Spraying C02 Directing Into Airintake Pipe

[Kaido_RR]

Hi,

Im just looking into design a system which spray C02 mist into the pipe between the AFM and Turbo (basicly very similar design to the C02 FMIC sprayers[i am also in the processe of designing/making one of these])

What i would like to know would spraying CO2 mist directing into the pipe cause any damage to the engine? If so is there a general rule which would determined the amount of CO2 and concentration which causes the most damage.

If it does not affect the engine interms of causing damage, would it affect aspects of my tune (would it be a good idea to get the car retune once the system is setup *i don't like this idea, because i wont be running the system all the time*)

Also for the people that are interested the system i am design is basicly done very similar to a water sprayer on a fmic. i will have it setup so that the system will spray on the press of a button and then another option (on/off button) with preset values (for explain im looking at getting it setup for rpm range between 6000-7500rpm, water temp values and possible boost)

Cheers Michael

[DVS JEZ]

' date='8 Nov 2006, 05:32 AM' post='2650083']

Hi,

Im just looking into design a system which spray C02 mist into the pipe between the AFM and Turbo (basicly very similar design to the C02 FMIC sprayers[i am also in the processe of designing/making one of these])

What i would like to know would spraying CO2 mist directing into the pipe cause any damage to the engine? If so is there a general rule which would determined the amount of CO2 and concentration which causes the most damage.

If it does not affect the engine interms of causing damage, would it affect aspects of my tune (would it be a good idea to get the car retune once the system is setup *i don't like this idea, because i wont be running the system all the time*)

Also for the people that are interested the system i am design is basicly done very similar to a water sprayer on a fmic. i will have it setup so that the system will spray on the press of a button and then another option (on/off button) with preset values (for explain im looking at getting it setup for rpm range between 6000-7500rpm, water temp values and possible boost)

Cheers Michael

hey Michael.

not to sure but i think it might be a bit early in the inlet to be sparying it before the turbo, better off trying to put it near the cooler piping.

just my 2 cents.

curious to see some advantages of it all.

cheers

Jeremy

[wonkynutz]

I'm not sure if spraying CO2 into your intake will help matters.Obviously you'll get a cooler charge but you'll also effectively be replacing oxygen with CO2.That won't help power output.For the same amount of stuffing around you may as well squirt in nitrous to get the same cooling effect and more burnable oxygen.

[Techo]

CO2 is what is produced AFTER you burn fuel (along with a whole host of bad chemicals) it is non flammable, & if you read the instructions on just about ANY CO2 kit it will tell you to keep the intercooler sprayer away from the intake pipe.

If you are keen on spraying something into you intake to cool inlet temps, as stated above go with nos, or water/methanol injection, or even propane(starting to get big in the states for drag cars).

Otherwise, if you already have the CO2 kit & are keen on using it set it up so that it sprays ONTO the intercooler or a intake pipe.

Just a side note that they make kits that have a teardrop shaped bulb inside a pipe which is fitted into the intake piping. when the CO2 goes thru it on its way to the intercooler sprayer it gets super cold & cools the intake charge that way.

I hope this helps,

Regards,

Jeff

[Munna1]

I looked into this mate (to much muching around for my liking) there is an artile on autospeed.com.au its worth a look as they tell you what nossle (very fine) you need etc. It would work but a lot of fine tuning would need to be done to get it set up and tuned right a 50/50 water/methonol would be best.

Dont fit the sprayer before the compressor wheel as the water particles will pit it over time.

cheers

[Munna1]

http://autospeed.drive.com.au/cms/A_0115/article.html

Here you go

[mad082]

CO2 doesn't burn. i was looking at doing this since i can get CO2 cartridges through work. then i found out it isn't flammable so i was going to look at hooking it up to a spray system so it sprays onto the cooler.

but scrapped that idea. now i'm just going to go with waterspray or water injection.

[blind_elk]

...you'll also effectively be replacing oxygen with CO2...

That's why they use it in fire extinguishers!

And it's why people die in CO2 rich environments.

[GeeTR]

Seriously, no offence dude, but to title a thread "Spraying Co2 directing into Airintake Pipe" then spend 10mins writing a question, asking, will it hurt your engine, will it effect tuning… should be a sign within itself.

All the systems you mention for removing intake charge temp, work in vastly different ways, and can cause some fairly catastrophic results; its not lego, and you cant mix and match.

I would suggest

- decide your intended end results, as lower intake temps wont automatically mean more power, if your fueling / ignition system doesn’t take advantage of it.

- research your options, until you understand the physics of each

- design develop and document a system, posting specific questions as you go, then post the results for us all to read!!!

Cheers

M

[fr0st]

Just thinking out loud...

Your injecting an inert gas into the inlet pipe, which lowers temperature (reducing pressure) but also adding more gas (raising the pressure). If you injected the gas and had the same amount of air and fuel in the cylinder as usual but with some CO2, it would have a similar charge size as without the CO2 since its denser.

Since the CO2 won't burn, its just sitting in there taking up space, wouldn't that increase the compression ratio?

Something like -

Mixture 1 is a normal inlet charge, normal temperature

Mixture 2 is denser because its cooler, but now has CO2 in it so it takes up the same volume as mixture 1.

If you burned mixture 2 in a cylinder what would happen?

It would still burn, but there is less space for the fuel/air to be compressed into because of the presence of the CO2, therefore higher compression ratio and higher chance of pinging?

[Freddy Kruger]

from what i understand from the little research on it is that you run a pipe or something around the intake or thru it to cool it down, and only spray it over the intercooler surface to cool it down.

if you want to cool your car at the drags buy a fire extinguisher and spray it on the intercooler before a run or something just to bring temps down.

[blind_elk]

They use CO2 in fire extinguishers - I wonder why?

The problem, fr0st, is that the presence of CO2 in the charge is severely altering the ratio of available O2 to fuel, resulting in an over-rich A/F ratio.

[Kaido_RR]

Thanks for the reply everyone

Let me just state a few things:

im current a student doing mechanical engineering (hope i can put some of my study to use )

the system is just to keep temp down, im not looking for any power gains

Looks like there are too many factors spraing into the airintake pipe, so that idea is now gone.

I have been thinking about another possible item.

If i can somehow create a cover over the i/c piping and have a gap between pipe 1 and the blanket. then spray the co2 into the gap to cool the pipe itself....

i have yet to do any calucations or anything like that jus throwing ideas out tring to find the best way to go about this

ALSO, im just doing this for some fun and something to apply my engineering skills; so the options of using nos, or water/methanol injection are not on the cards

Thanks Michaels

[fr0st]

They use CO2 in fire extinguishers - I wonder why?

The problem, fr0st, is that the presence of CO2 in the charge is severely altering the ratio of available O2 to fuel, resulting in an over-rich A/F ratio.

I'm not entirely sure it would, atleast not severely.

Any air past the turbo has to either go through the engine or recirculated and your not passing any CO2 through the AFMs. CO2 isn't combustible so it won't lean you car out like an air leak would. When you injecting it into the inlet pipe your raising the inlet pressure, so the turbo doesn't have to work as hard to keep the pressure up meaning less air is drawn through the AFM = less fuel.

It also mean less fuel and air in the cylinder which isn't a good thing for power

[fr0st]

' date='8 Nov 2006, 02:15 PM' post='2651537']

If i can somehow create a cover over the i/c piping and have a gap between pipe 1 and the blanket. then spray the co2 into the gap to cool the pipe itself....

Your forgetting with pipes that the layer of air touching the pipe isn't moving. All the air passes down the middle of the pipe, air isn't like water in the sense that if you cool the outside it will transfer to middle. I don't think it would have the slightest effect on inlet temperature purely because there isn't enough surface area and the air is moving too fast. If you introduced more surface area in the pipe your creating a restriction and you'd lose power at the expense of temperature.

If you spray the inter cooler you already have plenty of surface area to work with and you not adding any further restriction to the inlet pipes.

[Kaido_RR]

froSt i mean something like this

so that for the total length of the pipe there would be say a 10mm gap where the co2 will be directly spray into. the grey section will be close off so that it will only have co2 in it

arr im tied, going to have a nap then i will try and explain wat im thinking in my head

ahah

Michael

[fr0st]

I get what your trying do but I don't think it will have the results you want.

RE: you comment in the wasteland about CO2 being natural cold. The cold comes from releasing a high pressure gas into low pressure. Its the opposite of what turbo's do - air goes in, gets compressed and heats up. Whereas with CO2 its compressed and getting released to atmo so it absorbs heat. You can do it with any gas, n2o for instance.

Google refrigeration if you don't get what I mean, I'm crap at explaining things lol

The main problem with what your trying to do is surface area. How much of the air going through the pipe will touch the pipes cold surface?

and at the rate that the air is moving, how much time will it be in contact with the pipe?

Air is an insulator so if you cool it, it won't transfer the 'cool' around to the rest of the inlet charge very well.

Take your inter cooler as an example. The fins inside increase surface area to the inlet charge while the fins on the outside increase surface area to the ambient air. Most surface area mean more contact with a cool surface = better cooling.

Another thing is the amount of bars/tubes in the inter cooler. The larger the inter cooler, the slower the air moves through it. Kind of like sucking on a straw vs. sucking on a hose to get the same amount of water out. Water has to move faster through the straw to keep up with the hose. This increases the time that the air is in contact with the inter cooler fins, so you get more cooling.

The inter cooler is probably the perfect place to spray CO2, not too mention the easiest

[Big Rizza]

Just thinking out loud...

Your injecting an inert gas into the inlet pipe, which lowers temperature (reducing pressure) but also adding more gas (raising the pressure). If you injected the gas and had the same amount of air and fuel in the cylinder as usual but with some CO2, it would have a similar charge size as without the CO2 since its denser.

Since the CO2 won't burn, its just sitting in there taking up space, wouldn't that increase the compression ratio?

Something like -

Mixture 1 is a normal inlet charge, normal temperature

Mixture 2 is denser because its cooler, but now has CO2 in it so it takes up the same volume as mixture 1.

If you burned mixture 2 in a cylinder what would happen?

It would still burn, but there is less space for the fuel/air to be compressed into because of the presence of the CO2, therefore higher compression ratio and higher chance of pinging?

Also thinking out loud...

I doubt CO2 injection would add more gas and raise the pressure because the inlet piping it is open to atmosphere at one end (hence pressure won't build up), so it's going to displace the oxygen and slow the incoming air through the intake prior to the injection point.

Compression ratio is mechanical, so isn't effected by the composition of incoming gas. But the air density will have positive affects the volumetric efficiency i.e. more gas gets into the cylinder per stroke.

Getting the right amount of CO2 injected would be pretty tough without extensive testing IMO. Too little CO2 and there be negligible effects. Too much CO2 and there won't be enough air and you would lose power as the engine can't burn enough fuel. Using the factory airflow meter and a multimeter might give you some assistance during the testing phase, and allow you to see how much CO2 flow you can give before incoming air is affected, but still, I seriously doubt that finding a middle ground where enough CO2 is injected to cool the air, but not so much that the air is displaced, will be a simple task able to be undertaken by an undergraduate in his spare time, and even if that middle ground is found, I beleive any gains will be negligible.

' date='8 Nov 2006, 02:15 PM' post='2651537']

Thanks for the reply everyone

Let me just state a few things:

im current a student doing mechanical engineering (hope i can put some of my study to use )

the system is just to keep temp down, im not looking for any power gains

Looks like there are too many factors spraing into the airintake pipe, so that idea is now gone.

I have been thinking about another possible item.

If i can somehow create a cover over the i/c piping and have a gap between pipe 1 and the blanket. then spray the co2 into the gap to cool the pipe itself....

i have yet to do any calucations or anything like that jus throwing ideas out tring to find the best way to go about this

ALSO, im just doing this for some fun and something to apply my engineering skills; so the options of using nos, or water/methanol injection are not on the cards

Thanks Michaels

How about just a simple water spray install? Water is cheaper and easier to deal with than CO2 cylinders, and it won't kill you if you forget to turn off the bottle in a small enclosed garage. Plus, you get the added benefit of not forming carbonic acid whenever you use your CO2 intercooler spray in the rain! It gives you some design experience (what water pump to use? what nozzle? where to install? where should the spray be directed? how long should the spray stay on for?), plus some basic electronics (where will you obtain a power source? how will you control the duration of each spray? how will you activate the spray?)

Once you've got that sussed, you can get into some control systems (something undergraduate mechanical engineers tend not to appreciate enough in my opinion!). This way, you can have the water spray come on automatically under certain conditions, and you just need to focus on driving. Working out what inputs you would use would be an interesting design exercise. Would you use a simple temperature switch so that it turns on when hot, then off again when it's cooled? Maybe a boost switch, so it sprays whenever the car is on boost? Maybe you could link it to the boost control solenoid (depending on your vehicle type) such that it comes on automatically when boost is vented (usually meaning full boost has been reached). Problem is, not all cars have such a boost control system as standard. Maybe an RPM switch, such that it comes on over 3000rpm? Maybe link it to the air flow meter output, so that it comes on a high airflow? Maybe injector duty cycle, so it comes on when the engine is under load? Most of these signals can be obtained from sensors already in your car from the factory, all you need is a simple voltage switch and a multimeter. Or if you want to keep it REALLY simple, just stick a switch under the accelerator pedal so it comes on automatically at full throttle!

Sounds like an awesome project... I might have to undertake it myself!

Edited November 8, 2006 by Big Rizza

[fr0st]

snip

Sorry I wrote that thinking he was going to inject it after the turbo.

Isn't static compression mechanical but dynamic compression related to the inlet pressure? Hence why turbocharged engines run a lower static compression because they achieve a higher dynamic compression under boost.

I'm an electronic engineering student so I'm probably wrong

Control systems I can do... search ebay for a hobbs pressure switch, I think there about $30. They're adjustable to activate from something like 3- 10psi.

If you want to get even more complicated you can make a little thermistor circuit to throw a relay over a certain temperature. In series with the pressure switch you'd have a sprayer that would turn on when the temperature has risen and your boosting it.

[Devils_Advocate21]

Go with nos less hassel much cheaper less stuffing arround, and plus wouldnt adding a sleeve on the ic piping cause some serious condensation side the ic piping? it should do as your car isnt just sucking in O2 out of the are theres alot of other matter like water molecules and also nitrogen, must take into affect the moisture issue raised with a CO2 sleeve on IC piping i say.

Good luck otherwise and atleast money for those just in case moments

Cheers