Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
  • F01N1/00—Silencing apparatus characterised by method of silencing
  • F01N1/003—Silencing apparatus characterised by method of silencing by using dead chambers communicating with exhaust gas flow passages
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
  • F01N1/00—Silencing apparatus characterised by method of silencing
  • F01N1/08—Silencing apparatus characterised by method of silencing by reducing exhaust energy by throttling or whirling
  • F01N1/089—Silencing apparatus characterised by method of silencing by reducing exhaust energy by throttling or whirling using two or more expansion chambers in series

Definitions

• the silencer is composed by a cylindrical enclosure (1) - wi preferably a near circular or elliptic cross section-, closed both ends by end caps (2), through which the up- (3) and do stream pipes (4) pass.
• This enclosure is subdivided longitudinally into a high numb of shallow cells, by transversal diaphragms (5).
• the (exhaust) gas flows through (circular) holes in t diaphragms, approx. the same diameter as the up- a downstream pipe diameter, and aligned with these.
• a high passage rate perforated pipe or mesh (6) may or may n be running through the diaphragm holes (fig. 1 & 2). T perforated pipe would facilitate the assembly and impro further the gas flow, and heat exchange.
• the fishbone subdivision may be obtained by t introduction of a cartridge (ceramic, sintered, etc.) (fig 5 p. 1 or the silencer might be produced as a monolithic constructi
• the shallowness of the cells can be defined by the ratios ai and ai which should be d t respectively ⁇ ⁇ .o and ⁇ o.5 where t is the mean enclosure transversal dimension and d t diaphragm aperture (fig 1-6, p. 9-11); ai, the axial dimension the respective cells, can be choosen constant or varia optimising the silencer acoustic performance for its specific ta (noise reduction for particular frequency ranges). See Fig. 3 p. 10.
• Silencer design is still largely empirical, due to its diffic mathematical analysis. For silencers of this new configurati tests can easily be set up to find out the optimum design. T comes down to determining ai, for given overall dimensions. DESCRIPTION
• the new silencer is made of one single materi (fig. 1-4, p. 9-10; fig. 6, p. 11) or, alternatively, is fitted with ( cartridge(s), which is (are) easily introduced or exchanged f overhaul (Fig. 5 p. 11).
• this concept implies a generally cylindric shape.
• Cross sections should be near circular or elliptic, while they a acoustically the stiffest, and allow the thinnest mantle materi thickness, avoiding shell noise.
• the diaphragms should be stiff enough and well clamped, not transmit noise to the next cell by vibrating themselves. They c be doubly curved (stamped) for maximum stiffness and lightnes See fig. 2 p. 9.
• Their clamping can be by heat-shrinking of the mantle arou them (either of a complete cylinder which is heated, or by t shrinkage of 1 or 2 longitudinal welds, (1 open shell or 2 pa shells) f.i.
• the gas flow channel can be concentric but may be eccentr (fig. 3 & 4 p. 10). DESCRIPTION
• the author proposes thus an inversion of the (car) muffler design and selection procedure : instead of filling up available space under the car with custom designed volumes of mufflers, the car designers would accept from the start that they be cylindrical, with a limited but handsome number of standardised cross-sections and pipe eccentricities to choose from, and provide space for these under the body.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Exhaust Silencers (AREA)

Applications Claiming Priority (1)

Publications (2)

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ID=8165688

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Country Status (4)

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Family Cites Families (4)

• 1992
  • 1992-10-02 EP EP95933221A patent/EP0708880B1/de not_active Expired - Lifetime
  • 1992-10-02 AT AT95933221T patent/ATE168167T1/de not_active IP Right Cessation
  • 1992-10-02 WO PCT/EP1992/002290 patent/WO1993019287A1/en not_active Ceased
  • 1992-10-02 AU AU26799/92A patent/AU2679992A/en not_active Abandoned

Non-Patent Citations (1)

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