System and method for managing noise and vibration in a vehicle using electro-dynamic regenerative force and vehicle having same

A system for managing noise and vibration in a vehicle includes a housing defining an internal cavity. A compliant member is attached to the housing and further defines the internal cavity. A magnet is operatively fixed to the housing in the cavity and has a magnetic field. A coil is positioned in the cavity and is configured so that there is relative movement between the coil and the magnet in the magnetic field in response to movement of the compliant member relative to the housing. A resistor is in electrical communication with the coil to form an electrical circuit. Relative movement of the coil in the magnetic field induces a current in the circuit that creates an opposing magnetic field, thereby reducing transmitted dynamic forces.

TECHNICAL FIELD

The present teachings generally include a system for managing noise and vibration in a vehicle using electro-dynamic regenerative force.

BACKGROUND

A vehicle has hundreds of interconnected components. Movement of one or more of these components relative to the other components is managed with dampers and mounts. For example, noise and vibration of the engine due to periodic firing in the cylinders is managed to control transmission to the vehicle body through the use of engine mounts. Some engine mounts are considered passive systems because they rely on hydraulic or damping mechanisms to manage noise and vibration transmission without active controls. Other engine mounts are considered active systems because an electronic controller ultimately controls the operation of the engine mount using feedback of vehicle operating parameters. Active engine mounts are generally more complex and more expensive than passive engine mounts.

SUMMARY

A system for managing noise and vibration in a vehicle includes a housing defining an internal cavity. A compliant member is attached to the housing and further defines the internal cavity. A magnet is operatively fixed to the housing in the cavity and has a magnetic field. A coil is positioned in the cavity and is configured such that there is relative movement between the coil and the magnet in the magnetic field in response to movement of the compliant member relative to the housing.

A resistor can be placed in electrical communication with the coil to form an electrical circuit. Movement of the coil in the magnetic field induces a current in the circuit that creates an opposing magnetic field proportional to the relative movement between the coil and the magnetic field, thereby reducing the transmitted dynamic forces

In other words, the induced current creates a regenerative force that opposes a force applied to the compliant member. Because the induced current is automatically generated and is automatically proportionate to the applied force, the system is referred to as a passive system. In other embodiments, the system can be active, such as by controlling a switch that allows current from a battery to be supplied to the coil in a first position, and closes the circuit with the resistor in a second position. When the switch is in the first position, the actively supplied current can create additional motion of the coil. A processor can execute a stored algorithm by which the processor moves the switch to the first position to place the battery in communication with the coil only during predetermined vehicle operating parameters, such as vibration above a predetermined frequency.

DETAILED DESCRIPTION

Referring to the drawings,FIG. 1shows a vehicle10that includes a first vehicle component, which in this embodiment is an engine12, operatively mounted with respect to a second vehicle component, which in this embodiment is the vehicle body14. The vehicle components are not limited to an engine and a vehicle body, and instead can be any two components between which it is desired to manage (passively or actively) the transmission of vibration and noise. For example, the first vehicle component could be a transmission, and the second vehicle component could be a vehicle frame. As explained in further detail herein, the vehicle10includes a vibration and noise management system16that includes an electro-dynamic mount18and utilizes back electromotive force (i.e., regenerative force) generated by induced current to affect movement of the electro-dynamic mount18operatively connected to the engine12, and thereby mitigate the transmission of noise and vibration from the engine to the vehicle body14. The system16can be entirely passive. In an alternate embodiment shown inFIG. 4, the electro-dynamic mount18can be actively controlled. Although only one system16is shown operatively connected to the engine12, similar systems16can be used at additional locations at which the engine12is mounted relative to the body14.

The system16includes a housing20defining an internal cavity22. A first compliant member24is attached to the housing20and further defines the internal cavity22. The housing20may be a rigid material, such as steel, and the compliant member24is a flexible and resilient material such as rubber. The housing20is shown in a schematic cross-sectional view, and can have a circular, square, or rectangular periphery, or any other suitable shape. The compliant member24has a complementary shape allowing an outer periphery26of the compliant member24to be frictionally engaged with or secured to an inner periphery28of the housing20by adhesive bonding, structural adhesive, fasteners, or any other suitable means. A center support30is secured to the compliant member24and is secured to a bracket32by a fastener34. The bracket32is secured to a boss36of the engine12by a separate fastener38. Any other suitable means can be used to secure the engine12to the compliant member24such that vertical movement of the engine12, resulting in an applied force39(represented by a double-sided arrow) on the system16, is transmitted to the compliant member24.

The electro-dynamic mount18includes a magnet40operatively fixed to the housing20in the cavity22. The magnet40is a permanent magnet. By way of nonlimiting example, it can be assumed that the magnet40is arranged inFIG. 1so that it has a magnetic field with field lines that extend out of the page inFIG. 1. The electro-dynamic mount18also includes a coil42positioned in the cavity22. The coil42is an annular coil that is configured to be movable relative to the magnet40in the magnetic field in response to movement of the compliant member24relative to the housing20as further described herein. In another embodiment within the scope of the claimed invention, the coil42and the magnet40can be configured to move the magnet40relative to the coil42in response to movement of the compliant member24relative to the housing20. In such an embodiment, the coil42would be fixed to the housing20, and the magnet40would be operatively connected to the compliant member24.

The coil42is wound in an annular configuration and has a first end44A and a second end44B that are electrically connected by wiring to a resistor46to form a closed electrical circuit48. Vertical movement of the coil42relative to the magnet40and the field of the magnet40will cause a change in magnetic flux passing through the coil42. Because the resistor46is connected to form a closed circuit with the coil42, a current will be induced to flow in the circuit48through the coil42and the resistor46due to the change in magnetic flux. According to Lenz's law, the induced current has an electromotive force that opposes the force that caused the change in magnetic flux (i.e., a force that opposes the force that caused the coil42to move).

The electro-dynamic mount18includes a diaphragm50extending to an inner housing support58of the housing20at an outer periphery52and operatively connected to the coil42at an inner periphery54through a center mount56. Inner housing supports58structurally support the diaphragm50and the magnet40relative to the housing20. The diaphragm50separates the internal cavity22into a first portion60and a second portion62. The first portion60is between the compliant member24and the diaphragm50and contains a first incompressible fluid64, such as hydraulic fluid including glycol. The second portion62contains the magnet40, the coil42, and the resistor46and is filled with air. Forces acting on the compliant member24are transferred to the diaphragm50by the first fluid64. Because the coil42is fixed to the diaphragm50by the mount56, the coil42also moves when the diaphragm50moves due to the forces on the compliant member24. The degree of movement of the coil42depends on the stiffness of the electro-dynamic mount18, which is partially dependent on the stiffness of the diaphragm50.

Movement of the coil42in the magnetic field induces a current in the circuit48that creates an opposing magnetic field proportional to the change in magnetic flux through the coil42. In other words, the opposing magnetic field is opposite to the “parent” magnetic field of the magnet40and is proportional to the movement of the coil42in the parent magnetic field. The opposing magnetic field is associated with a net force on the coil42, which is opposite and out-of-phase at all times to the direction of movement of the coil42. Because the movement of the coil42is proportional to the movement of the engine12, this results in an opposing force on the coil. The opposing force is transmitted to the body14, which reduces the transmitted force due to the movement of the engine12. Vibration and/or noise of the engine12may be sinusoidal, causing the induced current and opposing force to be sinusoidal, and in direct opposition to the applied force39. Accordingly, although the system16is entirely passive in that it is without an electronic controller to control transmitted noise and vibration based on feedback of operating conditions, the system16provides vibration mitigation that is automatically in proportion to the varying applied force39because the induced current is proportionate to the change in magnetic flux through the coil42.

FIG. 2schematically represents the opposing force F resulting from the induced current in the coil42when the coil42moves downward toward the magnet40from a position A to a position B (shown in phantom) due to the applied force39ofFIG. 1being momentarily downward. Only the upper extent70of the coil42at ends44A,44B is shown. The magnetic flux increases as the coil42moves through more of the toriodal-shaped parent magnetic field72(only a portion of which is shown). The induced current I is clockwise in the coil42, as the induced current I has an opposing magnetic field that opposes the change in magnetic flux that induced the current, and a resulting opposing force F that opposes the applied force39.

Referring again toFIG. 1, an optional hydraulic mount76, also referred to as a hydraulic damper, is placed in parallel with the electro-dynamic mount18in the housing20to further mitigate the transmission of engine noise and vibration to the body14. The hydraulic mount76is positioned in parallel with the diaphragm50in the housing20. The hydraulic mount76includes the inner housing support58that forms a passage78. The inner housing support58and passage78function as an inertia track that divides the first portion60of the internal cavity22into a first fluid cavity80and a second fluid cavity82, with the passage78fluidly connecting the first fluid cavity80with the second fluid cavity82.

The hydraulic mount76includes a second compliant member84positioned in the second fluid cavity82. The second compliant member84is shown as bellows secured to the housing20and the support58, but can be any suitable compliant member. The second compliant member84is flexible, and is therefore operable to vary a volume of the second fluid cavity82in response to flow of the first fluid64through the passage78. When the first compliant member24moves due to the vibrations of the engine12, the incompressible fluid64is forced through the passage78between the first fluid cavity80and the second fluid cavity82. The arrows77represent the fluid64moving from the first cavity80to the second cavity82, consistent with a momentary downward force39on the first compliant member24. In that instance, the second compliant member84flexes outward toward the bottom of the housing20into an air cavity86on an opposite side of the second compliant member84, expanding the second fluid cavity82. Air can be forced out of the air cavity86to atmosphere through one or more openings88in the housing20. Fluid64can also move from the second fluid cavity82to the first fluid cavity80when the momentary force39moves the first compliant member24upward, causing the second fluid cavity82to decrease in size and the second compliant member84to flex away from the housing20, drawing air into the air cavity86through the openings88. Because the passage78is a restriction between the fluid cavities80,82, and fluid64must travel through the restrictive passage78when the first compliant member24moves, the passage78slows movement of the fluid64between the cavities80,82, and further mitigates movement of the first compliant member24relative to the housing20, lessening the transmission of noise and vibration to the body14.

Although the hydraulic mount76is shown in parallel with the electro-dynamic mount18in the vibration and noise management system16ofFIG. 1, an alternate vibration and noise management system16A shown inFIG. 3includes only the passive electro-dynamic mount18with the resistor46and without an electronic controller. The electro-dynamic mount18of the system16A includes the diaphragm50, center mount56, support member58, housing20, coil42, and magnet40. The support member58as used in system16A would not include passage78. The diaphragm50could be larger in system16A to extend to the inner periphery28of the housing20, and the support member58could be eliminated, as there is no hydraulic mount76.

FIG. 4shows an alternative vibration and noise management system16B for a vehicle such as vehicle10, in which active control of vibration and noise management is available in addition to the passive control possible with the electro-dynamic mount18A with resistor46. Specifically, a switch90is actively controlled by a processor92to be selectively moved to implement a passive mode or an active mode in response to predetermined vehicle operating parameters. The switch90and the processor92are shown integrated in an electronic control module85(also referred to herein as an electronic controller). The switch90and the resistor46are provided on a switching module89included in the electronic control module85. Alternatively, the switching module89could be separate from the electronic control module85. The processor92is operatively connected to the switch90by the conductors96,98over which electrical signals and electrical current can be communicated. When in a first position that enables the active mode (shown in phantom as90A inFIG. 4), the switch90closes an active mode circuit to enable current from a battery91to be supplied to the coil of the electro-dynamic mount18A (like coil42shown inFIG. 1) along conductor87, and at the same time opens a passive mode circuit that includes the resistor46. The switch90is moved by the processor92according to an algorithm stored on the processor92that is executed by the processor92. The electronic control module85is grounded at ground G. The algorithm can be configured so that the processor92moves the switch90to the first position90A in response to a control signal93from an engine control module (ECM)94or in response to other input signals95to enable current from the battery91to be supplied to the coil42regardless of relative movement of the coil42, if desired. For example, current can be supplied to the coil42even when there is no relative motion between the coil42and the magnet40to thereby vary the stiffness of the electro-dynamic mount18A. The algorithm can also be configured so that the battery91provides current to the coil42when the coil42is moving due to force39on the compliant member24ofFIG. 1, with the supplied current being configured to have a direction in the coil42that generates an opposing force to the applied force39. In other words, the induced current generated by movement of the coil42in the parent field of the magnet40that occurs automatically can be alternated between active and passive control. Access to the coil42of the mount18A can be through an electrical connector that extends through a housing20like housing20ofFIG. 1. The conductors97,99would connect to the coil42through the electrical connector. The electronic control module85including the switch90and the resistor46would be moved outside of the housing20.

The processor92may be configured to move the switch90based on vehicle operating parameters input as signals93to the electronic control module85from the ECM94, and as signals95from other sensors or control modules (not shown) on the vehicle that are in electronic communication with the electronic control module85. In the embodiment shown, the vehicle operating parameters supplied as input signals93by the ECM94include, by way of nonlimiting example, the pulses per revolution of the engine12ofFIG. 1. By way of nonlimiting example, additional vehicle operating parameters supplied as input signals93or95to the electronic control module85include engine speed (such as in revolutions per minute), engine torque (such as in Newton-meters (N-m)), gear state of a transmission operatively connected to the vehicle, and engine temperature.

The stored algorithm includes determining one or more operating parameters of the vehicle10, based on the one or more input signals93,95. The processor92then enables electrical current to be provided from the battery91to the coil42of the electro-dynamic mount18A when the one of more operating parameters are within a first predetermined range of values such as a frequency of vibration greater than a predetermined frequency. The electrical current is provided from the battery91when the processor92moves the switch90to the first position90A. When the switch90is in the first position90A, the resistor46is not operatively connected to the coil42(i.e., the resistor46is operatively disconnected from the coil42). Additionally, if the switch90is in the first position90A, and the algorithm determines that the operating parameters are not within the first predetermined range of values, then the processor92will move the switch90to a second position90B, which enables the passive mode in which the battery91is not operatively connected to the electro-dynamic mount18A (i.e., the battery91is operatively disconnected from the coil42) and the electro-dynamic mount18A is in a closed circuit with the resistor46.

By way of nonlimiting example, the algorithm can determine from the input signals93,95whether the frequency of engine vibration is expected to be within a first range of frequencies, or within a second range of frequencies. For example, the first range of frequencies can be from 0-200 Hertz (referred to herein as a second predetermined range of values), and the second range of frequencies can include frequencies greater than 200 Hertz (referred to herein as a first predetermined range of values), although other frequency ranges can instead be used. In the first range of frequencies, the opposing force generated by the induced current in the coil42of the electro-dynamic mount18with resistor46connected in closed circuit48may be sufficient to mitigate vibrations. Vibration management of the system16B is thus entirely passive in the first range of frequencies. The switch90is in the second position90B during the first range of frequencies. In the second range of frequencies, the processor92moves the switch90to the first position90A so that the resistor circuit is opened and current is actively supplied from the battery91in the active mode such as to generate motion of the coil of the electro-dynamic mount18, thereby optionally increasing the opposing force. The hydraulic mount76shown inFIG. 1can optionally be used in parallel with the electro-dynamic mount18A in the actively controlled system16B.

FIG. 5illustrates the effect of adding the resistor46to the electro-dynamic mount18ofFIG. 1. The plot ofFIG. 5shows a mathematical model indicating the expected transmissibility100of engine vibration to the vehicle body14on the Y-axis as a dimensionless ratio of transmitted force on the body14to the input force39of the engine12on the compliant member24. The axial frequency102in Hertz of the vibration of the engine12is indicated on the X-axis (where axial frequency is the frequency of vibration about an axis through the crankshaft of the engine12). Resonance of the mount18causes the transmissibility100to be greater than one over a certain axial frequency range. Curve104shows the transmissibility100when the electro-dynamic mount18ofFIG. 1does not include the resistor46, so that the coil42is not in a closed circuit and no induced current can flow in the coil42. Curve106shows the transmissibility100when the resistor46is added in closed circuit to the coil42, and indicates that transmissibility100is reduced especially in the range of frequencies near the resonant frequency of the mount18due to the opposing force of the induced current.

Accordingly, by adding a resistor46to create a closed circuit with the coil42in an electro-dynamic mount18, passive noise and vibration management is possible such as in systems16and16A. Optionally, noise and vibration can be actively managed by adding a switch90that is controlled to enable selectively adding current to the coil42from a battery91to the electro-dynamic mount18A and/or to switch to a passive operation of the electro-dynamic mount18A, such as in system16B.

While the best modes for carrying out the many aspects of the present teachings have been described in detail, those familiar with the art to which these teachings relate will recognize various alternative aspects for practicing the present teachings that are within the scope of the appended claims.