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.

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).

There is provided a muffling apparatus capable of sufficiently reducing noise, achieving space saving, and suppressing an increase in air-flow resistance in a suction passage. In a muffling apparatus including a resonator main body having a predetermined volume and a communication tube that allows the resonator main body to communicate with a suction passage of an internal combustion engine, the communication tube includes a first communication tube having one end that communicates with the suction passage, a second communication tube having one end that communicates with the resonator main body, and a continuous section that communicates with other ends of the first and second communication tubes, and a third communication tube is formed at the continuous section.

An air cleaner for an internal combustion engine is arranged to reduce intake noise. The air cleaner includes an air cleaner element for cleaning an intake air, and an elastic member for reducing intake noise by utilizing an inside space of the air cleaner. An inside space of the elastic member is in communication with the inside space of the air cleaner through a communication passage. Preferably, a surrounding space formed between the elastic member and a case portion for receiving the elastic member is opened to the outside.

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.

A turbocharger (1) having a turbine housing (2), a compressor housing (3) which has a compressor outlet (20), and a silencer (21) which is arranged on an end region (22) on the compressor outlet (20) and which has a silencer housing (23) in which an insert part (25) is arranged so as to form at least one buffer chamber (24) which is connected via at least one opening (26) to an air-guiding duct (27). The opening (26) has an edge (28) with a radially inner corner (29) which is designed so as not to have a sharp edge.

Various methods and systems are provided for reducing cylinder-to-cylinder variation in exhaust gas recirculation. In one embodiment, a system comprises a first cylinder group of an engine having a first number of cylinders, a second cylinder group of the engine having a second number of cylinders that is not an integer multiple of the first number of cylinders, and an exhaust system coupled to the first cylinder group and the second cylinder group. In at least one mode of operation, the exhaust system has exhaust ports of the first cylinder group fluidly coupled to an intake of the engine and exhaust ports of the second cylinder group fluidly decoupled from the intake.