Research on Intake Noise Control of Truck Idle Air Compressor Wang Liang Luo Hong Qi Zhigang Wang Weidong 1. College of Mechanical Engineering, Chongqing University, Chongqing 40003, 2 Dongfeng Commercial Vehicle Technology Center, Shiyan 442000, Hubei, China Designed an expanded muffler and an interferometric muffler. Acoustic finite element analysis of the intake system of the intake manifold and air filter of the air intake manifold of the air compressor of the intake muffler shows that the sound transmission loss of the designed muffler is significant. On this basis, the prototypes were prototyped for the expanded muffler and the interferometric muffler and the actual vehicle noise reduction effect was verified. As a result, the design muffler can effectively reduce noise and the interference muffler is better than the expansion muffler. Due to the structural weakness of the designed interfering muffler and the characteristics of the air compressor and the engine shared air intake system, the interferometric muffler was engineered and improved. The acoustic finite element sound transmission loss and the real vehicle noise reduction effect of the engineered interferometric muffler are still significant. Although the muffling effect of the interfering muffler is slightly worse than that of the interfering muffler, it avoids the shortcomings of long pipe length. Finally, the gas cylinder boost test was carried out on the engineering design of the interfering muffler. Although the boosting time was slightly increased, it was far superior to the national standard.

Air brakes are used in medium-sized trucks. The air pressure side shares the intake system with the engine. As the air compressor piston machine as its main energy supply device is arranged in the up and down movement of the engine cylinder head and the periodic opening and closing of the engine intake valve, in the air compressor received date 20090713 modified date 2009 car 1 recognize 0 and car vibration The noise is controlled by the noise intake of the intake manifold and the engine intake pipe to radiate noise. The truck studied in this paper has obvious beep noise when idle. The sound intensity surface noise source identifies that the surface noise radiation source is the air inlet and the air filter, respectively, and the intake system noise is formed. The fundamental original reading of noise radiation 2. The noise spectrum of the vehicle is set at idle speed and the noise spectrum measured by the air compressor is cut off by the transport method. Comparing the two spectra can determine that the abnormal noise is the intake noise caused by the air intake pulsation and the frequency range is 2701330, because the air filter has been well entangled with the engine. In order not to change the control effect of the air filter on the engine noise. This paper only designs and tests the compressor air intake muffler for the noise in this frequency band.

The intake muffler is selected and initially designed into a muffler-like muffler. The reason is that the resistive muffler is mostly a ship cotton material. 1. It is unfavorable to the intake air after aging; the resistive muffler has a remarkable effect on the middle and high frequency noise elimination, and the resistance muffler is effective for the middle and low frequency sound elimination. The noise input is to be low-frequency noise, so this paper sets a resistance eliminator for noise control.

Commonly used resistance elimination device, expansion type eliminator vibration type consumer and interference muffler. The resonant muffler can effectively control the noise of low-frequency noise. 3 However, the cost of noise reduction is high, and the original air-to-air intake pipe is small, and the processing method of the resonance muffler sample is poor. Therefore, only the design of the expansion and interference muffler is carried out in this paper.

The design of the expanded muffler is to use the acoustic impedance tipping caused by the sudden change of the section to reflect the sound, and the incident sound wave reflects the Lubo and cancels each other to eliminate the sound. The middle cavity expansion muffler disappears! 1 is the length of the expansion cavity where 〃 is the expansion ratio. 38217 peak frequency is. Therefore, 30012 is selected as the peak of the expansion muffler. From the formula 1, the length of the expansion chamber is =, = the diameter of the original air compressor intake pipe is 22, considering the noise reduction performance and the assembly space of the muffler, the diameter of the expansion chamber is 80. The expansion ratio of the single cavity expansion muffler is The design of the 12-interference muffler is that the interfering muffler divides the sound waves of the same frequency into several paths. Because the length of each bamboo road is not the same, the sound waves transmitted from the respective channels of the confluence 6 are opposite in phase, thereby interfering with the noise cancellation. 2 According to the principle of interference noise elimination, the intake pipe 2 of the fixed length of the air compressor inlet pipe 2 is connected in parallel with the air compressor of the original air compressor and the intake pipe of the engine. Thus, when the intake pipe similarity is half a wavelength, the sound waves interfere with the sound elimination due to the opposite phase after the engine intake pipe merges.

Gang 2 Ding-style muffler set! The selection of the muffling peak frequency is 3004 and the sound velocity in the tube is 34, 15 mountains. = Enter, get. In =, so, the wavelength into = 340 + 300 claws, half a wavelength is 056,667. The original air compressor intake bamboo length is 205, Shao Mo new installed air intake bamboo you set to 77L67mm.

2 Acoustic finite element analysis to study the acoustic finite element simulation of the singular resistance muffler 消卢忭 can meet the engineering requirements. In order to simulate the muffling characteristics of the air intake system after installing the muffler, based on the calculation of the acoustic finite element transmission loss of the design muffler, the intake system including the air intake pipe and the air filter of the air compressor intake manifold of the design muffler was carried out. Acoustic finite element analysis. Jade 4 is used to install the expansion muffler and the interfering muffler air intake system. This article simplifies the effects of engine cylinders and intake manifolds. To ensure the accuracy of the analysis. When dividing the finite grid, the unit size is the best to satisfy the acoustics. The wavelength specified by Cn.inK=j2n 1 must be six cents. The highest analysis frequency of the 1st iX is 5667. Since the idle noise of the cargo is 270,3302, the acoustic analysis software 501 is used to calculate the noise of the intake system. At the same time, the muffler's muffling amount is at the peak frequency, and the pressure distribution is obvious. In the simulation, when the air compressor inlet is set to a unit and the noise spectrum of the original vehicle is compared, the noise peaks of 270 12, 33012 are significantly reduced after the muffler is installed. After installing the expansion muffler and the interferometric muffler. The noise in the 270z3301 frequency range that caused the idling noise dropped from 7618 yeah to 5794 and 55.37. The noise of the 25216001 van has dropped by 632 books and 64,348 people respectively. The interfering muffler is superior to the expansion muffler in the effect of the vehicle idling noise and the road analysis frequency band noise.

4 Interferometric muffler engineering design For the design of the interfering muffler, the length of the bamboo in the intake bamboo is too long and causes a certain bending. It is easy to cause helium, which seriously affects the efficiency of inflation and driving safety. The ten-air press and the launching of the iblishingHouse.Allrightsreserved, http 3 test verification and control effect evaluation acoustic finite element analysis results show that the designed muffler has better muffling characteristics. On this basis, a prototype of a muffler was made and a verification test was performed on the actual vehicle. Test the wave of the hook 1 The measurement of the idle noise caused the whole vehicle to be set to idle speed, and the 615 channel vibration and noise analysis system was adopted. During the measurement, the microphone is placed between the 5 compartments of the factory cab. If the front end 19 is away from the ground 15, the front end 19 is called the training body position and points vertically to the steam side.

It can be seen from 5 that the interference muffler has better noise cancellation effect on the target frequency than the expansion muffler. The installation of the expanded muffler has the largest sound loss near the frequency of 3001, adding about 23 701 and the interfering muffler adding about 35 rpm. The frequency band in which the expansion muffler is installed has a larger frequency band, and the frequency band of the interfering muffler has a narrower frequency band, which has a stronger frequency selectivity, but still meets the design requirements.

Pressure, intake system inlets set full sound absorption conditions. The sound pressure at two points of the air inlet of the air compressor is calculated to obtain the incident sound pressure of the system, and the sound pressure of the air intake system is extracted from the air intake system of the inlet system to obtain the sound loss of the air intake system, which is small.

Or when the intake manifold size becomes larger, the noise reduction effect will be worse.

Acoustic finite element analysis and real vehicle verification test of the sample were carried out on the engineering design of the interfering muffler. 9 is the contrast curve of the transmission loss. It can be seen from the cabinet 9 that the transmission loss of the interferometric muffler and the engineered design is equivalent to around 3001. 10 is the noise spectrum measured after installing the sample of the Shiyan-style banter. Installation of the interferometric shoal 1 design 1 27013301 range of noise dropped to 6158 This 425600 range of noise dropped 512 recognition. Compared with the spectrum of the noon muffler and the interferometric muffler installed in the noon noise spectrum, the noise reduction of the engineered design is slightly lower, but the noise reduction effect is still obvious. The engineering design is superior to the expansion type in terms of noise reduction cost and layout requirements, and avoids the shortcomings of the interference muffler pipeline. It is stated that the size of the engine intake manifold relative to the noise reduction target frequency still satisfies the plane wave theory. When the standard frequency word. Higher, the 19942012 ChinaAcademicJoumalElectronic machine shared a helium system, and the gas continued to flow into the intake manifold after entering the engine intake pipe from the air compressor intake pipe. Thus, the air from the intake pipe into the engine air pipe is designed to be separated from the forward flow, and then merged with the air flow from the intake pipe. The two airflows are opposite in phase, and the sound is 8 left. That is, the 4 pieces + 4; = 05 interference interference. Considering the factors such as the spatial arrangement of the charging efficiency and the noise reduction cost, the value is 250. The degree of the pipeline is only 52167.8 from the original Le machine, and the engineering design is a real vehicle sample.

In order to verify the impact of the installation of the engineered interfering muffler on the braking performance of the vehicle, according to the structural performance and test method of the 0526761999 automobile brake system, the air pump boost time measurement was carried out. The results show that under the rated engine speed, after the original car and the installation of the engineered interfering muffler, the gas cylinder is boosted to the factory constant pressure for 6 times, respectively, 100, 1 and 105, and the pressure is raised to the factory constant pressure time of 20, 1 and 215 respectively. Yuanyou 31 and 6, the national standard limit requirements.

5 Conclusions include air compressor design muffler air filter air compressor air intake pipe and engine intake pipe intake system acoustic limited å…€ sound loss. The household muffler and the industrialized design have the same sound loss in 270 3301, and are superior to the expanded muffler.

The actual vehicle noise reduction effect of the air compressor intake muffler is 5 ä½¥ proof. The noise control effect is remarkable. The noise reduction effect of the interferometric muffler is better than that of the expansion muffler. Although the engineering design is less effective than the interference canceler and the expansion muffler, the noise reduction cost is low and the profit is low. Moreover, the disadvantage that the interfering muffler pipe is long only helium is avoided.

The gas cylinder boost test was carried out on the 1-stage design of the interfering muffler. Although the boosting time was slightly increased, it was far superior to the national standard.

He Yusheng, and so on. Car noise control. Beijing Machinery Industry Publishing Qi Zhigang, Deng Zhaoxiang, Wang Liang, and so on. Medium-duty trucks idling noise source, knife. Vibration and shock. 2,2831771 Yang Cheng, Deng Zhaoxiang, Yan Dengfang, and so on. Analysis of the mechanism of intake noise and Huang Zisi, Jiang Weikang, Zhu Yuli, et al. Numerical analysis and experimental study of compressor muffler characteristics. Journal of Vibration Engineering, 2004, 174399402 Engineering Design of Thousand-speaker Muffler

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