The future of the engine as we know it 1

[franzh]

I normally run like crazy when someone asks me questions about a "new" engine, but when one of my directors asks me to evaluate a "new design" design, my knees shake. That happened this morning.

We have seen free pistons, opposed oscillating pistons, scotch yoke pistons, toroidal blocks, ball valves, sliding sleeves, and tons of other combinations. Strangely, or not so strangely, none of these has ever reached any significant success. The old, inefficient Otto cycle engine still hangs around. With the exception of sealing refinements and air-fuel metering, almost nothing has changed in 100+ years, not including OHC engines which is a refinement, or phased cams, also a refinement, or exhaust aftertreatments, which is not a refinement, but an attempt at fixing an engine inefficiency.

I wonder how long it will take before something else pops up and takes a reasonably strong stand against the tried and true engine design?

Lets look at the true IC engine replacement, not hybrids (although I feel that is where we are heading for the next 25 years). Turbines are nice but not practical for a number of reasons.

When we look at H2 as a potential fuel, it still uses the Otto cycle engine as a base, only the fuel has changed. Are we really gaining anything on the engineering side? I recognize the significant advantage on emissions, but fuel transport, storage, and infrastructure have still to be perfected.

Any ideas, fellow engineers?
Franz


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[franzh]

Jay;
All good points. In 1980 I attended an advanced automotive SAE Toptec workshop where technology was discussed, presumably for the next 20 years.
One presenter was there who was trying to market a ceramic engine, or an engine with a significant amount of ceramic and/or composite components. He discussed using ceramic cylinder head inserts to retain the heat in the combustion chamber (Detroit Diesel and Cat both experimented with them I'm told), cylinders made of a ceramic that would not wear that were honed with a diamond dust tool.
Plasma ignition was not especially targeted at longevity, but at an extremely hot discharge, igniting all of the fuel mixture.
One presenter demonstrated an ultrasonic grid that was installed below a conventional carburetor body that vaporized the gasoline so fine as to turn into a cloud. Not those hyped mini-superchargers that install in 30 minutes and cost $38.95, in the back of hobby magazines.
The ultra capacitors are practical, and there are cars today that are starterless and alternator free, (at least as we know them) with the components mounted in the flywheel.
Now, as we have seen, Buck Rogers flying suit never materialized, but we have automobiles that are levels of magnitude cleaner and more efficient today than 30 years ago, and the cars of 200,000+ miles are normal, not the rare exception. I firmly believe we can thank the emission requirement warranties for that push. We have succeeded there, but what's next?
Franz

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[evelrod]

Pat, your a brave man. Let us know how THAT idea turns out.

The "stinky" reference was a euphemism. The fuel in California is so sulpher free as to be nearly "non stinky" anyway. I simply ment that it's going to take more than technology to convert the American driving public to diesel power. It can be done, certainly, but not without a massive publicity campaign. American drivers have no idea of what they want unless they "see it on the telly"!

Rod

 

[JayMaechtlen]

if the starter/alternator are integrated into the flywheel area, (now becomes a motor/generator) it is still there...
Maybe you get rid of the serp belt, maybe you still drive the p/s pump, water pump, and a/c with it.
I know, there are electric p/s systems, etc...
Just need an efficient, high power charging and storage system.
As I understand it, there was an adiabatic diesel engine project some years ago- ceramic everything, and no cooling system. Wast heat was rejected through the exhaust and by convection/radiation.
I wonder what the results were?
cheers
JAy

Jay Maechtlen

http://home.covad.net/~jmaechtlen/

 

[franzh]

Ah, you remember it too! Rumor had it that it was a Caterpillar prototype, a 4 cylinder engine, rated around 90 bhp. I heard that the radiator was the size of a cigar box, or close to a conventional heater core. Sometime in the early 80's. Never saw it, but heard stories by several independent sources.
If a flywheel mounted starter-alternator were used, then all accessories could be remotely mounted, then driven only as much as needed, ie: water pump, air conditioning compressor, power steering, etc. I can see power advantages there.
I had heard that Chrysler was looking into it with their Dakota Hybrid that was supposed to be out last year. A V-6 with hybrid assist on the front wheels, conventional drive to the rears. Wonder what happened to it?
Franz

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[rmw]

I thought it noteworthy to the topic of this thread to note that while watching a show on Fox News this AM called Forbes on Fox, one of the participants recommended the stock of Sasol (SSL) of South Africa, a company that developed a lot of the GTL technology when SA was isolated during apartheid. The stock analyst actually spoke quite intellegently about the GTL concept and Sasol's involvement in some of the current plants being built around the world in his recommendation of the stock.

So, it is not just engineers watching this technology.

rmw

 

[tbuelna]

rmw,

Exxon Mobil just made the largest investment ($7 billion) in their history in a GTL plant in Qatar:

http://edition.cnn.com/2005/TECH/science/05/17/green.gas.ap/

 

[rmw]

Thanks, Tbuelna

I have been following that situation with interest for some time now, as well as the recent news that Qatar just put the slow down on a similar deal with Conoco/Phillips, I think it was. If there wasn't something to this concept, those big boys wouldn't be playing in this ball park, so to speak, hence my original post in this thread earlier.

Even this is an automotive forum, and thread, I think it also has ramifications in any industry that currently uses Natural Gas as a power generation fuel and can easily convert to diesel, and is located where infrastructure exists (ship and barge unloading capabilities, or near products pipelines) for diesel delivery.

For my part, in my younger days, I started up plenty of Gas turbines dual fuel, Nat. Gas and #2 oil fired.

Automotive is, in my way of thinking, ripe to make the initial rapid advances for the first fuel produced by this process.

rmw

 

[Singleseater]

Franz,

Until recently, most advances I have seen in the industry have revolved about extracting energy from a liquid fuel, petroleum based for the most part. The quality of the distillates have improved from years prior but I do not see any great breakthroughs occuring in petroleum distillate technology. So engineering efforts will be guided at more effectively squeezing every ounce of energy from the petrol with as little heat wasted and as few emissions as possible. With the Otto cycle at approximately 28% efficient, there is alot of room for improvement, but new materials or not, we are in the exponential portion of the curve where many R&D dollars spent here will not add a representative gain in efficiency.

So where next? Why make it better at all? The main push seems to be the fact that the petroleum resource if finite and/or the environment is affected by the byproducts of the human transportation process (heat, emmisions). So we need to make a device that transports humans using an infinite, cheap fuel source with no measurable impact to the environment while allowing high speeds and quick acceleration. Oh utopia!

As mentioned earlier, batteries are just not there yet. Lead acid, the bulk of the automotive state to date, is far from cutting edge but reliable and readily available. We can get lead and sulfuric acid rather easily. But what to do when the meriad of batteries need refurbishment or replacement. Petroleum based fuel consumption is down in the hybrid, but the storage of environmentally unfriendly used lead, acid and the plastic battery cases become the problem. If a completely electrical car is the course, then the non nuclear power plants centralize the polution efforts instead of spreading them to the individual vehicles. For an environmental system, the pollution is not appreciably less over time.

So that leaves alternatives such as fuel cells and solar power. Fuel cells presently have more promise near term, but I predict that eventually solar cell technology will be the winner combined with fuel cells. Solar during daylight hours and fuel cell at night. Recycling will come into play with hybrids to slow the battery issue as better batteries are produced, but with all of these, the consumer will not be happy with a mode of transportation that achieves 0-60 in 25+ seconds or a system with a maximum speed of 40 MPH. Thus the main reasons the Otto cycle is still around .... vehicle provides the individual the ability to go where they want, when they want, quickly at a relatively low cost.

I ask what are the alternatives if petrol were to disappear tomorrow? That is the longterm (100+ years from now) we should be exploring now.

My .02 cents.


Brian Barnett

 

[franzh]

Brian;
I couldn't agree with you more!
I see a renewed push for the diesel engine (here in the US, the diesel engine never really caught on with the general public). It's efficient, allows for relatively transparent operation to the consumer, powerful, and not "rocket science". I'm surprised there is not more interest in a diesel hybrid for the consumer market. Ford was looking at a hybrid Taurus around 1998-2000, but it never materialized.
My thoughts on the disappearance of petroleum products? Probably within our lifetime, exponentially more acute after 2025.
What do I see as an alternative? OUCH! Try to retrain the American public in living and working communities, mass transit, rely less on travel, and so on. The list appears endless. I really do not see a drop in replacement for fossil fuel, it all comes from the same place.
Franz

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[tbuelna]

franzh,

Turbine engines may get significantly more efficient if the Humphrey cycle (constant volume) combustors can be perfected.

http://www.pw.utc.com/shock-system/takingthepulse.html

regards,
Terry

 

[rmw]

In my comments earlier in this thread, I limited my remarks to GTL progress and possibilities.

Regarding running out of fuel for autos in our lifetimes, as long as we have the proven coal reserves we have in this country and other parts of the world, that is probably not a worry.

Check the following link.

http://www.rentechinc.com/pdfs/WBC-Presentation-4-14-05.pdf

rmw

 

[rdd48856]

In the long term we will need to look for energy from where it all came from on the first place: nuclear fusion. Shame cold fusion didn't work out...

 

[schwee]

franzh/Terry:

It is coming. I should get my compressor/combustor by next week, and send it off for starting and ignition work thereafter. Variable nozzles, etc., reserved for phase 2 testing. The free power turbine and turbocharger are purchased and waiting.

The answers are, in order, HCCI, greatly reduced time for heat to transfer to the cylinder walls; followed by: free piston, gas turbine, true constant volume combustion, lean running, variable stroke, 50:1 compression ratio, Miller cycle, Pescara cycle, very low engine friction, aggressive turbocharging, double-acting 2-cycle combustion, direct in-cylinder fuel injection, zero NOx, tripled torque vs. hp at zero rpm, tripled power/weight, halved manufacturing costs, essentialy maintenance free, runs forever.

No hybrid drivetrain. Runs on unleaded gasoline, around 70 octane or lower. Or kerosene.

Something like that.

Schwee

 

[tbuelna]

schwee,

Sounds expensive. Did you win the lottery?

 

[schwee]

Nope -- I've been working with a partner for the last two and a half years, who knows more about adapting APU-type gas turbines to novel purposes than about anyone I've found. He owns about ten of them, and has donated one to the project. He'll also handle all integration of the free-piston gasifier with the turbine (Allied Signal JFS-100). And provide testing facliities and expertise (yes, he does have some fairly serious resources).

All I have had to do is get the gasifier built, and that's in its final stages. Really quite a small inivestment. Money-wise, anyway. Nothing to it. ;o).

How is your project coming?

 

[globi5]

I don't see how hydrogen (fuel cells or not) could ever play a major role in powering vehicles either. Even if they solve all the distribution, storage and safety issues, diesel will always have 15.6 times the power density per volume of compressed hydrogen.

http://www.osti.gov/fcvt/deer2002/eberhardt.pdf

Why all that brouhaha about hydrogen?

I wonder though whether methanol fuel cells (DMFC) might be able to substitute the IC engine at some point?

http://www.fctec.com/fctec_types_dmfc.asp

http://www.dpreview.com/news/0406/04062401toshibafuel.asp

Currently DMFCs don't reach the power density required to propel a vehicle, but maybe they could in combination with high power capacitors like these:

http://ecl.web.psi.ch/Publications/cap_pub/AABC_2002.pdf

Also, I don't think the gasoline engine is dead yet. Wenko built a gasoline engine with an extremely high power to displacment ratio at relatively low rpms using a pressure wave supercharger. (Less weight and higher efficiency at partial throttle settings.)

http://www.swissauto.com/e/projekte.e/technischedaten.e.jsp?ID_Display=200004

http://www.swissauto.com/uploadfiles/EN_200056.pdf

Besides ethanol can also be used in a gasoline engine. It has a higher knock resistance than gasoline and would therefore allow a higher compression ratio or boost pressure. (Of course, Americans could then say: We grow oil on our own soil. And we fund American farmers instead of some corrupt Kings in the middle east.)

 

[tbuelna]

My project has been moving along slow and steady. I have a development (2.1L, 4-stroke, spark-ignited) engine on the dyno and it's working quite well.

My first patent on the engine was just issued on Sept. 6th. I'm also currently in the process of designing a 350 hp compression-ignited engine.

I'm working on the project full time now. But I haven't yet secured enough money to fully pay for the diesel effort. I have submitted proposals to DARPA/DOD for some research funds, but will not hear back from them for a few months.

Glad to hear your project moved from the drawing board to lab.

 

[thundair]

No one has mentioned vapor recovering engines. Did they fall by the wayside?

I worked on a 300HP model for aircraft of all things thought it would make a nice generator

 

[franzh]

One thing to remember gents (I assume so) is that no engine is 100% efficient.

In a recent lecture, one audience member challenged me to a series of technical questions.

When he posed that his engine was 80% efficient, I asked if he had ever burned his hand on the exhaust manifold, he replied "yes, several times". Hmm, exhaust radiant heat.

When asked if he was using a radiator, and at what temperature the coolant was, he replied "Just about what a typical car runs". Hmm, coolant radiant heat loss.

When asked if he had a transmission, tires, driveline, and engine accessories, he stated that those were necessary, and the same answer when asked if the engine had pistons, rings, camshaft, valves, oil pump, and coolant pump.

We are getting pretty good with the IC engine as we now know it. Only a very few engines are able to break the 30% range for motor use, and the upper 30% for OTR CI engines.
Turbine applications have more theoritical effeciencies, but as long as there is waste heat, there is energy loss.

Is the answer recovering the waste heat and totally transforming the thermodynamic capabilities of the fuel to usable energy?

Franz

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[globi5]

I'm not an expert but even if you can recover all the waste energy I don't believe that any engine could ever surpass the efficiency of a combined cycle power plant which I think is around 65% max. (The larger the engine the inherently smaller are the frictional and heat losses):

http://www.power-technology.com/projects/san_joaquin/san_joaquin3.html

Diesel engines in passenger vehicles already reach 45%, so there's not much to gain anymore unless we switch to fuel cells (which don't generate a lot of heat in the first place).

I think the answer is (which is partially taking place anyway):
* Making the car (and its engine lighter) and reduce drag. (Why do we need a 3500 lbs. vehicle to transport 250 lbs. on average?)
* Recycling brake energy.
* Make the engine more efficient particularly at partial throttle settings. (I think I drive about 90% at partial throttle).

I just realized that I should have said energy density of diesel vs. hydrogen and not power density in my previous post (but I can't edit the post).