Timing changes with blending

Single Tank WVO systems and blending SVO WVO to thin it.

Moderators: SunWizard, coachgeo

Postby SunWizard » Mon Dec 01, 2008 9:39 pm

coachgeo wrote:
SunWizard wrote:...Is there some part of those 2 factors that you disagree with? (if thats what you mean by don't add up?)
not sure the VO/Diesel seperate out. My guess is they stay combined while the petrol seperates out and ignites seperately.

What leads you to think that RUG would separate out and D2 doesn't? I don't think any parts separate out, they simply ignite when they reach their auto-ignition temp. This is why D2 is first, RUG next, then VO. The more of the higher AIT parts (RUG and VO), the more retarded the timing compared to D2.

I have seen some good research on this that stated the cetane of a blend is proportional to the % of the components cetane. I will see if I can find it again. Edit -here it is, very good and complex info about cetane:
www.nrel.gov/vehiclesandfuels/pdfs/sr368051.pdf
This would show that there are not 2 flame fronts, since if that worked, a small amount of a low AIT like D2 would be all thats needed to start the entire combustion and cetane wouldn't be affected by adding large amounts of VO. Cetane is directly related to AIT.
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Postby coachgeo » Mon Dec 01, 2008 10:01 pm

SunWizard wrote:...What leads you to think that RUG would separate out and D2 doesn't? .
Seperate out is probably not the right term.

But if you think about it...... you have two cetane "oils" One can see how they might could blend together to create one ignition point based on the math of the two cetane properties.

The octane component...... RUG... being ignited seperately. Could it ignite NOT by auto igntion but by something acting as the spark of a spark plug.

Im pretty sure I read your other post your refering to that seems to counter this idea. Please do include a link again to it though for others to view.

If I recall right that test paper was done at a theoretical level using calculations and associative test equipment that theoretically simulates combustion or some such thing. Another words it was not calculated via actual combustion results within a diesel engine. I could be wrong though.

Anyone got any other possible theory why RUG blends seem to work?

Sun we already know you dont and have data to back up your thought process of RUG blends. But lets not cutt off those who want to attempt to disprove it those ideas by going the opposit direction and trying to theorize.... maybe later test to see why RUG blends DO work.
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Postby SunWizard » Mon Dec 01, 2008 10:03 pm

I remember Kugel's post about this. What he was referring to was the physical ignition delay PID, which is due to viscosity. The flaw in that logic is that PID is a very small factor compared to the chemical ignition delay, which is determined by AIT. See the link I gave in the above post for a full complex explanation of that.

I think the problem that leads to bad conclusions is because nearly all the posts say "I got better power with X blend." but they don't say % of parts and they don't say compared to what? And MPG claims are drowned out by testing errors.
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Postby coachgeo » Mon Dec 01, 2008 10:16 pm

SunWizard wrote:... This would show that there are not 2 flame fronts, since if that worked, a small amount of a low AIT like D2 would be all thats needed to start the entire combustion and cetane wouldn't be affected by adding large amounts of VO. Cetane is directly related to AIT.
Yes and no. Are you not talking fuel oils that are all on the cetane scale? What if in a blend you get two subsets you might say.

All the cetane things (diesel, veg, turps, Diesel Clean etc) being one subset with its combined cetane and AIT mathmatical stuff coming into play during combustion

whileee...... in the meantime in the blends we are discussing you end up with.....

alll the octane things (RUG, Naptha etc) being another subset with its combined octane and AIT mathmatical stuff coming into play "seperately"

so its like the math principle of

O + A = O + A during combustion ....... NOT O + A = OA during combustion.


Now granted.... Im sure there is a breaking point where too much octane components blended into other Cetane components will drown out the cetane in some way and create poor combustion in a diesel compression engine. Drown is a bad word here.... I dont mean it literally.
Last edited by coachgeo on Mon Dec 01, 2008 10:19 pm, edited 1 time in total.
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Postby SunWizard » Mon Dec 01, 2008 10:18 pm

coachgeo wrote:Sun we already know you dont and have data to back up your thought process of RUG blends. But lets not cutt off those who want to attempt to disprove it those ideas by going the opposit direction and trying to theorize.... maybe later test to see why RUG blends DO work.

That is wrong, I have data from my own tests of RUG blends in my 300D which I have referred to here and other threads. This is far better than any math. RUG blends do work, and I use them, they just have the issues discussed in the RUG thread.
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Postby coachgeo » Mon Dec 01, 2008 10:32 pm

SunWizard wrote:..That is wrong, I have data from my own tests of RUG blends in my 300D which I have referred to here and other threads. RUG blends do work, and I use them, they just have the issues discussed in the RUG thread.
Should we interprolate your one set of data to all other RUG blends and engines?

My concern is you are still and before in RoverHybrids thread rather stong in your statements. It seems to cary a tone that "completely" discounts those who say RUG blends seems to work even better than "just working". Your tone; at least to me comes across as discouraging exploration of why RUG blends might work better than you think.

This has been the common tone for yearssssss... way back with Kugel first realy explored why it worked it and tried to figure out why it worked so well for him. (2003, 2004?) Your not the only one so dont feel singled out. That's just been the pattern. Someone comes around every few years that want to explore the notion that RUG blends work "real well" and then others jump it and discount it emphatically and discourage any furhter exploration. Then it gets dropped.

Kugel left the whole discussion thing cause it worked DAMN GOOD and he seemed to have good explanations why..... but after so much flack about how he must be wrong....... he just left. That and an overseas job... but still... he's still happly tooling along on an RUG blend that works remarably well.... he just stays off the boards. Pretty much gone since 2005

Same thing that use to happen about WVO fuel use in general, luckly that spell was mostly broke though it still happens.... same thing that use to happen to folk wanting to explore using diesel engine oil centrifuges (diesel craft type ) as WVO centrifuges etc. . Lucly that one got nipped in the bud and you explorated it anyway and brought us to where we are today in that catagory. By the way thank you for that Sun.
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Postby SunWizard » Tue Dec 02, 2008 12:05 am

coachgeo wrote:Should we interprolate your one set of data to all other RUG blends and engines?

Of course not and I never said anything like that.

The process of understanding how a RUG blend works is what these discussions are about, and I spend lots of time doing research, testing it myself, and detailed posts about it to help anyone who is blending. This is the opposite of "completely discounting". The point is being aware of the issues with any blend so you can do it safely and not shorten engine life.

When someone jumps into a post claiming RUG blending is better for every aspect (power, MPG, emissions) with no data, is when I will come in to add the awareness of issues and question those statements I think are false as I did here. Too bad we are likely to get many posts hijacked into the same RUG debate (without new data) now that Jeffrey is back, as this one has been.
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Postby SunWizard » Tue Dec 02, 2008 12:23 am

coachgeo wrote:The octane component...... RUG... being ignited seperately. Could it ignite NOT by auto igntion but by something acting as the spark of a spark plug.

No it could not. Auto ignition is how it works in a diesel, and the delay between injection and ignition is very short. People get the wrong notion that RUG will ignite quicker since its more volatile and there can be pre-ignition (before the spark) in gas. This only happens because the fuel is in the combustion chamber the entire compression stroke in a gas engine, which can heat it up to the auto-ignition temp before the spark. This can't happen in a diesel. This is also why RUG is required to have a high AIT temp, which is one aspect that makes it worse for blending than D2.

The viscosity of RUG is lower than D2 which counteracts the AIT drawback, at least for small 5-10% amounts.
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Postby coachgeo » Tue Dec 02, 2008 1:25 am

well hopefully our discusion has brought up thimk topics and WILL stimulate actual testing.

I agree with you. Anyone willing to dive into the RUG blending thing needs to go those extra stops that keep getting avoided.

Testing testing testing.

Pretty much the same path that Biodiesel has gone thru... talk is cheap but prove your talk..... WVO is still going thru this.... etc.

Will just have to see if we can get folk to cary the ball and not just the torch.

LOL... enough cleteau's
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Postby John Galt » Tue Dec 02, 2008 2:12 am

@#$*&^%$!!!
Last edited by John Galt on Thu Dec 04, 2008 8:56 pm, edited 1 time in total.
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Postby zoochy » Tue Dec 02, 2008 5:10 am

John, You are a guilty as the rest of us in as far as still wanting to talk about it. It’s an enigma. It works, but why or how?

As far as biocowboy being “Jeffrey Brooks”, I hope not, Biocowboy writes better apart from the one post w/ too many links. Providing multiple links is a shortcut to thinking.

Assuming that there could conceivably be two flame fronts (or at least an initial flame front) solves the mystery as to why blending with RUG works so well. Auto ignition temperatures are only relevant when there is no spark or flame. As soon as one fraction of the blend combusts, auto ignition temps become irrelevant as the entire blend will go POOF due to the presence of the flame. Although, Sunwizard’s link essentially dispels the idea of 2 flame fronts, unfortunately it’s not very convincing and written with much, much reserve.

The idea that blending with fluids that have a higher auto ignition temperature than diesel will produce a fuel that has a low cetane, can only be tested by actually measuring the cetane of the blend. Cetane Number is a measure and cannot be accurately linearly interpolated when blending fuels with dissimilar values.

Unfortunately the only way this discussion will be put to rest is if someone has access to a “combustion bomb or single cylinder combustion test engine” and posts/publishes some results. I wish I wasn’t so busy with other things and had a proper shop to tinker, I think building such a device would make a great little winter project…
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Postby SunWizard » Tue Dec 02, 2008 9:52 am

zoochy wrote:Unfortunately the only way this discussion will be put to rest is if someone has access to a “combustion bomb or single cylinder combustion test engine” and posts/publishes some results.

Putting your car on a dyno would be easier since they are readily available in most towns. Then try different blends under loads and see the difference in power. That is a good indicator of cetane and overall combustion efficiency. A dyno could also be used to optimize your timing for the blend you are running, which might even be able to compensate for any power loss caused by RUG or VO compared to D2. People have done dyno testing and have found that advancing by 3-4 degrees helps power greatly when running VO. This is because they are compensating for VO's higher AIT which retards timing (back to the thread subject.) This is further hard data and testing already done that points to the AIT and timing being an important factor in VO use.

An emissions test is not a good indicator, since HC hydrocarbon emissions are improved hugely with blends of VO and bio compared to D2. HC is what is measured by opacity. And often emissions are improved when your timing (and MPG and power) is not optimized.
Last edited by SunWizard on Tue Dec 02, 2008 10:28 am, edited 3 times in total.
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Postby SunWizard » Tue Dec 02, 2008 9:59 am

John Galt wrote:Quite a few people seem to be using gasoline or naphtha mixed with VO and other solvents if we can believe what's posted on this discussion:
http://www.burnveg.com/forum/viewtopic.php?t=267

I count 5 in that thread, which I wouldn't call quite a few. You can find quite a few if you scour many infopop posts.
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Postby John Galt » Tue Dec 02, 2008 2:18 pm

@#$*&^%$!!!
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Postby SunWizard » Tue Dec 02, 2008 2:48 pm

John Galt wrote:
often emissions are improved when your timing (and MPG and power) is not optimized.

I don't buy that; it makes no sense. If HC emissions are reduced one is getting the best MPG. i.e. less fuel out the tailpipe.

Not true, for example you could have a reduction of 30% in HC simply because VO always reduces HC, and unless you did timing adjustments and then saw that was the max. reduction you got, you wouldn't know if its the best. Did you do this? Maybe you could have got 50% reduction. If you did this, what timing was best?

Was your emissions test on a dyno under load? If so, what load? If not then I question its value since idle and no load are far different than when driving.
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