h a l f b a k e r yStrap *this* to the back of your cat.
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Nitroglycerine ("soup") is the ultimate fuel. It has the fuel and oxidant built in. So using it, we can make a totally sealed internal combustion engine, one which does not take in air or spew out exhaust.
But most of all, constructing and running a few millions of these engines will give us the
necessary experience to handle the enormous energy density of helium inside fusion powered cars.
Stoichiometry
http://dbhs.wvusd.k...-Stoichiometry.html
For the unenlightened. [8th of 7, Sep 17 2002, last modified Oct 21 2004]
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Take me to the Nitro-engine demolition derby! I'll take tickets in the nose bleed section though... |
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Howz't gonna stress out security when everyone starts carrying thermos bottles into work? |
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how do you figure the no exhaust part? |
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There'd be plenty of exhaust. Nitrogen, mostly (I *think*). Quarterbaker will know. |
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There'd be plenty of intake too. Not *air* intake, but *fuel* intake. You definitely don't want your entire trip's fuel in the cumbustion chamber when you start your engine. And you won't want your spent fuel lingering around in there, either. |
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Explosive reactions are inherently ill-suited for piston-based engines. Not only do they cause extreme stress in the engine materials (and eventual fatigue failure) but they also lose much of their energy through high-pressure shock waves in the engine block. Fuels with higher octane ratings perform better because they burn more slowly. Less energy is lost to shock waves, and more is directed at pushing the piston smoothly through its stroke. Diesel fuel is more efficient still in part because it is heavier and burns even more slowly. |
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bristolz - yes, there must be exhaust. See, the pressure created by the explosion must push a piston or perform some other work in order to transfer into mechanical energy. After that, the pressure must be released somewhere (you can't keep compressing indefinitely without a release), otherwise the piston won't be able to return to its start position for the next cycle. I'm not chemist enough to know what the products of nitroglycerine are - but, yes, nitrogen would be a big component.
And BB is completely correct: much of the energy of an explosive event is lost to phenomena that can't be translated into work. Well, some of them can -- for example, there's a nifty new device that can convert noise into rotary power. But basically all of BB's objections are spot-on. The best use of any fuel source is to burn it as slowly and completely as possible.
Even if it were possible to have an explosive-based power source for locomotion, nitroglycerine would be a poor choice. It is far too sensitive (unstable) for consumer handling. |
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If the exhaust gas were Nitrous Oxide, you could just vent it anywhere for a quick laugh... |
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Part of the power could be used to compress the exhaust and store it for delivery to a central waste processing facility. |
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We will have to find ways of harnessing explosive fuels. Fusion reaction is supposed to take place by bombarding deuterium pellets with neutrons and laser beams and pressure waves, and the resulting explosion is harnessed to do useful work. |
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Handling the explosive fuel and its exhaust in a closed loop will mimic the processes necessary to deal with fusion powered cars. |
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We are doing it for the experience, to pave the way for fusion powered cars. |
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So this idea + annotations = dangerously explosive car, which you drive around at super-fast speeds, insanly laughing your head off? I'll vote for that. |
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why do you need fusion powered cars? why not fusion power stations and electric cars? |
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We are already using a fusion powered reactor to power our gadgets. Only thing is, it is way too far away from us (the Sun). |
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Step two will be a large fusion powered reactor on earth producing electric power. |
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Then we get good at running it and we scale it down and run cars with it. |
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And then before you know, your toddler kid is playing with his fusion powered transformer toy. |
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Imagine a leak in a hydrogen-fusion powered car. Oh, the humanity. |
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We've looked at the stoicihometry of this and it's not as daft as it first seems. You could design and build a tiny "airless" fuel-injected two stroke using a fuel with the same thermodynamic properties as NG. |
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The man problem is the handling characteristics of the fuel. NG is chronically and dangerously unstable (now, where have we heard that phrase before ?). You can't pump it or pressurise it, and it's highly sensetive to shock and friction. There's no way a material with those properties could ever be considerded as a fuel in a passenger vehicle. |
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The other problem is energy density. Explosives like NG in fact exhibit poor energy density compared to most fuels, as a high proportion of their mass is oxygen. Burning a kilo of coal or gasoline, using an external oxidant source (air) releases far more energy - albeit more slowly - than the anaerobic reformation of NG into "combustion" products. You won't get many M.P.G. |
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But you could build a VERY interesting dragster ..... |
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What the hell is "stoichometry?" |
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Exothermic reactions which contain correct proportions of oxidiser and fuel are said to be "stoic". They tend to proceed with the greatest rapidity, efficiency and violence. Stoicihometry is the study and calculation of the relevant proportions. See link. |
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Ah, so it's the art of calculating atomic weights. |
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Not entirely, but atomic masses come into it. See link. |
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What happens if you use microscopic nitroglycerin "cells"? |
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Just a thought about fusion, theres that little problem of strong nuclear forces releasing dangerous gama radiation, and X-rays. Perhaps we should leave fusion to the sun, since it just seems a little safer far below all that hydeogen. |
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Let's build the car out of magnesium, since it also provides it's own oxygen for combustion. After trying to navigate your first speed-bump, we won't have to clean up the debris or dispose of any unsightly remains.
Perhaps the nitrous oxide released into the immediate vicinity of the scene will be sufficient to let onlookers laugh instead of cry? |
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I had an idea similar to this but was going to suggest C4, (plastique explosive), much more stable and could be easily insulated against static electricity. |
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Guess I'll have to cross this off the list of future postings. (+) |
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I'm a mechanic and let me tell you to actually handle the kind of pressure this thing would produce the engine would have to be built at least 10 times stronger than a diesel wich would make a lets say 2.0 L engine weigh maybe 2500 lbs or more not to mention i sure wont work around ng who ever came up with this idea is a looney They got to much time on thier hands. |
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Nitroglycerine detonates rather than deflagrates. The difference is in deflagration the flame front spreads through the mixture by heating neighbouring molecules and thus igniting them. Nice and slow and controlled, and it takes time for the entire cylinder fill to mix. In detonation a shockwave forms that instantly ignites the fuel as it travels and burns the whole lot in miliseconds.
If you could, of course, stop the nitroglycerine from burning so rapidly it detonates then yes you would have a convient all-in-one fuel that doesn't need air.
Although it would make more sense to store a fuel and oxidiser seperately for safety reasons!
Nitromethane is a fuel that is 40% oxygen by weight yet has good detonation resistance. But you still need a oxygen source. Some dragsters use nitrometh, methanol and nitrous oxide with only a little bit of air
Also to commet on fusion: Even in the most extreme fuison reactor conceiveable the plasma would still be many times below atmospheric pressure and the reactor chambers are really near-vacuums. There is such little actual plasma that in current research reactors if the plasma gets out of containment it can't harm the reactor walls, barely even singes them. |
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//Part of the power could be used to compress the exhaust // [neelandan] All of the power of an engine comes from the gas expanding (that's what pushes your pistons). Using power to compress the gas back, even if this process was 100% efficient (which it's not even close to) would net you no extra power for driving. |
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Just look up "Carnot cycle". |
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As venomMX says, fusion isn't really an explosion. There is no enormous volume of gas produced, just lots of heat and light. The heats boils water which drives a steam turbine. |
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I've always wondered how the scientists planned on getting water close enough to the fusion reaction that it will heat up, but far enough away that the pipes won't melt - is seems that the ideal location (given the plasma physics inside a tokamak) is roughly inside the wall of the containment vessel. This could require the wall to be either (A) very heat resistant or (b) opened up in a section to let the water in. You can't really have an open vacuum, although Tesla did develop something like it (a vacuum chamber that has a hole in it, used to fire frictionless projectiles). |
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The points have been made in the annotations that explosions lose much of their energy to shockwaves and that they cuase extreme stress to they engine components. How about designing the engine components to minimize this shockwave effect. The lifters/rods/cams are just a complicated mass-spring device that we have all seen in first year physics. Just bust out some Graduate level numerical analysis and design a shockwave minimizing system. Additionally, to reduce stress just use smaller explosions and more cylinders. Like maybe a 24 cylinder massively damped 5 liter engine? |
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The usual stabilizer is Kieselguhr, The skeletons of many many diatoms. (Little armored plants. Quite neat really) It's kinda claylike. |
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Instead of using this fuel to power a car. Why not reconsider using it as a fuel source for an stationary electrical power plant. Thus elimateing the obvious dangers of mobile volatile fuel. With the proper design considerations taken into account. Such a generator could be constructed to handle the extremely volatile mix. Including its shockwave output. I propose that instead of using the 18th century technology of Piston based engines to harness this energy source. Use a far more simplex energy transferance method. Construct structuraly reinforced tubes verticaly underground ( for safety concerns ) That have a protective lining (EM transparent, yet structurely strong enough to reflect the shockwave ) behind said lining would be field coils. Located at the bottom of the shaft would be an injector/detonator assembly. And in the center of the shaft would be a computer designed projetile (exterior lined with permanent magnet) which base is designed to 'ride' the shock wave produced from the Nitroglycerine detonation. Thus upon detonation, the projectile is propelled verticaly within the shaft to its apex. (Its apex to be determined in the preliminary testing stages and computer modeling. After which shaft to be 2 times the projected apex for safety concerns) Thus producing electricity (via the magnets passing by the field coils),both on the inital vertical accent. As well on its vertical decent via gravitational pull. Before the projectile strikes bottom another burst of fuel is detonated to continue the process. (Of course for safety concerns the lower field coils could be used as a retarder to protect the injector/detenator assembly in case of its failer )Refinements to materials used for stated generator would be continual to lengthen the projected life exspectancy of the the generator. |
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As someone who has worked with nitroglycerin, I can assure you the dangers are greatly exaggerated. Hollywood likes to portray it as a mysterious liquid that will explode if looked at improperly, but in reality you can drop a vial of the stuff off a building with no reprecussions other than broken glass. |
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But, like any sensetive material, the dangers increase with quantity and widespread use. It's only a matter of time before a little mistake becomes disasterous. Fortunately, there are plenty of materials in which it can be mixed for safe storage. Safer than gasoline even. |
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Nitroglycerin does not produce nitrous oxide, or any hazardous products. Interestingly enough, most explosives are far more environmentally friendly than hydrocarbons.
C3H5(NO3)3 -> 3CO2 + 2.5H2O + 1.5N2 + 0.25O2 |
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Nitroglycerin need not detonate. If the reaction is carefully undertaken, it will deflegrate, and can be used, in much the same way as gasoline. Buffers can be added to further inhibit detonation. |
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Even with safe storage, perfect stochiometrical reactions for nothing but minimal CO2 emissions, and cleanliness of use, it posseses the same fatal flaw as hydrogen combustion: it is not an energy source. The production of nitroglycerin burns more oil than gasoline automobiles would. Simple economics prevent this from ever happening. |
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[Macwarrior], the energy of a fusion plasma is released as the kinetic energy of charged particles, x-rays, and (sometimes) neutrons. The charged particles are trapped in the plasma---their energy helps keep it hot to sustain fusion. The x-rays and neutrons fly out and heat up the reactor walls. You put your heat exchanger fluid (H2O? He? Molten salts?) in pipes in the reactor walls. No need to bring *anything* in contact with the plasma. |
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Isn't nitroglycerine production pretty straightforward---nitric acid, sulfuric acid, and glycerine? Could the car have *separate* stores of non-explosive chemicals, and mix them together just in time to inject into the engine? |
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Not that a carload of H2SO4 is *such* a nice thing, but it sounds safer than a carload of nitroglycerine ... |
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Although the synthesis is straightforward, economic production of nitroglycerin is a bit more complex. The reaction is optimal at high temperatures, but this is extremely dangerous anywhere but a streamlined production plant. |
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In order to prevent a runaway nitration, casual production must be done under 25°C. This poses problems on hot days, especially since the synthesis evolves plenty of heat. |
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The reagents cannot simply be mixed in the deflegration chamber. The nitration of glycerol produces water which must be removed for a pure product. This is done by the sulfuric acid. |
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H2SO4 does not participate chemically in the synthesis, but rather absorbs the water. This gives you a caustic waste product that must also be removed from the final product. |
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Nitroglycerin can be stored safely by mixing it with nitrocellulose, forming a solid. It will still deflegrate into nonhazardous gasses, but the shock and friction sensetivity is greatly reduced. |
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Can someone give a professional opinion on whether or not this would be worse for the environment than burning petroleum? |
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Gasoline isn't just octane. It consists of a rather crude slurry of hydrocarbons, the stochiometry of which is never perfect. This results in fair amounts of CO and other noxious gasses from impurities. |
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Although nitroglycerin deflegrates cleaner than gasoline combusts, as I said earilier the production of nitroglycerin burns more oil than if it were burnt in engines directly. Nitroglycerin is not an energy source, only a storage form. |
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Wouldn't it be better to burn nitrocellulose in the engein instead? Significantly more stable. |
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Nitrocellulose doesn't perform nearly as well as nitroglycerin. It deflegrates slower, has a lower energy density, and releases carbon monoxide. |
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Depending on the ratio of NG to NC, the mixture has been used as everything from bullets to blasting geletin with great success. Blasting geletin has the same robust insensitivity as any other dynamite. |
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Of course, there are two added problems to using an explosive fuel. As it contains its own oxidizer, it is capable of exploding if the car were to catch fire. In contrast, gasoline will only explode when thoroughly mixed with air. |
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The second is the ease of sabotage. A simple blasting cap is all that is needed to detonate the entire fuel supply. |
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