Still ROFL!

 

I found it funny, I was just too lazy to comment.

 

Another piece (or two) of the Smokey puzzle: He understood that 'normal' engine materials could not work with his abby-normal engine (Yes, a "Young Frankstein" reference - I couldn't resist.)

Mr. Yunick had a column in Popular Science (PS), back in the 80's, and I was a fan of his because of his work with Pontiac and the original Super Duty engines (61-63) as well as their NASCAR involvement; so I read his automotive advice with great interest.

Anyway, according to Popular Science, which did a 4 or 6 page cover story on his 1984 3 cylinder turbo Fiero, various portions of the engine were actually machined (using diamond cutters) out of solid carbide, as to withstand the extreme temperatures without failing. (I did not read that fact in the latest Hot Rod information, so I thought it should be pointed out.)

Additionally, PS was quite rigerious in its testing of Smokey's car. They wanted to fill it with "regular" unleaded, and Smokey insisted on using a special type of gasoline that the car companies used (at that time) when performing their mileage tests; so, they compromised and ran it both ways. It ran fine when using the 'special' fuel, but did indeed detonate when using regular 87 octane pump gas. (Having said that, I would NEVER put 87 octane fuel in MY turbocharged LT1, as it too would detonate.)

Anyway, PS thought the vehicle was an interesting 'engineering concept', but they thought that a solid carbide engine block, which Smokey wanted to make for his next prototype, thereby eliminating the cooling system altogether, would be far too cost prohibative and difficult to mass produce.

[OK, now all of you KIA's can tell me how I'm an idiot and I didn't actually read what I read back in 1984, in my high school's library, before becoming an Mechanical Engineer; and the rest of you can ignore them and rationally discuss this additional information.]

 

Reduced conductivity would raise thermal efficiency. But, carbide is expensive and tough to work. It also weighs twice as much as iron and almost six times as much as aluminum. The money spent to make a single carbide engine could be better spent on gas for many regular engines.

 

I'm new here, and just registered because I wanted to see if I'm missing something. Also, I'm not an engineer, but the way I see it is:
On EFI system, vaporize the fuel with heat exchange between exhaust pipe before entering the combustion chamber and change the timing to TDC because you don't have to compress the gas to vaporize it. So, the more of the combustion is directly applied the the kinetic motion of the piston, instead of heating up the combustion chamber. Also, no pre-detonation due to TDC timing. But you probably will have to have higher injection pressure to maintain a somewhat compressed gaseous state (maintain some density) to avoid power loss due to overall less fuel mass.

 

Flame travel still takes time to reach the piston, which means spark must occur BTDC.

More fuel could be saved if the engine that was able to achieve higher BMEP through possibilities afforded by lower temperatures.

What about autoignition ATDC?

More fuel injected won't change the reduced air intake.

 

I'm not saying your explanation was wrong but chill out the guy has 1 post.

 

I don't care how many posts he has, it's unacceptable to play pretend smart and throw out idiotic ideas that will inevitably confuse people legitimately looking to learn.

 

There is some interesting thoughts expressed above, and some not-very-helpfull and somewhat assinine statements made as well.

I have been doing some research on the Smokey Yunick Adiabatic Engine, as I am wanting to attempt to duplicate some of the results claimed (and documented) in multiple sources, regarding multiple engine & vehicle configurations.

I have a fair grasp of technological concepts, some college education in mechanical engineering, observational experience of working at a small automotive repair shop that covers nearly all types of repairs, and personal experience of repairing my own vehicles (currently Toyota R engines, past mazda Rotaries), among the odd orphan make and model.

My understanding is as follows:

CURRENT TECHNOLOGIES are not MAXIMUM FUEL EFFICIENT. Guneas Book of Records is something like ~ 900 MPG.

CURRENT R&D TECHNOLOGIES can achieve ~DOUBLE OEM MPG's.

Smokey's approach is docuemted to do just that, and also significantly increase power.

How?

PART of the recipe is known, and/or documented publicly.

Why?

Everyone has their opinion. Those in the KNOW (ie, the Yunick Family and close freinds) have VERY PRUDENTLY chosen to SMILE and KEEP THEIR MOUTHS SHUT.

PATENTS do not dissallow people from duplicating a specific item FOR THEIR OWN USE, or from FILING A PATENT WITH A SIGNIFICANT IMPROVEMENT.

So, without further ado, my next post will be

MY PERSONAL UNDERSTANDING OF THE IMPLEMENTATION OF THE YUNICK CONCEPT.

(Sorry if I come accross as yelling- I wanted to emphasize the UPPER CASE items)

 

Now, for the HOW (my understanding)

1.) CARBURETED SYSTEMS ONLY. No fuel Injection. Period.

2.) COOLANT PREHEAT. 'Wet Fuel/Air mixture is heated to less than the boiling point of the coolant; Max. Temp ~ 212 Degs F +/-.

3.) MILD BOOST/TURBOCHARGE. Sources claim ~ 1 PSI Boost. Sources also emphasize the the MAIN FUNCTION of the Modified Turbocharger (Sources call this devise a 'HOMGENIZER' is to allow MIXING, EXPANSION OF THE FUEL COMPONENT OF THE MIXTURE, and SECONDARY PREHEATING of the FUEL/AIR Mixture (to ~ 450 Degrees F.)

4.) ENGINE GEOMETRY is modified (according to Sources), such that PISTON DWELLS @ within ~ 0.001 of TDC for ~ 13 degrees of Crankshaft Rotation. My understanding that this translates into LONGER ROD:STROKE ratios.

5.) IGNITION is conventional SPARK IGNITION; Timing is one of the unknowns. Same for VALVE TIMIMING and CAMSHAFT SELECTION.

6.) EXHAUST is a conventional TURBOCHARGER type (aka, 'Homogenizer'

7.) SMOG & EMISSIONS. Sources indicate that EGR should be included.

So, There is the RECIPE.

*Note* This would be a 'Draw-Through' Carbureted Turbocharger Set-Up

 

Now, for the WHY (My theory)

NEARLY ALL 'super-carbs' operate on a VAPOR FUEL PRINCIPLE. This is on the theory that the BEST POSSIBLE MIXTURE involves a GASEOUS FUEL (maximum possible atomization/division).

Obviously, a better mixture will produce more efficiency and power, related to surface area and chemical reaction rates, with available reactants.

Wood blocks burn slowly. Sawdust burns less slowly. A cloud of sawdust & air in a confined space explodes, but the sawdust will settle given time without ignition. A gas leak in a building will not separate, but will dillute given time.

In an engine, with ALL CONVENTIONAL IMPLEMENTATIONS, a LIQUID is divided into fine droplets, which promote evaporation due to increased surface area. naturally, the more volatile components evaporate first, and the less volatile later (or not at all).

LIQUID GASOLINE DOES NOT BURN. Ask any mechanic. FUMES, on the other hand, burn very well.

So, going to the engine. We have an aerosol; liquid globules/droplets/mist suspended in a FUEL VAPOR/AIR Mixture (3 components; LIQUID FUEL, VAPOR FUEL, AIR)

The COMPRESSION STROKE occurs, temperature increases, and evaporation increases. Also, pressure increase, and phase changes are dependant on pressure. This can cause condensation of vapor phase components. This happens rapidly, so only a partial phase change of the liquid components can occur. THERE IS STILL A LIQUID COMPONENT to the mixture at the time of IGNITION.

IGNITION occurs, Temperature Increases (encouraging further evaporation of the remaining liquid components, and PRESSURE (which makes the power) develops. Timing is usually adjusted such that peak pressure develops just after TDC. The mixture continues to burn the remaining reactants (fuel/air) through the rest of the stroke, even as the pressure and temperature decreases from the expansion during the power stroke (as aditional energy is being extracted to power the vehicle).

Then, the STILL BURNING (!) Exhaust mixture is vented/expelled during the Exhaust Stroke. UNBURED FUEL AT THIS POINT IS WASTED HYDROCARBON EMISSIONS, OR UN-USED ENERGY, Which is not building usable heat/pressure in an engine. SOME of this ENERGY is able to be used to drive a Turbine (ie, Turbocharger), and gain some usefull power (for such things as compressing the intake charge, turning a generator/alternator, what have you), and, of course, the heat can be use in applications where heat is needed (such a cooking, driving chemical reactions, staying warm on a cold day, etc.)

Smokeys setup does several things -

1.) It encourages fuel evaporation BEFORE INDUCTION (Coolant Preheat)

2.) It encourages fuel evaporation BEFORE INDUCTION (Compression Preheat)

3.) In encourages fuel evaporation BEFORE INDUCTION (Exhaust Preheat)

4.) It MIXES the FUEL VAPOR/AIR mixture VERY THOUROGHLY, such that any available fuel is able to find available oxygen eficciently, and that the HIGH and LOW OCTANE components of the fuel are also EVENLY DISPERSED.

5.) This provides for MAXIMUM AVAILBLE COMBUSTION when it is MOST NEEDED, ie, at or near TDC, and NOT AFTERWARDS, in the late power stroke, exhaust stroke, blowdown, catalytic conversion, in the muffler, or atmosphere (ie, slow oxidation of HC emission).

Because MORE OF THE FUEL MIXTURE can burn at this time, and less of the fuel is WASTED by not being burned in the non-productive areas described above, MORE GROSS POWER IS PRODUCED from the same ammount of FUEL.

In fact, probably too much. I believe that the Stochiometric Mixture so often quoted includes the WASTE caused by the ineffective burning of the liquid components, and the WASTE cased by the delayed burning of the late-evaporation of the heavier components.

Thus, a CONVENTIONAL FUEL CHARGE would behave AS IF IT WAS TOO RICH, because, IT ACTUALLY IS TOO RICH.

Adjust to VAPOR STOCHIOMETRIC, which is the same type of ratios as DESTROY YOUR ENGINE LEAN with liquid fuel induction, and you get the same (or better) power levels with less fuel, aka, better mileage.

And THAT is my theory of the WHY.

FYI, another, recent approach, involves ~ 800 degree F SUPERCRITICALL GASOLINE DIRECT INJECTION. The laboratory claims that they routinely DOUBLE the fuel econmy of their FUEL INJECTED TEST VEHICLES on DYNO RUNS.

Same theory as to Why that would work, too.

 

900mpg over a long distance is a feat achieved yearly by high school shop classes.