Sneak Peek! Ford's "Bobcat" Dual Fuel Engine

Sneak Peek! Ford's

A radical twin-fuel engine from Ford, code-named “Bobcat,” that variably blends gasoline and ethanol on demand to realize diesel-like performance continues to make steady progress in its development, according to presentations made by the automaker to the Department of Energy and Society of Automotive Engineers in April. The presentations also provide a first look at the engine’s architecture and make some remarkable claims about “E85-optimized” engine efficiency versus size.

The Bobcat engine starts with a small turbocharged engine with separate gasoline and ethanol (E85) fuel injectors for each cylinder. The gasoline system mixes fuel and air in the motor's intake manifold using port injection. The second system uses direct injection to introduce small amounts of ethanol directly into the combustion chamber to control premature detonation, or knock, which results from the high temperature and pressure of a turbocharged engine. The ethanol prevents knock by cooling the air/fuel mixture until the engine is ready for combustion. With knock suppressed, the compression ratio can be increased.

Ford’s engineering partner, Ethanol Boosting Systems, LLC of Cambridge, Mass., has trademarked the term “DI Octane Boost” to describe the process; the direct injection of ethanol effectively increases the octane of regular gasoline from 88-91 octane to more than 150 octane.

The percentage mix of gasoline and ethanol varies according to load. In low- to medium-load conditions, only port-injected gasoline may be required. Direct-injected ethanol is added and increased as a function of load but only in the amount necessary to prevent knock. Using such technology, a 5.0-liter V-8 Bobcat engine could potentially produce 500 horsepower and 750 pounds-feet or more of torque.

Two 3-D computer-rendered diagrams included in Ford’s DOE presentation show the front and rear views of such an engine using a 90-degree V-block design. Two massive air/water heat exchangers sit atop the engine to cool turbocharged air before it enters the throttle body and intake manifold. Twin turbos sit on the lower right and left sides.

A separate engine cutaway diagram of a Bobcat motor shows the positioning of a gasoline port injector and ethanol direct injector. The gasoline and ethanol would be stored in two separate fuel tanks.

Sneak Peek! Ford's

EBS claims that relative to today’s common port fuel injected gasoline engines in cars and light-duty trucks, direct-injection ethanol boosting would provide a fuel efficiency gain for typical combined city/highway driving of 25 to 30 percent, at an incremental cost of $1,100 to $1,500, depending on the size of the vehicle. The efficiency gain and torque are comparable to current turbodiesel engines, like Ford’s 350-hp/650 lbs.-ft. 6.4-liter Power Stroke, but at about a third of the cost and with the advantage of cleaner emissions without expensive exhaust aftertreatment hardware.

Ethanol boosting also promises 5 to 10 percent greater fuel economy than Ford’s new line of gasoline-turbocharged direct-injection EcoBoost engines, which it’s based on. Ford’s DOE presentation says, “The E85 optimized engine and the dual fuel concept are logical extensions of Ford’s ‘EcoBoost’ strategy.”

Another way to measure efficiency, regardless of engine architecture, is through a metric called Brake Mean Effective Pressure. BMEP quantifies the amount of work an engine can do versus its displacement by measuring the average pressure exerted on an engine’s pistons. The more efficient an engine is, the higher its BMEP score.

According to Ford’s SAE presentation, an experimental 3.5-liter GTDI EcoBoost engine modified with E85 direct injection and gasoline port fuel injection run on a dynamometer achieved a BMEP score of 305 psi (27 bar), which translates to approximately 553 pounds-feet of torque and 316-hp at 3,000 rpm (flat torque curve from 1,500 to 3,000 rpm). The experimental engine was limited by the engine block’s ability to handle higher compression ratios. In comparison, a standard GTDI EcoBoost engine on a dyno was rated at 17 bar, which translates to approximately 350 pounds-feet of torque and 300-hp at 4,500 rpm (flat torque curve from 1,500 to 4,500 rpm).

As we mentioned earlier, ethanol use increases with engine load. A potential drawback to the Bobcat engine would be access to an ethanol refueling infrastructure, especially when a truck is working hard pulling a trailer or climbing hills.

Ford’s SAE presentation provides several range estimates for refueling a 5.0-liter Bobcat V-8 with a 10 gallon E85 tank and 26 gallon gas tank compared to a current Ford F-150 with a 5.4-liter V-8 and 26 gallon gas tank. Under mild driving conditions, the 5.0-liter E85 tank might have to be refilled only once every 20,000 miles and the gas tank refilled every 528 miles. Today’s 5.4-liter V-8 is said to have a 486 mile range under these conditions. However, an extreme towing scenario with the 5.0-liter V-8 pulling a fully-loaded trailer up a constant 6 percent grade could mean refilling the E85 tank as often as every 100 miles. That would be more often than the gas tank, which has an expected range of 243 miles under those conditions. Today’s 5.4-liter V-8 is said to have a 99 mile range under these conditions.

If the ethanol tank did run dry, the Bobcat engine could operate indefinitely with lower performance using only gasoline until a source of E85 could be found.

Under most operating conditions, however, Ford’s Bobcat engine could be the right powertrain at the right time to meet newly mandated corporate average fuel economy requirements that require fuel efficiency standard for all light trucks (crossovers, pickup trucks, SUVs and vans) to rise to 30 mpg by 2016, from 23.1 mpg today.

Will it work in the real world? Ford will try out its theories outside of computer simulations and the laboratory before the end of the year when a Bobcat engine is tested in an F-Series pickup for the first time.


Genius! The easiest way to boost the performance of any engine is to increase the compression ratio, and you've got to hand it to Ford engineers for figuring out that directing both gasoline and ethanol would result in a lot of efficiency. Very smart.

Personally, I don't think the separate E85 tank will hurt this setup at all. Ford dealers can be the designated re-fueling point for all Ford owners, and if Ford is smart (and they certainly seem to be), they'll subsidize E85 costs for their owners. More return visits to the dealership for E85 will boost dealership revenues.

More dealership visits usually result in more sales too (and better brand retention).

Great story Mike!

Specification for the BobCat

CGI in the block it´s the only way to cope with the mentioned pressures.

@Sint: Thanks! That's the deck (link) we used to write our first two Bobcat stories. The above diagrams come from a totally new presentation that should be available on the DOE website by September. :-)

I really believe by 2016, any engine that relies on a gasoline gashog motor should not be used. I just dont like the idea of using a, what seems like fairly normal, V8 under normal conditions. IMO that is still using too much gasoline.

If the whole motor could use e85 it would be much more realist idea.

So even if the Bobcat engine design can meet 2016 fuel efficiency standards, that's not good enough for you? Hasn't it become clear by now that E85 isn't a good option for nationwide fuel purposes because we can't produce that and enough grain to feed everybody?

I know Ford In Australia sell dual fuel and dedicated LPG engines already for cars and utes and are working on an increased efficiency setup for LPG with Orbital engineering in Western Australia

@Huneycutt: Ethanol booting *does not* use E85 as the primary fuel. It only uses small amounts, varying by load, to prevent knock. In city/highway driving the amount of ethanol used would only be about 1 percent of the total fuel mix. That 1 percent could translate to a savings of 5 gallons of gas for every gallon of E85 burned. In a way, it's much better than the flex-fuel vehicles we see on the road today. And hopefully by 2016, cellulosic ethanol will be viable from waste materials. can't even get spark plugs right...this is far too big of an undertaking.

I guess the "new" Ford likes to pay out warranty claims on the junk they build.

This sounds an awful lot like the 1962-1963 Olds F85 with turbocharged engine.They used a jar of alcohol to prevent detonation and cool the engine.When the jar ran out,drivers never refilled it.It was considered a pain and when the A-body intermediates came out for 1964,the turbo F85 was gone.

Please bring it to market, apply it in small and mid-size cars and CUV's, thats going to be the biggest market.

I'll bet it will never see the light of day!

What do we have to look forward to in 2011? I want to buy a 2011 model and then by 2016 rolls around I will be ready for the Bobcat. But what about 2011?

The engine will be well received. Lower cost, less weight, and better mileage. Ethanol is a good fuel. I would think the best place for ethanol would be trucking. Ethanol burns more efficient with high compression and turbo engines much like diesel. Fords Bobcat engine could as easily run pure E85 with no regular unleaded. We should be developing pure ethanol engines or better yet hydrous ethanol. The large vehicle market should be fueled upon natural gas and ethanol. This a better mix for the large semi's. Having dual fuel capabilities or triple fuel with diesel. Those commercial fuel stations a good place to set up hydrous ethanol pumps and natural gas.

@max reid

It´s already in the limelight.
from AWK

Under a shroud of secrecy, Ford, AVL and Ethanol Boosting Systems (EBS) of Cambridge, Massachusetts, working with the US Department of Energy, are testing an engine called Bobcat. Five new ‘ethanol boost’, twin-fuel turbocharged engines have been built and each variably blends gasoline and ethanol to produce diesel-like performance.

Water injection would be better and much cheaper for the consumer.

There wont be anething new in 2011. Just the same old same old garbage from Ford!

Hope this engine comes in many other vehicles, not just Ford's trucks. It would be great in their SUV's and, if it makes as much horsepower as it is said to, they should have it in the Mustangs too. They should try it with much bigger engines because it sounds like with the limit of the E85 will keep it from going under the hoods of bigger trucks. If they could get it so the greater load did not effect it as much, we could see this system in all Ford vehicles. We'll have to wait and see.

Well all you critics can say what you want, but we have to try every avenue to help reduce fuel consumption and everybody cannot drive an electric vehicles. Vehicles that have to really haul a load, need the power that only fossil fuel provides, at this point in time. As soon as you critics can provide better battery technology, I will be ready for an electric myself. Really though, do any of you really think power provided by coal fired power plants (electricity for your batteries) will reduce co2 emissions? Yet, I do not see any advocacy for nuclear power among you, so Ford is going they only way they can to produce higher efficiency engines -- higher compression.
Just stand back and watch -- they are probably on the right approach at least for the short term.

Speaking of Garbage you"re Driving one (TundraRob) LOL Hey Scott get ready for the Boss 6.2 and the Coyote 5.0... All those Boys think about is 0-60 who cares!!! Ford does the Job !!! Good work Ford....

Horrible system.
First off E85 is only E70 in winter.
Why not use direct injection gasoline AND direct ethanol injection? [Use an addition central injector, next to spark plug, like BMW]
and if it is brought to market as flawed as it is, who does Ford think they will sell it to, diesel people? Think again.

Ford should take the cost effective route, upgrade to the ZF 8 speed automatic immediately. Then see what Hyundai is going to do, large engine + supercharger + a cylinder idling system.
Then copy that.

Hey "TundraRob" apparently you didn't hear that the Euro based Focus and Fiesta will be coming stateside in 2011, as well as more usage of EcoBoost motors and not just V6 ones either. There will be plenty to choose from Ford in 2011 with a lot of change into new powertrains.

BTW, the SAE paper # about this engine is 2009-01-1490 if anyone wants to read that oo.

I hope Mike Levine posts more stories on the 2011 engines. I want to know more about the 5.0, the 6.2 and the EcoBoost.

TurboCharging = Idiocy, SHEER IDIOCY.....!!!

TurboCharged engines run in detuned/derated(***) mode 98% of the time, sacrificing FE the clear majority of the time for the FEW times extraordinary HP/torque is required.

Off-boost static compression ratio must be 30 to 50% lower than optimal in order to accomodate the dynamic increase in CR as the turbo spools up to FULL boost.

Use an engine/electric driven (Toyota's HSD e/CVT technique) positive displacement SuperCharger to replace the current engine throttling method and VVT-i to vary the Static CR (15-16:1) from 12:1 (DFI) to as low as 8:1 as the SC boost level rises.

Low engine load, no boost, Low cylinder charge level, 15-16:1 CR, "standard" Otto cycle mode. STELLAR FE..!!

Moderate engine loading, low boost, 12:1 compression ratio, Atkinson cycle mode.

High engine loading, HIGH boost, ~8:1 compression ratio, MILLER cycle.

Power stroke expansion ratio remains 15-16:1 throughout.

The ethanol boost engine is similar to Ricardo's modified GM 3.2L direct injected turbo blown ethanol optimized engine except that the Ricardo does not require separate fuels. It runs on any combination of gasoline and ethanol with no operator adjustments. In both cases the higher octane and higher heat of vaporization of ethanol are utilized to allow higher compression to gain efficiency. Today's flex fuel engines are just gasoline engines that can burn ethanol but ignore the advantages of ethanol fuel for efficiency.
The Ricardo 3.2L produces almost the same power and torque as the non chipped 6.6L duramax diesel (roughly 350 HP and 600 ft lb torque burning E85) but is much less costly to build and weighs just over half as much. The engine is most efficient with high ethanol content but any mix works well. This design can be scaled to power everything from minis to heavy duty pickups.

I think Ricardo's approach is more likely to succeed in the marketplace since it avoids the hassle of dual fuels which many drivers may ignore and just run gasoline. As these engines come into the market the ethanol industry will adjust to supply more ethanol. There are dozens of plants just waiting for market improvement to restart and nearly 100 are planned and could come on-line in time to meet demand as it grows.

The idea that ethanol from grain caused the big runup in food costs is bogus. It was the huge increase in oil and the runaway economy that did it. Ethanol only uses the starch from grains. The remaining high protein portion is sold into the animal feed market where it replaces most of the grain diverted to the ehananol plants. Using domestic ethanol displaces imports from unstable contries that hate us and sponsor terrorist and fund them with our dollars for oil.

Navistar is now effectively a Ford competitor.

The next step in IC engines might be here before 2016: Camless engines. Camless gives high expansion ratio without high compression, Miller/Atkinson/Otto cycle changes on demand. Couple this with cellulosic/gas process alcohols [higher octane, more oxygen, higher latent heat of vaporization] and 200ft/lbs per liter becomes easy.
The question now becomes will Valeo or Sturman be the first vendor to get a system into a mass-produced engine?

The future of ICE engines is going to be what is known as a combustor engine. It will be a inline cylinder block with a combustor like that used in jet engines. The stroke and bore will be less than half that used in current ICE. The engine will be turbocharged. Instead of the piston drawing in the air/fuel charge it will serve as a valve blocking off the exhaust port which is located in the cylinder bore.

An animated version can be seen on youtube

@TubdraRob I bet you don't feel so smart now that it's 2011...

i am so glad this internet thing works and your article really helped me.

Wow. Guess no person to comment on this is in the engine industry......... Ethanol is bad in every way. Makes the vehicles cost more due to the tech that goes into Ethanols inherent trait...... drawing moisture. Makes gas cost more, I personally miss the days of 10 corn on the cob for a buck, and if the USA really wanted to fix emissions we would put a 10 year limit on the age of tractor/trailers, and railroads while we are at it.

I think isobutanol is a better answer.........

Vehicles that have to really haul a load, need the power that only fossil fuel provides, at this point in time. As soon as you critics can provide better battery technology, I will be ready for an electric myself.

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