通常來說，排氣系統總是很難搶到“頭條”，哪怕已經配備了一些“酷炫”的先進電子系統。然而，下一代混合動力推進系統的工程師卻明白，如果有一套排氣系統不但能夠收集廢熱，運行時不會發出刺耳噪聲，甚至還能在純電力低速行駛模式下發出聲音提示行人，從而保證行人的人身安全，那這套排氣系統絕對是一項值得考慮的技術資產投資。
事實上，這正是我最近在天納克 53 英尺的演示拖車中的想法。在面前的桌子上，我可以看到一套采用TIG 焊接工藝的排氣系統，設計干脆整潔性，同時配備了一套完整的電子控制熱交換器和天納克的有源聲控系統“Smart Sound”。不過，作為一名記者，我面前的這些鋼管讓我不得不想起金屬貿易戰，以及這將對天納克公司價值 93 億美元的產品戰略產生什么影響。
我轉向邀請我來天納克的公司首席技術官 Ben Patel 博士。“作為一家全球化排氣和后處理系統一級供應商，你們總得用傳統的鋼管吧？”我問，“你們總不能把這些高溫器件也換成塑料的吧？”
Patel 博士的神色興奮起來，他說，“事實上，我們最后有可能真能這么干！目前，我們正在研究如何將復合材料應用至消聲箱，其實，不只是消聲廂，還有所有系統的‘冷端’部分。”
通過我們的整體式熱交換器，系統可以提取熱量，并將排氣溫度降低至可以使用高溫熱塑性塑料消聲箱的水平。“這樣一來，我們可以考慮使用更多替代材料了，”Patel 博士表示，“當然，接下來的挑戰是，如何將鋼材料和復合材料連接起來？這都是我們目前的研究主題。”
除了針對混合動力汽車的創新外，天納克憑借自身在駕駛控制技術方面的專業知識，為自動和自主駕駛汽車打造一種全新的懸掛系統，甚至包括一些非常激進的設計，根本目的是緩解自動駕駛汽車乘客可能存在的暈車問題。
“一級供應商正在見證汽車行業價值鏈的轉變，向自動駕駛、電力推進和網絡互聯方向的轉變。
IHS Markit 汽車總經理、資深分析師 Michael Robinet 表示，一些著眼當下的公司可能會忽視這些跡象，并按部就班地延續之前的做法。
“而天納克等公司的眼光卻已經放在了十年之后，他們真正理解未來將出現全新的商業模型，而且必須據此調整自身的競爭優勢。”Robinet 觀察道，“這些轉變意味著，供應界不僅需要作為這一轉變的積極參與者，更要成為引導轉變發生的引導者。”
天納克曾經是一家估值超 150 億美元的龐大企業集團，為美國海軍建造航空母艦等設備。如今，這家公司正專注于它在移動出行生態系統中需要扮演的最新角色：那就是為市場推出針對汽車和商用車的駕乘控制和后處理/清潔空氣系統，其中包括售后市場中一些非常著名的品牌，比如 Monroe、Walker 和 Clevite Elastomers 等。
正如 Patel 博士所稱，天納克的核心技術能力，也就是產品設計、包裝和系統集d成可能并不“炫酷”，但也同時受到客戶的高度重視。
緊湊裝配，產品增值
在電氣化和自動化的大背景之下，車輛的裝配必須更加緊湊，這也將給工程師帶來更多挑戰。Patel博士一邊指著一款蛇形排氣系統原型，一邊解釋說，電池、逆變器和其他電氣元件正在逐步侵占天納克設備在車輛中擁有的空間。
傳統的汽車“冷端”排氣系統包括中床諧振器、消聲器和 2 根尾管，這將占用大量空間，而且重量也不輕。在此背景下，天納克工程師為混合動力車打造了新的模塊化排氣系統，可以提供與傳統系統相同的聲學和背壓性能，但體積更小、質量更輕。
“如今，裝配可不是像往常那般容易，更小的設計往往需要極大的創造力。這可以讓產品在市場中占據優勢，即使它們含有較少的鋼材。”Patel 博士表示，“未來，各種車輛系統勢必將更加復雜，而相應的工程挑戰是將這些更加復雜的系統安裝在更小的體積中。這本身就是一種增值。你正在通過自己的努力，為你的顧客解決問題。”
如今，OEM不在會為每個平臺提供一種不一樣的設計。Patal 博士的團隊也旨在打造一種適用于不同汽車平臺的標準化模塊設計，比如將熱交換器與旁通閥都集成到排氣管中。對于混合動力汽車而言，這種設計非常具有吸引力，因為這可以滿足擋風玻璃的除霜要求，并同時在發動機預熱和客艙升溫之前加速變速箱的機油預熱。
Patel博士說，“我們的方法是提供少數幾套標準消聲器系統，滿足不同汽車廠商的多種發動機/預推進系統的需求。”
“我們可以使用同一套設計和裝配方式，并最終利用軟件進行最后的聲學調整。”Patel 博士指出，“消聲箱本身可能無法單獨提供產品團隊所需的音質，但有了Smart Sound 系統（天納克在長期聲學/降噪研發中的最新成果），我們可以通過增強、減弱或制造新的聲音，來調整消音箱的輸出。”
天納克的 Smart Sound 采用了圓頂型緊湊設計，安裝在車輛尾氣管末端。該系統采用了耐高溫的揚聲器、控制器和軟件算法。
正如一位廠商的工程師所言，Smart Sound 就像是用于調節“尾氣聲學效果”旋鈕。
創新懸掛，大有不同
在如火如荼的自動駕駛汽車革命之中，天納克的研發團隊也看到了重新深刻思考車輛懸掛系統和底盤系統設計的好機會。通常而言，專家普遍認為SAE 4 級和 5 級自動駕駛汽車研發的最大挑戰是緩解車上人員的暈車癥狀，而創新駕乘控制和懸掛系統將是克服這一挑戰的關鍵。Patel 博士承認，“最近的研究發現，四分之一的駕駛員在不開車時會感到暈車，包括我本人。”
未來，當自動駕駛穿梭巴士和私人自動駕駛汽車將更多成為人們的移動客廳和辦公室時，車上人員暈車的問題將更加明顯，部分原因在于車上部分座椅的方向將與車輛行駛方向相反。
“緩解車上人員可能出現的暈車現象， 是行業必須解決的問題，”Patel 博士斷言，“我們已經與該領域內的許多專家進行了討論，而且美國海軍也已就此問題進行了一些重要的研究。在汽車行業歷史中，解決暈車問題的需求從未如此迫切。如今，人們已經開始嚴肅對待暈車問題，而且也已充分意識到，暈車可能成為自動駕駛汽車必須克服的根本問題。
在此背景之下，天納克開始不斷加碼對創新懸掛系統的研發投入。通常來說，人們在形容車輛穩定性強時會將車輛比作高鐵。天納克的目的是盡可能地讓車上人員免受外界干擾。
“然而，未來車輛將開始執行很多不同任務，我們不能把車輛的移動僅限制在前后方向。”Patel 表示，“例如，車輛可能可以開始左右移動，從而更好地滿足停車需求。人們也會對車輛有新的期待。”
在介紹未來汽車底盤穩定性及對前后左右上下方向的控制能力時，Patel 博士不喜歡用軌道車輛來進行類比。在Patel 博士眼中，下一代汽車懸掛系統的動態性能將與“液體”更加相似。
“當你把一杯咖啡灑在桌子上時，咖啡就會以桌面的形狀存在。”Patel 博士解釋道，“為了徹底消滅車上人員的暈車，我認為這就是未來汽車必須實現的終極目標– 液體般的動態性能。
Patel 博士表示，“即使我們已經到了自動駕駛汽車的世界中，車輛行駛的道路也不會永遠平平整整，而且也不會永遠只有一種路面。未來，我們希望創造一種可以讓乘客享受液體般‘流暢’的乘車體驗。”
目前，天納克推出了大量電子調節式減震產品，這些產品可做到前后向兼容，并且能夠根據道路信息輸入主動調整懸掛角度。未來針對自動駕駛汽車先進懸掛系統的早期研發也可以從中受益。
五步研究，探索創新方向
Patel 博士透露，天納克在制定未來技術路線圖和相關產品投資計劃時采用了一種與一家外部設計創新公司聯合進行的獨特五步式研究。“在我們合作伙伴的研究過程中，核心就是通過洞察探索創新方向，”Patel 博士表示，“你必須拋出正確的問題，并尋求外部見解，這里的‘外部’不僅僅包括車輛動力學工程師，而且還有未來的道路建設者、輪胎制造商，當然還少不了消費者。”
“我們不只是詢問他們希望未來車輛具備哪些功能特征，我們還希望了解他們還有哪些感情方面的要求。”Patel 博士補充道，“舉個例子，人們在描述對自動駕駛汽車駕乘體驗的期待時，我們經常聽到類似‘流暢’這樣的詞。”
終端用戶的多樣性也迫使研發工程師必須從不同角度思考車輛的功能和情感屬性。Patel博士觀察到，“在產品開發的世界里，這種做法并不常見，人們通常只會根據功能要求進行設計和開發。”
天納克的研究將在 2018 年秋天結束，所有研究成果均將用于天納克團隊口中“創新之路”的規劃。
“這些‘創新之路’可以為我們帶來新的概念思想，這正是我們現在所處的階段，”Patal 博士指出，“在 3D 打印技術的幫助下，我們得以證明未來的車輛懸掛系統可能將與當下設計產生巨大差異，從功能上講也將與當下僅可在垂直方向減震的懸掛系統大有不同。”
這是否意味著目前無處不在的 MacPherson 支柱型懸掛系統將被淘汰？Patel 博士相信，是的，未來會有這么一天。
“舉個例子，生活在降雪帶的駕駛員希望車輛可以上升至足夠的高度，從而躍過比如車道盡頭的雪堆。這時，他們需要的可不是區區3 到 4 英寸，而是 18英寸的提升。只有這樣，這些駕駛員才能夠在天降大雪后仍然把車從自家院子里開出來。”Patel 博士表示，“我們一遍又一遍地傾聽客戶的意見。然后，我們會問自己這個問題：為了實現這一目標，我們需要做什么？我理解為什么有些人喜歡 SUV，因為 SUV 足夠高，但高度并不是所有客戶唯一想要的。”
Patel 博士表示，天納克的研究數據已經確定了數量“驚人”創新途徑，并且已經使高級工程團隊重新思考有關懸掛系統的傳統范例。“這可以讓我們領先自動駕駛趨勢一步，開始創造與當下車輛屬性完全不符的設計。”Patel 博士指出，“我們正在從全新的角度尋找研發和市場機會，這與過去 25 年所看到的情況完全不同。”
未來的自動駕駛汽車特點通?？梢杂?ldquo;CASE”來概括，即網絡互聯（Connected）、自動駕駛（Autonomous）、共享服務（Shared）和電動推進（Electric）。這意味著，車輛也將對懸掛系統和線控制動與轉向產生新的需求。從定義上講，懸掛設計就必須改變。
“我們問自己，'我們該如何重塑產品'？你如何才能拋開所有與制動、轉向和懸掛相關的范例？”Patel博士表示說，“我們會開發一個包含所有功能的模塊，采用完全不同的設計，所以最終成果將與今天的產品看起來大不相同。”
天納克的創新之路研究大約收集了 60 個概念，Patel 博士的團隊從中選擇了 5 個進行研發，并對其中一部分進行了 3D 打印。“當我們開始構建新概念時，我們通常會速戰速決，這些概念設計不必完美，僅僅出于驗證目的，我們只需要知道這種概念可行即可。”
Patel 博士表示，他的團隊很高興能夠成為第一批以科學方式介紹未來自動駕駛汽車數據的人。
“我們將建造與當下市場中完全不同的產品，”Patel 博士斷言，“并同時解決自動駕駛系統面臨的挑戰。”
Exhaust systems, even prototypes fitted with advanced electronics, are not typically the stuff that grabs big headlines. Engineers working on next-gen hybrid propulsion, however, know that a trick set of pipes capable of harvesting waste heat, while sounding sweet—and even creating sound to aid pedestrian safety during low-speed electric operation—is a technology asset worth considering.
Such were my thoughts recently inside Tenneco’s 53-foot demo trailer. On the table in front of me, a neatly designed and TIG-welded exhaust system featured both an integral, electronically controlled heat exchanger and active-acoustic control device the company dubs Smart Sound. But the steel tubing made my journalist’s brain wander to the metals-tariff war and its impact on this $9.3-billion supplier’s product strategy.
I turned to my host, Tenneco chief technology officer Dr. Ben Patel. “How does a global exhaust- and after treatment Tier 1 get around using traditional steel tube?” I asked. “You can’t covert these heat-bearing systems to plastic, right.”
Dr. Patel’s face lit up. “Well, eventually we might be able to! We’re investigating composite materials for muffler boxes—in fact, everything on the ‘cold’ end of the system,” he said.
Using the integral heat exchanger, heat energy is extracted to reduce exhaust temperatures down to where high-temperature thermoplastics can be used to mold the muffler boxes. “That gets us into the range of being able to consider alternative materials,” Dr. Patel said. “Of course, the next challenge becomes, how to join steel and composite material? We’re looking at all of this from a research standpoint.”
Along with new innovations for hybrids, there are also new initiatives to leverage Tenneco’s expertise in ride-control technology for creating new, and in some ways radical, approaches to suspension systems for automated and autonomous vehicles. An aim is to eradicate motion sickness as an issue for AV passengers.
“Scores of Tier 1 suppliers are witnessing a shift in the automotive value chain—towards increased levels of autonomy, electric propulsion and connectivity.
The short-term strategy would be to ignore the signs and continue unabated down the same road,” notes veteran analyst Michael Robinet, the managing director-automotive at IHS Markit.
“Tenneco is among those looking past the next decade—understanding that the business model and their comparative advantage will need to change,” Robinet observes. “Their transformations underscore that the supply community not only needs to be an active participant in this shift, but a leader within it.”
Once a vast $15 billion conglomerate that built (among many other things) aircraft carriers for the U.S. Navy, Tenneco now is precisely focused on where it needs to be in the mobility ecosystem: ride control and aftertreatment/clean-air systems for the automotive and commercial-vehicle sectors. The portfolio includes robust aftermarket brands including Monroe, Walker and Clevite Elastomers.
Tenneco’s core technical competencies—product design, packaging, and systems integration—aren’t glitzy, as Dr. Patel admits. But they’re also highly-prized by customers.
Packaging the value-add
Electrification and autonomy are causing vehicle packages to become tighter and more challenging for engineers, Dr. Patel noted, pointing to the snake-like proto-type exhaust system. The real estate that Tenneco used to “own” under the vehicle is being consumed by batteries, inverters, and other electrical components.
Where a traditional automotive cold-end exhaust system has a mid-bed resonator, a muffler and two tail-pipes—taking up a lot of space and weight—Tenneco engineers have new modular designs for hybrids that provide the same acoustic and back-pressure performance but are measurably smaller and lighter.
“No one is taking packaging for granted anymore. Smaller designs require great creativity and can command a premium in the market, even though they contain less steel,” he said. “The engineering challenge is to make the more complex products of the future work in smaller packages. It’s a value-add; at the end of the day you’re solving problems for your customers.”
Modular designs aimed at standardizing products across multiple vehicle platforms are part of Dr. Patel’s team’s strategy. OEMs are trying to move away from unique designs for every platform. Integrating the heat exchanger with bypass valve into the exhaust tubing is one approach. It’s increasingly attractive for hybrid applications in order to meet windshield-defrost requirements, while accelerating pre-heating of transmission oil ahead of engine warm-up and speeding-up cabin heating.
“Our approach is to offer a finite number of standard muffler packages—to serve OEM platforms that might have multiple engine/pro-pulsion variants with a single system,” Dr. Patel said.
“We can do the final acoustic adjustments in software using the same design and package; the muffler box on its own cannot deliver the sound quality the product team may want,” he noted. “Using our Smart Sound [the latest step in Tenneco’s long development of acoustics/noise cancellation technology] we can adjust the output by either amplifying/creating sound or cancelling it.”
Smart Sound is a compact dome-shaped unit fitted near the end of the tailpipe. It contains a high-temperature-resistant loudspeaker, a controller and software algorithms.
As one OEM engineer puts it, Smart Sound is “the fine-tuning knob for exhaust acoustics.”
Re-thinking suspension tech
The self-driving vehicle revolution presents Tenneco R&D with the opportunity to profoundly re-think vehicle suspension system and chassis system design. Ride control, and suspension in general, will be key to meeting what experts agree is a significant challenge for developers of SAE Level 4 and 5 vehicles: mitigating motion sickness for their occupants. Recent studies have found about 25% of the population suffers from motion sickness when they’re not the driver—”And I’m one of them,” Dr. Patel admits.
Today’s situation will increase exponentially when autonomous shuttles and private AVs, used as mobile living rooms and offices, offer backwards-seating arrangements.
“Motion sickness is an issue that the industry must solve,” he asserts. “We’ve talked with a lot of experts in this area and some important studies have been made by the U.S. Navy on this topic. In automotive, there’s never been a driving force to solve this problem; now, people are looking at it seriously and realize it will become a ‘gating’ issue for AVs.”
The challenge is fueling Tenneco’s most advanced innovation around suspensions. High-speed rail is the common analogy people use to point to where automobiles could be in terms of stability. The goal is to isolate the occupants as much as possible.
“But it’s not just isolating down to one dimension, because vehicles are going to start doing very different things in the future,” he said. “They’ll be capable of moving side-ways to optimize parking, for example. People’s expectations for them will be different than today.”
Dr. Patel doesn’t like to use the rail-car analogy in describing future chassis stability and utmost control of dive, pitch, squat and yaw. He believes a more accurate descriptor for where he sees next-gen vehicle suspension dynamics headed is “liquid like.”
“When you spill a cup of coffee on a table, the liquid takes the form of the surface it’s spilled on,” he explains. “That’s how I believe a vehicle ultimately needs to perform in isolating its occupants from all nausea-causing dynamics. That will come from a liquid-like interface.
“Even in the autonomous future, we’ll never have perfect road surfaces and a single topography. At the end of the day, we want to create an AV driving experience where you are ‘flowing’ on any surface you’re driving over,” he said.
Early investigations into advanced suspensions for future AVs leverages Tenneco’s current electronic shock offerings that are scalable, and capable of actively actuating a suspension corner according to road inputs.
Five-phase study sets the course
Helping to plot Tenneco’s future technology roadmap and related product investments is a unique five-phase study process the company is conducting with an out-side design-innovation firm, Dr. Patel revealed. “Core to our partner’s process for this study is insight-led innovation,” he said. “It forces you to ask the right questions from going out and extracting insights—in this case, not just from traditional vehicle-dynamics engineers, but from people making the roads of the future, making the tires of the future and from consumers.
“We didn’t just ask about the functional features they’d like to have in future vehicles; we also asked what are the emotional attributes they’re looking for,” he added. “We’ve heard a lot of words like ‘smooth’ to describe their expectations for AV ride quality, for example.”
Multiple profiles for end users are forcing the R&D engineers to think differently about functional and emotional attributes. “In the world of product development, that’s not something people commonly do; typically they design and develop to functional requirements,” Dr. Patel observes.
The study is set to conclude in fall 2018. All the ideas and hypotheses that it generated are being formalized into what the Tenneco team calls Innovation Pathways.
“Those pathways lead to concept ideas, which is the phase we’re in,” he noted. “Some of those concept ideas we 3D-printed to demonstrate that the suspension corner of the future is going to look very different and have extremely different functionality than the traditional up-and-down movement and damping that even our active suspensions have today.”
Does this mean the ubiquitous MacPherson strut-type suspension will be obsoleted? At some point, yes, Dr. Patel believes.
“Snow-belt drivers, for example, will want vehicles that can height-extend to clear the plowed-snow berm in the road at the end of their driveways. And extend not just 3-4 inches; they want to extend 18 inches to be able to drive out of their neighborhoods after a big snowfall,” he said. “We’ve heard that over and over from the customers. So, then we ask the question: What would it take to achieve this? It gets to why people like SUVs—they like the height but they don’t want it all the time.”
Tenneco’s study data has generated an “amazing” number of Innovation Pathways, he reports. And, he adds, it has caused the advanced-engineering team to rethink traditional paradigms regarding suspension systems. “It’s allowing us to get out in front of this autonomous-driving trend and start to create the vehicle attributes that are completely different than exist today,” he noted. “We’re picking up an R&D and market opportunity from a completely different vantage point than we’ve seen in the last 25 years.”
The so-called ‘CASE’ future—connected, autonomous, shared, electric—has included engineering concepts that integrate the vehicle drive motors within the hubs. That means the corner, in general, will have propulsion and by-wire braking and steering. By definition, then, suspension design has to change.
“We’re asking ourselves, ‘How do we reinvent the corner’? How do you throw out all the paradigms related to braking, steering and suspension?” Dr. Patel said. “We would approach it by developing a module for the corner that encompasses all of that functionality. Such a module would not look like any products today. Completely different design.”
Some 60 concepts were gleaned from the Tenneco study, from which Dr. Patel’s team selected five, including those that were then 3D-printed. “When we start building them, we’re taking the agile approach—they won’t be perfect. They’re just for proof-of-concept purposes to show it’s all possible.”
Dr. Patel said his team is excited to be among the first to introduce data on the AV future in a scientific way.
“We will build products that are completely different from the landscape,” he asserted, “while solving the problems to enable autonomous driving.”
Author: Lindsay Brooke
Source: SAE Automotive Engineering Magazine
2011 年加入天納克之前，Patel 博士曾在通用電氣公司工作了 13 年，擔任化學家、資深科學家和技術企業領導者等職位。圖為Patel 博士與天納克的主動懸掛產品。
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