由于擔(dān)心柴油排放物，特別是柴油排放物中的煙炱對民眾健康的不利影響，歐盟委員會出臺了歐V法規(guī)，將進一步對排放做出限制，并明確設(shè)定了限排值，也就是通常所說的PN值。按照新規(guī)定，對于輸出功率在19 - 560 kW（25 - 750 hp）之間的發(fā)動機，PN值不得超過1x10¹²/kW·h。
咨詢公司Integer Research的Fabricio Cardoso表示，除了以上規(guī)定外“歐V法規(guī)還擴大了適用于該規(guī)定的設(shè)備范圍。”輸出功率低于56 kW （75 hp）和高于560kW的發(fā)動機也必須接受管理。他表示，“歐五還將適用范圍擴大至鐵路、農(nóng)業(yè)、采礦和建筑設(shè)備，以及歐IV規(guī)定并未做出限制的雪地摩托、ATV（全地形交通工具）和移動發(fā)電機等。”
Integer Research公司會記錄選擇催性化還原（SCR）設(shè)備中的化學(xué)合成尿素在世界各地的銷售情況。這種物質(zhì)經(jīng)常被稱為AdBlue或柴油尾氣處理液（Diesel Exhaust Fliud），簡稱DEF。
“歐V法規(guī)的最大變化在于，設(shè)定了具體的限值。新規(guī)定的確是在不遺余力地推廣DPF（柴油顆粒過濾器）設(shè)備，”AVL Powertrain Engineering公司首席工程師Mike Kenhard表示，“事實上，這項規(guī)定說的就是使用DPF設(shè)備。”
Kenhard表示，對于很多發(fā)動機廠商而言這是一個好消息，因為他們已經(jīng)有了一些現(xiàn)成的DPF解決方案。他說，“對大多數(shù)廠商而言，歐V法規(guī)的執(zhí)行，意味著他們需要應(yīng)用這項技術(shù)，并從其他的既有產(chǎn)品中吸取經(jīng)驗，也有些廠商已經(jīng)開始采用DPF技術(shù)了。
Kenhard表示，對于發(fā)動機生產(chǎn)商而言，要應(yīng)對未來的歐V法規(guī)，面對挑戰(zhàn)最大的是小型發(fā)動機。他指出，大馬力發(fā)動機如果額外搭配后處理設(shè)備，可以提高價格以應(yīng)對成本的上升，但提價對小型發(fā)動機來說通常行不通。他說，“功率在56-kW及以下的發(fā)動機將面對很大挑戰(zhàn)。”
此外，現(xiàn)在生產(chǎn)商大多都希望產(chǎn)品能夠出售到全球各地的不同市場。但由于各個地區(qū)的排放法規(guī)存在差異，廠商不得不針對不同市場推出不同的產(chǎn)品。
英國發(fā)動機生產(chǎn)商珀金斯(Perkins)的產(chǎn)品營銷經(jīng)理Oliver Lythgoe解釋說，“當(dāng)一個國家想為非公路設(shè)備發(fā)動機制定排放標(biāo)準(zhǔn)時，最簡單的方法之一，就是借鑒一套現(xiàn)成的國際標(biāo)準(zhǔn)。”舉例而言，一些國家可能會直接參考?xì)WIII A（三階段）標(biāo)準(zhǔn)，而不是再去制定一套新標(biāo)準(zhǔn)。
其中，借鑒國際標(biāo)準(zhǔn)的關(guān)鍵在于，要結(jié)合自己所在地區(qū)的國情，符合配套基礎(chǔ)設(shè)施的現(xiàn)狀。“很多國家都想在減排上取得進展，但僅靠執(zhí)行標(biāo)準(zhǔn)是不夠的，市場中其他方面的發(fā)展也必須跟上，比如本地市場是否可以供應(yīng)超低硫柴油，以及柴油機尾氣處理液。”Lythgoe表示，“然而，隨著各地排放控制相關(guān)配套設(shè)施的不斷完善，我們預(yù)計在未來十年到二十年內(nèi)，世界各地的排放標(biāo)準(zhǔn)將趨于一致。”
即使是應(yīng)對當(dāng)今相對寬松的歐IV（四階段Final）法規(guī)，也并不容易，要控制功率較大的發(fā)動機排放污染，不采用后處理設(shè)備幾乎是不可能的。Lythgoe表示，“對于部分功率超過56kW的大型發(fā)動機，我們幾乎可以說，選擇性催化還原技術(shù)是唯一可以助其實現(xiàn)NOx減排目標(biāo)的可行方法，其他方法均會對設(shè)備的性能造成一定影響，這是不可接受的。”Lythgoe主張采用一種系統(tǒng)的方法應(yīng)對這一問題。
Lythgoe表示，“對于功率輸出在56 - 75 kW（75 - 100 hp）之間的發(fā)動機，廠商可以選擇與鉑金斯公司合作進行設(shè)備的整合。在很多情況下，通過這樣的整合，都可以將發(fā)動機的功率需求降至56 kW之下，從而降低成本,并減少安裝的復(fù)雜程度。”
作者：Bruce Morey
來源：SAE《非公路工程雜志》
翻譯：SAE上海辦公室
Stricter Stage V regs pose challenges
Worried about the adverse health effects of diesel exhaust in general, and diesel soot in particular, the European Commission’s new Stage V regulations will further reduce allowable limits on criteria emissions and place limit values on particulate number, often referred to as PN. For engines between 19 and 560 kW (25 to 750 hp), PN cannot exceed 1x10¹² per kW·h.
“Stage V also extends the range of machines required to comply,” said Fabricio Cardoso of Integer Research. Both smaller engines below 56 kW (75 hp) and larger engines above 560 kW would be regulated. “It also extends to new sets of railroad, agricultural, mining, and construction equipment as well as snowmobiles, ATVs, and mobile power generators that were not addressed in Stage IV,” he said.
Integer Research tracks, among other commodities, the worldwide sales of the chemical compound urea used in selective catalytic reduction (SCR) devices. This fluid is sometimes known as AdBlue as well as diesel exhaust fluid, or DEF.
“The big change with Stage V is the particulate number limits. It is really trying to encourage the use of DPFs [diesel particulate filters],” said Mike Kenhard, Chief Engineer for AVL Powertrain Engineering. “DPFs are the message behind the legislation.”
The good news for many engine providers, according to Kenhard, is that they already have those DPF solutions available. “For most people, implementing it means applying the technology and learning from other existing products or they already have it implemented,” he said.
The real challenges for engine makers in meeting a future Stage V is in the smaller engine categories, according to Kenhard. He noted that these typically do not command the price to justify additional aftertreatment equipment in the same way as larger horsepower engines. “56-kW engines and below is where it becomes very challenging,” he said.
Added to these challenges is the fact that OEMs today are interested in selling to multiple global markets. Increasingly fragmented emissions requirements are challenging them in offering a certified product for each market.
“When a country is considering introducing non-road engine emission standards, one of the simplest steps towards harmonization is for that country to adopt an existing globally recognized emission level,” explained Oliver Lythgoe, PerkinsProduct Marketing Manager. For example, a country may adopt a Stage IIIA/Tier 3 equivalent, rather than inventing their own.
The key to adopting such a standard is matching it to the supporting infrastructure that the country can provide. “While many countries want to make emissions improvements, progress can only be achieved at the same pace as other factors in the market such as the availability of good quality ultra-low sulphur diesel. Same with diesel exhaust fluid,” explained Lythgoe. “However, as appropriate emissions-related infrastructure continues to develop around the world, we could see global emissions standards move toward convergence over the next 10 to 20 years.”
Even meeting Stage IV/Tier 4F today requires careful consideration, and no foreseeable way of controlling pollutants without aftertreatment in the larger engines. “Above 56 kW, some form of selective catalytic reduction is really the only practical means of achieving NOx targets. Alternatives have been explored, but the effects on machine performance would not be acceptable,” said Lythgoe. He advocates a systems approach.
“One thing that OEMs can do for engines in the 56 to 75 kW (75 to 100 hp) range is to work with Perkins on machine integration. In many cases it will be possible to reduce the engine power requirement to below 56 kW, thus reducing machine cost and installation complexity,” said Lythgoe.
Author: Bruce Morey
Source: SAE Off-Highway Engineering Magazine
珀金斯公司旗下多款產(chǎn)品均已做好準(zhǔn)備，可應(yīng)對歐V法規(guī)。要應(yīng)對新規(guī)定，面臨挑戰(zhàn)較大的主要是小型發(fā)動機，以及在歐IV/四階段法規(guī)中并未涉及的設(shè)備。
AVL公司可為發(fā)動機的研發(fā)提供基于型號的系統(tǒng)設(shè)計工具。憑借AVL在該領(lǐng)域的多年經(jīng)驗，這套工具可幫助發(fā)動機生產(chǎn)商達到歐V法規(guī)的要求。