Injecting water into an internal combustion engine
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40wav,
Jul 20, 9:34am
I've heard that some people have tried injecting a mist of water into the combustion chamber of an engine with the fuel to create higher combustion pressures and thereore more power. If this works on the theory that the water does not compress and therefore reduces 'space' in the combustion chamber, is this not just the same as having a smaller combustion chamber (i.e. a longer stroke on the piston)! Or is the theory that the water will turn to steam in the process (taking up more space) and provide a larger reaction than it's initial self! Haven't really given it much thought till now. Cheers.
mm12345,
Jul 20, 9:45am
AFAIK, it's actually used to reduce pre-ignition and improves cooling, so rather than be used to increase cylinder pressures, it can be used to mitigate the downside of high cylinder pressure - from high compression ratio, forced induction etc.
skull,
Jul 20, 9:46am
I don't think it is increasing the combustion pressure by reducing the volume, it's a mist so bugger all volume in that. I think because water is H2O there is more oxygen available for the combustion. Probably be shot down in flames but that's my theory. Jazz will be along to kick my butt and tell us how VW invented and perfected it by discarding the oxygen and using the hydrogen.
pollymay,
Jul 20, 9:46am
It steams and cools the chambers, helps stop detonation and cleans the chambers. Water/meth injection is common on turbo cars as a means to increase power by cooling the intake charge, cooler intake charge = denser air, denser air = bigger bang = more power and with the cooler charge you get the added benefit of detonation resistance compared to a hot charge. Can also be used to lean out the AFRs on load to decrease fuel requirements.
EDIT: can also run a bit more advance if you do it right. Do it wrong and you'll just blow up your motor or something. Fun stuff
jason18,
Jul 20, 9:47am
I just poor a jug full in the spark plug holes. Works a treat.
Can you take a video of this I am keen to see what happens.
johnf_456,
Jul 20, 10:52am
Have the translator ready
snoopy221,
Jul 20, 11:36am
Gor Blimey Hydrogen and 2 oxygens. and whaddya want! Cooler intake charge and a couple of extra added oxygen molecules! Tranny dat. well if ya donna schwing. both ways. juss readit.LMAO
snoopy221,
Jul 20, 11:37am
Good ole pollmay is,,, well sorta onto it.
purple666,
Jul 20, 11:37am
Thats the answer, more power, less heat and a lovely clean combustion chamber and piston crown.
snoopy221,
Jul 20, 11:40am
just poor a jug full in the spark plug holes. Works a treat.
Quote jason18 (825 )9:47 pm, Fri 20 Jul #5
MEH.L M A O. goes in spec wifff a 3.5 power valve on a 7fiddy D P. (Adds Tui-.Yeah Roit)
the-lada-dude,
Jul 20, 8:52pm
squirting water into an intake manifold will have a cooling effect on the temperature of gases, the finer the water droplets probably the better. ( latent heat of evaporation ) = a drop in intake temp = higher intake charge weight, and will help retard spontaneous combustion. results vary and therefore are open to experimentation. once the intake valve is closed the effect of water turning to a gas has little affect as heat is being robbed from either the fuel or air ( you would have to check the various vapour pressures of all the components within the cyl ) but the major benifit is the water vapour becomes a barrier to the flame front.slowing its progress and allowing a controlled burn rate thus avoiding pre ignition or the engine killer DETONATION. just imagine a container with air ( a mixture of gasses, most contribute nothing to the combustion process, it's the oxygen that really provides the bang. ) and a fuel as a gas. if you add a heat source to get a reaction between the gasses going there is going to be a good exothermic reaction ( a nasty bang, sore ears and singed eyebrows )as there is nothing to hinder the mixing of these 2 gasses. if you throw water gas into the mix the reaction gets slowed down as the flame front has to dodge around those particles that don't burn.this water injection system was used extensively on the big super charged radial air cooled engines
budgel,
Jul 20, 11:31pm
Another effect of water injection seems to be that the combustion chamber and piston top stay free of carbon buildup.
I bought a Nissan 720 ute that had a very small hole in the head that was losing a small amount of water into the cylinder and didnt effect performance in any way until it flooded the cylinder. No antifreeze had been used for years.
When I took the head off, the problem cylinder was as clean and shiny as if it was brand new.
An old engineer I knew who had been playing around with water injection for years reckoned that was commonplace on water injected engines.
He claimed that it enhanced atomisation of the fuel hence a more complete burn with associated economy benefits.
He also claimed that for run of the mill cars it was of marginal benefit when modern fuel injection systems became common, because of their much better atomisation compared to carbed engines.
elect70,
Jul 21, 2:30am
Used onhi pressure turbo engines to cool theair/fuel charge to prevent detonationAFAIK
You can pickup a Aem kit for around 500nz, I'll be running one on the sti once i sort out the hybrid hx40 pro turbo and G4 will be running the AEM kit through the eboost2 boost controller to save cost. Am looking around the 30psi mark :) have about half of the gear already and should have it sorted by X-mas. Can't wait!
hijacka,
Jul 21, 8:02am
I will be running a Link G4 ecu with 5bar map sensor and 1000cc top feed injectors i already have the turbo, its currently at crank engineering getting machine to suit the bigger comp wheel and have a .63 exhaust hsg with v-band in the mail and got 44mm turbo smart progate W/G and top feed conversion kit and rails just need to save up for the G4 and injectors andnot to mention the fabrication and tig welding thats going to be needed will be booking it in at petes customs in the next couple of weeks, he is booked out for the next 6weeks so that should give me plenty time to save by the time i book it. Just got hide to actual cost of this venture from the misses lol
hijacka,
Jul 21, 8:14am
My car has turned into a endless money pit, can't turn back now! already in way over my head lol
hijacka,
Jul 21, 8:21am
cost saving!. What is that and How does that work! lol
r.g.nixon,
Jul 21, 8:23am
Meh, move up to the next level. Nitromethane works better!
bmc460,
Jul 21, 9:43am
hot farm pulling tractors have water injection diesels
captjohnson,
Jul 21, 10:53am
I have heard of people getting extremely good results doing this with diesel engines injecting the water/methanol mix or just water pre turbo it cools the engine down considerably and the steam then cleans the engine. Cooler cleaner engine = more efficency and therfore more power. Also adding in the methanol helps the diesel to combust as a average diesel engine only burns around 90% (from memory) of the fuel the rest gets flicked out the back as carbon! well the methanol combusts that extra bit and gives you more power. Once i get some $$ i am going to do it on my surf =Dhttp://www.alcohol-injection.com/en/
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