Why not use gaseous nitrous instead of liquid?
Thread Starter
Joined: Jan 2002
Posts: 1,802
Likes: 36
From: Dutchess, New York
Why not use gaseous nitrous instead of liquid? So I work as a gas engineer, and we use a significant amount of ultra-high purity nitrous oxide on site for industrial purposes, which we get in 22,000lb trailers. Being that its a liquid with high vapor pressure, for our use we pull off the gas for use which is around 650-700psi of cylinder pressure. Now I know for automotive useage, the nitrous is injected as a liquid and then evaporates, as you use a bottle with a dip tube at 900-1110psi, and suck off the liquid, using the gas pressure to force it out. Part of the reason I know is because of the great cooling effect you get evaporating the gas. I'm guessing also its mainly to get enough flow of nitrous.
But anyways I'm curious as to why gaseous nitrous couldn't be injected instead? True you would miss out on the cooling effect from the evaporation. But you'd still be picking up the power from adding the oxidizer. If flow was a problem you could run a larger diameter line, or multiple lines. Heat the bottle a bit, and you could probably get 800psi bottle pressure out of it, but with a larger line, you'd still get the same flow. This way you could put a regulator on it, and have fairly consistent pressure being delivered to the motor, save some regulator droop. Might not help for max power, but I'd imagine it would be good for bracket consistency. I could see where you'd have to run a wet kit though, as I don't think a MAF would be able to meter it.
I dunno, just randomly curious
But anyways I'm curious as to why gaseous nitrous couldn't be injected instead? True you would miss out on the cooling effect from the evaporation. But you'd still be picking up the power from adding the oxidizer. If flow was a problem you could run a larger diameter line, or multiple lines. Heat the bottle a bit, and you could probably get 800psi bottle pressure out of it, but with a larger line, you'd still get the same flow. This way you could put a regulator on it, and have fairly consistent pressure being delivered to the motor, save some regulator droop. Might not help for max power, but I'd imagine it would be good for bracket consistency. I could see where you'd have to run a wet kit though, as I don't think a MAF would be able to meter it.
I dunno, just randomly curious
Thread Starter
Joined: Jan 2002
Posts: 1,802
Likes: 36
From: Dutchess, New York
Shouldn't be any difference in size, since you're evaporating off gaseous nitrous from the liquid nitrous in the bottle. Basically you'd use the same size bottle as one generally uses, but leave out the dip tube. The vapor pressure of the nitrous evaporating in the bottle what would supply the gas pressure. Basically the same thing that is done with Propane (Liquified petroleum) - its a liquid under the high pressure in the container, which evaporates off and creates pressure as it is drawn on.
TECH Regular
Joined: Jan 2004
Posts: 426
Likes: 4
From: Austin, TX
A couple of things come to mind. First, the size of the lines nozzles and solenoids would need to be many times bigger to move the same quantity of vaopr as liquid.
Second, If you pulled vapor from the tank, the flashing of the liquid to vapor inside the tank would quickly cool the remaining liquid in the tank to the point where the pressure would drop to almost non-existent! Only after the liquid warmed back up would the pressure return. In order to keep the pressure fairly constant, you have to flash the liquid to gas external to the tank so that it does not cool the tank off.
Regards, John McGraw
Second, If you pulled vapor from the tank, the flashing of the liquid to vapor inside the tank would quickly cool the remaining liquid in the tank to the point where the pressure would drop to almost non-existent! Only after the liquid warmed back up would the pressure return. In order to keep the pressure fairly constant, you have to flash the liquid to gas external to the tank so that it does not cool the tank off.
Regards, John McGraw
Originally Posted by John McGraw
A couple of things come to mind. First, the size of the lines nozzles and solenoids would need to be many times bigger to move the same quantity of vaopr as liquid.
Second, If you pulled vapor from the tank, the flashing of the liquid to vapor inside the tank would quickly cool the remaining liquid in the tank to the point where the pressure would drop to almost non-existent! Only after the liquid warmed back up would the pressure return. In order to keep the pressure fairly constant, you have to flash the liquid to gas external to the tank so that it does not cool the tank off.
Regards, John McGraw
Second, If you pulled vapor from the tank, the flashing of the liquid to vapor inside the tank would quickly cool the remaining liquid in the tank to the point where the pressure would drop to almost non-existent! Only after the liquid warmed back up would the pressure return. In order to keep the pressure fairly constant, you have to flash the liquid to gas external to the tank so that it does not cool the tank off.
Regards, John McGraw
This is why you want to keep the temp high enough to maintain a liquid in the tank but not high enough to go supercritical.
Thread Starter
Joined: Jan 2002
Posts: 1,802
Likes: 36
From: Dutchess, New York
Originally Posted by John McGraw
Second, If you pulled vapor from the tank, the flashing of the liquid to vapor inside the tank would quickly cool the remaining liquid in the tank to the point where the pressure would drop to almost non-existent! Only after the liquid warmed back up would the pressure return. In order to keep the pressure fairly constant, you have to flash the liquid to gas external to the tank so that it does not cool the tank off.
Regards, John McGraw
Regards, John McGraw
FWIW actually we had our nitrous trailer system go supercritical this summer on a 97 degree day and high flow. Came out to a regulator in the supply cabinet encased with about 2" of ice all around. I'm going to end up having to install a sprinkler system of sorts to chill the tubes before next summer rolls around to keep it from occuring again.
Thanks for the input
I've only been doing cylinder gas engineering for about 5 months or so, so I'm constantly learning, and dealing with nitrous use on the industrial level made me interested to see what could be transfered to the automotive level. Lol and also considering I just bought a Nitrous Outlet wet kit. 
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TECH Addict
Joined: Aug 2004
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Likes: 4
also worth thinking about is the fact that 200bhp worth of N2O as a gos would take much MUCH MORE volume than 200bhp worth of N2O as a liquid! thats why people like to use direct ports systems cos you get almost all the N2O into the cylinders as a gas, therefore not sapping NA power.
thanks Chris.
thanks Chris.
Thread Starter
Joined: Jan 2002
Posts: 1,802
Likes: 36
From: Dutchess, New York
Originally Posted by 02 BLK WS6
Easier to control and measure a liquid than a gas.....
But I do think as the previous poster stated the huge volume is the biggest problem, and probably why liquid is required.
I've been asking this for a long time:
Why not flash over externally and use a regulator to provide consistency.
I don't think that rapid release is as pronounced in nitrous as it is in something like CO2, is it? Not sure on that one.
I mean, increase lines and/or line diameter, and you have potential for great consistency. That's why paintball guns went to nitrogen for a while. It has more pressure consistency when released, and when delivered as a gas (after filters and regulators), is super-consistent.
Why not flash over externally and use a regulator to provide consistency.
I don't think that rapid release is as pronounced in nitrous as it is in something like CO2, is it? Not sure on that one.
I mean, increase lines and/or line diameter, and you have potential for great consistency. That's why paintball guns went to nitrogen for a while. It has more pressure consistency when released, and when delivered as a gas (after filters and regulators), is super-consistent.
Originally Posted by N4cer
I've been asking this for a long time:
Why not flash over externally and use a regulator to provide consistency.
I don't think that rapid release is as pronounced in nitrous as it is in something like CO2, is it? Not sure on that one.
I mean, increase lines and/or line diameter, and you have potential for great consistency. That's why paintball guns went to nitrogen for a while. It has more pressure consistency when released, and when delivered as a gas (after filters and regulators), is super-consistent.
Why not flash over externally and use a regulator to provide consistency.
I don't think that rapid release is as pronounced in nitrous as it is in something like CO2, is it? Not sure on that one.
I mean, increase lines and/or line diameter, and you have potential for great consistency. That's why paintball guns went to nitrogen for a while. It has more pressure consistency when released, and when delivered as a gas (after filters and regulators), is super-consistent.
you can do whats called a nitrogen push....
thats where you take nitrogen, and regulate it into the nitrous bottle, so that it puts a constant head pressure on the liquid nitrous.
the only reason you dont see it commonly used is that its not legal in most sanctioning bodies for competition...
On The Tree
Joined: Jun 2004
Posts: 117
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From: Albuquerque, NM
Nitrogen in Paintball guns is run off of compressed gas, 3k-4500 PSI kinda like SCUBA tanks but smaller. The regulation generally occurs in two stages. the first is at the bottle, where the gas is regulated down to 1kish PSI at optimum flow, and a second near the bolt/propellant area to get the pressure down to usable range for the gun (3-900 PSI depending on application) "Nitrogen" tanks are still comonly used, much more common in higher end guns, however its not liquid nitrogen like the CO2 is. In fact they usually arent even filled with pure nitrogen anymore, just compessed ambient air which is stable enough for our use.
However, CO2 paintball gun users do have a few other tricks. namely, the use of an expansion chamber. basically, using a chamber filled with baffles that aid the expansion of the CO2 into a gas, allowing more consistancy of flow. However these rarely use a regulator, and the length of lines we use for nitrous on cars is probablly sufficient to aid in the expansion, and once the nitrous hits the intake manifold, thats like the ultimate expansion chamber.
The main probalm is volume of gas required (or pressures required to stableize the gas with a small enough volume). then getting regulators with enough flow and consistancy would probablly be quite pricey.
-Josh
However, CO2 paintball gun users do have a few other tricks. namely, the use of an expansion chamber. basically, using a chamber filled with baffles that aid the expansion of the CO2 into a gas, allowing more consistancy of flow. However these rarely use a regulator, and the length of lines we use for nitrous on cars is probablly sufficient to aid in the expansion, and once the nitrous hits the intake manifold, thats like the ultimate expansion chamber.
The main probalm is volume of gas required (or pressures required to stableize the gas with a small enough volume). then getting regulators with enough flow and consistancy would probablly be quite pricey.
-Josh