Revolutionary High-Efficiency Engine-Too Good to be True?

TDIMeister

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VCs will probably pass me by because I don't claim impossibilities. I'm also not skilled at making websites with snazzy animations that make my inventions to be more than they are. A running joke in the engine/energy industry is that the amount of VC funding is in direct proportion to the fanciness of websites, overblowing of claims (it's fine to truly have a disruptive technology and a step advance to the state-of-the-art) and prominence of the "Investors" link of the website. :D I tend to subscribe to the principle of "under-promise, over-deliver." Which are not two traits VCs take kindly to.
 

manual_tranny

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Am I correct in saying that it would benefit economy to create a crank that would allow variable compression and variable time at TDC? I think I might have a design that could make this happen. Unfortunately, no matter how much I try, I stink at drawing and my CAD classes won't start until July. When I finish the drawings, (hopefully a couple days) I'll PM some of you guys so you can let me know if it's worth persuing this idea. To me, it looks too good to be true... but I lack the ability to properly criticize my design at this point.

If I had something with potential, would you all have some advice on how/where to start a patent process, and/or specific engineer-aquainted patent lawyers to contact? I'm not trying to put the cart before the horse, but I understand it takes a patent lawyer to check and see if you actually have a new design or if you've just re-made the wheel....
 

manolis8

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Am I correct in saying that it would benefit economy to create a crank that would allow variable compression and variable time at TDC? I think I might have a design that could make this happen. Unfortunately, no matter how much I try, I stink at drawing and my CAD classes won't start until July. When I finish the drawings, (hopefully a couple days) I'll PM some of you guys so you can let me know if it's worth persuing this idea. To me, it looks too good to be true... but I lack the ability to properly criticize my design at this point.

If I had something with potential, would you all have some advice on how/where to start a patent process, and/or specific engineer-aquainted patent lawyers to contact? I'm not trying to put the cart before the horse, but I understand it takes a patent lawyer to check and see if you actually have a new design or if you've just re-made the wheel....
If you want to patent your design, keep it secret until the patent application.

You don't need to put CAD drawing in your patent application. Even big companies use hand made, poor quality, yet explanatory drawings of what they claim.

To apply for a patent in the USA patent office (US-PTO) is relatively easy and cheap:

The patent application costs US462$ (for small entities), needs not a patent attorney, is for all people of the world (not only the Americans) and can be done on-line: You prepare a pdf file for the Description-Claims-Abstract, another PDF file for the Drawings, and a PDF file for the "Oath or Declaration", all in English. You can pay on-line by credit card.

After the application for a patent, your idea is patent pending; then it is relatively safe to show it to anybody.

If a patent is finally granted by the USPTO, there is an additonal US1055$ cost (issue fee and publication fee). I.e. the total cost for taking a patent in the US (the biggest market of the world) is about US1500$ if everything is OK.

No more than 12 months after the initial application you can proceed to other patent offices (or to the PCT / WIPO) with the inital US-PTO application as the priority document, but now the cost is high. Otherwise you lose your intellectual property in the rest markets of the world (i.e. outside USA).

This is an unconventional application of the OPRE engine:



and this



is from the video at http://www.pattakon.com/fly1/OPRE_fly1.MOV of the propulsion unit running on Diesel fuel.

Think the effect of this design on the weight and durability of the frame of a small airplane.
Also on the maximum total range and on the fuel cost.
The propulsion unit is: direct injection Diesel, lightweight, vibration free, with zero total momentum of inertia.
Think the zero effect of a sudden change of the load (closed to WOT) or of a missfiring on the small airplane stability.
Think also how easily the airplane can change direction.

Thanks
Manolis Pattakos
 

TDIMeister

Phd of TDIClub Enthusiast, Moderator at Large
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Placing the propellers like that will require some creative mounting and make the engine a stressed member because of the yawing moment that the offset, counter-rotating propellers cause. Also, I am no expert but I suspect that the interference of airflow of the partially- and assymmetrically overlapping propellers would be problematic as well.
 

manolis8

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Placing the propellers like that will require some creative mounting and make the engine a stressed member because of the yawing moment that the offset, counter-rotating propellers cause. Also, I am no expert but I suspect that the interference of airflow of the partially- and assymmetrically overlapping propellers would be problematic as well.
The mounting of the propellers is quite simple.
The mounting of the engine is simpler.
The combustion force on each piston is more than 5 tons; i.e. middle engine is an overstressed member.
The point is to release the rest structure (the casing of the airplane, for instance) from vibrations and loads.
In practice, I see no reaction changing the direction of the OPRE with two heavy counter-rotating flywheels (or with two counter-rotating rotors).
The cylindrical block of the engine interconnects the bearings of the two crankshafts and provides the necessary strength.

Because I can’t see an issue, please be more specific about the problem you see.

To put it differently:

If you remove the lower rotor from the lower crankshaft and secure it on the upper crankshaft (i.e. both rotors rotate at the same direction), during operation it is quite difficult to rotate the engine about its cylinder axis. The higher the revs, the more difficult and slow the rotation. The engine is a stressed member. And its stressing is from its mountings to the crankshaft bearings.

If you try the same having one rotor on each crankshaft (now the rotors are counter-rotating), during operation you can rotate the engine about its cylinder axis without resistance. In this case, only the part of the engine between the two crankshafts is a stressed member.


For the interference of the rotors:
the helicopters with the intermeshing rotors (synchropter) and the airplanes with contra-rotating propellers were quite efficient solutions. The contra-rotating propellers are too noisy. The offset of the two rotors reduces the noise.

Thanks
Manolis Pattakos
 

GoFaster

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Am I correct in saying that it would benefit economy to create a crank that would allow variable compression and variable time at TDC?
It depends on the situation and there are trade-offs involved.

Three situations need separate discussion - traditional spark ignition SI (detonation limited), traditional compression ignition CI (fuel/air mixing limited), proposed "premixed Homogeneous Charge Compression Ignition" HCCI (reliability of ignition limited). I'll use VCR as an abbreviation for Variable Compression Ratio to save a bunch of typing.

A situation common to both SI and CI is that the combustion process depends on turbulence. It's more critical with CI where turbulence also has to mix fuel and air. But even with a SI engine, "squish" turbulence near the end of compression speeds up combustion a fair bit. A fast-burn engine with decent squish-bands (but not too much) will usually be more efficient and run better than one with an open low-turbulence chamber. How do you get squish ... by having the piston closely approach the head. But with VCR you want high compression in the situations where detonation is least prominent (low load) and this is your limiting factor for how close the piston can get to the head. At high load where detonation is more likely, you have the piston stopping further down the cylinder - reducing squish turbulence at the time when you need it the most. Not favorable ...

With CI it's even more critical; look at the shape of a TDI piston and how closely the part outside the bowl comes to the head and valves. If you stop the piston further down the bore then it destroys fuel/air mixing. Definitely not favorable.

Maybe there is another way of doing VCR without having the piston-to-head geometry change but I don't know of a way to do it that doesn't have other, bad, horrible-combustion-chamber-shape implications.

HCCI is another matter because it's not relying as much on squish turbulence to speed combustion or mixing. It doesn't need a turbulent chamber late in the compression stroke (only during intake stroke and whatever turbulence remains afterward, to complete air/fuel mixing). In this case, VCR could very well be the key for getting HCCI to operate successfully over a wide-enough range of speed and load and temperature.

I have a feeling that soon-to-come variations on gasoline direct injection are likely to wipe out whatever hypothetical benefit remains of VCR on spark-ignition engines. Mazda Sky-G will have 14:1 compression ratio - and its combustion chamber shape is almost diesel-like and very reliant on the piston very closely approaching the head, just like with a diesel. Beyond that compression ratio, there are diminishing returns and you start losing more due to heat losses anyway. Don't need VCR if you can run the high (optimum) CR all the time, even at full load!

Now, as for the "time near TDC" ... this is a lot more murky. With a normal engine, it's affected by the rod-to-stroke ratio. The "time near TDC" is always shorter than the "time near BDC". Manolis8 has a nifty design with the con-rod reversed which reverses this. So the question is whether you want more time near TDC or not. From all I can gather, this is somewhere in between an "it depends" and an "it doesn't matter".

If you have a combustion process that is "slow" or "ignition lag limited" etc., then having more time near TDC will give more time to get it done at a phase in the cycle where more work can be extracted. This favors longer rods or Manolis' reversed-rod arrangement. Diesel and HCCI come to mind here. BUT.

- The longer the hot gases sit around near TDC, the more heat they lose to the piston, cylinder liner, etc. So from this point of view, you need to spend the time near TDC that you need to spend, but once the combustion gets well established, you need to get the gases expanded pronto before they lose too much heat!

- If it is a premixed detonation-limited situation (SI engine) you don't necessarily WANT the piston to hang around near TDC too long. You need to get the expansion going so that the end gas is less likely to detonate. Formula 1 car engines - which are gasoline fueled - use this approach. Compression ratio is high, but after ignition, the expansion occurs so quickly that the end gas doesn't detonate. Apparently, beyond 12,000 rpm, detonation is almost impossible to occur. Those engines are not designed to have high volumetric efficiency at low revs - probably intentionally; this acts like a lower compression ratio. Note how high the idle speed is on those ...

With a SI engine, a fast-burn chamber and NOT spending more time near TDC seems more like the way to go. Get the ignition going (multiple spark sources, if needed), get the mixture burned pronto before it has a chance to detonate, and get it expanded before it pumps too much heat into the pistons and valves (and loses some of its ability to do mechanical work). The Mazda Sky-G engine has a very compact, confined, almost diesel-like chamber in the piston and they're using direct injection, which is probably/hopefully putting the fuel in the center of the chamber and away from the end gas. If there's no fuel in the end gas, it can't detonate.

Other random effects

- If you are spending more time near TDC then you're spending less time near BDC, which means less time for cylinder filling at high revs.

- Short rods (the implication of which is more time near BDC and less near TDC) introduce more secondary imbalance into the engine. Depending on the layout and number of cylinders, this may or may not be an issue. 4-stroke even-firing inline-4 ... big issue.

- Long rods need to be thicker and heavier to resist failure in buckling. That adds weight. If you want to spin the engine fast, that extra weight is not good. If you want to run diesel-like compression ratios (and a fast-burn chamber that raises cylinder pressures), buckling is a consideration. (Manolis' reversed-rod engine has them in tension ...)

- Of course, the effect on the overall height of the engine has to be considered. Long rods means taller deck height.

Smokey Yunick was always a fan of long rods. Nowadays ... in the hot-rodding world, there's no clear pattern. In the high revving motorcycle engines and Formula 1 cars, the rod/stroke is usually in the 2:1 range give or take. VW engines have short rods, which helps with buckling stress in the diesels ... even if the real reason is that VW is saddled with their 88mm bore spacing and they are stuck with long-stroke designs as a result, but they still want to not make the engine too tall, so short rods it is, rightly or wrongly.
 

manual_tranny

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My goodness, thank you for all that! I will read through it a few times to make sure I retain it!

The design I have in mind might be better suited to generate electricity at a constant, slow speed. I would like to think that my design might work for efficiency over output. Like a Lister, but hopefully with less weight and size. I'll throw some drawings at the patent office and post them up here when I can.
 

manolis8

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Some issues of the Pinnacle engine:
the sealing, the lubrication and the wear of the sleeve valves;
the cooling of the cylinder;
the lubricant control (the same problem with the two stroke port engines).

The question is:
does the Pinnacle combine the advantages of the four-stroke engines with the advantages of the two-stroke opposed-piston engines,
or does it combine their disadvantages?

The PatFour engine :



at the bottom of http://www.pattakon.com/pattakonPatPOC.htm is a four-stroke opposed-piston single-crankshaft engine having conventional poppet valves.

Do you see any advantage of the Pinnacle engine over the PatFour?
 

TDIMeister

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The advantage is that Pinnacle is receiving millions of USD. Are you? ;) I hope you see the sarcasm.
 

Ski in NC

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Two types of engine development businesses out there: 1) Companies trying to build a commercially successful and better engine, and 2) Companies trying to suck up government R&D dollars with doomed designs but super fluff and gloss.

We see plenty of #2. Where are the engines??? Rednecks can make all kinds of crazy things run for under $10k. And the millions these firms have spent and no converted Tacoma's driving around with the super new engines????

#1 companies are quietly doing their job....We'll hear from them when their product is ready.
 

eddif

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It depends on the situation and there are trade-offs involved.

Three situations need separate discussion - traditional spark ignition SI (detonation limited), traditional compression ignition CI (fuel/air mixing limited), proposed "premixed Homogeneous Charge Compression Ignition" HCCI (reliability of ignition limited). I'll use VCR as an abbreviation for Variable Compression Ratio to save a bunch of typing.

A situation common to both SI and CI is that the combustion process depends on turbulence. It's more critical with CI where turbulence also has to mix fuel and air. But even with a SI engine, "squish" turbulence near the end of compression speeds up combustion a fair bit. A fast-burn engine with decent squish-bands (but not too much) will usually be more efficient and run better than one with an open low-turbulence chamber. How do you get squish ... by having the piston closely approach the head. But with VCR you want high compression in the situations where detonation is least prominent (low load) and this is your limiting factor for how close the piston can get to the head. At high load where detonation is more likely, you have the piston stopping further down the cylinder - reducing squish turbulence at the time when you need it the most. Not favorable ...

With CI it's even more critical; look at the shape of a TDI piston and how closely the part outside the bowl comes to the head and valves. If you stop the piston further down the bore then it destroys fuel/air mixing. Definitely not favorable.

Maybe there is another way of doing VCR without having the piston-to-head geometry change but I don't know of a way to do it that doesn't have other, bad, horrible-combustion-chamber-shape implications.

HCCI is another matter because it's not relying as much on squish turbulence to speed combustion or mixing. It doesn't need a turbulent chamber late in the compression stroke (only during intake stroke and whatever turbulence remains afterward, to complete air/fuel mixing). In this case, VCR could very well be the key for getting HCCI to operate successfully over a wide-enough range of speed and load and temperature.

I have a feeling that soon-to-come variations on gasoline direct injection are likely to wipe out whatever hypothetical benefit remains of VCR on spark-ignition engines. Mazda Sky-G will have 14:1 compression ratio - and its combustion chamber shape is almost diesel-like and very reliant on the piston very closely approaching the head, just like with a diesel. Beyond that compression ratio, there are diminishing returns and you start losing more due to heat losses anyway. Don't need VCR if you can run the high (optimum) CR all the time, even at full load!

Now, as for the "time near TDC" ... this is a lot more murky. With a normal engine, it's affected by the rod-to-stroke ratio. The "time near TDC" is always shorter than the "time near BDC". Manolis8 has a nifty design with the con-rod reversed which reverses this. So the question is whether you want more time near TDC or not. From all I can gather, this is somewhere in between an "it depends" and an "it doesn't matter".

If you have a combustion process that is "slow" or "ignition lag limited" etc., then having more time near TDC will give more time to get it done at a phase in the cycle where more work can be extracted. This favors longer rods or Manolis' reversed-rod arrangement. Diesel and HCCI come to mind here. BUT.

- The longer the hot gases sit around near TDC, the more heat they lose to the piston, cylinder liner, etc. So from this point of view, you need to spend the time near TDC that you need to spend, but once the combustion gets well established, you need to get the gases expanded pronto before they lose too much heat!

- If it is a premixed detonation-limited situation (SI engine) you don't necessarily WANT the piston to hang around near TDC too long. You need to get the expansion going so that the end gas is less likely to detonate. Formula 1 car engines - which are gasoline fueled - use this approach. Compression ratio is high, but after ignition, the expansion occurs so quickly that the end gas doesn't detonate. Apparently, beyond 12,000 rpm, detonation is almost impossible to occur. Those engines are not designed to have high volumetric efficiency at low revs - probably intentionally; this acts like a lower compression ratio. Note how high the idle speed is on those ...

With a SI engine, a fast-burn chamber and NOT spending more time near TDC seems more like the way to go. Get the ignition going (multiple spark sources, if needed), get the mixture burned pronto before it has a chance to detonate, and get it expanded before it pumps too much heat into the pistons and valves (and loses some of its ability to do mechanical work). The Mazda Sky-G engine has a very compact, confined, almost diesel-like chamber in the piston and they're using direct injection, which is probably/hopefully putting the fuel in the center of the chamber and away from the end gas. If there's no fuel in the end gas, it can't detonate.

Other random effects

- If you are spending more time near TDC then you're spending less time near BDC, which means less time for cylinder filling at high revs.

- Short rods (the implication of which is more time near BDC and less near TDC) introduce more secondary imbalance into the engine. Depending on the layout and number of cylinders, this may or may not be an issue. 4-stroke even-firing inline-4 ... big issue.

- Long rods need to be thicker and heavier to resist failure in buckling. That adds weight. If you want to spin the engine fast, that extra weight is not good. If you want to run diesel-like compression ratios (and a fast-burn chamber that raises cylinder pressures), buckling is a consideration. (Manolis' reversed-rod engine has them in tension ...)

- Of course, the effect on the overall height of the engine has to be considered. Long rods means taller deck height.

Smokey Yunick was always a fan of long rods. Nowadays ... in the hot-rodding world, there's no clear pattern. In the high revving motorcycle engines and Formula 1 cars, the rod/stroke is usually in the 2:1 range give or take. VW engines have short rods, which helps with buckling stress in the diesels ... even if the real reason is that VW is saddled with their 88mm bore spacing and they are stuck with long-stroke designs as a result, but they still want to not make the engine too tall, so short rods it is, rightly or wrongly.
While I will probably never put in the effort to understand all this I will make a comment on the problem with the Squish, Turbulence and possibly
Buckling (?).

http://www.somender-singh.com/
Somender Singh has recently posted something I find most interesting. If you read through his sex post you find out that one of the things that happens in the use of grooves: The grooves allow close squish bands for turbulence but allow the gasses right next to the cylinder bore to escape before they oppose the movement of the piston right as it approaches the head. This is my wording but helps me understand what his grove theory is all about. The removal of the trapped high pressure allows the hydrocarbons to stay suspended as a fog rather than be compressed enough to become liquid again (Another eddif redneck wording and theory as to why the Singh grooves work). So allowing minimum clearance and getting turbulence is possible IMHO.

eddif
 

GoFaster

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I know about those grooves. For those to work, the piston MUST closely approach the cylinder head. If the piston does not closely approach the head then neither those nor more traditional turbulence-generation squish bands do NOT work. All VCR mechanisms that I have seen, go into "low compression" mode by making the piston NOT approach the head (it stays further down the cylinder).

If the piston doesn't approach the head closely then squish bands don't work, and Singh grooves or PowerLynz or whatever else you want to call them don't work. If the piston doesn't closely approach the head, then the chamber stays "quiet" - low turbulence - slow combustion - detonation - you name it.
 

DrSmile

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Epitaph to this thread.... as I prognosticated, not only did this never go anywhere (except pull money out of rich men's pockets) in 12 years but the Ecomotors website seems to now be unofficially dead. It joins the ranks of the algae diesel company Solazyme, the Zeroshift transmission, and the Revetec controlled combustion engine.
 
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Willy den CGI

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Sweden
You have to wait a second before you declare the OPOC-engine as dead. Achates Power will most likely show several engines at this years end and at least one OEMs is reported to tool up for volume production.

http://www.motortrend.com/news/at-least-one-automaker-plans-to-produce-an-opposed-piston-engine/

and

SAE

http://www.nxtbook.com/nxtbooks/sae/17AUTP02/index.php#/18

The advantage Achates engine has is the ability to mount them in current trucks. EcoMotors had to design a completely new flat engineroom
 
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