Two-state internal combustion engine

US5284111A · kind A · utility

Assignee

• Andreas Stihl AG & Co. KG · DE

Inventors

• Werner Geyer · Newton, US
• Ralf Tuckermann · Stuttgart, DE

Key dates

• Filing date: Jun 3, 1993
• Grant date: Feb 8, 1994
• Expiry date: Jun 3, 2013

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02T10/12
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

The invention is directed to a two-stroke internal combustion engine for handheld portable tools such as a motor-driven chain saw with the engine having a piston guided in a cylinder. The base of the piston is rotationally symmetrical and delimits a combustion chamber. An injection valve is mounted in the cylinder wall opposite an exhaust opening for exhaust gases. The injection valve injects fuel toward the piston base at an angle of less than 90.degree.. At least one overflow opening is arranged in the cylinder wall between the exhaust opening and the injection valve. Combustion air flows in through the overflow opening with the downward movement of the piston. The injection jet is directed opposite to the flow direction of the entering combustion air. The injection jet is directed for the most part to the half of the piston base which is disposed away from the exhaust opening and the injection opening is the last opening to be closed by the piston travelling toward top dead center. The duration of injection is continued beyond the closure of the overflow opening and of the exhaust outlet. In this way, an optimal air/fuel mixture is assured even at high rotational speeds.