Abstract: A failure determination device capable of performing failure determination for a shutter device of a vehicle with accuracy in a short time period. In an engine room of a vehicle, a condenser for a refrigeration cycle for an aircon is provided and at a front grille of the vehicle, a grille shutter device is provided for introducing ambient air for cooling the condenser into the engine room by opening a grille shutter. According to the failure determination device of the shutter device, a pressure of the refrigerant discharged from the condenser is detected as a refrigerant pressure. A failure of the grille shutter device is determined based on the refrigerant pressure, which changes at a large rate according to the opening/closing of the grille shutter, enabling failure determination with accuracy in a short time period.

Abstract: The invention provides a deterioration diagnostic device for diagnosing a degradation condition of an exhaust gas purifier disposed in an exhaust passage in an engine based on a sensor value of an exhaust gas sensor that is disposed downstream of the purifier. The device includes detecting-signal generating unit for generating a detecting-signal having particular frequency components and multiplying the generated signal to a basic fuel injection amount so as to calculate a fuel injection amount and exhaust gas purifier evaluating for extracting a frequency response corresponding to the detecting-signal from an output of the exhaust gas sensor of the engine, the output being in response to the calculated fuel injection amount, so as to determine a condition of the purifier based on the extracted frequency response.

Abstract: A failure determination device capable of performing failure determination for a shutter device of a vehicle with accuracy in a short time period. In an engine room of a vehicle, a condenser for a refrigeration cycle for an aircon is provided and at a front grille of the vehicle, a grille shutter device is provided for introducing ambient air for cooling the condenser into the engine room by opening a grille shutter. According to the failure determination device of the shutter device, a pressure of the refrigerant discharged from the condenser is detected as a refrigerant pressure. A failure of the grille shutter device is determined based on the refrigerant pressure, which changes at a large rate according to the opening/closing of the grille shutter, enabling failure determination with accuracy in a short time period.

Abstract: An exhaust gas purifying apparatus for an internal combustion engine having a particulate filter provided in an exhaust system of the engine. Regeneration control is performed of burning particulates accumulated in the particulate filter. An oxygen concentration in exhaust gases flowing into the particulate filter is detected, and a flow rate of oxygen flowing into the particulate filter is calculated according to the detected oxygen concentration. An inflowing oxygen amount is calculated by integrating the oxygen flow rate when performing regeneration control. It is determined that an abnormality has occurred if the inflowing oxygen amount at a time when regeneration control ends is equal to or less than a predetermined amount.

Abstract: An exhaust gas purifying apparatus for an internal combustion engine, including a particulate filter provided in an exhaust passage of the engine; a pressure difference sensor for detecting a pressure difference between upstream and downstream side pressures of the particulate filter; an upstream side passage, which connects the pressure difference sensor and an upstream side with respect to the particulate filter of the exhaust passage; and a downstream side passage, which connects the pressure difference sensor and a downstream side with respect to the particulate filter of the exhaust passage. An exhaust gas flow rate is calculated according to an operating condition of the engine. A characteristic of change in the pressure difference, which is detected by the pressure difference detector and corresponds to a change in the exhaust gas flow rate, is detected. An abnormality of the downstream side passage is determined based on the characteristic of change in the pressure difference.

Abstract: An exhaust gas purifying apparatus for an internal combustion engine is provided with a NOx removing device and a particulate filter in an exhaust system. A temperature of the exhaust system is detected. A switching control is performed for alternately performing a process for removing sulfur oxide accumulated in said NOx removing device and a regeneration process for burning particulates trapped in said particulate filter, when it is determined to be necessary to perform at least one of the removal of the sulfur oxide in said NOx removing device and the regeneration of the particulate filter. The switching control is performed according to the detected exhaust system temperature.

Abstract: Air-fuel ratio control system for an engine having a catalyst purifying exhaust gases, first oxygen sensor disposed upstream of the catalyst, and second oxygen sensor disposed downstream. Intake air flow rate is detected. An amount of oxygen flowing into the catalyst is calculated using oxygen concentration detected by the first sensor and the detected intake air flow rate. The air-fuel ratio is alternately controlled to lean and rich by comparison between the calculated oxygen amount and target values. A rich oxygen amount and a lean oxygen amount are calculated. A correction amount for correcting the first sensor output is calculated based on the rich oxygen amount, the lean oxygen amount, and an accumulated value of the detected intake air flow rate. The oxygen concentration corrected with the correction amount is used for calculating the inflowing oxygen amount, the rich operation oxygen amount, and the lean operation oxygen amount.

Abstract: A deterioration detecting apparatus for a purifying catalyst in an exhaust system of an engine. A first oxygen concentration sensor is disposed upstream of the catalyst. A second oxygen concentration sensor is disposed downstream. An amount of oxygen flowing into the catalyst is calculated from the oxygen concentration detected by the first sensor and the detected intake air flow rate. A control command value of an air-fuel ratio is alternately switched between a first value corresponding to a lean air-fuel ratio and a second value corresponding to a rich air-fuel ratio according to a result of comparison between the calculated inflowing oxygen amount and target values. Excessive inflowing oxygen amounts are calculated. The target values are corrected with the excessive inflowing oxygen amount. A deterioration degree of the catalyst is detected based on an output of the second sensor when performing the switching of the control command value using the corrected target values.

Abstract: A deterioration determination device for an exhaust emission reduction device which is capable of accurately and rapidly determining deterioration of a NOx purifying catalyst. The deterioration determination device for the exhaust emission reduction device for determining deterioration of the NOx purifying catalyst includes an ECU. The ECU executes high NOx concentration control in deterioration determination, calculates a NOx supply amount based on upstream NOx concentration detected during execution of the high NOx concentration control, calculates a NOx slip amount based on downstream NOx concentration detected during execution of the high NOx concentration control, and determines the NOx purifying catalyst to be deteriorated when the condition of the NOx slip amount >a reference value is satisfied, in a case where the NOx supply amount> a reference value holds.

Abstract: An exhaust gas purifying apparatus for an internal combustion engine having a particulate filter provided in an exhaust system of the engine. Regeneration control is performed of burning particulates accumulated in the particulate filter. An oxygen concentration in exhaust gases flowing into the particulate filter is detected, and a flow rate of oxygen flowing into the particulate filter is calculated according to the detected oxygen concentration. An inflowing oxygen amount is calculated by integrating the oxygen flow rate when performing regeneration control. It is determined that an abnormality has occurred if the inflowing oxygen amount at a time when regeneration control ends is equal to or less than a predetermined amount.

Abstract: An exhaust gas purifying apparatus for an internal combustion engine, including a particulate filter provided in an exhaust passage of the engine; a pressure difference sensor for detecting a pressure difference between upstream and downstream side pressures of the particulate filter; an upstream side passage, which connects the pressure difference sensor and an upstream side with respect to the particulate filter of the exhaust passage; and a downstream side passage, which connects the pressure difference sensor and a downstream side with respect to the particulate filter of the exhaust passage. An exhaust gas flow rate is calculated according to an operating condition of the engine. A characteristic of change in the pressure difference, which is detected by the pressure difference detector and corresponds to a change in the exhaust gas flow rate, is detected. An abnormality of the downstream side passage is determined based on the characteristic of change in the pressure difference.

Abstract: An exhaust gas purifying apparatus for an internal combustion engine is provided with a NOx removing device and a particulate filter in an exhaust system. A temperature of the exhaust system is detected. A switching control is performed for alternately performing a process for removing sulfur oxide accumulated in said NOx removing device and a regeneration process for burning particulates trapped in said particulate filter, when it is determined to be necessary to perform at least one of the removal of the sulfur oxide in said NOx removing device and the regeneration of the particulate filter. The switching control is performed according to the detected exhaust system temperature.

Abstract: An air-fuel ratio control system for an internal combustion engine having a catalyst provided in an exhaust system of the engine for purifying exhaust gases and a first oxygen concentration sensor disposed upstream of the catalyst is disclosed. The air-fuel ratio control system controls an air-fuel ratio of an air-fuel mixture supplied to the engine. A degree of response deterioration of the first oxygen concentration sensor is detected. A response delay of the first oxygen concentration sensor is compensated according to the detected degree of deterioration to calculate a compensated sensor output. The air-fuel ratio is controlled so that a detected air-fuel ratio calculated from the compensated sensor output coincides with a target air-fuel ratio. A frequency characteristic of the compensation is adjusted according to the detected degree of deterioration.

Abstract: Air-fuel ratio control system for an engine having a catalyst purifying exhaust gases, first oxygen sensor disposed upstream of the catalyst, and second oxygen sensor disposed downstream. Intake air flow rate is detected. An amount of oxygen flowing into the catalyst is calculated using oxygen concentration detected by the first sensor and the detected intake air flow rate. The air-fuel ratio is alternately controlled to lean and rich by comparison between the calculated oxygen amount and target values. A rich oxygen amount and a lean oxygen amount are calculated. A correction amount for correcting the first sensor output is calculated based on the rich oxygen amount, the lean oxygen amount, and an accumulated value of the detected intake air flow rate. The oxygen concentration corrected with the correction amount is used for calculating the inflowing oxygen amount, the rich operation oxygen amount, and the lean operation oxygen amount.

Abstract: An air-fuel ratio control system for an internal combustion engine having a catalyst provided in an exhaust system of the engine for purifying exhaust gases and a first oxygen concentration sensor disposed upstream of the catalyst is disclosed. The air-fuel ratio control system controls an air-fuel ratio of an air-fuel mixture supplied to the engine. A degree of response deterioration of the first oxygen concentration sensor is detected. A response delay of the first oxygen concentration sensor is compensated according to the detected degree of deterioration to calculate a compensated sensor output. The air-fuel ratio is controlled so that a detected air-fuel ratio calculated from the compensated sensor output coincides with a target air-fuel ratio. A frequency characteristic of the compensation is adjusted according to the detected degree of deterioration.

Abstract: A deterioration detecting apparatus for a purifying catalyst in an exhaust system of an engine. A first oxygen concentration sensor is disposed upstream of the catalyst. A second oxygen concentration sensor is disposed downstream. An amount of oxygen flowing into the catalyst is calculated from the oxygen concentration detected by the first sensor and the detected intake air flow rate. A control command value of an air-fuel ratio is alternately switched between a first value corresponding to a lean air-fuel ratio and a second value corresponding to a rich air-fuel ratio according to a result of comparison between the calculated inflowing oxygen amount and target values. Excessive inflowing oxygen amounts are calculated. The target values are corrected with the excessive inflowing oxygen amount. A deterioration degree of the catalyst is detected based on an output of the second sensor when performing the switching of the control command value using the corrected target values.

Abstract: A control system for an internal combustion engine is disclosed. The engine has an exhaust gas recirculation device which includes an exhaust gas recirculation passage for recirculating exhaust gases from the engine to an intake system of the engine, and an exhaust gas recirculation control valve provided in the exhaust gas recirculation passage, for controlling a flow rate of the exhaust gases. An air-fuel ratio control amount is calculated based on an output of the air-fuel ratio sensor provided in the exhaust system of the engine. The air-fuel ratio of the air-fuel mixture supplied to the engine is controlled with the air-fuel ratio control amount. A failure of the exhaust gas recirculation device is determined based on a changing component of the air-fuel ratio control amount when changing an opening of the exhaust gas recirculation control valve in a predetermined cycle.

Abstract: A control system for an internal combustion engine is disclosed. The engine has an exhaust gas recirculation device which includes an exhaust gas recirculation passage for recirculating exhaust gases from the engine to an intake system of the engine, and an exhaust gas recirculation control valve provided in the exhaust gas recirculation passage, for controlling a flow rate of the exhaust gases. An air-fuel ratio control amount is calculated based on an output of the air-fuel ratio sensor provided in the exhaust system of the engine. The air-fuel ratio of the air-fuel mixture supplied to the engine is controlled with the air-fuel ratio control amount. A failure of the exhaust gas recirculation device is determined based on a changing component of the air-fuel ratio control amount when changing an opening of the exhaust gas recirculation control valve in a predetermined cycle.

Abstract: A deterioration failure diagnostic apparatus is provided for diagnosing an exhaust gas sensor disposed in an exhaust passage of an engine. The apparatus has a unit for generating a detecting signal and multiplying the generated signal to a first basic fuel injection amount to produce a second fuel injection amount. The apparatus includes a unit for calculating a feedback representative value based on feedback correction coefficients and multiplying the feedback representative value to the second fuel injection amount to produce a final fuel injection amount to be input to the engine. The apparatus includes a unit for extracting a frequency response corresponding to the detecting signal from an output of the exhaust gas sensor of the engine, the output being responsive to the calculated final fuel injection amount. A condition of the exhaust gas sensor is determined based on the extracted frequency response.

Abstract: An air-fuel ratio control system for an internal combustion engine, which is capable of quickly and properly eliminating variation in air-fuel ratio between a plurality of cylinders. The air-fuel ratio control system 1 controls the amount of fuel to be supplied to first to fourth cylinders #1 to #4, on a cylinder-by-cylinder basis, thereby controlling the air-fuel ratio of a mixture supplied to each of the cylinders. A LAF sensor 14 delivers to an ECU 2 an output KACT indicative of the air-fuel ratio of exhaust gases emitted from the cylinders and merged. A cycle filter 23a and a rotation filter 23b filters the output KACT from the LAF sensor 14 such that components in respective bands of a first frequency fr1 and a second frequency fr2 are allowed to pass therethrough.