Vehicle noise-generating component estimation device

Abstract

The present invention provides a vehicle noise-generating component estimation device that can estimate which of two motors is generating noise. [Solution] The first noise level is measured when the same torque is output from the first motor and the second motor. The second noise level is measured when the torque of one of the motors is increased and the torque of the other motor is decreased (step S8). If the second noise level is higher than the first noise level, it is estimated that the noise is being generated from one of the motors (step S11). If the second noise level is lower than the first noise level, it is estimated that the noise is being generated from the other motor (step S13).

Description

Technical Field

[0001] This invention relates to an apparatus for estimating a motor that generates noise among two motors provided as a driving power source of a vehicle.

Background Art

[0002] Patent Document 1 describes a sound source estimation system for identifying a component that causes abnormal noise among a plurality of components mounted on a vehicle. This sound source estimation system extracts sound of a frequency that a user feels as abnormal noise from sound data generated by driving the vehicle, and is configured to identify a component that may generate a rotation order based on the frequency of the extracted sound as the cause of the abnormal noise. Specifically, it is determined based on a user operation or the like whether the sound data generated by driving the vehicle contains abnormal noise, and analysis sound data obtained by excluding noise other than the abnormal noise from the sound data containing the abnormal noise and analysis rotation speed data are generated. Subsequently, based on the analysis sound data and the analysis rotation speed data, the maximum sound frequency, which is the frequency indicating the maximum sound pressure, is extracted every predetermined time, and the order of the maximum sound frequency data is calculated. Then, a component that becomes a candidate for the sound source of the abnormal noise is estimated based on the calculated order.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The sound source estimation system described in Patent Document 1 is configured to identify the component (mainly gears) causing the abnormal noise based on the order of a specific frequency contained in the detected sound data. However, in a vehicle equipped with a right-side motor connected to the right-side drive wheel, a left-side motor connected to the left-side drive wheel and configured identically to the right-side motor, and a case housing these motors, each motor outputs the same rotational speed and torque when the vehicle is traveling in a straight line. Therefore, the order of the abnormal noise generated when a malfunction occurs in each motor will be the same. Consequently, even if the order of a specific frequency contained in the detected sound data is determined, as in the sound source estimation system described in Patent Document 1, it may not be possible to determine whether the abnormal noise is originating from the right-side motor or the left-side motor.

[0005] This invention was made in view of the above-mentioned technical problems, and aims to provide a vehicle noise-generating component estimation device that can estimate which of two motors is generating noise. [Means for solving the problem]

[0006] To achieve the above objective, this invention provides a vehicle noise-generating component estimation device comprising a first motor connected to one of a pair of left and right drive wheels, a second motor connected to the other drive wheel, and a case housing the first motor and the second motor, wherein the device comprises a measuring instrument for measuring noise when the first motor and the second motor are driven, and a controller for estimating which of the first motor and the second motor is generating the noise based on the noise data measured by the measuring instrument, the controller measuring a first noise level when the same torque is output from the first motor and the second motor, measuring a second noise level when the torque of one of the first motor and the torque of the other motor is increased, estimating that the noise is generating from the one motor when the second noise level is higher than the first noise level, and estimating that the noise is generating from the other motor when the second noise level is lower than the first noise level. [Effects of the Invention]

[0007] According to this invention, a first motor is connected to one of a pair of left and right drive wheels, and a second motor is connected to the other drive wheel. That is, when the vehicle is traveling in a straight line, the first motor and the second motor rotate at the same rotational speed and output the same torque. Furthermore, these motors are housed in a single case. Therefore, by measuring the second noise level when the torque of one motor is increased and the torque of the other motor is decreased, and comparing it with the first noise level when the same torque is output from each motor, it can be estimated that noise is being generated from one motor when the second noise level increases, and conversely, it can be estimated that noise is being generated from the other motor when the second noise level decreases. [Brief explanation of the drawing]

[0008] [Figure 1]This figure schematically shows an example of a vehicle equipped with a first motor and a second motor according to an embodiment of this invention. [Figure 2] This is a flowchart illustrating an example of the control performed by the noise-generating component estimation device in this embodiment of the invention. [Figure 3] This is a flowchart illustrating an example of a mode for identifying the motor causing abnormal noise, which is performed by the noise-generating component estimation device in this embodiment of the invention. [Modes for carrying out the invention]

[0009] This invention will be described based on the embodiments shown in the figures. The embodiments described below are merely examples of how this invention can be implemented and do not limit it.

[0010] Figure 1 schematically shows an example of a vehicle Ve equipped with a noise-generating component estimation device according to an embodiment of the present invention. The vehicle Ve shown in Figure 1 is equipped with a left motor (MG1) 2L connected to the left drive wheel 1L and a right motor (MG2) 2R connected to the right drive wheel 1R. These motors 2L and 2R can be configured as three-phase AC type permanent magnet synchronous motors, similar to motors provided as driving force sources in conventional electric vehicles and hybrid vehicles. That is, they are composed of a rotor, a cylindrical stator arranged to surround the outer circumference of the rotor, a plurality of permanent magnets provided at predetermined intervals in the circumferential direction of the rotor, and a plurality of coils provided at predetermined intervals in the circumferential direction of the stator. Note that each of the above motors 2L and 2R may be provided to drive a pair of front wheels or a pair of rear wheels. The above left motor 2L and right motor 2R correspond to the "first motor" and "second motor" in the embodiment of the present invention.

[0011] Each of the motors 2L and 2R described above is configured similarly. That is, the shape of the stator and rotor, the number of coil turns, and the rotor support structure are all identical. For convenience, Figure 1 shows an example where each motor 2L and 2R is directly connected to the drive wheels 1L and 1R, but a power transmission mechanism such as a reduction gear may be provided between the motors 2L and 2R and the drive wheels 1L and 1R. In that case, it is preferable that the gear ratios of the left and right power transmission mechanisms are the same.

[0012] Furthermore, each motor 2L and 2R is housed in an integrated case 3. Specifically, case 3 is constructed by arranging a left-side case 3L, which houses the left-side motor 2L, and a right-side case 3R, which houses the right-side motor 2R, side by side and fixing them together with bolts or the like. This case 3 is fixed to the vehicle body.

[0013] The left motor 2L is connected to a left power control unit (PCU1) 4L, which includes an inverter that converts DC power output from a power storage device (not shown) into AC power for energization, and also converts AC power generated by the rotation of the left motor 2L into DC power for supply to the power storage device. Similarly, the right motor 2R is connected to a right power control unit (PCU2) 4R, which includes an inverter that converts DC power output from a power storage device (not shown) into AC power for energization, and also converts AC power generated by the rotation of the right motor 2R into DC power for supply to the power storage device. Note that these power control units 4L and 4R may be identically configured and capable of exchanging power with each other.

[0014] An ammeter 5L is provided between the left motor 2L and the left power control unit 4L to measure the current flowing through the left motor 2L (coil). Similarly, an ammeter 5R is provided between the right motor 2R and the right power control unit 4R to measure the current flowing through the right motor 2R (coil). At least two of each ammeter 5L and 5R are provided to measure the current flowing through the U-phase, V-phase, and W-phase, respectively.

[0015] These motors 2L and 2R are driven by controlling the voltage applied to each phase according to the rotation angle. Therefore, a left resolver 6L is provided to detect the rotation angle of the left motor 2L, and a right resolver 6R is provided to detect the rotation angle of the right motor 2R. In addition, the vehicle Ve is equipped with a microphone 7 for detecting sound in a predetermined space such as the interior of the vehicle, and a G sensor 8 for detecting vibration (acceleration) of the case 3. These microphone 7 and G sensor 8 correspond to the "measuring instruments" in this embodiment of the invention.

[0016] Furthermore, the above-mentioned vehicle Ve is equipped with a controller (ECU) 9 for estimating the components that generate vibrations and abnormal noises (hereinafter collectively referred to as noise). This controller 9 is mainly composed of a microcomputer and is configured to receive signals from the above-mentioned ammeters 5L, 5R, resolvers 6L, 6R, microphone 7, and G sensor 8, and to estimate the components that generate the noise based on the input signals and pre-stored calculation formulas and maps.

[0017] Figure 2 shows a flowchart illustrating an example of the control performed by the controller 9. In the control example shown in Figure 2, first, noise data D0, motor torque T0, and motor rotation speed N0 are acquired during straight-line driving (step S1). The noise data D0 in step S1 is at least one of the following noise data: sound data from inside the vehicle, vibration data from the drive unit including each motor 2L, 2R, and sound data radiated from the drive unit, and can be acquired by reading the signals detected by the microphone 7 and G sensor 8. The motor torque T0 can be acquired by calculating it based on the current values ​​detected by each ammeter 5L, 5R. The motor rotation speed N0 can be acquired by reading the signals detected by each resolver 6L, 6R. Alternatively, the motor torque T0 may be acquired by providing a torque sensor on the output shaft of each motor 2L, 2R and reading the detected signal.

[0018] Step S2 involves determining the noise order through order analysis using the motor rotation speed N0 obtained in step S1. Specifically, for example, the noise level for each frequency is obtained by performing an FFT analysis on the noise data D0 obtained in step S1, and the frequency component with the largest noise level is extracted. Subsequently, the noise order is determined by dividing the extracted frequency by the motor rotation speed N0.

[0019] Step S3 determines whether the order identified in step S2 (hereinafter referred to as the noise order) matches the order of the noise generated by driving motors 2L and 2R (hereinafter referred to as motor noise). This motor noise is noise generated by electromagnetic factors, and the order of this noise generated by electromagnetic factors is an integer multiple of the number of pole pairs of magnets provided on the rotor. For example, if there are four magnets on the rotor and the number of pole pairs is four, the rotational order of the electromagnetic factors will be the 8th, 16th, 24th order, etc.

[0020] When the noise order is affirmatively determined in step S3 because it matches the order of the motor noise, it is determined whether two motors that independently drive one pair of drive wheels, either the front wheels or the rear wheels, are provided and mounted in an integrated case (step S4). Since it is assumed that the controller 9 does not store information such as the specifications of the vehicle Ve, step S4 is being determined. The vehicle Ve shown in FIG. 1 includes a left motor 2L and a right motor 2R so that one pair of drive wheels can be independently driven, and since those motors 2L, 2R are mounted in the case 3, it is affirmatively determined in step S4. Note that step S4 can be determined based on information read from other ECUs or the like, or based on a signal input by the user.

[0021] When it is affirmatively determined in step S4, it is determined whether the left and right motors 2L, 2R are independently controlled (step S5). This step S5 is also a judgment step on the premise that information such as the specifications of the vehicle Ve is not stored, similar to step S4. Specifically, even in the case of a vehicle equipped with two motors, there may be a vehicle in which the same PCU applies voltage to those motors for driving, and this is a step to exclude such a vehicle from the control target. In the vehicle Ve shown in FIG. 1, power control units 4L, 4R are provided corresponding to the respective motors 2L, 2R, and by independently controlling those power control units 4L, 4R, each motor 2L, 2R is independently driven, so it is affirmatively determined in step S5. Note that step S5 can also be determined based on information read from other ECUs or the like, or based on a signal input by the user.

[0022] If it is affirmatively determined in step S5, the process proceeds to the abnormal noise cause motor identification mode. On the other hand, if it is negatively determined in step S3 because the noise order does not match the motor noise order, or if it is negatively determined in step S4 because the vehicle does not have two motors for independently driving either the front wheels or the rear wheels, or because the two motors are not mounted in an integrated case, or if it is negatively determined in step S5 because the left and right motors 2L and 2R are not independently controlled, it is difficult to identify the cause of the abnormal noise by this control example, so this routine is terminated once as it is. Note that it may be indicated that it is difficult to identify the cause of the abnormal noise, or a plurality of other candidates for the cause of the abnormal noise may be output.

[0023] FIG. 3 shows a flowchart for explaining an example of the control executed in the abnormal noise cause motor identification mode. In the example shown in FIG. 3, first, the user is prompted to perform turning travel, for example, by displaying it on a monitor provided in the vehicle Ve, and the motor torque and noise data at that time are associated and stored (step S6).

[0024] Next, it is determined whether there is data in the motor torque information stored in step S6 such that the torque difference between the left and right motors 2L and 2R is greater than or equal to a predetermined difference, and the torque of one of the motors 2L (2R) is smaller than the motor torque T0 obtained in step S1, and the torque of the other motor 2R (2L) is greater than the motor torque T0 obtained in step S1 (step S7). The predetermined difference in step S7 may be determined based on the weight of the vehicle Ve, the sizes of the motors 2L and 2R, and the like.

[0025] If the motor torque data stored in step S6 does not contain data where the torque difference between the left and right motors 2L and 2R is greater than or equal to a predetermined difference, or where the torque of one motor 2L (2R) is less than the motor torque T0 obtained in step S1 and the torque of the other motor 2R (2L) is greater than the motor torque T0 obtained in step S1, and a negative determination is made in step S7 because the user does not perform a turning maneuver, or the turning radius during turning maneuvers is large, then it is difficult to identify the cause of the abnormal noise using this control example, and this routine is terminated. Alternatively, a message indicating that it is difficult to identify the cause of the abnormal noise, or several other possible causes of the abnormal noise, may be output. Alternatively, the system may return to step S6 to prompt the user to perform a turning maneuver again in order to obtain the necessary data.

[0026] Conversely, if the motor torque information stored in step S6 contains data indicating that the torque difference between the left and right motors 2L and 2R is greater than or equal to a predetermined difference, and that the torque of one motor 2L (2R) is smaller than the motor torque T0 acquired in step S1, and the torque of the other motor 2R (2L) is larger than the motor torque T0 acquired in step S1, and thus a positive determination is made in step S7, then noise data D1 for that turning run is acquired (step S8). Step S8 only requires reading the noise data associated in step S6.

[0027] Next, it is determined whether the motor torque T1 of the right motor 2R is greater than the motor torque T2 of the left motor 2L (step S9). If it is determined positively in step S9 that the motor torque T1 of the right motor 2R is greater than the motor torque T2 of the left motor 2L, it is determined whether the noise level has worsened compared to the noise data D0 during straight-line driving (step S10). That is, it is determined whether the noise level in the noise data D1 acquired in step S8 is greater than the noise level in the noise data D0 acquired in step S1 by a predetermined level or more. The predetermined level can be set in advance, taking into account detection errors and the influence of the surrounding environment. The noise level in the noise data D0 acquired in step S1 corresponds to the "first noise level" in this embodiment of the invention, and the noise level in the noise data D1 acquired in step S8 corresponds to the "second noise level" in this embodiment of the invention.

[0028] If the noise level has worsened compared to the noise data D0 during straight-line driving, and this is positively determined in step S10, the cause of the noise during motor operation is estimated to be the right motor 2R (step S11), and the result is output (step S12).

[0029] Conversely, if the noise level is not worse than the noise data D0 during straight-line driving, or in other words, if the noise level has decreased and a negative judgment is made in step S10, then it is estimated that the cause of the noise during motor drive is the left motor 2L (step S13), and the result is output (step S14).

[0030] On the other hand, if it is determined negatively in step S9 because the motor torque T1 of the right motor 2R is smaller than the motor torque T2 of the left motor 2L, then it is determined whether the noise level has worsened compared to the noise data D0 during straight-line driving (step S15). That is, it is determined whether the noise level in the noise data D1 obtained in step S8 is greater than the noise level in the noise data D0 obtained in step S1.

[0031] If the noise level has worsened compared to the noise data D0 during straight-line driving, and this is positively determined in step S15, the cause of the noise during motor operation is estimated to be the left motor 2L (step S13), and the result is output (step S14).

[0032] Conversely, if the noise level is not worse than the noise data D0 during straight-line driving, and therefore a negative judgment is made in step S15, the cause of the noise during motor drive is estimated to be the right motor 2L (step S11), and the result is output (step S12).

[0033] As described above, the left motor 2L is connected to one of the pair of drive wheels 1L, and the right motor 2R is connected to the other drive wheel 1R. That is, when the vehicle Ve is traveling in a straight line, the left motor 2L and the right motor 2R rotate at the same speed and output the same torque. Furthermore, these motors 2L and 2R are housed in a single case 3. Therefore, by comparing the noise level when the torque of one motor 2R (2L) is increased and the torque of the other motor 2L (2R) is decreased with the noise level during straight-line travel when the same torque is output from each motor 2L and 2R, if the noise level during turning worsens (increases), it can be estimated that noise is being generated from one of the motors 2R (2L). Conversely, if the noise level during turning does not worsen (decreases), it can be estimated that noise is being generated from the other motor 2L (2R).

[0034] Furthermore, the noise-generating component estimation device in this embodiment of the invention is not limited to one mounted on the vehicle Ve, but may also be a tablet terminal or the like. Also, the vehicle Ve is not limited to driving on public roads such as in urban areas, but may be driven in a simulated manner on a chassis dynamometer or the like to change the motor torque. In that case, measuring instruments such as microphones and G sensors do not have to be permanently installed in the vehicle, but may be attached to the vehicle Ve when estimating the noise-generating components, and the noise-generating component estimation device does not have to be installed on the vehicle Ve.

[0035] Furthermore, the noise-generating component estimation device described above is not limited to estimating the noise-generating component while each motor 2L, 2R housed in case 3 is mounted on vehicle Ve. For example, each motor 2L, 2R housed in case 3 may be removed from vehicle Ve, attached to a measuring instrument, and the noise-generating component may be estimated by changing the motor torque in that state. [Explanation of Symbols]

[0036] 1L, 1R drive wheels 2L, 2R motor 3 cases 3L Left-side case 3R Right side case 5L,5R ammeter 7 Microphone 8G sensor 9 Controllers Vehicle

Claims

[Claim 1] A vehicle noise-generating component estimation device comprising a first motor connected to one of a pair of left and right drive wheels, a second motor connected to the other drive wheel, and a case housing the first motor and the second motor, A measuring instrument for measuring noise during the operation of the first motor and the second motor, The system includes a controller that estimates which of the first motor and the second motor is generating the noise based on the noise data measured by the measuring instrument, The aforementioned controller, The first noise level is measured when the same torque is output from the first motor and the second motor. The second noise level is measured when the torque of one of the first motors and the second motor is increased and the torque of the other motor is decreased. If the second noise level increases above the first noise level, it is presumed that noise is being generated from one of the motors, and if the second noise level decreases below the first noise level, it is presumed that noise is being generated from the other motor. A vehicle noise-generating component estimation device characterized by the above.

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