Two-stroke engine

A two-stroke engine comprising:

• a scavenging passage opening in a combustion chamber in a scavenging stroke to fill the combustion chamber with a working gas containing a combustion fuel;
• a scavenge filling chamber communicating through a communicating port with the scavenging passage and arranged to be filled with a non-working gas in a fuel weight concentration smaller than that of the working gas prior to the scavenging stroke;
• a cylinder block forming the combustion chamber;
• a piston to reciprocate in the combustion chamber;
• and
• a crank chamber into which the working gas is to be introduced through an intake port;
• wherein in the scavenging stroke the scavenging passage and the scavenge filling chamber are made open in the combustion chamber and the non-working gas in the scavenge filling chamber is forced into the combustion chamber by the working gas inside the scavenging passage through the communicating port to scavenge the combustion chamber;
• wherein the scavenging passage and the scavenge filling chamber extend in the cylinder block so as to be adjacent to each other along an axial direction of the combustion chamber;
• wherein the scavenge filling chamber has an aperture to open in the combustion chamber when the piston is located at a position near a bottom dead center;
• wherein the scavenging passage has an aperture to open in the combustion chamber when the piston is located at a position near the bottom dead center, and one end of the scavenging passage is in communication with the crank chamber;
• and
• wherein the communicating port opens in a bulkhead interposed between the scavenging passage and the scavenge filling chamber.