在非公路用車的市場中，關(guān)于混合動力設(shè)備最有趣的一點應(yīng)該是其形形色色、五花八門的架構(gòu)和儲能方式。
“在其他行業(yè)，特別是乘用車行業(yè)內(nèi)，混合動力車的架構(gòu)都比較類似。”咨詢公司Ricardo Strategic Consulting副總裁Mark Kuhn在接受SAE雜志訪問時表示，“但非公路設(shè)備卻不一樣，單以儲能方式為例，你就可以選擇液壓能量回收、機械能量回收、電容和電池等各種不同的技術(shù)。”
Kuhn指出，約翰迪爾(Jone Deere)的一些裝載機，比如644 K和944 K型，甚至根本不會進行儲能，而是會將回收的動能立即使用掉。
“在設(shè)計這些設(shè)備時，我們發(fā)現(xiàn)儲能部件（比如電池）是最為昂貴的部分，而放棄儲能功能可以有效降低成本，且并不會影響車輛的實質(zhì)性能。”不斷采用創(chuàng)新手段以降低成本、提高效益，這就是非公路設(shè)備技術(shù)如此豐富多彩的原因。
約翰迪爾的工程基建和林業(yè)產(chǎn)品營銷經(jīng)理John Chesterman表示，“約翰迪爾進行了多方面的考慮，最終選擇了混合動力技術(shù)。”除了降低燃料消耗，其他考量因素還包括：弱化車速與發(fā)動機轉(zhuǎn)速之間的關(guān)聯(lián)、進行牽引力控制、進行拉力控制、提高設(shè)備耐久性，以及簡化操作等。
Chesterman表示，“944K型裝載機采用獨立的輪內(nèi)電機，可預(yù)防車輪打滑，而這是其他品牌的同級別裝載機在進行重載挖掘或推動時非常容易出現(xiàn)的問題。這種設(shè)計可以減少輪胎磨損，從而降低客戶的輪胎使用成本。”他同時指出，在設(shè)備上也會采用油冷系統(tǒng)、無刷交流電機和發(fā)電機，并對這些部件進行密封，以抵御灰塵和潮氣侵入。此外，使用輪內(nèi)電機的意味著設(shè)備不再需要倒車檔位。
“在需要倒車時，我們可以直接改變電機的方向，”他說，對擁有四個反向器的V型裝載機而言，這很容易做到。“我們的客戶發(fā)現(xiàn)，操作約翰迪爾混合動力裝載機要容易得多，一天下來工作輕松了不少。”Chesterman補充說，944K混合動力裝載機的用戶對設(shè)備的低油耗、總體表現(xiàn)和操作簡便等特性相當(dāng)滿意。
里卡多（Ricardo）公司的Kuhn表示，“我認為在施工機械設(shè)備中應(yīng)用混合動力技術(shù)，有助于該技術(shù)從公路用車向非公路設(shè)備的擴展。其結(jié)果非常顯著，你可以看看當(dāng)今工程機械設(shè)備的動力系統(tǒng)，多數(shù)都采用了混動技術(shù)。”這種設(shè)計已經(jīng)經(jīng)過質(zhì)量驗證，因而技術(shù)風(fēng)險更低。
采埃孚(ZF)就是一個很好的例子。公司非公路設(shè)備部副總裁Udo Kneitz表示，“我們可以在自己的研究范圍內(nèi)，探索各種各樣的趨勢，公司高級研發(fā)團隊會關(guān)注并分析多種儲能技術(shù)的發(fā)展。”
他認為，混合動力和電動系統(tǒng)都在不斷發(fā)展。“這種趨勢非常明顯，在常用PTO設(shè)備的農(nóng)機領(lǐng)域尤其如此。”
采埃孚的努力沒有白費，其ZF-TERRA+系統(tǒng)在農(nóng)機領(lǐng)域獲得了成功。有一種值得關(guān)注的混合動力技術(shù)，可以將發(fā)電機模塊整合至設(shè)備的變速箱外殼內(nèi)，支持輔助系統(tǒng)的供電。為了增強TERRA+系統(tǒng)的功能，采埃孚還有一款控制單元，用于進行能量與混合動力的智能管理。這款控制單元可以避免設(shè)備以地能效的方式工作，從而使車輛取得最高的能源效率。
采埃孚的電氣化和混合動力設(shè)計，均在公司提高效率的全面戰(zhàn)略舉措之列。Kneitz表示，采埃孚同時也需要一些其他基礎(chǔ)技術(shù)。
Kneitz認為，“在全機械液壓式功率分流CVT變速器的研發(fā)中，我們邁出了公司技術(shù)發(fā)展藍圖上的第一步。”他指的是公司適用于農(nóng)機設(shè)備的TERRAMATIC CVT變速器。目前，這款設(shè)備的最新版可以輸出450hp的動力。
Kneitz表示，“在我們看來，如果為了節(jié)能、降耗、提高效率而采用混合動力技術(shù)，最重要的一點就是升級動力傳動系統(tǒng)。”他同時指出，采埃孚TERRA+僅僅是電氣化進程中的一個例子。采埃孚還在為TERRAMATIC變速器加裝60-kW的發(fā)電機，這也同樣是公司產(chǎn)品電氣化進程中的項目之一。
Kneitz同時指出，除了農(nóng)機領(lǐng)域之外，這種混合動力技術(shù)在其他行業(yè)也頗具潛力。“我們也必須著眼于建筑機械領(lǐng)域，開發(fā)適合這些設(shè)備使用的混合動力系統(tǒng)，讓它們在未來的建筑工地上大顯其能。這項技術(shù)的發(fā)展一方面需要市場需求的驅(qū)動，另一方面需要政府排放法規(guī)的支持。”他說，“采埃孚的混合動力模塊搭配了一款高效電機，采用并聯(lián)混合動力模式，根據(jù)尺寸不同，輸出功率可達85到120kW不等。”在Kneitz看來，一旦市場做好電氣化準(zhǔn)備，采埃孚就能立刻行動。
作者：Bruce Morey
來源：SAE《非公路工程》雜志
翻譯：SAE 上海辦公室
Hybrid variety in off-highway
Perhaps the most interesting point about hybrids in the off-highway market is the sheer variety of architectures and energy storage choices.
“Other industries, especially passenger cars, feature similar architectures of hybrid electric vehicles,” stated Mark Kuhn, Vice President for Ricardo Strategic Consulting, in interview with SAE Magazines. “Not so in off-road, where you have hydraulics, mechanical energy recovery, and ultracapacitors as well as batteries.”
He pointed out that some wheeled loaders from John Deere, such as the 644 K or 944 K, do not store any energy at all, but re-deploys any regenerative braking energy instantaneously.
“When they designed this, energy storage (e.g., batteries) was the most expensive component and eliminating it reduced the cost while still providing substantial benefit,” he said. Coming up with novel ways to reduce cost and provide benefit is the driver behind variety.
“John Deere chose electric hybrid technology for several reasons,” said John Chesterman, Product Marketing Manager, for John Deere Construction & Forestry. Beyond reducing fuel consumption are a number of other reasons including: decoupling the engine speed from vehicle speed, traction control, rim pull control, durability, and ease of operation.
“The 944K with individual wheel motors can control the wheels from spinning out like they do on the other competitor’s loaders in this size class in heavy digging or pushing applications. This reduces tire slicing and tire costs for our customers,” said Chesterman. He also noted that they use oil cooled, brushless ac electric motors and generators that are sealed from dirt and moisture, and using motors means no reverse shifting.
“We simply reverse the direction of the electric motor,” he said, quite a convenience with a typical v-pattern truck load with four reversals. “[Our customers] have found that the John Deere hybrid wheel loaders are much easier to operate and reduce the amount of fatigue over the course of a day of operating.” He added that users of the 944K Hybrid are happy with the low fuel consumption, overall performance, and ease of operation.
“I think the ability to apply hybrid electrics for off-road construction equipment is an easier transfer of that technology from on- to off-road. As a result, if you look at all the hybrid architectures that are in equipment today, most of them are hybrid electrics,” said Ricardo's Kuhn. There is lower technical risk because it is more of a known quantity.
ZF is a good example of this. “We can exploit all kind of trends within our development landscape. [Many types of] energy storages are analyzed and monitored by the corporate advanced engineering of ZF,” explained Udo Kneitz, Executive Vice President ZF Off-Highway Systems.
He sees both hybridization and electrification as growing in off-highway. “This trend is to be seen especially in the agricultural segments where PTO-powered implements are very common,” he said.
This approach has its pay-off in the agricultural segment with its ZF-TERRA+ system. This is an interesting idea for electrical hybridization, incorporating a generator module integrated into a transmission housing to power auxiliary electrical loads. As an enhancement to the TERRA+, ZF offers a control unit for intelligent energy and hybrid management. The control unit is intended to avoid vehicle conditions with poor efficiency, thus achieving best operational performance.
For ZF electrification and hybridization are elements of a comprehensive plan for improving efficiency. According Kneitz, other baseline technologies were needed as well.
“With the development of fully mechanical-hydrostatical power split CVT transmissions we did a first step along our technology roadmap,” he said, referring to the TERRAMATIC CVT for agricultural equipment. The latest version is rated at 450 hp.
“To upgrade driveline technology in our eyes is the basis for any meaningful hybridization in terms of saving energy or fuel and increasing efficiency,” he said. He also noted that ZF TERRA+ is only one example for the electrification of implements. Adding a 60-kW generator system integrated into this TERRAMATIC transmission is yet another.
Kneitz also acknowledges the potential in other industries beyond agriculture. “We will see also hybrid systems for construction machinery driveline systems and drives on future construction sites. This technology evolution needs to be driven by market demand with reasonable total costs of ownership on the one hand and governmental emissions regulations on the other,” he said. “The ZF hybrid module works as a parallel hybrid with an efficient electric machine, providing up to 85 or 120 kW performance, depending on the size.” As far as he is concerned, as soon as the market signals its readiness, ZF will be too.
Author: Bruce Morey
Source: SAE Off-Highway Engineering
采埃孚的工程師利用一款電動輪頭(wheel head)，開發(fā)出一種適用于農(nóng)用機械的驅(qū)動解決方案。
采埃孚公司的Udo Kneitz認為，混合動力和電動元件及輔助設(shè)備，在當(dāng)今的非公路設(shè)備領(lǐng)域扮演的角色越來越重要。