KR20040037776A - System for measuring transmission loss for intake and exhaust system in vehicles - Google Patents

Abstract

PURPOSE: A measurement system for measuring the transmission loss in an intake/exhaust system of a vehicle is provided to optimize a loss reduction characteristic by precisely measuring the transmission loss in the intake/exhaust system. CONSTITUTION: A measurement system for measuring the transmission loss in an intake/exhaust system includes a muffler(10), a connection member(20) connected to the muffler(10), a microphone(30) installed on the connection member(20) so as to measure sound pressure, and a speaker(40) installed at one end of the connection member(20) in order to generate acoustic energy. A noise generator(60) is provided to generate a vibration signal for allowing the speaker(30) to generate acoustic energy. A terminator(50) is installed at the other end of the connection member(20) so as to reduce a reflective wave towards the muffler(10).

Description

Transmission loss measurement system of vehicle {SYSTEM FOR MEASURING TRANSMISSION LOSS FOR INTAKE AND EXHAUST SYSTEM IN VEHICLES}

The present invention relates to a system for measuring transmission loss of an intake and exhaust system of a vehicle. More specifically, the present invention relates to an intake system and an exhaust system mounted on a vehicle. The present invention relates to a vehicle intake and exhaust loss measurement system for establishing an effective intake and exhaust ventilation design measure.

Conventionally, after developing various prototypes in the development of intake and exhaust, the relative evaluation of each was carried out in the actual vehicle state.

However, it is difficult to measure the transmission loss for each frequency by measuring the output noise emitted by the engine input. In addition, it is difficult to mount the initial evaluation product due to the actual vehicle mounting, and it is difficult to grasp the characteristics of the intake system due to data including the influence of other parts, such as an air cleaner or an exhaust system catalyst.

And when evaluating the unit, a speaker is installed at the input terminal, and a microphone is installed at the input / output unit.

However, the noise measured at the input terminal is a noise including both the input noise and the reflected noise, and data errors due to the influence of the reflected noise are severely generated.

In addition, since the output noise is not restrained at the output terminal, the data error of the output noise of the discharge port is severe, and there is no device for terminating the noise, thereby being affected by the reflected noise.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a delivery loss measuring system of a vehicle for optimizing loss reduction characteristics by measuring accurate transmission loss of an intake and exhaust machine.

1 is a view schematically showing the configuration of a transmission loss measuring system of a vehicle in accordance with the present invention.

<Description of the symbols for the main parts of the drawings>

10. EUT

20. Connecting member

30. Microphone

40. Speaker

50. Terminator

60. Noise Generator

70. Program

80. Analysis System

Intake and exhaust system transmission loss measurement system of the vehicle of the present invention for achieving the above object, the silencer to be tested; A connection member connected to the silencer; A microphone installed on the connecting member for measuring the sound pressure transmitted to evaluate the transmission loss of the muffler; A speaker installed at one end of the connection member to generate acoustic energy; A noise generator for giving an excitation signal for generating acoustic energy from the speaker; A terminator installed at the other end of the connection member to increase the degree of measurement by minimizing the reflected wave toward the silencer with respect to the sound passing through the silencer outlet; A program connected to the microphone, for calculating sound pressure and correlation with the measured data, and calculating transmission loss and noise reduction; And an analysis system that calculates a transmission loss through the sound pressure measured from the microphone.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram schematically showing the configuration of the intake and exhaust system transmission loss measurement system of a vehicle according to the present invention.

Referring to the drawings, intake and exhaust system transmission loss measurement system of the vehicle according to the present invention, the muffler (muffler) which is the test object 10 to be tested, the connecting member 20 connected to the muffler, and the transmission loss of the silencer In order to measure the sound pressure transmitted to evaluate the microphone 30 (microphone) (30) installed in the connecting member 20, and a speaker installed at one end of the connecting member 20 to generate sound energy (speaker) 40, a noise generator 60 which gives an excitation signal for generating acoustic energy from the speaker 40, and the other end of the connection member 20, which is passed through the silencer outlet. It is connected to the terminator (50) and the microphone (30) and (40) to increase the degree of measurement by minimizing the reflected wave toward the silencer with respect to the sound, and the auto power and correlation cross power (FRF), Programmer 70 for calculating transfer loss and noise reduction, and analyzer 80 for calculating transfer loss through auto power and cross power measured from microphones 30 and 40. It is configured to include).

The noise generator 60 has a different frequency depending on the measurement purpose, but in order to measure the sound absorption performance of the silencer, a white noise of 20 to 20 KHz is set.

In addition, two microphones 30 and 40 are installed at each end of the connecting member 20 to separate incident and reflected waves.

In addition, a sound absorbing material 51 is installed inside the terminator 50, and the analysis system 80 is composed of an A / D converter for converting a digital signal and a computer.

And the speaker 40 is made of a completely sound-absorbing hermetic other than the sound output of the front end.

In particular, the program 70 is comprised of CADA-X SW (software) for calculating sound pressure and correlation with measured data, and UPA language for calculating transmission loss and noise reduction.

Referring to the operation of the transmission loss measurement system of the vehicle according to the present invention having the configuration as described above is as follows.

First of all, in order to minimize reflection noise and noise in the measurement of transmission loss, a test should be conducted in an anechoic chamber. Then, the speaker 40 and the terminator 50 are installed at the input and output terminals of the intake or exhaust system to be measured, and the connection to the silencer is sealed as much as possible.

In addition, after performing the calibration of the microphones 30 and 40, each of the two microphones 30 and 40 is inserted into the input and output terminals of the muffler to minimize the difference between the impedances of the microphones 30 and 40. To make the diameter of the same, the insertion amount of the microphone 30, 40 is minimized.

Then, the distance between the two microphones 30 and 40 is measured, the speaker 40 and the noise regenerator are connected, and the frequency of the noise regenerator is set to 20 Hz to 20 KHz to generate white noise.

Subsequently, autopower and crosspower for the sound passing through the input stage and FRF between the microphones 30 and 40 are measured.

After the measurement, the FRT is measured by changing the positions of both microphones 30 and 40, and the measurement time is averaged at least 50 times.

The measured transmission loss is then set in the direction of improvement.

When the transmission loss is obtained from the incident wave at the input terminal and the incident wave at the output terminal is obtained in the same manner, the transmission loss (TL) can be obtained as shown in Equation 1 below.

As described above, the intake and exhaust system transmission loss measuring system of the vehicle according to the present invention has the following effects.

Accurate transmission loss of the intake and exhaust machine can be measured to optimize loss reduction characteristics. In addition, the development period and the number of specimens resulting from the actual vehicle test and the incorrect test can be reduced.

In addition, parts can be simplified according to the internal structure of the optimum intake and exhaust machine for noise reduction.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent embodiments are possible. Therefore, the true scope of protection of the present invention should be defined only by the appended claims.

Claims (5)

A silencer to be tested; A connection member connected to the silencer; A microphone installed on the connecting member for measuring the sound pressure transmitted to evaluate the transmission loss of the muffler; A speaker installed at one end of the connection member to generate acoustic energy; A noise generator for giving an excitation signal for generating acoustic energy from the speaker; A terminator installed at the other end of the connection member to increase the degree of measurement by minimizing the reflected wave toward the silencer with respect to the sound passing through the silencer outlet; A program connected to the microphone, for calculating sound pressure and correlation with the measured data, and calculating transmission loss and noise reduction; Analysis system for calculating the transmission loss through the sound pressure measured from the microphone; Delivery loss measuring system of a vehicle comprising a. The method of claim 1, The noise generator is configured to set the white noise of 20 ~ 20KHz in order to measure the sound absorption performance of the muffler, the transmission loss measuring system of the vehicle. The method of claim 1, And two microphones at each end of the microphone to separate incident and reflected waves from the connecting member. The method of claim 1, Absorption machine transmission loss measurement system of a vehicle, characterized in that the sound absorbing material is installed inside the terminator. The method of claim 1, The analysis system comprises an A / D converter for converting into a digital signal, and a computer intake exhaust loss measurement system, characterized in that the computer.