Exhaust system for two-stroke internal combustion engine

摘要

Each pre-manifold (27,28) expands in the exhaust flow direction (z) at its opening (35,36) to a wide clear section which is also retained for the main manifold (32). A catalyst unit (39) is built into the main manifold on the downstream side of the opening furthest from the exhaust outlet (40) and leaves part of the flow section free. A catalyst unit built into the upstream side of input (36) remote from the exhaust outlet extends over the entire section of this manifold (32). Each pair of adjoining engine cylinders (1-4) share respective manifold chambers (15,16) and shared pre-manifold ducts (27,28). Built into each channel (27,28,32) upstream of the respective catalyst unit is an Al-diffuser (30) with exhaust-flowed channels (34) designed in block form with channel-forming bores (34). The bores run straight and parallel and are of retained cylindrical section, the main faces (H) of the diffuser block to be at right angles to exhaust flow direction (z).