Water injection

[helen&tony]

Hi
A technical question...Does anyone have any experience of water injection with diesels? Firstly, is water injection suitable on a diesel, especially turbocharged diesels. If feasible, would it be more suitable to spray into the inlet manifold after the turbo, as the water mist may damage the turbine blades if injected pre-turbo? On the other hand, would it be a better consideration to modify the head to directly inject the water mist into the cylinder, or would the thermal shock reduce the life of the piston crown. If there is no chance of piston damage, would the water charge have to be timed to enter the cylinder before the fuel, to decrease the temperature in order that when the fuel charge enters, the cooler atmosphere allows a denser charge of fuel/air?
As for my purposes, I do not wish to go about modifying the head, but post- turbo injection is quite feasible.
I have noticed over here that after a long , hot , dry spell, a day when there is misty rain produces a massively noticeable increase in both perceived power and throttle response, so I may well think of trying a system out, if post-turbo injection is possible.
The system I wish to try would sense sharp throttle movement, and spray into the inlet upon acceleration.
Any thoughts or comments gratefully received and considered.
Cheers
Helen

[manners]

Water is usually sprayed onto the intercooler to reduce the temp, I might be wrong but ive not seen anything that sprays water into the mix.

[francophile1947]

No experience at al, but it seems to be another of those disputed claims (see http://www.biodieselnow.com/forums/p/16911/127813.aspx and http://hackaday.com/2005/06/25/home-bui ... /#comments )
Engines definitely run better in damp weather, but how easy is it to replicate those conditions? Probably less of a benefit in the UK than in a Bulgarian summer

[Biobongo]

Have a look at these, parts 1 & 2. Talks about petrol & diesel. It is an interesting topic See in part 2 how over dosing will cause hydraulic locking on diesel, very nasty. Not for me, but technically, already being done by the 'industry'.

http://autospeed.com/cms/A_110212/article.html
http://autospeed.com/cms/A_110369/article.html

[helen&tony]

Hi
Water injection is old technology (pre-war), and , in fact was used on Messerschmit plane engines to extremely good effect...It has been tried on and off since, and one firm was offering a bolt -on -kit to add to the 1000cc/1300cc Kawasaki engine many years back, and I seem to remember good results.
Biobongo:
That article is quite interesting, although I seem to think it's a case of charge density rather than cooling. as I often noticed on a hot day in England, when I flew my rockets using a Nitrous Oxide oxidiser, that if I remotely loaded a pound or two of nitrous in the tank, and then dumped it, it would lower the tank temperature, enabling me to put more gas in on a second fill...denser charge, more available gas....MORE OOOMPH
Franco
Regarding being more advantageous over here...maybe not...the first practical sign I ever saw of water in the air mix was in1967, when I worked in Harrow in an office. One chap in the office used to drive from Harrow to Sittingbourne every day, (goodness knows why???), and every time there was a damp evening on his return trip, he could actually time a much quicker journey...factoring in traffic conditions, I cannot imagine that the overall speed was higher, but the engine was more responsive in overtaking/ running....so I reckon many days would be suitable in England....but I would hazard a guess that it would be worth turning the system off in a downpour or very damp air
I think, seeing that article, that it maybe worth a punt if I could source some parts here during the boring months
I am still thinking post-turbo, as if the mist is efficient , I doubt very much that locking would be a problem...it just needs investigating as to how easy it is to mist the water
Cheers
Helen

[francophile1947]

I am still thinking post-turbo, as if the mist is efficient , I doubt very much that locking would be a problem...it just needs investigating as to how easy it is to mist the water
Cheers
Helen

Wouldn't pre-turbo be better The idea of the water is to cool the air, so I would have thought it better to have it in the air intake as long as possible (more evaporation and cooling )

[helen&tony]

Hi John
Yes...ideally, but i've got nagging suspicions on water on red-hot turbo blades producing a lower temperature on the front edge , or face, of the blade and the rear at a higher temperature, making an unequal temper through the blade and resulting in shattering after continuous use....I suppose if the water was misted far enough away from the turbine, this would be minimised, but how far is far for the purpose of experimentation, and in cooler airflow, if it was too far away, would the droplets fall out of suspension in the air mix?
Cheers
Helen

[waycar8]

Hi John
making an unequal temper through the blade and resulting in shattering after continuous use....I suppose if the water was misted far enough away from the turbine, this would be minimised, but how far is far for the purpose of experimentation, and in cooler airflow, if it was too far away, would the droplets fall out of suspension in the air mix?
Cheers
Helen

,






nope sorry Helen thought I knew what yall was talking about and thought of a solotuion then I realised I was thinking of a bread making machine

[bigdaddycain]

Hi Helen, with the "Aquamist" system, a mix of cold water vapour, is sprayed onto the intercooler (intake side) which then lowers the overall output charge temp, at no stage is any water introduced into the actual turbo... The principle is based on lowering the intake temp of the air,effectively it's the same as fitting a bigger intercooler with a larger cooling surface area, without the added hassle of fabricating new mounts for a bigger cooler, epense of sourcing a bigger cooler etc... My mate used to put screenwash (?) into the aquamist reservoir for added cooling, apparently the santa pod guys often did this to further lower the intake charge temps!