TexasHardcore

OK, here's the deal...

My brother and I were sitting down at some drag races in San Antonio a few weekends back. He's new to turbos, and doesn't know much about diesels. Since our shop was a vendor/sponsor for the event, we had alot of turbos on hand and we were helping people understand how they work, and what could be done with them. He asked me a question, and we talked about what we thought it would do...we'll get to that in a second...

Since I'm also new to diesels...I might be asking something that has already been done, or just plain won't work.

I understand the water injection, I understand the propane injection, and I understand nitrous oxide injection...and I don't plan on using any of them because I'm a broke whiteboy and my '92 CTD is my daily driver and I don't feel like replacing/rebuilding a motor.

Here's the skinny...

Steam Injection... A water reservoir, inline pump, copper tubing wrapped around the outlet neck of the turbine housing/downpipe, with a nozzle directed into the inlet side of the turbine housing.

This nozzle injects steam into the exhaust gases entering the turbine wheel/housing. This should INCREASE exhaust pressure, throughout the RPM band. Basically making more exhaust pressure at any RPM than the motor would without it. This would result in quicker turbine spool up, and less engine RPM's to make that turbine spin.

This SHOULD also lower EGT's when used, since it's not taking as much power from the engine, ie, power=heat. It should also lower the temps in the turbine housing.

We're thinking there shouldn't be any negatives to this theory, since nothing is directly injected INTO the intake, compressor, or engine itself.

I'm sure it wouldn't make a whole hell of a lot of difference in power...but it could maintain lower EGT's while raising exhaust pressure, and increasing spool up and boost pressure with less engine strain.

Maybe we're overlooking certain important facts, maybe we're talking about something that is already being done, maybe we've stumbled upon a cheap, easy way to make a bit more power without sacrificing anything???

If anyone could help with this...please add your comments... Maybe my brother and I are dumb to you, but realize this was just something that popped into our heads, since we've never heard of it before.

I've searched this forum, as well as others for "steam injection" and "steam" and haven't really found any topics that relate to this...

well....have at it...

thumper 549

Well I think your on to something here and better patt. in a hurry. I cant figure out why it already has not been done but evry good idea has to start somewhere
Diesel inj of pittsburg was messing with direct h2o ....do not know the results..........keep us informed i vote it a great idea!!

AlpineRAM

I'll throw in my 2c here. I think that the pressure you induce by injecting the steam will also make it more difficult for the engine to scavenge during valve overlap. Since the turbos do work of delta enthalpy (difference of heat*pressure) and you do inject some much colder fluid or steam into the exhaust gas this could throw you off the map significantly enough to neuter the beneficial effects of transporting energy from the ambient (exhaust past turbo) to the inlet of the turbine.
Something else to consider would be the corrosive effect of the water in the exhaust, the need to use distilled water to avoid clogging of the steam producer, some insurance that no droplets enter the turbine (big ouchie at 120k rpm). Also I don't think that just some copper line wrapped around the exhaust would be sufficient to produce real lots of steam that would be necessary to produce that much more of a volume flow to make the turbine work sinificantly harder. Maybe with an heat exchanger in the downpipe? (Some of the street cleaning trucks over here use this to heat up the water)

I think the idea should be followed, but the energy requirements and flow rates should be calculated.

AlpineRAM

HOHN

Water injection has been used on jet engines as a band-aid for years. It doesn't do anything for horsepower. What it does is increase the thrust of the engines by increasing the MASS of the flowstream coming from the back of the jet engine.

What happens if you increase the mass of the gas in the turbine housing?

First, as Alpine said, the engine is going to have to work harder on the exhaust stroke. Thus, more pumping losses and less efficiency. He's also right about a loss of enthalpy.

It's possible that steam injection would make the turbo more efficient at the cost of engine efficiency.

Also, keep in mind that it's only worthwhile if it raises boost pressure MORE than it raises exhaust back (or drive) pressure. THAT'S a step in the right direction.

Justin

Steve Roseman

Doesn't hurt to ask when you have an idea, but I don't think this one will fly.
Even if you could produce enough steam, more than likely you would reduce the exhaust temperature enough to adversely effect your boost levels. Kind of like placing the turbo further from the manifold, less boost and more lag.
You wouldn't have any effect on the egts where it matters most, in the cylinder.
If you did happen to get a slug of water hitting the exhaust turbine, poof!

thumper 549

But- the thing to remember is is water is the most expandable thing known ,thats why steam engs work so well .......so lets not quit to early here.........esp if there was direct inj. of h20 who knows????????????????

TexasHardcore

Thanks for the replies...alot of good points have come up.

I was wondering about the fact that heat=power...so by adding steam, it might actually rob some of the exhaust pressure since it'd lower the temperatures.

I'm going to keep researching this whole thing and see about setting up a injection system on an old Ford 2.3 Liter Turbo....

Keep up the comments, ideas, & suggestions...it's the smart bastids out there like you guys who help us dumb guys get things straight, lol.