Abstract: An air intake system for intake air of an internal combustion engine comprising a filter insert (19) in a housing (10) connected to the air conducting system by a plurality of inlets (13) and an outlet (22). The air inlets are provided with individual intake nozzles or fittings and lead to a single common air chamber (20) in the filter housing. The inlets (13) can be individually opened and closed by flap valves (24), thereby allowing the acoustics to be influenced favorably and enabling, for example, the respective intake fittings to be connected or disconnected depending on the temperature. The intake system requires only a limited number of components, and the design of the preferably wedge-shaped air chamber minimizes flow losses in the housing, which in turn decreases the intake noise. Shunt resonators (28) can also be formed using cover elements (29) and (30).

Abstract: A method and apparatus for actively influencing the intake noise of an internal combustion engine. The apparatus comprises a controller (7) which senses the actual noise (I) via a microphone (16) and compares the actual noise with a reference noise signal which depends on the engine speed D and at least one further engine parameter P, such as, for example, the throttle (12) position. A comparison signal V generated by comparing the actual noise to the reference noise value is used to adjust a control signal Asum, which also depends on the engine speed D. The control signal is fed to an electromechanical transducer (14) which generates a correcting noise (20) which is superimposed on the intake noise (21) to produce the resultant actual noise (22), which should correspond as closely as possible to the reference noise value.

Abstract: An air intake system for intake air of an internal combustion engine comprising a filter insert (19) in a housing (10) connected to the air conducting system by a plurality of inlets (13) and an outlet (22). The air inlets are provided with individual intake nozzles or fittings and lead to a single common air chamber (20) in the filter housing. The inlets (13) can be individually opened and closed by flap valves (24), thereby allowing the acoustics to be influenced favorably and enabling, for example, the respective intake fittings to be connected or disconnected depending on the temperature. The intake system requires only a limited number of components, and the design of the preferably wedge-shaped air chamber minimizes flow losses in the housing, which in turn decreases the intake noise. Shunt resonators (28) can also be formed using cover elements (29) and (30).

Abstract: An enclosure for an air aspirating machine, such as a compressor 11 for a fuel cell drive 13, which represents a closed volume, so that said volume can be used acoustically for the air that is being drawn in. An air intake 17 is extended into the enclosure 12, which is made of a sound damping and absorbing material 18, so that the resonant cavity 19 acts as a series resonator. The air is drawn in via an air inlet 21 of the compressor 11. Alternatively, the resonant cavity can also be used as a parallel resonator in that the intake path for the air is sealed within the enclosure 12 and is provided only with sound communicating openings to the resonant cavity.

Abstract: A method and apparatus for actively influencing the intake noise of an internal combustion engine. The apparatus comprises a controller (7) which senses the actual noise (I) via a microphone (16) and compares the actual noise with a reference noise signal which depends on the engine speed D and at least one further engine parameter P, such as, for example, the throttle (12) position. A comparison signal V generated by comparing the actual noise to the reference noise value is used to adjust a control signal Asum, which also depends on the engine speed D. The control signal is fed to an electromechanical transducer (14) which generates a correcting noise (20) which is superimposed on the intake noise (21) to produce the resultant actual noise (22), which should correspond as closely as possible to the reference noise value.

Abstract: The invention relates to a silencer. The silencer includes a sound conducting channel having two ends. An injection molded part is arranged between the two ends of the sound conducting channel and includes a plurality of pipe elements. A shunt resonator is arranged in fluid communication with the sound conducting channel by way of openings formed in the plurality of pipe elements. The shunt resonator defines a volume formed by two housing parts which are joined together. By varying the number, position, length and diameter of the pipe elements in the silencer, the silencer is capable of achieving silencing gains in different frequency ranges.

Abstract: An enclosure for an air aspirating machine, such as a compressor 11 for a fuel cell drive 13, which represents a closed volume, so that said volume can be used acoustically for the air that is being drawn in. An air intake 17 is extended into the enclosure 12, which is made of a sound damping and absorbing material 18, so that the resonant cavity 19 acts as a series resonator. The air is drawn in via an air inlet 21 of the compressor 11. Alternatively, the resonant cavity can also be used as a parallel resonator in that the intake path for the air is sealed within the enclosure 12 and is provided only with sound communicating openings to the resonant cavity.

Abstract: An air flow device in which there are adjusters in the flow path to alter the flow geometry of the air. The total cross section of the flow path is divided into individual flow channels (15, 16, 17) or tube sections (1, 3, 4) one inside the other, and there are mechanisms or adjusters (13, 14) by which the flow paths in the individual flow channels (15, 16, 17; 1, 3, 4) can be controlled. In a preferred embodiment there are three flow channels (15, 16, 17) the ends of which are connected to an internal aperture (22 to 27) in the adjusters (13, 14).

Abstract: An air intake system for an internal combustion engine in which the air, which is taken in, passes via an air filter (3) to the internal combustion engine through an intake passage within which a damping cavity volume (5) is provided which acts as a Helmholz resonator. The effective damping cavity volume (5) is sized such that a given noise frequency range can be attenuated, and in order to achieve optimum noise suppression, at least a partial flow of air passes through the damping cavity volume, and the size of the effective damping cavity volume (5) through which the air passes can be varied by reversible switches and/or valves.

Abstract: An intake system for an internal combustion engine in which the intake system includes an air inlet (10), an air filter (11), a main flow duct (12) and individual ducts (13 to 16) leading from the main flow duct to the internal combustion engine cylinders. The intake system includes at least one shunt resonator (18) which includes at least one neck (20) and a resonator volume (19), the length and/or cross section of the neck (20) being variable.

Abstract: A tube, particularly suitable for use as a part of the intake manifold of an internal-combustion engine, having an inside diameter which can be changed as a function of the operating condition of the internal-combustion engine.

Abstract: The proposal is for a suction pipe consisting of a number of individual suction pipes (10, 16, 17, 18) connected on the intake side to a manifold (11). According to the invention, the manifold is made in one piece with the suction pipes by the blow-molding method.