Toyota Jidosha Kabushiki Kaisha

Yazaki Corporation

Hiroshi Miyamoto

Yasushi Iwazaki

Toru Kidokoro

Kenji Suzuki

Hiroshi Sawada

Keiichiro Aoki

Fumihiko Nakamura

Shuntaro Okazaki

Yuji Miyoshi

Masahiro Kubo

Koichi Kitaura

Yasuhiro Miyazawa

Norihisa Nakagawa

Takahiko Fujiwara

Koichi Kimura

Kunihiko Yamada

Yuji Yamaguchi

You Yanagida

Senji Kato

Koji Ide

Masashi Hakariya

Tatsuhiro Hashida

Yoshihisa Oda

Masahiko Masubuchi

Takuya Matsumoto

Isao Nakajima

Ryohei Nishizaki

Koji Hagiwara

Daisuke Takanohashi

Kazutomo Fujinami

Kouichi Yamamoto

Tatsuro Shimada

Isao Takiguchi

Tatsuya Tsuji

Kouichi Kitaura

Yasushi Iwasaki

An abnormality diagnosis system of an air-fuel ratio sensor acquires a blowby gas flow ratio showing a ratio of the flow of blowby gas to the flow of gas to a combustion chamber and an output current of an air-fuel ratio sensor during fuel cut control in which an internal combustion engine stops the feed of fuel to the combustion chamber and at a plurality of points of time of different flows of blowby gas passing through a blowby gas passage and flowing to the downstream side of a throttle valve in the intake passage, calculate an output current of the air-fuel ratio sensor corresponding to a blowby gas flow ratio smaller than the blowby gas flow ratios acquired at the plurality of points of time, based on the acquired blowby gas flow ratio and output current, and judge the air-fuel ratio sensor for abnormality based on the calculated output current.

Abnormality diagnosis system of air-fuel ratio sensor

A detection device includes a switch unit, the switch unit performs switching to a gain reduction state in which a gain of a loop antenna is reduced or a gain non-reduction state in which the gain of the loop antenna is not reduced in correspondence with a state of a detection target. When a wavelength of an electric wave is set as &#x3bb;, the switch unit includes switch terminals for reducing the gain of the loop antenna within a range K1 on the loop antenna from a first circuit terminal to a position that is spaced away from the first circuit terminal by &#x3bb;/8. In addition, the switch unit includes switch terminals for reducing the gain of the loop antenna within a range on the loop antenna from a second circuit terminal to a position that is spaced away from the second circuit terminal by &#x3bb;/8.

Detection device and detection system

An internal combustion engine comprises an exhaust purification catalyst and an air-fuel ratio sensor arranged at a downstream side of the exhaust purification catalyst, stops or decreases a feed of fuel as fuel cut control, and controls an air-fuel ratio of exhaust gas to a rich air-fuel ratio after the end of the fuel cut control as post reset rich control. The diagnosis system calculates a first characteristic of change of air-fuel ratio at the time when the output air-fuel ratio first passes a first air-fuel ratio region leaner than a stoichiometric air-fuel ratio and a second characteristic of change of air-fuel ratio at the time when the output air-fuel ratio first passes a second air-fuel ratio region including a stoichiometric air-fuel ratio. The diagnosis system diagnoses the abnormality of the air-fuel ratio sensor based on the first characteristic of change of air-fuel ratio and the second characteristic of change of air-fuel ratio. As a result, it is possible to suppress the effects of the change of state of the exhaust purification catalyst while accurately diagnosing the abnormality of deterioration of response of a downstream side air-fuel ratio sensor.

Diagnosis system of internal combustion engine

An object is to prevent a wrong diagnosis from being made in diagnosis of an NOx sensor provided downstream of an SCR catalyst. A diagnosis apparatus is applied to an NOx sensor provided in an exhaust system including an SCR catalyst, a reducing agent supply device, an NOx sensor, an exhaust gas purification device provided upstream of the SCR catalyst, and a controller configured to raise the temperature of the exhaust gas purification device and control supply of reducing agent so as to adjust the ammonia adsorption amount to a specific amount. The controller is further configured to perform diagnosis of the NOx sensor on the basis of the concentration of ammonia slipping out of the SCR catalyst and disallow diagnosis of the NOx sensor since the ammonia adsorption amount is adjusted to the specific amount until a specific time elapses.

Diagnosis apparatus and diagnosis method for NOx sensor

The abnormality diagnosis system of an air-fuel ratio sensor comprising an exhaust purification catalyst, an upstream side air-fuel ratio sensor provided at an upstream side of the exhaust purification catalyst, a downstream air-fuel ratio sensor provided at a downstream side of the exhaust purification catalyst, and a diagnosis device diagnosing the downstream air-fuel ratio sensor for abnormality based on outputs of these air-fuel ratio sensors. The diagnosis device judges that the downstream air-fuel ratio sensor suffers from an abnormality if the output air-fuel ratio of the upstream side air-fuel ratio sensor has become a rich air-fuel ratio richer than a stoichiometric air-fuel ratio, and the output air-fuel ratio of the downstream air-fuel ratio sensor air-fuel ratio has changed from an air-fuel ratio richer than a lean judged reference air-fuel ratio to an air-fuel ratio leaner than the lead judged reference air-fuel ratio. As a result, it is possible to accurately diagnose an abnormality of a downstream air-fuel ratio sensor when using an air-fuel ratio sensor as a downstream side sensor.

An oil dilution rate calculation system of an internal combustion engine acquires a blowby gas flow ratio showing the ratio of the flow of blowby gas to the flow of gas to the combustion chamber and an output current of the air-fuel ratio sensor during fuel cut control in which the internal combustion engine stops the feed of fuel to the combustion chamber and at a plurality of points of time of different flows of blowby gas passing through the blowby gas passage and flowing to the downstream side of the throttle valve in the intake passage, and calculate an oil dilution rate based on the acquired blowby gas flow ratio and output current.

Oil dilution rate calculation system of internal combustion engine

An abnormality diagnosis system of an air-fuel ratio sensor is provided with an exhaust purification catalyst, an upstream side air-fuel ratio sensor which is provided at an upstream side of the exhaust purification catalyst, a downstream side air-fuel ratio sensor which is provided at a downstream side of the exhaust purification catalyst, and a diagnosis device which uses the outputs of these air-fuel ratio sensors as the basis to diagnose abnormality of the downstream side air-fuel ratio sensor.

The abnormality diagnosis system comprises an air-fuel ratio control means which sets the target air-fuel ratio of exhaust gas to a first set air-fuel ratio set to a first side of a rich side or a lean side, then, when a downstream side output air-fuel ratio is at the first side, switches the target air-fuel ratio to a second set air-fuel ratio set to a second side at the opposite side from the first side. The abnormality diagnosis system calculates the time from when the target air-fuel ratio is switched to when the downstream side output air-fuel ratio starts to change toward the stoichiometric air-fuel ratio based on a differential value of the downstream side output air-fuel ratio and, when the calculated time is a predetermined time or more, judges that a dead time at the downstream side air-fuel ratio sensor is abnormal.

Abnormality diagnosis system of downstream side air-fuel ratio sensor

An internal combustion engine comprises an exhaust purification catalyst arranged in an exhaust passage of the internal combustion engine; an upstream side air-fuel ratio sensor for detecting an air-fuel ratio of exhaust gas flowing into the exhaust purification catalyst; and a downstream side air-fuel ratio sensor for detecting an air-fuel ratio of exhaust gas flowing out from the exhaust purification catalyst. An abnormality diagnosis system of air-fuel ratio sensors judges that at least one of the air-fuel ratio sensors has become abnormal when a difference or ratio between an output value of said upstream side air-fuel ratio sensor and an output value of said downstream side air-fuel ratio sensor becomes outside a predetermined range of normal difference or predetermined range of normal ratio during atmospheric gas introduction control where the exhaust gas flowing into the exhaust purification catalyst becomes atmospheric gas.

Abnormality diagnosis system of air-fuel ratio sensors

The internal combustion engine comprises an exhaust purification catalyst, a downstream side sensor, an air-fuel ratio control unit, and an oxygen storage amount calculating unit for calculating the oxygen excess/deficiency of the inflowing exhaust gas in an air-fuel ratio maintenance time period and cumulatively adding the calculated oxygen excess/deficiency to calculate a maximum oxygen storage amount of the exhaust purification catalyst. The oxygen storage amount calculating unit uses a point of time that an absolute value of an output slope of the downstream side sensor finally becomes less than a threshold value in the air-fuel ratio maintenance time period as an end point of cumulative addition of the oxygen excess/deficiency. The threshold value is made larger when a maximum value of the absolute value of the output slope in the air-fuel ratio maintenance time period is relatively large compared to when the maximum value is relatively small.

Internal combustion engine

An abnormality diagnosis system of limit current type air-fuel ratio sensors comprises a current detecting part and a sensor temperature control device. The abnormality diagnosis system uses the current detecting part to detect the output current of the air-fuel ratio sensor when the air-fuel ratio is made the rich air-fuel ratio in the state where temperature of the air-fuel ratio is made the first temperature and when the air-fuel ratio is made the rich air-fuel ratio in the state where the temperature of the air-fuel ratio is made a second temperature higher than the first temperature. It is judged that the air-fuel ratio sensor is abnormal if the output current when the temperature of the air-fuel ratio sensor is the first temperature is larger than the output current when it is the second temperature by a predetermined value or more.

The internal combustion engine comprises an exhaust purification catalyst able to store oxygen, and a downstream side air-fuel ratio sensor arranged at a downstream side of the exhaust purification catalyst in a direction of exhaust flow. The control system performs feedback control of an amount of fuel fed to a combustion chamber of the internal combustion engine so that an air-fuel ratio of exhaust gas flowing into the exhaust purification catalyst becomes a target air-fuel ratio and performs learning control to correct a parameter relating to the feedback control based on an air-fuel ratio of exhaust gas detected by the downstream side air-fuel ratio sensor. The target air-fuel ratio is alternately switched between a rich set air-fuel ratio and a lean set air-fuel ratio leaner. When a condition for learning acceleration, which is satisfied when it is necessary to accelerate correction of the parameter by the learning control, is satisfied, a rich degree of the rich set air-fuel ratio is increased. Therefore, there is provided an internal combustion engine able to suitably change the speed of updating the learning value.

Control system of internal combustion engine

An exhaust purification system comprises an exhaust purification catalyst, a downstream side air-fuel ratio sensor and a control device. The control device makes the air-fuel ratio of the exhaust gas change to an air-fuel ratio at a rich side from the prior air-fuel ratio as air-fuel ratio rich increasing control when the air-fuel ratio of the exhaust gas is made a rich air-fuel ratio and the output air-fuel ratio of the downstream side air-fuel ratio sensor is maintained at a lean judged air-fuel ratio or more, and judges that the downstream side air-fuel ratio sensor suffers from an abnormality, when, due to the air-fuel ratio rich increasing control, the air-fuel ratio of the exhaust gas is made to change to the rich side air-fuel ratio and the output air-fuel ratio of the downstream side air-fuel ratio sensor changes to the lean side.

Exhaust purification system of internal combustion engine

An electronic control unit (ECU) of an internal combustion engine, which includes an air-fuel ratio sensor arranged at a downstream side of an exhaust purification catalyst, is configured to judge if a state of the air-fuel ratio sensor is normal or abnormal based on the first characteristic of change of air-fuel ratio and, if a judgment cannot be made based on the first characteristic, the ECU is configured to judge if the state of the air-fuel ratio sensor is normal or abnormal based on a second characteristic of change of air-fuel ratio. As a result, it is possible to suppress the effects of the change of state of the exhaust purification catalyst while accurately diagnosing the abnormality of deterioration of response of a downstream side air-fuel ratio sensor.

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Susono, Japan

Hiroshi Miyamoto