SOUND TRANSMITTING SYSTEM FOR A MOTOR VEHICLE AND METHOD FOR A SOUND TRANSMITTING SYSTEM

Abstract

A sound transmitting system for a motor vehicle has a sound generator (2) and a sound-conducting first sound duct (6). The first sound duct (6) has a proximal end (7) connected to the sound generator (2) to transmit sound and a distal end (21) facing away from the proximal end (7) and via which a sound from the generated sound enters a passenger compartment (19) or external region (20) of a bodywork (26) of the motor vehicle (12). To bring about a specific sound characteristic of the resulting sound, a first length (L1) of the first sound duct (6) and/or a first diameter (D1) of the first sound duct (6) and/or a first cross-sectional area (Q1) of the first sound duct (6) are/is adapted as a function of the generated sound.

Claims

1. A sound transmitting system for a motor vehicle, comprising a sound generator and a sound-conducting first sound duct, the first sound duct being configured to transmit a sound generated by the sound generator, and having a proximal end connected to the sound generator to transmit sound and a distal end facing away from the first end so that a generated sound enters a passenger compartment or external region of a bodywork of the motor vehicle, at least one of a first length of the first sound duct, a first diameter of the first sound duct and a first cross-sectional area of the first sound duct being selected as a function of the generated sound to bring about a specific sound characteristic of the resulting sound

2. The sound transmitting system of claim 1, further comprising a second sound duct that has a second length, a second diameter and a second cross-sectional area, the second sound duct having a proximal end connected to the sound generator to transmit sound.

3. The sound transmitting system of claim 2, wherein the sound generator has an adjustable actuator for generating sound.

4. The sound transmitting system of claim 3, wherein the actuator is designed to move a diaphragm of the sound generator.

5. The sound transmitting system of claim 3, wherein the actuator can be activated with the aid of an open-loop and closed-loop control system of the motor vehicle.

6. The sound transmitting system of claim 5, wherein the open-loop and closed-loop control system is connected to a bus.

7. The sound transmitting system of claim 5, further comprising a measuring element connected to the open-loop and closed-loop control system to absorb oscillations of an intake section and/or of an exhaust tract of a drive assembly of the motor vehicle.

8. The sound transmitting system of claim 5, further comprising a characteristic diagram formed in the open-loop and closed-loop control system to activate the actuator.

9. The sound transmitting system of claim, 5 wherein the sound duct is formed from a plastic.

10. The sound transmitting system of claim 1, wherein the distal end of the sound duct opens into a passenger cell of the motor vehicle.

11. The sound transmitting system of claim 1, wherein the distal end of the sound duct opens into an external region.

12. The sound transmitting system of claim 3, wherein the sound generator is manufactured from a plastic.

13. A method for a sound transmitting system, the method using a sound generator and a sound-conducting first sound duct, the first sound duct being designed to transmit a sound generated by the sound generator, and the first sound duct having a proximal end connected to the sound generator to transmit sound and a distal end facing away from the proximal end and via which a sound that results from the generated sound enters a passenger compartment or external region of a bodywork of the motor vehicle (12), the method comprising adapting a first length of the first sound duct and/or a first diameter of the first sound duct and/or a first cross-sectional area of the first sound duct to achieve a specified noise.

14. The method of claim 13, wherein a second sound duct with a second length, a second diameter and a second cross-sectional area connected at its proximal end to the sound generator to transmit sound, and wherein the method further comprises adapting the second length and/or the second diameter and/or the second cross section.

15. The method of claim 14, wherein the sound generator is connected to an open-loop and closed-loop control system of the motor vehicle, and wherein the method further comprising using data of the open-loop and closed-loop control system to generate sound.

Description

BRIEF DESCRIPTION

[0034] FIG. 1 shows a schematic illustration of a sound transmitting system according to the invention in a first exemplary embodiment.

[0035] FIG. 2 shows a schematic illustration of the sound transmitting system according to the invention in a second exemplary embodiment.

[0036] FIG. 3 shows a schematic illustration of the sound transmitting system according to FIG. 2 in a motor vehicle.

DETAILED DESCRIPTION

[0037] A sound transmitting system according to a first embodiment of the invention is identified by the numeral 1 in FIG. 1. The sound transmitting system 1 has a sound generator 2 with a housing 3 and a diaphragm 4 held in the housing 3. The sound transmitting system 1 also has an actuator 5 that excites the diaphragm 4 and causes the diaphragm to oscillate. The diaphragm 4 is circular and the entire circumference is secured in the housing 3. The diaphragm 4 could have other shapes, for example ellipsoidal or polygonal. An outer contour of the diaphragm 4 and an inner contour of the housing 3 are preferably have complementary shapes in the region in which the diaphragm 4 is held.

[0038] Sound waves, air pressure waves or air pressure oscillations are generated in the housing 3 when the diaphragm 4 oscillates. The housing 3 is connected to a first sound duct 6 to transmit the sound waves in a sound-conducting fashion. The first sound duct 6 is a tube and the sound waves are transmitted both in the form of a solid-borne sound and in the form of an air-borne sound through the tube 6.

[0039] The first sound duct 6 has a proximal end 7 connected in a sound-conducting fashion to the housing 3, and also has a first length L1, a first diameter D1 and a first cross-sectional area Q1.

[0040] FIG. 2 illustrates a second embodiment of the sound transmitting system 1 of the invention. The sound transmitting system 1 of FIG. 2 has first and second sound ducts 6 and 8. The second sound duct 8 has a proximal end 9 connected in a sound-conducting fashion to the housing 3. The second sound duct 8 has a second length L2, a second diameter D2 and a second cross-sectional area Q2.

[0041] It is not absolutely necessary for the first sound duct 6 and the second sound duct 8 to be held coaxially on the housing 3, as illustrated in FIG. 2. Likewise, it is not absolutely necessary for the first and second sound ducts 6 and 8 to be held on oppositely facing sides 10 and 11 of the housing 3. Rather, both sound ducts 6 and 8 could be held on the side 10 or on the further side 11.

[0042] FIG. 3 illustrates the sound transmitting system 1 of FIG. 2 installed in a motor vehicle 12. The motor vehicle 12 has a drive assembly 13 in the form of a 4-cylinder internal combustion engine. The internal combustion engine is connected in a signal-transmitting fashion to an open-loop and closed-loop control system 14 of the motor vehicle 12. The transmission of signals takes place in both directions here. Thus, signals for operating the internal combustion engine 13 are transmitted from the open-loop and closed-loop control system 14 to the internal combustion engine 13 and measurement signals are transmitted from the internal combustion engine 13 to the open-loop and closed-loop control system 14, for example signals of measured pressures and/or temperatures and/or mass flow rates. The open-loop and closed-loop control system 14 preferably has a CAN bus or a FlexRay bus 15.

[0043] In the illustrated embodiment, the sound transmitting system 1 is arranged in a front region 16 of the motor vehicle 12, but could be arranged in a rear region 17 of the motor vehicle 12 or in a central region 18 of the motor vehicle 12. Transmission of sound by the sound transmitting system 1 can take place with the aid of the sound ducts 6, 8 into a passenger compartment or cell 19 and/or into an external region 20.

[0044] In the embodiment of FIG. 3, sound is transmitted into the passenger cell 19. More particularly, the first and second sound ducts 6 and 8 have distal ends 21 and 22 respectively that face away from the respective proximal ends 7 and 9. The distal ends 21 and 22 are connected to a bodywork 26 of the motor vehicle 12 and lead into the passenger cell 19 and lead into the passenger cell 19. Thus, air pressure oscillations generated by the diaphragm 4 with the aid of the actuator 5 are transmitted into the passenger cell 19.

[0045] The first and second sound ducts 6 and 8 are connected independently of one another to the bodywork 26. Additionally, the first and second sound ducts 6 and 8 have cross-sectional areas Q1, Q2 that are identical or congruent. Likewise, the diameters D1, D2 of the sound ducts 6, 8 are identical. The first length L1 of the first sound duct 6 is longer than the second length L2 of the second sound duct 8 to bring about a harmonic sound in the passenger cell 19.

[0046] In an alternate embodiment, the lengths L1, L2 and the diameters D1, D2 are identical, but the cross-sectional areas Q1, Q2 are not congruent, so that harmonic chords are brought about.

[0047] The first and second sound ducts 6 and 8 are connected in a sound-conducting fashion at different locations to the bodywork 26. For example, the first and second sound ducts 6 and 8 may be held at an A pillar of the bodywork 26 with the aid of a plug-type connection.

[0048] If the distal ends 21 and/or 22 lead into the external region 20, the air pressure oscillations are transmitted to the external region 20.

[0049] The air oscillations or the resulting sound at the distal ends 21, 22 of the sound ducts 6, 8 are a result of the sound originally generated by the sound generator 2 and/or the air oscillations generated by the sound generator 2 and the changes in the sound or air oscillations as a function of the lengths L1, L2, the diameter D1, D2 and the shapes of the cross-sectional areas Q1, Q2. The resulting sound therefore is dependent on the geometric variables L1, L2, D1, D2, Q1, Q2.

[0050] The resulting sound also is dependent on the selected material of the sound ducts 6, 8 and their processing. The air pressure waves running through the sound ducts 6, 8 experience a different friction at a rough inner surface of the tube-like sound ducts 6, 8 than at a smooth inner surface. In other words, the resulting sound also is dependent on a surface roughness of the inner surfaces of the sound ducts 6, 8.

[0051] The solid-borne sound also is a portion of the resulting sound in addition to the air-borne sound or the air oscillations running through the sound ducts, and therefore the material of the sound ducts 6, 8 must be taken into account. Thus, sound of a sound duct 6, 8 made from plastic is different from a sound duct 6, 8 made from metal.

[0052] The actuator 5 can be adjusted and is activated by the open-loop and closed-loop control system 14, i.e. the diaphragm 4 is excited to generate the oscillation. The activation by the open-loop and closed-loop control system 14 can take place in different ways.

[0053] In one case, current driving state variables such as, for example, speed, engine rotation speed, engine load are input variables for activating the actuator 5. In this context, the correspondingly selected driving state variables are transmitted to the open-loop and closed-loop control system 14 by the bus 15 to pick up current measurement data. The actuator 5 is activated by the open-loop and closed-loop control system 14 as a function of these driving state variables. That is to say, in other words, the actuator 5 excites the diaphragm 4 as a function of the driving state variables that are used. Therefore, in the case of a high engine rotation speed, the diaphragm 4 is excited to high frequencies by the actuator 5.

[0054] In a subsequent case, a characteristic diagram can be stored in the open-loop and closed-loop control system 14 to operate the actuator 5. This characteristic diagram can be embodied in a multi-dimensional fashion. The operation of the actuator 5 therefore is carried out as a function of predetermined driving state variables that are determined during the operation of the motor vehicle 12. These driving state variables are processed in the open-loop and closed-loop control system 14, and a corresponding operating point of the actuator 5 is selected in the characteristic diagram of the actuator 5 in accordance with the driving state.

[0055] In a further case, the actuator 5 is operated as a function of a current oscillation in an intake section 23 of the drive assembly 13 and/or of an exhaust tract, for example of an intake duct of the intake section 23 or an exhaust gas duct of the exhaust tract. These oscillations are registered by measurement elements. The associated measurement data is transmitted to the open-loop and closed-loop control system 14, which then activates the actuator 5. In this possibility, the open-loop and closed-loop control system 14 can be used to influence the previously determined measurement signal. For example, in the case of a low amplitude of the current oscillation, the amplitude can be increased or reduced with the aid of the open-loop and closed-loop control system 14 before the activation of the actuator 5.

[0056] The internal combustion engine 13 comprises a first cylinder bank 24 and a second cylinder bank 25. The first and second cylinder banks 24 and 25 have a multiplicity of cylinders, comprising inlet ducts and outlet ducts. The ducts are opened and closed by a working cycle using inlet valves and outlet valves. On the inlet side, these inlet ducts are connected to the intake section 23 so that they can be flowed through. The intake section 23 comprises an air filter and a charge air cooler.

[0057] On the exhaust side, the outlet ducts are connected to the exhaust tract of the internal combustion engine 13, via which exhaust tract fuel mixture that is burnt in the cylinders can flow into the surroundings. This exhaust tract usually comprises a silencer in addition to an emission reduction unit such as a particle filter or a catalytic converter. During the operation of the internal combustion engine 13, a sound that is characteristic of this internal combustion engine 13 is brought about, inter alia, by a corresponding configuration of the intake section 23 and the exhaust tract.