Catalyst activation control system for engines
US6266957A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 24, 1999 |
| Grant date | Jul 31, 2001 |
| Priority date | — |
| Expiry date | Mar 24, 2019 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/40
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
An engine variable valve timing mechanism is controlled during engine starting to set valve opening overlap of intake and exhaust valves around 30.degree. CA. In this case, internal EGR is actively conducted, fuel burning velocity within a cylinder becomes relatively slow and unburned fuel within the cylinder is emitted to an exhaust pipe to be post-burned. The temperature of exhaust gas is maintained high and catalyst converters in the cold state may be activated quickly by actively implementing such post-burning within the exhaust pipe. Further, ignition timing is retarded, the air-fuel ratio is controlled to a slightly lean ratio and the exhaust valve is advanced. The effect of raising the temperature of exhaust gas by post-burning may be realized more reliably by combining each of these controls.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.