JP2001099703A - Equipment sound simulation method and equipment sound simulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize an equipment sound simulation method capable of estimating a tone quality of an operation sound generated at an operation time of driving equipment by simulation based on surface vibration of the driving equipment, and an equipment sound simulator by the simulation method. SOLUTION: Surface vibration of an engine is calculated by taking into consideration data exerting an influence on a tone quality of the engine. A sound pressure spectrum at an optional point is calculated by a boundary element method, based on the surface vibration of the engine, and a time series waveform of the sound pressure is obtained by executing inverse Fourier transformation of the sound pressure spectrum. In this simulation method, an equipment sound is simulated by displaying the time series waveform on a CRT or by reproducing it by an imaginary sound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of simulating engine sounds of a construction machine or the like and a simulator for executing the method.

[0002]

2. Description of the Related Art Various researches and developments have been made on noise reduction of prime movers such as forklifts and construction machines. In recent years, not only low noise but also good sound quality such as "powerful" and "comfortable" has been required. In particular, from the viewpoint of the user, when the noise levels are equal, good sound quality is important, and the ratio of sound quality in engine evaluation tends to increase.

[0003] Conventional sound quality improvement of an engine sound is performed in a series of steps such as sound quality evaluation of a recorded engine sound → design change → prototype production → confirmation / examination of the sound quality of a prototype. The outline of each process is as follows.

[0004] Sound quality evaluation is roughly classified into subjective evaluation and objective evaluation. Subjective evaluation is the human ear (sensuality)
Is used to subjectively evaluate the quality of the sound quality. For example, SD (Semantic D)
There is an differential method. On the other hand, objective evaluation means, for example, Zwicker loudness level analysis, etc.
The evaluation is based on the correlation analysis of physical parameters.

[0005] The design change is a process of estimating a structural change point of the engine based on the result of the sound quality evaluation and performing a design change.

[0006] Prototype production is a process of preparing a prototype based on the above modified design, and confirming and examining the sound quality of the engine modified by the prototype.

[0007] Usually, the improvement work by the above-mentioned procedure is not limited to one time, and the above-mentioned improvement work is repeated for a prototype, and the sound quality is improved by trial and error.

[0008]

However, according to a series of conventional sound quality improvement techniques, it is necessary to confirm and study an engine that has repeatedly produced a prototype, which requires a considerable amount of time and effort. Further, such a trial-and-error method requires the production of a prototype many times, and the cost required for research and development is also large.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is a device sound simulation in which a changed engine sound quality can be easily confirmed and examined by simulation without actually producing a prototype many times. It is an object of the present invention to realize a device sound simulator by the method and the simulation method.

[0010]

According to a first aspect of the present invention, there is provided a sound pressure spectrum calculating step of calculating a sound pressure spectrum at an arbitrary position based on a surface vibration of a prime mover by a boundary element method; From the result, a waveform calculation step of calculating a time-series waveform of the sound pressure at the arbitrary position,
Displaying a time-series waveform of the sound pressure.

According to a second aspect of the present invention, in the first aspect, the method further comprises a virtual sound reproducing step of reproducing a virtual sound when the driving apparatus is operating, based on the time-series waveform of the sound pressure. The method according to claim 1, wherein

According to a third aspect of the present invention, there is provided a surface vibration analyzing means for analyzing a surface vibration of a prime mover, and a sound pressure spectrum calculating means for calculating a sound pressure spectrum at an arbitrary position by a boundary element method based on the analysis result. Comprising, from the sound pressure spectrum calculation result, a waveform calculating means for calculating a time-series waveform of sound pressure at an arbitrary position of the prime mover, and a display means for displaying a time-series waveform of the sound pressure. This is a featured equipment sound simulator.

According to a fourth aspect of the present invention, in the third aspect, a virtual sound reproducing means for reproducing a virtual sound during operation of the driving apparatus based on the time series waveform of the sound pressure is further provided. An apparatus sound simulator according to claim 3.

In a fifth aspect based on the third aspect, the surface vibration analysis means analyzes the surface vibration by a finite element method and a vibration analysis based on characteristics of parts constituting a driving apparatus. This is a featured equipment sound simulator.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First to fourth embodiments of the present invention will be described with reference to the drawings.

Hereinafter, an engine will be described as a prime mover, and a simulation method for improving the sound quality of the engine and a simulator using the method will be described.

(First Embodiment) FIG. 1 is a diagram for explaining a schematic configuration of a device sound simulator 1 according to a first embodiment.

The functional configuration of the equipment sound simulator 1 is roughly classified into an engine data storage unit 10 for storing data (physical quantities) relating to an engine which is considered to affect the engine sound quality as parameters used for analyzing the vibration of the engine surface described later. A sound pressure waveform analysis unit 20 that analyzes the surface vibration of the engine based on the data on the engine and calculates a time-series waveform of the sound pressure at an arbitrary position according to a calculation method described later. The calculated sound pressure waveform can be displayed, and the output unit 30 can be divided into three configurations of the output unit 30 that generates and reproduces a virtual sound of the engine based on the waveform.

First, a schematic configuration of the engine data storage unit 10 will be described.

The data stored in the engine data storage unit 10 affects the surface vibration of the engine.
This is a physical quantity that also affects engine sound quality. The storage unit 10 according to the present embodiment stores parameters calculated from actual measurement data during operation of an engine to be analyzed and characteristic data such as the shape and physical properties of an engine block and a crankshaft. .

The actually measured data is measured data indicating a force or the like received from a heat medium when the engine operates as an internal combustion engine, and includes, for example, an in-cylinder pressure of a cylinder and an injection pressure of an injection pump. In the first embodiment, only the in-cylinder pressure 101 is considered. The characteristic data is
Related to the specific structure and physical properties, such as material, shape,
It affects the natural vibration and the equation of motion, such as stiffness and damping. In this embodiment, the finite element method (FEM: Finite) is used as characteristic data from the shape and characteristics of the engine block (crankcase, cylinder head, front plate, gear case, injection pump, oil pan, etc.).
Element block natural vibration characteristics 107 obtained by the element method, the first shaft natural vibration characteristics 111 similarly calculated by the finite element method from the shape of the crankshaft, and the rigidity / damping 115 of the case support and the bearing.
And a liner natural vibration characteristic 103, and a piston slap force 105 calculated from the liner natural vibration characteristic 103 and the in-cylinder pressure 101 are stored.

Next, the schematic configuration of the sound pressure waveform analyzer 20 will be described. The sound pressure waveform analyzer 20 includes a surface vibration analyzer 201, a sound pressure spectrum calculator 203, and a sound pressure time-series waveform calculator 205.

The surface vibration analysis unit 201 reads out the actual measurement data and various characteristic data stored in the engine data storage unit 10 and reads the data between the engine block and various shafts (in the first embodiment, only the crankshaft). And modal response is calculated.

The surface vibration response of the engine is expressed as shown in equation (1) using the natural mode and the modal response.

[0025]

(Equation 1)

That is, the sound pressure spectrum calculator 203
Is a boundary element method (hereinafter referred to as BEM: Bou) based on the surface vibration of the engine calculated by the surface vibration analysis unit 201.
ndary Element Method), a sound pressure spectrum at an arbitrary observation point is calculated. The outline of the calculation by the boundary element method executed by the sound pressure spectrum calculation unit 2034 is as follows.

FIG. 2A shows a surface of an engine to be analyzed by a closed surface S in a three-dimensional Euclidean space. Point m is a coordinate point on the closed surface.

In general, it is well known that the sound pressure at an arbitrary point 1 in the flat curved surface S of the three-dimensional sound field shown in FIG. 2A can be obtained by the following boundary integral equation (2). It is being done.

[0029]

(Equation 2)

However, the integration is performed over the closed surface S.

If pm and pm / n on the boundary surface are obtained from equation (2), k and _rlm are known, so that the sound pressure at an arbitrary point 1 can be calculated.

Here, generally, the following relationship (3) is established between the gradient of the sound pressure spectrum and the response acceleration vector.

[0033]

(Equation 3)

Since the response acceleration vector is represented by the natural vibration mode and the modal response by the modal response calculation unit 202, pm / n in equation (2) can be known.

In the equation (2), after all, the first
Only the term pm is unknown. In the present invention, FIG.
As shown in (1), the boundary surface (engine surface, that is, the closed surface S) is discretized into k boundary elements, and the unknown pm is calculated by the boundary element method. In the boundary element method, k equations can be described by setting 1 point on a small element m on the boundary. Since the unknown number pm is also k, the value of pm can be calculated by solving the k simultaneous equations.

Therefore, by using the equations (2) and (3), it is possible to calculate the sound pressure at an arbitrary point l. However, the calculated sound pressure is a value when focusing on a certain frequency, and can be calculated for any frequency by changing the focused frequency.

The sound pressure time series waveform calculation section 205 performs an inverse Fourier analysis on the sound pressure spectrum calculated by the sound pressure spectrum calculation section 203 to calculate a temporal waveform of the sound pressure. That is, since the sound pressure spectrum is a Fourier integral with respect to time, a time-series waveform can be obtained by inversely transforming the Fourier integral.

Next, the configuration of the output unit 30 will be described.

The output unit 30 is an output unit that outputs the result of the calculation performed by the sound pressure waveform analysis unit 20, and includes a CRT, a speaker, and the like. When viewing the time series waveform of the sound pressure by the above calculation, the waveform is displayed on a CRT.
Further, the virtual sound having the waveform can be output by a speaker. In this case, a photograph or the like of the engine to be analyzed is displayed on the CRT, and a desired position around the engine is designated by an input device such as a mouse, so that the engine sound observed at the position is reproduced. There may be.

An example of a simulation result by the simulator configured as described above is shown below. Note that the modal response condition is calculated in steps of 1.0 × 10 ⁻⁶ sec.
The output increment was 1 deg. The calculation conditions of the boundary element method executed in the sound pressure spectrum calculation unit 203 are as follows:
The frequency step was 18.3 Hz.

The time series waveform of the sound pressure and the waveform of the sound pressure spectrum obtained by executing the calculation for the above model are shown in FIGS. 3 and 4. FIG. The waveform shown in FIG.
m point (FIG. 4A), 1 m point on the left side of the engine (FIG.
(B)), set at 1 m point on the right side of the engine (FIG. 4 (c)).

Finally, a description will be given of a method for designing a sound-quality engine using the above-described device sound simulator 1.

First, a desired desirable engine sound (hereinafter, target sound) is determined. This can be obtained, for example, by electrically changing the recorded engine sound.

Next, a change in the engine structure or the like (for example, a change to another injection pump or crankshaft having a different shape, etc.)
The engine sound after the structural change is simulated by the equipment sound simulator 1.

Next, the engine sound estimated by the simulation and the target sound are compared and evaluated. This evaluation may be a subjective evaluation by hearing or an objective evaluation by correlation analysis of physical parameters. If the sound quality is insufficient according to the evaluation, the engine structure and the like are further changed, and this is repeated until the sound quality is sufficient.

Finally, an engine having a structure or the like having a sufficient sound quality in the above simulation is actually produced on a trial basis, and the final evaluation is performed, whereby an engine with preferable sound quality can be designed.

According to the configuration described above, if the surface vibration of the engine is known, the time-series waveform of the sound pressure at an arbitrary position can be known, so that the desired position can be obtained at a desired position without making a prototype. Sound quality can be simulated. this is,
In particular, it is effective for knowing a change in sound quality that occurs when a part is changed. As a result, it is possible to improve the workability of research and development and reduce costs.

(Second Embodiment) In the second embodiment, an example of a simulation in which the injection pressure of the injection pump and the data of the gear system are further added as data to be considered in the engine surface vibration analysis will be described.

That is, in the second embodiment, the in-cylinder pressure 101 and the injection pressure 1
17 also includes, as characteristic data, an engine block natural vibration characteristic 107 obtained by a finite element method from the shape of the engine block (crankcase, cylinder head, front plate, gear case, injection pump, oil pan, etc.); , The piston slap force 105 calculated from the liner natural vibration characteristic 103 and the in-cylinder pressure 101, the shape 119 of the injection pump cam, and the shape of the injection pump cam 119 and the injection pressure 117. Injection pressure side force 121
Second shaft natural vibration characteristic 123 calculated from the shapes of the crankshaft, the injection pump camshaft, and the intermediate shaft by the finite element method
And rigidity / damping 125 of case support, bearings, gears, etc.
And the gear shape 127 of the crankshaft, the injection pump camshaft, and the intermediate shaft are stored in the engine data storage unit 10.

Based on these data, the surface vibration analysis unit 201 couples the engine block, various shafts (crank shaft, intermediate shaft, injection pump cam shaft in the second embodiment) and the gear system. Calculate the vibration. By performing analysis in the same procedure, a sound pressure spectrum, a time-series waveform of sound pressure, and a virtual sound during operation can be obtained.

In the second embodiment, since the gear shape 127 is taken into account as the characteristic data, a simulation in which the backlash of the gear is taken into account is also possible. FIGS. 6 and 7 show a sound pressure spectrum and a time series waveform of sound pressure in consideration of the backlash (for example, ± 40 μm) of the gear in addition to the above data.

In the auditory experiment conducted by the inventors, it was confirmed that the simulation in which the backlash of the gears was taken into consideration reproduced sound more realistic than the case where the backlash was not taken into consideration.

(Third Embodiment) In a third embodiment, an example of a simulation in which data concerning a valve train and a gear train are added as data to be considered in the engine surface vibration analysis will be described.

The case where the data stored in the engine data storage unit 10 has the contents shown in FIG. 8 will be described.

That is, in the third embodiment, the in-cylinder pressure 101 is measured as measured data, and the shape and characteristics of the engine block (crankcase, cylinder head, front plate, gear case,
(Injection pump, oil pan, etc.) by the finite element method, the engine block natural vibration characteristic 107, the liner natural vibration characteristic 103, and the liner natural vibration characteristic 1
03, the piston slap force 105 calculated from the in-cylinder pressure 101, the valve operating drive cam shape 129, the force 131 related to the valve operating system calculated from the valve operating drive shape 129, and a finite element. The third shaft natural vibration characteristic 123 calculated from the shapes of the crankshaft, the valve train driving camshaft, and the intermediate shaft by the method, rigidity / damping 125 of case support, bearings, gears, etc., the crankshaft, the valve train System drive cam shaft,
The gear shape 127 of the intermediate shaft is the engine data storage unit 1
0 is stored.

Based on these data, the surface vibration analysis unit 201 determines the relationship between the engine block, various shafts (in the third embodiment, a crankshaft, an intermediate shaft, a valve system driving camshaft) and a gear system. Is calculated. By performing analysis in the same procedure, a sound pressure spectrum, a time-series waveform of sound pressure, and a virtual sound during operation can be obtained.

(Fourth Embodiment) In the fourth embodiment,
As data to be considered in engine surface vibration analysis,
An example of a simulation when the injection pressure and data on the valve train and the gear train are added will be described.

That is, in the fourth embodiment, the in-cylinder pressure 101 and the injection pressure 1
17 and an engine block natural vibration characteristic 107 obtained by the finite element method from the shape and characteristics of the engine block (crankcase, cylinder head, front plate, gear case, injection pump, oil pan, etc.) as characteristic data. , Liner natural vibration characteristics 103
And the liner natural vibration characteristic 103 and the in-cylinder pressure 10
1, the piston slap force 105, the shape of the injection pump cam 119, and the injection pump cam 119
, The injection pressure side force 121 calculated from the injection pressure 117, the valve operating drive cam shape 129, the force 131 related to the valve operating system calculated from the valve operating drive shape 129, and finite The fourth shaft natural vibration characteristic 133 calculated from the shapes of the crankshaft, the injection pump camshaft, the valve system driving camshaft, and the intermediate shaft by the element method, the case support, the bearing,
Rigidity / damping 125 of gears, etc., and gear shapes 13 of the crankshaft, injection pump camshaft, valve train drive camshaft, and intermediate shaft
5 are stored in the engine data storage unit 10.

Based on these data, the surface vibration analysis unit 201 generates an engine block, various shafts (in the fourth embodiment, a crankshaft, an intermediate shaft, an injection pump camshaft, a camshaft for driving a valve train) and a gear. Calculate the coupled oscillations with the system.
By performing analysis in the same procedure, a sound pressure spectrum, a time-series waveform of sound pressure, and a virtual sound during operation can be obtained.

Although the present invention has been described based on the first to fourth embodiments, the present invention is not limited to the above embodiments.
For example, in the first to fourth embodiments, the finite element method is used in the surface vibration analysis of the engine, but the surface vibration analysis may be performed by another method. That is, according to the present invention, as long as the surface vibration of the engine is known, the sound pressure spectrum and the time series waveform of the sound pressure at an arbitrary position can be obtained by the sound pressure waveform analysis based on the boundary element method.

[0061]

As described above, according to the present invention, the sound pressure spectrum of the prime mover and the time-series waveform of the sound pressure are calculated by the boundary element method based on the surface vibration, so that the sound of the prime mover during the operation of the prime mover can be obtained. Can be simulated. As a result, workability in research and development can be improved and costs can be reduced.

[Brief description of the drawings]

FIG. 1 is a view for explaining a schematic configuration of a device sound simulator 1 according to a first embodiment.

FIG. 2 is a diagram illustrating an outline of a boundary element method.

FIG. 3 is a view showing a time-series waveform of a sound pressure by a simulation according to the first embodiment.

FIG. 4 is a view showing a sound pressure spectrum by a simulation according to the first embodiment;

FIG. 5 is a diagram showing an engine data storage unit 10 of the device sound simulator 1 according to the second embodiment.

FIG. 6 is a diagram showing a time-series waveform of a sound pressure by a simulation according to a second embodiment in which a backlash of a gear system is considered.

FIG. 7 is a diagram showing a sound pressure spectrum by a simulation according to a second embodiment in which a backlash of a gear system is taken into consideration.

FIG. 8 is a diagram showing an engine data storage unit 10 of a device sound simulator 1 according to a third embodiment.

FIG. 9 is a diagram showing an engine data storage unit 10 of a device sound simulator 1 according to a fourth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Equipment sound simulator 10 ... Engine data storage part 20 ... Sound pressure waveform analysis part 30 ... Output part 101 ... In-cylinder pressure 103 ... Natural vibration 103 ... Natural vibration characteristic of a liner 105 ... Piston slap force 107 ... Engine block natural vibration characteristic 111 ... first shaft natural vibration characteristic 115 ... rigidity and damping 117 ... injection pressure 119 ... injection pump cam shape 121 ... injection pressure side force 123 ... second shaft natural vibration characteristic 123 ... third shaft natural vibration characteristic 125 ... rigidity Attenuation 127: Gear shape 129: Shape of valve operating system driving cam 131: Force related to valve operating system 133: Fourth shaft natural vibration characteristic 135: Gear shape 201: Surface vibration analysis unit 203: Sound pressure spectrum calculation unit 205: Sound Pressure time series waveform calculator

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazuhide Ota 5-717-1 Fukabori-cho, Nagasaki-shi, Nagasaki Sansei Heavy Industries, Ltd. Nagasaki Research Institute (72) Inventor Susumu Katayama 3000 Tana, Tana, Sagamihara-shi, Kanagawa F-term in Mitsubishi Heavy Industries, Ltd. Sagamihara Works (reference) 2G064 AA15 AB15 DD23 DD29

Claims (5)

[Claims] 1. A sound pressure spectrum calculating step of calculating a sound pressure spectrum at an arbitrary position by a boundary element method based on a surface vibration of a prime mover, and a sound pressure spectrum at the arbitrary position from the sound pressure spectrum calculation result. A device sound simulation method, comprising: a waveform calculation step of calculating a time-series waveform of the above; and a display step of displaying a time-series waveform of the sound pressure. 2. The apparatus sound simulation method according to claim 1, further comprising a virtual sound reproduction step of reproducing a virtual sound during operation of the prime mover based on the time-series waveform of the sound pressure. . 3. A surface vibration analysis means for analyzing a surface vibration of a prime mover; a sound pressure spectrum calculation means for calculating a sound pressure spectrum at an arbitrary position by a boundary element method based on a result of the analysis; A device comprising: a waveform calculation unit configured to calculate a time-series waveform of sound pressure at an arbitrary position of the driving device from a spectrum calculation result; and a display unit configured to display a time-series waveform of the sound pressure. Sound simulator. 4. The device sound simulator according to claim 3, further comprising virtual sound reproducing means for reproducing a virtual sound when the driving device operates based on the time-series waveform of the sound pressure. 5. The surface vibration analysis means analyzes the surface vibration by a finite element method and a vibration analysis based on characteristics of components constituting a driving apparatus.
The described equipment sound simulator.