Abstract: An intake air control apparatus for an internal-combustion engine includes an intake air adjusting device. An operating mode determination device is configured to determine whether the internal-combustion engine is in a predetermined high rotation speed and high load operation mode in which cooling is required by increasing an amount of fuel. An intake air reduction controller is configured to, if the operating mode determination device determines that the internal-combustion engine is in the predetermined high rotation speed and high load operation mode, control the intake air adjusting device so that an intake air amount is reduced in accordance with a rotation speed of the internal-combustion engine and an ignition timing in order to restrict a fuel injection quantity to be injected from a fuel injection valve so that the fuel injection quantity does not exceed a maximum fueling rate of the fuel injection valve.

Abstract: An intake air control apparatus for an internal-combustion engine includes an intake air adjusting device. An operating mode determination device is configured to determine whether the internal-combustion engine is in a predetermined high rotation speed and high load operation mode in which cooling is required by increasing an amount of fuel. An intake air reduction controller is configured to, if the operating mode determination device determines that the internal-combustion engine is in the predetermined high rotation speed and high load operation mode, control the intake air adjusting device so that an intake air amount is reduced in accordance with a rotation speed of the internal-combustion engine and an ignition timing in order to restrict a fuel injection quantity to be injected from a fuel injection valve so that the fuel injection quantity does not exceed a maximum fueling rate of the fuel injection valve.

Abstract: A control system for an internal combustion engine in which fuel containing alcohol is used. In the control system, a maximum opening of a throttle valve of the engine is set, and a target opening of the throttle valve is set to a value which is equal to or less than the maximum opening. An opening of the throttle valve is controlled so as to coincide with the target opening. The maximum opening is according to a concentration parameter indicative of a concentration of alcohol in the fuel, a temperature parameter indicative of a temperature of the engine, and a number of ignitions performed after start of the engine.

Abstract: A throttle valve control system for an internal combustion engine which controls an opening of a throttle valve of the engine so that the opening coincides with a target opening. A regulation value of a change amount of the throttle valve opening is set according to at least a temperature parameter indicative of a temperature of the engine. The target opening is set within a range defined by the regulation value. An upper limit value and a lower limit value of the regulation value is set according to the temperature parameter, and a transition control is performed wherein the regulation value is set according to an elapsed time period after start of the engine so as to change from the lower limit value to the upper limit value.

Abstract: A throttle valve control system for an internal combustion engine which controls an opening of a throttle valve of the engine so that the opening coincides with a target opening. A regulation value of a change amount of the throttle valve opening is set according to at least a temperature parameter indicative of a temperature of the engine. The target opening is set within a range defined by the regulation value. An upper limit value and a lower limit value of the regulation value is set according to the temperature parameter, and a transition control is performed wherein the regulation value is set according to an elapsed time period after start of the engine so as to change from the lower limit value to the upper limit value.

Abstract: A control system for an internal combustion engine in which fuel containing alcohol is used. In the control system, a maximum opening of a throttle valve of the engine is set, and a target opening of the throttle valve is set to a value which is equal to or less than the maximum opening. An opening of the throttle valve is controlled so as to coincide with the target opening. The maximum opening is according to a concentration parameter indicative of a concentration of alcohol in the fuel, a temperature parameter indicative of a temperature of the engine, and a number of ignitions performed after start of the engine.

Abstract: A method for detecting an abnormality in a hybrid vehicle. The hybrid vehicle includes an engine that can run in a cylinder cut-off state where intake and exhaust valve lifts are made zero, and a motor/generator that functions as both a motor and a generator. The vehicle travels by means of the power of at least one of the engine and the motor/generator and carries out regenerative braking by the motor/generator while running the engine in a cylinder cut-off state during deceleration. When detecting an abnormality in a negative intake pressure sensor or an EGR control valve based on the negative intake pressure of the engine, the engine is prohibited from running in a cylinder cut-off state even during deceleration, thus generating a negative intake pressure and thereby enabling the abnormality detection to be carried out without any problems.

Abstract: An exhaust gas purifying apparatus for an internal-combustion engine includes an exhaust gas purifier having a nitrogen oxide purifier for purifying nitrogen oxide contained in exhaust gases and an oxygen density sensor located downstream of the exhaust gas purifier. The apparatus further includes a sulfur oxide detector for detecting the density of sulfur oxide in the exhaust gas purifier, a sulfur-poisoning recovery apparatus for recovering the exhaust gas purifier from sulfur poisoning when the sulfur oxide detector determines the sulfur oxide density is high, a lean operation limiter for limiting the lean operation of the engine to such operation region that is not influenced so much by the sulfur poisoning after the exhaust gas purifier has been recovered from the sulfur poisoning, and a deterioration determiner for determining deterioration of the exhaust gas purifier based on the output of the oxygen density sensor during the lean operation of the engine.

Abstract: A failure determination system and method for an internal combustion engine and an engine control unit are provided which are capable of properly determining a failure of a variable valve mechanism for inactivating a valve system associated with at least one of cylinders during a predetermined operation of the engine, by discriminating a misfire caused by the failure of the mechanism from a normal misfire. Fuel injection valves inject fuel for each cylinder and oxygen concentration of exhaust gases is detected. A misfire condition is detected on a cylinder-by-cylinder basis. Fuel injection to a misfiring cylinder is stopped. A failure of the mechanism is determined, when a parameter based on the oxygen concentration detection indicates a richer value of an actual air-fuel ratio of the exhaust gases than a predetermined reference value does, under a condition of the fuel injection being stopped.

Abstract: The present invention provides an air-fuel ratio feedback control apparatus for an internal-combustion engine. The apparatus includes an air-fuel ratio detector that is disposed in an exhaust system of the engine so as to detect an air-fuel ratio of exhaust gas, NOx purifier for purifying NOx contained in the exhaust gas during a lean operation and feedback controller for making a feedback control upon an air-fuel ratio of air-fuel mixture to be supplied to the engine based on an output of the air-fuel ratio detector. A diagnostic system diagnoses the NOx purifier based on an output of an O2 sensor disposed downstream of the NOx purifier when the air-fuel ratio of the air-fuel mixture to be supplied to the engine has been changed from lean to rich and gain changer for making a feedback control gain of the feedback controller smaller when the air-fuel ratio is changed from lean to rich.

Abstract: An exhaust gas purifying apparatus for an internal-combustion engine, including a three-way catalyst, nitrogen oxide purifier that is disposed downstream of the three-way catalyst, an upstream oxygen sensor that is disposed between the three-way catalyst and the nitrogen oxide purifier, and a downstream oxygen sensor that is disposed downstream of the nitrogen oxide purifier. An abnormality determination criterion is set in accordance with the exhaust gas amount of the internal-combustion engine wherein the criterion is equivalent to a time period until the output of the downstream oxygen density sensor is read since the output of the upstream oxygen density sensor is changed to rich after the air-fuel ratio of the exhaust gas was over from lean to rich. Any abnormality of the nitrogen oxide purifier is determined when the output of the downstream oxygen density sensor has been changed to rich before the time period represented by the criterion elapses.

Abstract: A control apparatus for a hybrid vehicle of the present invention determines whether a brake switch flag F_BKSW is “1” or not (step S101), and in the case where the brake is on (“yes”), obtains a deceleration regeneration computation value DECRGN by table retrieval from a #REGENBR table. In the case where the brake is off (“no”), it is determined whether a fuel supply cut delay time regeneration flag F_RGNFCD is “1” or not (step S104). In the case where regeneration is not performed in the fuel supply cut delay time (“no”), a deceleration regeneration computation value DECRGN is obtained by table retrieval from a #REGEN table (step S105). On the other hand, in the case where regeneration is performed in the fuel supply cut delay time (“yes”), a deceleration regeneration computation value DECRGN is obtained by table retrieval from a #RGNNFCD table (step S106).

Abstract: A failure determination system and method for an internal combustion engine and an engine control unit are provided which are capable of properly determining a failure of a variable valve mechanism for inactivating a valve system associated with at least one of cylinders during a predetermined operation of the engine, by discriminating a misfire caused by the failure of the mechanism from a normal misfire. Fuel injection valves inject fuel for each cylinder and oxygen concentration of exhaust gases is detected. A misfire condition is detected on a cylinder-by-cylinder basis. Fuel injection to a misfiring cylinder is stopped. A failure of the mechanism is determined, when a parameter based on the oxygen concentration detection indicates a richer value of an actual air-fuel ratio of the exhaust gases than a predetermined reference value does, under a condition of the fuel injection being stopped.

Abstract: A method for detecting an abnormality in a hybrid vehicle. The hybrid vehicle includes an engine that can run in a cylinder cut-off state where intake and exhaust valve lifts are made zero, and a motor/generator that functions as both a motor and a generator. The vehicle travels by means of the power of at least one of the engine and the motor/generator and carries out regenerative braking by the motor/generator while running the engine in a cylinder cut-off state during deceleration. When detecting an abnormality in a negative intake pressure sensor or an EGR control valve based on the negative intake pressure of the engine, the engine is prohibited from running in a cylinder cut-off state even during deceleration, thus generating a negative intake pressure and thereby enabling the abnormality detection to be carried out without any problems.

Abstract: The present invention provides an air-fuel ratio feedback control apparatus for an internal-combustion engine that can avoid an overshoot of the actual air-fuel ratio when the diagnostic device for diagnosing the NOx purifier changes the air-fuel ratio from lean to rich. The apparatus comprises air-fuel ratio detector that is disposed in an exhaust system of the engine so as to detect an air-fuel ratio of exhaust gas, NOx purifier for purifying NOx contained in the exhaust gas during a lean operation and feedback controller for making a feedback control upon an air-fuel ratio of air-fuel mixture to be supplied to the engine based on an output of the air-fuel ratio detector.

Abstract: An exhaust gas purifying apparatus for an internal-combustion engine comprises a three-way catalyst, nitrogen oxide purifier that is disposed downstream of the three-way catalyst, an upstream oxygen sensor that is disposed between the three-way catalyst and the nitrogen oxide purifier, and a downstream oxygen sensor that is disposed downstream of the nitrogen oxide purifier. Means is provided for setting an abnormality determination criterion in accordance with the exhaust gas amount of the internal-combustion engine wherein the criterion is equivalent to a time period until the output of the downstream oxygen density sensor is read since the output of the upstream oxygen density sensor is changed to rich after the air-fuel ratio of the exhaust gas was turned over from lean to rich. Means is provided for determining that the nitrogen oxide purifier is abnormal when the output of the downstream oxygen density sensor has been changed to rich before the said time period represented by the criterion elapses.

Abstract: An exhaust gas purifying apparatus for an internal-combustion engine comprises an exhaust gas purifier including nitrogen oxide purifier for purifying nitrogen oxide contained in exhaust gases and an oxygen density sensor located downstream of the exhaust gas purifier. The apparatus further comprises sulfur oxide detector for detecting density of sulfur oxide in the exhaust gas purifier, sulfur-poisoning recovery means for recovering the exhaust gas purifier from sulfur poisoning when it has been determined by the sulfur oxide detector that the sulfur oxide density is high, and a lean operation limiter for limiting the lean operation of the engine to such operation region that is not influenced so much by the sulfur poisoning after the exhaust gas purifier has been recovered from the sulfur poisoning. Deterioration determining means is also provided for determining deterioration of the exhaust gas purifier based on the output of the oxygen density sensor during the lean operation of the engine.

Abstract: A control apparatus for a hybrid vehicle of the present invention determines whether a brake switch flag F_BKSW is “1” or not (step S101), and in the case where the brake is on (“yes”), obtains a deceleration regeneration computation value DECRGN by table retrieval from a #REGENBR table. In the case where the brake is off (“no”), it is determined whether a fuel supply cut delay time regeneration flag F_RGNFCD is “1” or not (step S104). In the case where regeneration is not performed in the fuel supply cut delay time (“no”), a deceleration regeneration computation value DECRGN is obtained by table retrieval from a #REGEN table (step S105). On the other hand, in the case where regeneration is performed in the fuel supply cut delay time (“yes”), a deceleration regeneration computation value DECRGN is obtained by table retrieval from a #RGNNFCD table (step S106).

Abstract: The invention relates to an apparatus for diagnosing thermostat trouble in an engine cooling system comprising a thermostat which works to open a valve to make a cooling water flow through a radiator when the cooling water temperature for an engine becomes more than a predetermined temperature, or to close the valve to make the cooling water bypass a radiator when this temperature becomes less than the predetermined temperature. The apparatus comprises means for calculating a radiation heat amount from a radiator received by the cooling water for the engine and means for determining whether the thermostat trouble has occurred based on the radiation heat amount calculated by the means for calculating the radiation heat amount.

Abstract: A valve operation verifying system for making verification of valve operation of an EGR valve of a type having a diaphragm elastically deformable according to operating conditions of an engine to admit controlled amounts of exhaust gas that is recirculated into an intake air stream which verifies, on a basis of gas pressure in an EGR passage, whether the diaphragm remains elastically deformable as specified and whether a pressure sensor remains free from freezing, and executes the verification of valve operation of the EGR valve on a basis of a change in the gas pressure in the EGR passage when the EGR valve opens and when it closes, and when the temperature of ambient air is lower than a critical point, verifying that the diaphragm remains elastically deformable as specified and that said pressure sensor is free from freezing.