Patent ID: 8726859

Claim:
A two-stroke cycle combustion engine of an air scavenging type which comprises: one or more scavenging passages for communicating a crank chamber and a combustion chamber; an air passage for supplying air; an introducing passage for introducing the air from the air passage into an upper portion of each scavenging passage from a direction radially outwardly of a cylinder block to provide scavenging air to each scavenging passage; a covering member for covering the introducing passage from an outer side; and a scavenging block connected to the cylinder block and forming the upper portion of each scavenging passage and a part of the introducing passage, the introducing passage being formed between the scavenging block and the covering member, wherein a first scavenging passage supplies air and an air/fuel mixture from within the crank chamber to the combustion chamber in which a radially outer side portion of a passage wall, forming the first scavenging passage, is formed with an introducing hole through which the air within the introducing passage is introduced, and a second scavenging passage for supplying mainly air from the introducing passage to the combustion chamber, and in which the introducing passage is communicated with the second scavenging passage through a radially outer side of the first scavenging passage, and wherein the scavenging block is formed integrally with a passage upper wall portion extending in a radial direction, and first and second partition wall portions extending downwardly from an inner side half of the passage upper wall portion occupying a region from a radially inner end portion of the passage upper wall portion to an intermediate portion thereof; and an upper portion of the first scavenging passage is formed between the first partition wall portion and the second wall portion and an upper portion of the second scavenging passage is formed between the second partition wall portion and the cylinder block.