Method for operating a two-stroke engine

US7894974B2 · kind B2 · utility

Assignee

• Andreas Stihl AG & Co. KG · DE

Inventors

• Andreas Bähner · Waiblingen, DE
• Andreas Lingen · Backnang, DE
• Georg Maier · Weisendorf, DE
• Heinrich Leufen · Schwaikheim, DE
• Stanislaw Cichon · Ergolding, DE
• Leo Kieβling · Cadolzburg, DE

Key dates

• Filing date: Jul 1, 2008
• Grant date: Feb 22, 2011
• Expiry date: Jan 7, 2029

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02T10/40
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

A two-stroke engine has a cylinder with a combustion chamber delimited by a reciprocating piston, wherein the piston drives in rotation a crankshaft, and wherein a spark plug projects into the combustion chamber and ignites a fuel/air mixture. The two-stroke engine further has devices for supplying fuel and combustion air to the combustion chamber and a control unit that determines the ignition timing based on an ignition map. The ignition map indicates the ignition timing as a function of the engine speed for at least one first and one second operating states and for at least one first and one second engine speed ranges. The engine is controlled in that for an engine cycle the ignition timing is set in the second operating state at least within the first engine speed range based on the engine speed and on the number of engine cycles since the last combustion.