Synopsis: Install a boiler in the fuel line. Gaseous gasoline is injected under pressure into each cylinder at two or more places. The combination of hot compressed air in the cylinder plus hot gaseous gasoline automatically ignites, no spark plugs needed. Because the fuel is perfectly vaporized, it burns more cleanly, and engine power goes up.
Details: In the diesel engine, a large amount of air is compressed such that it acquires a pretty high temperature. The diesel fuel is injected as a spray. The hot air automatically starts burning the fuel.
However, there is a side effect. Think of those spurts of carbon black that you see coming from a diesel exhaust -- they happen because DROPLETS of sprayed fuel burn from the outside in. By the time the "cores" of the droplet start to burn, the available oxygen in the vicinity of those cores is so low (I'll call it "local oxygen deprivation") that only incomplete combustion occurs. In hydrocarbons, hydrogen has a greater avidity for oxygen than does carbon, so the carbon is what is left behind, and is what goes out the exhaust.
It is known that the smaller the droplets, the more completely does the fuel burn. A major purpose of the old-fashioned carburetor was to spray fuel into a moving flow of air sufficiently early enough before it entered the engine cylinders, that most of the sprayed fuel droplets would vaporize more completely.
Some gadgets (you must have seen one of those "Tornado infomercials", haven't you?) are intended to increase the mixing of fuel and air, before it enters the cylinders, just to promote that fuel-vaporization (minimizing droplet size). To whatever degree such gadgets actually accomplish that claim, that is the degree to which a car might get better gas mileage.
Well, if we want vaporized gasoline mixing with air, why not just BOIL the gasoline? A small boiler, electrically heated, can yield enough vapor to start a car quickly even on very cold days (and such days do not encourage natural fuel-vaporization in the least). When the engine warms up, of course, it generates quite sufficient heat to do the boiling, no electricity needed.
Now, I am fully aware that if we boil the gasoline, we risk spontaneous combustion if the fuel was mixed with air in a carburetor. Therefore we have to abandon the carburetor, and switch to fuel injectors. More, we have to use fuel injectors that are specifically designed to handle compressed gas, and not liquids.
Having done the switch, it makes sense to have multiple injectors per cylinder, just as today we have multiple intake and exhaust valves per cylinder. We want the sprayed gaseous fuel to encounter compressed air in such a way that no semblence of local oxygen deprivation can occur -- so injecting the fuel at just one place is completely inadequate.
As already mentioned, the combination of compressed air and boiled fuel should be entirely adequate for combustion to automatically happen, as reliably as a diesel. But since this proposal will lead to practically perfect combustion, it follows that engine power will be maximized, and hydrocarbon pollution emissions will drop to nearly zero, and no expensive catalytic converter will be needed.
POSSIBLY even the nitrogen oxide pollutants will be reduced, too. Those are formed under high temperature conditions when the oxygen in the compressed air is so ready to react with something that it latches onto the nearest nitrogen before any of the fuel gets to it. (Normally 80% of air is nitrogen, remember, and perfectly pre-mixed with oxygen it is, also)
Well, with multiple spray points, NO hot spark, and relying on the temperature of the fuel to help begin combustion, we might expect nitrogen oxide pollutants to be reduced too. So, will somebody build one of these and find out?-- Vernon, Oct 13 2003 A History of Vapor Carburetors http://www.keelynet...energy/gunnhist.htm"Using heat or mechanical agitation to more completely vaporize the gasoline before it enters the intake manifold can result in more efficient operation and a reduction in unburned hydrocarbons." [phoenix, Oct 04 2004, last modified Oct 21 2004] (?) 300 MPG Carburetors...is there such a thing? http://www.phact.org/e/dennis27.htm"Fuel combustion today typically exceeds 97 percent." [phoenix, Oct 04 2004, last modified Oct 21 2004] Automorrow http://www.automorr...articles/links.htmlMore alternate power ideas. [phoenix, Oct 04 2004, last modified Oct 21 2004] Diesel Fuel Heaters http://www.maesco.c...ro/r_dfh_intro.htmlWarms up your fuel while it is in the fuel line, ostensibly to prevent diesel fuel from gelling in the line. [Laughs Last, Oct 04 2004, last modified Oct 21 2004] Nitroglycerine Engine http://www.halfbake...oglycerine_20EngineHB annotations converge. [Laughs Last, Oct 04 2004] Effect of pressure on boiling points http://www.ch.cam.ac.uk/magnus/boil.htmlAn applet that calculates boiling point at any pressure, given the boiling point at one known temperature. [Basepair, Jul 06 2005] unique air injector principle of fuel introduction Perfect_20Engine_20...omotive_20X_20PRIZEboiler and multiple injectors are much simplified. [rotary, May 21 2008] Baked http://en.wikipedia...iki/Hot_bulb_engine [goldbb, Feb 10 2009] 64MPG http://www.technolo...m/energy/24701/?a=fFrom the article: "The key is heating and pressurizing gasoline before injecting it into the combustion chamber." DUH! [Vernon, Mar 09 2010] Pressurized Fuel Injection http://news.slashdo...on-System?art_pos=4 [cowtamer, Mar 09 2010] "Horse's Mouth" link http://www.tscombustion.com/This is the company that made the announcement that was mentioned in the "Technology Review" article, and in turn reported on "Slashdot". [Vernon, Mar 09 2010] Superspray http://books.google...0superspray&f=falseI remember reading this when originally published. The basic idea is that finer fuel droplets burn better. All I've done with this Idea is extrapolate the fine-ness of the droplets to the size of individual molecules. [Vernon, Mar 10 2010, last modified Mar 17 2010] LNG http://www.envocare.co.uk/lpg_lng_cng.htmWhy heat gasoline ? [8th of 7, Mar 10 2010] Vapor carb https://www.youtube...watch?v=Oqg0Y9t3CAYSucking air through gasoline to make fuel vapors. [travbm, Oct 31 2015] I suspect different gasolines have somewhat different boiling points, because of the secret additives. Note that those additives are designed to do some of the same things that I described being accomplished with boiled gasoline. This makes all those additives a waste of money, and after their removal, "commercial branding" of gasolines totally meaningless. Oh, and gasolines with different octane ratings will probably also boil at somewhat different temperatures, because such fuels are differently proportioned mixtures of different hydrocarbons.
Anyway, here is a list of simple hydrocarbons, and their boiling points, in Celsius degrees: Methane (CH4) -162 Ethane (C2H6) -89 Propane (C3H8) -42 Butane (C4H10) -1 Pentane (C5H12) 36 Hexane (C6H14) 69 Heptane (C7H16) 98 Octane (C8H18) 126 Nonane (C9H20) 151 Decane (C10H22) 174
All of those feature simple straight chains of carbon atoms, surrounded by hydrogens. There are plenty of variations (T-shaped molecules, for example), and a mixture of variants goes into the making of gasoline. In case you didn't know, pure octane has a combustion-energy rating of 100, and all gasolines are compared to that value.
I am confident that a good enough boiler will boil all the fuel components of gasoline quite well, without regard to the actual molecules boiled off. Indeed, when completely boiled, the collection of differing hydrocarbons will be as completely mixed as they were in the liquid state, so, no effective difference when burned!
I do need to mention one additional detail. Consider butane, with its boiling point almost the same as the freezing point of water. Yet those little butane cigarette lighters all have LIQUID butane in them! The reason is that the butane has been pressurized, and many substances have higher boiling points if pressurized. So, for a boiled gasoline engine, we want to make sure we have heated it up enough to STAY gaseous, even under the pressure of the fuel injectors. Otherwise fuel droplets would form again, meaning that the goal of complete combustion will not have been achieved.-- Vernon, Oct 14 2003 //"commercial branding" of gasolines totally meaningless//
You might be surprised how similar gasoline from different companies can be. In my country it all comes from only one refinery, run by one company, but is still sold under a variety of brand names. I guess this is common practice in other areas too.-- suctionpad, Oct 14 2003 half, regarding your uncle's non-exploding carburetor, I'd say he only warmed the gasoline enough to encourage its natural evaporation rate. That is probably why it was safe. I doubt he heated it enough to stay gaseous under the pressure inside fuel injectors.... As for injecting air, that seems redundant, unless air injection is used INSTEAD of ordinary intake valves. But then you might as well be using a supercharger with ordinary intake valves...I suppose it depends on which scheme, overall, is less complex.
suctionpad, no, I'm not surprised. While I know that the main difference between branded gasolines is the additives, I also know that plenty of products on the market are similar to gasoline in that far fewers manufacturers exist than brand names, for those products.-- Vernon, Oct 14 2003 OK, Thanks, phoenix! That's half of this Idea shown to be already out there. I kind of wondered, after I perhaps independently thought of it, why I had never recalled seeing it in all those years of Popular Science...but if it was there, then of course that "independent thought" WAS a recall.
However, that still leaves the other half of this idea, as using the heat of the boiled fuel to remove the need for spark plugs (and their wiring, and the high voltage system...). Remember, this is distinct from a diesel, even though a diesel also uses fuel injection. The diesel's ignition occurs almost entirely as a result of the heat of the air it compresses (there are also little gadgets called "glow plugs" to help, I think).
By the way, phoenix, If fuel combustion today typically exceeds 97%, then that is certainly better than I expected, when I began writing this down. But is that figure really true? The linked article cites a single source, and I have been unable to corroborate it. Thanks.-- Vernon, Oct 14 2003 Not sure I expressed my point sufficiently there, although this is maybe heading a bit off topic. Where I come from there is no difference between (for example) Shell, Esso (Exxon), BP, Texaco or any other kind of gasoline when it leaves the refinery. It all comes out of the same chemical plant, and into the waiting tankers. No special additives for any of the brands (apart from Shell I think, who will pour some detergents in as well, but not at the refinery). Always made me wonder what the point of the different adverts was ("buy our fuel and your car will run faster/more efficiently/for longer etc.").-- suctionpad, Oct 14 2003 Just a couple of points: 1. don't intake manifolds already have ducted water from the "cooling system" to heat the petrol up and encourage it's vapourisation? 2. why not simply use Enviro Diesel, diesel not made from mineral oil but from vegetable oil (called Envirodiesel in parts of Europe and Australia (I believe)). I'm not sure if it is a conspiracy theory or not but I have heard that the diesel engine was originally designed to run on vegetable oil diesel and those whacky and zany funsters from the Oil Companies made sure that it was changed to mineral oil based diesel.-- Peticelli, Oct 14 2003 Laughs Last, I see from your figures why diesel autoignites while being sprayed as a liquid and it makes clear that for sprayed gasoline to autoignite, its temperature does have to be higher than the boiling point. (One might ask why does "knocking" occur in a gas engine, but this has largely been traced to waste products that have stuck onto the inside surface of the combustion chamber, and have stayed hot from the prior combustion cycle.)
suctionpad, yes, I know that iw what you meant. But I'm sure that Shell isn't the only oil company that adds proprietary additives, after receiving the generic fuel from the refinery.
Peticelli, intake manifolds these days are arrying only air, and many cars are being made with fuel injection. But preheating the air is OK, since it effectively leads to even hotter compressed air in the cylinders, before the fuel is sprayed across the spark plugs.
As for envirodiesel, I do tend to think it will catch on, but its large-scale adoption depends on producing and distributing vast quantities of the stuff. An entire network needs to be in place, just like the existing mineral-fuel network.-- Vernon, Oct 14 2003 Ouch. Half-baked engineering. Where to start? (1) It's a common misconception that fully evaporated gasoline before combustion is a goal. Fuel droplet size and dispersion, along with valve and ignition timing, combustion chamber shape and compression ratio, are designed parameters in order to achieve the optimum combustion rate, which is a function of engine RPMs among other things. Too high a combustion rate results in destroyed piston tops, crank bearings, valve heads, etc. Flame-front travel through fine gasoline aerosols under moderate compression is in the required velocity range. Flame-front travel through gasoline-vapor-air mixtures under compression is generally fast enough to exceed the mechanical propogation rate for air, i.e. a shock wave or detonation front (2) The reason that extreme compression of gasoline-air mixtures to self-ignition conditions is not done is that the resulting combustion is an uncontrolled detonation. No practical engine can survive continuous detonation within itself. (3) Fuel economy is maximized by complete combustion, but this is not so hard to achieve; many practical engine design families approach 100% during steady-state operation, most notably some of the Japanese approaches to California ultra-low-emissions rules (4) Power is maximized **not** by complete combustion per se, but by combustion of the maximum amount of stoichiometric mixture per fired cylinder. Complete combustion is useful, but any practical engine designer shoots for getting more charge into the cylinder...the gains are much greater. Because of the highly nonlinear relationship of gas density to temperature, this requires **cooling**, not heating, the cylinder charge--both air and fuel. The volumetric expansion ratio for gasoline that has been heated to a high enough temperature to fully evaporate all the hydrocarbon blend constituents will be at least 10x compared to the same volume of fuel in aerosol form. I don't have handy to me the expansion ratio for air at whatever rather high temperature this might require, but a guess of 5x might be close. Thus either the cylinders will have to be 5x to 10x the displacement for the engine to combust the same mass of fuel-air mixture per cylinder-fire, or if displacement is lesser, the engine will produce proportionately less power. (5) Sometimes heating capability is added to fuel rails, with appropriate thermostatting, to bring winter fuel up to a design temperature range so that the engine computer doesn't have to handle quite so wide a range of combustion rates and ratios. However, this is never used to get the fuel any hotter than "cool". (6) Want simple evidence? Review the design of cars that deliberately run on gaseous hydrocarbons, i.e. LPG or propane. Such designs generate a fraction of the horsepower of a gasoline engine, because the less-dense charge results in lower mass of charge per fired cylinder...and this is with considerable *cooling* of the charge from the temperature drop that occurs when gas is released from pressurized storage conditions. Take such an engine and install a heater in the gaseous fuel line to simulate boiled gasoline, and power will drop precipitously.-- JWilly48519, Oct 15 2003 Merck Index indicates a boiling point for gasoline anywhere from 32 degrees C to 210 degrees C.-- mitcheroo, Oct 15 2003 You could use the Gasoline to as a coolant around the engine block and after it circulates around the engine it will then be used in the boiler, this would save energy and help cool the engine.-- JoeLounsbury, Oct 15 2003 JWilly48519, thanks for the info. One aspect of the detonation problem that you describe, however, seems to me to be something that you have overlooked. Detonation can only occur in a volume of MIXED air and fuel. In this engine, both are separated until the gaseous fuel is injected. Any detonation front will be limited to the rate of spray of fuel, and it cannot backup into the fuel injectors (no oxygen there). Thus this engine would have a kind of controlled detonation, which would not be as harmful as you describe.-- Vernon, Oct 16 2003 Isuzu is currently using a Gasoling Direct injection system to inject fuel DIRECTLY into the cylinder, not behind an intake valve. The results are simmilar to what you propose. Secondly, what you describe as a boiler is actually a VAPOR LOCK condition that can happen on very hot days in older carburetted vehicles. Not a good situation to have.-- bender, Oct 16 2003 bender, the vapor lock problem can only exist in cars in which the flow of gasoline to the cylinders is much more passive than would be needed here. Vapor lock means (if I understand/recall it correctly) gasoline vapor has backed up from the engine through the fuel lines and reached beyond the fuel pump, so that it no longer in contact with the liquid it was designed to handle. Here, because we are designing to handle gases, it is likely a one-way valve will be included, to ensure boiled gasoline cannot get at the main fuel pump. Also, a better quality more-tightly-sealed pump will handle vapor as well as liquid.... Next, the gaseous fuel injection system also means there will be compression by another pump. Since this most certainly has to handle gaseous matter, you can be sure it will be designed so that there will be no vapor lock here, either.-- Vernon, Oct 16 2003 One big problem with heating the fuel to its ignition point is that a pinhole leak in a fuel line would become a giant blowtorch in your engine compartment.-- GenYus, Dec 03 2003 GenYus, most every notion has a weakness. In this case a pinhole leak could qualify, but how likely are they going to occur in plumbing designed to handle the pressure? And, the region of weakness is between the fuel pressurizer and the fuel injectors (with boiler somewhere in between). This could be a reasonably short distance, depending on design.-- Vernon, Dec 04 2003 For high thermodynamic efficiency you want the coldest intake possible, so you'd have to balance that motivation with the desire to have vaporized fuel. Anyway, for heating the fuel, what about using the fuel to regeneratively cool the engine, as in rockets; use engine waste heat rather than a power-robbing electric heater.-- TerranFury, Dec 16 2003 TerranFury, in the main text of the Idea is this: "When the engine warms up, of course, it generates quite sufficient heat to do the boiling, no electricity needed."
That is part of a paragraph that considers what to do on cold days. An electric heater is mentioned. A combustion heater might be better (no battery draw).-- Vernon, Dec 16 2003 Sorry but this idea is baked, extant and expired. Our library has a copy of: "Brown's Book of Carburators" listing many patents. Methods of heating and better atomizing gasoline are well known and they work, only the automobile companies don't want you to know because they and the oil companies (who make the gas,) have conspired not to let you have them. Just do a patent search of "fuel vapor systems" on www.uspto.gov and you'll see what I mean.
Anyone ever smoked on a bong? (Not me!) ...anyway that's the best principle. Replace the water for gasoline and heat the mason jar for goodness sake!
Nature is a free lunch.-- thrival, Jan 07 2004 Thanks!-- Vernon, Apr 28 2004 I hate to burst your bubble Cart123948, but adding a heater to the fuel line of an existing liquid fuel injection system will only result in slightly hotter gasoline. The gas that is in your fuel rail at any given time is not there very long at all. The fuel pressure regulator restricts the flow of gasoline from the pump just enough to provide the necessary pressure for proper fuel injector operation, and bypasses the rest of the supply from the pump back to the fuel tank. The gasoline that continually passes through the fuel lines on your vehicle will not stay in one place long enough to become heated to its boiling point; especially as it is already under pressure to the tune of 30-60 psi, depending on the system. And as we all know, placing any liquid under pressure raises its boiling point, further hindering your efforts. Otherwise, it was a good idea in theory.-- IHRAcer, May 28 2004 Maybe if there were a primary "explosion" to atomize the fuel, then ignition, like a thermobaric bomb... Just a thought.-- mailtosalonga, Aug 11 2004 IHRAcer, it is quite possible to add sufficient heat to a flowing liquid. One modern energy-saving hot-water maker is exactly such a thing; it's located just before the tap, and when water flows, this activates a heating circuit. By the time the water that is entering the device has exited, it is how enough for the tap. NO TANK to wastefully keep warm.
Also, with respect to gasoline, the purpose is NOT to boil it before it reaches the engine; the purpose is to put so much heat into it that WHEN it is sprayed into a cylinder, it instantly vaporizes, rather than dropletizes-- Vernon, Aug 12 2004 Because of the idea that only gasoline vapors will burn, it has led towards trying to vaporize as much of the originally liquid gasoline as possible before the combustion process takes place. Which means trying to get as much of the gasoline as possible to actually burn and converted into heat and pressure, and cutting down on wasted unburnt fuel that goes out the tailpipe, adding to the exhaust emissions.
Heating up the liquid gasoline in the pressurised fuel injection rail may work. When the injectors open up and release the preheated fuel into lower pressured area of the combustion chamber / cylinder upon the intake stroke cycle, the fuel would have a higher tendency to vaporize. With electronic fuel injection incorporating a closed loop operation involving the oxygen sensor at the exhaust end, the initial effect would be having those extra vaporized fuel being burnt. Thus, the engine management system would 'think' that the air-fuel mixture is richer than the ideal stoichiometric ratio, and hence, proceed to 'lean back' the mixture by reducing the pulse width modulated duty cycle of the fuel injectors. That would mean a reduced rate of volume of fuel being consumed by the engine, translating into better fuel economy.
About heating the intake manifold, I have personally experienced the difference in heating it and not heating it. A decade plus ago, I drove a used early model carbureted Japanese import. Comparing it to an exact same model owned by a fellow worker, mine had gotten very noticeably worse fuel economy even with similar driving conditions. When I was replacing its old and deteriorating coolant hoses, I discovered that the previous owner had the coolant passages to intake manifold blocked. I unblocked that and found that the fuel economy had improved to the level my fellow worker's car was getting.-- rthlng, Aug 12 2004 rthlng, gasoline vapors EXPLODE when mixed with oxygen and ignited; gasoline droplets merely burn. The internal combustion engine is designed for explosions, of course. If too much fuel is exploding, then the obvious thing is to throttle back, and save fuel -- but get the same total explosive force as before the fuel was vaporized.-- Vernon, Aug 12 2004 Surely the volumetric efficiency of the system would fall considerably if fuel was introduced as vapour? Intercoolers are designed to lower the temperature of the charge entering the cylinder, so that a larger mass of mixture can be burnt. This would seem to defeat such efforts.
Also, I fail to see the advantages of this. Modern stratified charge/lean-burn systems give near-total combustion already.-- david_scothern, Aug 13 2004 david_scothern, you are correct in that merely vaporized fuel cannot compete in terms of quantity of molecules per volume, as the liquid form. However, I have specified that the boiled fuel here be pressurized, and if hot enough, such a pressurized vapor can be NEARLY as dense as a liquid. The remaining difference should translate to overall reduced fuel usage.-- Vernon, Aug 13 2004 If it worked, we'd be running out cars on butane and propane instead of liquid gasoline. Actually, there are conversion kits to run gasoline engines on alternative gaseous fuels such as propane, butane, methane, etc., and many municipal vehicle fleets use such fuels. My brother-in-law has used propane in his personal vehicle since the 1970s. (If you're driving around in Michigan's UP, avoid red Ford Broncos!! Danger, Will Robinson, Extreme Danger!!!) This boiling gasoline idea dates back over 100 years, when it was thought that preheating the air/fuel mixture would improve fuel efficiency. It didn't. Electronic fuel injection in lighter vehicles does work, and it's getting better. Automobile diesels may use indirect injection and glow plugs as the ignition source. Direct-injection diesels, such as used in large trucks and earth-moving equipment, use compression as the sole source of ignition heat. (to give you an idea of how much heat compression can generate, consider a spacecraft reentry- it's heated by compression, NOT friction, to very high tempuratures.)-- whlanteigne, Oct 26 2004 You're missing the point. If you know that you are going to be exposing more fuel to the oxygen, because the fuel is vaporized, that means you can inject LESS fuel. A "lean mix" is generally good, but a COMPLETELY BURNED lean mix is better.-- Vernon, Oct 26 2004 [Erion929], you seem to think that the gasoline is to be boiled while being exposed to the air. NOT! The boiler is to be sealed and able to withstand appropriate pressure. It ALSO does not need to be very volumous; it only needs to boil the fuel as fast as the compressed gaseous fuel is wanted by the injectors. (And yes, of course the liquid-fuel pump has to be powerful enough to keep the boiled fuel going the right direction.)
Next, the energy efficiency of an engine is NOT so related to the type of fuel used as you seem to indicate. The engine converts heat energy into mechanical energy, and the source of heat matters not at all. Gas engines are typically 35% efficient or so; Diesels (and Stirlings!) are over 40% efficient. In ALL cases (including black smoke from diesels), you will get better FUEL efficiency if ALL the fuel is actually burned (at the engine) to make heat (and not away from the engine, as [Howard] below indicates happens in a catalytic converter -- which gadget should be less-needed if combustion is completed at the engine!).-- Vernon, Dec 13 2004 [Vernon] did you delete my on-topic anno? The point I made was that, if you boil gasoline at atmospheric pressure and then try to force it under pressure into the engine, the pressure will simple re-condense it on the spot.You would need to find the boiling point of gasoline *at engine pressures* and then heat it to at least that temperature.-- Basepair, Jul 05 2005 [Basepair], I don't recall deleting anything here, or even looking at this Idea for the last few months. Regarding your current anno, you are forgetting that the pressurized air in the cylinder is HEATED by its compression. Between that and the temperature of the boiled fuel, I expect immediate combustion to occur. Remember, "knocking" is something that can happen even without a spark, and without preheating the fuel.-- Vernon, Jul 05 2005 Ooops - apologies for wrongly accusing you of deleting. I did post the annotation in question, but it somehow vanished.Perhaps I mis- understand, but you are wanting to boil the gasoline at something like normal pressure, then force the vapour into the cylinder under pressure - is that right? If so, then my point is that the vapour will not remain a vapour in the 'injector' (or whatever device you use to drive it into the cylinder) - the pressure will recondense it before it reaches the hot cylinder. Yes, I know that compressing a gas raises its temperature, but not sufficiently to prevent this condensation. You will need to heat the gasoline to a much higher temperature than that which is needed to boil it at atmospheric pressure.-- Basepair, Jul 05 2005 [Basepair], you must have missed something in the original text, then. I wrote: "...we have to use fuel injectors that are specifically designed to handle compressed gas, and not liquids." I'm pretty sure I implied that the boiled gasoline was supposed to be hot enough that it would NOT condense when squeezed into/through the fuel injectors.-- Vernon, Jul 06 2005 Ah, fair enough then. What pressure are you going to have to inject against (I mean, the pressure in the cylinder at the time of injection?). At 10 atmospheres, decane will have a boiling-point of 292°C, and this will become higer still as the pressure rises. But I guess these temperatures aren't out of the question.There is an applet that lets you calculate boiling points at different pressures (if you know the boiling point at, say, atmospheric pressure), see link.-- Basepair, Jul 06 2005 Thanks!-- Vernon, Jul 06 2005 I agree that it is necessary to boil gasoline into vapor (that is vaporize gasoline) for complete combustion to reduce pollution. But why alway using carburator ? Carburetor is obsolete and is not compatible with current modern car, and that is why auto manufacturers are not willing to use vapor carburetor even though it really saves gas and increase mileage. Therefore, is there any way that can apply this fesible theory on fuel injection system? Any good idea or design using fuel injector instead of using carburetor? I am currently looking for information in this field from internet and for patent office. Is there anyone here can give me links if you ever see design using fuel injector?-- John1973, Dec 16 2005 [john1973] you could type " vaporized fuel injection system " in yahoo and google search engine for more information. There are many interesing sites disscussing about vaporized gasoline fuel that greatly improves fuel economy and reduce exhaust emission. I recommend you to visit sites such as http://freeenergynews.com/ for concept of why it really increases fuel economy and reduces emission if you are interested. I also suggest you to take a look at a novel and interesting conceptual design of fuel injection system at www.vfis.us .The site clearly describes how it is implemented to be compatible with current popular fuel injection systems such as gasoline direct injection or port injection. The conceptual injection system is simple in design, and inventor claims that it will outperform gasoline direct injection system in fuel economy and exhaust emission. So what do you think about the claims inventor made? I hope you like the sites and hopefully give me some of your opinion about it.-- JimCarrey, Dec 18 2005 [JimCarrey] Thanks for your link of vaporized fuel injection system. The design is quite different with those previous designs that use vacuum pressure to promote fuel vaporization for use in carburetor, and this one uses waste heat energy to vaporize gasoline to high-temp and high-pressure state for fuel injection purpose. The design is novel and simple , how come nobody including me : ) thinks of this method before. If , according to what the inventor claimed, only around 13% of gasoline is actually used to drive a car forward, and around 60% of heat energy is dissipated as waste heat. So for every 13% of waste heat being recovered, it is supposed that the mileage per gallon will be doubled? I think it works and obviously is much better than gasoline direct injection.-- John1973, Dec 29 2005 Yes, this idea would allow for a more complete burn, but no, I don't think it would be beneficial at all. A gasoline engine needs, if anything, to retard the burning of the fuel untill the crankshaft is closer to 90 deg instead of TDC to promote more rotational energy instead of wasting it by forcing the conectind rod directly into the main bearings. But on a conventional engine, there is not enough cylinder pressure left halfway through the stoke to be of much use. And I could be wrong (it wouldn't be the first time and probly won't be the last), but my understanding is that a gasoline engine does not run on explosions, but on controlled burn. Sudden spikes in pressure that result from an explosion can kill an engine quickly, but controlled complete burn, maximized at the right time to give maximun turn on the crankshaft, is the end goal. Think of it this way: What if you were trying to operage a piston engine by hand. You only have a certain amount of energy to use for eacj stroke, because, let's face it, you're getting old, and you can't quite keep up like you used to. This represents the limited energy per unit of fuel. So which method would be the most effective? Pressing on the piston with a rubber rod as it is halfway down the stroke (90 deg BTDC) where the more continuous force is acting farther out on the crankshaft, increasing the moment (F*D), or banging on the top of the piston with a sledge hammer just as it passes TDC?-- Hunter79764, Feb 18 2007 [Hunter], your logic makes sense, but a diesel engine sounds very similar to this engine (the fuel combusts exactly when it is injected) and most diesel engines certainly have no problem with durability. Of course part of that is due to the fact that the engine components in a diesel are so much heavier and beefier than those in a gasoline, but they still do run a lot like you described with the sledgehammer: sudden combustion as soon as the fuel is injected.-- acurafan07, Feb 18 2007 But diesels aren't sudden combustion. It is a controlled burn as the fuel is injected, and the injection starts when it will do the most good. And diesels are built much beefier, which is why they often don't rev very high or get there fast, making them great for some applications (namely large trucks) but poor in others (ever see a diesel Ferrari or 'Vette?). I don't think [Vernon] intended to re-create the diesel engine, but it looks to be a gasoline version that has none of the benefits of either gasoline or diesel with all of the drawbacks.-- Hunter79764, Feb 18 2007 Oh I get it now,the diesel can be injected as ultra high pressure while the boiled gasoline would be a gas and couldn't be injected at very high pressure (otherwise it would condense). To ever get the gasoline to a high enough temperature that would prevent it from condensing at high presure would require a lot of heat and would most likely be very, very dangerous in an accident or if a fuel line broke.-- acurafan07, Feb 18 2007 Heating fuel is easy, just extend the gas supply line to the top radeater hose and wrap it around the hose several times, then insulate it. When the hot gas is injected into the hot cylinder it will vaperize better. Your cars control system will adjust to a leaner mixture to a point. It has a range of control. The people in england are using heater plugs to heat vegey oil, I bought one and have been playing around with it on the bench. Its a big energey consumer and its tip is exposed to the fuel. It's ok as long as the fuel is moving. The heat transfer is not what I expected. Another way to increas the vapor is to add acetone to the fuel. I have just started to do this and the indications are good. I am alreading seeing good results. I added one ounce to 10 gallons of gas. Have any of you tried these ideas yet?-- moogey, Jun 12 2007 I was hoping to get this near the top as analysis of vernon's ideas, and to face some of the confusion expressed near the end of the conversation. I will inevitably express my own observations as well.
First, this system depends on any grade or type of evaporateable fuel to be compressed until released into the combustion chamber. There, not an explosion, but an even, complete burn is sparked by multiple sparkplugs, instead of a single time consuming, one-end-to-the-other ignition.
The heated and pressurized fuel is released by injection. The injection jets have to be engineered to withstand the backblast of combustion. (And notice this is a 'combustion' engine, rather than 'explosion').
It would essentially look like a regular fuel injection assembly.
Think of the geyser, Old Faithful. The Water is super heated and pressured underground, until a load of superheated water vapor explosively escapes, carrying the scalding water into the air.
In my understanding, this form of engine would have two miniature 'Old Faithfuls' pointed in eachother's general direction, lit on fire. This also reduces timing since both release for half the duration a single release would take.
And the best part, all this can be done in a small package.
Needed :: Air pressure (for ramming air), Fuel pump, Electronical Controlled Heater/Fuel Locking Injection Assembly. Sparkplugs electric system. (Brain for controlling it all under varying conditions.)
The Assembly would handle heating the fuel, releasing it underpressure, boosted by air, into the combustion chamber, via a small one-way port. Not much fuel pressure is need until it is ready to enter the heating chamber, where it would be released under its own pressure into a rush of air. The small distance between release and cumbustion would not affect the vapor created by the mix, though back pressure onto the air and fuel release mechanism need to be considered.
Timing has to be considered here. Fuel pressurization (due to increased tempurature) takes some finite time, with the cooling from introduced fuel. Heating times controll tempurature and tempurature range of the heating element. (Heating has to be internal to the Assembly). Coordination of air and fuel release. Fuel release during air flow. Inevitably, the flow of fuel will be rapid, and need intense heating to reach the desired pressurized state. The process of heating and release happens in parts of seconds.
When the fuel releases from the heating chamber, there is a pressure deficit for the fresh fuel to fill through a one way valve. Great pressure is needed to enter the heating chamber; equal to the amount of pressurized fuel released for cumbustion. The area for heating doesn't need to be large, just an appropriate resevouir. A valve fore, and aft. Initial system pressure helps prevent reverse flow even when heated.
The air is delivered to the combustion chamber two ways, for two reasons.
One, through the Injection Assembly, to deliver particalized fuel. The amount of pressure created by heating is likely not enough to scatter the fuel consistently through the chamber for combustion, even with the increased expansion capacity.
Two, through air intake ports in the piston chamber, because getting enough air for uniform fuel ignition into the chamber through the above, would be impossible.
One observance I have is that the process for exiting the heating section is evaportion, I guess partly driven by fuel wanting to enter, if it happens at the same time, another issue with timing.
Another observance is this kind of setup would need to start cold, therefore have rapid heating capabilities, hence a small heating section and high grade heating equipment. That is, heat fuel to the proper level right when you put in your key and turn over the engine. Small may work best, or the brain could adjust flow pressure and air pressure to compensate for cold fuel.
In all, this system consists of numerous injectors, sparkplugs, centrally pressurized air and fuel, and an appropriate electrical system.
Conceivably, a pressurized gas like propane could be utilized with high efficiency.
Vernon, thanks for the discussion.-- toltecorion, Feb 04 2008 [toltecorion], you're welcome!-- Vernon, Feb 04 2008 I think with all that fancy talk and crooked ideas, one major idea got lost in the translation:
It would look almost exactly like contemporary engines that use fuel injection.
Has anyone seen any media on the guy who uses electrolized water as a blowtorch? He was converting a vehicle to run on the same concept. The blowtorch was HOT.-- toltecorion, Feb 07 2008 It looked hot, but was mostly bogus video. The electrolyzed-water gas takes more energy to make than you get out of it--it doesn't make sense as car fuel.-- baconbrain, Feb 07 2008 This idea of “Boiling” gasoline is unique. Yet, if it stands alone to contend with the rest of the technologies, it would eventually suffer from its own major flaws:
1. The boiler is bulky and contributes to enlargement of the holding tank of the high pressure vapor. 2. The boiler should have much higher temperature to ensure that the fuel leaving the injector nozzle is still in vapor state even though subjected to high pressure. 3. The highly pressurized holding tank should be rigid enough to prevent explosion due to rupture caused by material fatigue from tensile and thermal stresses. 4. A fuel pump (or fuel injector) is needed to transport fuel from the normal tank to the pressure tank. 5. The multiple fuel injectors in the cylinder entail complex fuel metering system. 6. The issuing flame front delay the oxidation of the trailing injected vapors. 7. Formation of NOx would eventually increase due to higher temperature near the flame front wherein both adjacent N and O molecules are closer to each other and readily absorb the heat.
Therefore this could not compete with existing fuel introduction technologies.
One unique solution is to integrate this idea to old diesel “air injection” technology, THUS, TRANSFORMING THIS INTO THE FUEL INTRODUCTION EMPLOYED BY MY ROTARY ENGINE.
As your idea eliminates carburetor and its entailed disadvantages, this integration I proposes (or the overall technology I employed in my rotary engine) would eliminate all of your major flaws and introduce additional major advantages, provided that the ordinary gasoline engine is replaced by a multi-fuel engine. So, here it is.
Ordinary air-injector principle first employed by Rudolf Diesel needs a separate compressor, and so is your idea too (as it uses high-pressure fuel pump). But a separate compressor is not needed for a multi-cylinder engine; just employ half the number of cylinders as air compressors, the other half as expanders. Your boiler is substituted by the heat of compression. Your pressurized tank is substituted by very compact transfer ports on each cylinder pairs. The fuel is introduced in this manner:
Fuel is introduced and calibrated to the transfer-port holding cavity which is also the passageway of the compressed air. The very hot highly-compressed air is introduced to the transfer port at TDC by opening a needle valve. Some compressed air then pushes the obstructing fuel to the expansion cylinder and the rest of compressed air bypass and mixes turbulently with the injected fuel to the expansion cylinder in a swirling motion. The fuel is instantaneously atomized and rapidly heated resulting in a more thorough combustion. NOx formation is minimized due to the swirling motion that ensures some combustion gas reintroduction to the flame front to absorb the tremendous heat that may trigger NOx reactions.
While this proposed fuel introduction technology may not significantly improve ordinary reciprocating engines due to considerable distance between cylinders, this is perfect for my rotary engine where chambers are much closer. See link of my rotary engine for further info.-- rotary, May 21 2008 [rotary], your notion of injecting air has a rather large flaw, called "stoichiometric ratio". That is, when you want Substance A and Substance B to COMPLETELY react chemically, then you want exactly the right amounts of each substance. Two parts hydrogen plus one part oxygen is needed to make water, for example, so the stoichiometric ratio for that is 2:1.
Are you not aware that the amount of air needed to react with liquid fuel is a VASTLY greater volumetric quantity? Not to mention that since air is only 1/5 oxygen, you need 5 times as much air to get the right amount of oxygen to combine with a specified amount of liquid fuel. Thus, injecting air is downright silly, when the goal is to react as completely as possible the fuel and the air.
In the main text of this Idea, the notion of boiling the fuel helps reduce the amount of fuel that actually gets injected. This helps ensure that all the fuel can react with the oxygen in the compressed air in the combustion chamber. While you have made valid points about how structurally solid this Idea needs to be to work, not everything needs to be exactly as either I or you have described, to implement my Idea. For example, what if the fuel injectors were also the boilers? Then only they need to have superior structural solidity; the rest of the fuel handling system can be pretty ordinary.-- Vernon, May 21 2008 [Vernon], what made you think that air-injection principle for fuel introduction tends to violate stoichiometric ratio? Maybe you misinterpret it and haven’t read the history of Diesel engine technology regarding that long-forgotten method of fuel delivery to the combustion chamber. For me it is aptly termed high-pressure-air-assist fuel injection. It is a pneumatic force that squeezes out the obstructing fuel off the injector nozzle, provided that its pressure is much greater than that of the power chamber before combustion. Take note too that in my previous anno I mentioned of the bypass air in my modified system so that the right stoichiometric ratio is maintained at the swirling combustion right at the front of the injector nozzles.-- rotary, May 24 2008 [rotary] wrote: "air-injection principle for fuel introduction"
--That's self-inconsistent. If you are injecting air, you are NOT injecting fuel. And vice-versa. Which I why I wrote what I wrote in my last post. The whole purpose of a Diesel is to compress a lot of air to a high degree. You don't need to inject air into that! You do need to inject fuel. Now, if a Diesel was modified to compress fuel, then a rather stupendous amount of air would have to be injected, to achieve a stoichiometric ratio. :)-- Vernon, May 24 2008 [Vernon], air injectors preceded mechanical injectors and the modern common-rail injectors. As you noticed in mechanical injectors, the fuel is metered by rack-and-pinion mechanism (with fuel port and helical slot varying the effective stroke) then injected through the radial nozzle array by cam and plunger components. In air injectors, a highly pressurized air was bled out from its tank by needle valves to force the metered fuel through its nozzles; it has the same effect with cam-and-plunger assembly. You really misunderstood those mentioned processes—just to deliver the metered fuel, air injectors does inject air and mechanical injectors inject liquid fuel only.
In my previous anno, I suggested a cylinder dedicated for intake and compression only. I took notice of your idea of boiling the liquid fuel, so the simplest and most effective way to do it is to use the heat of compression. With this method, you don’t necessarily need a boiler and a special tank and a special device to force fuel to the combustion chamber. (Or, maybe, you just like to complicate things! Hmmmm…)-- rotary, May 24 2008 [rotary] wrote: "just to deliver the metered fuel, air injectors does inject air" ============ Then that's NOT energy- efficient. The reason is, if some of a tank of pre-compressed air is able push fuel without combusting with it, then it must be cool compressed air. And if this cool compressed air gets into the combustion chamber with the fuel and the hot air that was compressed by the piston, then it cools that air by mixing with it. But we want HOT air, to combust with the fuel, in a Diesel!-- Vernon, May 25 2008 Oh, [Vernon], at least now you somehow know how the air injector employed by Rudolf Diesel operated…
Please read; my previous anno was not adopting that old technology without suggesting a major modification. // But a separate compressor is not needed for a multi-cylinder engine; just employ half the number of cylinders as air compressors, the other half as expanders. Your boiler is substituted by the heat of compression. Your pressurized tank is substituted by very compact transfer ports on each cylinder pairs. // // Fuel is introduced and calibrated to the transfer-port holding cavity which is also the passageway of the compressed air. The very hot highly-compressed air is introduced to the transfer port at TDC by opening a needle valve. Some compressed air then pushes the obstructing fuel to the expansion cylinder and other bypass and mixes turbulently with the injected fuel to the expansion cylinder in a swirling motion. The fuel is instantaneously atomized and rapidly heated resulting in a more thorough combustion. // (This method even drastically lower NOx while yours just do the opposite.)-- rotary, May 25 2008 [rotary], you still aren't making sense. First, if you use heat of compression to heat the fuel, then you are simultaneously cooling the air that was compressed. Second, if you mix hot compressed air with fuel, ignition will happen inside the injector, and not inside the cylinder. Third, if you plan on using extra cylinders only for compressing air, then when that air is cooled to heat the fuel, its pressure will go down, and there will not be more pressure than inside the cylinder you want to inject the fuel.
Half-baked as it is, my boiler has NONE of those problems.-- Vernon, May 25 2008 Well, [Vernon], although your comprehension of my half-baked idea is still half-baked, at least some of the mechanics is clear to you.
// there will not be more pressure than inside the cylinder you want to inject the fuel // this is not clear whether you are referring to the intake-compression cylinder or the expander.
Anyways, I hope you are considering the heat of compression as viable heater of the fuel before it is injected. I believe it is not clear to you how can a liquid fuel be boiled by the heat of compression that is in the adiabatically compressed air. But first, I have to clarify things that are misconceived:
First, I never intended to have a lower compression ratio to fail ignition. Imagine, at 30 compression ratio at the start of injection with 15 degree C initial temperature would already yield 850 degree C final temperature; no matter how the fuel readily absorb the heat, the average temperature is still conducive to ignition. The compression chamber piston could still inject air up to the squish clearance of < 1 mm which consequently achieve compression ratio > 50. Second, I never intended to vigorously mix the hot compressed air with the fuel inside the injector. Imagine a long cylindrical tube of fuel: a very small circular area of it exposed to the impinging compressed air is open for combustion with the resulting combustion product serve as barrier to further combustion. That relatively small combustion would deliver an initiating kick to the fuel to exit through tight nozzles. Third, the bypass hot compressed air with much lesser viscosity would heat up the casing of the fuel and exit through a tighter nozzles adjacent to the fuel nozzles, to maintain a leaner mixture for combustion and conform to right stoichiometric ratio for complete combustion.
Let me explain the overall process. The intake and compression cylinder (or compressor) would deliver hot, highly compressed air to the expansion and exhaust cylinder (or expander). As the transfer-port needle valve is opened, the metered fuel inside the injector shaft is subjected to intense pressure. The main air transfer duct has air bypass serpentine ducts surrounding it that exit through circular array of nozzles much closer to the fuel nozzles. The cranks of the two cylinders are out of step by few degrees such that BTDC of the compressor at probably 30 compression ratio the expander is at TDC. Fuel and air injection continues BTDC of compressor and ATDC of the expander until TDC of the compressor wherein the fuel is finally emptied past the injector. When the transfer port and the nozzle valve are finally closed, another metered fuel would be introduced to the emptied duct ready for the next injection process.
One great advantage is having a very short flame vortex with thorough and instantaneous combustion as the injected fuel and air are in uniflow. There are numerous other advantages too long to mention. (Will you intend this to be fully baked?)-- rotary, May 26 2008 [rotary], What I wrote about pressure not being enough was based on the assumption that two cylinders compress air, and air from one is to be transferred to the other, with fuel being added along the way. I am exactly correct in saying that if you use the heat of the compressed air to heat the fuel, the pressure will drop in the compressed air. Look up the Gas Law if you don't believe me. Thus there would not be sufficient pressure to overcome the pressure in the destination cylinder! (There wouldn't be even if no heat was transferred, since both cylinders have the same pressure in them!)
However, the extra details you presented indicates that you seem to be dividing the 4-stroke cycle into two cylinders. One intakes air and compresses it, the other experiences the power stroke and exhausts the waste. This means the when the compression cylinder and the exhaust cylinder are near top dead center, you open a transfer valve and also let fuel enter the stream. But this will still suffer from combustion inside the injector. The total energy, normally sufficient for a Diesel to ignite injected fuel, remains the same, regardless of whether some has been transferred from the compressed air to the fuel in your scheme.-- Vernon, May 26 2008 Vernon: // …also let fuel enter the stream. But this will still suffer from combustion inside the injector. //
Well, I never wrote, suggest nor intend to let fuel enter the stream inside the injector. Before the transfer valve is opened, the liquid fuel is already in the cylindrical duct in full contact to the spring-loaded injector pin valve of the fuel nozzles. A sudden pneumatic force upstream, brought by opening the transfer-port needle valve to allow the hot pressurized air to pass, would retract the spring-loaded injector pin valve from its seat and force the fuel to enter a heated passageway leading to its nozzles. The fuel chamber has either fins or air jackets that are heated by the bypass air (or the fins/honeycombs act as heat regenerator/storage). The bypass air has its own nozzles in close proximity to the fuel nozzles. Although insignificant, the rushing bypass air just after the nozzles would have a venturi effect to the nearby fuel sprays to further atomize any expanding minuscule droplets.
Ceramic liners insulate the heat of the transfer manifold. Some combustion gas can be recirculated and introduced into the injector to provide additional heat to be stored in its heat regenerator and would also provide a buffer zone to prevent reactive contact of the fuel and the impinging hot, compressed air when the transfer valve is opened.
One advantage is that the fuel is introduced inside the duct or holding chamber inside the injector with relatively little pressure because the chamber at that moment is isolated from the compressor and expander. Also, the detrimental detonation possible with normal gasoline engines is precluded.-- rotary, May 27 2008 [rotary], sorry, but all your fancy words don't prevent heated air and fuel from combusting before they enter the expansion cylinder. In one sense you have to have it that way, if there is no pressurized air already in the expansion cylinder to cause fuel to ignite. Think about it.-- Vernon, May 28 2008 Vernon! Think about the signal-to-noise ratio!-- afinehowdoyoudo, May 28 2008 This is the fifth idea down when I [google]: degree of atomization gasoline.-- daseva, Dec 15 2008 fuel atomization isn't really the goal. clean and efficient burn s the thing.-- WcW, Dec 15 2008 Sorry if I haven't followed up on this wonderful topic, considering this technology is ripe to remedy the looming crisis of petroleum's limited supply.
The expander (expansion cylinder) should already have a compressed air of much lesser compression ratio, say 1:4, brought about by scavenging late at the exhaust stroke. (Late scavenging is relatively easy as there is already momentum of the exiting combustion gas and the scavenging air is supplied by the residual compressed air left by previous compression stroke of the compressor.) Yet, when the exhaust gas are totally expelled, the fresh scavenging air left in the expander is trapped by early closing of exhaust valve BTDC.
So, there is pressurized air already in the expansion cylinder to cause fuel to ignite - just enough to clarify the issue pertaining to Vernon's last concerns.-- rotary, Dec 15 2008 [WcW], how do you expect to burn the fuel if oxygen can't get at it, because it is in the middle of a droplet that has partly burned and now is surrounded by waste products of that partial combustion? Reducing droplet size to near-zero automatically ensures that this cannot be a problem.
[rotary], the "air" you talk about as being present looks to me to be left-over waste from the previous combustion cycle. HOW is it going to ignite new fuel, if its oxygen has already been used up in the last cycle?-- Vernon, Dec 15 2008 Oh, another careless misconception, hmmmm. When the anno says scavenging, it never means exhaust gas recirculation, dear Vernon, but fresh air introduction, although this air is very minimal and the operation occurs very late in the exhaust stroke. The leftover pressurized air I am referring to is the remaining compressed air left between the compressor piston and main transfer valve trapped in the squish clearance and cavities. The flow is from the compressor (or intake-compression cylinder) to the expander (or power-exhaust cylinder) with the use of pin valve in the compressor side, and poppet valve in the expander side, with the manifold in between acting as holding tank. The pin valve is an auxiliary transfer valve timed at exactly TDC of the compressor when the main transfer valve has finally done its main objective. It is meant to capture the pressurized residual air that is normally wasted on the return stroke, thus enhancing volumetric efficiency of the compressor.
This minimal air is primarily to effectively combust the initial fuel spray, although there is ample bypass air provided by the main transfer valve. It is possible to retain some residual combustion gas in the mix just to effectively employ exhaust gas recirculation mitigating (or eliminating) NOx formation at the early stage of combustion.
BTW, that leftover compressed air trapped in the squish volume and gaps seems very small, but don’t be fooled. It is an ample air considering that the compressor operates at more than 30:1 ratio and the final pressure at TDC of compressor is fairly still above 15:1, depending on the restriction imparted by the air injector.-- rotary, Dec 15 2008 [rotary], ok.-- Vernon, Dec 16 2008 all for it but note that the boiling points given in the first anno are for normal atmospheric pressure, whereas at injection we'd be looking at 30-40 atm in the cylinder and more in the injector. Is the temperature obtained able to support this ? Even if not, you'd still be closer to evapouration than when you started.-- FlyingToaster, Aug 31 2009 Almost baked -- see my link-- cowtamer, Mar 09 2010 [cowtamer], I hate to say this, but the link you posted today is for a web page that contains the link that I posted today. In other words, I posted a lower "degree of separation" link, from the original source, than you did.-- Vernon, Mar 09 2010 BMW (and others) have offered direct injection gasoline engines for years. This is just another "me to" investment black hole with no industry backing. To the technical eye the use of mechanical Bosch style direct injection with an engine driven pump screams "1976" not "The Future of Cars".-- WcW, Mar 09 2010 [WcW], you haven't been paying attention. None of those direct-injection technologies involve spraying hot GASEOUS gasoline into the engine, they all involve spraying small droplets of liquid gasoline.-- Vernon, Mar 09 2010 in the timescale of an ICE there is plenty of time for a tincy droplet to become an evenly dispersed vapor, especially in the turbulent action of the compression stroke. If the problem was one of "droplets" being "injected" than the "carburetor" which produces few if any droplets under constant load solved it a long time ago. Fact is that the BMW system injects at such a high pressure that the only droplets that are present durring combustion reformed by compression a phenomenon that this whole discussion has carefully skirted around. As long as the charge is efficiently combusted shortly after the ignition event with a generally soiciometric distribution of the mixture the method with witch the fuel was introduced is of little importance. To illustrate this consider the example of liquid injection propane engines and gas mixing propane engines. The gas mixing propane engine achieves a very uniform distribution of charge but the liquid injection engine with its clearly less evenly distributed charge is considered a superior engine due to the fact that it is more thermodynamically efficient and can be designed to operate over a wider window of mixtures. Droplet injection and other forms of "crude" fuel introduction allow the engineer to "shape" or "place" the mixture/charge in the chamber in such a way as to take advantage of quench/compression and other combustion phenomena to maximize efficiency and output. This is the notion behind sequential injection and direct injection, to take control of the combustion even using timing and mixture placement rather than evenly combusting a uniform mixture which isn't happening no-matter-what in a piston engine.-- WcW, Mar 09 2010 [WcW], what you wrote doesn't change the claim that these guys are getting 64 miles per gallon instead of 30-40, by injecting gaseous gasoline instead of liquid gasoline. It logically follows they are getting more complete combustion and thus more energy per unit of gasoline injected (and less polluting emissions, too). Which is exactly what this Idea has been about.-- Vernon, Mar 09 2010 You mean that their engine can drive down the road? Even you know that that is a bogus claim meant to drive speculative investments. Engines don't get MPG, vehicles do, and my onld CVCC got 50+ MPG on a stock engine with 145k on it. With good aero work and high mileage technique it would have easily gotten 60+ and that 2v 4cyl 1100cc engine had a 2bbl carb.-- WcW, Mar 09 2010 [WcW], I think I would wait for more data before jumping to such conclusions. Also see "superspray" link.-- Vernon, Mar 10 2010 Transonic (the company in the "Horse's Mouth" link) doesn't use gasoline in a gaseous state -- it uses gasoline in a supercritical fluid state.
There are several effects of this that obvious to me:
First, the one of which the company's web site mentioned -- the fuel has enough thermal energy to spontaneously combust when injected into air (even at the relatively low compression ratios that gasoline engines use). Because it is the fuel's thermal energy, not the heat of the compressed air, that initiates combustion, such an engine is not a Diesel (compression-ignition) engine... it probably belongs in some new category.
Second, just like any other supercritical fluid, the fuel has no surface tension, allowing it to mix with air extraordinarily quickly, vastly faster than if it were a liquid.
Third, because the fuel in Transonic's engine is *not* a gas, it's density is much higher that it would be if it were a gas... allowing a much larger mass of fuel to be injected in a small amount of time, given the size of the fuel injector. A gaseous gasoline direct injected engine would require many injectors, or larger injectors, or injection for a much longer time, or a combination thereof.-- goldbb, Mar 10 2010 [goldbb], a supercritical fluid can be very much like the highly compressed gas that I described in this Idea ("fluid" does not automatically always mean "liquid").
Note that if the normal ratio of water volume to steam volume is 1:1600 (take some quantity of water and boil it and then measure its volume), then if you take that steam and compress it 1600 times you will have the same density of fluid you started with, but it won't necessarily be liquid! (Also note, the average volume ratio for most liquids-to-gases is about 1:1000.)
I fully understood that fact. I ALSO knew that there are two significant problems with "just boil gasoline and use the vapor" --First, if you used an old-fashioned carburetor the hot fuel mixing with air might spontaneously ignite even before reaching the engine, and Second, if a slightly modified ordinary fuel injector is used, there would not be enough sheer quantity of fuel to run a highish-horsepower engine. Compression of the gaseous fuel is required to increase the quantity of gaseous fuel that enters the engine.
Sure, the Idea means that you should not need to inject quite as much as when injecting ordinary liquid fuel (thanks to more efficient combustion), but you still need to compensate for that (typical) 1:1000 ratio of volume. That is, X cubic millimeters of uncompressed gaseous fuel is about 1/1000 the quantity of X cubic millimeters of liquid fuel. The increase in fuel-usage efficiency is not hardly going to go up 1000 times!!! --and therefore the gaseous fuel MUST be compressed.
And that's why this Idea is basically the same as what the Transonic Combustion people are talking about. They are just using the fancier word, "supercritical".-- Vernon, Mar 10 2010 BAH, if they had a real working engine we wouldn't be looking at a computer animation and they wouldn't still be fishing for investors. This isn't so complicated to construct that you need to hem and haw about it for decades. How many "trust me it really,really works" new engine designs does it take to learn that a working idea gets industry and institutional backing, wins awards and gets built (like the BMW direct injection system which IMHO this is a copy of) without a long process of public "persuasion" that invites people to "believe" in it.-- WcW, Mar 10 2010 [WcW], simple or not, it still takes money. I've never had enough money to consider trying to build this Idea into hardware; that's why I posted it (among others).-- Vernon, Mar 10 2010 "supercritical" is a pretty specific term; "transonic" on the other hand sounds like something akin to those mist generators.-- FlyingToaster, Mar 10 2010 <link>-- 8th of 7, Mar 10 2010 WcW, although I can't seem to find it on Transonic's own web site, various articles about the company indicate that transonic has in fact built a working test engine.-- goldbb, Mar 10 2010 Jolly good.
There's a university lab somewhere that's built a Stirling engine using Hydrogen as the working fluid. That doesn't mean that you're going to be able to buy a car with a Stirling powerplant any time soon ...-- 8th of 7, Mar 11 2010 I don't see how they go from 30 to 64 mpg with the only change being the injection system.-- FlyingToaster, Mar 11 2010 Sounds like a vapor carburetor idea.-- travbm, Oct 29 2015 direct injection - you don't have to worry about the carburetor blowing up.-- FlyingToaster, Oct 29 2015 //I don't see how they go from 30 to 64 mpg with the only change being the injection system.//
It's probably all done in software.-- MaxwellBuchanan, Oct 29 2015 random, halfbakery