A method of generating a drive signal for a loudspeaker in an exhaust system of an engine of a vehicle or inside or outside a passenger cell includes providing a predetermined source signal for a desired additional sound in a time domain comprising a plurality of signal components of different frequencies; analyzing the source signal based on a phase of the source signal and/or a phase of at least one oscillation in the source signal; identifying a phase of engine noise and/or a phase of at least one oscillation existing in engine noise; shifting the phases of the source signal and/or the oscillation existing in the source signal based on phases identified in engine noise and/or in oscillation existing in engine noise, the relationship of phases of individual oscillations of the source signal among each other being preserved; and generating the drive signal based on the phase-shifted source signal.

In a method of influencing the exhaust noise of a motor vehicle, a control unit generates noise package signals, the control unit transmits the noise package signals individually or so as to superimpose a basic signal to a loudspeaker associated with an exhaust branch of the motor vehicle, and the loudspeaker converts the individual noise package signals or the basic signal superimposed with the noise package signals into sound waves, with individual noise package signals being emitted by the loudspeaker as time-limited sound wave packages, so-called noise packages. Furthermore, an exhaust system is shown.

The various embodiments set forth an active noise cancellation system that includes a source separation algorithm. The source separation algorithm enables the identification of acoustic inputs from a particular sound source based on a reference signal generated with one or more microphones. Consequently, the identified acoustic inputs can be cancelled or damped in a targeted listening location via an acoustic correction signal, where the acoustic correction signal is generated based on a sound source separated from the reference signal. Advantageously, the reference signal can be generated with a microphone, even though such a reference signal may include a combination of multiple acoustic inputs. Thus, noise sources that cannot be individually measured, for example with an accelerometer mounted to a vibrating structure, can still be identified and actively cancelled.

A connection pipe (7), for the fluidic connection of a muffler housing (5) of an active muffler (4) with an exhaust gas-carrying pipe (3) of an exhaust line (2) of an exhaust system (1) for an internal combustion engine, of a motor vehicle, has a pipe wall (8), which envelopes a connection space (9) leading from the muffler housing to the exhaust pipe. A cooling pipe (14), through which a coolant can flow, has an inlet section (15) and an outlet section (16) and is arranged in the connection space. The inlet section (15) passes through the pipe wall (8), whereby a coolant inlet (17), through which coolant can enter the cooling air pipe, is arranged outside the connection pipe (7). The outlet section passes through the pipe wall, whereby a coolant outlet (19), through which coolant can escape from the cooling pipe, is arranged outside the connection pipe (7).

A device includes a housing and a core configured to be secured within the housing. The core includes a microphone configured to detect a sound signal. The core also includes a control board configured to generate a noise-canceling sound signal based on the sound signal and a set of transfer functions. The core further includes a speaker configured to deliver the noise-canceling sound signal. The device also includes a fastener configured to connect the housing to an air filter of an intake vent of an enclosure of a power generation unit.

A sound system for a motor vehicle exhaust gas system for emitting emulated engine sounds, including at least one loudspeaker and at least one housing accommodating at least one loudspeaker. The housing is mounted separately from a motor vehicle exhaust gas system in terms of the routing of an exhaust gas flow, at least one sound guidance tube having an outlet zone being mounted on the housing.

A vehicle combustion noise-masking control method includes: receiving driving information of a vehicle; estimating a frequency of a combustion noise generated in the vehicle using the driving information; and outputting a masking sound when the frequency is equal to or larger than a predetermined frequency.

The technology described herein can be embodied in a computer implemented method that includes detecting, by one or more processing devices, onset of an unstable condition in an active noise control system. The method also includes obtaining, responsive to detecting the onset of the unstable condition, updated filter coefficients for a system-identification filter configured to represent a transfer function of a secondary path of the active noise control system. The updated filter coefficients are generated using a set of multiple subband adaptive filters, wherein filter coefficients of each subband adaptive filter in the set are configured to adapt to changes in a corresponding portion of a frequency range associated with potential unstable conditions in the active noise control system. The method also includes programming the system identification filter with the updated coefficients to affect operation of the active noise control system.

An exhaust system for an internal combustion engine includes a muffler, a first exhaust pipe which is connected to the muffler for sound damping, and a second exhaust pipe which extends in terms of flow in parallel relation to the first exhaust pipe and extends through first muffler in the absence of a flow communication with the first muffler. The first and second exhaust pipes originate from a common exhaust pipe. A switching valve adjusts hereby a throughflow cross section of the second exhaust pipe.

A method of generating a drive signal for a loudspeaker in an exhaust system of an engine of a vehicle or inside or outside a passenger cell includes providing a predetermined source signal for a desired additional sound in a time domain comprising a plurality of signal components of different frequencies; analyzing the source signal based on a phase of the source signal and/or a phase of at least one oscillation in the source signal; identifying a phase of engine noise and/or a phase of at least one oscillation existing in engine noise; shifting the phases of the source signal and/or the oscillation existing in the source signal based on phases identified in engine noise and/or in oscillation existing in engine noise, the relationship of phases of individual oscillations of the source signal among each other being preserved; and generating the drive signal based on the phase-shifted source signal.