Two-stroke engine

US6523509B2 · kind B2 · utility

Assignee

• Andreas Stihl AG & Co. KG · DE

Inventors

• Jochen Kramer
• Lars Bergmann · Waiblingen, DE
• Michael Raffenberg · Fellbach, DE
• Heiko Rosskamp · Adelberg, DE

Key dates

• Filing date: Sep 5, 2001
• Grant date: Feb 25, 2003
• Expiry date: Sep 5, 2021

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F02B2075/025
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

The invention relates to a two-stroke engine for a portable handheld work apparatus such as a motor-driven chain saw, cutoff machine, brushcutter or the like. A crankcase (4) is formed below the engine cylinder (2). A piston (5) moves up and down in the cylinder (2) and drives a crankshaft (7) rotatably journalled in the crankcase (4). A fuel-containing mixture is supplied via a membrane carburetor (8) to the combustion chamber (3) delimited between the piston (5) and the cylinder (2). A bypass channel (22) is provided parallel thereto and supplies essentially fuel-free air to the combustion chamber (3). The bypass channel (22) opens into a channel segment (21) via a connecting piece (24) fixedly attached to the cylinder (2). The channel segment (21) is formed in the cylinder wall (16). A spark plug (20) and an ignition control device (34) are assigned to the combustion chamber (3). The ignition control device (34) is fixedly mounted with a portion to the cylinder (2) via one attachment point (40) and is fixedly mounted to the connecting piece (24) via another attachment point (41).