對汽車工程師來說，除了面臨如火如荼的汽車電氣化轉(zhuǎn)型所帶來的新挑戰(zhàn)之外，噪聲、振動與聲振粗糙度（NVH）等“老冤家”也并未走遠。在過去十年中，汽車行業(yè)憑借新的工具和知識成功解決了內(nèi)燃機汽車的 NVH 挑戰(zhàn)，大幅降低了最后關(guān)口“緊急修補”的必要性。然而，這些成果從另一方面同時提高了人們對電動汽車和混合動力汽車噪聲水平的期望，而值得注意的是，電動推進系統(tǒng)的噪聲問題本來就比內(nèi)燃機車型更難解決。
電動汽車客戶在吐槽車輛噪聲時總是毫不吝嗇。2020 年初，在一個特斯拉車主的在線論壇上，一篇針對“車內(nèi)噪聲評論”的帖子顯示，車主對特斯拉在“車內(nèi)噪聲”這一重要汽車衡量指標(biāo)方面的表現(xiàn)明顯不滿。以下摘選幾個例子：
一位特斯拉 Model 3 的車主寫道，“今天，我上 I-15S 公路開了一輛駕駛雷克薩斯 ES 350，這輛車要比特斯拉 Model 3 更安靜。”這位車主用分貝儀分別測量了兩輛汽車的噪聲情況。對比來說，在這條洲際公路上，特斯拉時速70 英里（112.6 公里）的噪聲水平為 74 dBA，但雷克薩斯在同等條件下的噪聲水平僅為 67 dBA，明顯更安靜。
一位奧迪的前車主表示：“這輛車 [特斯拉 Model3] 絕對比我以前的 A7 更吵，甚至我都不敢開到時速 110 公里（68 英里）以上。要知道，我平時可是經(jīng)常開到時速 160 公里（100 英里）的人。更糟糕的是，只要開到時速 110 公里以上，你就別指望用 Spotify 或 Tunein 聽任何古典音樂了，你根本聽不見，把音樂音量調(diào)高只會讓情況更糟糕。”
一位來自德克薩斯州的特斯拉車主承認：“沒錯，Model 3 確實比我之前的那輛車更吵，特別是在道路條件不好的情況下。雖然 Model 3 采用了‘靜音’輪胎，但它還是比我妻子的謳歌RDX 和我女兒的奔馳 C300 更吵。”
事實上，這些情況并不是 Model 3 或特斯拉獨有的，所有的電動汽車均面臨同樣的情況。
FEV 北美公司傳動系統(tǒng)開發(fā)、車輛工程和 NVH 副總裁 Kiran Govindswamy 表示，“盡管電動汽車的整體噪聲更低，但面臨的 NVH 挑戰(zhàn)卻更嚴峻。他說，“電動汽車沒有嗡嗡作響的內(nèi)燃發(fā)動機作掩護，因此車內(nèi)的任何噪聲都能聽到，很容易引起關(guān)注。其中，很大一部分是風(fēng)聲和道路噪音。目前，NVH 工程方面的工作重點是平衡車輛的動力總成、風(fēng)聲和道路噪聲的頻率。”
NVH 性能是評估車輛質(zhì)量的關(guān)鍵指標(biāo)之一，也是電動汽車的重要特征之一。電動推進系統(tǒng)在啟動階段和低速巡航階段的精致體驗是哪怕最順滑的內(nèi)燃發(fā)動機都無法媲美的。通常，當(dāng)電動汽車高速運轉(zhuǎn)的情況，車輛的寬帶噪音并不高，主要以純音為主。但隨著轉(zhuǎn)速不斷拉升，這種聲音就會變成惱人的高頻噪聲。此外，車輛逆變器在 10,000 Hz頻率附近工作時也會發(fā)出高頻噪聲。
對此，工程仿真解決方案制造商 Ansys 公司 Physics 業(yè)務(wù)部首席產(chǎn)品經(jīng)理 Marius Rosu 表示，“對于電動汽車研發(fā)工程師來說，車輛的電機噪聲是個大問題。在各種電機速度下，NVH 都無法避免，這不僅可能導(dǎo)致車輛疲勞受損，而且還會給車上人員帶來不適。”
電動汽車推進系統(tǒng)的噪聲包括來自牽引電機的電磁噪聲或來自動能回收（regen）模式下的發(fā)電機噪聲。“齒輪傳動系統(tǒng)也是一樣，總是吱吱作響，”Govindswamy 指出，“這是軸和軸承之間摩擦的機械噪聲，而且也是汽車廠商創(chuàng)造車輛標(biāo)志性聲音的位置。”
此外，電動汽車驅(qū)動單元還有一些其他的噪聲，即通常可以隱藏在內(nèi)燃機車型中的暖通空調(diào)（HVAC）噪音，包括電動熱泵循環(huán)的聲音，甚至還有車輛在停止時冷卻劑在電池組中晃動的聲音，這些聲音用戶都能聽到。對此，工程人員必須進行特殊設(shè)計，保證這些系統(tǒng)的工作噪聲都不能超過車輛本身的噪聲標(biāo)準(zhǔn)。
專家們表示，工程師可以通過結(jié)合使用有限元和多車身系統(tǒng)仿真工具，在組件、系統(tǒng)及整車層面進行優(yōu)化。這些工具可以幫助工程師分析輪系的動力學(xué)、軸偏轉(zhuǎn)、外殼結(jié)構(gòu)件以及驅(qū)動單元中的電磁力分布情況，從而避免了搭建原型所需的時間和成本，可以極大地便利工程師的降噪、降振工作。
NVH 是一種平衡的藝術(shù)：舉個例子，你的重點應(yīng)該是精益求精地調(diào)整齒輪的尺寸，從而減少噪聲源頭的噪聲？還是應(yīng)該專注于驅(qū)動單元結(jié)構(gòu)的敏感度，從而使其盡量不要放大進入車艙內(nèi)和外部世界的噪聲？此外，當(dāng)下，汽車行業(yè)為了提高燃油經(jīng)濟性而普遍采用輕質(zhì)化設(shè)計，這也會讓車輛更加容易受到 NVH 的影響。
“你必須在架構(gòu)設(shè)計和聲學(xué)包裝研發(fā)方面大膽創(chuàng)新，比如精準(zhǔn)調(diào)整動力總成和懸掛的安裝位置等。”FEV 公司的 Govindswamy 表示，“你必須找到一個最佳的安裝點，從而最大限度地減少車內(nèi)設(shè)計對噪聲的放大效果，”進而控制車輛的 NVH水平。
電動汽車廠商對控制車輛 NVH 的迫切需求催生了一個非?；钴S的專業(yè)供應(yīng)商領(lǐng)域：模擬工具提供商。這些提供商已經(jīng)有針對性的推出了數(shù)十個經(jīng)過驗證的仿真工具集，其中最受歡迎的是可以深入研究潛在噪聲根本原因的跨學(xué)科套裝。
位于密歇根州沃特福德市的 Kolano & Saha 聯(lián)合創(chuàng)始人兼首席顧問 Pranhab Saha 觀察到：“針對 NVH 的軟件工具往往是基于邊界元素、統(tǒng)計能量和氣體流動工作的，每個工具都有頻率范圍的限制。”正因為如此，他說，工程師們已經(jīng)在各種工具之間建立了“橋梁”，通過配合使用這些工具，從而在更廣泛的頻率范圍內(nèi)準(zhǔn)確預(yù)測頻率響應(yīng)情況。
“例如，NVH 聲學(xué)包裝材料通常工作在中高頻段，所以這些材料制造商通常會選擇統(tǒng)計能量分析工具，”Saha 解釋說，“但是，往往存在在較低頻率范圍中的輪胎腔噪音呢？此時，統(tǒng)計能量分析模型可能就無法發(fā)揮作用了，我們必須搭配其他軟件工具，從而拓展可以進行準(zhǔn)確預(yù)測的頻率范圍。”
舉個例子，電機中的磁力水平是機械和聲學(xué)分析的關(guān)鍵輸入量之一，也是準(zhǔn)確預(yù)測 NVH 的第一步。對此，比如 Ansys 就可以提供一種模擬電機噪聲的模擬工具，可以模擬電機氣隙內(nèi)磁力引起的電機噪聲。Rosu 表示，不同平臺之間的數(shù)據(jù)可以通用，比如來自 Ansys Maxwell 的瞬態(tài)電磁仿真平臺可以創(chuàng)建和測試數(shù)字原型，其輸出結(jié)果則可以直接作為 Ansys Mechanical 平臺的輸入資料，繼續(xù)完成諧波振動分析。
Rosu 解釋說，“在之前的版本中，我們的軟件僅可以生成單個工作點的聲譜，但如今已經(jīng)可以連續(xù)在多個速度點上生成聲譜，實現(xiàn)所謂的多轉(zhuǎn)速模擬。”
Maxwell 工具還提供了一些仿真模版，支持自動化模擬。在進行模擬時，工程師可能只需要指定一些電機的典型參數(shù)，比如相數(shù)、極數(shù)、插槽、材料、電機尺寸、線圈間距等，后續(xù) Maxwell 工具即可自動生成電機設(shè)計。（Maxwell 還允許直接導(dǎo)入外殼和電機型號參數(shù)。) Rosu 表示，“Maxwell 可以模擬電機在不同速度、電流、功率、扭矩等各種條件下的工作情況，幫助研發(fā)人員更好地了解電機的電磁性能以及機器運行過程中產(chǎn)生的磁力情況。”
在此之后，工程人員還可以將 Maxwell 的輸出結(jié)果直接輸入 Ansys VRXPERIENCE Sound 工具，繼續(xù)用于合成和評估電機噪聲及其對人類感知的影響。通過結(jié)合使用 Maxwell、Mechanical 和 VRXPERIENCE Sound 等多種跨學(xué)科工具，工程人員可以得到電機的聲學(xué)特性音頻文件，幫助工程師聽到電機在不同轉(zhuǎn)速下的聲音。Rosu 說：“有了電機的完整聲學(xué)資料，電氣和機械工程師就可以更有針對性的進行設(shè)計變更，從而降低控制 NVH 并同時滿足電氣性能。”
開發(fā)工程師認為，電動汽車開發(fā)最大的兩個挑戰(zhàn)是 NVH 和風(fēng)/輪胎噪音和振動。“內(nèi)燃發(fā)動機車輛也一直都有道路噪聲，但道路噪音和發(fā)動機內(nèi)部的一些噪聲的頻率一致，因此不那么明顯。”Saha 表示，“電動汽車中本來就沒有轟轟作響的內(nèi)燃機作掩護，因此任何輪胎/路面噪音都變得更加明顯。”
對此，輪胎公司正在開發(fā)更安靜的輪胎，在輪胎結(jié)構(gòu)中增加更多的彈性和阻尼，來減少輻射噪音。不過，如果靜音輪胎還是不能達到車輛的降噪目標(biāo)時，那車輛原始設(shè)備制造商就不得不在車內(nèi)添加更多加固襯料或聲學(xué)包裝材料，進而增加了車輛的重量和設(shè)計復(fù)雜度。“自從無內(nèi)胎輪胎問世以來，輪胎腔噪音的問題從未真正解決。”Saha 指出，“對于電動汽車來說，安靜的輪胎更為重要。為了解決 250 到 300 Hz 附近的腔體噪音問題，輪胎廠商已經(jīng)在輪胎內(nèi)部進行了大量工作，目的只有一個：盡量降低輪胎的腔體噪音。”
Saha 和其他專家斷言，最好的NVH 解決方案一定是從系統(tǒng)層面出發(fā)的。達索系統(tǒng)（Dassault Systemes）技術(shù)總監(jiān) Siva Senthooran 表示：“我們可以在組件級別對各個組件進行 NVH 優(yōu)化，但問題是當(dāng)這些經(jīng)過優(yōu)化的組件一下子全部放在一起時，往往無法達到客戶的NVH 要求。
達索系統(tǒng)的 SIMULIA 系列可以提供最全面的 NVH 模擬工具箱。SIMULIA 系列工具箱允許工程師在整個設(shè)計過程中，盡可能早地著手進行 NVH 分析，甚至不用等到原型準(zhǔn)備好以后。它解決了兩個關(guān)鍵問題：噪聲源和噪聲路徑。Senthooran說，SIMULIA 中的 PowerFLOW 套件可以“預(yù)測風(fēng)在車輛周圍的流動，以及其將以何種噪聲形式進入車艙”。此外，CST 工具也可以用于處理電磁噪聲源；達索系統(tǒng)的 Simpack 產(chǎn)品可以預(yù)測多體系統(tǒng)產(chǎn)生的力；Abaqus 適用于中低頻振動和聲學(xué)結(jié)構(gòu)耦合方面的模擬；Wave6 可以解決寬頻率范圍內(nèi)的噪聲傳輸和輻射路徑。
為了分析風(fēng)噪聲，NVH 工程師需要一個真實的外部形狀，但粘土模型不適合這種類型的研究，所以團隊必須等待聲學(xué)質(zhì)量原型就位。“PowerACOUSTICS 設(shè)計工具是 PowerFLOW 套件的一部分，主要用于車輛細節(jié)尚未最后敲定的早期設(shè)計階段，可以幫助工程師了解不同結(jié)構(gòu)可能會傳遞多少噪聲。”Senthooran 解釋說，“有了PowerACOUSTICS 工具，您就可以真實地預(yù)測車上人員未來將在車內(nèi)聽到什么。”這樣一來，原型設(shè)計一旦就位，工程師可以立馬著手進行優(yōu)化。“那時，工程師們已經(jīng)找到了設(shè)計中的大部分問題。”Senthooran 說，“當(dāng)快到表面設(shè)計凍結(jié)階段時，工程師將可以直觀地觀察到有關(guān) NVH 的問題，并與工作室合作提出解決方案。”
頂級 NVH 數(shù)據(jù)庫，支持電動汽車開發(fā)
當(dāng)被問及哪家供應(yīng)商的何種產(chǎn)品在他的 NVH 工作中發(fā)揮了“奠基性”作用時，一位來自底特律三大汽車巨頭的電動汽車研發(fā)工程師回答到，“FEV 公司的 NVH 數(shù)據(jù)庫。”
作為一家全車工程服務(wù)提供商，F(xiàn)EV 會定期為整個汽車行業(yè)的新車進行 NVH 性能基準(zhǔn)測試，并將測試結(jié)果加入一個目前已經(jīng)涵蓋超過 600 款車型和發(fā)動機的專有的數(shù)據(jù)庫中，允許客戶靈活地使用超過 100 多個指標(biāo)，用于制定零部件、系統(tǒng)和車輛開發(fā)計劃的目標(biāo)。
FEV 的工程師會基于數(shù)據(jù)庫中的數(shù)據(jù)，為各種指標(biāo)生成生成“散點圖”，展示整個汽車行業(yè)目前在該指標(biāo)方面的表現(xiàn)。Govindswamy 解釋說：“各種指標(biāo)都可以生成散點圖，比如發(fā)動機或驅(qū)動單元的輻射噪聲、安裝件的隔絕性能或車輛的聲學(xué)靈敏度功能。”
“NVH 數(shù)據(jù)庫讓我們能夠幫助客戶找準(zhǔn)他們的產(chǎn)品在 CAE 和開發(fā)測試中的位置，從而更好地支持客戶工作。”Govindswamy說，“你們是業(yè)內(nèi)最好的產(chǎn)品嗎？中間檔次？還是仍有改進的余地？通過找準(zhǔn)自己的位置，從而作出更好的開發(fā)決策，這是我們工作的核心。”
作者：Lindsay Brooke
本文原發(fā)表于
SAE《汽車工程》雜志
Noise, Vibration and Harshness, the engineer’s old nemeses, are among the new paradigms that electrification brings to vehicle development. The industry’s success in mitigating NVH in IC-engine cars and trucks — resulting in fewer 11th-hour “band-aid” countermeasures — was achieved in the last decade with new tools and knowledge. Those gains, however, are now the baseline for tackling what NVH experts say are greater challenges inherent in electric vehicles and hybrids.
EV customers are not hiding their displeasure. A review of the “cabin noise” comments in online Tesla owners’ forums from early 2020 reveal significant dissatisfaction in this important metric. Some examples:
“Today I drove a Lexus ES 350 on I-15S and noticed it is quieter than Tesla 3,” wrote one Model 3 owner, who recorded decibel readings in both cars. While the Tesla netted a 74 dBA at 70 mph (112.6 km/h) on that interstate road, the Lexus’s cabin was notably more serene, at 67 dBA.
Noted a former Audi owner: “It’s [Tesla Model 3] definitely noisier than my former A7 to a point where I dread driving above 110 km/h [68 mph] on the motorway whereas I routinely drove at 160 km/h [100 mph] with the A7. Worse, listening to classical music via Spotify or Tunein gets near to impossible above 110 km/h. Turning the volume up just makes things worse.”
Admitted a Texas-based Tesla owner: “Yes, the 3 cabin is louder than my previous cars, especially on less-than-perfect roads. Even with the ‘quiet’ tires, it’s undoubtedly louder than my wife’s Acura RDX and my daughter’s Mercedes C300.”
Those observations are not unique to the Model 3, or to Tesla. Owners of other EVs who are objective report similar impressions.
“The NVH challenges get tougher with EVs, even though the overall noise levels are lower,” said Kiran Govindswamy, VP of Drivetrain Development, Vehicle Engineering and NVH, with FEV North America. “It puts greater attention on other noise sources because there is no masking of noise as in an IC-engine vehicle. A big part of that is wind and road noise. The focus, in terms of NVH engineering, is balancing the frequencies between powertrain, wind and road noise.”
Favorable NVH behavior is a key indicator of vehicle quality—and a vital attribute in the context of electrified vehicles. Compared with even the silkiest IC-based drivelines, EV propulsion systems inherently exhibit superior refinement during start-up and low speed cruising. At the high rpm where electric-vehicle traction motors typically operate, there is little broadband noise. It’s mostly pure tone, but as rpm rises it becomes a high frequency noise. Power inverters also exhibit high-frequency noise in the range of 10,000 Hz.
“Tonal noise originating from the electric motor is a big concern for engineers designing these vehicles,” said Marius Rosu, lead product manager on the Physics business unit at Ansys, maker of engineering simulation solutions. “At varying motor speeds, NVH is unpleasant and may cause fatigue on the vehicle and discomfort for its occupants. “
EV propulsion system noise includes electromagnetic noise coming from the traction motor, or from the generator when in re-gen mode. “It’s also the geartrain orders, the gear whine,” noted Govindswamy. “It’s the mechanical noise from the shafts and bearings. And it’s the dynamics of how the shafts and housings interact to create the sound signature.”
And there are other audibles unique to EV drive units, typically masked in IC vehicles: HVAC noises. Electric heat pumps cycling. Even the sound of coolant circulating in the battery pack when the vehicle is stopped. All are obvious to the customer and must be engineered so that they operate below the noise ‘floor’ that’s already low in an EV.
That’s where experts say simulation, using a combination of finite-element and multi-body-systems tools, enables engineers to optimize component, system and full-vehicle design. The tools help analyze the dynamics of the gear train, shaft deflection, structural elements of the housing and the electromagnetic forces in the drive unit. The ability to predict both the design performance and the level of vibro-acoustic noise through simulation, without the time and cost of constructing prototypes, plays a significant role in mitigating noise and vibration (N&V) at a primary source.
There are tradeoffs: Should you focus on microgeometry changes to gears, for example, versus desensitizing the drive unit structure so that less noise is amplified into the cabin and the outside world? And the related vehicle structure, as it is made lighter to improve fuel economy, can cause the overall vehicle sensitivity to N&V to become worse.
“It forces you to get more creative with your architecture—including precise powertrain and suspension mounting—and more creative with the sound-package development,” FEV’s Govindswamy said. “You like to identify and design your attachment points to minimize the amount of amplification of the force input,” and hence minimize the level of NVH in vehicle.
Delving deeply into root causes
The urgency to reduce NVH in vehicles has spawned a lively domain of specialist suppliers, offering dozens of proven simulation toolsets for the complex task. The most popular of these are interdisciplinary, multi-physics packages that delve deeply into potential root causes.
“The software tools for NVH are boundary-element based, statistical energy-based, and airflow-based, and each of them have limits in the frequency range,” observed acoustics expert Pranhab Saha, co-founder and Principal Consultant with Kolano & Saha in Waterford, Michigan. Because of this, he said engineers build “bridges” among the various tools that allow them to predict frequency responses within a broader range.
“For example, NVH sound-package materials normally work at mid-to-high frequencies, so the tool their manufacturers use is statistical-energy analysis,” Saha explained. “But what about tire-cavity noise that is at a lower frequency? The statistical-energy-analysis model may not be able to predict this properly. So, there is a need for software tools that can be merged, to enable work in expanded frequency ranges.”
Calculating the magnetic forces in an e-motor, for example, is a critical input for mechanical and acoustic analyses. It is the first step towards predicting NVH. For that process Ansys, for example, offers simulation of e-motor noise caused by the magnetic forces acting inside the motor’s air gap. These excitation forces can be directly transferred from a transient electromagnetic simulation in one platform used to create and test digital prototypes (Ansys Maxwell) to a harmonic vibration analysis in another (Ansys Mechanical), according to Rosu.
“While it had been possible in previous releases to generate an acoustic spectrum for a single operating point, we are now able to walk through a range of rotational speed points in a so-called multi-rpm simulation,” he explained.
Full-motor design is automated using Maxwell’s template-based capabilities. The engineer need only specify the values for typical motor parameters — number of phases and poles, slots, materials, motor dimensions, coil pitch, etc. Once the parameters are specified, Maxwell automatically generates the motor design. (Housing and motor models also can be imported directly into Maxwell.) “Simulation of the motor in Maxwell over wide-ranging operating conditions involving varying speeds, current, power, torque, etc., provides useful insights into the motor’s electromagnetic performance as well as the magnetic forces that are generated during operation of the machine,” Rosu said.
Results are utilized in another tool, Ansys VRXPERIENCE Sound, to synthesize and evaluate motor noise and its impact on human perception. The multiphysics approach combining Maxwell, Mechanical and VRXPERIENCE Sound outputs an audio file of the motor’s acoustic configuration. Engineers can hear its sound at varying rpm. “With the complete acoustic profile of the motor,” Rosu said, “electrical and mechanical engineers can make changes to the design to reduce NVH while satisfying electrical performance requirements.”
OEM engineers developing EVs say their two biggest NVH challenges are wind/tire noise and vibration. “Road noise was always there in IC engine vehicles, but the spectrum of road noise and some of the IC engine noise are all in the same frequencies,” said Saha. “With the IC engine gone [in EVs] the tire-road noise becomes more critical.”
Tire companies are developing quieter tires, adding more elasticity and damping into the tire structure, to reduce radiated noise. When testing shows the tire falling short of noise targets, vehicle OEMs must add stiffeners or sound-package materials inside the vehicle and in the wheelhouse area, which add weight and complexity. “There is also tire cavity noise, which has existed since the advent of tubeless tires,” Saha noted. “It has become more critical with EVs. There is a lot of design and engineering focus inside the tire, to address the cavity noise issue which is around 250-300 Hz. We want to make that less audible.”
He and other experts assert that effective NVH mitigation is best handled at the systems level. “We could optimize at the component level, but once it’s all integrated into a vehicle the NVH behavior often does not meet the customer’s targets,” said Siva Senthooran, technical director for Dassault Systemes.
Dassault’s SIMULIA brand offers a comprehensive simulation toolset for NVH work. It was created to help engineers focus their NVH investigations as far up front in the design stage as possible—before prototypes exist. It addresses the two key bogies: sources and paths. Within SIMULIA, the PowerFLOW suite is used to “predict how the wind behaves as it flows around the vehicle, and the types of sources it will generate going into the cabin,” Senthooran said. For electromagnetic noise sources there is CST. Dassault’s Simpack predicts forces generated by multi-body systems. Abaqus is for vibration and acoustic structural coupling at low to mid frequencies. Wave6 addresses paths of noise transmission and radiation over a broad frequency range.
To analyze wind noise, NVH engineers need an exterior shape. But clay models are not suitable for this type of study, so the team has to wait for an acoustic quality prototype. “PowerACOUSTICS is a design tool that’s part of the PowerFLOW suite, used at an early stage when the design is fluid and you don’t have all of the vehicle details, to find out how much noise transmission you’re going to get from the structure,” Senthooran explained. “With PowerACOUSTICS you can actually predict what somebody is going to hear inside the cabin.” When a design is ready for prototyping is finally ready, engineers have had more time for optimization. “By then, they’ve discovered most of the issues in the design,” he said. “And when the design is close to the surface-freeze stage, engineers have the visual evidence showing the NVH-related issues and worked together with the studio to address the changes.”
Top NVH database supports development
When asked to name a supplier asset that he deems to be “fundamental” for his N&V work, a Detroit-3 body engineer involved with a new EV program replied, “That would be FEV’s NVH database.”
As a full-vehicle engineering services provider, FEV routinely benchmarks new vehicles from across the industry for their NVH behavior.
The benchmark data is fed into a proprietary database the currently covers more than 600 vehicles and engines, with more than 100 metrics used by customers for component, system and vehicle target-setting on development programs.
From the data, FEV engineers generate “scatterband” plots that present the state of the industry for a given metric. “A scatterband field might be radiated noise from an engine, or from a drive unit,” Govindswamy explained. “It might be isolation across mounts, or the vehicle acoustics sensitivity function.
“The NVH database has allowed us to support our customers by telling them where their products stand in both CAE and in the development state for testing,” he said. “Are you best in class? Mid-pack? Or is there room for improvement? Extensive development work supported by benchmarking is at the core of what we do.”
By Lindsay Brooke
SAE Automotive Engineering
在 FEV 公司的消聲室中，一部電動汽車驅(qū)動裝置正在進行 NVH 分析。通常來說，汽車驅(qū)動裝置的電磁和齒輪噪聲時常讓開發(fā)人員無比抓狂。
Kean Govindswamy 指出，F(xiàn)EV 的汽車行業(yè)基準(zhǔn)工作可以支持公司全面開展 NVH 開發(fā)工作。
達索系統(tǒng)（Dassault Systemes）的 SIMULIA 仿真工具套件旨在幫助工程師直觀地觀察各種與風(fēng)聲和道路噪聲有關(guān)的NVH 源和路徑，從而優(yōu)化車內(nèi)的噪聲環(huán)境。
Ansys 的 NVH 工具平臺包括 Maxwell、Motion、MAPDL 和 Dyna 等多個系列，旨在簡化開發(fā)人員的工作流程，可以以更簡潔的方式解決各個頻段內(nèi)的振動聲學(xué)問題，并減少所需的原型迭代數(shù)量。
輪胎制造商、電動汽車工程師和仿真工具提供商也在重新審視輪胎的腔內(nèi)噪聲問題以及輪胎與路面之間的摩擦噪聲問題。