Exhaust silencing system

Patent · Tue Jun 24 04:00:00 EDT 1986

OSTI ID:5589746

Abe, T; Aoki, Y

An exhaust silencing system is described for an automotive internal combustion engine which consists of: a sound absorbing tube formed of an inherently gas permeable porous material having first and second opposite end sections, the sound absorbing tube being connected at the first end section with the rear end of a tailpipe and an exhaust system of the engine, the second end section of the sound absorbing tube remaining open, the sound absorbing tube having an inner diameter substantially equal to or greater than that of the tailpipe, the porous material having the characteristic of absorbing and attenuating exhaust noise including high frequency exhaust noise by permitting a portion of exhaust gas traveling through pores of the tube forming an inherent characteristic of the tube material to be dissipated through the porous material of the tube so that a boundary layer tending to be formed on an inner wall surface of the tube due to gas viscosity is attenuated so that a maximum flow velocity and velocity gradient of a resulting jet generated downstream of an exhaust outlet defined by the second end section is reduced to a level lower than the noise level of exhaust gases discharged into ambient atmosphere directly from a tailpipe formed without the sound absorbing tube.

• Assignee: Nissan Motor Co., Ltd.
• Patent Number(s): US 4596306
• OSTI ID: 5589746
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330100* -- Internal Combustion Engines
BOUNDARY LAYERS
ENGINES
EXHAUST GASES
EXHAUST SYSTEMS
FLOW RATE
FLUIDS
GASEOUS WASTES
GASES
HEAT ENGINES
INTERNAL COMBUSTION ENGINES
LAYERS
MATERIALS
NOISE POLLUTION ABATEMENT
PERMEABILITY
PIPES
POLLUTION ABATEMENT
POROUS MATERIALS
VEHICLES
WASTES