Exhaust valve assembly for a two-stroke internal combustion engine

US11891930B2 · kind B2 · utility

Assignee

• BRP-ROTAX GMBH & CO. KG · AT

Inventors

• Nigel Foxhall · Semriach, AT
• Markus Doppelbauer · Wels, AT
• Heinz Kusel · Schwanenstadt, AT
• Matthias Zarhuber · Bergerndorf, AT
• Roland Kirchberger · Graz, AT
• Franz Winkler · Graz, AT
• Andrea Abis · Graz, AT

Key dates

• Filing date: Dec 16, 2021
• Grant date: Feb 6, 2024
• Expiry date: Dec 16, 2041

Classification

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

Abstract

A method of operating an exhaust valve of a two-stroke internal combustion engine is disclosed. The engine has a cylinder and a piston movably disposed within the cylinder. The cylinder defines at least one exhaust port for discharging exhaust fluid from the cylinder. The exhaust valve is configured to cyclically obstruct the exhaust port. The method includes: rotating the exhaust valve in a first direction for clearing the exhaust port before the piston uncovers the exhaust port during a downstroke of the piston, the first direction being opposite a direction of rotation of a crankshaft of the engine; and rotating the exhaust valve in the first direction for at least partially closing the exhaust port before the piston fully covers the exhaust port during an upstroke of the piston, said rotating of the exhaust valve relative to the rotation of the crankshaft at least partially counterbalancing the crankshaft.