| 摘要 |
A crankcase scavenged internal combustion engine, mainly intended for a handheld working tool, such as a chain saw, with an engine body (2) composed of at least one crankcase body (3, 4) and a cylinder body (5), which are joined together, and the engine is equipped with so called elongated scavenging ducts (6, 7, 6', 7'), which over some part of their length, i.e. a crankcase part (6, 6'), extend in the crankcase body (3, 4) and have their inlet (8) there, and over another part of their length, i.e. a cylinder part (7, 7'), extend in the cylinder body (5). For the sake of clarity the crankcase body (3) is not shown, however an insert part (9) is, which together with the inner side of the crankcase body (3) is forming the crankcase parts (6, 6') of the scavenging ducts. In the shown example the duct (6) is separated by side walls (12, 13), an inner wall (10) as well as the inner side of the crankcase body. Generally this means that the crankcase part (6, 6') of at least one scavenging duct to a great extent is composed of an insert part (9) with at least one inner walk (10) facing the crankshaft assembly and provided with the inlet (8), so that the crankcase part (6, 6') of the scavenging duct is composed of the insert part (9) alone or in combination with the inner side of the crankcase body, and leads from the inlet (8) to an outlet (11, 11') intended to connect to the cylinder part (7, 7') of the scavenging duct.
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