A combined exhaust gas noise silencer consisting of a system of hollow elements with a mutual housing comprising a front face of the silencer connected to the supply pipe of exhaust gases, and a rear face of the silencer with an outlet from the rear face of the silencer, where the original—inlet exhaust gas (İ.sub.p) carrying a noise wave is divided into at least two flows—an exhaust gas flow (İ.sub.z) carrying a shifted noise wave with delayed wave length, and an exhaust gas flow (İ.sub.n) carrying a non-shifted noise wave, which are subsequently combined into a common exhaust gas flow (İ.sub.s).

The present disclosure provides a muffler system that can effectively reduce exhaust noises. The muffler system includes an exhaust passage and a first muffler. The exhaust passage is configured to allow a flow of an exhaust gas. The first muffler is an expansion chamber muffler and disposed in the exhaust passage. The first muffler is situated upstream of a first position in a flow direction of the exhaust gas. The first position is located away from an upstream end of the exhaust passage by one third of an entire length of the exhaust passage.

A vehicle exhaust system includes a first exhaust gas path and a second exhaust gas path. At least one valve is positioned within the first exhaust gas path and an active noise control system is associated with the second exhaust gas path. An example method includes, providing the first exhaust gas path with a first tailpipe having a first outlet and the second exhaust gas path with a second tailpipe having a second outlet separate from the first outlet. The valve and the active noise control system are controlled simultaneously to control noise generated by the vehicle exhaust system.

Disclosed is a sound-absorbing silencer having a diffuse reflection structure. The silencer includes a housing including an inlet and an outlet formed in respective ends thereof to allow noise to be introduced thereinto and discharged therefrom and a noise-attenuating unit disposed in the housing to attenuate noise through diffuse reflection and absorption of the noise. The noise-attenuating unit includes a first diffuse reflection pipe disposed in the housing while being spaced apart from the housing, at least one second diffuse reflection pipe accommodated in the first diffuse reflection pipe while being spaced apart from the first diffuse reflection pipe to form a noise-attenuating path therebetween so that noise is diffusely reflected and absorbed while flowing through the noise-attenuating path, and a sound-absorbing member disposed between the first diffuse reflection pipe and the housing and in the second diffuse reflection pipe to absorb noise diffusely reflected in the noise-attenuating path.

A combined exhaust gas noise silencer consisting of a system of hollow elements with a mutual housing comprising a front face of the silencer connected to the supply pipe of exhaust gases, and a rear face of the silencer with an outlet from the rear face of the silencer, where the originalinlet exhaust gas (?.sub.p) carrying a noise wave is divided into at least two flowsan exhaust gas flow (?.sub.z) carrying a shifted noise wave with delayed wave length, and an exhaust gas flow (?.sub.n) carrying a non-shifted noise wave, which are subsequently combined into a common exhaust gas flow (?.sub.s).