Abstract: A method for operating an internal combustion engine working according to the Otto principle, in which fuel, particularly gasoline, is injected directly into a combustion chamber and is inflamed by self-ignition. A characteristic quantity characterizing the stability of combustion of an air/fuel mixture located in the combustion chamber is ascertained, and, as a function of the characteristic quantity, a residual gas proportion in the cylinder associated with the combustion chamber is set, in particular minimized, the residual gas proportion being reduced, preferably iteratively, as long as the characteristic quantity does not fall below a specifiable stability boundary.

Abstract: A system for controlling fuel to an engine to minimize emissions in an exhaust of the engine. There may be a controller connected to an actuator, for example a fuel control actuator, of the engine and to emissions sensors, such as an NOx and/or PM sensor, proximate to an exhaust output of the engine. The controller, for example a speed controller, may have an input connected to an output of a pedal or desired speed setting mechanism. A speed sensor at a power output of the engine may be connected to an input of the controller.

Abstract: A system and method is provided to reduce the occurrence of engine knock for engines that utilize a dual-fuel fumigation system. Typically, dual fuel systems inject a gaseous-fuel flow into the air intake stream of a diesel engine. This results in more complete combustion within the engine as well as reduced diesel fuel usage. Such dual fuel systems are susceptible to engine knocking due to premature detonation of the gaseous fuel air intake mixture that is often caused by sudden changes to the operating conditions of the engine. The present system utilizes a knock sensor to identify early stages of such engine knocking. To eliminate such engine knocking conditions, the system temporarily interrupts the gaseous fuel flow to resume operation in full diesel mode. The gaseous fuel flow is then reestablished based on the present operating conditions of the engine.

Abstract: The method of the present invention is adapted to protect an exhaust aftertreatment system by preventing the system from becoming clogged and/or damaged during periods of light engine load. According to a preferred embodiment, the present invention protects the exhaust aftertreatment system by increasing the load on the engine during periods of light engine load and/or low exhaust temperature.

Abstract: A fuel supply assembly is provided that may allow for use of vaporized fuel to power an engine and enhance fuel efficiency. The fuel supply assembly may include a vaporizing tank, a heating source, a temperature control and a monitoring and control system configured to control intermixing of ambient air and vaporized gasoline to maintain a desired hydrocarbon level in an exhaust.

Abstract: A common fuel injection amount is calculated for the cylinders of a first cylinder group, which performs a rich burn process, and the cylinders of a second cylinder group, which performs a lean burn process. The calculated fuel injection amount is corrected with an air-fuel ratio learning value that is acquired beforehand during a stoichiometric operation. Intake valve lift amounts for the cylinders of the first and second cylinder groups are calculated in accordance with an engine speed and engine load. In compliance with the calculated values, a variable valve mechanism is driven, and fuel is ignited. When performing sulfur poisoning recovery of the Ox catalyst, the exhaust air fuel ratio control means change the intake air amount for each cylinder while providing substantially the same fuel injection amount for all cylinders.

Abstract: An engine control apparatus feedback-controls a mixture air-fuel ratio of air-fuel mixture supplied to each cylinder of the engine based on an exhaust air-fuel ratio detected by an air-fuel ratio sensor. The control apparatus further calculates an exhaust air-fuel ratio change rate at every predetermined interval and integrates an absolute value of the exhaust air-fuel ratio change rate. The control apparatus determines an abnormality in any one of engine cylinders when an integration value of the exhaust air-fuel ratio change rate exceeds a predetermined reference value.

Abstract: The internal combustion engine controller includes an oxygen concentration sensor outputting an electric signal having a value depending on an oxygen concentration in an exhaust gas flowing through an exhaust passage of an internal combustion engine, and a control unit controlling fuel injection amount depending on at least the electric signal, the control unit being capable of performing atmospheric learning to calibrate the oxygen concentration sensor. The control unit is configured to perform the atmospheric learning when a changing rate of the value of the electric signal is lowered from above a predetermined threshold rate to below the predetermined threshold rate after a time of start of cutoff of fuel supply to the engine.

Abstract: An air-fuel ratio control system includes: a catalyst; an A/F sensor provided upstream of the catalyst; an oxygen concentration sensor provided downstream of the catalyst; an output value estimation portion that estimates the output value of the oxygen concentration sensor using a model related to the catalyst and the oxygen concentration sensor; an integral value calculation portion that calculates an integral value of deviation being updated by integrating the difference between the actual oxygen concentration output value and the estimated output value; a correction value calculation portion that calculates a feedback correction value for the output value of the A/F sensor and a target air-fuel ratio at least based on the integral value of deviation; and an air-fuel ratio control portion that zeros a first deviation that is obtained by correcting the difference between the detected air-fuel ratio and the target air-fuel ratio, using the feedback correction value.

Abstract: A method and associated arrangement for achieving an adjusted engine setting utilizing engine output and/or fuel consumption. An engine that consumes fuel is run. Fuel consumption and/or engine operation output is determined. A value is determined utilizing the determined fuel consumption and/or the determined engine operation output. The engine setting is adjusted to cause the determined value to change toward a desired value.

Abstract: The temperature of an exhaust gas flowing through an exhaust passage 3 is estimated or detected, and the temperature of an active element of an exhaust gas sensor 8. (O2 sensor) is controlled at a predetermined target temperature by a heater using the estimated or detected temperature of the exhaust gas. For estimating the temperature of the exhaust gas in the vicinity of the exhaust gas sensor 8, the exhaust passage 3 extending up to the exhaust gas sensor 8 is divided into a plurality of partial exhaust passageways 3a through 3d, the temperatures of the exhaust gas in the partial exhaust passageways 3a through 3d are estimated successively from an exhaust port 2 of an engine 1. The temperature of the exhaust gas is estimated according to an algorithm which takes into account a heat transfer between the exhaust gas and passage-defining members 6a, 6b, 7 which define the exhaust passage 3 and a heat radiation from the passage-defining members into the atmosphere.

Abstract: A valve timing correction control apparatus for an internal combustion engine is provided. The engine includes a plurality of banks and variable valve operating mechanisms disposed at the respective banks for variably controlling valve timings of intake valves separately at the respective banks. The valve timing correction control apparatus comprises air/fuel ratio sensors provided to exhaust systems of the respective banks, and a control unit that corrects the valve timings of the intake valves at the respective banks in accordance with deviations of air/fuel ratios detected by the respective air/fuel ratio sensors. A valve timing correction control method is also provided.

Abstract: A method and device for controlling an internal combustion engine are provided. A first quantity characterizing the actually injected fuel amount and a second quantity characterizing the desired amount of fuel to be injected are determined on the basis of performance characteristics. The first quantity is compared to the second quantity. This comparison is used to define a first correction value for correcting a fuel amount and a second correction value for correcting an air amount. The first correction value is limited to a maximum value.

Abstract: An engine 1 provided with a fuel injection mechanism (a fuel injection system 18 and an FI control unit 41) that supplies fuel of arbitrary quantity into a combustion chamber 9 and a variable valve mechanism (an intake valve 14, an exhaust valve 15, hydraulic electromagnetic valve drive units 16, 17 and a valve event control unit 40) that varies the ratio of burned gas and air-fuel mixture in the combustion chamber 9 for combusting fuel by compression self ignition, is controlled so that a deviation ?T between combustion initiation temperature and peak temperature after combustion in the combustion chamber 9 is converged in a predetermined range.

Abstract: A marine engine has an exhaust system including a catalyst cooled by a flow of coolant, a coolant injector that injects coolant into the flow of exhaust at a point downstream of the catalyst, and a sensor arranged to sense a characteristic of the flow of exhaust, such as oxygen or carbon monoxide level. The engine controller is configured to control an air/fuel ratio of the engine as a function of the sensed exhaust flow characteristic.

Abstract: A control system for estimating the performance of a compressor is disclosed. The control system has a compressor fluidly connected to an inlet manifold of a power source. The control system also has a power source speed sensor to provide an indication of a rotational speed of the power source, an inlet pressure sensor to provide an indication of a pressure of a fluid within the inlet manifold, an inlet temperature sensor to provide an indication of a temperature of the fluid within the inlet manifold, an atmospheric pressure sensor to provide an indication of an atmospheric pressure, and a control module in communication with each of the sensors. The control module is configured to monitor an engine valve opening duration and an exhaust gas recirculation valve position, and estimate a compressor inlet pressure based on the provided indications, the monitored duration, and the monitored position.

Abstract: In an engine having a premixed combustion mode, an EGR flow rate estimating precision is deteriorated at a transient time, and a torque fluctuation and an exhaust gas deterioration are caused. In an engine control apparatus having a premixed combustion mode and a diffusion combustion mode, a sensor detecting an EGR flow rate is arranged in an EGR flow path of the engine, and a cylinder state of the engine is estimated by using an output value of the sensor detecting the EGR flow rate at a time when the engine is in the premixed combustion mode. Since it is possible to accurately detect the EGR flow rate at the transient time and feed back the EGR flow rate at a high response, it is possible to prevent a torque fluctuation and an exhaust gas deterioration.

Abstract: A method for controlling internal combustion engine emissions, including the steps of reading signals from sensors in an engine exhaust manifold and catalytic converter exhaust, an upstream one of the sensors being provided with an air-fuel mixture setpoint, comparing signal values with previous average values and automatically adjusting the air-fuel mixture set point to vary the fuel mixture fed to the engine.

Abstract: A system for a vehicle comprising of an engine including a first cylinder group and a second cylinder group; a linear exhaust gas sensor coupled exclusively to the first cylinder group; a switching exhaust gas sensor coupled exclusively to the second cylinder group; and a controller configured to operate the engine in at least a first mode and a second mode, where in the first mode the first and second cylinder groups combust air and fuel, where in the second mode at least one of the first and second cylinder groups combusts air and injected fuel and the other one of the first and second cylinder groups pumps air without injecting fuel, and where the controller is further configured to estimate torque of the engine in each of the first and second modes of operation based on the air-fuel ratio of the first cylinder group and the air-fuel ratio of the second cylinder group independent of the switching sensor and dependent on the linear sensor.

Abstract: A system and method is provided to reduce particulate and NOx emissions from diesel engines through the use of a duel-fuel fumigation system. The system injects a gaseous-fuel flow into the air intake stream of a diesel engine. This results in more complete combustion within the engine as well as reduced diesel fuel usage, which each work to reduce emission outputs of the engine. As presented, the system is operative to meter the gaseous-fuel flow into the diesel engine based on one or more engine parameters such as, for example, exhaust gas temperature, exhaust oxygen levels, engine speed and/or engine load. Monitoring one or more engine parameters allows fine-tuning the flow of gaseous fuel into the engine and thereby prevents loss of engine power at high-end loads while maintaining favorable emission outputs over substantially the entire operating range of the engine.

Abstract: Fuel properties estimating apparatus for an internal combustion engine includes a controller to determine an estimated component concentration of a component in a fuel. The controller calculates an air-fuel correction quantity in accordance with an actual air fuel ratio of the engine; and calculates an air-fuel ratio sensitivity correction quantity from the air-fuel ratio correction quantity and a fuel properties correction quantity calculated from a most recent value of the component concentration. The controller then determines a new value of the estimated component concentration in accordance with the air-fuel ratio sensitivity correction quantity.

Abstract: Variable valve control method and apparatus for an internal combustion engine provided with a variable valve mechanism that varies an operating characteristic of an intake valve, for controlling a gas amount passing back through the intake valve by variably controlling the operating characteristic. A storage section stores previously a correlation between a value equivalent to an opening area of the intake valve and a valve passing gas amount, corresponding to predetermined effective cylinder capacity. A conversion section converts that value equivalent into the valve passing gas amount by referring to the correlation. A correction section corrects the value equivalent based on a ratio between the converted valve passing gas amount and a requested valve passing gas amount.

Abstract: A method of regulating an internal combustion engine, in particular involving a lean-burn mode of operation, for achieving predeterminable nitrogen oxide emission values from the internal combustion engine, wherein the actual value of the ?-value or the calorific value of a fuel-air mixture to be burnt in the internal combustion engine or a nitrogen oxide emission value is detected, preferably directly measured, and is regulated in dependence on a parameter which is characteristic of quality and/or quantity of the fuel supplied or in dependence on the power (P) delivered by the internal combustion engine.

Abstract: In a multipurpose engine with a reduced or limited displacement adapted for use in a portable work machine or the like, the engine includes a detecting element of a gas sensor for controlling an air-fuel ratio. Damage or degradation of the detecting element due to vibration from the engine is reduced or eliminated. To achieve this, a supporting device having a vibration-damping-function is provided for supporting the gas sensor or the gas sensor unit containing the gas sensor. The supporting device permits the gas sensor or the gas sensor unit to move by an amount equal to or less than a predetermined extent of movement of the engine, so that the transmission of vibration from the engine directly to the gas sensor is reduced or eliminated.

Abstract: A method of regulating an internal combustion engine, in particular involving a lean-burn mode of operation, for achieving predeterminable nitrogen oxide emission values from the internal combustion engine, wherein the ?-value of a fuel-air mixture to be burnt in the internal combustion engine or an equivalent engine parameter in a defined relationship with said ?-value is regulated in dependence on the amount of fuel supplied per unit of time or in dependence on the fuel energy supplied per unit of time (Qzu).

Abstract: A method and a device are described for controlling an internal combustion engine. On the basis of the comparison of a setpoint value with an actual value for a variable that characterizes the supplied oxygen quantity, an actuating variable is predefined for controlling an actuating element that influences the fuel quantity conducted to the internal combustion engine and/or the oxygen quantity supplied to the internal combustion engine. The actual value and/or the setpoint value are/is normalized to a reference value.

Abstract: An internal combustion engine system includes an intake manifold, a combustion chamber, an exhaust manifold and exhaust gas recirculation apparatus for recirculating a portion of the exhausted gases from the exhaust manifold to the intake manifold. An estimate intake manifold oxygen concentration is determined from the air fraction within the intake manifold which is determined from an engine system model that provides interdependent air mass fractions at various locations within the engine system.

Abstract: A fuel supply assembly providing vaporized fuel to an engine wherein a quantity of liquid gasoline fuel is controllably heated for a desired vapor emission from the liquid fuel, and a conduit arrangement conducts the vapor, intermixes it with ambient air and conveys the intermixture to the engine's combustion chamber. A sensor in the engine exhaust monitors the hydrocarbon content of the exhaust and control valving controls the vapor to air intermixture in response to the monitor for maintaining a desired intermixture that produces the desired hydrocarbon content.

Abstract: An intake port (4) is connected to a combustion chamber (6) of an internal combustion engine (1) via an intake valve (15), and a volatile liquid fuel is injected from a fuel injector (21) provided in the intake port (4). The controller (31) calculates a suspension ratio in the combustion chamber (5) of the injected fuel according to the particle diameter of the injected fuel (52–56), calculates an amount of fuel burnt in the combustion chamber (6) based on the suspension ratio (57), calculates a target fuel injection amount based on the burnt fuel amount (75, 76), and controls a fuel injection amount of the fuel injector (21) based on the target fuel injection amount (76). Precise fuel injection control can be performed without performing adaptation experiments, based on particle diameter data for different fuel injectors by taking the particle diameter as a parameter.

Abstract: A control apparatus is provided for eliminating a slippage in control timing between the input/output of a controlled object, even when the control object exhibits a relatively large dynamic characteristic such as a phase delay, a dead time, or the like, to improve the stability and the controllability of the control. The control apparatus comprises a state predictor for calculating a predicted value of a value indicative of an output of a controlled object based on a prediction algorithm, and a DSM controller for calculating a control input to the controlled object based on one modulation algorithm selected from a ? modulation algorithm, a ?? modulation algorithm, and a ?? modulation algorithm for controlling the output of the controlled object in accordance with the calculated predicted value.

Abstract: An emission control device for use with stationary or mobile gas-fueled internal combustion engines is described, which is placed in the fuel supply line and operates with full fuel authority. An oxygen sensor measures exhaust oxygen content. The valve internally houses a programmable microprocessor, a pressure transducer and a fuel flow conduit throttled by a balanced poppet valve. Signals to the microprocessor from the oxygen sensor, the pressure transducer indicating outflow gas pressure cause the microprocessor to motivate an actuator to move the valve within the gas stream and thus regulate the outlet pressure and also the gas flow rate to maintain a desired air/fuel ratio to the engine and keep exhaust emissions at an optimum level consistent with the engine operating load requirements and characteristics. Finite incremental control of valve position, preferably assisted by an internal position transducer, permits close control of the exhaust emissions.

Abstract: Fuel properties estimating apparatus for an internal combustion engine includes a controller to determine an estimated component concentration of a component in a fuel. The controller calculates an air-fuel correction quantity in accordance with an actual air fuel ratio of the engine; and calculates an air-fuel ratio sensitivity correction quantity from the air-fuel ratio correction quantity and a fuel properties correction quantity calculated from a most recent value of the component concentration. The controller then determines a new value of the estimated component concentration in accordance with the air-fuel ratio sensitivity correction quantity.

Abstract: A fuel supply assembly is provided that may allow for use of vaporized fuel to power an engine and enhance fuel efficiency. The fuel supply assembly may include a vaporizing tank, a heating source, a temperature control and a monitoring and control system configured to control intermixing of ambient air and vaporized gasoline to maintain a desired hydrocarbon level in an exhaust.

Abstract: A failure detection apparatus for an internal combustion engine includes failure detecting means (S22-S30) for detecting abnormality of fresh air quantity detecting means (air flow sensor) based on the result of comparison between a fresh air quantity detected by the fresh air quantity detecting means (air flow sensor) and a fresh air quantity reference value set by fresh air quantity reference value setting means (S20), and exhaust flow rate adjusting means. The fresh air quantity reference value setting means sets the reference value (S16) in accordance with not only the operating state (engine speed Ne, fuel injection quantity Qf, etc.) of the engine but also a target adjustment amount (target throttle valve opening) set for the exhaust flow rate adjusting means by target adjustment setting means (S12, S14).

Abstract: A method for controlling an engine having both an electronically controlled inlet device, such as an electronic throttle unite, and an electronically controlled outlet device, such as a variable cam timing system is disclosed. The method of the present invention achieves cylinder air charge control that is faster than possible by using an inlet device alone. In other words, the method of the present invention controls cylinder air charge faster than manifold dynamics by coordination of the inlet and outlet device. This improved control is used to improve various engine control functions.

Abstract: For achieving a highest possible measuring accuracy of a circuit for measuring the internal resistance of an exhaust-gas sensor, a method and a circuit for measuring the internal resistance R1 (10) of an electrochemical cell (12) are provided for determining the temperature of an exhaust-gas sensor, especially of a motor vehicle. The circuit is provided with the objective to improve the control to a constant temperature to therefore also improve the performance of the exhaust-gas sensor. A measurement current I_Mess (20) is applied to the internal resistance R1 (10) of the electrochemical cell (12) and a resulting first voltage is detected. A switchover to a reference resistor R2 takes place from time to time or at regular time intervals. With a switchover to the reference resistor R2, the resulting second voltage is stored and thereafter is applied as a reference value for the measurement of the internal resistance R1 (10).

Abstract: An exhaust gas purifying system of the present invention comprises a first catalyst which contains a noble metal and reduces hydrocarbons contained in exhaust gas, and a second catalyst which is disposed downstream of the first catalyst and contains ?-zeolite. In the exhaust gas purifying system, a mixed gas having an air-fuel ratio of not less than 25 is burned in an internal combustion engine, and the internal combustion engine discharges the exhaust gas having an oxygen concentration of not less than 4% continuously or intermittently.

Abstract: The invention relates to a virtual sensor of exhaust emissions from a fuel-injection endothermic engine having a combustion chamber in each of its cylinders, a fuel injector serving each combustion chamber, and an electronic fuel-injection control unit. Advantageously, the virtual sensor includes an input interface receiving a signal from at least one pressure sensor for measuring the pressure inside at least one combustion chamber of the engine, a second input interface receiving signals from the electronic fuel-injection control unit, and a calculation block to provide estimates of the amounts of nitrogen compounds and particulates in the emissions based on the pressure and other relevant signals to the engine operation.

Abstract: A fuel supply assembly is provided that may allow for use of vaporized fuel to power an engine and enhance fuel efficiency. The fuel supply assembly may include a vaporizing tank, a heating source, a temperature control and a monitoring and control system configured to control intermixing of ambient air and vaporized gasoline to maintain a desired hydrocarbon level in an exhaust.

Abstract: An output signal from a downstream-side exhaust gas sensor is fed back into a fuel injection rate so that the air-fuel ratio of the exhaust gases flowing out from a catalyst may match a reference value. In this sub-feedback control process, the integral value of the deviation between the output signal of the downstream-side exhaust gas sensor and a reference value is calculated, and the resulting integral-data signal is smoothed. A learning value for compensating for the permanent error included in an air-fuel ratio signal from an A/F sensor is learnt from the integral-data signal generated by the above smoothing operation.

Abstract: A system and method is provided to reduce particulate and NOx emissions from diesel engines through the use of a duel-fuel fumigation system. The system injects a gaseous-fuel flow into the air intake stream of a diesel engine. This results in more complete combustion within the engine as well as reduced diesel fuel usage, which each work to reduce emission outputs of the engine. As presented, the system is operative to meter the gaseous-fuel flow into the diesel engine based on one or more engine parameters such as, for example, exhaust gas temperature, exhaust oxygen levels, engine speed and/or engine load. Monitoring one or more engine parameters allows fine-tuning the flow of gaseous fuel into the engine and thereby prevents loss of engine power at high-end loads while maintaining favorable emission outputs over substantially the entire operating range of the engine.

Abstract: An oxygen sensor deterioration diagnosis apparatus includes an oxygen sensor provided in an exhaust system of an internal combustion engine, an air-fuel ratio control unit for controlling an air-fuel ratio, an operation state detection unit for detecting an operation state of the internal combustion engine, an inversion period measurement unit for detecting an inversion period of an output signal of the oxygen sensor, an oxygen sensor deterioration diagnosis unit for performing a deterioration judgment by comparing the inversion period with a previously set judgment period, and a deterioration diagnosis inhibiting unit for inhibiting, when the operation state detection unit detects the operation state of the internal combustion engine having an influence on the inversion period, the measurement of the inversion period in a period of time of the detection.

Abstract: A method for operating an electronic controller of a motor vehicle, in particular of an engine controller, with which signal processing is carried out in order to control the operation of the motor vehicle and/or of the engine. The signal processing of the controller includes a filtering operation, the filtering operation being carried out as a function of the operating state of the motor vehicle and/or of the engine.

Abstract: There are provided a control apparatus capable of controlling a controlled object with reduce dead time in sign inversion between the input to and the output from one of ?? and ?? modulation algorithms, thereby attaining improved convergence of the output from the controlled object to a target value and improved controllability. An ECU of the control apparatus calculates a limiting value DSMVO2L of a reference input DSMVO2, as DSMVO2L=?1 when DSMVO2<?1, DSMVO2L=1 when 1<DSMVO2, and DSMVO2L=DSMVO2 in the other cases. By inputting the limiting value DSMVO2L to a ? ? modulation algorithm, a DSM output is calculated, according to which the air-fuel ratio of a mixture supplied to an internal combustion engine is controlled such that output from an oxygen concentration sensor converges to a target value.

Abstract: The present invention is a dual-stage fuel injection strategy for compression ignition engines in which 15-40% of the fuel is injected into the combustion chamber no later than about ?20 to ?30 CA ATDC and as early as IVC. The rest of the fuel is then injected in one or more fuel pulses, none of which start before about ?20 to ?30 CA ATDC. The fuel injected early in the compression stroke forms a lean mixture that burns with low soot and low NOx emissions. The combustion of that fuel serves to increase in-cylinder temperature such that the ignition delay of subsequent fuel injection pulses is short. This mode is utilized when it is predicted that a NOx spike is imminent. Various other alternative methods for reducing NOx spikes are also disclosed such as specialized EGR systems that can provide EGR with low manifold vacuum.

Abstract: An internal combustion engine exhaust device. The device includes a conduit element through which exhaust gases flow. The conduit element includes a housing for mounting a measurement sensor such as an oxygen probe. The housing is formed by a hole extended by an insert produced directly through the conduit element.

Abstract: The present invention provides a catalyst structure of high catalytic activity and a fuel cell of high cell output. The catalyst structure comprises a conductive film and catalyst particles formed on the conductive film wherein the difference between lattice constant of a material constituting the conductive film and that of a material constituting the catalyst particles is not more than 16%, and preferably not less than 3%.

Abstract: A secondary air supplying apparatus of the present invention comprises a secondary air supplying device for supplying secondary air to upstream of an emission purifying device in an exhaust system of an internal combustion engine, a coolant temperature sensor for detecting a temperature of a coolant for the engine, an intake air temperature sensor for detecting a temperature of intake air, a supply controller for actuating the secondary air supplying device in accordance with a predetermined secondary air supply condition, and a summing unit for summing an actuation period of the secondary air supplying device and storing a sum. The supply controller stops the secondary air supply by the secondary air supplying device when the sum stored by the summing unit reaches a predetermined upper limit.

Abstract: There is provided a control system for an internal combustion engine, which is capable of meeting a driver's demand of torque, and achieving high combustion efficiency and high emission-reducing performance by a three-way catalyst in lean-burn operation in a compatible manner. The control system sets a control amount indicative of either an oxygen mass supplied to a combustion chamber or a fuel injection amount such that oxygen concentration in exhaust gases becomes equal to a value corresponding to stoichiometric combustion. A target value corresponding to a demanded torque is set based on detected engine operating conditions. A degree of opening of a main throttle valve and a degree of opening of a sub-throttle valve in a passage by passing an intake passage equipped with a nitrogen-enriching device are controlled such that the control amount becomes equal to the set target value.

Abstract: An engine control system provides a gas concentration detection output irrespective of variation in product or change due to passage of time using an on-vehicle exhaust gas sensor. An exhaust gas sensor 107 and an electric heater 119 are connected to a microprocessor 120a, and an oxygen-concentration detection output Ip of exhaust gas, a calibration signal Vc and an internal resistance detection signal Vr are inputted through A/D converter 125. A program memory 121a stores standard characteristic data of the exhaust gas sensor 107. An atmospheric air oxygen-concentration detection output Ip0 under fuel-cut drive is measured and monitored. The electric heater 119 controls temperature so that the output coincides with the stored value. Current internal resistance of the exhaust gas sensor 107 is read and stored as target resistance. In normal driving, the electric heater 119 is controlled so that the internal resistance becomes the target resistance.