空氣濾清器外文翻譯--一個用于內(nèi)燃發(fā)動機進氣系統(tǒng)的無聲空氣濾清器的虛擬設計及性能預測

1、<p><b>　　中文3230字</b></p><p>　　一個用于內(nèi)燃發(fā)動機進氣系統(tǒng)的無聲空氣濾清器的虛擬設計及性能預測</p><p>　　HAO Zhi-yong, JIA Wei-xin, FANG Fang </p><p>　　(College of Mechanical and Energy Engineering,

2、 Zhejiang University, Hangzhou 310027, China)</p><p>　　(Tianjin Internal Combustion Engine Research Institute, Tianjin University, Tianjin 300072,China)</p><p>　　E-mail: haozy@zju.edu.cn; jiawx@

3、zju.edu.cn</p><p>　　Received Jan. 17, 2005; revision accepted May 12, 2005</p><p>　　摘要：本文報道中采用低噪聲內(nèi)燃機進氣系統(tǒng)開發(fā)的虛擬設計方法結合作者的研究結果。由此產(chǎn)生的高的通過噪聲水平高于在全油門的立法目標時，發(fā)動機轉速為5200 r/min需要邊界元輔助設計任務，按照典型的進氣系統(tǒng)的設計與開發(fā)過程

4、。在最初的設計中，基于聲學理論和要求并考慮空間發(fā)動機室中的約束，總體積和粗糙的內(nèi)部尺寸的測定。在詳細設計階段，確定了空氣濾清器的確切的內(nèi)部尺寸，和一個有效的方法應用于低頻聲性能的改善。預測表明，進氣系統(tǒng)的聲功率達到最小的進氣系統(tǒng)噪聲降低發(fā)動機整體噪聲。</p><p>　　關鍵詞：虛擬設計;聲學性能;沉默的空氣濾清器;邊界元法（BEM）</p><p><b>　　1簡介<

5、/b></p><p>　　一個原函數(shù)的進氣系統(tǒng)的主要功能是首先有效信道的新鮮空氣對發(fā)動機進氣噪聲，其次是減少排放。有一些現(xiàn)有方法的發(fā)展來提高進氣系統(tǒng)設計一個更現(xiàn)實的方法。這些目標包括：更有效的消聲性能，達到降低噪聲一方面日益嚴峻的立法目標，優(yōu)化發(fā)動機的性能和燃油經(jīng)濟性伴隨著車輛質量的提高。</p><p>　　一個典型的程序，用于汽車發(fā)動機進氣系統(tǒng)的設計與開發(fā)過程中。設計過程包括仔

6、細調諧的匹配這些發(fā)動機運行和呼吸特性的影響，污染物排放優(yōu)化影響噪聲進氣系統(tǒng)的所有組件，性能和經(jīng)濟性。從現(xiàn)有的或符號的系統(tǒng)布局，進行各種性能綜合評價。這種信息可能會被適當?shù)厥褂迷u估的各種設計目標當前系統(tǒng)的性能，通過對其構成要素進行適當修改，為系統(tǒng)優(yōu)化設計提供理論基礎。</p><p>　　邊界元法廣泛應用在進氣和排氣系統(tǒng)的設計可以用來計算內(nèi)部，外部，或兩個領域的同時，只要求的空氣濾清器可分為元素的周長；和施加邊界條

7、件的緩解是另一個吸引。在本文中，邊界元法是用來預測的空氣濾清器的傳輸損耗和噪聲排放。</p><p>　　原來的進氣系統(tǒng)設計中出現(xiàn)的水平高于在全油門和發(fā)動機轉速在5200r/min的噪聲信號的頻譜特性的立法目標噪聲高通連接通常是由離散的音調，對發(fā)動機的點火頻率是173赫茲對應5200 r/min內(nèi)聯(lián)四缸四沖程發(fā)動機諧波相關的廣泛的序列占主導地位。在許多情況下，從主源的聲能量體分布較低的頻率成分，可能是難以控制的。

8、因此，本文提到的頻率范圍是從0到1千赫。在這個頻率范圍內(nèi)，如濾紙對集成系統(tǒng)的聲學性能的影響是微不足道的，所以濾紙不顧。噪音是從空氣濾清器入口噴出，與空氣濾清器系統(tǒng)出口連接到發(fā)動機的進氣。所以在發(fā)動機空氣濾清器的出入口壓力為邊界元法的邊界條件。</p><p>　　一個降噪通常有兩部分功能的傳統(tǒng)進氣系統(tǒng)：空氣濾清消聲器。由于空間發(fā)動機室中的約束，重新設計的空氣凈化器結合清洗和沉默效果。在這項工作中，一個所謂的沉默的

9、空氣濾清器進行了重新設計，幾何結構確定的預測TL和邊界元的聲功率發(fā)射。同時，為了盡量減少在較低頻率的進氣系統(tǒng)的聲功率，旁通管被添加到空氣輸送管。所產(chǎn)生的聲學性能分析表明，該方法最大限度地減少對進氣系統(tǒng)噪聲降低發(fā)動機整體噪聲的目標是可行的。</p><p>　　2無聲空氣濾清器的設計</p><p>　　2.1原裝空氣濾清器的評價</p><p>　　這種原始的空氣濾

10、清器的清潔設計主要關注減少噪音排放?？諝鉃V清器的出口段是一個單位的速度振幅。</p><p>　　計算Tl時，空氣濾清器的出口部分給出了單元速度振幅模型的聲源，所有其他的表面被建模為“聲學硬”默認情況。出口部分的聲功率可以從公式計算。所有后續(xù)的TL的預測具有相同的邊界條件。</p><p>　　預測的空氣濾清器性能。在發(fā)動機進氣道的聲功率級是顯示圖的噪聲源信號峰值為173赫茲的頻率諧波相關

11、的發(fā)動機點火。由于發(fā)動機燃燒分布式低頻率從100赫茲到800赫茲之間的聲音能量堆積太高，傳輸損耗在220赫茲到1千赫茲的頻率范圍內(nèi)是如此之低，噪聲排放不能最小化，所以一個沉默的空氣濾清器具有較高的TL 200赫茲到1 千赫茲的要求。</p><p>　　2.2無聲空氣濾清器的初步設計</p><p>　　如果有足夠的空間，一個復雜的結構，可以被分配到降低進氣噪聲排放。因此我們必須充分利用有

12、限的空間。在這項工作中用CAD軟件或Pro/E進行包絡發(fā)動機室中的其他汽車部件的剩余空間。然后從籠罩空間獲得的總體積所需的空氣濾清器。下一步是選擇合適的消聲器單元和它們的尺寸?？紤]空氣凈化效果，必須滿足兩個要求：（1）空氣流量應等于或超過原通量值；（2）過濾面積不能降解。在這要求的基礎上，對消聲器單元理論初步確定開采布局。空氣濾清器是由兩塊隔板分隔成三個膨脹室，右擋板的中間有個洞，左擋板有四個孔的四角，濾紙放在中間膨脹室的中心。因為這空

13、氣濾清器的復雜性，孔的直徑大于原來的。第二個要求是在第一擋板孔的直徑和長度的二室，讓過濾面積等于原來的，然后第二膨脹室的長度可以確定。所以空氣濾清器的幾何結構是由兩個變量確定的。</p><p>　　整體的聲學行為是三室的所有組成元件的行為總和。為了提供連續(xù)衰減譜寬的帶寬，在他們個人的貢獻衰減最小不應同時發(fā)生。為了調查三室個人的聲學性能，綜合空氣濾清器被分成三個部分，其中之一是擴張室消聲器單元，只是在兩擋板的位置

14、。邊界元法的運行進行計算的三個個體的聲學性能。第一室具有高和連續(xù)在300-1000赫茲頻段的衰減，并在400-800赫茲的頻率范圍的第二腔室具有高衰減的聲學性能稍微比第一個更糟。第三室性能最差，但在約230赫茲的頻率，其中第一和第二室的最小衰減，它具有更高的衰減，從而為第一和第二部分提供的補償效果。同時，在更高的頻率，第三部分可能是良好的聲學性能，這是在這個圖中沒有說明。請注意，這種單一的部分還介紹了之間存在不確定性，聲相互作用，即使他

15、們的個人表現(xiàn)，可以適當?shù)卮砘蚪?。明確的單一部分的聲學性能的初始設計提供了重要的信息。在某些領域的變化，集成系統(tǒng)在獲得最佳的聲學性能的詳細設計的邊界元法計算。</p><p>　　在最初的設計，外部幾何尺寸已確定，并且已用粗糙的尺寸單位選擇消聲器。在擋板的位置和四個孔的第二隔板半徑可以改變，以達到更好的聲學性能。</p><p><b>　　2.3噪聲排放預測</b>

16、;</p><p>　　直到現(xiàn)在，我們已經(jīng)完成了總體設計的無聲空氣濾清器。為了與原來的做一個比較，的噪聲輻射進行了預測。</p><p>　　為了驗證設計的空氣濾清器的實用性能，在5200轉/分鐘在發(fā)動機試驗臺作為原始和重新設計的空氣濾清器邊界條件或噪聲源在全油門和發(fā)動機轉速的測量是在發(fā)動機進氣道的聲壓，進而預測噪聲排放進空氣濾清器。</p><p>　　測量聲壓時

17、，空氣濾清器和發(fā)動機的噪音屏蔽掉。此外，由于在發(fā)動機的進氣端口測量壓力引起的噪聲信號的空氣流的影響和誘導麥克風干擾，惡化的發(fā)動機性能的困難，麥克風的測量定位在200毫米到進氣端口。邊界條件施加在空氣濾清器系統(tǒng)出口處應在測量位置上面提到的基于聲學理論從噪聲信號中提取的。</p><p>　　在進氣道軸的點P的聲壓與最高的相比，在相同的距離其他點的入口段中心。</p><p>　　2.4盡量減

18、少額外聲功率的方法</p><p>　　在使用以前的布局的一個潛在的問題是在173赫茲的聲音從空氣濾清器的進氣發(fā)射功率水平，頻率不為其他頻段的低。空置面積在管道連接空氣濾清器與發(fā)動機的進氣口表明其他一些可能的空氣清潔系統(tǒng)的改進。本文采用旁路管來實現(xiàn)這一目標。</p><p>　　提高TL在大約173赫茲的頻率為目標確定尺寸LD = 980毫米。比較預測的聲學性能上的布局與管和柔性分流管的布

19、局現(xiàn)狀沒有改變。旁路管道布置的聲學性能顯著提高在大約173赫茲的頻率和519赫茲的頻率的三倍，大致對應半波長，預計旁路管道布置TL輕度上升。</p><p>　　可以看出，無輔助空氣凈化器在173赫茲是最高的聲功率級，而旁路管空氣凈化器在這個頻率大大降低?？偮暪β仕綇?到1千赫，為無旁路管空氣清潔器110.2分貝，并為旁路管空氣清潔器105分貝。</p><p>　　請注意，引擎聲功率級

20、不從實驗檢測進氣系統(tǒng)噪聲112.2分貝和無聲的旁通管的空氣清潔器105分貝，所以重新設計的無聲空氣濾清器切實降低發(fā)動機整體噪聲為最小的進氣系統(tǒng)噪聲。</p><p><b>　　3結論</b></p><p>　　本文報道了一個邊界元法的輔助設計無聲空氣濾清器。在最初的設計中，基于聲學理論和要求并考慮空間約束，進行空氣濾清器總體積、空氣濾清器的粗糙的內(nèi)部尺寸的測定。之

21、后，一個有效的方法應用到173赫茲的頻率的聲學性能的改善。</p><p>　　邊界元法的聲學工程設計使用幫助迅速增加。本文的研究結果為無聲空氣濾清器的工程應用指南。</p><p>　　流量的影響在本研究中并沒有考慮。雖然平均流將不會對聲學性能影響顯著，這可能對空氣凈化性能的影響和濾紙的影響被忽略，盡管它可能會影響在高頻率的空氣濾清器聲學性能。未來的研究應包括在高頻率上的空氣凈化和過濾紙

22、上的聲學性能影響的流動的影響。</p><p><b>　　參考文獻</b></p><p>　　[1] Bilawchuk, S., Fyfe, K.R., 2003. Comparison and implementation of the various numerical methods used for calculating transmission lo

23、ss in silencer systems[J]. Applied Acoustics, 64:903-916.</p><p>　　[2] Davies, P.O.A.L., 1996. Piston engine intake and exhaust system design[J]. Journal of Sound and Vibration,190:677-712.</p><p&

24、gt;　　[3] Wu, T.W., Cheng, C.Y.R., Tao, Z., 2003. Boundary element analysis of packed silencers with protective cloth and embedded thin surfaces[J]. Journal of Sound and Vibration,261:1-15.</p><p>　　Virtual d

25、esign and performance prediction of a silencing air cleaner used in an I.C. engine intake system</p><p>　　HAO Zhi-yong, JIA Wei-xin, FANG Fang </p><p>　　(College of Mechanical and Energy Enginee

26、ring, Zhejiang University, Hangzhou 310027, China)</p><p>　　(Tianjin Internal Combustion Engine Research Institute, Tianjin University, Tianjin 300072,China)</p><p>　　E-mail: haozy@zju.edu.cn; j

27、iawx@zju.edu.cn</p><p>　　Received Jan. 17, 2005; revision accepted May 12, 2005</p><p>　　Abstract: This paper reports results of the authors' studies on the virtual design method used in the

28、 development of low noise intake system of I.C. engine. The resulting high pass-by noise at level above the legislative target at full throttle when engine speed was around 5200 r/min necessitated a BEM-aided redesign ta

29、sk, following the typical process of design and development of an intake system. During the initial design, based on the acoustic theory and the requirements and considering the c</p><p>　　Key words: Virtual

30、 design; Acoustic performance; Silencing air cleaner; Boundary element method (BEM)</p><p>　　INTRODUCTION</p><p>　　The primary function of an The primary function of an intake system is firstly

31、to efficiently channel fresh air to the engine, and secondly to minimize intake noise emissions. There are a number of current approaches for developing a more realistic method to improve intake system design. The object

32、ives include more effective silencing performance to meet increasingly severe legislative targets for reduced noise on the one hand, with optimized engine performance and fuel economy accompanied by im</p><p&g

33、t;　　A typical procedure followed during the design and development of an intake system for a vehicle engine is shown. The design process includes a careful tuning of all components of the intake system that influence noi

34、se emission with optimized matching of these to the engine operational and breathing characteristics influencing pollutant emission, performance and economy. Starting with an existing or notational system layout, an inte

35、grated assessment of the various performances is performed. This</p><p>　　The BEM widely used in the design of intake and exhaust system can be used to compute the interior, exterior, or both fields simultan

36、eously and only requires that the perimeter of the air cleaner be divided into elements;and the ease in imposing the boundary condition is another attraction. In this paper BEM is used to predict the air cleaner's tr

37、ansmission loss and noise emission. </p><p>　　The redesign of the original intake system arises in connection with a high pass-by noise with level above the legislative target at full throttle with engine sp

38、eed around 5200 r/min. The spectral characteristics of the noise signal are normally dominated by an extensive sequence of discrete tones that are harmonically related to the engine firing frequency which is 173 Hz corr

39、esponding to 5200 r/min and the inline 4-cylinder 4-stroke engine. In many instances the bulk of the acoustic energy fr</p><p>　　Traditional intake system with a function of noise reduction normally has two

40、parts: air cleaner and silencer. Due to the constraint of space in the engine compartment, the redesigned air cleaner combines the effect of cleaning and silencing. In this work, a so-called silencing air cleaner was red

41、esigned, with geometrical structure determined by predicted TL and sound power emission by BEM. Also, in order to minimize the sound power of the intake system at low frequency, a bypass pipe was added </p><p&

42、gt;　　DESIGN OF THE SILENCING AIR CLEANER </p><p>　　Original air cleaner evaluation </p><p>　　This original air cleaner of mainly cleaning design paying little attention to minimizing noise emiss

43、ion is its BEM mesh. </p><p>　　During calculation of TL, the outlet section of the air cleaner is given a unit velocity amplitude to model a sound source, all other surfaces are modeled as "acoustically

44、 hard" by default . The sound power of the outlet section can be calculated from the formula. All the subsequent TL predictions have the same boundary condition. </p><p>　　The predicted air cleaner perf

45、ormance is shown The sound power level at the engine intake port is shown . The peaks of the noise source signal are harmonically related to the engine firing frequency of 173 Hz. As the bulk of the acoustic energy from

46、 the engine combustion distributed among the low frequencies from 100 Hz to 800 Hz is too high, the transmission loss at the frequency range of 220 Hz to 1 kHz is so low that the noise emission cannot be minimized, so a

47、silencing air cleaner with a h</p><p>　　Initial design of the silencing air cleaner </p><p>　　If there is sufficient space, a complex structure can be assigned to minimize the intake noise emiss

48、ion. So we must make good use of the limited space. In this work CAD software Pro/E was used to envelop the rest of the space of the other automotive components in the engine compartment. Then the total air cleaner volum

49、e required is obtained from the enveloped space. The next step is to choose appropriate silencer units and their dimensions. Considering the effect of air cleaning, two requirement</p><p>　　The overall acous

50、tic behavior is a summation of the behavior of all constituent components of the three chambers. In order to provide a wide bandwidth of continuous attenuation spectrum, the attenuation minimum in their individual contri

51、butions should not occur simultaneously. In order to investigate the individual acoustic performance of the three chambers, the integrated air cleaner was separated into three parts, one of which is a silencer unit of ex

52、pansion chamber, just at the place of the t</p><p>　　In the initial design, the external geometrical dimension is decided, and silencer unit with a rough dimension is chosen. While the position of the baffle

53、s and the radius of the four holes in the second baffle can be varied to achieve better acoustic performance. </p><p>　　Noise emission prediction </p><p>　　Until now, we have accomplished total

54、design of the silencing air cleaner. In order to make a comparison with the original, prediction of the noise emission was carried out. </p><p>　　To verify the practical performance of the redesigned air cle

55、aner, the sound pressure at the engine intake port was measured at full throttle with engine speeds at 5200 r/min at engine test bed as the boundary condition or noise source of the original and the redesigned air cleane

56、r, then predicting the noise emission from the inlet of the air cleaner. </p><p>　　When measuring this sound pressure, the air cleaner was removed, and the engine noise was shielded off. In addition, due to

57、the difficulties in measuring the pressure at the engine intake port be- cause of the air flow influence on noise signals and the induced microphone disturbance that deteriorate the engine performance, the measurement lo

58、cation of the microphone was at the place 200 mm to the intake port, and at 45 to the normal of the intake port section . The boundary condition applied at </p><p>　　The sound pressure of the point P0 at the

59、 axis of the intake port is the maximum compared to the other points with the same distance to the center of the intake port section O.</p><p>　　EXTRA METHOD TO MINIMIZE SOUND POWER</p><p>　　One

60、 potential problem in using the previous layout is that at the frequency of 173 Hz the level of sound power emitted from air cleaner's inlet is not as low as that of other frequency bands. The vacant space around the

61、 pipe connecting the air cleaner and the engine intake port suggests some other possible improvements of the air cleaner system. This paper uses a bypass pipe to achieve this goal.</p><p>　　Increasing of TL

62、at frequency of around 173 Hz being the goal determines that dimension Ld=980 mm. Compare the predicted acoustic performance between the previous layout with no change on pipe and the present layout with flexible bypass

63、pipe. The acoustic performance of the bypass pipe layout improved dramatically at frequency of around 173 Hz, and at frequency of 519 Hz, corresponding roughly to thrice of half wavelength, the TL of bypass pipe layout i

64、ncreased lightly, as expected.</p><p>　　The resulting sound power level is illustrated . It can be seen that sound power level of the without-accessory air cleaner at 173 Hz is the highest, while that of the

65、 with-bypass-pipe air cleaner at this frequency is greatly decreased. The overall sound power level from 0 to 1 kHz, for the without-bypass-pipe air cleaner is 110.2 dB, and for the with-bypass-pipe air cleaner is 105.0

66、dB.</p><p>　　Note that the engine sound power level without intake system noise from experimental testing is 112.2 dB, and the silencing air cleaner with bypass pipe is 105.0 dB, so the redesigned silencing

67、air cleaner feasibly reduced the overall engine noise by minimizing the intake system noise.</p><p>　　CONCLUSION</p><p>　　This paper reports the designing of a BEM-aided silencing air cleaner.Du

68、ring the initial design, based on the acoustic theory and the requirements and considering the constraint of space, the total air cleaner volume and the rough internal dimensions of the air cleaner were determined. After

69、 which an effective method was applied to improve the acoustic performance at frequency of 173 Hz.</p><p>　　The use of the boundary element method to help in acoustical engineering design is increasing rapid

70、ly.The study results in this paper provided guidelines for engineering application of silencing air cleaner.</p><p>　　Flow effect was not considered in this study.Although the mean flow may not have signific

71、ant effect on the acoustic performance, it may have some effects on the air cleaning performance. The effect of filter paper was ignored, although it may influence the acoustic performance of the air cleaner at high freq

72、uency. Future study should include the flow effect on the air cleaning and the influence of the filter paper on the acoustic performance at high frequency.</p><p><b>　　Reference</b></p>&l

73、t;p>　　Bilawchuk, S., Fyfe, K.R., 2003. Comparison and implementation of the various numerical methods used for calculating transmission loss in silencer systems[J]. Applied Acoustics, 64:903-916.</p><p>　

74、　Davies, P.O.A.L., 1996. Piston engine intake and exhaust system design[J]. Journal of Sound and Vibration,190:677-712.</p><p>　　Wu, T.W., Cheng, C.Y.R., Tao, Z., 2003. Boundary element analysis of packed si