Method and apparatus for determining the ethanol proportion of the fuel in a motor vehicle

US8387445B2 · kind B2 · utility

Assignee

• CONTINENTAL AUTOMOTIVE GMBH · DE

Inventors

• Gerhard Haft · Munich, DE
• Rainer List · Renningen, DE

Key dates

• Filing date: Sep 4, 2009
• Grant date: Mar 5, 2013
• Expiry date: Nov 25, 2029

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02T10/30
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Internal combustion engines which are operated using ethanol exhibit an improved capability for lean-burn running. The lean-burn running limit with a higher ethanol proportion is displaced in the direction of lean. This link between the lean-burn running limit and the ethanol proportion of the fuel is used to determine the ethanol proportion. To determine the lean-burn running limit, a fuel quantity is injected into a cylinder in the operating range of the overrun fuel cut-off, with which fuel quantity no combustion of the air/fuel mixture occurs, and the fuel quantity is increased continuously until combustion occurs; the smooth running of the engine is monitored for this cylinder and the lean-burn running limit is detected as reached if the smooth running exceeds a predefined threshold value. The ethanol proportion is then deduced from the increase in the injected fuel quantity which is required to reach the lean-burn running limit.