The present invention relates generally to a sound generator for a vehicle and, more particularly, to a sound generator for modulation of sound in the engine compartment of the vehicle and the vehicle interior.
An internal combustion engine in a vehicle typically is in fluid communication with an air induction system and an air exhaust system for providing air to the engine, and exhausting air from the engine, respectively. In the internal combustion engine, sound energy is often generated in the form of acoustic pressure waves as air flows through the air induction and exhaust systems. In particular, vibrations are often caused by intake air flowing through an air feed conduit of the air induction system. Specifically, vibrations are caused by the induction of air into a cylinder of the internal combustion engine by a cyclic movement of a piston slidably disposed in the cylinder.
Oftentimes in vehicles, such as luxury vehicles, for example, sound energy generation by the air induction is desirably minimized. Resonators have been employed to reduce engine intake noise and improve noise comfort in the vehicle interior. Resonators operate by reflecting sound waves generated by the engine 180 degrees out of phase. The combination of the sound waves generated by the engine with the out of phase sound waves results in a reduction or cancellation of the amplitude of the sound waves. Such resonators typically include a single, fixed volume chamber for dissipating the intake noise. Multiple resonators are also frequently used to attenuate several sound waves of different frequencies.
Many vehicles also use interior sound quality to differentiate from competition. For example, in high performance vehicles and sports cars, the transmission of sound energy to the vehicle interior may provide for a more aesthetically intensive driving experience. The air induction system of a turbo-charged engine, however, is known to generate less sound energy than the induction system of a normally-aspirated engine. Additionally, the air induction system in many vehicles is disposed in a location that does not permit a desired amount of sound to reach the vehicle interior. Thus, devices have been employed to transmit sound energy generated by high pressure areas in the induction system to the engine compartment or the vehicle interior. The sound quality in the vehicle interior may thereby be modulated to provide an aesthetically desirable sound quality.
A known device for generating sound in vehicles has included, for example, a hollow body separated into at least two chambers by a sound transmitting device. The device has sometimes included an output conduit section for transmission of sound to the vehicle interior. Sound generation devices of the art also have employed a spring mass system, such as an oscillating bellows, that typically has a single resonant frequency.
A device for the targeted transmission of sound from an induction tract of an internal combustion engine into the interior of the motor vehicle is disclosed in U.S. Pat. No. 6,600,408. The device includes a hollow transmission body that communicates with the induction tract on the intake side and emits sound on the output side of the vehicle interior. U.S. Pat. No. 6,644,436 discloses a device for noise configuration in a motor vehicle that has a hollow body which is divided into at least two spaces. Further, U.S. Pat. No. 6,848,410 discloses a device for targeted sound transmission from an intake tract that has several resonator chambers operating in parallel.
There is a continuing need for a sound generator that may be used to selectively modulate sound quality in the engine compartment or the vehicle interior. Desirably, the sound generator is readily configurable to meet various tuning requirements. It is also desirable that a structural complexity of the sound generator is minimized.
In accordance with the instant disclosure, a sound generator that is able to modulate sound quality in the engine compartment of the vehicle interior, is readily configurable to meet tuning requirements, wherein a structural complexity thereof is minimized, has surprisingly been discovered.
In one embodiment, a sound generator for a vehicle comprises a hollow drum having an outer wall with an aperture formed therein, the drum adapted to be coupled to and in fluid communication with an air conduit; and a sound radiation panel at least partially covering the aperture and adapted to radiate sound energy to at least one of an engine compartment and an interior of the vehicle.
In another embodiment, a vehicle system for modulating sound in at least one of an engine compartment and a vehicle interior comprises an internal combustion engine disposed in the engine compartment; an air conduit in fluid communication with the internal combustion engine; a sound generator comprising a hollow drum in fluid communication with the air conduit, the drum having an outer wall with an aperture formed therein; and a sound radiation panel at least partially covering the aperture adapted to radiate sound energy to at least one of the engine compartment and the vehicle interior.
In a further embodiment, a method for manufacturing the sound generator for the vehicle includes the steps of determining a desired sound energy; determining a desired frequency range; selecting a hollow drum with an outer wall having an aperture formed therein; selecting a sound radiation panel, wherein at least one of the drum and the sound radiation panel is selected to have a tunable parameter sufficient to provide the desired sound energy and the desired frequency range; coupling the sound radiation panel to the drum to cover at least a portion of the aperture and form a sound generator; and disposing the drum and sound radiation panel in fluid communication with an air conduit of the vehicle, wherein the sound generator is tuned to the desired sound energy and desired frequency range.
The above, as well as other objects and advantages of the invention, will become readily apparent to those skilled in the art from a reading the following detailed description of the invention when considered in the light of the accompanying drawings in which:
The following detailed description and appended drawings describe and illustrate various exemplary embodiments of the invention. The description and drawings serve to enable one skilled in the art to make and use the invention, and are not intended to limit the scope of the invention in any manner. In respect of the methods disclosed, the steps presented are exemplary in nature, and thus, are not necessary or critical.
In particular embodiments, the air conduit 2 is an inlet air duct, such as a cold charge duct for a turbo or supercharged engine, or a clean air duct for a normally-aspirated engine, in fluid communication with the air induction system. As a nonlimiting example, the air conduit 2 may be disposed between an air filter and a throttle body of the air induction system. In other embodiments, the air conduit 2 is an exhaust air duct in fluid communication with the air exhaust system. The air conduit 2 includes at least one high acoustic pressure area zone that may be used for sound generation, for example.
A sound generator 4 is in fluid communication with the air conduit 2. The sound generator 4 includes a drum 6 having a cavity 7 formed therein which is defined, at least in part, by a wall 8 of the drum 6. The cavity 7 is configured to 1) provide amplification of the acoustic pressure waves or “noise” from the air conduit 2, and 2) provide tuning for a coupled or uncoupled acoustic response of the sound generator 4. The drum 6 and cavity 7 may have any suitable shape, as desired. In a particular embodiment, the drum 6 has a circular shape in cross section. In another embodiment, the drum 6 has a rectangular shape in cross section. The drum 6 has an aperture 9 formed therein. The aperture 9 provides communication between the cavity 7 of the drum 6 and the atmosphere.
The sound generator 4 further includes a connector conduit 12. The connector conduit 12 is coupled to the air conduit 2, and provides fluid communication between the air conduit 2 and the sound generator 4. In an illustrative embodiment, the connector conduit 12 provides a lesser volume than a volume represented by the cavity 7 of the sound generator 4. For example, the connector 12 may be adapted to tune the response frequency of cavity 7 to either coupled or uncoupled with the sound radiation panel 10 response frequency. In another embodiment, the connector 12 may be adapted to control the sound energy transmitted from the air conduit 2 to the cavity 7. A suitable connector conduit 12 size may be selected as desired.
A skilled artisan should understand that the drum 6 may be formed from any suitable material as desired. For example, suitable materials may include at least one of a thermoplastic, a thermoset, a metal, and a composite material. In particular embodiments the drum may be formed by one of an injection molding and a blow molding process with a thermoplastic or a thermoset material. One of ordinary skill in the art should also appreciate that suitable dimensions of the cavity 7 may be selected, for example, to generate a desired amount of the acoustic pressure waves to the air conduit 2.
The sound generator 4 of the disclosure also has at least one sound radiation panel 10 which covers the aperture 9. The sound radiation panel 10 is both structurally and acoustically coupled to the drum 6. As used herein, the term “acoustically coupled” means that the sound radiation panel 10 is adapted to convert noise in the cavity 7 of the drum 6 into sound energy in a desired frequency range. For example, the sound radiation panel 10 is adapted to vibrate in response to the acoustic pressure waves routed from the air conduit to the drum cavity 7, and thereby radiate the desired sound energy. It should also be understood that the sound radiation panel 10 may be selected as desired to have multiple modes of vibration in a particular frequency range, thereby providing an optimized sound energy over a broad frequency range, for example.
The sound energy from the sound generator 4 is directed by the sound radiation panel 10 toward at least one of the engine compartment and the vehicle interior. The sound in at least one of the vehicle interior and the vehicle exterior is thereby modulated.
The sound radiation panel 10 is formed from a material suitable for transmitting sound energy. Suitable materials include, for example, at least on of a metal, a polymer, and a composite material. Illustratively, the sound radiation panel 10 may be a plate formed of a metal selected from one of brass and stainless steel. The sound radiation panel 10 may also be a rubber or composite diaphragm, for example. In particular embodiments, the sound radiation panel 10 is a substantially flexible panel having a thickness that may range from a thin membrane to a plate. A skilled artisan should appreciate that suitable materials and plate thicknesses may be selected to produce a desired frequency in response to the sound energy delivered thereto. The suitable materials and plate dimensions may also provide a sound radiation panel 10 that is substantially insensitive to temperature and humidity changes, which typically occur during vehicle operation. Such changes in temperature and humidity can result in an undesirable shift in the desired frequency produced by the sound radiation panel of polymeric springs-mass systems in sound generators of the art.
In one embodiment, the sound radiation panel 10 may be integrally formed with the wall 8 of the drum 6. For example, the sound radiation panel 10 may be a thinned-out portion of the wall 8. Alternatively, the sound radiation panel 10 may be an independent component affixed to the drum 6. For example, the sound radiation panel 10 may be removably coupled to the drum 6, such as by clamping.
It should be understood that the sound radiation panel 10 may be removable. Being removable, different sound radiation panels 10 may be employed as desired to provide selective tuning of the sound generator 4. Alternatively, the sound radiation panel 10 may be permanently coupled to the drum 6, such as by welding of the sound radiation panel 10 to the drum wall 8.
As shown in
The platform 14 illustrated in
In a particular embodiment, a sealing channel 18 is disposed between the platform 14 and the aperture 9. The sealing channel 18 receives a peripheral edge of the sound radiation panel 10. A substantially air tight seal may thereby be formed when the cover plate 16 is affixed to the platform 14 of the drum 6.
In
As shown in
The sound generator 4 also may have at least one interior wall 24, as illustrated in
Another embodiment of the disclosure is shown in
With reference to
The present disclosure also includes a method for manufacturing the sound generator 4, 4′ for the vehicle. The method first includes the steps of determining a desired sound energy and a desired frequency range. At least one of the desired sound energy and the desired frequency range are employed to modulate sound quality in at least one of an engine compartment and a vehicle interior. For example, if the desired purpose for the sound generator is to act as a resonator in the vehicle, a sufficient sound energy and frequency that is 180 degrees out of phase with a targeted noise may be determined. Alternatively, a desired sound energy and frequency range for providing an aesthetically pleasing vehicle sound may be determined. Any known means for determining the requisite sound energy and frequency range for at least one of these purposes may be used.
The method includes a step of selecting a drum 6, 6′ having a cavity 7, 7′ formed therein. An aperture 9, 9′ is formed in a wall 8, 8′ of the drum 6, 6′. A sound radiation panel 10, 10′ is also selected. At least one of the drum 6, 6′ and the sound radiation panel 10, 10′ are selected to have a tunable parameter sufficient to provide the desired sound energy and frequency ranges determined in the initial steps of the method. The tunable parameter may include at least one of a drum material, a cavity volume, a cavity length, a drum wall thickness, a panel material, a panel surface area, a panel thickness, a connector length, and a connector volume.
The sound radiation panel 10, 10′ is then structurally and acoustically coupled to the drum 6, 6′ adjacent the aperture 9, 9′. The drum 6, 6′ is further disposed in fluid communication with the air conduit 2 of the vehicle. The sound generator 4, 4′, tuned to the desired sound energy and frequency ranges, is thereby provided.
As should be appreciated, the sound generator 4, 4′ of the present disclosure is particularly suitable for use in a motor vehicle having an internal combustion engine. The sound generator 4, 4′ is readily configurable to meet various tuning requirements, for example, by selecting the drum 6, 6′ and the panels 10, 10′ having the desired tunable parameters, or interchanging the panels 10, 10′ in the drum 6, 6′ as desired. Thus, the sound generator 4, 4′ may be selectively configured to perform as a resonator and suppress sound in at least one of the vehicle interior and exterior, or to provide additional and aesthetically pleasing sound for high performance or sports car applications.
It is also surprisingly found that a single sound radiation panel 10, 10′ may have multiple modes of vibration in a desired frequency range. Having the multiple modes of vibration may result in a greater sound energy over a larger frequency range than with single resonant frequency devices known in the art. The sound generator 4, 4′ is also less structurally complex, having only a single cavity 7, 7′, for example, than known sound generators or resonators. Favorable results have been obtained for the radiation panel 10, 10′ having multiple modes of vibration in a desired frequency range using a sound radiation panel 10, 10′ produced from a metal material.
From the foregoing description, one ordinarily skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications to the invention to adapt it to various usages and conditions.