| 摘要 |
PURPOSE:To enable an interlocking mechanism to be protected even if an engine is exposed to earth and sand and muddy water, by housing the interlocking mechanism, connected between a driving gear and an opening and closing valve, to be sealed in a mechanism chamber integrally formed with the main unit of the engine. CONSTITUTION:An interlocking mechanism M is housed in a mechanism chamber 50 integrally formed in a series of walls in a crank case and a cylinder block. The mechanism chamber 50, whose upper part neighbors to an outlet hole 15c of a branch path 15 interposing a partition, has an opening part 52 in an outside face of the cylinder block 2. The opening part 52 is closed by a cover plate 21a. The cover plate 21a is formed from the extension part of a gasket 21 between the cylinder block and a resonance chamber 16, and the chamber 16, for retaining the cover plate 21a, is formed to be swollen to a side of the opening part 52 of the mechanism chamber 50. An opening and closing valve 24 is opened when an engine E is driven in its low and intermediate speed range while closed when the engine E is driven in its high speed range. |
