Title:
EXHAUST EMISSION CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE
Document Type and Number:
Japanese Patent JP2018173074
Kind Code:
A
Abstract:
PROBLEM TO BE SOLVED: To inhibit a wrong determination when making an abnormality diagnosis of an exhaust emission control catalyst on the basis of output from an NOx sensor.SOLUTION: An exhaust emission control device includes: an exhaust emission control catalyst 20; an NOx sensor 46 and an air-fuel ratio sensor 41 disposed downstream of the exhaust emission control catalyst 20; and a control/diagnostic system. The control/diagnostic system alternately sets a target air-fuel ratio to a rich air-fuel ratio and a lean air-fuel ratio, and switches the target air-fuel ratio from the rich air-fuel ratio to the lean air-fuel ratio when an output air-fuel ratio from the air-fuel ratio sensor reaches a rich determination air-fuel ratio or lower. The control/diagnostic system makes an abnormality diagnosis of the exhaust emission control catalyst on the basis of output from the NOx sensor. The control/diagnostic system makes the abnormality diagnosis of the exhaust emission control catalyst when an air-fuel ratio of exhaust gas flowing into the exhaust emission control catalyst is the rich air-fuel ratio, but does not make the abnormality diagnosis of the exhaust emission control catalyst when the air-fuel ratio of exhaust gas flowing into the exhaust emission control catalyst is the lean air-fuel ratio.SELECTED DRAWING: Figure 7
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Inventors:
YODA KOICHI
AOKI KEIICHIRO
HAYASHITA GO
AOKI KEIICHIRO
HAYASHITA GO
Application Number:
JP2017196290A
Publication Date:
November 08, 2018
Filing Date:
October 06, 2017
Export Citation:
Assignee:
TOYOTA MOTOR CORP
International Classes:
F01N3/20; B01D53/94; F01N3/24; F02D41/04; F02D45/00
Domestic Patent References:
| JP2002138821A | 2002-05-17 | |||
| JPH09125937A | 1997-05-13 |
Attorney, Agent or Firm:
Atsushi Aoki
Shinji Mitsuhashi
Jun Tsuruta
Koichi Ito
Nobuo Sekine
Shinji Mitsuhashi
Jun Tsuruta
Koichi Ito
Nobuo Sekine