whose effect at low temperatures of the internal combustion engine is greater than at high temperatures.

Abstract: An outboard motor includes a sensor assembly having a housing with a sensor chamber, a sensor having a sensor element exposed to the sensor chamber, and a sleeve disposed in a passage extending from a combustion chamber of the outboard motor to the sensor chamber. The sleeve can have three flanges supporting the sleeve within the passage. Additionally, the sleeve can have an extension so as to allow the overall length of the sleeve to be varied in accordance with the desired resonance frequency of the sensor chamber. An engine of the outboard motor can also include a control system configured to control an air/fuel ratio of fuel charges delivered to a combustion chamber within the engine based on an output of the combustion condition sensor when the engine is in a first operational state and to control the air/fuel ratio, irrespective of the output of the combustion condition sensor, when the engine is in the second operational state.

Abstract: The performance of a compression ignition internal combustion engine is improved by optimizing excess air ratio (lambda) and/or intake air charge temperature (ACT) on a full time, fall range basis. The basic procedure is to first determine the desired or optimum lambda and then to control ACT and intake manifold absolute pressure (MAP) to maintain them at the optimum values for the fuel quantity required at a particular operating point. This approach allows control of both temperature and pressure of the air entering the engine. Full range control requires that lambda and ACT be controlled both upward and downward to achieve optimal engine performance. Control of both lambda and ACT is further enhanced through the use of a supercharger with adjustable input power installed in series with a standard turbocharger compressor of the engine.

Abstract: A self-adapting method of controlling the mixture ratio of an injection system, of an internal combustion engine. In each operating state of the engine and for each injector, the method determines a nominal quantity of fuel to be injected as a function of a number of engine parameters and operating conditions, an operating parameter as a function of a signal representing exhaust gas composition and of a proportional-integral regulating function and hot and cold correction coefficients indicating a correction to be made to the nominal quantity of fuel to take into account the effect on injection of different engines and different injection systems during hot and cold engine operation.

Abstract: The performance of a compression ignition internal combustion engine is improved by optimizing excess air ratio (lambda) and/or intake air charge temperature (ACT) on a full time, full range basis. The basic procedure is to first determine the desired or optimum lambda and then to control ACT and intake manifold absolute pressure (MAP) to maintain them at the optimum values for the fuel quantity required at a particular operating point. This approach allows control of both temperature and pressure of the air entering the engine. Full range control requires that lambda and ACT be controlled both upward and downward to achieve optimal engine performance. Control of both lambda and ACT is further enhanced through the use of a supercharger with adjustable input power installed in series with a standard turbocharger compressor of the engine.

Abstract: The present invention provides a flexible fuel compensation system for determining the percent alcohol content of fuel in a flexible fueled vehicle at the instance of fueling and in an open loop operating mode. According to the invention, two estimated percent alcohol content values are calculated based on the old fuel mixture's alcohol content and two fueling possibilities. A first value is calculated for the possibility that E85 fuel was added to the tank and a second value is calculated for the possibility that E0 fuel was added to the tank. If the inferred ethanol content increases above a positive threshold during closed loop operation, the system assumes that E85 fuel has been added to the tank. Conversely, if the inferred ethanol content decreases below a negative threshold, the system assumes that E0 fuel was added to the tank.

Abstract: An initial power feed quantity to be provided at the start to an electric heater equipped to an air-fuel ratio sensor is set corresponding to the temperature of a sensor element, and at the same time, the increase control time for increasingly changing the power feed quantity from said initial power feed quantity to the maximum power feed quantity is set corresponding to the temperature of the sensor element, and according to said initial power feed quantity and said increase control time, the power feed quantity to said electric heater is increased gradually from the start.

Abstract: A feed back control system and method for direct injected engines, particularly useful in marine applications to avoid excessive hunting due to the close proximity of the sensor to the fuel injector. Both injection initiation and duration are controlled under most operating conditions. However, under certain conditions such as when only small corrections in the air fuel ratio are required the control is initially maintained by adjusting the injection timing.

Abstract: An air-fuel ratio control system for an internal combustion engine is provided, which includes an oxygen concentration sensor arranged in the exhaust system and having an output characteristic that an output thereof is substantially proportional to concentration of oxygen present in exhaust gases from the engine. An ECU is responsive to the output of the oxygen concentration sensor, for carrying out feedback control of the air-fuel ratio of a mixture supplied to the engine so as to make the air-fuel ratio equal to a desired air-fuel ratio. An activated state of the oxygen concentration sensor is detected. Correction of the air-fuel ratio of the mixture by the feedback control is limited, depending upon the detected activated state of the oxygen concentration sensor.

Abstract: The present invention is an engine control for an internal combustion engine having at least one combustion chamber and an air/fuel charging system for delivering an air and fuel charge to the combustion chamber for combustion therein. The control includes an oxygen sensor associated with the combustion chamber, the sensor providing feedback data based upon the air/fuel ratio of the charge supplied to the combustion chamber. The control also includes at least one sensor for sensing a condition other than the air/fuel ratio in the combustion chamber which affects the output of the oxygen sensor. The control adjusts the air/fuel ratio of the charge delivered to the combustion chamber towards a target value based upon the output of the oxygen sensor, the control arranged to adjust the target value based upon the output of the at least one sensor sensing an operating condition other than the air/fuel ratio.

Abstract: The present invention provides a method of compensating for an erroring sensor in a flexible fuel compensation control system for a flexible fueled vehicle. The methodology provides a method for identifying preselected operating conditions without the output of the erroring sensor. As such, the flexible fuel compensation control system may still be employed to ensure vehicle drivability even in the absence of input from an erroring sensor.

Abstract: An engine feedback control for an internal combustion engine having at least two combustion chambers is disclosed. When a sensor detects a high engine temperature condition of the engine, the feedback control changes the air/fuel ratio of the air and fuel supplied to each combustion chamber in a manner which prevents operation of any combustion chamber in a disabling range.

Abstract: An air/fuel ratio control apparatus for executing auxiliary control of an air/fuel ratio by compensating an injected fuel amount set by a control system for maintaining the air/fuel ratio at a preset value. The air/fuel ratio control apparatus includes a state detecting unit for detecting a plurality of physical values which can be measured at low temperature and which show a state of an engine, an air/fuel ratio estimating unit for receiving a plurality of physical values detected by the state detecting means as input parameters and for estimating the air/fuel ratio using a neural network, and a compensatory fuel amount calculating unit for calculating a compensatory fuel amount for the injected fuel amount from the estimated air/fuel ratio. Here, low temperature refers to a temperature at which an air/fuel sensor cannot operate.

Abstract: An apparatus controls power supplied to a heater of an air-fuel-ratio sensor in consideration of the radiant heat from a catalytic converter. A map showing a relationship between power supplied to the heater and engine operating conditions is prepared on the assumption that radiant heat from the converter never affects the temperature of the sensor. Another map showing the same relationship is prepared on the assumption that radiant heat from the converter, which is new, affects the temperature of the sensor. A difference .DELTA.Qij=Q2ij-Q1ij is calculated under the same engine operating conditions, where Q1ij is power supplied to the heater with radiant heat from the converter affecting the temperature of the sensor and Q2ij is power supplied to the heater with radiant heat from the converter not affecting the temperature of the sensor. At the same time, a deterioration index DR of the converter is calculated. The deterioration index DR is used to determine a coefficient .alpha..

Abstract: An air-cooled multi-cylinder engine including two temperature sensors each attached to different cylinders. The temperature difference between the two cylinders is detected by the temperature sensors. The air-fuel ratio in each cylinder is made the stoichiometric air-fuel ratio by decreasing the amount of fuel fed into higher temperature cylinders and increasing the amount of fuel fed into lower temperature cylinders.