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Originally Posted by RedDevil
Hmm. Pure oxygen, atmospheric pressure, iron and heat equals Thermal lance. |
Are you saying this scenario could potentially turn your engine into a thermal lance? What if we used ceramic, would that resolve that issue (take the iron out of that equation)?
Quote:
Originally Posted by RedDevil
It would allow lean burn without nitrous oxide, but the unused oxygen would be a risk for the engine. If you reduce the pressure to near-vacuum then it could work, but you'd have massive pumping loss.
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Lean burn means more efficient engine, right? How would oxygen end up being unused and how would it be a risk, explosion? How would pumping losses occur if the oxygen is DI? Obviously, there is an issue with exhaust still.
I wonder if water injection would be possible, with a condenser. How large of a storage tank would be needed to be able to store enough water to inject, "burn", exhaust, condense, repeat, without running out of water. Would the same amount of water need to be "injected" per cycle no matter what the speed of the engine is? In my mind, a system without water would be better, but how to do that without any associated risks. Would this system not work with a standard water/coolant and radiator system?
Quote:
Originally Posted by jamesqf
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I could just imagine NASA taking their rockets/shuttles to a local smog Check Only station!
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Originally Posted by sheepdog 44
It seems the problem is oxygen storage. As a scuba tank full of pure oxygen could only give a 10% increase in oxygen over the course of one gallon of gasoline. In the case of a prius, since it's fuel efficient you get more bang for your oxygen buck. You can get a 125% increase in oxygen for 16 miles, or a 150% increase for 8 miles. Which means if there were no oxygen in the atmosphere at all (only nitrogen), you'd have enough oxygen in your scuba tank to drive your car for just 4 miles!
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My idea is to not store the oxygen at all, but "produce" it on-demand.
Quote:
Originally Posted by sheepdog 44
You wouldn't need a super strong engine per se to keep it from melting. You'd just need to run your engine 5X as lean as it normally runs. But if your'e only compressing and expanding oxygen, then there might be issues as RedDevil says.
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So are you saying to run it at somewhere in the ballpark of 60:1? Wouldn't that also help make the engine more efficient? What else can you do besides compress and expand, are you referring to the intake and exhaust strokes?
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Originally Posted by RustyLugNut
The direct injection of pure oxygen and fuel/water means you do not need an intake valve. You could run the engine as a two stroke.
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The sub-idea of this scenario is definitely the use of direct injection. Much more efficient and if not, at the very least, more control. What would be the benefit of running it as a two stroke? Does the extra two strokes cause essentially a parasitic load on the engine, which is eliminated with two strokes?
Quote:
Originally Posted by RustyLugNut
Yes, under full load, you can inject your oxy/fuel/water to maximize temperature and pressure. But, you then have the option under light load to inject the minimum oxy/fuel/water and derive as much energy from it by over expansion. By using over expansion, it makes it easier to condense the water and reuse it.
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What is over expansion? A little research tells me that the piston arm is higher in the cylinder during the intake stroke and lower in the cylinder during the power stroke (which I assume means less oxy/fuel/water in the cylinder during the intake stroke and a larger turn of the drive shaft on the power stroke). Is that right? How does over expansion make it easier to condense the water?
Quote:
Originally Posted by RustyLugNut
RedDevil's idea of a small single piston engine is very doable. Originally, ceramic pistons, cylinders and heads were specified. However, using water as our expansion fluid means we can control peak temperatures. Ceramic coated parts would probably work. With no nitrogen present in the combustion chamber, we can run hotter than the 2300 degrees C temperature of formation for NOx to achieve higher theoretical efficiency while tempering maximum heat load via our water flow.
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If we have water in the equation, do we need a ceramic coating? How hot do you think we could go without causing issues (i.e. how much heat can the water take, along with standard cooling from the radiator)?
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How do we eliminate the issue of hydrolock, or is it not an issue in this?
I've already started a little diagram of what I am thinking and will get it up shortly.