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Another Henry Smokey Yunick Hot Vapor Engine Thread
3

Another Henry Smokey Yunick Hot Vapor Engine Thread

Another Henry Smokey Yunick Hot Vapor Engine Thread

(OP)
First, I am not an automotive engineer and I didn't spend the night at Holiday Inn. I jumped into this project only a few months ago and had a leg up because I know Danny Soliz very well and he is a life long adherent of Smokey, has studied the HVE and actually has 5 of the 10 known HVEs including the numbers matching Horizon and its engine. Overview: https://www.youtube.com/watch?v=uNLpHGy3fVw Running on a stand: https://www.youtube.com/watch?v=vDL65UUjOss&t=... Discussing cams for the Iron Duke version: https://www.youtube.com/watch?v=NS9serKZ30s&t=...

After having read what was readily available I have gone further down the research trail than most. I was aided by documents from DeLorean's files and other documents and articles from the past. What I have gleaned is that it is a polarizing issue driven by Smokey's legend, myth or infamous reputation. The claims are well know, but there is no proof. My question is this: Would the data pulled from 12 Dyno pulls and 10 road tests of MPG from SwRI be proof? How about reports by engineers at SwRI? Or reports and quotes from someone like Gregory Flynn who ran GM's Motor Division attesting to it working? If those showed approximately the 50MPG, Zero Emissions, 1.8 HP/CI from a 1.3l Engine using a carburetor and other tech available in 1982, would that be enough for people to say it worked?

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

Elsewhere ... https://www.yellowbullet.com/threads/smokey-yunick...

Pay attention to posts 18, 22, 26 ...

Smokey Yunick was the master of keeping his mouth shut. He'd keep some critical aspect of whatever he was doing secret, but without knowing that trick, you would never get it to work. What those secrets were ... in many cases we'll never know.

I suspect that these engines, with sufficient trickery applied, may have been able to pass 1980s-era emission standards without a catalyst and with carburetors, but there is no way they would pass today's emission standards.

With very high-temperature operation, NOx is a concern. With lean operation, lean-misfire is a concern. With high-temperature intake charge and forced induction, detonation is a concern.

Modern direct-injection, variable valve timing, etc address at least some of the issues Smokey was trying to address otherwise, before that technology was production-ready.

Bear in mind that Otto-cycle engines that operate on natural gas, aren't appreciably more efficient or powerful than comparable engines that operate on liquid fuel, nor do they miraculously make NOx emissions magically go away.

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

(OP)
My point is, that from what is available to the public, who knows what is sitting on the shelves at the OEMs, there has been no "proof" of MPG, no "proof" of CO or NOX compliance, no proof of HP. It was all alluded to in magazines or Smokey interviews but no body ever had hard data or 3rd party verification of the claims. Would dyno pulls and contemporaneous reports from engineers like Flynn and Karl Springer lay the speculation to rest. Especially if Smokey was not present for the test and the cars were simple dropped of in San Antonio for days at a time? And, I have read the old post on this thread an a score of others. Not one ever shown or claimed to know what pulls showed or 3rd party verification. Obviously, Daniel Soliz ran one on a stand, the Fiero is shown on the Dyno and the Horizon is shown being driven in the Swedish video, but that just proves that it works, not that it works as has been claimed. So I will ask again, If hard data was available and it showed results, would that be enough? Or does an new prototype need to be built.

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

It would help a lot if there was a scientific theory to explain the physics and chemistry behind any such claims. Anyone can espouse a bullshit explanation for this or that and fake test results, but actual scientific theories are harder to produce and easier to debunk if flawed.

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

I would trust Smokey the way I would trust Penn or Teller in a card game. All of them are/were honest. What's not clear is what they are/were honest about.

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

(OP)
So, @Lou Scannon, What you are saying is , that in my hypothetical: The head of emissions of SwRI and the former head of GM Motor Division offered up bullshit explanations and faked test results? @3DDave same question. If as I stated in the hypothetical, the car(s) were at SwRI for days at a time and Smokey was not present. Then test were conducted. SwRI and a SAE Board of Directors member were part of Smokey's magic and the results from dyno runs and MPG test were fabricated? I am just asking, what entity or persons could provide proof for engineers/scientists that the HVE worked as advertised back in 1982?

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

So, what's the scientific theory?

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

" reports and quotes from someone like Gregory Flynn who ran GM's Motor Division attesting to it working? If those showed approximately the 50MPG, Zero Emissions, 1.8 HP/CI from a 1.3l Engine using a carburetor and other tech available in 1982, " and GM didn't take it any further because they were successfully fending off competition from the Japanese? Pull the other one, it's got bells on.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

Just because you have a patent, doesn't mean it actually works. (I'm not saying Smokey's engine "didn't work" ... just saying, take what it says in a patent, with a grain of salt.)

Just because you have a patent, doesn't mean that patent contains ALL the information that you need in order to make the concept illustrated in the patent, work. (They never do.) Smokey was very good at keeping his mouth shut.

Now, let's scrutinise Smokey's patent linked to above, and compare it to "modern state of the art" - some of which involves engine features that hadn't been developed at that time.

"Background art."

The bit about fuel not getting completely vaporized, first I will point out that modern fuel injection is better at distributing that fuel, and secondly I will point out that engines that run on propane or natural gas don't have miraculously high efficiency compared to those running (properly) on liquid fuel.

The bit about "carburetor double-pull" is a non-issue with port fuel injection, or direct-injection.

The patent is silent about how to control detonation, other than "hand-waving" and saying "it doesn't detonate".

The patent is silent about how to get a normal spark plug to fire the supposedly lean air/fuel ratio, although the patent doesn't really get into that.

So, what do I really think is going on (at least to some extent)?

Smokey was a smart guy. He built lots of high-powered racing engines. He knew a thing or two about compression, and charge turbulence, and the like. I think there was some port-shaping trickery, and some squish-clearance trickery, and perhaps some clever combustion-chamber shaping, to achieve really fast-burn combustion. (Modern engines do this, too.) The advantage of his full-vaporisation strategy is that he didn't have to worry about charge turbulence "centrifuging" liquid fuel out of suspension. It's pretty likely that the spark plugs and/or ignition system contained a few secrets, too.

And the other thing I suspect ... is cam timing trickery. Everyone has heard of the Atkinson cycle, or its forced-induction counterpart, the Miller cycle. Smokey's engine could have been an early implementation of the Miller cycle. Whether he did it by really early or really late intake valve closure, who knows ... I suspect the latter, as it's more compatible with valvetrain designs that were common at the time. Use late intake valve closure to cause the effective expansion ratio to be greater than the effective compression ratio ... use the turbo to compensate for the loss of volumetric efficiency when the driver asks for full load ... machine (otherwise) crazy compression into the pistons and head with really tight squish clearance to get good charge turbulence and a fast burn.

The modern V6 gasoline engine in my driveway achieves the Atkinson cycle upon command by fiddling with the intake and exhaust camshaft timing - the engine has variable valve timing with independent control of the intake and exhaust sides. That didn't exist (in production) in Smokey's era.

I would love to see an independent lab test out Smokey's engines to see what's really going on ... and perhaps a non-destructive look into the combustion chamber with a tiny camera through the spark plug hole to see what he's done with the pistons and the combustion chambers.

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

One other thing. If my suspicion is correct, it's rather likely that modern instrumentation and testing would find Smokey's engine to have high NOx emissions. Slightly lean of stoichiometric + high compression + fast burn = NOx.

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

(OP)
@BrianPeterson: "One other thing. If my suspicion is correct, it's rather likely that modern instrumentation and testing would find Smokey's engine to have high NOx emissions. Slightly lean of stoichiometric + high compression + fast burn = NOx"

From the DMC memo from Buck Penrose to Bill Kennedy (Jan 11 1982) regarding the Jan 1982 SwRI emissions runs where the DeLorean engine passed NOx was 1.0. It goes on to further state that the prospects for meeting California standard of .7 for 1982 were excellent. From the same memo: HC .40 CO 2.2

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

From https://nepis.epa.gov/Exe/ZyPDF.cgi?Dockey=P100O9Z...

That NOx limit "1.0" sounds like the EPA limit which applied from 1981 (the era in which these engines came from) - the first line in that table. A number of production vehicles squeaked through those standards with no catalyst early on. Carburetors survived in some production cars until 1989 or thereabouts.

Tier 3 limits apply now: https://www.epa.gov/greenvehicles/light-duty-vehic...

There is now not a limit on NOx alone, or HC (now called "non-methane organic gases" NMOG) alone, but rather a total of the two, and the fleet average of the total of those two is 0.03 grams per mile. Just a wee bit tighter than what applied in 1981. Just a little.

This is not to take away from Smokey's work ... it's just that many of the things that he did, have now been addressed in other ways, and it's pretty unlikely that the no-exhaust-aftertreatment approach could have persisted.

The production spark-ignition gasoline engine in the Toyota Prius today is supposedly a smidge over 40% brake thermal efficiency at its best operating point, others are not far off, and that particular vehicle is designed to keep the engine operating as close as it can to its best-efficiency conditions as much of the time as it can.

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

(OP)
Just because you have a patent, doesn't mean it actually works. (I'm not saying Smokey's engine "didn't work" ... just saying, take what it says in a patent, with a grain of salt.)

Just because you have a patent, doesn't mean that patent contains ALL the information that you need in order to make the concept illustrated in the patent, work. (They never do.) Smokey was very good at keeping his mouth shut. A couple of pertinent quotes: , “Still, Smokey took much of the knowledge with him to the grave. As Smokey's daughter Trish Yunick puts it, "A patent application is a balance between disclosure versus secrets. You want to reveal just enough information to get the patent, but not so much that people can reverse-engineer your ideas. Smokey is gone, and some of the secrets went with him." Hot Rod Magazine. “It is really quite simple, and I am careful not saying too much. This is the only way I can be sure nobody knows how the system exactly works says Smokey” Swedish Hotrod Magazine

Now, let's scrutinise Smokey's patent linked to above, and compare it to "modern state of the art" - some of which involves engine features that hadn't been developed at that time.

"Background art."

The bit about fuel not getting completely vaporized, first I will point out that modern fuel injection is better at distributing that fuel, and secondly I will point out that engines that run on propane or natural gas don't have miraculously high efficiency compared to those running (properly) on liquid fuel. The patent was of his Phase I engines, He had plans for additional gains.

The bit about "carburetor double-pull" is a non-issue with port fuel injection, or direct-injection. The introduction of EFI was contemplated by Yunick and Knudson as early as 1980.

The patent is silent about how to control detonation, other than "hand-waving" and saying "it doesn't detonate". Flynn, Springer and Ingalls confirm

The patent is silent about how to get a normal spark plug to fire the supposedly lean air/fuel ratio, although the patent doesn't really get into that.

So, what do I really think is going on (at least to some extent)?

Smokey was a smart guy. He built lots of high-powered racing engines. He knew a thing or two about compression, and charge turbulence, and the like. I think there was some port-shaping trickery, and some squish-clearance trickery, and perhaps some clever combustion-chamber shaping, to achieve really fast-burn combustion. (Modern engines do this, too.) The advantage of his full-vaporisation strategy is that he didn't have to worry about charge turbulence "centrifuging" liquid fuel out of suspension. It's pretty likely that the spark plugs and/or ignition system contained a few secrets, too. Soliz is now doing forensics on the engines that he has. He has some insights to some of what you address but to get back to the issue, I am more concerned about the 81/82 runs at SwRI and those engines: AFAIK regular spark plugs and distributer.

And the other thing I suspect ... is cam timing trickery. Everyone has heard of the Atkinson cycle, or its forced-induction counterpart, the Miller cycle. Smokey's engine could have been an early implementation of the Miller cycle. Whether he did it by really early or really late intake valve closure, who knows ... I suspect the latter, as it's more compatible with valvetrain designs that were common at the time. Use late intake valve closure to cause the effective expansion ratio to be greater than the effective compression ratio ... use the turbo to compensate for the loss of volumetric efficiency when the driver asks for full load ... machine (otherwise) crazy compression into the pistons and head with really tight squish clearance to get good charge turbulence and a fast burn.

The modern V6 gasoline engine in my driveway achieves the Atkinson cycle upon command by fiddling with the intake and exhaust camshaft timing - the engine has variable valve timing with independent control of the intake and exhaust sides. That didn't exist (in production) in Smokey's era.

I would love to see an independent lab test out Smokey's engines to see what's really going on ... and perhaps a non-destructive look into the combustion chamber with a tiny camera through the spark plug hole to see what he's done with the pistons and the combustion chambers. Going down that road myself. That is why I am curious to know if a series of dyno pulls and reports by engineers of the caliber of Flynn and Springer would be enough to put the matter to rest. Soliz did a live YT where he opened up the Iron Duke that was most likely part of the abandoned partnership with Crane to make a kit version. I am not sure if it is archived, but there is a video about some of the cams that may have been used.

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

Smokey's patent discussing heating the fuel air charge sounds like a modest form of supercritical fuel injection.

P.S. Though transonic is out of business, the topic of supercritical fuel injection remains active
see https://www.technologyreview.com/2009/08/11/211065... for example




RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

(OP)
@BrianPeterson: Some insight into the thinking after the Jan 82 test from the summary report:

"With the current fuel and emission control systems installed on the
engine, it probably could not be made to pass the 1983 California standards.
If a three-way catalyst with feedback fuel control could be successfully
fitted to the engine, it should be possible to meet the 1983 California
emission standards."

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

In other words, the vaunted low emissions were not low enough to get rid of the cats, so there was no significant practical advantage there.

"50MPG, Zero Emissions, 1.8 HP/CI from a 1.3l Engine "

I was driving an 80 mpg car in 1984. Or at least that's what the press announced. It was actually 80 mpg at 30 mph on a flat road. It used a small 3 cylinder from Japan as the base of the engine. Its grandson became the Rover K series engine.

So 80 hp/litre. Certainly practical at the time, Lotus' 907 was 80 hp/litre (claimed, ahem) in 1976. Redline gets you there.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

Quote (RodRico)

Smokey's patent discussing heating the fuel air charge sounds like...
Heating the fuel air charge is a good idea, IF it occurs after TDC compression. Other than that, (liquid fuels only) you only want to add enough heat to make sure the fuel is adequately vaporized and sufficiently evenly mixed to enable more or less complete combustion of the available reactants. Additional heat before TDC compression beyond that amount will show up as reduced volumetric efficiency and/or reduced effective expansion ratio and hence reduced output, other factors being equal.
Now if there are other factors being manipulated to offset the VE/EER reduction, don't send me a link to a patent or startup website, elucidate the concept yourself if you understand it, otherwise, study up then come back and elucidate.

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

(OP)
@Greg: To be fair, that was 40 some odd years ago and carbureted. With current tech, who knows. As far as MPG is concerned, I have not been able to verify 50 or the 54 that I have seen in some places through actual tests or independent reports. What I can tell you is that I have seen the road tests that show 48.25. 133 Mile Loop of half city and half highway. 10 loops. Standard Drive-train "Slightly larger diameter, commonly available, tires were used in this test"

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

(OP)
@Lou

I freely admitted at the start of the thread that I am not an Automotive Engineer. Underwater Acoustics, E-Commerce, Automotive Retail Video are more along the lines of my expertise. I came here looking for answers, specifically as to whether contemporaneous Dyno readouts and reports from engineers would constitute proof that the engine worked as advertised. So, I will pose the question to you. If, if you had access to tests results, such as the read outs from dyno pulls, could read the associated summaries from the testers (whose fiduciary duties were not to Smokey) and they showed that the engine did work, would that be proof enough for you.

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

No. I have no access to the engine or the test stand or any other test set-ups.

If it was a miracle engine, there are many companies that would have done the same research and duplicated the technique. The patent expired in 2003, lack of fee payment, so there is no legal protection for using the ideas.

This tells me that companies that make engines have seen this, read the claims, and walked away. That rarely happens for fundamentally good ideas.

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

Why not just build another engine identical to Smokey's and test it? It looks like it would be a fairly simple build and it would be interesting.

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

(OP)
@BigClive: We are duel tracking. We are going to put the original 2.2 back in the 1981 Horizon and run it and modernize the Iron Duke and put it in an S10.

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

Quote (BigClive)

Why not just build another engine identical to Smokey's and test it? It looks like it would be a fairly simple build and it would be interesting.

The tricky bit is duplicating the aspects that aren't documented anywhere. Some (ignition timing calibration, carburetor calibration, etc) requires instrumented testing of a known sample engine. Some of it, e.g. cam profiles and timing, can be sussed out by making careful measurements of an assembled engine with only minor disassembly. Some of it, e.g. port shapes and combustion chamber shapes, can be established to some extent by careful inspection and may require more intense disassembly.

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

(OP)
We have five of them. Forensics are being performed on the test engine used for the failed kite version that was being contemplated with Crane. The problem with that one is that it is sort of a frankenstein version. For example the head had plenty of wear and the intakes valves showed the effects of high heat as would be expected, but the cylinders were brand new. The 2.2 that was in his daily driver is intact and has been run on the stand periodically over the years. The Chassis still has the dials as you can see in the picture and the half radiator that many believe to be mythical.

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

It's always good to have a thermodynamic theory explaining why it should work, as a road map for experimentation.

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

From the point of view of the 1970s and early 1980s, when it was the norm to have air and fuel kinda-sorta-roughly mixed together in a carburetor and then unevenly distributed to cylinders through a common manifold whose walls were soaked with liquid fuel that had dropped out of suspension ...

... I can see the point of using the "homogenizer", a.k.a. a draw-through turbo. I can see the point of heating the manifold walls - but not so much the mixture contained within! - in order to vaporise any liquid that drops out of suspension and lands on a manifold wall.

I have a gut feel that the heated intake manifold wasn't actually heating up the bulk air-fuel mixture as much as was claimed, especially when the engine is running under load (high mass-flow-rate through the manifold). Air isn't a particularly wonderful heat-transfer medium. The surface area of the inside of the intake manifold is nowhere near as much as, let's say, the surface area of the finned surfaces of a modern turbo intercooler, for example. You may heat up the intake manifold walls to (let's say) engine coolant temperature, but that doesn't mean the intake charge is going to be reaching that temperature, or even coming close to it.

Thinking about this some more. At idle, and at part-load (light-load cruising), you WANT the engine to "not make power". The normal way of causing it to "not make power", i.e. draw in less air and fuel, is to throttle it (and run it at high intake vacuum). The pistons try to pull their normal volume in anyhow ... pumping losses. But another way to "not make power" is to heat up the charge. Then you make the charge take up more space, and run at lower intake vacuum ... lower pumping losses. So in this way, perhaps the amount of surface area available to the charge, had a wee bit of careful thought and experimentation put into it ... enough so that with low mass flow rate through the manifold (part-load operation and idling, which account for most of the operating time of most automotive engines) the charge gets heated up significantly, but at high flow rate, the intake charge doesn't spend enough time in contact with the hot manifold walls to heat up all that much. Doing the experiments to find that balance ... is what Smokey Yunick did. I wouldn't put it past him.

Nowadays, the way you cause an engine to "not make power" at part load, is to play with the intake cam timing in such a way that the intake stroke is intentionally less effective. It either doesn't draw a full charge in (early intake valve closure) or draws it in but pushes some of it back out again (late intake valve closure). And you respond to the driver's request at the accelerator pedal, by changing the cam timing. I have two different examples of how this is achieved sitting in my very own driveway. One engine is a Chrysler V6 Pentastar, which has variable valve timing that is separately adjustable on the intake and exhaust camshafts. The other one is a Fiat 1.4 MultiAir, which operates the intake valves hydraulically through a little solenoid valve that intentionally makes the cam lobe use less of its stroke at part load.

It would not surprise me one bit, to find out that Smokey's engines used conventional camshafts (single camshafts for all valves were standard practice back then) but with all event timings shifted later - achieving late intake valve closure, and simultaneously allowing the power stroke to be lengthened. The resulting impaired volumetric efficiency, he made up for with the turbocharger.

Nowadays, the way you avoid fuel maldistribution is to have a separate injector for each cylinder ... and as often as not nowadays, injecting directly into the cylinder.

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

I have a couple of engines in my fleet that were part of an emissions upgrade program. They're 2-stroke uniflow 71 series Detroit Diesel engines. The concept was to grind much of the lift off the exhaust cams and retard injection timing which simulated EGR and reduced NOx and PM emissions. A turbocharger was added to compensate for the loss of power. It's a good system and met US EPA Tier 2, Clean Cams Technology Systems was the outfit but it seems the company is defunct so we'll be replacing those engines this year as they've reached their 24k hour overhaul interval (with zero breakdowns).

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

(OP)
@GregLoCock, I am sure we will at some point. Currently our Dyno is a CASREP victim of the thousand year winter event we had a few weeks back. Meanwhile, What's wrong with this for MPG:

"A mileage test for the vehicle was conducted using a 133 mile driving loop that included both city and highway speeds. The vehicle drive train, i.e., transmission, differential gearing, etc. was standard and unmodified. Slightly larger diameter, commonly available, tires were used in the test. With a final drive ratio of 2.3-1, the engine R.P.M. at 55 M.P.H. is 2,000. The vehicle speed was maintained within 2 mph of the posted speed limit. One hour and forty minutes of the test was spent in city traffic and an equal amount of time was spent in highway traffic. The 133 mile test loop was repeated 10 times and at the conclusion of the test it was found that the vehicle averaged 48.25 miles per gallon. The disclosed performance gains in both fuel economy and power output were obtained without sacrificing driveability.
It was also found that the engine was not prone to detonation even under high engine loads and low engine rpm. Moreover, the vehicle could be smoothly accelerated in high gear, from a road speed of 20 MPH, under both part and full throttle, without evidence of engine hesitation or flutter. The constant downshifting to maintain sufficient engine RPM often required with conventional, small displacement engines was found to be unnecessary."?

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

What's missing is the comparison to what the conventional engine would do under the same circumstances in the otherwise-same vehicle. (What vehicle was it?)

48 mpg US = around 5 litres per 100 km. That's pretty good, but not completely out of bounds for what many small cars of that era (and even now, if you can find one) will do with a normal engine under the hood if the driver has a light foot. Quote - "vehicle speed was maintained within 2 mph of the posted speed limit" - main reason my modern little car uses (somewhat) more than that, is that I don't drive like that!

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

(OP)


An engine and fuel system embodying the present invention was constructed and installed in a 1980 Buick Skylark. The vehicle weighed 3,005 lbs, two passengers, full fuel accelerated 0-060 M.P.H. in 9.4 seconds. The mechanical parameters for the engine are listed in Table I. A measured torque curve is illustrated in FIG. 10 and indicates a remarkably level torque output, in excess of 225 ft-lbs, for an operating range of 2000-4400 rpm. Those in the art will recognize that the disclosed power output for a three-cylinder engine having a displacement of 125 cubic inches and weighing only 320 lbs. in its operating mode including clutch and bell housing is substantially more than one would expect from an engine this size. Moreover, it was found that the engine was remarkably vibration free and the radiator with which the above identified vehicle was originally equipped was reduced in size and capacity by about 50%.
TABLE I
Engine Type:3 cyl,overhead valve
Displacement: 125 cu.in.
Bore:3.950 in.
Stroke:3.4 in.
Rod length6.5 in.
Horsepower 240 Hp at 4000 RPM (special high performance fuel-test code 20 with 21 pound boost)
Horsepower 190 Hp at 4400 RPM (93 octane unleaded gasoline with 10 pound boost)
Weight 320 lbs.
Fuel economy 48.25 MPG (combined city and highway)

https://www.aboutautomobile.com/Fuel-Economy/1980/...

https://www.conceptcarz.com/s16336/buick-skylark.a...

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

I have to convert those numbers to metric to make sense of them, but having done so ...

The torque curve above coincides with the claim of 190 hp at 4400 rpm, so from that, take the boost pressure to be 10 psi (0.7 bar gauge pressure, 1.7 bar absolute).

The BMEP based upon the claimed torque and RPM is around 19.3 bar.

For a forced-induction engine, at first approximation, divide this BMEP by the ratio of absolute pressure to atmospheric pressure (1.0 bar) to establish an estimate of what the BMEP would be in naturally aspirated form. It's 11.4 bar. This makes an implicit assumption of perfect intercooling.

By purposes of comparison, a run-of-the-mill low performance 2 valve per cylinder production car engine is commonly 11 - 12 bar BMEP, a good production engine 13-ish, and the very best naturally-aspirated 4 stroke spark ignition racing engines that are running on gasoline (no exotic fuel chemistry) - we are talking Formula 1 or NASCAR here - are in the 15 bar range.

So, it's fair to say that whatever cam timing or intake-heating trickery was applied, was probably costing it about 10% - 15% in specific torque. That would coincide with an increase in absolute temperature of 10% - 15%, which is not far off the deficit that one would expect with that boost pressure by not using an intercooler.

One other small thing worthy of mention here. Provided that you can keep the contained volume of the intake manifold down (and there's no intercooler, so that's easier in this case), draw-through turbo designs have the advantage that they can keep the turbo compressor spinning faster under part-load conditions because the compressor is operating under vacuum (so there's less load on it) ... it doesn't have to wait as long to spin up when the driver opens the throttle.

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

(OP)
The mythical half radiator. The original 2.2 and the Horizon it came out of:


RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

(OP)
@Brian Petterson. Spot on on some of your conjecture.

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

Keep it coming. I would love to get a closer look at the intake manifold (on any of them).

My working theory is that the surface temperature of the intake manifold may have been in the claimed temperature range, but the temperature of the intake charge was nowhere close to that at full load, although closer to it at idle and light load.

The timing of the valve events is another thing of interest.

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

(OP)
We thought we had another clue with regard to the intake manifold, tuned out to be a false lead.

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

Thanks for letting us know.

je suis charlie

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

(OP)
Quick update. I was able to track down one of the original engineers that tested the engine in 81/82. Had a great conversation. Meeting with him Saturday. I will keep y'all posted. Still looking at having the car run on the 9th of May.

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

(OP)
We will not make the run of the Horizon this weekend, but I will be posting some of the Dyno pulls on Sunday. We do, now, have all three tests results, Mar 81, APR 81 and Jan 82. so, we can track progress. Meanwhile, here are some pictures from the testing done in 82 and the DMC on the Dyno.

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

(OP)

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

(OP)

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

It may be that Smokey correctly anticipated the current downsized, turbocharged trend for gasoline passenger car engines, but I don't see anything remarkable in those results.
It could be that by time they were able to meet emissions with a validated deterioration factor (this typically involves sacrificing some power and efficiency), assuming they got that far, there wasn't enough advantage left to justify further development at that time.

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

RE: Another Henry Smokey Yunick Hot Vapor Engine Thread

If they were discussing when to change gears, I smell shenanigans. When performing the EPA test procedure, thou shalt upshift to 2nd gear at 15 miles per hour. Thou shalt upshift to 3rd at 25 mph, and 4th at 40 mph. The end. All cars are treated the same. The absence of being able to factor in engine load is a lot of why modern automatics do better than manuals (that wasn't true in Smokey's era, in which three speec automatics were the norm and lock-up torque converters with simplistic control logic were a new invention).

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