隨著汽車混合動力解決方案的逐步普及，如何降低這些需要48V電系的復(fù)雜系統(tǒng)的成本，已經(jīng)成為了各汽車廠商與供應(yīng)商必須長期面對的挑戰(zhàn)，特別是對于相對售價較低的A級車、超小型車和微型車來說尤甚。在此背景之下，這對印度等因城市交通非常擁擠，小型車輛非常流行的新興市場來說，更是至關(guān)重要。
為了實(shí)現(xiàn)這個目標(biāo)，動力傳動系統(tǒng)和變速器設(shè)計專家公司——動力系統(tǒng)設(shè)計公司（DriveSystem Design (DSD) ）近日公布了一款輕度混合動力概念，據(jù)稱可以為更加精密（成本也更高）的全混動車輛系統(tǒng)回收高達(dá)60%的能量。此外，該系統(tǒng)還支持使用12V電系（無需升級至48V電系），因此非常有利于廠商的成本控制。
根據(jù)DSD公司技術(shù)總監(jiān)AlexTylee-Birdsall的介紹，這款新概念“特別適用于小型手動檔或AMT車型”。他補(bǔ)充說，目前，混動動力汽車在全球汽車總量中的比例仍非常低，我們實(shí)際上很難實(shí)現(xiàn)顯著的CO2減排效果。因此，增加小型混動車輛的數(shù)量將為全球CO2減排事業(yè)做出突出貢獻(xiàn)。
DSD系統(tǒng)可通過在車輛變速器的輸出側(cè)（車輪）安裝一個自由輪設(shè)備，而后通過自由輪連接12V電機(jī)。Tylee-Birdsall聲稱，這種系統(tǒng)能夠兼容手動變速器，可在發(fā)動機(jī)“熄火”狀態(tài)下，為車輛提供爬行和坡道控制等功能。該系統(tǒng)還能為車輛提供一種滑坡或航行模式，可在駕駛員松開油門時工作，進(jìn)而減少車輛換擋期間的扭矩效應(yīng)干預(yù)（AMT變速器的弊端之一）。
此外，該系統(tǒng)還可以在發(fā)動機(jī)關(guān)閉時繼續(xù)為車輛供電，進(jìn)而取得Tylee-Birdsall口中的“顯著CO2減排效果”。
這款自由輪設(shè)備可以便利發(fā)動機(jī)/變速器與車輪的分離，進(jìn)而減少阻力。根據(jù)DSD工程師的介紹，數(shù)學(xué)建模顯示，小型全混動汽車采用12V設(shè)備即可以實(shí)現(xiàn)超過60%的能量回收，且無需借助額外的高壓電池組、直流-直流轉(zhuǎn)換器及相關(guān)的控制系統(tǒng)。
隨著混合動力汽車市場份額的穩(wěn)步擴(kuò)大，廠商和一級供應(yīng)商的需求也正在逐步提高。為了支持公司自身與整個行業(yè)的測試需求，DSD公司最近又對自己的測試中心進(jìn)行了進(jìn)一步的擴(kuò)充，從而迎接決定性動力傳動系統(tǒng)效率需求帶來的特殊挑戰(zhàn)。
目前，DSD公司的研發(fā)工作主要集中在針對純電動汽車與混動汽車架構(gòu)的量產(chǎn)低噪聲齒輪設(shè)計、車軸與變速箱的性能優(yōu)化、輕質(zhì)設(shè)計及e-drive解決方案等。最近，DSD為公司的變速與傳動系統(tǒng)測試中心增加了3組新測試設(shè)備，將公司的測試單元總數(shù)增加至10個。DSD公司指出，為了實(shí)現(xiàn)測試中心的價值最大化，公司還一直在進(jìn)行內(nèi)部技術(shù)開發(fā)，解決決定性動力傳動系統(tǒng)效率的問題。
DSD公司首席工程師RobOliver解釋說，“隨著扭矩容量的增加，一些數(shù)據(jù)差異就顯得不這么明顯了。為了提高測量精度，我們已經(jīng)開發(fā)了大量自有技術(shù)，可以進(jìn)行扭矩傳感器校準(zhǔn)，進(jìn)而克服這個問題。”
此外，DSD的測試中心還可以在液壓系統(tǒng)裝配至變速器之前，提前集成相關(guān)電子元件。
目前，DSD測試中心中最大的測試單元含有5個電機(jī)，可取得7000 N·m (5163 lb·ft)的扭矩輸出和700 kW (939 hp)的功率輸出，非常適用于四輪驅(qū)動和混合動力車型，外加小型汽車、大型卡車及非公路車輛的動力傳動系統(tǒng)。
As hybrid solutions for cars gain broader applications, reducing cost in technology-dense systems that demand 48V power is a constant challenge. It is particularly important for A-segment cars, superminis and microcars and equally vital for emerging markets such as India, which have traffic clogged major cities.
To this goal, driveline and transmission engineering specialist Drive System Design (DSD) recently revealed a mild hybrid concept that it claims offers up to 60% of the energy recovery typically achieved by more sophisticated (and costly) full hybrids. And it can be done using 12V electrical architecture as a major contributor to cost control.
According to DSD Technical Director Alex Tylee-Birdsall, the new concept "is especially suitable for small vehicles with manual or automated-manual transmissions.” He adds that significant CO2 vehicle emissions reductions can’t be achieved while the hybrid population of vehicles globally remains low. So small, high-volume hybrids would make a significant contribution.
DSD’s system connects a 12V electric machine via a freewheel device on the output (road wheel) side of a car’s transmission. It is compatible with manual gearboxes and facilitates engine-off mode while the e-machine provides creep and hill-hold functionality, Tylee-Birdsall claims. The system also provides a coast or sailing mode when the accelerator is released, so reducing torque-effect interruption during gear shift (invariably an AMT downside).
And when the engine is switched off, the system continues to provide electrical power. It will deliver what Tylee-Birdsall describes as “significant CO2 savings.”
The freewheel device facilitates engine and transmission decoupling from the road wheel, thus reducing drag. According to DSD engineers, mathematical modeling has demonstrated that a 12V machine on a small car could achieve over 60% of the energy recovery of a complex full hybrid system, obviating the need for an additional high-voltage battery pack, DC-DC converter and associated control systems.
As hybrids steadily gain market share, OEM and Tier 1 suppliers’ requirements are growing. To support its own and the industry’s testing needs, DSD has expanded its test facility capabilities, developing it to meet the particular challenges of determining driveline efficiency.
R&D work is concentrating on robust low-noise gear design for high volume production, in addition to efficiency improvements for axle and transmissions and lightweighting and e-drive solutions for both pure EV and hybrid architectures. In the recently expanded transmission and driveline test center, three new test cells were commissioned, bringing the total to ten. The company states that to maximize the value of the expanded facility, it has developed in-house techniques designed to solve the problem of determining driveline efficiency.
Rob Oliver, the company’s Chief Engineer, explains: “As torque capacity increases, the differences we are looking for become a smaller proportion of the maximum figure. To improve measurement accuracy, we have developed our own techniques for the calibration of torque transducers which help overcome this.”
The test facility also has the capability to enable hydraulics systems to be combined with their electronics before assembly in the transmission.
DSD’s largest test cell incorporates five electrical machines having output motors capable of 7000 N·m (5163 lb·ft) and 700 kW 939 hp), catering to 4WD and HEVs, plus drivelines of small cars to trucks and off-highway vehicles.
Author: Stuart Birch
Source: SAE Automotive Engineering Magazine
DSD公司打造的12V e-machine，采用了自由輪變速器的概念設(shè)計。
DSD公司的12V輕度混合概念將非常適用于一些超級迷你的小型車，比如上圖中的日產(chǎn)Micra BOSE個人版。
最近，DSD為公司的變速與傳動系統(tǒng)測試中心增加了3組新測試設(shè)備。
