A fracturing device, including a power unit, wherein the power unit comprises a muffling compartment, a turbine engine, an air intake unit, and a starter; the air intake unit is communicated with the turbine engine through an intake pipe, and configured to provide a combustion-supporting gas to the turbine engine; the air intake unit is located at the top of the muffling compartment, the muffling compartment comprises an accommodation space, the turbine engine and the starter are located in the accommodation space, and the starter is configured to start the turbine engine, the starter comprises a first electric motor.

A sound suppression apparatus for installation inside a gas transport duct is provided. The sound suppression apparatus comprises a resistive sound-absorbing element (110) and a housing providing a reactive sound-attenuating element (130) communicating with a surrounding of the apparatus via opening in an outer surface of the housing. An outer surface of the sound suppression apparatus comprises an outer surface of the resistive sound-absorbing element and the outer surface of the housing. A gas transport duct comprising the sound suppression apparatus is also provided.

A sound suppression apparatus for installation inside a gas transport duct is provided. The sound suppression apparatus comprises a resistive sound-absorbing element (110) and a housing providing a reactive sound-attenuating element (130) communicating with a surrounding of the apparatus via opening in an outer surface of the housing. An outer surface of the sound suppression apparatus comprises an outer surface of the resistive sound-absorbing element and the outer surface of the housing. A gas transport duct comprising the sound suppression apparatus is also provided.

Generation of a balloon-shaped air bubble is suppressed. A foam molded article according to a mode of the present disclosure is characterized in that in a situation of being divided into two equal parts in the thickness direction T of the foam molded article, the average cell diameter 1 in the thickness direction T on the inner surface side A of the foam molded article is 1.2 times ((1/1)=1.2) or greater of the average cell diameter 1 in the thickness direction T on the outer surface side B of the foam molded article and that the surface roughness Sm of the inner surface of the foam molded article is 1000 m or greater.

A vehicle muffler may include first to third baffles to partition the internal to a housing into first to fourth chambers; a suction tube penetrating the housing, the first to third baffles in series, having an inlet at outside of the housing and an outlet in the fourth chamber, and having through-holes in the section locating in the first to third chambers; a first discharge tube penetrating the first and second baffles and the housing in series, having an inlet on the first baffle, and an outlet at outside of the housing; a second discharge tube penetrating the second and third baffles, and the housing in series, having an inlet in the second chamber, and an outlet at the outside of the housing; and a connection tube penetrating the second and third baffles in series, having an inlet in the second chamber, and an outlet in the fourth chamber.

A vehicle muffler may include first to third baffles to partition the internal to a housing into first to fourth chambers; a suction tube penetrating the housing, the first to third baffles in series, having an inlet at outside of the housing and an outlet in the fourth chamber, and having through-holes in the section locating in the first to third chambers; a first discharge tube penetrating the first and second baffles and the housing in series, having an inlet on the first baffle, and an outlet at outside of the housing; a second discharge tube penetrating the second and third baffles, and the housing in series, having an inlet in the second chamber, and an outlet at the outside of the housing; and a connection tube penetrating the second and third baffles in series, having an inlet in the second chamber, and an outlet in the fourth chamber.

A method of forming an acoustic volume in a vehicle component includes providing a vehicle frame member that includes a hollow cavity, forming an internal shell that is completely sealed and which includes at least one connection point, and locating the internal shell within the hollow cavity. At least one exhaust system component is connected to the internal shell at the connection point to provide at least one acoustic volume.

A method of forming an acoustic volume in a vehicle component includes providing a vehicle frame member that includes a hollow cavity, forming an internal shell that is completely sealed and which includes at least one connection point, and locating the internal shell within the hollow cavity. At least one exhaust system component is connected to the internal shell at the connection point to provide at least one acoustic volume.

A golf car includes an engine and a shroud that covers a cylinder body. The shroud communicates with a muffler cover, which covers a muffler. A silencer is provided at an outlet of the muffler. An elastic exhaust duct is connected to an exit end portion of the muffler cover. An undercover is located lower than the engine, and defines an underside of an engine room. The undercover includes an opening at a more rearward position than the muffler in a side view. The exhaust duct is routed above the undercover, includes a rearward end portion at the opening, and is fitted to the opening. Holders hold sound absorbing members on an inner circumferential surface of the exhaust duct.