Two-stroke engine

US6932032B2 · kind B2 · utility

Assignee

• Andreas Stihl AG & Co. KG · DE

Inventors

• Andreas Lingen · Backnang, DE
• Matthias Hehnke · Schorndorf, DE
• Joachim Baumhauer · Trochtelfingen, DE
• Andreas Bähner · Waiblingen, DE
• Michael Joos · Fellbach, DE
• Axel Klimmek · Schwaikheim, DE
• Hans Holderle · Freiberg, DE

Key dates

• Filing date: Nov 12, 2004
• Grant date: Aug 23, 2005
• Expiry date: Nov 12, 2024

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F02D2009/0279
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

A two-stroke engine (1) has a combustion chamber (3) disposed in a cylinder (2). The combustion chamber (3) is delimited by a reciprocating piston (5). The piston (5) drives a crankshaft (7) via a connecting rod (6) and the crankshaft (7) is rotatably journalled in a crankcase (4). The two-stroke engine (1) has an intake channel (8) for the supply of fuel into the crankcase (4), an outlet (13) for exhaust gases from the combustion chamber (3) and an air channel (10) for the supply of substantially fuel-free air. A throttle element (18) is mounted in the air channel (10). At pregiven positions of the piston (5), the crankcase (4) is connected via at least one transfer channel (14) to the combustion chamber (3). In order to prevent air from being drawn by suction into the air channel because of leakages during idle or at low rpm, a fluid connection is provided between the air channel (10) downstream of the throttle element (18) and the crankcase (4) for underpressure compensation which connection is present at least partially for a position of the piston from 90° ahead of bottom dead center to 90° after bottom dead center. A connection between the crankcase (4) and the intake channel…