對于工況卡車而言，如何在不犧牲關鍵牽引力和拖吊效率的前提下優(yōu)化車輛的空載行駛駕乘舒適度，是一項長期的挑戰(zhàn)。自2002 年以來，底盤技術供應商天納克(Tenneco) 已經陸續(xù)推出了多款連續(xù)可變半主動懸架系統(tǒng)(CVSA)。不久，這家供應商還將推出一款名為 DRiV 的更簡潔、更平價的半主動減振系統(tǒng)，主要定位皮卡和SUV 細分市場。
天納克的 CVSAe 系統(tǒng)采用了一款外接電子閥，可根據道路輸入和車輛對路面狀況的反饋，實時調節(jié)減振器的壓縮。系統(tǒng)的無限阻尼曲線（在最小/最大范圍內）由計算機算法產生，可操控電子閥，根據車輛傳感器傳回的車輪和車身數據做出反應。與CVSAe 系統(tǒng)相比，CVSA2系統(tǒng)的成本較高，采用了2 個電液閥，從而實現了壓縮和回彈的獨立控制，可以擴大校準范圍并提高駕駛員的舒適度和操控體驗。
對比之下，目前正在研發(fā)中的DRiV 數字懸掛系統(tǒng)則直接將傳感器和軟件控制集成在系統(tǒng)內部，采用了更加簡潔的集成式模塊化設計。DRiV系統(tǒng)預計將在 2020 年上市。天納克表示，DRiV 系統(tǒng)無需任何外部閥門或電子控制單元，因此非常容易集成至現有的懸掛系統(tǒng)中，幾乎無需對目前的機械或電子系統(tǒng)進行太多改裝。DRiV系統(tǒng)可通過驅動接口配置，分別提供8 種阻尼設置（駕駛員可通過信息娛樂系統(tǒng)的屏幕或驅動模式選擇器進行設置），而且還內置了一款簡化“網關”模塊，可為系統(tǒng)提供網絡安全保護，并支持車輛現有控制器局域網(CAN) 總線的通信。
專為極端環(huán)境設計
今年 6 月舉行的媒體發(fā)布會上，天納克副總裁、首席技術官Ben Patel 聲稱，DRiV是一款獨一無二的產品。他指出，DRiV系統(tǒng)的設計簡潔，能夠快速適應不同的路面條件，“非常適合希望通過易于集成的平價懸掛解決方案，優(yōu)化車輛駕乘性能的汽車制造商。”
在密歇根州 Pontiac 市附近的 WaterfordHills Raceway 試車場中，《汽車工程》跟隨一輛雪佛蘭Silverado，在試車場內專門設置的各種路面和彎道完成了一系列低速駕駛測試。測試證明，DRiV阻尼器能夠優(yōu)化車輛的駕乘和操控體驗，并顯著降低車輛的抖動、彈跳和制動下潛。毫無疑問，無論是空載或載重400 磅（181公斤）的情況下，裝配 DRiV 系統(tǒng)卡車的駕乘體驗和性能，都明顯優(yōu)于其他條件幾乎完全相同的載貨卡車。
我們采訪了天納克OE業(yè)務、汽車動力學和產品設計首席工程師Daniel Keil，并詢問了 DRiV 系統(tǒng)的應用是否需要在車身或底盤增加傳感器。“PCBA，也就是阻尼器內部的印刷電路板集成了傳感器、加速度計等一系列智能電子外設。” Keil 回答，“我們可以直接使用車輛現有的傳感器數據。此外，我們還可以從車輛獲得轉向、剎車、拖吊/載貨及越野模式 CAN 信息數據。”
這些阻尼器及其內部PCBA 能否抵御灰塵、雨水、風雪、污泥的干擾？這些都是貨運卡車經常遇到的嚴苛工作環(huán)境。“保護 PCBA、接口及相關元件免受腐蝕一直是產品上市面臨的主要挑戰(zhàn)之一。”Keil承認，“為了實現這個目標，我們已經做了大量工作。密封非常重要，我們將按照客戶的要求對鋼材料減震管增加防腐蝕涂層。”
客車定制
Keil補充說，DRiV技術也可用于乘用車輛，保證車上人員在常見及極端工作條件下的駕乘體驗，并同時保留干脆、利落的操控性能。
天納克首席工程師 Dan Keil 表示，天納克將根據不同廠商的要求，針對具體車型對DRiV 數字懸掛系統(tǒng)進行校準。“根據我們的算法機制，系統(tǒng)僅會在有需要時調用控件。因此，如果你是在高速公路上平穩(wěn)地行駛，阻尼器絕大部分時間均不會工作。然而，一旦有東西在你面前跳出來，而且你也立刻更換車道，系統(tǒng)則將進入控制模式，提供更多的阻尼。”
系統(tǒng)將在增加半主動控制前，校準被動閥門，接著“查看傳感器數據，并決定車輛具體在什么時候需要多少阻尼。”
在車輛整合方面，為了使用DRiV 系統(tǒng)，OEM需要將通信系統(tǒng)集成至車輛網關（即天納克和廠商系統(tǒng)之間的接口）。接著，“校準將由我們和廠商共同負責，”Keil 說，“如果 DRiV 系統(tǒng)的安裝尺寸與傳統(tǒng)減震設備相仿，那么系統(tǒng)的安裝完全不會影響懸掛的其他部分。”
DRiV系統(tǒng)并不會限制車輛的裝載或拖吊能力。“系統(tǒng)本身的目標就是協(xié)助卡車更好地完成日常工作，”Keil 補充說，而且還必須能夠符合OEM所設定的限制要求。此外，由于系統(tǒng)的控制力更強，車輛需要啟用懸掛系統(tǒng)的頻率將更低，這也可以在一定程度上優(yōu)化車輛的耐久性。
過去 10 到 15 年中，超過六百萬部天納克 CVSAe 系統(tǒng)已經成功登陸 10 家汽車廠商（主要為歐洲廠商）的超過40 款不同型號車型。目前，天納克公司正在向北美SUV 市場擴張。雖然簡化版DRiV 系統(tǒng)將主要針對全尺寸皮卡和SUV 細分市場，尤其是一些用于拖吊的車型。但2020 年后，該系統(tǒng)還將有機會登陸更多不同類型的道路車輛。然而，天納克公司目前并未計劃公布任何 DRiV 系統(tǒng)的客戶名單。
One enduring challenge of work-truck engineering is how to make the vehicles ride and drive comfortably when unloaded without diminishing their vital hauling and towing capabilities. Since 2002, chassis-technology supplier Tenneco has offered ontinuously variable semi-active suspension (CVSA) systems. It will soon launch a simpler, less expensive semi-active damping system called DRiV (Digital Ride Valve). It is aimed initially at pickups and truck-based SUVs.
Tenneco’s CVSAe systems use an external electronic valve to adjust damper compression in real time to road inputs and the vehicle’s body reactions to them. Their infinite damping curves (within minimum/maximum limits) are created by a computer algorithm that drives the valve’s reactions to wheel and body motions provided by sensors on the vehicle. The costlier CVSA2 system uses two electro-hydraulic valves to control both compression and rebound independently for a larger tuning range and higher levels of comfort and control.
But the simpler DRiV digital suspension technology now under development for a 2020 launch has an integrated modular design with sensors and software controls nestled inside the damper itself. With no external valve or electronic control unit, Tenneco says DRiV is easy to integrate into the vehicle’s existing suspension with little re-engineering of mechanical or electrical systems. It offers eight discreet damping settings with or without a driver interface (it can be driver activated through an infotainment screen or drive mode selector) and uses a simplified “gateway” module that provides cyber security and communication with the vehicle’s existing controller area network (CAN) bus.
Designed for extreme environments
DriV is "unique in the market,” claimed Ben Patel, Tenneco Vice President and Chief Technology Officer Ben Patel in a June release. He noted that the damper’s simplified design and ability to quickly adapt to road surfaces and conditions "make it an excellent option for manufacturers looking for an easy-to-integrate solution for improved ride performance in any vehicle segment…at an affordable cost.”
As Automotive Engineering experienced in a series of low-speed test drives of Chevrolet Silverados over and through strategically placed surface events and chicanes at Waterford Hills Raceway near Pontiac, MI, the DRiV dampers improved both ride and handling while significantly reducing shake, bounce and brake dive. There was no question that the DRiV-equipped truck, both unloaded and with 400 lb. (181 kg) of ballast behind its rear axle, was dramatically better in feel and performance than the near-identically equipped stock truck.
We asked Daniel Keil, Chief Engineer of Tenneco's OE Business, Vehicle Dynamics and Product Engineering, whether the DRiV system needs sensors added to the vehicle’s body or chassis. “The PCBA, the printed circuit board inside the damper, has sensors, accelerometers and all the electronics intelligence integrated into it,” he said, “and we use data from sensors already on the vehicle. We also get steering, braking, tow/haul and off-road mode CAN message data from the vehicle.”
Are these dampers and their internal PCBAs sufficiently protected from the dirt, water, snow, slush, etc. that hard-working trucks will experience over time? “Having to protect the PCBA and the other interfaces from corrosion and all the elements has been one challenge in getting this to market,” Keil admitted. “We have done a lot of work to protect those things. Sealing is very important, and we will follow customer requirements on the anti-corrosion coating of the steel damper tubes.”
Tunable for passenger cars
Keil added that the DRiV technology also can be used in passenger cars to provide smooth ride under normal conditions but transition to crisp, athletic handling on demand.
“It will be calibrated to each individual vehicle with the OEM based on how they want its DNA," he said. "The strategy we use in our algorithms is to call for control only when it’s needed. So if you're cruising on a smooth freeway, the dampers will be in soft mode most of the time. But if something jumps out in front of you and you do a lane-change, they will go into a controlled mode with more damping."
Engineers will tune the passive valving before adding the semi-active control, then "the system looks at the sensor data and decides how much you need and when you need it.”
Regarding vehicle integration, OEMs will have to integrate communications to the gateway [the interface between Tenneco's and the OEM's system] and harnesses to the DRiV system will have to be completed. Then, "the calibration will be a joint effort between us and them," Keil said. "If fits in the same space where a normal shock does, so the rest of the suspension does not have to be touched.”
He adds that DRiV technology does not limit a vehicle’s cargo or towing capabilities. “The intention is that it can do anything the truck can do,” he stated. “It has to be able to encompass the limits set for the vehicle by the OEM. And it will reduce the durability loads on the vehicle because it will have better control and hit the suspension stops less often.”
More than six million Tenneco CVSAe systems have been featured in 40 different models from 10 (mostly premium European) brands over the last 15 years. The company is now expanding availability to the North American SUV market. And while the simpler DRiV system will be initially aimed at full-frame pickups and SUVs, especially those used for towing, beginning in 2020, there may be opportunities for it down the road in a wide variety of vehicles. The company is not ready to name any customers for DRiV or to provide any cost information for it, however.
Author: Gary Witzenburg
Source: SAE Automotive Engineering Magazine
天納克 DRiV 數字懸掛系統(tǒng)模塊化設計的內部結構。該單元可通過驅動接口，分別提供 8 種阻尼設置，而且還內置了一款簡化“網關”模塊。（圖片來源：天納克）
