Mercedes-Benz unveiled a new engine they've been working on. It runs both as a regular spark ignition engine and compression ignition engine, depending on the load. Here are some specs on their F700 concept car that is running this experimental engine, helped by an electric motor.

Weight of car: 3700 lbs
1.8 liter engine
238 hp (132 hp per liter!)
295 ft-lb torque (162 ft-lb per liter!)
44 mpg (on the European urban cycle)

0-60 in 7.5 seconds



The technology is pretty complex though and they say it wouldn't be production ready for at least 5-7 years. GM is also working on something very similar but less complex (they're not varying displacement by moving the crankshaft).

http://www.edmunds.com/insideline/do/Features/articleId=123274#5

[Edited on November 7, 2007 at 1:28 PM. Reason : d]

11/7/2007 1:28:26 PM

multifuel engines aren't a new thing at all. it is cool to see the technology being refined into something that could be mass produced in a new vehicle though.

11/7/2007 1:44:43 PM

No its only going to run off gasoline. No diesel fuel.

11/7/2007 1:53:19 PM

So, it’s adjusting the compression ratio by changing the quench height? I wonder if a less complicated system with variable forced induction would work. But, I guess it would only adjust the dynamic compression ratio.

11/7/2007 2:36:29 PM

hahah bbr silly goose it only runs off one fuel.. it just fires 2 different ways.

this is good technology i've always wondered why no one made a motor that would intentionally run a diesel cycle off of gasoline... i mean i know its more violent but there is also a lot more power available.

11/7/2007 3:38:05 PM

because you cant get a high enough octane rating

11/7/2007 3:48:12 PM

doh, i didn't even read all of it. so the only thing "diesel" about it is the compression ignition.

11/7/2007 3:56:27 PM

no shit.... maybe they call that dieseling for a reason when an engine runs without spark.
it was a thermodynamic cycle before it was a fuel.



[Edited on November 7, 2007 at 4:10 PM. Reason : .]

11/7/2007 4:08:38 PM

I guess we won't be finding a new means of propulsion any time soon then...

11/7/2007 4:16:25 PM

Quote :

"because you cant get a high enough octane rating"

What sets diesel fuel apart from gasoline is its ignitability. And octane rating is actually an index used to quantify resistance to ignition. What we want in a diesel engine is the exact opposite of what's desirable in a gasoline engine. We want extremely ignitable fuel with little lag in flame front propagation in a diesel engine (which is one reason that most diesels have a much quieter exhaust note than their gasoline counterparts; combustion has, for the most part, completed at time of exhaust valve opening and cylinder blowdown). We want resistance to spontaneous combustion in gasoline engines to prevent preignition and detonation.

Diesel = cetane rating
Gasoline = octane rating

They are at opposite ends of the spectrum.

11/7/2007 4:19:34 PM

Quote :

"maybe they call that dieseling for a reason when an engine runs without spark"

actually, that has absolutely nothing to do with compression ignition.

11/7/2007 4:25:54 PM

hey... its the rednecks that said it i'm just using their saying to make a point.
but w/o a spark or heat source of some sort you have to use compression to ignite.

really you make some horrible points on dumb technicalities when you say something stupid and try to back your way out.

11/7/2007 4:40:55 PM

i'm not backing out, i said i didn't read the whole thing and i made a wrong assumption.

for someone who makes stupid/wrong comments on a regular basis then skirts the issue when you get called out, you have no room to talk. at least i can admit it.

11/7/2007 4:55:34 PM

i thought what they were doing here was using direct injection tied with sensors in the combustion chamber to create an extremely lean burn engine. which directly correlates to better gas mileage?

they are able to adjust fuel spray patterns infinitely and harness MSD and all that. things that are lacking on cars in the present.

correct me if i'm wrong.

[Edited on November 8, 2007 at 2:37 AM. Reason : also if what i'm saying is right, the ideas and all are old as shit.]

11/8/2007 2:35:45 AM

EUROPEAN

URBAN

CYCLE

[Edited on November 8, 2007 at 3:38 AM. Reason : i didnt read shit but how are they going from SI to CI, summarize]

11/8/2007 3:37:11 AM

The crankshaft is mounted in eccentric bearings, allowing them to dynamically adjust the quench height and compression ratio. High CR for low load (compression ignition) lower CR for high load (spark ignition). I think that, along with a bunch of other fuel control stuff makes it work.

11/8/2007 7:35:42 AM

[old] duece 1/2's could run on flexfuels 70 years ago

11/8/2007 8:28:45 AM

More like 40-50 years ago.

And the Continental multifuel engines actually had two sets of cylinders.

'scuse me. They've had SOME that had two sets of cylinders. The newer Continental multifuel engines actually would run off of kerosene, JP-8, or diesel. Not gasoline to the best of my knowledge. Hell, Cummins certifies the C8.3 to run off of Kero, Jet A, JP-8, Diesel, etc. You can run the older engines on these fuels too, but you have to add lube oil to the fuel.

[Edited on November 8, 2007 at 9:04 AM. Reason : blah.]

11/8/2007 8:50:58 AM

^^It's not running on different fuels, just gasoline with two different sources of ignition.

11/8/2007 10:41:34 AM

Quote :

"Hell, Cummins certifies the C8.3 to run off of Kero, Jet A, JP-8, Diesel, etc."

are you fuckin serious>? i think that's cool as shit. makes me want one right now. not that i have jet-a lying around or anything.

but kero and diesel? sweet. does using kero affect the longitivity of the engine?

Quote :

"The crankshaft is mounted in eccentric bearings, allowing them to dynamically adjust the quench height and compression ratio. High CR for low load (compression ignition) lower CR for high load (spark ignition). I think that, along with a bunch of other fuel control stuff makes it work."

so fuel ratio of 30:1 to 40:1 or so. the new spray patterns also cool the charge instead of the intake runners, like in designs past. i am so down with the new technology, but it'll make it quite complicated to repair on your own.

i've noticed that every time we have a gas issue, the car companies come up with a new concept on old fuels.

[Edited on November 8, 2007 at 11:08 AM. Reason : f]

11/8/2007 11:08:19 AM

How about this for modified engines?
http://www.fastcompany.com/magazine/120/motorhead-messiah.html

Quote :

"Goodwin leads me over to a red 2005 H3 Hummer that's up on jacks, its mechanicals removed. He aims to use the turbine to turn the Hummer into a tricked-out electric hybrid. Like most hybrids, it'll have two engines, including an electric motor. But in this case, the second will be the turbine, Goodwin's secret ingredient. Whenever the truck's juice runs low, the turbine will roar into action for a few seconds, powering a generator with such gusto that it'll recharge a set of "supercapacitor" batteries in seconds. This means the H3's electric motor will be able to perform awesome feats of acceleration and power over and over again, like a Prius on steroids. What's more, the turbine will burn biodiesel, a renewable fuel with much lower emissions than normal diesel; a hydrogen-injection system will then cut those low emissions in half. And when it's time to fill the tank, he'll be able to just pull up to the back of a diner and dump in its excess french-fry grease--as he does with his many other Hummers. Oh, yeah, he adds, the horsepower will double--from 300 to 600. "Conservatively," Goodwin muses, scratching his chin, "it'll get 60 miles to the gallon. With 2,000 foot-pounds of torque. You'll be able to smoke the tires. And it's going to be superefficient.""

11/11/2007 10:47:48 AM

winner

11/11/2007 2:14:41 PM

Quote :

". "By the time I made it home, after three roadside repairs, I pretty much knew that the Hummer was not all it should be," he told me. He didn't think much of the 200 horsepower engine, either, which did "zero to 60 in two days. It was a piece of junk.""

haha

11/11/2007 2:48:10 PM

Quote :

"are you fuckin serious>? i think that's cool as shit. makes me want one right now. not that i have jet-a lying around or anything. but kero and diesel? sweet. does using kero affect the longitivity of the engine?"

a diesel will run off damn near anything halfway flammable. transmission fluid, used oil, etc... alternative fuels don't have much of an effect on mechanical diesels, but they can pose problems on lift/injection pumps, injectors, etc. on newer electronic/di stuff.

11/11/2007 5:09:22 PM

I used to dump about 2 gallons of waste oil in the tank when I filled up the SuperDodge. She'd lope a little bit at idle, and smoke a lot, but would still pull like a mule.

11/11/2007 5:33:47 PM

Is there any finished example of godwin's work? like another car with supercapacitor batteries and stuff that actually works, instead of being in pieces in his shop?

11/11/2007 5:41:05 PM

Several are mentioned in the article.

11/14/2007 2:54:33 PM

^

thing is that there isn't an example of high technology applications on his side.

just hydrogen injection and converting gas to diesel/biodiesel.

he has yet to accomplish anything using supercapacitors.

[Edited on November 14, 2007 at 5:31 PM. Reason : i don't mean to sound like i'm bashing the guy, but i want his stuff now.]

11/14/2007 5:31:34 PM

^Honda built a hybrid with supercapacitors in conjunction with batteries. Others are working on the same technologies. Sometimes they are called ultracapacitors. Try a google search.

Supercapacitors are pretty cool with their high efficiency, power-to-weight ratio, durability and rapid charging capability, but they are horrid in terms of energy to weight ratio.

Kind of like a small electrical flywheel used for load-leveling, they can store and unload large amounts of electricity for short bursts but they're not solutions for sustained power storage and supply.

[Edited on November 14, 2007 at 6:11 PM. Reason : 2]

11/14/2007 6:10:04 PM

^^ gotcha, i thought you meant examples of finished work in general.

Hell, i think part of the beauty of what he does is the fact that he's mostly using standard GM factory parts.

Quote :

" As he points out, his conversions consist almost entirely of taking stock GM parts and snapping them together in clever new ways. "They could do all this stuff if they wanted to," he tells me, slapping on a visor and hunching over an arc welder. "The technology has been there forever. They make 90% of the components I use." He doesn't have an engineering degree; he didn't even go to high school: "I've just been messing around and seeing what I can do.""

11/15/2007 4:16:39 PM

i agree. i find that gm's steadfast refusal to even consider using off the shelf parts is a sign that they won't last much longer.

i would love a biodiesel/veggie oil suburban with hydrogen injection.

[Edited on November 15, 2007 at 11:07 PM. Reason : e]

11/15/2007 11:05:42 PM