Imagine your equipment fueled entirely by what you grow: corn. It's already been invented. An all-ethanol engine developed by Ricardo Inc., claims to be as thermally efficient as a diesel, and to substantially improve upon ethanol's efficiency. It's called the ethanol-boosted direct injection (EBDI) engine.
“It turns the gasoline-ethanol equation upside down,” says Ricardo's Rod Beazley, director of its gasoline product group. “It has the performance of diesel at the cost of ethanol, and runs on ethanol, gasoline or any blend of both.”
EBDI solves many of the challenges of flex-fuel engines “because it's optimized for both alternative fuels and gasoline,” the company says. “Current flex-fuel engines pay an approximate 30% fuel economy penalty compared to gasoline when operated on ethanol blends such as E85.”
Director of the University of Nebraska's Tractor Lab Roger Hoy says, “You can convert a gas engine to burn ethanol, but if you start off designing an engine to primarily run on ethanol, that's very different. The advantage of its variable-valve timing coupled with electronic fuel injection is that the engine runs efficiently at any point in the operating map.”
Luke Cruff, Ricardo's EBDI chief project engineer adds, “EBDI represents an archetypal change for ethanol efficiency by taking advantage of ethanol's strengths — high octane and high heat of vaporization. While the lower heating density (Btu) of ethanol cannot be fully overcome, this technology allows us to reduce the gap between gasoline and ethanol consumption/mile by 33-50%, depending on the application.”
Ricardo's Beazley adds, “We can use a high level of turbocharging to achieve the high cylinder pressures made possible with ethanol. Add in some other advanced technologies such as direct injection, variable-valve timing, optimized ignition, advanced exhaust gas recirculation, and we're squeezing out more power than is possible with gasoline.”
It meets or exceeds Tier 4 emission standards, too. “In fact, it's very close to the best in class among U.S. engines,” Beazley says.
THE PROTOTYPE EBDI is a 3.2-liter V6 engine with a compression ratio ranging from 10 to 12 (compared to 9-10.5 for non-turbocharged gasoline engines and 8.5-9.5 for normal turbocharged engines).
It ultimately could replace a large gasoline or turbo-diesel engine in a large SUV, and is very scalable beyond the automotive and light-truck industries, Ricardo says. The first firing of the engine and initial development will be installed into a dual-wheel pick-up truck demonstration vehicle later this year. Expect to see the engine in the marketplace in 2013-2014.
Its torque matches that of a conventional engine twice its size, says Ricardo's Cruff. “The 3.2-liter engine is targeted at 500 hp, but the real story is not the peak power but the peak torque. On E85, the target torque is 900 Nm (665 ft-lb), or the same torque that the current production 6.6-liter Duramax diesel engine produces, but from less than half the displacement.”
The EBDI engine's fuel mileage depends on the vehicle it powers, and how that vehicle is being driven or used. “In a dual-rear-wheel pickup it's closed the gap to 21% so far, which is an approximate 36% improvement in relative terms when compared to current flex fuel engine technology,” Cruff says. “Ethanol works especially wellat high engine loads.”
This ethanol-powered engine is suited to “many different markets, including passenger cars, off-road and medium-duty (class 4 and 5) short-haul trucks and school buses that are centrally fueled,” Cruff adds. “Passenger cars are a big part of our market, and ag equipment of course.
“Because some areas of the country lack ethanol distribution, we make it operate on gas as well, but it's optimized for ethanol. Partly for that reason, class 8 over-the-road trucks are our final frontier, requiring more development, but it's not out of the realm of possibility,” Cruff says.
Veteran automotive journalist Mike Brezonick, Diesel Progress magazine associate publisher and editor in chief, lists the pros and cons of the EBDI engine from his perspective: “One, I am confident that technically the engine is probably all it's cracked up to be. Ricardo is a very well known design and engineering consultancy, and virtually all of the global engine manufacturers have employed it at one time or another to assist in their engine design or verification. They do really good work. So I have no doubt that from an engineering standpoint, the engine is world-class and performs just like they say it will.
“In my 20 years in this business, I have seen many ideas that at first glance seemed like really great ones,” Brezonick says. “These have included CNG engines, liquid natural gas engines, rotary engines of various types, free-piston engines, hydrogen engines, gasoline direct-injection engines, etc. All of their advocates could prove they worked and envisioned scenarios in which their developments would take the markets by storm. You will note, however, that for passenger vehicles, gasoline is still the dominant transportation fuel; and for commercial or heavy-duty applications, it's still diesel.
“They retain their positions because they work well,” he says. “New technology usually has to be demonstrably better than what's currently out there in order to supplant diesel or gasoline power. And it's really, really hard to be better.
“Ricardo's ethanol engine concept is a different kettle of fish and doubtless may find some applications over time. I would wonder ultimately how large the ethanol niche will be and how soon it might develop. And seeing that engine development is a very costly, time-consuming prospect, I also wonder exactly who would take this concept and run to market with it,” Brezonick says. (Ricardo designs engines and someone else has to actually build the products.)
There is “a lot of interest from many OEMs (including agricultural ones) on this type of engine,” Cruff says. “Interest is definitely growing. And EBDI is not limited to the ethanol niche because it's fully flex-fuel capable and optimized. It works well with ethanol, but also reflects the general advancement of gasoline (spark-ignited) engines taking place across the powertrain industry.
“Achieving energy independence is the advantage of the EBDI engine,” says Pella, IA, farmer and retired economics professor Ron Kaldenberg. “If you look back at American history, technology has always bailed us out. We really need to develop this technology and put it in the marketplace and solve our problem.”