First attempt at a Water Injection table....opinions please.

Discussion pertaining to positive pressure E28s.
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Duke
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First attempt at a Water Injection table....opinions please.

Post by Duke »

Image

GPO duty cycle will be % ouput of the WI pump. Not sure of the nozzle size yet.
russc
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Post by russc »

I don't see a big problem with that. The % output rises with pressure and RPM. That seems to be what it should look like.

I guess the question is, does it work?

RussC
Duke
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Post by Duke »

russc wrote: I guess the question is, does it work?
RussC
Work how?

You mean to be able to run lower octane fuel and still run same amount of boost.....yes.

Or, run much more timing for more HP....yes

Or, run much higher boost for more HP due to the cooling without detonating....yes.
russc
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Post by russc »

Well,
Great, thats beautiful. Looks like your going to.

RussC
altus22
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Post by altus22 »

I suggest that you log the intake temps at different rpm and boost level to see how much water you need injected. I wonder if MS autotune could be set up to do that for someone. Hmmmm...
russc
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Post by russc »

altus22 wrote:I suggest that you log the intake temps at different rpm and boost level to see how much water you need injected. I wonder if MS autotune could be set up to do that for someone. Hmmmm...
I believe that MS can.

RussC
FSAEracer03
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Re: First attempt at a Water Injection table....opinions ple

Post by FSAEracer03 »

Duke M535ti wrote:Image

GPO duty cycle will be % ouput of the WI pump. Not sure of the nozzle size yet.
Looks like a solid graph (mimicing the boost curve, it appears, as it should). I have two questions though.

1) Did you calculate the maximum water flow-rate using the latent heat of vaporization and how much can and will actually be fully vaporized with your boost level, engine size, and intake temps... or is it an arbitrary value you just picked?

2) What program is that on? That's a really slick WI control setup!!

I can't wait to see the before and after dyno pulls!
M635CSi
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Post by M635CSi »

I think there are two issues here; 1) the amount of water able to be vaporized in the intake tract as a function of a) H2O nozzle design/placement, b) intake charge temperature, c) boost pressure, and d) intake charge velocity and 2) the amount of water that can be injected into the cylinder before BMEP deteriorates.

If the goal is to cool the intake charge and forestall detonation, it should be possible, given the placement of the water injection nozzle and particle size of atomization, to arrive at how much water can be vaporized given a particular pressure/temperature/velocity fact pattern.

If the goal is to cool the engine/combustion chamber through water injection beyond the maximum amount of water able to be vaporized by the intake charge, then in this case, I believe water injection at the intake port or cylinder is the only way. Individual injectors can atomize sufficient water into the intake ports/combustion chambers. Injecting that quantity of water anywhere but the intake port or cylinder will result in water falling out of suspension and reduced cooling…

Kudos on all the great results you're getting Duke!!!
j9fd3s
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Post by j9fd3s »

http://ausrotary.dntinternet.com/forums ... hp?t=38929

rx7 guys are haveing a big feud over water vs alcohol injection, they both work really well....

mike
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