據(jù)稱,與現(xiàn)行的 V 型六缸發(fā)動機相比,全新 3.0 L 直列六缸發(fā)動機的輸出功率和扭矩分別高達 294kW(394 hp)和 550 N·m(406 lb·ft),達到 歐6B 排放標(biāo)準(zhǔn),且重量還降低了 12 千克(26.4 磅)。
近日,捷豹路虎(Jaguar Land Rover)直列六缸發(fā)動機重新登陸公司最新攬勝(Range Rover)系列車型的決定可能會讓市場感到些許驚訝,但事實上這種發(fā)動機自八年前問世以來,一直位列捷豹路虎的產(chǎn)品開發(fā)名單。據(jù)了解,新款路虎攬勝的主要賣點在于性能提升,而捷豹路虎顯然認為I-6 直列六缸發(fā)動機相交其他 V 型排列六缸發(fā)動機具有明顯優(yōu)勢。
這款全新 3.0 升 I-6 發(fā)動機沿用了捷豹路虎Ingenium 系列I-4 發(fā)動機(單缸容量 500cc)的模塊化設(shè)計,輸出功率和扭矩分別高達 294 kW(394 hp)和550 N·m(406 lb·ft),搭配全新路虎攬勝運動 HST(頂配版本)完全可滿足 EU6b 排放要求,不輸任何其他以性能著稱的SUV。值得特別提起的是,該發(fā)動機搭配了一款電動增壓器,可借助車輛的48V 輕度混合動力再生系統(tǒng)提供動力,僅需 0.5 秒即可達到65000 rpm 的轉(zhuǎn)速。這種設(shè)計“幾乎消除”了雙渦管渦輪增壓器中常見的滯后問題,可在加速瞬間為車輛提供300 Nm/s 的扭矩加速度。
數(shù)年之前,路虎已決定逐步棄用購自福特(Ford)或 PSA 的發(fā)動機,并在 2020 年起為所有車型提供電動版選項。無論從哪方面講,這款I(lǐng)-6 發(fā)動機的問世都將協(xié)助路虎實現(xiàn)這些目標(biāo)。據(jù)了解,這款I(lǐng)-6 發(fā)動機將首先登陸新款路虎攬勝運動HST SUV 中,生產(chǎn)則將在公司 Wolverhampton工廠中專門開辟一條新產(chǎn)線進行。《汽車工程》歐洲區(qū)編輯Stuart Birch 針對這款直列六缸發(fā)動機的研發(fā)細節(jié),采訪了捷豹路虎發(fā)動機項目總工程師Jon Harris。
Ingenium 是一個支持不同燃料選項(汽油和柴油)的模塊化發(fā)動機系列,而這款I(lǐng)-6 發(fā)動機是否也是基于 Ingenium概念設(shè)計的呢?這又是從什么時候開始的?
Harris:這款六缸汽油發(fā)動機的確是基于Ingenium 發(fā)動機系列概念設(shè)計的,我們早在八年前就已經(jīng)開始了。Ingenium系列的重心最初是在四缸汽油發(fā)動機和2.0 升柴油發(fā)動機上,但 3.0 升 I-6 發(fā)動機也一直在我們的計劃中,而且從一開始也規(guī)劃了專門的生產(chǎn)設(shè)施用地。
捷豹路虎現(xiàn)在用的是48V 輕混動力系統(tǒng)。對此,您可以具體介紹一下嗎?
Harris:這款發(fā)動機配備了皮帶驅(qū)動的集成式起動機/發(fā)電機(BSG)以取代傳統(tǒng)配置中常見的交流發(fā)電機。具體來說,BSG可以為車輛提供電力,并將車輛超速運行期間損失的能量存儲在一個48V 電池中,并在后續(xù)行駛中通過皮帶傳動系統(tǒng)將這部分能量轉(zhuǎn)化為額外的扭矩,幫助內(nèi)燃機提高運轉(zhuǎn)效率、優(yōu)化運行狀態(tài),從而提高車輛的燃油經(jīng)濟性。BSG系統(tǒng)還有助于發(fā)動機實現(xiàn)“無縫”啟停,用戶在整個過程中幾乎無法察覺啟停切換。
捷豹路虎決定為這款I(lǐng)-6 發(fā)動機搭配電動增壓器和雙渦管渦輪增壓器,這主要是為什么呢?
Harris:法雷奧是我們的一級供應(yīng)商合作伙伴,為我們提供電動增壓系統(tǒng),從而配合主發(fā)動機渦輪增壓器的工作,將壓縮空氣輸送到發(fā)動機。捷豹路虎一向以出色的車輛駕駛性能著稱,而車輛駕駛性能在很大程度上是直接取決于發(fā)動機增壓系統(tǒng)的。法雷奧電動增壓器的主要作用是利用48V 系統(tǒng)中的能量,幫助壓縮機在0.5 秒內(nèi)加速至 65000 rpm,從而為車輛提供卓越的駕駛性能水平。
從四缸到六缸,公司為了實現(xiàn)這個轉(zhuǎn)變進行了哪些工作?您能提供熱效率方面的參數(shù)嗎?
Harris:為了容納額外兩個氣缸,但同時保證大多數(shù)次級部件的高度通用性,I-6模塊化發(fā)動機架構(gòu)采用了一套新的氣缸蓋、氣缸體和曲軸。
此外,我們還對發(fā)動機的核心燃燒系統(tǒng)進行了充分優(yōu)化,燃氣旋轉(zhuǎn)運動提高了40%,還升級了液壓閥。此外,發(fā)動機頂部還直接集成了為增壓空氣系統(tǒng)準(zhǔn)備的兩級中冷系統(tǒng)。這樣可以減少氣量,并精確控制增壓空氣的溫度,進而優(yōu)化經(jīng)濟效率、減排效果和性能表現(xiàn)。新型Ingenium 汽油六缸發(fā)動機的汽車制動油耗率為229 g/kWh。
這款 I-6發(fā)動機是完全由捷豹路虎內(nèi)部設(shè)計開發(fā)的嗎?是否有借助外部公司的幫助?
Harris:I-6發(fā)動機完全是捷豹路虎公司在考文垂Whitley 工程中心內(nèi)部設(shè)計完成的。
過去,V6 優(yōu)于 I-6 發(fā)動機的主要原因之一是其在滿足碰撞安全標(biāo)準(zhǔn)方面的優(yōu)勢?,F(xiàn)在的情況還是這樣嗎?此外,由于I-6 發(fā)動機僅需要一個氣缸蓋和一組歧管,那么成本優(yōu)勢也是公司推I-6 發(fā)動機的原因之一嗎?
Harris:在確定發(fā)動機配置時,直列和V 型發(fā)動機布局是一項非常重要的戰(zhàn)略決策,并且需要考慮許多問題,比如如何進行改進?可以通用哪些車輛和發(fā)動機裝配工藝?與模塊化Ingenium 系列是否有協(xié)同作用?以及如何控制重量和成本等等。
如今,一些技術(shù)的發(fā)展是否也是捷豹路虎I-6 發(fā)動機成為可能的原因之一?比如這款發(fā)動機搭配的電動增壓器。
Harris:為了提供世界一流的性能,我們的I-6 汽油發(fā)動機采用了許多高水平的先進技術(shù),比如沿用了2.0 升 I-4 發(fā)動機搭配的液壓連續(xù)可變氣門升程系統(tǒng)。
噴油器的噴射壓強已經(jīng)升級為250 巴,點火線圈能量也提升至108 兆焦,而且車輛的 48V 電動增壓器和雙渦旋渦輪增壓器將同時為發(fā)動機輸送空氣。
I-6 和V6 發(fā)動機的重量對比如何?功率輸出和扭矩對比呢?
Harris:新款捷豹路虎發(fā)動機I-6 發(fā)動機與現(xiàn)行的 V6 發(fā)動機相比,重量減輕了 12 千克(26.4磅)。
與環(huán)保意義更加明顯的V8 發(fā)動機相比,電氣化 I-6 概念發(fā)動機是否在動力供應(yīng)、NVH 和整體駕駛平順性方面有巨大優(yōu)勢?
Harris:電氣化I-6 發(fā)動機一直是捷豹路虎長期戰(zhàn)略規(guī)劃中的重要組成部分,我們希望引導(dǎo)過去駕駛V8 發(fā)動機車型的客戶向電動I-6 發(fā)動機車型轉(zhuǎn)型。
所有廠商都會尋找對標(biāo)技術(shù),這款I(lǐng)-6 發(fā)動機的功率輸出、NVH、總體質(zhì)量等參數(shù)都主要對標(biāo)了哪些產(chǎn)品呢?
Harris:我們的技術(shù)團隊在核心技術(shù)、性能、燃料經(jīng)濟性、NVH和重量等方面都與主要競爭對手進行了對標(biāo)。未來,預(yù)計這款發(fā)動機也將給行業(yè)和其他競爭對手提供更多對標(biāo)選擇,共同促進行業(yè)發(fā)展。
柴油發(fā)動機的近況如何?捷豹路虎還會繼續(xù)開發(fā)柴油發(fā)動機嗎?大家對柴油發(fā)動機的排放問題是不是經(jīng)常反應(yīng)過度了(二氧化碳排放實際已經(jīng)非常低了)?未來,在一個以混合動力為主的世界中,柴油發(fā)動機還有一席之地嗎?
Harris:我們認為,柴油和汽油動力系統(tǒng)將與純電動汽車并駕齊驅(qū),繼續(xù)發(fā)揮重要作用,這些產(chǎn)品也都是公司戰(zhàn)略的重要組成部分。近些年來,我們聽到了大量對柴油技術(shù)的誤解,但事實上技術(shù)沒有好壞,只有合適與否。我們應(yīng)該根據(jù)客戶的用車情況,為客戶推薦最合適的動力系統(tǒng)。如今,我們對清潔柴油的投資已經(jīng)初顯成效,捷豹和路虎車型都是目前市面上最清潔的柴油車之一。
柴油發(fā)動機在 SUV車型中的優(yōu)勢更加明顯,這種動力系統(tǒng)可以讓客戶享受游刃有余的扭矩輸出及一系列附加功能,牽引能力更是尤為突出。
The all-new 3.0L I-6 delivers a claimed 294 kW (394 hp) and 550 N·m (406 lb·ft) while meeting the EU6b emission standard and still providing a 12-kg (26.4 lb) weight-saving vs. the outgoing V6.
The market may have been surprised by Jaguar Land Rover’s decision to offer the latest Range Rover with an I-6 gasoline engine, but it’s been on the company’s development list since the Ingenium engine series was conceived more than eight years ago. With refinement a salient Range Rover selling point, it was determined the I-6 had sufficient advantages over a V6 (including manufacture) to tip the balance in its favor.
Derived from the company’s modular (500cc per cylinder) Ingenium-series inline-4, the new 3.0-L I-6 produces 294 kW (394 hp) and 550 N·m (406 lb·ft) while meeting the EU6b emission standard when installed in the new Range Rover Sport HST (top), putting it well into the SUV muscle league. The new mill incorporates an electric supercharger powered by a 48V mild-hybrid regenerative system capable of spooling to 65,000 rpm in 0.5 seconds. It “virtually eliminates” lag from the engine’s twin-scroll turbocharger, delivering a torque rise rate during transient accelerations of up to 300 Nm/s.
With the decision to move away from outsourced (Ford and PSA) engines made several years ago, the new I-6 contributes to Land Rover’s commitment of delivering an electrified option on all new models from next year. It will appear first in the new Range Rover Sport HST, and is manufactured on a new line at JLR’s Wolverhampton facility. Automotive Engineering’s Europe Editor Stuart Birch spoke with JLR’s engine programs chief engineer Jon Harris for details on its development.
Ingenium is a multi-role (gasoline and diesel) modular engine range, but was a 6-cylinder gasoline envisioned from its concept, and if so when was that?
Harris: The 6-cylinder gasoline engine was envisaged from the conception of the Ingenium engine series more than eight years ago. Initial focus was put on the 4-cylinder gasoline and diesel 2.0L engines, but the [inline] 6-cylinder 3.0L engine was always planned and the factory footprint provisioned from the outset.
You are using a 48V mild hybrid system. Can you put some more detail on that?
Harris:The engine is fitted with a belt-driven integrated starter/generator (BSG) which replaces the alternator. The machine acts as the electrical energy supply system for the vehicle and stores lost energy in a 48V battery during a vehicle over-run condition. The energy can then be reapplied as torque assist through the belt drive system to allow the combustion engine to run in a more efficient, optimized state delivering improved fuel economy. The BSG system also facilitates seamless engine stop/start events that are almost imperceptible.
JLR decided to use an electric supercharger and twin-scroll turbocharger for the I-6; can you provide some detail about that strategy?
Harris: We have worked with Valeo as the Tier-1 supplier to deliver the electric supercharger system, which works alongside the main engine turbocharger to deliver pressurized air into the engine. Vehicle drivability is a key attribute for Jaguar Land Rover and the selection of the engine boosting system is directly linked to the delivery of this attribute. The electric supercharger was developed to capitalize on the available energy from the 48V system and deliver class-leading levels of drivability by accelerating its compressor to 65,000 rpm in 0.5 sec.
What fundamental changes were made to the Ingenium engine to successfully add two cylinders? And can you provide some thermal efficiency numbers for it?
Harris: The I-6 modular engine architecture includes a new cylinder head, cylinder block and crankshaft to add the additional two cylinders, whilst maintaining high levels of commonality with many of the sub-level components.
The core engine combustion system has been evolved increasing gas tumble motion by 40% and introducing improved valve profiles through the hydraulic valvetrain. A two-stage intercooling system for the charge-air system has been incorporated directly within the architecture and mounts to the top of the engine. This delivers reduced air volume and accurate control of the boosted air temperature, assisting in delivering economy, emissions and performance. The new Ingenium gasoline 6-cylinder achieves a BSFC of 229 g/kWh.
Was the I-6 purely in-house designed and developed, or did you work with an outside consultancy?
Harris: The I-6 was purely engineered in house at the Jaguar Land Rover engineering center in Whitley, Coventry.
In the past, meeting crash safety criteria was one reason for V6 use over an I-6; has that picture now changed? Also, was cost a driver—i.e. only needing one cylinder head, one manifold set, etc. for the I-6?
Harris: When deciding on the engine configuration, the in-line versus vee-engine layout was an important strategic decision and many factors were considered. For example, refinement, vehicle and engine assembly-process commonality, design synergy with the modular Ingenium family, weight and cost were all part of the overall business decision.
Are the more technically advanced systems now available the enablers for JLR’s I-6 design? Your use of an e-supercharger would be an example.
Harris: High levels of technology have been integrated into the I-6 gasoline engine design to deliver a combination of world class attributes. The hydraulically continuously variable valve lift (CVVL) system launched on the 2.0L I-4 engine has been adapted for use on the I-6.
Fuel-injection pressures have been uprated to 250 bar and ignition coil energy is raised to 108 mJ. The air supply into the engine is from a combination of the 48V electric supercharger and a twin-scroll turbocharger.
What is the weight comparison between your I-6 and a V6 solution, each with comparable power output and torque?
Harris: The new Jaguar Land Rover engine I-6 engine has delivered a 12 kg (26.4 lb) weight saving versus the outgoing V6.
Could the electrified I-6 concept set a new global standard in premium power, NVH, and overall smoothness—rather than the less politically correct V8?
Harris: The electrified straight six engine is planned to be an important long-term product for Jaguar Land Rover. The expectation is that some customers will move to an electrified I-6 powertrain who previously have driven V8 powered products.
All OEMs benchmark technology— what competitors did you benchmark regarding specific output, NVH, overall mass, etc?
Harris: The technical teams at Jaguar Land Rover benchmark core technologies, performance, economy, NVH and weight vs. our key premium competitors. We expect that the new engine will also create benchmarking interest in its own right from the industry and Jaguar Land Rover’s competitors.
Where is the apparently fading diesel engine in all this? Is JLR continuing to develop diesel; has there generally been an over-reaction to diesel emissions (CO2 remains impressively low)? Does it have a future in a hybrid world?
Harris: We believe there remains a strong role for diesel and gasoline alongside BEV powertrains, and they all form part of our strategy. In recent years there has been plenty of misinformation around diesel technology. Depending on how the customer uses their vehicle should inform the correct choice of powertrain. Our investment into clean diesel is paying off; Jaguar and Land Rover models are among the cleanest diesel cars on the road today.
Particularly for our SUVs, customers enjoy the effortless torque and the added capability a diesel provides, especially when towing.
By Stuart Birch
SAE Automotive Engineering Magazine