约翰迪尔动力系统（JDPS / John Deere Power Systems) 公司控制系统与排放合规部技术经理 Gui Xinqun 博士表示，自己在未来动力系统展望方面“相当保守”。他说，“我认为，在很长一段时间内，内燃机仍将在汽车中占据一席之地。”尽管如此，Gui博士对“智能”后处理系统在车辆中的应用，及机械动力电动化方面的预测，却一点也不保守。

今年 9 月18 到 20 日举办的SAE 2017 商用车工程年会期间，Gui博士受邀参加了动力系统集成技术分会嘉宾讨论。他接受了SAE《卡车与非公路工程》杂志主编Ryan Gehm 的采访，介绍了一些 JDPS 公司的最新技术和项目开发情况。

SAE: 对JDPS来说，满足欧五排放规定要求是否还存在挑战？

Dr. Gui:  JDPS 已经准备好迎接欧盟 Stage V 规定的到来。事实上，目前，我们绝大多数符合 Tier 4 (Final)/欧四法规要求产品，已经可以达到欧五的排放标准要求。从我们的Interim Tier 4/Stage IIIB 发动机产品开始，公司一直在使用可以达到欧五排放法规要求的相关技术，累计使用时长超过4.25 亿小时。凭借所积累的丰富经验，我们在向欧五标准过渡的过程中处于非常领先的位置。

SAE: 您认为哪种先进燃烧策略能够最大限度地满足更严格的排放限制要求？

Dr. Gui: 我们的低湍流燃烧技术取得了一定成功。这种燃烧技术的排放水平很低，而且由于气缸内的热量损失最小，因此还具备不错的流体效率。目前，公司有部分拖拉机产品已经采用了低湍流技术，效果非常不错。未来，我们还将在更多产品中应用这一技术。谈到燃烧技术，我们需要继续着眼于气缸、气缸盖、空气系统及燃料喷射参数等关键发动机设计要素，密切关注细节的优化。发动机设计从来都不能仅关注某一个点，而是要从各个方面入手，实现系统的整体优化。

SAE: 低温燃烧技术是 JDPS 的研究重点吗？

Dr. Gui: 作为世界首家非公路设备制造商，JDPS 一直以提供各类可靠的商用冷却 EGR 系统而著称。EGR 系统正是低温燃烧技术的基础，各种形式的低温燃烧都必须借助冷却 EGR 技术来实现。在非公路设备市场，由于灰尘、砂石、极端工作温度和剧烈震动的存在，工况更加严苛，EGR系统面临的挑战也更大，会影响到设备的可靠性。因此EGR 系统必须足够强健，以适应各种严苛的工作环境。低温燃烧和低湍流燃烧技术都是JDFS 公司不断创新的动力。

SAE: JDFS 公司后处理技术有什么最新进展？

Dr. Gui：设备减重和封装优化仍是我们的首要任务。这很好理解，随便打开任何一辆拖拉机的引擎盖，里面一定塞得满满当当，没剩多少空间。在这种情况下，封装优化和设备减重就显得非常重要了。从技术方面来说，JDFS公司一直在努力借助创新的催化剂技术和排放控制校准，推动后处理系统的小型化。我们的下一代后处理解决方案可以成功缩小20% 的体积，并减重 40% ，这可以使封装设计更加灵活，设备安装也更加便利。我认为，封装优化和设备减重是未来的大趋势，这在未来几年内都不会改变。

SAE: 如何在未来几年内实现更高的封装效率？

Dr. Gui：精益求精，永远是产品设计中不可或缺的一部分，JDFS 也一直在坚持持续改进。我们的先进非对称基板具有进气通道和出气通道尺寸不同的特点，此类新型基板技术可以帮助提高封装效率，带来更好的减重效果。另一种值得关注的提效解决方案，是采用“更高效”的催化剂。具体来说，“高效”是指同样计量的催化剂，可以在更大的温度范围内发挥作用，提高物质的转化率。此外，由于使用了更高孔隙率的基板，制造商还可以在空间大小不变的情况下加入更多的催化剂。以上三个例子，仅仅是有望协助发动机制造商实现进一步改进的部分技术实例而已。

SAE: 电子控制技术领域现在发展怎样？

Dr. Gui：我们预计，未来将出现一款全新的发动机电子控制系统。该系统将采用多核处理器，控制和诊断功能都得到进一步提升。我认为，由于未来的先进发动机控制单元(ECU) 将能够对发动机及诊断系统的性能提供更强有力的控制，因此对传感器的依赖将有所降低。在传感器方面，我们的目标是将传感器的数量减少到最低限度。虽然并不知道最终我们的产品到底会需要多少个传感器，但无论如何，我们将不遗余力地减少每一代产品所需的传感器数量。我们的目标是延长设备的“正常运行时间”，能让设备每天都能为用户正常工作，这是我们最为关注的。

SAE: 仿真技术在改善减排效果方面作用如何？

Dr. Gui：仿真技术在改善减排效果方面的作用巨大。我们的基本目标是在确保发动机能够正常工作前，尽量推迟打造发动机原型的时间。在投入原型建造工作之前，我们希望能够准确预测发动机的性能、可靠性、耐用性和成本，而仿真技术能够有效帮助我们实现这一目标。目前，我们已经取得了很大的进展，未来还将继续投资开发仿真技术，从而优化我们的设计、开发、校准、校验和验证活动。

SAE: 在未来几年中，汽车领域还将出现哪些新技术呢？

Dr. Gui：我认为，在未来的几年里，电子控制系统领域的投资将继续增加。发动机的智能水平和功能性都将更强，这不仅仅是指排量或功率，还包括更可靠的运行表现，这也是大家的共同期望。另外，系统的远程信息处理、远程诊断和预后功能也将继续增强。我认为，这些功能将更加完备，覆盖到更多的设备，而且也将越来越智能化。此外，我们有望取得进展的另一个领域是设备电气化。JDPS公司通过 644k 和944k 混合动力装载机的研发，在电力驱动方面积累了丰富经验。我认为，未来大家将在电力驱动系统的整合与应用，及相关电气化产品的研发方面看到更多进展。

SAE: JDPS 是否还在开发其他的替代能源动力系统？

Dr. Gui：我们致力于为客户提供最佳的动力系统解决方案，满足客户的各种应用需求。为此，我们正在不断研究多个领域中的新技术和新进展，其中肯定也包括替代能源动力领域。然而，正如我之前说过的一样，我在未来动力系统展望方面“相当保守”。我认为在相当长的时间内，内燃机仍将活跃在汽车舞台上。”非公路设备市场要求很高，相关产品必须能够满足比道路车辆更加严苛的工况要求，因此非公路设备的发动机需要能量密度足够高的燃料，才能满足作业的动力需求。当然，非公路设备的动力需求水平也各不相同，这也使得在某些领域的替代能源解决方案具备发展的可能性。

Dr. Xinqun Gui, Manager of Technology, Control Systems and Emissions Compliance for John Deere Power Systems (JDPS), considers himself to be “fairly conservative” in terms of his powertrain outlook: “I think the internal combustion engine as we know it today still has a pretty long life ahead.” Even so, his expectations for improvements in engine “intelligence,” aftertreatment packaging, and machine electrification are anything but conservative.

Gui, who will be a panelist in the Powertrain System Integration technical session taking place at SAE COMVEC 17, from September 18-20 (http://www.sae.org/events/cve/), recently spoke with Editor-in-Chief Ryan Gehm about some of the latest technologies and development efforts at JDPS.

Any challenges left in meeting Stage V regulations?

John Deere is ready to meet Stage V regulations. In fact, most of our Final Tier 4/Stage IV products are already Stage V ready today. We’ve been using the technology needed to meet Stage V emissions since our Interim Tier 4/Stage IIIB engines and have over 425 million hours using the technology. Because of this experience, we are positioned very well for the transition to Stage V.

What advanced combustion strategies do you foresee making the greatest impact to meet stricter emissions limits?

We have been successful with low turbulence combustion. It offers low emission levels and is fluid efficient due to minimal heat loss in-cylinder. We applied low turbulence technology to some of our John Deere tractors with very good results and will continue to apply it in future products. In terms of combustion technology, we need to continue to consider engine design elements such as power cylinder, cylinder heads, air systems, and fuel injection parameters. We pay close attention to details. It’s not one single thing, but rather a variety of refinements for system optimization.

Is low-temperature combustion a major focus at JDPS?

John Deere has an established record of reliability since becoming the first off-highway engine manufacturer to widely commercialize cooled EGR, which enables low-temperature combustion. Every form of low-temperature combustion utilizes cooled EGR technology today. In the off-highway market, EGR has been a bit more challenging than on-highway due to the rigors of those applications, such as dust, debris, extreme operating temperatures, and vibration, which if not addressed can cause reliability concerns. The technology has to be robust enough in every environment. Low-temperature combustion along with the low turbulence combustion for higher efficiency is [the impetus] for innovation.

What’s the latest in aftertreatment technology?

Weight and packaging continue to be a primary focus. When you open the hood on a tractor, for example, there isn’t much space left for the addition of anything else. Optimizing the packaging and reducing weight are very important. From the technology side, John Deere has been working to leverage new catalyst technologies and emissions control calibrations to enable the downsizing of aftertreatment. Our next-generation aftertreatment solutions deliver greater package flexibility and offer easier installation while providing up to a 20% reduction in size and up to 40% reduction in weight. The focus upon optimizing packaging and weight reduction are trends I expect to continue for the next several years.

How can you achieve more packaging efficiency in the next several years?

Refinement is always part of engineering, and continuous improvement is what we do. New advanced substrate technologies like an asymmetric substrate, which features a different size for the inlet channel versus the outlet channel, is an example of a potential technology that may allow manufacturers to achieve more packaging and weight reduction efficiencies. Another potential avenue might be higher efficiency catalysts—the same amount of catalyst working at a higher conversion efficiency across a broader temperature range. And with higher porosity substrate, you can also put more catalyst into the same volume. So those are just three examples of technologies that engine manufacturers could potentially leverage for further improvements.

How about electronic controls—what’s going on in that area?

In the future, we anticipate there will be a totally new generation of engine electronic control systems that will be more capable, with multicore processors and advanced capability in controls and diagnostics. I think we’ll actually see less reliance upon sensors as advanced engine control units (ECUs) will offer greater control of engines and diagnostics performance. In terms of sensors, my goal would be to reduce the number of sensors to the minimum necessary. We’ll try to reduce the number of sensors necessary in every generation of our products; we don’t necessarily know exactly where that will end. One of our mantras is uptime—the product has to work for the customer each and every day. That’s a primary driving factor more than anything else.

What is simulation’s role in improving emissions reduction?

Simulation plays a huge role in improving emissions reduction. Our intent is to delay building a prototype engine until we have confidently predicted how the engine is going to perform. We want to be able to predict engine performance, reliability, durability, and cost—all of that—before we build any prototypes. That’s our vision. We’ve made a lot of headway with this, and we’ll continue to invest in simulation platforms that aid our design, development, calibration, verification, and validation activities.

What can we expect technology-wise in the years ahead?

In the coming years, I think we’ll see continued investment in electronic control systems. Engines will become smarter and more capable—not only in terms of lower emissions or higher power, but more reliable to run in the way people want. Telematics and the remote diagnostics and prognostics capabilities of those systems will continue to expand. I think those capabilities will become more and more readily available, as well as more intelligent. Another area of advancement we expect to see continue is electrification—John Deere has extensive experience with electric drives due to our 644K and 944K hybrid loaders. I think you will continue to see more advancements in the integration and use of electric drives and similar electrification of products.

Any other alternative power sources that JDPS is pursuing?

We are committed to offering our customers the best power solutions for their specific application needs. To that end, we are continually examining new technologies and advancements in many areas, which may include alternative power sources. However, my view is pretty conservative—as I mentioned before, I think the internal combustion engine as we know it today still has a pretty long life ahead. The off-highway market is very demanding and requires a product that can stand up to many more rugged demands than those used in on-highway applications. Due to these demands, off-highway engines need a fuel source that has enough energy density to meet the power needs of those applications. Of course, even off-highway applications can vary in their degree of demand, which can present opportunities for alternative power sources in some niches.

Author: Ryan Gehm
Source: SAE Automotive Engineering Magazine