Method and a device for purifying exhaust gas of an internal combustion engine
US5979157A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 14, 1997 |
| Grant date | Nov 9, 1999 |
| Priority date | — |
| Expiry date | Aug 14, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/40
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
A device for purifying exhaust gas includes an HC adsorbent and an exhaust gas purifying catalyst disposed in an exhaust gas passage in this order from the upstream side. The exhaust gas purifying catalyst is provided with an O.sub.2 storage capability, i.e., the exhaust gas purifying catalyst is capable of absorbing oxygen in the exhaust gas when the air-fuel ratio of the exhaust gas is lean, and is capable of releasing the absorbed oxygen when the air-fuel ratio of the exhaust gas becomes rich. When the engine starts, the HC adsorbent adsorbs HC in the exhaust gas. When the temperature of the exhaust gas becomes high, the HC adsorbent releases the adsorbed HC. The device also includes an engine control unit which operates the engine at a lean air-fuel ratio during a predetermined period before the releasing of the HC from the HC adsorbent occurs. Therefore, oxygen is absorbed and stored in the exhaust gas purifying catalyst before the releasing of HC occurs. When the releasing of HC from the HC adsorbent occurs, the air-fuel ratio of the exhaust gas flowing into the exhaust gas purifying catalyst becomes rich due to the HC released from the HC adsorbent. This causes the exhaust g…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.