An intake manifold is for a marine engine having a throttle for controlling flow of intake air to the marine engine. The intake manifold has a plenum for receiving the intake air from the throttle, a plurality of intake runners which extends from upstream ends for receiving the intake air from the plenum to downstream ends for discharging the intake air to the marine engine, and a quarter wave resonator extending from an open end coupled to the plenum to a closed end, the quarter wave resonator having a tuned elongated cavity configured to attenuate sound emanating from the marine engine via the plurality of intake runners.

An air induction system includes an air duct and an air permeable membrane. The air duct is configured to deliver intake air to an engine. The air duct includes a cylindrical wall defining a bore and an enclosure projecting from an outer radial surface of the cylindrical wall and defining a cavity therein. The cylindrical wall has an opening extending therethrough that enables airflow from the bore to the cavity in the enclosure. The air permeable membrane is configured to cover the opening in the cylindrical wall.

An air blower has an inlet muffler and an outlet muffler to reduce the noise of the air blower during operation. Each of the mufflers may have two sections. One section is configured to attenuate high frequency noise and the other section is configured to attenuate lower frequency noise. A tubular internal wall in each of the mufflers defines the through passage for each of the mufflers. A noise absorbent material may be fitted about the tubular wall within each muffler. A plurality of holes are formed along the tubular wall of each through passage to expose the through passage to the noise absorbent material. A heater plenum may be interposed between the blower plenum and the outlet muffler to heat the air from the blower plenum. A filter at the input muffler filters the air sucked into the air blower.

An air intake system for a marine engine has a throttle body and a throttle plate that is rotatably supported within the throttle body. The throttle plate is rotatable to regulate air flow through the throttle body from a first region on a first side of the throttle plate to a second region on a second side of the throttle plate. An air conduit has an air conduit inlet and an air conduit outlet. A noise cancelling device comprises a pass-though chamber. The pass-through chamber has a chamber inlet that receives the air flow from the air conduit, a chamber outlet that discharges the air flow to the idle air control valve, and a pass-through interior between the chamber inlet and chamber outlet. The pass-though chamber is configured to cancel noise emanating from the idle air control valve.

An engine cover covers an engine; and an intake pipe through which the air is introduced into the engine. An intake silencer is provided adjacent to the intake pipe and suppresses air pressure fluctuations of air in the intake pipe to reduce intake sound. A portion of the intake silencer is covered with the engine cover, and a remaining portion is exposed with respect to the engine cover. An advantage is that secondary noise generated by the intake silencer and a temperature increase of air suctioned into the engine are simultaneously suppressed.

A silencer for reducing gas noise in a combustion engine intake system has a tubular casing with a first casing part and a second casing part connected to each other by a weld seam to form an outer casing wall, wherein the weld seam is a part of the outer casing wall. A third part for compensating gas noise is positioned inside the tubular casing. The third part is arranged in the tubular casing such that an annular cavity is formed by the third part and the outer casing wall. A weld flash protrudes from an inner surface of the outer casing wall into the annular cavity and is contained therein. The silencer is produced in a single welding process in which the first and second casing parts are connected to each other to form the outer casing wall and the third part is connected to the tubular casing.

The invention concerns a device (1) for attenuating intake noise and radiated noise that comprises an internal gas delivery conduit (2) linked to a combustion engine, the conduit (2) having a peripheral wall (23) on at least one portion of which there is disposed at least one element porous to air (4), sound attenuation means comprising at least one tube (3) disposed in the delivery conduit, at least one peripheral chamber (5) being delimited inside the conduit (2) between the tube (3) and the peripheral wall (23) of the conduit (2), the tube (3) comprising at least one portion having an opening (30) allowing the inside of the tube (3) to communicate with the peripheral chamber (5).

A system for reducing noise associated with a compressor of an engine system comprises an intake manifold and a resonator comprising an outlet. The resonator is coupled to, and is positioned adjacent to, the intake manifold. An outlet pipe is in fluid communication with the outlet and the compressor, and a length of the outlet pipe extends from the outlet to the compressor. Positioning the resonator adjacent to the intake manifold reduces the length of the outlet pipe so as to reduce noise associated with air flowing through the outlet pipe.

An engine intake air duct 1 has an intake portion 10 that extends along a first center line A, and a main duct portion 20 that extends along a second center line B. The main duct portion 20 has a merging portion 50, a discharge opening 21, and an extending portion 40 that extends from the merging portion 50 towards an opposite end to the discharge opening 20. A reflecting wall 41 is provided at an end face of the extending portion 40. The intake portion 10 merges with the main duct portion 20 in such a way that the first center line A is directed towards a downstream end of the main duct portion 20.

An engine cover covers an engine; and an intake pipe through which the air is introduced into the engine. An intake silencer is provided adjacent to the intake pipe and suppresses air pressure fluctuations of air in the intake pipe to reduce intake sound. A portion of the intake silencer is covered with the engine cover, and a remaining portion is exposed with respect to the engine cover. An advantage is that secondary noise generated by the intake silencer and a temperature increase of air suctioned into the engine are simultaneously suppressed.