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

pickuptrucks.com ^ | June, 8th 2009 | Mike Levine

[taildragger]

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.

[taildragger]

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.

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.

[Crolis]

Thanks for posting. This is facinating. Ford seems to be positioned nicely to bring some nice technology into the marketplace.

[taildragger]

BTTT....

[domenad]

Freaking awesome! I bought Ford at $1.95 just to use up the spare $30 in my account. I wish I had bought a thousand shares.

[Army Air Corps]

Ping.

[Brookhaven]

The gasoline and ethanol would be stored in two separate fuel tanks.

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Isn’t one of the problems with ethanol that it is very hard to handle (as in catches fire easily) in its pure form?

Also, two fuel tanks means two fuel caps. What will prevent your typical soccer mom from putting ethanol in the gas tank (and gas in the ethanol tank)?

Neat idea though.

[taildragger]

Crolis,

It is fasinating. "Ricardo" is working on straight E85 DI with equally crazy gobs of torque. They call their system EBDI I believe.

Either way the "Diesel Ping List" will go crazy, but both efforts might say to the Diesel, bye-bye.....

[JWinNC]

all that added complexity to get less than 20mpg?

might as well stick with diesel

[Gandalf_The_Gray]

Very interesting, it looks like someone has finely figured out the only proper use for ethanol in an internal combustion engine. Hats off to Ford, this looks very promising.

Regards,
GtG

[taildragger]

Looks like the system would run without it with a perforamnce downgrade.

Just wait until soccer mom gets home and go fuel it yourself and get a "Cherry Coke Slushy", while your at it. :-).....

[DieHard the Hunter]

First, I wonder how they manage to prevent the engine from running too hot.

Second, with higher compression ratios and a much more explosive air/fuel mixture, I wonder how they manage the inevitable need for more maintenance on the heads and head gaskets.

Doubtless Ford will have all of this figured out nicely: they’re pretty clever. It would be interesting to see how.

[lafroste]

No, No, NO, It CAN’T meet the CAFE standards. The purpose of the standards is to force cheap, foil made death traps. This could meet the standards while keeping the heavy metal, therefore, the CAFE standards will have to be raised until this engine can’t meet them.

[Abathar]

"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."

I guess if you live out in the mountains or are using it for heavy work it might not be practical, stick with a strait diesel.

For the weekend warrior who goes to Lowes or pulls a boat a few times a summer and commutes with his truck during the week it seems to be practical though.

[Gandalf_The_Gray]

An added note:

Direct cylinder injection requires that the substance injected be pressurized to something like 1000 to 1200 psi. Port injection uses much lower pressures (100 psi or less). The requirement for higher pressures makes for some tricky material selections for the injection pump. Diesel injector pumps work with hardened steel because the fuel has good lubricity. Alcohol is a very "dry" fuel and has very low lubricity and gasoline isn't much better. The injection pump has to meter very small quantities of E85 at high pressure, this suggests very tight tolerances and very hard (wear resistant) materials. It won't be cheap compared to the gasoline only systems in current use. However, if they get it working properly it'll be worth it.

Gandalf

[Kenny Bunk]

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,

"Diesel-like Performance" Indeed, what Liberal Arts Green Weenie Grad wrote that BullShiite?
This is a spark engine that runs on ethanol or gasoline. Big whoop. Double big whoop with the big tax on important Brazilian ethanol.

This is still part of the ethanol craze, when we have billions of barrels of barrels of crude beneath our feet and every Euro car maker is already making small clean diesels that get upwards of 50mpg. You can buy one right now at your VW dealer. If Chrysler can get them, from FIAT, they can compete. Imagine a beautiful small SUV that can get 55mpg on diesel for 15 Gs.

This is also part of the Green Weenie Craze to never allow Diesel passenger cars into the United States; PROBABLY the direct result of having been frightened in utero by a MB 190 D emitting a cloud of smoke on a frosty morning in 1947.

As a result of "boutique fuel rules" Diesel is now as expensive .. or more ... than gasoline, when it should not be, requiring much less energy to refine.

Good post. But let's tell Ford that their Bobcat is based on pussy-tech AND THE RIDICULOUS ETHANOL PREMISE.

When the corn crop is converted to ethanol, tortillas will hit $5.00 each. expect our illegal Mexican aliens to riot in the streets OF YOUR TOWN.

[Jeffrey_D.]

“Freaking awesome!”

Indeed ! I did and now I wish I could have risked even more !!!
Nothing like more than tripling your bet in 3 months.

[Balding_Eagle]

therefore, the CAFE standards will have to be raised until this engine can’t meet them.

Right on. Can't have emissions tests that can be passed.

[OpeEdMunkey]

Also, two fuel tanks means two fuel caps. What will prevent your typical soccer mom from putting ethanol in the gas tank (and gas in the ethanol tank)?

Good point.

Different sized fuel filler neck inserts? Actually it would have to be different shapes since different sizes only protect in one direction. That in turn would require some kind of pump nozzle retrofit.

Ah what the heck. It's only money. Interesting technology though.

[MHGinTN]

You obviously have never had one of my special martinis ... “Very interesting, it looks like someone has finely figured out the only proper use for ethanol in an internal combustion engine.”

[VeniVidiVici]

Seems to me that a 5.0L V8 with twin-turbos could probably get 500hp regardless of whatever voodoo switches between varying mixtures of ethanol and gasoline.