Study on the effect of 2-EHN on diesel combusion

[Tony]

Found this:

http://www.fragging.de/2EHN.pdf

From the summary:

The results indicate that the
primary effect of the additive is to increase the
radical-pool formation very early in the autoignition
period, leading to a shorter overall autoignition
period for a diesel spray. This effect is
greatest at lower temperature-density conditions,
corresponding to low-load and start-up conditions
in a diesel engine, and becomes negligible at the
highest temperature-density conditions examined.
The investigation of the effects of the
additive on other aspects of the spray such as the
liquid length, the spreading angle (i.e., mixing ),
and the combustion lift-off conclusively show that
the additive does not affect physical processes in
the spray, or combustion processes once the
ignition phase is complete.

So my feeling that it only improves short, cold started journeys seems to be borne out by this.

[neisel]

It would be handy to have a definitive 'additives' page which explained authoritatively what different additives actually do.

I use 2-EHN in BD because I thought it added more bang, like higher octane fuel does for an older, high performance petrol engine.

Recently I was given a couple of litres of Acetone. I thought it did something to the BD which helped in more evenly spraying the fuel out of the injectors but reading up here & on the other side it appears to do (or at least people believe it does) everything from aiding cold starts, raising the cetane number, increasing the horsepower, increasing fuel economy & keeping bits nice & shiny. 

[Tony]

I wasn't convinced on acetone, but may be wrong - found these studies on the subject:

http://www.biofueljournal.com/pdf_4748_969fac4c4db552da9c2a7ce783c4e06f.html
http://www.irjes.com/Papers/vol1-issue2/Version%202/B121116.pdf
http://www.iosrjournals.org/iosr-jmce/papers/RDME-Volume6/RDME-54.pdf

A quick skim suggests that acetone does help as a biodiesel stabiliser, and may improve efficiency - but only if injection timing is also advanced.

[Jamesrl]

If 2ehn doesn't increase mpg how would you explain why my car does more mpg with it than without it?

[Julian]

I should really give it a better test than I have, but I've tried this stuff and I have to say I didn't really notice any difference to the Disco's performance, mileage, or reluctance to start.

That said, given its age, condition and mileage, there's probably little that would improve any of those parameters!

[Jamesrl]

I always  put 25lt at a time into the tank and quite often zero the on board compoota to just to check the consumption and deliberately use the occasional 25ltr without 2ehn to compare.

That's how I know it works for me.

[Julian]

25 ltrs!!!

That stuff's expensive isn't it?

[Jamesrl]

Yep, but I once out accelerated a Buggati Varon on the M2 using the stuff, so there.

[greasemonkey]

It makes sense.
Given that it appears to have such a narrow and specific effect, then it would make sense that folks with different engines, and driving styles, may have a different experience of it.

Just sort of thinking aloud here, but if it mainly effects auto ignition, then maybe those who drive around with larger, turbo, or NA engines, hardly revving it, could find the greatest benefit, especially as regards MPG.
Where as those who warm her up and drive off down motorway won't really notice much, because the auto ignition part of the cycle is already well taken care of.

Pottering around on low rev, anything that helps the fuel go bang has got to be good. If the engine is running at three quarter rev, all being equal, the fuel is going to go bang without a problem, is my reasoning.

Being as I fall into the category of big engine and little rev, maybe I ought to try it.

James, am I right in thinking you run Picassos? What sort of MPG are you getting?

I also have one. It's not been introduced to home brew yet.
Its the 2 litre turbo, I'm getting about 38MPG on tax juice. I think there is something wrong with it. All I hear about them is how economical they are. It's not much better than my Transit......

[Glycer-rides]

I always  put 25lt at a time into the tank and quite often zero the on board compoota to just to check the consumption and deliberately use the occasional 25ltr without 2ehn to compare.

That's how I know it works for me.

What % improvement do you get, Jim?

[Jamesrl]

I always  put 25lt at a time into the tank and quite often zero the on board compoota to just to check the consumption and deliberately use the occasional 25ltr without 2ehn to compare.

That's how I know it works for me.

What % improvement do you get, Jim?

Depending on how I drive the ol' girl  but 10% is not impossible,  she's averaging 47+ with a lot of cold short trips and returns mid 50's on a run up to the boat.

[Tony]

That's not bad.  The Passat is supposed to get 60mpg on long runs, but I drive it like I stole it so usually get 45, and less in the city.

[greasemonkey]

I think I have a problem then. It doesn't seem to run quite right either, sort of feels held back, and judders on a steady throttle. It's a bit of a job to tell, coz it's so different to what I've been used to for the last 7 years.
Not top of the agenda anyway, but I'll get to it sometime.

[Jamesrl]

Is it a 110 or 90hp?

[Jamesrl]

There's something you could try that's reasonably easy.

Remove all the injectors, be VERY careful removing the spill back spring clips as they have a habit of disappearing without trace.

On the business end there's a nipple that gets coked up, I used a modelling knife to scrape the surface clean. Believe it or not there are 4 holes 90° apart 2/3 the way down the nipple, bet you can't see'm. Anyway once I did mine which had done 120k the performace returned to the day I bought it.

There is one other small thing that happened when I replaced the exhaust centre pipe, the center of the catalyst fell out giving me a straight through gas flow, I was very disappointed at losing the cat matrix, as would anyone be.