
US Patent No: 6,138,453
Number of patents in Portfolio can not be more than 2000
Exhaust gas purification device for an internal combustion engine
Stats
-
Oct 31, 2000
Issued date -
Sep 10, 1998
filing date -
09/151,230
serial no -
In Force
status
Importance
Abstract
In an exhaust gas purification device for an internal combustion engine, a NO.sub.X occluding and reducing catalyst is disposed in the exhaust gas passage of an engine. The NO.sub.X occluding and reducing catalyst absorbs NO.sub.X in the exhaust gas when the air-fuel ratio of the exhaust gas is at a lean air-fuel ratio and releases and reduces NO.sub.X when the air-fuel ratio of the exhaust gas is at a rich air-fuel ratio. The air-fuel ratio of the exhaust gas flowing out from the catalyst is detected by an air-fuel ratio sensor disposed in the exhaust gas passage downstream of the catalyst. When the air-fuel ratio of the exhaust gas flowing into the catalyst is changed from a rich air-fuel ratio to a lean air-fuel ratio, the air-fuel ratio of the exhaust gas flowing out from the catalyst stays at a stoichiometric air-fuel ratio before it changes to a lean air-fuel ratio. The length of the period in which the air-fuel ratio of the exhaust gas flowing out from the catalyst stays at a stoichiometric air-fuel ratio corresponds to the magnitude of the ability of the NO.sub.X occluding and reducing catalyst as a reducing catalyst. Thus, by measuring the length of the stoichiometric air-fuel ratio period of the exhaust gas flowing out from the NO.sub.X occluding and reducing catalyst, the ability of the NO.sub.X occluding and reducing catalyst as a reducing catalyst can be precisely evaluated.
First Claim
Related Publications
International Classification(s)
- [Classification Symbol]
- [Patents Count]
Cited Art
| Patent Info | (Count) | # Cites | Year |
|---|---|---|---|
|
|
|||
| 5,448,887 Exhaust gas purification device for an engine | 80 | 1994 | |
| 5,732,553 Device for determining deterioration of a catalytic converter for an engine | 13 | 1996 | |
| 5,778,667 Method and a device for purifying combustion exhaust gas | 31 | 1997 | |
| 5,983,629 Device for determining deterioration of a catalyst for an engine | 15 | 1997 | |
| 5,970,707 Exhaust gas purification device for an internal combustion engine | 93 | 1998 | |
|
|
|||
| 8,014,031 Formation of picture image having gradation expressed by fill area and one-line image data | 2 | 2008 | |
|
|
|||
| 5,325,664 System for determining deterioration of catalysts of internal combustion engines | 100 | 1992 | |