Patent ID: 8540051

Claim:
A silencer for a two-stroke motor of a power tool, comprising: a silencer inlet that adjoins a flow channel having a flow channel length to an outlet of a combustion chamber of the two-stroke motor; a first chamber having a first chamber depth, an end of the flow channel opposite to the silencer inlet opening into the first chamber; and a second chamber into which exhaust gas flows through a main outlet branched from the flow channel, the second chamber having an outlet from which the exhaust gas flows, wherein due to the inertial mass of the exhaust gas, the exhaust gas first flows into the silencer inlet, predominantly filling the first chamber, and after filling the first chamber, the exhaust gas flows back towards the combustion chamber, creating a counterpressure in a direction of the combustion chamber; wherein a total length including the flow channel length and the first chamber depth is less than a calculated length L determined in accordance with: L = c s · φ 12 · n ⁢ ⁢ in ⁢ ⁢ meters where c s =Speed of sound of the hot exhaust gas (m/s) φ=Crank angle in degrees from opening of the outlet of the combustion chamber to closing of the flow channel n=Motor Speed in 1 rev/min.