Internal combustion engine
AssigneeWalbro Japan, Inc.
InventorTakeshi Kobayashi
Life of this patent
Estimating the term…
Abstract
A two-stroke internal combustion engine having an air control arrangement which controls scavenging air flow during rapid engine acceleration to optimize the acceleration and maximum power output of the engine while maintaining low exhaust emissions from the engine. Desirably, the air control arrangement may comprise a valve that throttles the air passage to one half or less of its total flow area at a medium engine load or less and completely or fully opens at a medium engine load or more of the engine. Normally, the air control valve opens in unison with the throttle valve, but during rapid acceleration of the engine the air control valve opens later or more slowly than the throttle valve to control the supply of scavenging air to the combustion chamber of the engine thereby enhancing rapid acceleration of the engine.
Claims20
An internal combustion engine, comprising:
- a cylinder body defining in part a combustion chamber, a crankcase chamber, a scavenging passage communicating the crankcase chamber with the combustion chamber and an intake port communicating with the crankcase chamber;
- an air passage communicating with the scavenging passage and through which air is delivered to the engine;
- a fuel and air mixture passage communicating with the intake port and through which a fuel and air mixture is delivered to the engine;
- an insulator plate carried by the cylinder body and defining at least in part the air passage and the fuel and air mixture passage;
- a carburetor defining at least in part the air passage and the fuel and air mixture passage and having a throttle valve movable between idle and wide open positions and disposed in communication with the air passage to control the flow of air therethrough;
- an air control associated with the air passage to restrict air flow through the air passage when the throttle valve is rapidly moved towards its wide open position to rapidly accelerate the engine and to permit an essentially unrestricted flow of air through the air passage when the engine is not rapidly accelerating whereby, during rapid engine acceleration a lower flow rate of air is delivered to the engine than would be delivered to the engine without any air control so that a relatively rich fuel and air mixture is available for combustion to support the rapid engine acceleration.
Dependencies are inferred from the claim text.