Two-stroke engine having an air scavenged transfer channel

US6267088A · kind A · utility

Assignee

• Andreas Stihl AG & Co. KG · DE

Inventors

• Heiko Rosskamp · Adelberg, DE
• Axel Klimmek · Schwaikheim, DE
• Lars Bergmann · Waiblingen, DE

Key dates

• Filing date: Aug 24, 2000
• Grant date: Jul 31, 2001
• Expiry date: Aug 24, 2020

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 which operates as a drive motor in a portable work apparatus such as a motor-driven chain saw. The two-stroke engine has a combustion chamber (3) which is formed in a cylinder (2) and is delimited by a piston (5) which moves up and down in the cylinder. The piston drives via a connecting rod (6) a crankshaft (7) which rotates in a crankcase (4). The crankcase (4) is connected to the combustion chamber (3) via a transfer channel (14). A first end (20) of the transfer channel (14) opens via an entry window (12) into the combustion chamber (3) and the second end (19) of the transfer channel (14) opens into the crankcase (4). The entry window (12) lies in the cylinder wall (16) and is controlled by the piston (5). The transfer channel (14) is connected to a gas channel (22) between its ends (19, 20). An essentially fuel-free gas flow (40) flows via a check valve (21) from the gas channel (22) and flows into the transfer channel (14). The mixture, which is necessary for operating the two-stroke engine (1), is drawn from a membrane carburetor (8) into the crankcase (4) via an inlet (11). The flow element (23, 33, 45) is mounted in the flow pat…