Abstract: A suction silencer for suppressing generation of noise caused by gas or air sucked by a machine such as a compressor, internal combustion engine or the like. The suction silencer has amounting seat by which it is mounted on the suction side of a machine such as an internal combustion engine. The mounting seat has an opening leading to the suction port of the machine. An inversed conical surface protrudes from the peripheral edge of the opening. A lid member is attached to cover the inversed conical surface such that a small gap is left between the inner surface of the lid member and the large-diameter end of the inversed conical surface. The lid member has an inversed conical member which projects into the space defined by the conical surface so that an annular passage is formed between the inversed conical surface and the peripheral surface of the inversed conical member.

Abstract: An exhaust muffler for a two-cycle opposed cylinder engine of simultaneous ignition type having two cylinders opposing to each other in the horizontal direction. The muffler has conical members disposed to oppose to exhaust ports of the cylinders, the exhaust ports being arranged in a side-by-side relation. The conical members form conical annular discharge passages leading from respective exhaust ports. The discharge passages have flattened peripheral outlets of different opening areas. The flows of the exhaust gas from respective cylinders are introduced through the flattened peripheral outlets of the discharge passages into a common diffusion chamber, so that the attenuation of the pressure waves and release of heat of exhaust gas are promoted to reduce the exhaust noise of the engine.