[X-18]

Hello:

I've had this question for about a week, but I forget what cause me to have it. My question is, when someone runs NO₂ in there car, what are the reactions that happen, more or less.

When people use NO₂, they spray extra fuel into the engine because if the fuel were to have complete combustion it would melt the internals of the engine, this happens even if there isn't NO₂ in the mixture. Is the reason they need to use extra fuel because:

2NO₂ + heat --> 2NO + O₂

The NO₂ with the extreme heat of the engine decomposes creating more O₂. Because there is extra O₂ in the mixture it will create a more complete combustion, heating the internals up too much, therefore more fuel is needed?

From what I've figured out in the last few days that's what is happening. What other possibilities are there? I highly doubt the N would combust with anything, little lone NO which can be found in exhaust normally.

Thanks for any input;

X-18

[Dan]

My question is, when someone runs NO₂ in there car,

Hang on, are you sure you mean Nitrogen Dioxide? or do you mean Nitrous oxide used in racing?

http://en.wikipedia.org/wiki/Nitrous_oxide#Internal_combustion_engine

[X-18]

Hey:

Your right, I have the wrong make up. It is actually N₂O.

After reading most of a Wikipedia page, N₂O will decompose to form N₂ and O₂ at 1300*C:

2N₂O + heat ---> 2N₂ + O₂

Wikipedia said that when the liquid N₂O is sprayed into the intake, it cools the air as it goes from a liquid to a gas, and that makes perfect sense, I don't know the law for that but I've experienced that with butane containers. The other that I didn't read, just a hypothesis, is that as the gas decomposes, it uses the heat, cooling inside the cylinder making it easier for the piston to compress everything thing before combustion. Is that more on the right track?

Thanks:

X-18

[Yggdrasil]

Recall from the ideal gas equation that PV = nRT.  The equation shows that T is proportional to V, so cooling a gas will cause its volume to shrink.  I'm not sure how significant this change in volume is in reality, but theoretically you could increase the compression of the gasses by cooling the gasses.

[constant thinker]

Speaking from a non-scientific standpoint (and more opinion), I think the biggest factor is the extra O₂ provided which creates a more thorough and quicker combustion. More thorough and quicker combustion=more power.

The cooling of the air intake probably is also helpful.

P.S. I personally wouldn't want to use it on a vehicle I own, because it can do a number on an engine according to a couple of friends.

[enahs]

You are correct, in the assumption that the O₂ is the biggest factor.

Some people have tried skipping nitrous oxide and directing pure O₂ from a tank in, but that is too much oxygen and the combustion takes place to fast and overheats the engine and destroys it (which you can still easily do with the nitrous).

[constant thinker]

Even if you could somehow get the direct O₂ injection to work without overheating the engine, it wouldn't last long. I'd have to imagine that the pure O₂ would cause some serious corrosion, and create some very dangerous situations in the event of a leak.

When I was younger I used to think, "Why not just inject pure O₂ into the cylinders." Then I learnt about the chemistry of a car engine, and oxygen in general; which made me realize that it wouldn't work.

[X-18]

Yeah, the temperatures of complete combustion is beyond what the metal can handle. Although it does look kinda cool after when they pull the piston and it has steel drops randomly placed.

When a gas under compression experiences a rapid pressure drop, doesn't the temperature also drop though? Oh, ok, this just just hit me, but is that because the gas has a very low boiling point, and under pressure it would be forced into a liquid, then when it is released it would absorb energy to get it to boil and become a gas? The main issue with that is, I saw a guy make a jet engine (irrelevant but cool) that would rapidly burn propane that was stored in BBQ tank. The tank was inside a ice cooler filled with water, as the tank emptied the temperature of the gas inside dropped, cooling the water. Again irrelevant, inside the water he had his beer, which he later noted was rather refreshing to have after sitting in a garage with a jet in it. I'll look and see if I can find the site for that.

I don't think the ideal gas law has anything to do with the N₂O being released into the intake. It's something else, I just don't know what.

X-18

[X-18]

Found it! 

http://www.asciimation.co.nz/beer/

As a side note, does anyone on this site have jet experience? I'm in the prossess of trying to design and build my own. I've been working on it, mostly researching, for the last month or so. I'm thinking about trying to build a ram jet (just a small 3-5inch diameter and 1-2 feet long depending on diameter) with a fair sized tank on the front to pressure up with an air compressor to simulate high speeds. Mind you, that's another thread.

X-18