Abstract: An upstream-side catalyst is arranged in an exhaust passage and a downstream-side catalyst is arranged in the exhaust passage downstream of the upstream-side catalyst. An air-fuel ratio sensor is attached for detecting the air-fuel ratio in the exhaust passage between the upstream-side catalyst and downstream-side catalyst. A representative upstream-side stored oxygen value OXU is calculated based on whether the control state of the engine is the “slight rich” control, “slight lean” control, fuel increase correction, or engine fuel cut and a representative downstream-side stored oxygen value OXD is calculated based on the engine control state and the output of the air-fuel ratio sensor.

Abstract: The present invention judges whether an internal combustion engine is operated by a special operation method in which a fuel cut is performed more frequently than predefined depending on the operation of an accelerator pedal. The present invention provides a shorter purge resumption period subsequently to recovery from a fuel cut when it is judged that the internal combustion engine is operated by the special operation method than when it is judged that the internal combustion engine is not operated by the special operation method. The purge resumption period is a period during which a purge gas flow rate is lower than during a steady operation.

Abstract: From the start of the engine to the detection of an engine speed peak, a control parameter (e.g., ignition timing) different from an air intake rate relating to an engine output is set to a value at which the engine output decreases than at an idling value. After detection of the peak, the control parameter is adjusted to the idling value.

Abstract: An intake-negative-pressure-increasing apparatus is disclosed, for use with an engine, and comprises a bypass passage extending from an intake pipe portion in the neighborhood of the throttle valve to an intake pipe portion downstream of the intake pipe portion in the neighborhood of the throttle valve. A negative pressure is generated by the air flowing through the bypass passage and is supplied to an actuator operated by the negative pressure as the driving power.

Abstract: The present invention judges whether an internal combustion engine is operated by a special operation method in which a fuel cut is performed more frequently than predefined depending on the operation of an accelerator pedal. The present invention provides a shorter purge resumption period subsequently to recovery from a fuel cut when it is judged that the internal combustion engine is operated by the special operation method than when it is judged that the internal combustion engine is not operated by the special operation method. The purge resumption period is a period during which a purge gas flow rate is lower than during a steady operation.

Abstract: A control device of an internal combustion engine suppressing catalyst deterioration by prohibiting fuel cuts, wherein the generation of odor from the catalyst after deceleration is suppressed. The control device is provided with a fuel cut executing device for stopping the supply of fuel to an internal combustion engine when a vehicle is in a decelerating state and a fuel cut prohibiting device for prohibiting a fuel cut when a temperature of a catalyst provided in an exhaust system is a predetermined temperature or more, wherein when a fuel cut is prohibited by the fuel cut prohibiting device when the vehicle decelerates in a predetermined period after an increased fuel operation is performed, the internal combustion engine is operated so that the combustion air-fuel ratio becomes lean in the decelerating state or in the decelerating state and its succeeding idling state.

Abstract: When the determination result of failure determination at a start of AI (auxiliary air injection=supply) is that there is a possibility of a closing anomaly due to freezing, a reevaluation process 1 being a reevaluation after a warm-up is performed. When the determination result of determination at an end of AI is that there is a possibility of an opening anomaly due to freezing, a reevaluation process 2 being a reevaluation after a warm-up is performed.

Abstract: The invention relates to a secondary air feeding apparatus and a method of detecting an abnormality in the apparatus capable of making a precise determination on abnormalities in components and detecting operational failures as well. According to one aspect of the invention, the opening-closing state of opening-closing means (ASV) is switched during the operation of an air pump, and abnormalities in respective components are detected on the basis of pressure values and pressure fluctuation values detected by a pressure sensor disposed between the air pump and the ASV before and after the switching of the opening-closing means.

Abstract: From the start of the engine to the detection of an engine speed peak, a control parameter (e.g., ignition timing) different from an air intake rate relating to an engine output is set to a value at which the engine output decreases than at an idling value. After detection of the peak, the control parameter is adjusted to the idling value.

Abstract: An air-fuel ratio control apparatus of an internal combustion engine includes: an exhaust gas purifying catalyst disposed in an exhaust passage of the internal combustion engine; fuel cutting means for cutting fuel to be supplied to the internal combustion engine at the time of deceleration of the internal combustion engine; and catalyst degradation suppressing means for suppressing degradation of the exhaust gas purifying catalyst by prohibiting operation of the fuel cutting means when it is determined that the degradation of the exhaust gas purifying catalyst advances, wherein the catalyst degradation suppressing means sets an operation permitting period, during which the operation of the fuel cutting means is permitted after completion of a fuel quantity increasing operation of the internal combustion engine.

Abstract: An air-fuel ratio control apparatus of an internal combustion engine in which an exhaust gas purifying catalyst is disposed in an exhaust passage, comprises: fuel cut means which stops fuel supply to the internal combustion engine when it is determined that a number of revolutions of the internal combustion engine is higher than a fuel cut number of revolutions at the time of deceleration of the internal combustion engine; and changing means of the fuel cut number of revolutions for changing the fuel cut number of revolutions according to a physical amount which correlates with an amount of oxygen discharged from the exhaust gas purifying catalyst during the fuel increasing operation of the internal combustion engine such that as the amount of oxygen is greater, the fuel cut number of revolutions is reduced.

Abstract: An upstream-side catalyst is arranged in an exhaust passage and a downstream-side catalyst is arranged in the exhaust passage downstream of the upstream-side catalyst. An air-fuel ratio sensor is attached for detecting the air-fuel ratio in the exhaust passage between the upstream-side catalyst and downstream-side catalyst. A representative upstream-side stored oxygen value OXU is calculated based on whether the control state of the engine is the “slight rich” control, “slight lean” control, fuel increase correction, or engine fuel cut and a representative downstream-side stored oxygen value OXD is calculated based on the engine control state and the output of the air-fuel ratio sensor.

Abstract: Injection of secondary air (AI) into an exhaust gas pipe upstream of an exhaust gas purification catalyst is performed after a startup of an engine, in order to accelerate the warm-up of the catalyst. If the degree of catalyst warm-up during the AI is greater than or equal to a predetermined criterion degree of the warm-up and the engine output is greater than or equal to a criterion output, the injection of secondary air is stopped and exhaust gas purification on the catalyst is conducted so as to curb degradation of emissions.

Abstract: An intake air oxygen concentration sensor calibration device is provided with an oxygen concentration sensor that detects a concentration of oxygen contained in intake air, intake passageway pressure detection means, stable condition determination means that determines whether the intake passageway pressure is in a stable condition based on the amplitude of fluctuations in intake passageway pressure and a predetermined stable condition criterion value, calibration coefficient calculation means that calculates a calibration coefficient based on the intake passageway pressure and a reference output value of the oxygen concentration sensor, and calibration means that calibrates the output of the oxygen concentration sensor based on the calibration coefficient, wherein and the stable condition criterion value is set so that the smaller the intake passageway pressure detected, the smaller the value, and the greater the intake passageway pressure detected, the greater the value, and the calibration coefficient calc

Abstract: Correction of a fuel injection amount in an internal combustion engine during purge of evaporative fuel is performed on the basis of an output from an intake-oxygen concentration sensor disposed in an intake passage of the internal combustion engine. If the amplitude of fluctuations in engine speed becomes equal to or greater than a predetermined value, it is determined that there is an anomaly in engine output. In addition, if an anomaly in engine output is detected during purge and if no anomaly in engine output is detected during stoppage of purge, an ECU determines that an anomaly has occurred in the intake-oxygen concentration sensor, cancels correction of the fuel injection amount based on an output from the intake-oxygen concentration sensor during purge, and corrects the fuel injection amount on the basis of outputs from exhaust-gas air-fuel ratio sensors.

Abstract: An intake air oxygen concentration sensor calibration device is provided with an oxygen concentration sensor that detects a concentration of oxygen contained in intake air, intake passageway pressure detection means, stable condition determination means that determines whether the intake passageway pressure is in a stable condition based on the amplitude of fluctuations in intake passageway pressure and a predetermined stable condition criterion value, calibration coefficient calculation means that calculates a calibration coefficient based on the intake passageway pressure and a reference output value of the oxygen concentration sensor, and calibration means that calibrates the output of the oxygen concentration sensor based on the calibration coefficient, wherein and the stable condition criterion value is set so that the smaller the intake passageway pressure detected, the smaller the value, and the greater the intake passageway pressure detected, the greater the value, and the calibration coefficient calc

Abstract: A fuel vapor handling apparatus supplies a purging air to a canister by using a purge pump and purges fuel desorbed from the canister into an intake pipe. A controller intermittently operates the purge so that the canister internal temperature recovers from a reduced level caused by the latent heat of vaporization of fuel during an operating period of the purge pump. Therefore, desorption of fuel from the canister during an operating period is facilitated. Since the actual operating time of the purge pump is reduced, the life of a motor that is a power unit of the purge pump becomes longer.

Abstract: Injection of secondary air (AI) into an exhaust gas pipe upstream of an exhaust gas purification catalyst is performed after a startup of an engine, in order to accelerate the warm-up of the catalyst. If the degree of catalyst warm-up during the AI is greater than or equal to a predetermined criterion degree of the warm-up and the engine output is greater than or equal to a criterion output, the injection of secondary air is stopped and exhaust gas purification on the catalyst is conducted so as to curb degradation of emissions.

Abstract: The invention relates to a secondary air feeding apparatus and a method of detecting an abnormality in the apparatus capable of making a precise determination on abnormalities in components and detecting operational failures as well. According to one aspect of the invention, the opening-closing state of opening-closing means (ASV) is switched during the operation of an air pump, and abnormalities in respective components are detected on the basis of pressure values and pressure fluctuation values detected by a pressure sensor disposed between the air pump and the ASV before and after the switching of the opening-closing means.

Abstract: An evaporative fuel leakage preventing device is designed such that an adsorbent is disposed in an intake passage so as to adsorb evaporative fuel generated in the intake passage during stoppage of the engine and prevent evaporative fuel from being discharged to the atmosphere. The device prevents evaporative fuel that has been previously adsorbed by the adsorbent, and that is desorbed from the adsorbent due to the ambient temperature while the engine is not in operation, from being emitted to the atmosphere even when the engine is not in operation.