Tomorrow I'll finish grabbing a second set of manifold to play with, I'll be installing boost/intake temp/EGT/EGP sensors along with rebuilding the turbo.

As part of an independent study I am working with retrofitting existing diesels to use ethanol air stream injection to reduce diesel consumption/increase performance(in bursts). Why ethanol? Another student is working on a system for farms to make ethanol from waste silage, and this will tie in with it.



As for performance; why couldn't you add a nozzle to squirt alcohol/water into the exhaust PRE-turbo? This could in theory causing it to spool up on-demand giving you more off the line. Match that with injection in the air stream, and in theory you've got a nice little boost.

I was thinking of adding either one nozzle at the EGR port, or 5 evenly spaced along the manifold. I'll probably do both and record measurements, they call it a study for a reason, right?


As for fuel economy, we are assuming that the alcohol is homebrewed and around $0.75/gal worst case scenario


I need more holes in my project, so let loose with any/all comments!

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$60 OM617 Blank Exhaust Flanges
$110 OM606 Blank Exhaust Flanges
No merc at the moment

Because its horribly polluting to inject raw fuel into the exhaust. Injecting a cold liquid into a hot cast iron manifold is a great way to crack it.

Sounds like Simpler≠Better any more.

Ah, I kinda forgot about that. I guess I'll have to make a titanium one/buck up and do the VGT route for low end boost.

In my book, it counts as simple until a computer controls my engine(Long live Rube Goldberg!)

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$60 OM617 Blank Exhaust Flanges
$110 OM606 Blank Exhaust Flanges
No merc at the moment

I have to say I can't quite figure out what water/alcohol pre hot side turbo injection would do to increase performance, unless you are expecting spontaneous ignition. You might achieve that by injecting straight alcohol in sufficient quantities at moderate engine loads. As far as providing an economical performance boost I doubt it. It might be fun though. ethanol combustion is very clean,
C2H5OH + 3O2 → 2CO2 + 3H2O + heat
It might well reduce NOx emissions in diesel exhaust though that is already fairly low. Simple can often be better and more reliable. Personal attacks during a discussion often only expose ones limited thinking.

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Bob D.
Parrish, FL
1 SDL, 1 D, 1 TD, 1 Mog

It would make tons more sense to me to throw it in before where it can be burned. There really couldn't be any fuel economy improvements since your talking about the exhaust side by cooling it assuming it's not excessive would actually slow the turbine and cause less work to be done on the other end. Most turbo's do there best when pushed towards there max. safe limits cause they grow and fit more closely most one's i've seen.

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2004 Infiniti G35 3.5L 6mt Coupe 73K miles 25.6mpg ytd
2001 Green Audi TT 225 AWD Roadster 71K 6sp 30.9mpg >>STOLEN<<
1982 300D Turbo 231K 120hp? 28.1mpg YTD

Exactly. The water would cool the hot exhaust gasses, significantly reducing the exhaust volume and the turbo's efficiency.

I might not have been clear before: I would like to do alcohol injection into the air intake, with the nozzle(s) attached to the pressurized manifold(so not to risk damaging the turbo's blades)

The secondary injection part would be(theoretically) into the exhaust stream, pre turbo. The theory is that the exhaust gas is hot enough to ignite the alcohol, and create more pressure fueling the turbo. I see how it could cause damage to the manifold if too much was injected, or if it wasn't properly misted (I could see soot gumming up a nozzle pretty quick)

The idea stemmed from hearing about some race cars where they would drip gas into the manifold to maintain boost while off-throttle.

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$60 OM617 Blank Exhaust Flanges
$110 OM606 Blank Exhaust Flanges
No merc at the moment

On the intake side, you may be able to gain some power/efficiency by adding alcohol if it is properly vaporized, similar to adding propane. You would have to check the flash point and make sure it's not too high otherwise it can be pretty hard on the engine.

The downside of this is that the cost of the suplementary fuel usually offsets the gain in power/effeciency.

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-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250

Yeah, but we're assuming that the supplementary fuel is being homebrewed from waste silage, etc.

Lets say you're supplying 20% on the go pedal; how much ethanol could you add to the intake before the octane raised to the point of non-combustion?

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$60 OM617 Blank Exhaust Flanges
$110 OM606 Blank Exhaust Flanges
No merc at the moment

Thats a trial and error question, there is no answer.

Alcohol/methanol injection is known to work, just not very well in street applications (Drag racing and towing are different). I had a 50/50 water/methanol injection system pumping 300cc/min and I only gained 2hp at the wheels (dyno tested, there is a thread on it) and no significant change in MPG. I abandoned it since it was more hassle than it was worth.

But did it lower the egt's?

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Have you ever noticed that anybody driving slower than you is an idiot, and anyone going faster than you is a maniac?

As long as they would add one additional commandment for you to keep thy religion to thyself.
George Carlin (Wonder where he is now..)

1981 240d (engine donor 1983 240d) recently rebuilt engine hurray! - No more.. fought a tree and the tree won.

pearl black 1983 240d 4speed (Converted!@$$%) atleast the tranny was rebuilt.

I know this is outside your project range, but what would be great is a direct injection water system that would inject late in the combustion stage. This would cool the exhaust gas and since the expansion coefficient for water is so large, should gain some torque. I'm pretty sure this was done on earlier diesels, not sure why it was abandoned.

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For Sale: 1982 MB 300TD
1995 Chevrolet Suburban 6.5TD

Sold: 1980 IH Scout Traveler- Nissan SD33T Diesel

I would wonder if cooling the combustion environment before the exhaust valve opened would cause a vacuum to form and rob power/break things?

I think this direct H20 injection thing might make more sense if there was an extra compression stroke added specifically for the water injection event, in which case the glowplug holes might be a good place to stick injectors for a common-rail water setup.. run the cam at 1/3 engine speed instead of 1/2... read: Crower 6-stroke... speaking of which, does that thing even work?

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99 E300 Turbodiesel 100k

Here's a link to a paper concerning Water Injection (WI). http://homepages.cae.wisc.edu/~rutland/research.dir/NOx_water/2000-01-2938.pdf These researchers were primarily concerned with reducing emissions, but found that fuel consumption was reduced in some cases (increased in others). Its been a while since I read it, but I'm pretty sure that the water injection timing was not altered (went in right after fuel). I think that this would be a huge factor. Yes, WI would necessarily reduce the temperature, but the expansion ratio of water is huge. So, for limited amount of water you would increase post combustion pressure while reducing NOX production. Too much water will of course reduce pressures.

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For Sale: 1982 MB 300TD
1995 Chevrolet Suburban 6.5TD

Sold: 1980 IH Scout Traveler- Nissan SD33T Diesel