METHOD AND DEVICE FOR SUPPRESSING ACOUSTIC DISTURBANCE SIGNALS RESULTING FROM THE OPERATION OF A MOTOR VEHICLE-SIDE ENGINE UNIT

Description

[0001] The invention relates to a method for suppressing acoustic interference signals resulting from the operation of a motor vehicle drive unit and introduced into a passenger compartment of the motor vehicle by means of at least one artificially generated acoustic counter-signal defined by at least one counter-signal parameter.

[0002] Corresponding methods are known in principle from the field of automotive audio technology under the name "Engine Order Cancellation." The objective of such methods is always the most complete possible suppression of acoustic interference signals resulting from the operation of a vehicle's drive unit and introduced into the passenger compartment. These interference signals can be, for example, vibrations. The principle of such methods typically relies on detecting an acoustic interference signal using suitable sensors and, based on the detected acoustic interference signal, artificially generating a counter-signal and introducing it into the passenger compartment via a suitable output device.The acoustic counter-signal, particularly due to a phase opposite to that of the acoustic interference signal, causes a, if necessary complete, suppression of the acoustic interference signal.

[0003] The suppression of corresponding acoustic interference signals using appropriate methods is sometimes significantly dependent on the physical conditions prevailing in the passenger compartment. These conditions can, for example, substantially influence the speed of sound propagation, which can negatively affect the detection of acoustic interference signals or the generation of counter-signals, and therefore result in suboptimal suppression of the acoustic interference signals.

[0004] DE 42 36 155 A1 discloses a method for reducing interior noise in vehicles.

[0005] The invention is based on the objective of providing an improved method, in particular with regard to the suppression of acoustic interference signals under different physical conditions in a passenger compartment, for suppressing acoustic interference signals resulting from the operation of a motor vehicle drive unit and introduced into a passenger compartment of the motor vehicle by means of at least one artificially generated acoustic counter-signal defined by at least one counter-signal parameter.

[0006] The problem is solved by a method according to claim 1. The dependent claims relate to possible embodiments of the method. The problem is further solved by a device according to claim 3. The dependent claims relate to possible embodiments of the device. Likewise, a motor vehicle according to claim 5 solves the problem.

[0007] The invention is defined by the subject matter of the appended claims. The method described herein serves to suppress acoustic interference signals, i.e., in particular vibrations, resulting from the operation of a motor vehicle's drive unit and introduced into the passenger compartment of the motor vehicle, by means of at least one artificially generated acoustic counter-signal defined by at least one counter-signal parameter. The method thus enables the acoustic suppression or damping of corresponding acoustic interference signals, hereinafter referred to as interference signals, by generating artificial acoustic counter-signals, hereinafter referred to as counter-signals. In principle, within the framework of the method, interference signals are detected by means of suitable sensors, and counter-signals are artificially generated based on the detected interference signals and output into the passenger compartment.The counter-signals, particularly due to a phase opposite to that of the respective interference signals, cause a, if necessary complete, suppression of the interference signals.

[0008] The procedure comprises the following steps, which are explained in more detail below: In the first step of the procedure, at least one physical quantity, which of course also includes a value or range of values ​​of a specific physical quantity, i.e., a pressure, humidity, or temperature value, is recorded in the passenger compartment of the motor vehicle. The physical quantity can be the pressure, humidity, or temperature in or within the passenger compartment. Several (different) physical quantities are recorded. In all cases, the recording of the respective physical quantities enables a more or less complete picture of the physical, and possibly climatic, conditions in the passenger compartment, depending on the number of physical quantities recorded.The respective physical quantities are measured by means of a suitable vehicle-mounted measuring device, which is equipped with suitable measuring elements, particularly those located or designed within the passenger compartment, with regard to the physical quantities to be measured. These measuring elements can be, for example, pressure, humidity, or temperature sensors.

[0009] In a second step of the process, data describing at least one recorded physical quantity in the passenger compartment of the motor vehicle is generated. The recorded physical quantity(ies) or values ​​are thus represented in data that can be further processed. This data can be generated within the data acquisition device itself.

[0010] In a third step of the process, depending on the physical quantity(ies) described by the acquisition information, at least one acoustic counter-signal parameter influencing the counter-signal is selected. Hereinafter referred to simply as a counter-signal parameter. The selection is made from a storage device containing multiple counter-signal parameters. Each counter-signal parameter is associated with a specific physical quantity, value, or range of values; thus, each counter-signal parameter is specifically linked to a particular physical quantity, value, or range of values.The selection of a suitable counter-signal parameter is based on the physical quantity described by the acquisition information, whereby a counter-signal parameter whose assigned physical quantity corresponds to the physical quantity described by the acquisition information is selected. Suitable selection algorithms can be used for this purpose. The storage device can be configured as a look-up table in this respect. The assignment of respective counter-signal parameters to respective physical quantities can be based on assignment criteria derived from corresponding preliminary investigations in which the influence of different physical parameters in the passenger compartment on the suppression of corresponding interference signals in the passenger compartment was examined. Specifically, transfer functions, for example, can be used as examples of corresponding counter-signal parameters.The data were measured for different temperatures and then linked to the respective temperature and stored in the storage device.

[0011] Alternatively or additionally, in the third step of the procedure, at least one counter-signal parameter influencing the counter-signal, in particular a pre-selected parameter, is adjusted or changed depending on the physical quantity described by the acquisition information. The adjustment of the counter-signal parameter, in particular a pre-selected parameter, can be carried out by means of an adjustment function or rule selected depending on the physical quantity described by the acquisition information, i.e., generally an adjustment algorithm. The adjustment function can, for example, include an interpolation or an extrapolation of a respective counter-signal parameter with respect to a specific target quantity.The selection of an adaptation function, depending on the physical quantity described by the acquisition information, is made from a memory device containing multiple adaptation functions, which in turn contains multiple adaptation functions or in which multiple counter-signal parameters are stored as data. The memory device stores at least one adaptation function, each associated with a specific physical quantity, value, or range of values; thus, each adaptation function is specifically linked to a particular physical quantity, value, or range of values. The selection of a corresponding adaptation function is based on the physical quantity described by the acquisition information, whereby an adaptation function whose associated physical quantity or value is specified is selected.The value corresponding to the physical quantity described by the acquisition information is selected. Suitable selection algorithms can be used for this purpose. The storage device can therefore be configured as a lookup table. The assignment of respective adaptation functions to respective physical quantities can be based on assignment criteria derived from preliminary investigations that examined the influence of different physical parameters in the passenger compartment on the suppression of corresponding interference signals.

[0012] EOC parameters or EOC tuning parameters, namely λ (forgetting factor) or µ (step size), are also adjusted via an adjustment function. In other words, EOC parameters or EOC tuning parameters can be adjusted by means of an adjustment function selected based on the physical quantity described by the acquisition information. The EOC parameters or EOC tuning parameters influence corresponding counter-signal parameters; therefore, adjusting EOC parameters or EOC tuning parameters can also adjust counter-signal parameters.

[0013] In all cases, the corresponding counter-signal parameter can be, for example, the phase or frequency of the counter-signal, a transfer function (also known as a "transfer path") describing the phase and frequency of the counter-signal, or the intensity of the counter-signal. Thus, the phase or frequency of the counter-signal, a transfer function describing the phase and frequency of the counter-signal (which typically relates to a specific spatial arrangement of sensors for detecting a corresponding interference signal relative to an output device for outputting a corresponding counter-signal, or vice versa), or the intensity of the counter-signal can be used. In the third step of the process, a corresponding transfer function can therefore be selected or adapted depending on the physical quantity described by the detection information.

[0014] In a fourth step of the process, a counter-signal is generated based on at least one selected counter-signal parameter and / or on at least one adapted counter-signal parameter. The generation of the counter-signal and its acoustic properties are thus based, on the one hand, on the interference signal to be suppressed and, on the other hand – due to a corresponding selection or adaptation of at least one counter-signal parameter – on the physical conditions in the passenger compartment, which are at least partially represented by the respective physical quantities measured.

[0015] In a fifth step of the process, the generated counter-signal is output into the passenger compartment of the motor vehicle to suppress interference signals resulting from the operation of the vehicle's drive unit and introduced into the passenger compartment. The output is provided by a suitable output device, in particular one located or integrated within the passenger compartment. The output device may, for example, be a loudspeaker or at least include one.

[0016] Overall, this provides an improved method, particularly with regard to the suppression of acoustic interference signals under different physical conditions in a passenger compartment, for suppressing interference signals resulting from the operation of a motor vehicle drive unit and introduced into a passenger compartment of the motor vehicle by means of at least one artificially generated counter-signal defined by at least one counter-signal parameter.

[0017] The procedure involves recording the time-dependent progression of at least one physical quantity over a specific period, e.g., 10, 30, or 60 seconds. This allows for the detection of any (temporal) changes in the physical quantity or physical conditions within the passenger compartment and their inclusion in the selection or adjustment of the respective counter-signal parameters.

[0018] Similarly, at least one physical quantity is recorded continuously or discontinuously, i.e., at certain regular or irregular (time) intervals.

[0019] As mentioned at the beginning, a counter-signal can be defined by several counter-signal parameters. When selecting at least one counter-signal parameter that influences the counter-signal, all counter-signal parameters that influence it are selected, resulting in a completely new counter-signal. Alternatively or additionally, when adjusting at least one counter-signal parameter that influences the counter-signal, all counter-signal parameters that influence it are adjusted, resulting in a completely new counter-signal.

[0020] In addition to the method, the invention also relates to a device for suppressing interference signals resulting from the operation of a motor vehicle drive unit and introduced into a passenger compartment of the motor vehicle by means of at least one artificially generated counter-signal defined by at least one counter-signal parameter, in particular according to a method as described above.

[0021] The device comprises, in particular, a detection device, a control device, a storage device, and an output device. The detection device is configured to detect at least one physical quantity, i.e., pressure, humidity, or temperature, in the passenger compartment of a motor vehicle. The control device is configured to generate at least one detection information describing the at least one detected physical quantity in the passenger compartment of the motor vehicle and to select at least one counter-signal parameter influencing the counter-signal from the storage device, depending on the physical quantity described by the detection information, and / or to adjust at least one counter-signal parameter influencing the acoustic counter-signal, i.e.,The phase or frequency of the counter-signal, or a transfer function describing the phase and frequency of the counter-signal, or the intensity of the counter-signal, is determined based on the physical quantity described by the acquisition information from a storage device and is configured to generate a counter-signal based on at least one selected counter-signal parameter and / or based on at least one adapted counter-signal parameter. The output device is configured to output the generated counter-signal into the passenger compartment of the motor vehicle to suppress interference signals resulting from the operation of the vehicle's drive unit and introduced into the passenger compartment.

[0022] In principle, all statements relating to the method apply analogously to the device. Therefore, the device can be further developed as follows: The storage device can contain several acoustic counter-signal parameters. At least one acoustic counter-signal parameter, each assigned to a specific physical quantity, can be stored in the storage device.

[0023] The control unit can be configured to adjust the acoustic counter-signal parameter, in particular the pre-selected one, by means of an adjustment function selected depending on the physical quantity described by the detection information.

[0024] The storage device can contain multiple adaptation functions. Within the storage device, at least one adaptation function, each associated with a specific physical quantity, can be stored as data.

[0025] The recording device can be configured to record a time-dependent progression of at least one physical quantity over a specific period of time.

[0026] The recording device may also be configured to continuously or discontinuously record at least one physical quantity.

[0027] The control device is configured to select all counter-signal parameters influencing the counter-signal parameter when selecting at least one counter-signal parameter, so that a completely new counter-signal is selected, and / or to adjust all counter-signal parameters influencing the counter-signal parameter when adjusting at least one counter-signal parameter, so that a complete counter-signal is adjusted.

[0028] The invention further relates to a motor vehicle, i.e., in particular a passenger car. The motor vehicle comprises at least one drive unit, i.e., in particular an electric and / or an internal combustion engine, wherein acoustic interference signals are introduced into a passenger compartment of the motor vehicle as a result of the operation of the drive unit. To suppress the interference signals, the motor vehicle comprises a device as described. Therefore, all descriptions relating to the device and the method also apply analogously to the motor vehicle.

[0029] The invention is explained in more detail with reference to an exemplary embodiment shown in the drawing figures. The single figure shows a schematic representation of a device according to one exemplary embodiment.

[0030] The device 1 shown in the figure is arranged or configured in a purely schematically indicated motor vehicle 2 and is designed to suppress interference signals 5, i.e., in particular vibrations, resulting from the operation of the vehicle's drive unit 3, i.e., typically an electric and / or an internal combustion engine, which are introduced into the passenger compartment 4 of the motor vehicle 2, by means of at least one artificially generated counter-signal 6 defined by at least one counter-signal parameter. The device 1 can detect corresponding interference signals 5 and, based on the detected interference signals 5, artificially generate counter-signals 6 and output them into the passenger compartment 4. For this purpose, the device 1 comprises as functional components a sensor 7, e.g., in the form of one or more microphone devices, for detecting corresponding interference signals 5, and an output device 8, e.g.,in the form of one or more loudspeaker devices, for outputting corresponding counter-signals 6 into the passenger compartment 4. The sensor system 7 and the output device 8 are (data-wise) connected to a central hardware and / or software-implemented control unit 9 as a further functional component of the device 1.

[0031] Further functional components of the device 1 are a detection device 10 and a storage device 11. The detection device 10 and the storage device 11 are also (data-wise) connected to the control device 9. The detection device 10 is configured to detect at least one physical quantity, i.e., pressure, humidity, or temperature, in the passenger compartment 4 and includes suitable detection elements (not shown), i.e., pressure, humidity, or temperature sensors. The storage device 11, optionally configured as a lookup table, is configured to store data or information and includes suitable data storage elements (not shown).

[0032] By means of the device 1, or rather through the interaction of the described functional components of the device 1, a method for suppressing (damping) interference signals 5 resulting from the operation of the drive unit 3 and introduced into the passenger compartment 4 can be implemented by means of artificially generated counter-signals 6 defined by at least one counter-signal parameter. The method thus enables the acoustic suppression or damping of corresponding interference signals 5 by the targeted generation of artificial counter-signals 6. The counter-signals 6, in particular due to a phase opposite to that of the respective interference signals 5, cause a suppression of the interference signals 5, possibly complete.

[0033] In a first step of the procedure, at least one physical quantity, which of course includes a value or range of values ​​of the respective specific physical quantity, i.e., a pressure, humidity, or temperature value, is recorded in passenger compartment 4 by means of the recording device 10. As mentioned, the physical quantity can be the pressure, humidity, or temperature in or within passenger compartment 4. The recording of the respective physical quantities enables a more or less complete representation of the physical, and possibly climatic, conditions in passenger compartment 4, depending on the number of physical quantities recorded. The recording of the physical quantity(ies) is continuous or discontinuous, encompassing a time-dependent progression of a physical quantity over a specific period.

[0034] In a second step of the process, for example by means of the acquisition device 10, acquisition information describing at least one acquired physical quantity is generated. The physical quantity(ies) or values ​​acquired by means of the acquisition device 10 are thus represented in acquisition information that can be processed (further) as data.

[0035] In a third step of the procedure, depending on the physical quantity(ies) described by the acquisition information, at least one counter-signal parameter influencing the counter-signal 6 is selected from the storage device 11. Several counter-signal parameters are stored in the storage device 11 for this purpose. Each counter-signal parameter is stored linked to a specific physical quantity or a specific value or range of values ​​of a specific physical quantity. Thus, each counter-signal parameter is assigned a specific physical quantity or a specific value or range of values ​​of a specific physical quantity. The selection of a corresponding counter-signal parameter is based on the physical quantity described by the acquisition information, whereby a counter-signal parameter, its assigned physical quantity, or a specific value or range of values ​​of a specific physical quantity, is selected.The assigned value of the physical quantity described by the acquisition information is selected. Suitable selection algorithms can be used for this purpose. The assignment of respective counter-signal parameters to respective physical quantities can be carried out on the basis of assignment criteria obtained from preliminary investigations in which the influence of different physical parameters on the suppression of corresponding interference signals 5 in the passenger compartment 4 was examined.

[0036] EOC parameters or EOC tuning parameters, such as λ (forgetting factor) or µ (step size), are also adjusted via an adjustment function. In other words, EOC parameters or EOC tuning parameters can be adjusted by means of an adjustment function selected based on the physical quantity described by the acquisition information. The EOC parameters or EOC tuning parameters influence corresponding counter-signal parameters; therefore, adjusting EOC parameters or EOC tuning parameters can also adjust counter-signal parameters.

[0037] Alternatively or additionally, in the third step of the procedure, at least one counter-signal parameter influencing the counter-signal 6, in particular a pre-selected one, is adjusted or changed depending on the physical quantity described by the acquisition information. The adjustment of the counter-signal parameter is carried out by means of an adjustment function or rule selected depending on the physical quantity described by the acquisition information, i.e., generally an adjustment algorithm. The adjustment function can, for example, include an interpolation or an extrapolation of a respective counter-signal parameter with respect to a specific target quantity. The selection of an adjustment function depends on the physical quantity described by the acquisition information. Several counter-signal parameters are stored in the storage device 11 for this purpose.Each adaptation function is stored in relation to a specific physical quantity, value, or range of values. Thus, each adaptation function is assigned a specific physical quantity, value, or range of values. The selection of a suitable adaptation function is based on the physical quantity described by the acquisition information, whereby an adaptation function whose assigned physical quantity or value corresponds to the physical quantity described by the acquisition information is selected. Suitable selection algorithms can be used for this purpose.The assignment of respective adaptation functions to respective physical quantities can in turn be carried out on the basis of assignment criteria obtained from corresponding preliminary investigations in which the influence of different physical parameters on the suppression of corresponding disturbance signals in passenger compartment 4 was investigated.

[0038] The corresponding counter-signal parameters can be, for example, the phase of the counter-signal 6, the frequency of the counter-signal 6, a transfer function describing the phase and frequency of the counter-signal 6, or the intensity of the counter-signal 6. The transfer function typically refers to the specific spatial arrangement of the sensor 7 for detecting a corresponding interference signal 5 relative to the output device 8 for outputting a corresponding counter-signal 6, as indicated by the double arrow in the figure.

[0039] In a fourth step of the procedure, the control unit 9 generates the counter-signal 6 based on the selected counter-signal parameter and / or on the basis of the adjusted counter-signal parameter. The generation of the counter-signal 6 and its acoustic properties are therefore based, on the one hand, on the interference signal 5 to be suppressed and, on the other hand, on the physical conditions in the passenger compartment 4 represented by the respective detected physical quantities.

[0040] In a fifth step of the process, the generated counter-signal 6 is output to the passenger compartment 4 via the output device 8 to suppress corresponding interference signals 5. As mentioned, the counter-signal 6 typically has a phase opposite to that of the interference signal 5 to be suppressed.

[0041] When selecting the counter-signal parameter, all parameters influencing counter-signal 6 can, of course, be selected, thus creating a completely new counter-signal 6. Similarly, when adjusting the counter-signal parameter, all parameters influencing counter-signal 6 can be adjusted, thus creating a completely new counter-signal 6.

Claims

1. Method for suppressing acoustic interference signals (5) resulting from the operation of a motor vehicle-side drive unit (3), introduced into a passenger cell (4) of the motor vehicle (2) by means of at least one artificially generated, defined by at least one counter signal parameter, acoustic counter signal (6), comprising the following steps: - detecting at least one physical quantity in the passenger compartment (4) of the motor vehicle (2), - Generate at least one the at least one detected physical quantity in the passenger cell (4) of the motor vehicle (2) descriptive detection information, - selecting at least one counter signal parameter affecting the acoustic counter signal (6) as a function of the physical quantity described by the detection information, or - adjusting at least one counter signal parameter affecting the acoustic counter signal (6) as a function of the physical quantity described by the detection information, - generating an acoustic counter signal (6) based on at least one selected or adapted counter signal parameter, and - Output of the generated acoustic counter signal (6) into the passenger cell (4) of the motor vehicle (2) for suppression of acoustic interference signals (5) resulting from the operation of the motor vehicle-side drive unit (3) introduced into the passenger cell (4) of the motor vehicle (2), wherein the selection of an acoustic counter-signal parameter in dependence of the physical size described by the detection information from a plurality of acoustic counter-signal parameters comprising memory device (11) is carried out, wherein in the memory device (11) each at least a certain physical size associated acoustic counter-signal parameters are stored in terms of data, wherein the adaptation of the, in particular preselected, acoustic counter-signal parameter by means of a selected in dependence of the physical size described by the detection information adaptation function, wherein the selection of an adaptation function in dependence of the physical size described by the detection information from a plurality of adaptation functions comprising memory device (11) is carried out, wherein in the memory device (11) at least a certain physical size associated adaptation functions are stored in terms of data, wherein in the context of selecting at least one of the acoustic counter signal (6) influencing counter signal parameters all the acoustic counter signal (6) influencing counter signal parameters are selected, so that a completely new acoustic counter signal (6) is selected, and / or, wherein, in the context of adjusting at least one of the audible counter signal (6) affecting counter signal parameters, all the audible counter signal (6) affecting counter signal parameters are adjusted so that a complete audible counter signal (6) is adapted, wherein a time-dependent course of at least one physical quantity is detected over a certain period of time, wherein which is continuously or discontinuously recorded at least one physical quantity, characterized in that as engine order cancellation parameters, EOC parameters, the pressure, humidity or temperature within the passenger cell (4) of the motor vehicle is detected, wherein several different physical quantities are detected, where an adjustment function also adjusts a forget factor or increment as an EOC parameter.

2. The method of claim 1, characterized in that as the at least one parameter affecting the acoustic counter signal (6) the phase of the acoustic counter signal (6) or the frequency of the acoustic counter signal (6) or a transfer function describing the phase and frequency of the acoustic counter signal (6) or the intensity of the acoustic counter signal (6) is used.

3. Device (1) for suppressing acoustic interference signals (5) resulting from the operation of a motor vehicle-side drive unit (3), introduced into a passenger cell (4) of the motor vehicle (2) by means of at least one artificially generated, defined by at least one counter signal parameter, acoustic counter signal (6) according to the method according to one of the preceding claims, comprising a detection device (10), a control device (9), a storage device (11) and an output device (8), wherein the detection device (10) is set up for detecting at least one physical quantity in the passenger compartment (4) of a motor vehicle (2), the control device (9) for generating at least one of the at least one detected physical quantity in the passenger cell (4) of the motor vehicle (2) descriptive detection information and for selecting at least one affecting the acoustic counter signal (6) counter signal parameter in dependence of the physical quantity described by the detection information from the storage device (11) or for adjusting at least one of the acoustic counter signal (6) affecting the counter signal parameter as a function of the physical size described by the detection information from a memory device (11) and for generation of an acoustic counter signal (6) on the basis of at least one selected or adapted counter signal parameter is set up, and the output device (8) for outputting the generated acoustic counter signal (6) into the passenger cell (4) of the motor vehicle (2) for suppression of the resulting from the operation of the motor vehicle side drive unit (3), introduced into the passenger cell (4) of the motor vehicle (2) acoustic interference signals (5) is set up, wherein the control device (11) comprises several acoustic counter signal parameters, wherein in the storage device (11) each at least a certain physical size associated acoustic counter signal parameters are stored data-wise, wherein the control device (11) is set up to perform the adaptation of the, in particular preselected, acoustic counter signal parameter by means of an adaptation function selected according to the physical size described by the detection information, wherein the storage device (11) comprises several adaptation functions, wherein in the storage device (11) each at least a certain physical size associated adaptation functions are stored data-wise, wherein the control device (9) is configured to select all the counter signal parameters affecting the audible counter signal (6) within the scope of selecting at least one counter signal parameter affecting the audible counter signal (6), so that a completely new audible counter signal (6) is selected and / or, within the scope of adjusting at least one counter signal parameter affecting the audible counter signal (6), to adapt all the counter signal parameters affecting the audible counter signal (6), so that a complete audible counter signal (6) is adapted, wherein the detection device (10) is set up to detect a time-dependent course of at least one physical quantity over a certain period of time, wherein the detection device (10) is configured to detect at least one physical quantity continuously or discontinuously, wherein the detection device (10) is set up to detect the pressure, humidity or temperature within the passenger compartment (4) of the motor vehicle, and wherein the detection device (10) is set up to detect several different physical quantities, characterized in that the control device (9) is set up as engine order cancellation parameter, EOC parameter, via an adjustment function also a forgetting factor or an increment to adjust.

4. Device according to claim 3, characterized in that the at least one parameter affecting the acoustic counter signal (6) is the phase of the acoustic counter signal (6) or the frequency of the acoustic counter signal (6) or a transfer function describing the phase and frequency of the acoustic counter signal (6) or the intensity of the acoustic counter signal (6).

5. Motor vehicle (2), comprising a passenger cell (4) and at least one drive unit (3), wherein the operation of at least one drive unit (3) results in interference noises which are introduced into the passenger cell (4), further comprising an apparatus (1) for suppressing acoustic interference signals (5) resulting from the operation of the drive unit (3) introduced into the passenger cell (4) by means of at least one artificially generated, defined by at least one counter signal parameter, acoustic counter signal (6) according to claim 3 or 4.