A filter muffler includes a front element, a rear element, and a plurality of damping elements arranged between the front element and the rear element, where the damping elements are arranged radially around a central axis of the filter muffler such that a flow channel is formed between adjacent damping elements, where respective outflow-side ends of the damping elements have a diffuser element which has an outflow-side tapering, and where an angle α between two opposite sides of the diffuser element is selected from a range of 1°≤α≤8°.

A high frequency attenuating device for an air flow induction system of a vehicle employing a thermoformed fibrous mat of any shape that fits robustly inside the duct. The dissipative nature of the fibrous mat helps in achieving broadband attenuation in the high frequency regime. The ability to manufacture the fibrous mat into any shape helps with restriction, targets different attenuation bands, and makes it more feasible to manufacture. Hybrid solutions are possible when combined with low frequency perforated silencers or high frequency QWT arrays injection molded onto them.

The invention relates to a method of operating a four stroke internal combustion engine system (1), the engine system (1) comprising:—a four stroke internal combustion engine (2) provided with an intake duct (5),—a turbo compressor (6″) arranged to compress intake flow in the intake duct (5), and—a displacement machine (7) provided in the intake duct (5) downstream the turbo compressor (6″), wherein the displacement machine (7) is arranged to displace intake flow from an inlet to an outlet thereof. The method comprises the step of: operating the displacement machine (7) in a first mode where a pressure ratio (PR) given by a pressure at the outlet of the displacement machine (7) divided by a pressure at the inlet of the displacement machine (7) is substantially equal to 1. The invention also relates to a four stroke internal combustion engine system arranged to be operated by the above method.

The invention relates to a method of operating a four stroke internal combustion engine system (1), the engine system (1) comprising:—a four stroke internal combustion engine (2) provided with an intake duct (5),—a turbo compressor (6″) arranged to compress intake flow in the intake duct (5), and—a displacement machine (7) provided in the intake duct (5) downstream the turbo compressor (6″), wherein the displacement machine (7) is arranged to displace intake flow from an inlet to an outlet thereof. The method comprises the step of: operating the displacement machine (7) in a first mode where a pressure ratio (PR) given by a pressure at the outlet of the displacement machine (7) divided by a pressure at the inlet of the displacement machine (7) is substantially equal to 1. The invention also relates to a four stroke internal combustion engine system arranged to be operated by the above method.

An air cleaner of an internal combustion engine is provided with a first housing including an inlet, a second housing including an outlet, and a filter element located between the first housing and the second housing. A Helmholtz resonator is arranged inside the first housing. An upright wall projects from a bottom wall of the first housing toward the filter element and extends in an axial direction of the inlet. The upright wall forms a chamber of the Helmholtz resonator. A noise-absorption region is defined by the upright wall, a side wall of the first housing, the bottom wall, and the filter element. The noise-absorption region leads to the inlet and extends in the axial direction.

The invention relates to a filter muffler (10) comprising a front element (11), a rear element (12), and a plurality of damping elements (20) which are arranged between the front element (11) and the rear element (12). The damping elements (20) are arranged radially about a central axis (16) of the filter muffler such that a flow channel (30) is formed between each pair of adjacent damping elements. The respective downstream ends (22) of the damping elements (20) each have a diffuser element (23) which has a downstream tapering. An angle between two opposing sides of the diffuser element (23) is selected from a range of 18.

A high frequency attenuating device for an air flow induction system of a vehicle employing a thermoformed fibrous mat of any shape that fits robustly inside the duct. The dissipative nature of the fibrous mat helps in achieving broadband attenuation in the high frequency regime. The ability to manufacture the fibrous mat into any shape helps with restriction, targets different attenuation bands, and makes it more feasible to manufacture. Hybrid solutions are possible when combined with low frequency perforated silencers or high frequency QWT arrays injection molded onto them.

A construction machine includes: a partition member partitioning an accommodation space in an engine compartment into a main chamber and an intake chamber while having an inter-chamber opening; a fan disposed in the main chamber to generate cooling air flowing through an air intake opening, the intake chamber, the inter-chamber opening, and the main chamber in this order by sucking air in the engine compartment in a suction direction; a duct joined to an outer wall to enclose the air intake opening and including an inner peripheral surface enclosing a duct passage leading to the air intake opening and an outer peripheral surface. The duct extends in a duct extension direction different from the suction direction of the fan, disposed in the intake chamber to define a duct surrounding space around the outer peripheral surface of the duct.

An air cleaner of an internal combustion engine is provided with a first housing including an inlet, a second housing including an outlet, and a filter element located between the first housing and the second housing. A Helmholtz resonator is arranged inside the first housing. An upright wall projects from a bottom wall of the first housing toward the filter element and extends in an axial direction of the inlet. The upright wall forms a chamber of the Helmholtz resonator. A noise-absorption region is defined by the upright wall, a side wall of the first housing, the bottom wall, and the filter element. The noise-absorption region leads to the inlet and extends in the axial direction.

A throttle body adapter connects a throttle body and an air intake manifold spaced from the throttle body in a marine engine. The throttle body adapter has an air passage having an inlet and an outlet of different shapes. The throttle body adapter has threaded openings which allow a fuse box, an electronic control module, a hose fitting and a mounting bracket for a beauty cover to be mounted to the throttle body adapter with threaded fasteners. The throttle body adapter further comprises a threaded opening adapted to receive an air inlet temperature sensor.