Instructables

Can Non-Hybrid Cars Get 100+ MPG Today?

 

We're not talking about hybrids here; our topic is cars powered by the basic IC-engine that relies on gasoline and not electric motors. Today's gasoline engines are not designed to combust/burn gasoline efficiently. Even with the advent of using high pressure fuel injection techniques that are computer controlled, we still fall short of the mark. Partly because liquid gasoline can't burn, only gasoline vapors burn, and there lies our problem. The same goes for injecting the high pressure droplets of fine-mist liquid gasoline that enters the engine cylinder using our current nozzle ejector technology, it doesn't all burn at the same time!

Engine designers assume that these droplets are instantly vaporized by the engine's hot cylinder walls, and then instantly explode/combust when ignited by the sparkplug. Not true, up to 2/3 of the fuel isn't vaporized and doesn't combust until later on in the cycle. The 1/3 that gets almost-instantly vaporized and burns will do so within the several thousandths of a second (Fig-1) it has before the piston moves down its 1/2-stroke (out of today's 4-stroke cycle) completing the engine power-portion of its cycle. This releases power and tremendous heat which indeed vaporizes the remaining ~2/3 of our fuel from its liquid droplet form, but too late. It essentially does so when the power stroke is almost over or the piston is just about ready to move into its up-stroke (2nd stroke of our four stroke cycle) phase. So, because of poor vapo-timing we have 2/3 of our fuel virtually wasted by exploding at near the bottom of the power stroke.

This incorrect explosive timing, which happens to most of our fuel, imparts very little energy into the crankshaft because its effective "moment" (a product of explosive force and radial-component distance from crankshaft center) is insignificant by then. Various attempts at adjusting the combustion timing spark hasn't made a significant difference. Even though ~2/3 of the fuel is now exploding and providing a huge force, its small "influence" arm distance is rapidly diminishing to zero, and any huge downward force times near zero arm-length is still zero.

Some clarification here, technically thermal-efficiency is not improved, pretty much all of the gasoline gets combusted today. That means the energy of the fuel is almost totally released, but not effectively used. The problem is the timing it takes to convert fuel-injected gasoline droplets into vapor to combust at the correct engine rotational time and extract that expended energy. If you did the math for any size engine rotating at say 3200 RPM, you would find that a 4-stroke engine can only extract that energy from combustion during one of the four strokes. And the time it takes to make that stroke happen is only about 9.4 thousandths of a second or 9.4 milisecs (msecs).

Now picture the piston just below TDC, all its valves closed, under pressure and containing all the fuel and air it needs to combust. At this point our deadly cocktail has about half of the 9.4 or about 5 msecs to complete combust after the timed sparkplug ignites it. The half factor exists because the max portion of our power stroke (moment arm) occurs at the mid-stroke of the piston sliding down and turning the crankshaft. If all of our fuel isn't combusted by then, the moment-arm or distance from the piston-center to the crankshaft quickly reduces to zero. Again, only vapors combust within a healthy 2 msecs (Fig-1), while fuel droplets take a relatively long time (>5 msecs) to vaporize before it can combust. Unfortunately nature is stubborn and vaporizes ~2/3 of our injected fuel droplets only during roughly the second half of the power stroke. So this huge amount of energy gets wasted because even though the forces of combustion are huge, its moment arm is rapidly approaching zero. Infinity times zero is still zero!

Engine designers/engineers have been plagued by this phenomenon ever since the creation of the 4-stroke gasoline or Otto cycle engine. We need to improve this intermittent combustion/explosion process by combusting all of our injected fuel at the correct timing sequence. This is accomplished by injecting only vaporous fuel which will produce ~3X the power we now get. Another way to state this is, for the same power that we now get from a gasoline engine, if we burned the fuel correctly, we would only need 1/3 the fuel consumption to get 3X the current MPG.


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RT-101 (author) 1 year ago

Great questions about my theoretical holes! First, sorry for my delay as I’ve been busy on other tech things. Here are your answers:

1)      Education be damned! You strike me as a good thinker and perhaps tinkerer, and that’s all that counts.

2)      Advance timing doesn’t really properly address the issue of absolute engine power generation.

3)      Keeping a Gasoline Vapor:  Let’s assume our gasoline mixture has the average molecular composition of C10H22 (molecular weight of 142 kg/kmol) which yields a stoichiometric fuel/air ratio of 0.0673 or your definition of 15:1 air-to-fuel ratio. Thermodynamic tables of vapor pressure (by extensive testing of different gasoline mixtures) states that at an ambient (engine cylinder) pressure of 2 atmospheres (30 psia or 2.026E+05 Pa) we need a temperature of ~310 F to keep the gas a vapor. Now at typical gasoline engine compression ratios of 6:1 or 6-atm or ~90 psia we must keep the vapor at or slightly above ~500 F to keep it a vapor or it will compress back to a liquid.

4)      Auto Ignition & Controlled Detonation:  So I inject my vapor at a temperature of 500+ F into the cylinder and it stays a vapor. Now auto ignition occurs at around ~495 F, but that assumes I have enough air (oxygen) handy to ignite the fuel vapor, namely from at least 10 up to 50 times the amount of fuel vapor mass. We’ll play some thermodynamic games here and make sure that the combo of incoming air temperature plus gasoline vapor temp yields the right temperature mixture of just under ~495F so we don’t explode! Even if we go another 10 to 15 F lower than this to absolutely preclude detonation, so what! The few miliseconds (ms) we have, due to RPM piston-motion compression before controlled detonation,  can’t re-condense more than maybe 5% or so of our vapor, so we combust 95% at our controlled timing for a max power stroke. Compare this to today’s ~15 – 25% combustion of available fuel droplets for power and we’re ahead by a factor of at least 3X if not 6X !   Totally mind blowing!

5)      Cold Starts:  We’re talking about warm, steady-state engines here. I can’t give you everything! Yes, initially our cold engine won’t be too much better than today’s ratty engines. So how long does it take to warm up your engine?

6)      NOx Emissions:   NOX or nitric-oxides are oxides of nitrogen typically NO and NO2 compounds. These compounds mix with water vapor (H2O) in the atmosphere to form nitric acid (HNO3) or acid rain which is bad. NOX only forms at very high temperatures like that of our vapor-combustion engines. So how do we stop it? The chemistry of how NOX forms is not totally understood during its intermediate stages where it first forms NO then NO2. Wikipedia is getting much more reliable and now properly states that the formation chemistry takes up to 10 seconds to form a 50% NO2 concentration or 10,000 ppm from an initial formation of 20,000 ppm of NO concentration (lower ppm’s imply longer formation times). Taking this further, we can expect our NO formations to also take some minimal period of time beyond just forming instantly. Let’s assume that since it forms first, it therefore forms more rapidly than NO2 by a factor of at least 100 or instead of 10 seconds it takes 0.1 seconds or 100 ms. Even if it’s faster again by another say factor of 10 times (making it a total of 1000 times faster), that’s still 10 ms needed to form its chemistry. Any four stroke IC-engine running at 2500 RPM only has 12 ms for its power stroke to end. Within that total piston stroke time period, the above calculates a detonation time of ~2 ms required for complete combustion. Then the gas expands to create the remaining power stroke with ~10 ms left. We therefore form only about 2/12 or 17% of today’s NOX emissions. Our engine detonates 100% within only 2 ms while today’s engine keeps burning and forming NOX over the entire 12 ms stroke. Actually we generate even lower pollution since today’s cars continue to burn even while exhausting its combustion products into the manifold. So it can easily burn for another 12 ms, making our ratio for NOX production as low as 2/24 or only 8% of today’s cars.     

I have been very interested in experimenting with increasing fuel efficiency in ICE vehicles. I will start out by saying I am a Layman. I am not educated in thermodynamics. I work as a Diesel technician. I understand ICE power plants. I see only small holes in your theses. Timing, good starting point. advance timing will produce more HP. It comes with a cost (heat). Phase change of fuel, How do you plan to over come the pressure in the cylinder and prevent phase change from pressurization of the vapor? Higher compression ratio? Now we need to run gasoline engines with detonation ignition. This creates other problems. Cold start conditions. What do we do for that? One last thing.Would NOx. be higher?
Kiteman1 year ago
[citation needed]
RT-101 (author)  Kiteman1 year ago
While citations and references are always important when you publish technical designs as I have in the past, with the advent of the Internet and resources like Wikipedia, etc., sources are becoming as ubiquitous as the air we breath. Anyway, Instructables and Forums don’t require credentials do they? Although I definitely would provide DARPA with appropriate references and theoretical analyses should they be interested in contacting me. However, I've worked for them in the past and I won’t move to contact them over this concept!

Kiteman RT-1011 year ago
When you are making *any* technical or scientific, reliable data is an absolute requirement, even if it's just a link to the peer-reviewed research upon which you base your claims.

You make several assertions about the assumptions of engine designers, yet an actual engineer is contradicting you, and you seem to think you are being complimented!
  • "Extraordinary claims require extraordinary evidence"
  • "Onus probandi incumbit ei qui dicit, non ei qui negat"
  • "That which is asserted without evidence can be dismissed without evidence."
Ergo, I dismiss your claims.
RT-101 (author)  Kiteman1 year ago
I respect your feedback and feel compelled to respond.
Not wanting to be dismissed summarily, I’ll take you up on your challenge of evidential inferences. However, I’m a believer that too many references just lead to confusion, and in the end, one just has to make up their own mind as to feasibility. I’m also currently preoccupied with other things and can’t create a prototype of the engine concept discussed here, however, I’ve completely analyzed and designed a technically workable concept.

Out of respect for your feedback, which I’m trying to solicit through these blogs, here is historical evidence to make folks think. I've culled only those technological achievements where prototype hardware was built and shown to dramatically improve IC-engine performance while also back dating my evidence to the start of the 20th century:

1) 1903; Wright Brothers design/built their aluminum engine with a pre-mix vapo-chamber getting perhaps 1.5X more power output for flight.
2) 1920’s; G.A. Moore; US patent 1,633,791 (1927) for a vapo-carburetor that got ~35% more mileage over existent equipped engines.
3) 1930’s; C.N. Pogue of Winnipeg Canada, US patent 2,026,789 for an exhaust heated vapo-carburetor that demo’d 200 MPG.
4) 1940’s; J.R. Fish; vapo-carburetor, US patent 2,775,818, tested by Ford Motor company and showed 1.33X improvement.
5) 1970’s; Kendig Carburetor in LA; 2X mileage increase plus 50% pollution reduction, used a vapo-design heat exchange carburetor. 
6) 1972; A.L. Smith, NASA engineer; US patent 3,640,256, a vapo-carburetor, no reports on mileage.
7) 1973; J.R. Martin research engineer at Shell Wood River Refinery, CA; modified a 1959 Opel and won a mileage contest by driving 14 miles on 134 grams of gas, extrapolates to 298 MPG; engine well insulated and used a vapo-carburetor concept.
8) 1977; T. Ogle, El Paso, Texas; got 120 MPG (4X) on an evaporator-carburetor design using absorptive, wicking surfaces to evaporate fuel.
9) 1981; Henry “Smokey” Yunick. Daytona Beach FL, US patent 4,862,859, got 51 MPG (~2.5X) on a vapo-carburetor design where he modified a Pontiac Fiero.
10) 1984; J. Gilbert, Suffern, NY; built a gasifier-carburetor and got 2.5X increase in MPG using his 1981 Ford Escort control car.
11) 2011; G. Parker, developed the ALE, a 3-wheel plastic car; uses limited vapor-carburetion and gets 92 MPG plus reduced pollution.

I’ve picked the more outstanding accomplishments, there’s much more, but it will only bore you.
Kiteman RT-1011 year ago
No, where is your evidence that engineers have got it wrong? Where is your evidence about fuel vaporisation? Where is your evidence that the 92mph car got there through "proper" fuel burning, and not extreme lightness and low friction?
RT-101 (author)  Kiteman1 year ago

Unfortunately, your remarks clearly indicates you haven’t reviewed any of my suggested reading materials. I was fearful of this since some diligent research efforts are required, and I won’t spoon feed you. Forcing down bitter medicine never works without self discovery. With some due diligence, all of your questions would be logically answered. Of course, I’m not talking about simple concepts here, and so some technical homework would be expected on your part. Please do me the courtesy of reading some of this material. I suggest you at least review item-9, which can be found at: http://goo.gl/yGEa5 and if you have any further questions after reading that site, I’ll be glad to discuss them.

I’m not interested in providing a how to cookbook for casual parties. I want to stimulate good thinkers like yourself with enough information to eventually create a critical mass of informed public. A mass of people to challenge the car industry and big-oil as to why they’re not playing cricket with us, and what they can and should do to make a 100+ MPG car and help the world’s energy crunch.

Take a look at California Congressman D.Lungren, who recognizes the need for a technology stimulus by creating legislation that offers a $1B prize for some creative blokes to make a pure gasoline, non-hybrid car that gets over 100+ MPG; http://goo.gl/OSNHf    He recognizes that “Detroit” has too much to loose to make this happen for reasons of global oil partnerships and financial control. Lungren recognizes that the necessary inventiveness will come from mavericks with nothing to loose. While folks like yourself are being convinced that electric cars are our only salvation, nonsense! Figure out how much fuel (oil, coal, or natural gas gets burned to generate electric power) an all electric car really costs to recharge, and we’re not making any headway, particularly in pollution.

Kiteman RT-1011 year ago
He recognizes that “Detroit” has too much to loose to make this happen for reasons of global oil partnerships and financial control.

Oh, dear, now we're on that old conspiracy. Every single associated concern acknowledges that fossil fuels are running out, and need to be both conserved and replaced.

Figure out how much fuel (oil, coal, or natural gas gets burned to generate electric power) an all electric car really costs to recharge, and we’re not making any headway, particularly in pollution.

Absolutely none, if you are selective in your power generation methods. Wind, wave, tidal, deep-ocean current, biomass, hydroelectric, geothermal etc etc etc. can all be used to generate useful amounts of electricity, and thus power cars without using fossil fuels.

There is now only one barrier to mass switch to electric cars, and that is standardisation.

Just like every car manufacturer designs their engines to run off petrol with a particular set of properties - burn-speed etc - if they all sat down and standardised battery properties, petrol stations could become swap-out stations, and recharging your car would be even quicker than topping up the tank.


RT-101 (author)  Kiteman1 year ago

OK so I’ve finally got you thinking forward. Renewable sources of energy definitely needs to grow beyond the drop in the bucket it exists at today and will probably take another decade or two. Meanwhile Detroit can make vapo-cars operational in about two years with the proper political incentives.

Glad to see you got the message about vapo-cars. I hope to see you becoming an advocate of this “old” concept.  BTW I never claimed “vapo” burning originated with me, I’m just improving on its concept with key design features to make it a reality.

The vapo concept is more like 100 and not 50 years old. Your Peel link is irrelevant and misses the point. The Peel car doesn’t qualify on my approval list because while it’s “a nice toy” and gets over 100 MPG, it doesn’t use the “vapo-carburetor” concept and is just an enclosed, glorified motorcycle. Think of it this way; with “vapo” the Peel would get 3X or 354 MPG, or by making it into a “roomy” four passenger four wheel car, as challenged by  ; http://goo.gl/V2hxH  ,  it could still get its quoted 118 MPG!

My challenge to you is how would you go about creating an all vapor, 3X car engine? Do you think the 2X Yunick engine, which ran in a “real” 4-seater car and not a toy, was properly designed for vapo-combustion needs? Keep in mind it only got 51 MPG and not our 100+, albeit back in 1981.

Kiteman RT-1011 year ago
Hmmm.

You display ignorance about modern engine manufacture, and when caught out by proper engineers, you try and bluff your way out of it.

You try to encourage the use of fossil fuels, decry electric vehicles, and when I call you up on your false assumptions, you try and take the credit for my "forward thinking", without actually addressing any of my points.

Then you tell me that a "vapo" car will get 118mpg, on appallingly simplistic calculations.

Then you ask me how to build an engine like this.

I'm not here to be talked down to by fake experts. Get back to me when you have caught up with the 21st century, and are ready to work on replacing fossil fuels in transport, rather than encouraging it, but until then, this conversation is over.


On a personal note: I myself don't like overly electronic (battery driven) vehicles for the same reason I don't like the "energy saving" florescent widely sold....long term use will turn out to e be VERY ecco-UNfriendly. As a step in the interim, I don't see a problem though.
RT-101 (author)  Kiteman1 year ago

I’m disappointed you feel that way. If there are others that agree with your thoughts please step forward with your comments?

 I don’t mean to turn people off nor to talk down to anyone. If I get enough negative response over this from others, I’ll gladly address whatever points you feel are missing in my “appallingly simplistic calculations” and discussions. I want us to turn the page and act on your “until then” comment.

My intent is to provide knowledge so folks can make informed decisions about the best way to move forward with our limited energy resources.  And you’re quite right, this forum topic is not intended to replace fossil fuels, as yet.  Please visit my   http://goo.gl/rTUsz   to get some idea about generating renewable energy using desert sunshine, if that’s what intrigues you.

This forum topic addresses a way to prolong the eventual extinction of fossil fuels by a factor of 3X, by using more energy efficient IC-engines!  And as you pointed out, it should give us more time “to work on replacing fossil fuels in transport”, don’t you think?

I think the only way you’ll find out if I’m a fake or not, and if my “simplistic calculations” contain backup or not, is to continue down this fact finding path. I’ll gladly link you to whatever calculations you think you need. But for a meaningful discussion, please do me the courtesy of reviewing them and not dismissing them or avoiding them!  I am impressed with your 145 submittals, and just like all of your fellow linked followers, value your serious feedback and thoughts on this topic.  While your current feedback ‘just says no’, I believe that after reviewing the facts you may think twice about improving IC-engine efficiency, and prolonging our fossil fuel extinction time.

RT-101 (author)  RT-1011 year ago
On the topic of the KISS principle:

Remember what Mr. Purdue once stated:
“It takes a tough man to make a tender chicken”.

Likewise:
it takes a knowledgeable man to make complex concepts simple …
vis-a-vis simplistic calculations.
You can't get someone thinking forward.
People can only get themselves thinking forward.

Tip: the discussion would probably be a lot more constructive if you'd manage to avoid sounding condescending.
RT-101 (author)  Hack42Moem1 year ago
GUILTY as charged. I apologize!

Please understand that I'm highly motivated over this topic, and got carried away.

The fact that fellow engineers are willing to live on a diet of pabulum and not act by taking the next "great leap forward" disturbs me deeply. Alone I'm nothing, and without funding I'm even less than that!
Hey, I think you just got yourself thinking a bit more forward ;-)
Kiteman RT-1011 year ago
Oh, and your search for a 100mpg car is late. They invented those at least 50 years ago.
but he has substituted his reality already, what's the point?
The point needs to be made.

(Guess who's reading The Geek Manifesto?)
Tally ho, stick it to em.
tilting-at-windmills.jpg
Don Quixoteman, Man of East Anglia.
Coincidentally, home to one of the tallest wind turbines in Europe.

It's called "Gulliver", for no obvious reason...
Maybe because it is so big, it dwarfs all ofthers (i.e. Gulliver's Travels)
gmoon1 year ago
OK, so you postulate that the current efficiencies of internal combustion engines are hobbled by this one variable alone--insufficient fuel vaporization?

If this were so, then a natural gas fueled vehicle, since nat gas is already in a purely gaseous form when it's combusted, would be 3x as efficient, right? But that's not so--natural gas vehicles have decent mileage/efficiency, but nowhere near that 3X increase when compared with petrol...

Also, natural gas has a higher energy density than gasoline, so if this concept was accurate, we'd see an even greater increase. But we don't.

Sure, IC engines can still be improved, but it's diminishing returns at this point...
RT-101 (author)  gmoon1 year ago

1)      TWO VARIABLES:  Not just poor fuel vaporization, but the poor timing results needed to properly detonate that fuel at the max piston positioning for max engine torque as noted above.

2)      CNG ENERGY DENSITY:  Compressed Natural Gas (CNG) isn’t 3X efficient because it has lower not higher energy density than gasoline. Energy density for CNG varies with its pressure density. At standard temperature and pressure (STP), where pressure is 1 atmosphere or 14.7 psia., its energy density is only 900 BTU/Gallon of gas volume, so they pressurize it to 3600 psia where it attains 31,000 BTU/Gal-Volume. CNG engines receive their fuel-gas at elevated pressures to keep energy density as high as possible, but still lacking. Now compare this energy density to gasoline which comes in at 114,000 BTU/Gallon, and diesel at 129,500 BTU/Gal !

3)      So while with CNG we rightly combust 100% of the gas-fuel and at the proper timing, its energy level is so much lower than gasoline, giving it little room for any performance improvements.

4)      WHERE DOES 3X COME FROM:   Gasoline and diesel fuels contain an amazing amount of energy density compared to any other hydrocarbon based fuel.  Do a calculation of the energy required for “equilibrium travel” of a car on a flat, straight road at say 60 MPH. Let’s consider aero-drag, rolling road friction, other mechanical frictions, wasted heat from engine (radiator, exhaust), gearing losses, engine inefficiencies etc., and add these consumed energies while traveling over a given distance. Now compare that to the actual amount of fuel consumed by that vehicle in terms of GPH and BTU’s burned (at 114,000 BTU/Gal) and you will get at least ~3X more available energy from the fuel than is needed to propel that car over that distance. Why, is it magic? Where did the remaining energy go to? The numbers don’t lie and they don’t add up!

gmoon RT-1011 year ago
I don't think these term mean what you think they mean...

1) With electronic ignition, timing is the easiest variable to alter. It's been done--optimized, tested and retested for decades.

2) You cannot compare unequal units like this (unless your goal is to deceive). Nat Gas has a higher energy density by weight (by mass, actually).

3) The stoichiometric combustion ratios of the two fuels (percentage of fuel by mass) are--

Gasoline: 6.8%
Nat gas: 5.8%

--which is nearly identical. Since Nat Gas has a slightly higher specific energy (energy per unit mass), the two fuels would be nearly identical in a real comparison.

4) Research "thermal efficiency." That's the real limitation.
RT-101 (author)  gmoon1 year ago

Good discussion, forgive my wordiness:

1) ELECTRONIC TIMING & THERMAL EFFICIENCY: I agree with both your timing and thermal efficiency statements. Let’s look at “electronic timing” (may be wrong words usage here) differently. If I burned pure vaporous gasoline then your timing statement is correct. But that’s not what we do today. IC-engines inject liquid droplets that require a phase change to vapor before they burn. Transient modeling of droplet-to-vapor formation suggests it takes a finite time for this to occur based on various factors of: a) pressure, b) both transient wall and fluidic mixture temperatures, c) heat transfer probability of droplet fractions and their size touching heated walls, d) resultant vapor formation and its phase-change affect upon non-wall-touching droplets, etc. OK, so it takes time to turn un-useable liquid fuel into useable vapor for combustion. This “thermodynamic timing” conflicts with “engine timing”, which is fixed mechanically based solely upon RPM, and our electronic ignition timing. Thermodynamic timing stands in the way of getting properly timed energy release after injecting fuel droplets as opposed to vapor. This results in ~2/3 of our fuel combusting at a thermodynamic timing that converts to useless engine torque.

2) UNITS COMPARISON & DECEPTION: No proceeds in communicating deception? Based on specific energy or energy per unit mass, CNG (at 245 atm and 0 C) is 26% higher than gasoline as you pointed out. But that’s uninhibited chemistry with CNG at 245 atmospheres. The real world unfortunately contains physical limitations. How much CNG mass and at what actual arrival pressure can we really dump into the engine cylinder volume within our allotted mili-seconds of mechanically induced time. Gas expanding shock waves are created to dramatically reduce local gas static pressure and consequent fuel heating values by up to ~50%. Adjustments to local specific energy values now need to be made that are now based on actual “energy density” formulations which are highly sensitive to actual pressure conditions within the engine cylinder. That 26% margin quickly turns into double to triple energy reduction factors, which are generally acknowledged for CNG type fuels.

3) THANKS FOR AN “AH-HAH” MOMENT: Our exchange triggered something! Based on your specific energy point, both CNG and cryogenic LNG wins over gasoline. So let’s take advantage of this and another point. That being the injection of cryogenic LNG droplets, as we would gasoline, with the possible benefit of a thermodynamic edge in phase change timing over today’s gasoline phase-change? LNG droplets are as easy to inject as gasoline, contain 26% more energy than gasoline and only needs modeling to ascertain its phase change timing requirements. Droplets will also avoid CNG gas performance limitations from energy density dependence on pressure. This warrants looking into even with its limiting cryogenic operation!

gmoon RT-1011 year ago
Cutting to the chase--without continuing to argue specifics of theory from a layman's POV-- it's doubtful that much more efficiency can be squeezed from a piston style internal combustion engine.

That's not to say that other engine technologies couldn't improve on those numbers...
verence1 year ago
To answer your question: Yes.
http://en.wikipedia.org/wiki/Volkswagen_1-litre_car

For the efficiency related wall-of-text: Engineers at all car producers around the world are working on it.
RT-101 (author)  verence1 year ago

Firstly, sorry for not getting back to you sooner!

This Volkswagen XL1 concept car is very impressive. I read your link and it gets 235 MPG! My only remark is that it is a diesel engine powerplant. We all know that diesels get better gas mileage because of higher compression ratios resulting in faster detonation speeds (Fig-1, above), and that’s why they exist.

Since the concept of vapor burning works with any internal combustion engine, and as the XL1 only uses conventional diesel injection and combustion techniques, amazingly there is still marked room for improvements here.

Their engine uses fuel droplet injection, had it used vapo-injection it would have the potential of improving mileage by a factor of roughly ~2X (3X for gasoline engines, ~2X for diesels). This produces a mileage of ~470 MPG, amazing isn’t it? And of course, lightweighting, improved aerodynamics, etc. all come to play here, along with the big multiplier of vapo-combustion!

Good grief, you really don't know ANYthing about engine design do you ?

MOST modern engines don't even use the Otto cycle anymore (c.f. "Miller cycle" or "Atkinson cycle")

What do you know about homologous ignition ? Lean-burn ?
RT-101 (author)  steveastrouk1 year ago
Please keep an open mind about what I am saying and you’ll realize that whether one uses the Atkinson or Otto cycle engines, they bought require gasoline combustion. It doesn’t matter whether it takes one or two cycles to complete the process, my combustion concept will improve the performance of both systems by about 3X. So if Atkinson is say 1.5X better than Otto then Atkinson improves by 3 x 1.5 = 4.5X and Otto by only 3X. BTW the reduced residence time of the Atkinson cycle combustion process requires even further expectations of improved combustion response time, and my approach is designed to truly solve this problem as apposed to only playing with timing ignition sequences.

PS:
Homologous ignition is a band-aid because today's injected fuel is liquid not vapor. Vapor combustion allows the leanest F/A possible, typically 2X to 3X leaner than fuel droplet injection combustion of today.
lemonie1 year ago
You seem to have a deranged "knowledge" of engines, perhaps best identified by Today's gasoline engines are not designed to combust/burn gasoline efficiently, and Engine designers assume. explosive  is also inappropriate.

Anyway, what is your idea for pushing thermal-efficiency closer to 100%?

L
RT-101 (author)  lemonie1 year ago
Thanks for the indirect compliment.

Preamble:
If I expounded conventional wisdom for improving gasoline engine performance, and used the circular reasoning of others, I would be stuck with using the same electric motors that everyone else swares by. If I told you what I used to do for a living concerning combustion and engines it would: 1) turn you off for possibly viewing it as bragging, and 2) maybe give me some credibility but it would be totally destroyed by number-1. So either way I would loose trying to communicate thoughts to folks and eventually force the oil/car industry to start producing a better product that will actually go over 100 MPG without the need for hybrid designs as yet!

ANSWER: The following is winded because of its complexity in answering you...

BTW, technically I'm not improving thermal-efficiency, pretty much all of the gasoline gets combusted today. That means the energy of the fuel is almost totally released, but not effectively used. The problem is the timing it takes to convert fuel-injected gasoline droplets into vapor to combust at the correct engine rotational time and extract that expended energy. If you did the math for any size engine rotating at say 3200 RPM, you would find that a 4-stroke engine can only extract that energy from combustion during one of the four strokes. And the time it takes to make that stroke happen is only 9.4 thousandths of a second or 9.4 milisecs (msecs).

Now picture the piston just below TDC, all its valves closed, under pressure and containing all the fuel and air it needs to combust. At this point our deadly cocktail has about half of the 9.4 or about 5 msecs to complete combust after the timed sparkplug ignites it. The half factor exists because the max portion of our power stroke (moment arm) occurs at the mid-stroke of the piston sliding down and turning the crankshaft. If all of our fuel isn't combusted by then, the moment-arm or distance from the piston-center to the crankshaft quickly reduces to zero. Again only vapors combust, and fuel droplets take a relatively long time (>5 msecs) to vaporize before it can combust. Unfortunately nature is stubborn and vaporizes ~2/3 of our injected fuel droplets only during the second half of the power stroke. So this huge amount of energy gets wasted because even though the forces of combustion are huge, its moment arm is rapidly approaching zero. Infinity times zero is still zero!

My Solution Idea to Fix the Above = as stated earlier "only fuel vapors combust almost instantly and easily within 5 msecs"
Sounds like a good start to a thesis. So what do you propose we do about it? Do you have any ideas that other engineers haven't thought of yet? Maybe the problem isn't the engine design itself but the fuel we're using. Maybe we need to be heating the gas before it reaches the injectors. Maybe we should be using Gas Turbine engines instead of ICs. Though there are engineering challenges to that as well.
RT-101 (author)  mpilchfamily1 year ago
My compliments to you, you're on the right track:

"maybe we need to be heating the gas before it reaches the injectors"

Actually heating and phase-changing the gas!
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