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.