JPH0754283B2 - Vehicle noise measurement device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automobile noise measuring device, and more particularly to an improved noise measuring device for measuring noise when driving an automobile by a full-open acceleration running test method.

(Prior Art) Generally, there is a full-open acceleration running test method as one of the noise test methods for measuring vehicle noise when driving a vehicle.

This fully open acceleration test method is based on ISO (International Organization for Standardization) 362
Is specified as follows.

That is, as shown in FIG. 4, a BB point is provided at a distance of 20 m from the AA point, and a distance of 7.5 m from the straight running path (C-C line) of the automobile and at the AA and BB points. A pair of microphones connected to a sound level meter at each intermediate position between
To be installed.

Then, the car is A
-After passing point A, fully open the throttle to accelerate A
-Through the passage between point A and point BB and traveling through this predetermined section, the throttle is fully closed immediately.

The vehicle noise at this time is measured by a sound level meter via a microphone.

However, the test method specified by ISO 362 requires a large outdoor space and is affected by weather conditions such as rain and wind.

Therefore, conventionally, for example, in Japanese Patent Laid-Open No. 167923/1983, a chassis of a test vehicle is mounted on a drum (roller) of a chassis dynamo provided in an anechoic chamber, and the chassis is generated by rotating the drive wheel. The noise generated when the test vehicle is driven by supplying the output voltage of the dynamo to the motor that drives the endless belt on which the microphone connected to the sound level meter is placed, and moving the microphone at a speed according to the running condition of the test vehicle. A method and apparatus for measuring exterior noise for obtaining data are described.

(Problems to be Solved by the Invention) According to the vehicle exterior noise measuring method and apparatus described in JP-A-58-167923, the microphone is moved in the anechoic chamber according to the running state of the test vehicle. Since the microphone is configured to obtain noise data, a complicated and expensive driving device including an endless head, its driving mechanism, and its control device is required to move the microphone according to the vehicle speed. There is a problem that a special filter circuit for removing the wind noise is required.

(Means for Solving Problems) A vehicle noise measuring apparatus according to the present invention is a vehicle in which driving wheels of an automobile are mounted on a roller of a chassis dynamo, and noise generated when the automobile is driven is collected by a microphone and a sound level meter. In a noise measuring device for an automobile that is measured via a plurality of sound collecting microphones, which are arranged side by side in a lateral direction of the automobile at mortgage intervals, and receive a vehicle speed signal from at least one of the chassis dynamo and the automobile. There is provided a switching device that calculates a traveling distance from the vehicle speed signal and sequentially and selectively switches the sound collecting microphones so as to correspond to the traveling distance.

(Operation) In the vehicle noise measuring device according to the present invention, when the vehicle is noisy and the vehicle speed signal is output from the chassis dynamo or the vehicle, the switching device calculates the traveling distance from the vehicle speed signal and determines the traveling distance. A plurality of sound pickup microphones are sequentially and selectively switched correspondingly.

Then, the noise outside the vehicle when the vehicle is driven is measured via the sound collecting microphone and the sound level meter, which are sequentially and selectively switched.

That is, by measuring the noise by sequentially switching multiple sound collection microphones according to the automatic mileage, ISO362
Accurate noise data can be obtained by a method equivalent to.

(Effect of the Invention) According to the vehicle noise measuring device of the present invention, as described above, the traveling distance is calculated from the vehicle speed signal, and the sound collecting microphones are sequentially and selectively selected to correspond to the traveling distance. Since it is configured to measure the noise by switching, it does not require a plurality of driving devices for moving the microphone, and does not mix unnecessary noise such as wind noise.
Accurate vehicle noise data can be obtained indoors with a simple structure.

(Example) Hereinafter, the Example of this invention is described based on drawing.

The vehicle noise measuring device according to the present embodiment is for measuring the vehicle exterior noise in the running state of the vehicle in an anechoic chamber, and for the case of measuring the vehicle exterior noise by the full-open acceleration running test method of ISO362 below. explain. The X direction is the front in FIG.

In FIG. 1, a chassis dynamo 2 is a center of the anechoic chamber 3 in the left-right direction and a pair of rollers of the chassis dynamo 2.
When the drive wheels (rear wheels) of the automobile 1 are placed on the vehicle 2a, the front end of the automobile 1 is arranged at the center in the front-rear direction.

Here, the anechoic chamber 3 has a width of 15 m or more in the left-right direction and 20 m or more in the front-rear direction.

7.5m to the left from the center line CL, at a position parallel to the center line CL,
16 sound pickup microphones M _{1 to} M ₁₆ for collecting noise
Are arranged at regular intervals of 1.2 m above the ground, and the sound collecting microphones M _{1 to} M ₁₆ are connected to the channel selector 4.

With the position where the sound collecting microphone M ₁ is provided as a reference position,
A sound collecting microphone M ₁₆ is arranged 20 m behind the reference position.

On the other hand, 16 sound collecting microphones N _{1 to} N ₁₆ are arranged at positions 7.5 m to the right of the center line CL and parallel to the center line CL so as to correspond to the sound collecting microphones M _{1 to} M ₁₆ , respectively. , And the sound collecting microphones N _{1 to} N ₁₆ are connected to the channel selector 5.

Collecting microphone M ₁ via the channel selector 4
There are provided a sound level meter 16 for receiving signals from M 1 to M ₁₆ and a sound level meter 18 for receiving signals from the sound collecting microphones N _{1 to} N ₁₆ via the channel selector 5.

While selectively switching the sound collection microphones M _{1 to} M ₁₆ and N _{1 to} N ₁₆ in order to correspond to the mileage of the vehicle from a predetermined time described later (however, the mileage on the chassis dynamo), The switching device for obtaining and storing the noise value from the noise sound pressure level measured by the sound level meters 16 and 18 and printing it on the printing mechanism (not shown) comprises the channel selectors 4 and 5 and the control device C.

As shown in FIGS. 1 and 2, the control device C includes a start signal line from the key switch of the engine of the automobile 1.
L ₁ , the throttle opening signal line L ₂ from the automobile throttle opening sensor, and the speed signal line L ₃ from the chassis dynamometer 2
And sound pressure signal lines L ₄ and L ₅ from the sound level meters 16 and 18 are connected,
Further, control lines L ₆ and L ₇ are connected from the control device C to the respective channel selectors 4 and 5.

Next, as shown in the block diagram of FIG.
Is connected to the CPU (Central Processing Unit) 10 and its CPU 10
ROM (Read Only Memory) 11 and RAM (Random
Access memory) 12, interface 13, and A / D current proportional to the vehicle speed output from chassis dynamo 2
A / D converter 15 for converting and A / D converter for A / D converting the sound pressure level signal output from each sound level meter 16/18 into a noise value signal
It is basically composed of 17 and 19 and is connected as shown.

In the ROM 11, each sound collection microphone M _{1 to} M ₁₆ and N _{1 to} N
Set the distance from the ₁₆ reference positions for each sound collection microphone M _{1 to} M ₁₆
・ A table corresponding to N _{1 to} N ₁₆ , a control program for switching control for switching the channel selectors 4 and 5 as described later, and a control program for storing the noise data of the measurement result in the memory or printing it in the printing mechanism. Are stored in advance.

The RAM 12 is provided with a general memory such as a memory for temporarily storing the calculation result of the CPU 10 and a memory for storing the noise data.

Next, the sound collecting microphones M _{1 to} M performed by the control device C.
A flow chart of the switching control for sequentially switching ₁₆ · N _{1 to} N ₁₆ will be described with reference to FIG.

The switching control of the sound collecting microphones M _{1 to} M _{16 is the same as} the switching control of the sound collecting microphones N _{1 to} N ₁₆ , and the switching control for switching the sound collecting microphones M _{1 to} M ₁₆ will be described.

When the engine of the automobile 1 is started and the start signal is received, this control is started, the process proceeds to step S1 (hereinafter simply referred to as S1 and other steps are handled similarly), the initialization is executed, and the process proceeds to S2.

At S2, it is determined whether or not the vehicle speed is 50 km / H based on the vehicle speed signal generated by the chassis dynamo 2 and input through the A / D converter 15, and when the vehicle speed is not 50 km / H, S2 is repeated. When it reaches 50km / H, it shifts to S3.

In S3, it is determined whether or not the throttle is fully opened based on the throttle opening signal. When the throttle is fully opened, the process proceeds to S4. The time when the throttle is fully opened as described above is the reference time.

In S4, the counter I is cleared, and in the next S5, 1 is added to the counter I.

In the next S6, collected microphones M ₁ ~M ₁₆ with the same number as the counter value of the counter I is selected.

For example, immediately after the start of control, the counter value of the Kaukata I is 1, so the sound collection microphone M ₁ is selected. In this case, the CPU 10 outputs a control signal for selecting the sound collecting microphone M ₁ to the channel selector 4 via the interface 13.

In the next S7, the sound collection microphones selected in S6 M ₁ ~
The noise value signal of the automobile 1 is read through the M ₁₆ , the channel selector 4, the sound level meter 16 and the A / D converter 17, and the noise value is printed by the printer in the next S8.

Next, in S9, the vehicle speed signal V is output from the chassis dynamo 2.
(T) is read, and in the next S10, the vehicle speed signal V
Based on (t), the traveling distance S (t) of the automobile 1 from the reference time point is obtained by the following integral calculation.

In the next S11, it is determined whether or not the counter value of the counter I is 16, and when it is not 16, the process proceeds to S12.

In S12, the travel distance S (t) and the distance X (I) about the table data from the reference position of the M ₂ ~M ₁₆ (sound collection microphone located one behind) next collected microphones which is calculated in S10 Based on the travel distance S from the reference time point
(T) is either the distance X (I + I) whether from a reference position of the next sound collection microphone position M ₂ ~M ₁₆ is determined, when it does not reach the next sound collection microphone position M ₂ ~M ₁₆ is, S6 ~ S
12 is repeated at every minute time, and when it reaches M _{2 to} M ₁₆ at the next sound collecting microphone position, the process proceeds to S 5.

Then, S5～S12 is switched sequentially collected microphones M ₂ ~M ₁₆ is repeated for each minute time, the counter I is 16, that is, switched to 16 th collected microphones, Y in S11
It is determined to be es and this control ends. It is needless to say that the right microphone N _i (i = 1 to 16) is measured in parallel with the left microphone M _i (i = 1 to 16).

As explained above, a plurality of sound collecting microphones M _{1 to} M ₁₆ and N _{1 to} N ₁₆ are sequentially switched by a relatively simple device.
Noise can be measured by a method corresponding to the O362 full-open acceleration driving test method, and the noise data can be printed out.

In this embodiment, 16 sound pickup microphones M ₁ to
Although M ₁₆ is arranged at a predetermined interval, it goes without saying that the number of the sound collecting microphones and the interval thereof can be freely set.

Although the vehicle speed signal is input from the chassis dynamo in this embodiment, it may be input from the vehicle speed sensor of the automobile 1.

[Brief description of drawings]

1 to 3 show an embodiment of the present invention. FIG. 1 is a schematic plan view of a noise measuring device for an automobile, FIG. 2 is a block diagram of the noise measuring device, and FIG. A flow chart of the routine, FIG. 4 is an explanatory view for explaining the fully open acceleration running test method specified in ISO362. 1 ... Car, 2 ... Chassis Dynamo, 2a ... Laura,
4.5 Channel selector, 10 CPU (central processing unit), 11 ROM (read only memory), 12RAM
(Random access memory), 15/17/19 …… A / D
Transducer, 16 ・ 18 …… Sound level meter, M _{1 to} M ₁₆・ N _{1 to} N ₁₆ …… Sound collection microphone, C …… Control device.

Claims (1)

[Claims] 1. A vehicle noise measuring device in which driving wheels of an automobile are mounted on a roller of a chassis dynamometer, and noise generated when the automobile is driven is measured through a sound collecting microphone and a sound level meter. The sound collecting microphones are arranged side by side in the vehicle at appropriate intervals in the front-rear direction, a vehicle speed signal is received from at least one of the chassis dynamo and the vehicle, the traveling distance is calculated from this vehicle speed signal, and the traveling distance is corresponded to A noise measuring device for an automobile, which is provided with a switching device for selectively switching the sound collecting microphones in sequence.