Sound waves of an amplitude having a waveform (first value as a function of time and a first maximum) pass into a manifold, which subdivides flow and sound into multiple paths of differing length, yielding transit times offsetting the arrival of each instance of the waveform at an outlet or exit. This minimizes the addition of energy (sound volume, amplitude) arriving at the exit or terminus from each path. Amplitude is thereby reduced (although the waveform shape remains), repeated and offset by the transit time delays of paths discharging at the terminus. One may select the number of paths based on a desired reduction in the sound amplitude. That number is approximately inversely proportional to the ratio of the reduction. For example, six unique paths in an experiment reduced original amplitude (sound volume) to a sixth at an exit.

A muffler for use with an internal combustion engine is provided. The muffler includes a first tube configured to receive a first exhaust stream. The first tube includes a first inlet portion, a first outlet portion spaced apart from the first inlet portion, and a first intermediate portion extending between the first inlet portion and the first outlet portion. The muffler also includes a second tube configured to receive a second exhaust stream. The second tube includes a second inlet portion, a second outlet portion spaced apart from the second inlet portion, and a second intermediate portion extending between the second inlet portion and the second outlet portion. The first intermediate portion and the second intermediate portion cross each other, are at least partially stacked on each other, and are in fluid communication with each other.

A muffler for use with an internal combustion engine is provided. The muffler includes a first tube configured to receive a first exhaust stream. The first tube includes a first inlet portion, a first outlet portion spaced apart from the first inlet portion, and a first intermediate portion extending between the first inlet portion and the first outlet portion. The muffler also includes a second tube configured to receive a second exhaust stream. The second tube includes a second inlet portion, a second outlet portion spaced apart from the second inlet portion, and a second intermediate portion extending between the second inlet portion and the second outlet portion. The first intermediate portion and the second intermediate portion cross each other, are at least partially stacked on each other, and are in fluid communication with each other.

The encased exhaust is a traditional aftermarket expansion chamber muffler system for a two stroke engine encompassing a duct fan/propeller. The propeller is mounted directly to the engine's driveshaft, eliminating reduction gears and belts allowing for more airflow and less weight. This eliminates the muffler and replaces the cage on a paramotor, allowing for more airflow through the funneled air duct. The configuration of these two functions exists but not in this sequence, that is what makes this product unique.

The encased exhaust is a traditional aftermarket expansion chamber muffler system for a two stroke engine encompassing a duct fan/propeller. The propeller is mounted directly to the engine's driveshaft, eliminating reduction gears and belts allowing for more airflow and less weight. This eliminates the muffler and replaces the cage on a paramotor, allowing for more airflow through the funneled air duct. The configuration of these two functions exists in a particular sequence.

The encased exhaust is a traditional aftermarket expansion chamber muffler system for a two stroke engine encompassing a duct fan/propeller. The propeller is mounted directly to the engine's driveshaft, eliminating reduction gears and belts allowing for more airflow and less weight. This eliminates the muffler and replaces the cage on a paramotor, allowing for more airflow through the funneled air duct. The configuration of these two functions exists in a particular sequence.

A diffuser is configured for use on a vehicle having an engine and an exhaust pipe. The diffuser includes a conduit with a first end configured to receive exhaust gases from the engine. A diffusion fitting is coupled to a second end of the conduit to receive exhaust gases discharged from the conduit. The diffusion fitting has an outer wall that includes a curved surface. The curved surface is configured to guide the exhaust gases discharged from the conduit about an axis so that exhaust gases exit a first side of the diffusion fitting rotating about the axis.

A sound absorbing structure includes a vehicle structure having a surface and at least one acoustic scatterer coupled to the surface. The at least one acoustic scatterer has a resonant frequency. The at least one acoustic scatterer has an opening and at least one channel. The at least one channel has a channel open end and a channel terminal end, the channel open end being in fluid communication with the opening. The sound absorbing structure may be configured to absorb sound waves at a certain frequency generated by a noise source. The certain frequency may be substantially similar to the resonant frequency of the at least one acoustic scatterer.

Provided is an exhaust fumes reduction device for an internal combustion engine. The device reduces the generation of exhaust fumes and improves output and fuel efficiency by smoothing the discharge flow of exhaust gas in a state additionally mounted at the end of an exhaust line of an internal combustion engine. The exhaust fumes reduction device includes; a housing pipe connected to the end of the exhaust port to discharge exhaust gas; a vortex pipe mounted inside the housing pipe to increase the speed of the exhaust gas introduced into the housing pipe and discharge the exhaust gas spirally; and an external pipe mounted on the outside of the housing pipe and in communication with the housing pipe to allow the outside air to flow in and to assist the smooth discharge of exhaust gas discharged to the housing pipe.

A noise abatement system including at least one fluid circulation chamber to receive at least one flow of fluid; at least one vorticity-inducing component adjacent to the at least one fluid circulation chamber, the at least one vorticity-inducing component to redirect the at least one flow of fluid tangentially to an inside perimeter wall of the at least one fluid circulation chamber to create fluctuations in a flow and pressure of the fluid causing increased and variable vorticity within the at least one fluid circulation chamber; and at least one vorticity-interaction region in communication with the at least one vorticity-inducing component to attenuate acoustics caused by the at least one flow of fluid.