Intake noise suppression techniques for a forced-induction engine having a low pressure exhaust gas recirculation (LPEGR) system configured to recirculate exhaust gas produced by the engine to an intake system of the engine via an EGR port comprise receiving, from a mass air flow (MAF) sensor of the engine, a MAF signal indicative of measured airflow through the intake system, detecting, based on the MAF signal, intake system conditions that are indicative of audible noise, and in response to detecting the detected intake system conditions that are indicative of audible noise, at least partially closing a differential pressure (dP) valve to mitigate or eliminate the intake system conditions and the corresponding audible noise, wherein the MAF sensor is disposed in the intake system upstream from the dP valve.

The invention relates to an engine air filter unit for a vehicle (1) that is designed to supply filtered air to an internal combustion engine of the vehicle (1). The engine air filter unit (10) comprises a main filter (14), a mounting base (15) to secure the engine air filter unit (10) on at least one body panel (7, 71, 72) of the vehicle, a pre-separator fluidically connected to the main filter. The main filter (14) is arranged on a side of the mounting base (15) and the pre-separator (18) is arranged on the opposite side of the mounting base (15). The pre-separator housing is at least partly formed by the mounting base (15) and an air duct (19) extends through the mounting base (15) to fluidically connect the pre-separator to the filtration chamber.

In an air cleaner, an air cleaner case having an upper opening which opens upward is formed. The air cleaner case is formed of a front wall, a rear fender, and right and left side covers. The upper opening is closed by a seat. A sound absorbing member is bonded to a bottom plate of the seat and housed in an air cleaner space. The intake noise in the air cleaner is absorbed by the sound absorbing member.

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.

This outboard machine has: a V-type engine (engine) in which a plurality of cylinders are arranged in a V-shape when viewed in a plan view; and a cover that covers the engine. The engine has a plurality of intake ports that form pairs in a V-shape inside the plurality of cylinders in a plan view and a concave space is formed between the plurality of intake ports. The cover has therein an intake path that guides air to the intake port, and is also provided with, at a position that is adjacent to the intake path and enters the concave space, a silencer that attenuates the sound during intake.

This outboard machine has: a V-type engine (engine) in which a plurality of cylinders are arranged in a V-shape when viewed in a plan view; and a cover that covers the engine. The engine has a plurality of intake ports that form pairs in a V-shape inside the plurality of cylinders in a plan view and a concave space is formed between the plurality of intake ports. The cover has therein an intake path that guides air to the intake port, and is also provided with, at a position that is adjacent to the intake path and enters the concave space, a silencer that attenuates the sound during intake.

A compression device includes a centrifugal compressor and a silencer. The centrifugal compressor includes a compressor assembly bolt fastening an inlet side of an inlet guide to a scroll casing. The silencer includes: a first side wall extending in a direction intersecting with a rotational axis of an impeller; an annular second side wall provided between the first side wall and the centrifugal compressor and surrounding the rotational axis; at least one silencer element provided in an ambient-air introduction space formed between the first side wall and the second side wall for guiding an ambient air to the inlet guide; and a silencer assembly bolt extending from the first side wall to the scroll casing in a direction along the rotational axis of the impeller and fastening the first side wall, the second side wall, and the scroll casing.

An intake plenum is for a marine engine, the marine engine having first and second throttle devices for controlling flow of intake air to the marine engine. The intake plenum has an airbox providing an expansion volume, first and second inlets that convey the intake air in parallel to the expansion volume, first and second outlets that convey the intake air in parallel from the expansion volume to the first and second throttle devices, and first and second Helmholtz-style attenuator devices located at the first and second outlets, respectively. Together the first and second inlets, expansion volume, and first and second Helmholtz-style attenuator devices are configured to attenuate different frequencies of sound emanating from the marine engine via the first and second outlets.

A supercharger assembly comprises a housing, a rotor bore with an outer wall, an outlet in an outlet plane, an inlet in an inlet plane perpendicular to the outlet plane, and an outlet divider wall. The supercharger assembly comprises a first recess, a first perforated material covering the first recess, and an outlet resonator. The first recess is separated from the outlet by the outlet divider wall. The first recess is located between the outer wall and the first perforated material.

In an engine compartment, a separation wall is provided between an intake pipe, which runs around to a rear side of the engine from a lateral side of the engine, and the engine. On an outer side of this separation wall, a travel wind guide having a vertical wall portion that opposes the separation wall with the intake pipe being therebetween is provided. The travel wind guide guides vehicle travel wind that is introduced into the engine compartment in a manner to cause the vehicle travel wind to flow along the intake pipe on the outer side of the separation wall.