Spark ignition engine with negative valve-overlap
US6394051B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 1, 2000 |
| Grant date | May 28, 2002 |
| Priority date | — |
| Expiry date | Sep 1, 2020 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/12
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
An internal combustion engine valve control system for improving automotive cold-starts. A “negative” valve-overlap (NVO) time period is created during a first part of each piston's intake stroke wherein, with the intake and exhaust valves closed, a high vacuum is produced in its associated cylinder. As the intake valve starts to open at the end of the period an initial small low-lift valve gap creates a high-pressure differential across the gap increasing the velocity of the air/fuel charge being injected through the gap. The added velocity elevates turbulent mixing intensity in the cylinder enhancing atomization and vaporization of the charge, improving distribution in the combustion chamber for charge stability. This allows additional spark retard and a leaner air/fuel ratio, achieving rapid catalyst warm-up, while promoting converter efficiency and reducing exhaust-gas emissions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.