quote:

Then measure the difference between the figures for VO at 75C and 135C (Its zero difference at most points on the graph.) Then take that difference and project it to the scale on the left side. This is the same way you read any graph to read amounts from it.

I though that was the chart you referred to when you claimed

quote:

Here is the best scientific study I have seen that compared D2 and VO at temps of 30C (86F), 75C (167F), and 135C (275F), see post#3:
http://www.frybrid.com/forum/showthread.php?t=3596

The results show very tiny (<2%) improvements in Fuel consumption, thermal efficiency, and smoke opacity when going from 167F to 275F. EGT and NOX emissions were worse at the higher temp.

Since so many of the results are at odds with every other study I have seen I have to conclude that this is the ONLY study you have access to.

But you claim

quote:

No I have access to a large variety of studies.

quote:

That is hard to believe.
Please provide links to the other studies that you can access.

Especially any that show results similar to the one you think is "the best".

quote:

What is the amount of improvement shown in ACREVO (or any other study) in power or mileage when going from 160-230F+ VO temp?

Am am not aware of any public study which studied these parameters.
However power and mileage are both dependent on combustion efficiency. This is on of the things which was studies in the ACEREVO study..and the conclusions are clearly stated. Combustion of VO is dependent on how finely the fuel is dispersed and penetration. In engines with injector nozzles designed for diesel fuel the optimum dispersion and penetration of VO is when its viscosity matches diesel fuels viscosity.

This also results in the lowest deposition of carbon due to incomplete combustion of VO fuel.

quote:

Originally posted by danalinscott:

quote:

What is the amount of improvement shown in ACREVO (or any other study) in power or mileage when going from 160-230F+ VO temp?

Am am not aware of any public study which studied these parameters.
However power and mileage are both dependent on combustion efficiency.

Still power and mileage are the figures that matter most when comparing things. They are relatively easy to measure in a controlled study. Thats why in the automotive industry almost every new feature or tuning is tested on a dyno. Yet ACREVO didn't do this, so we are left with only the 1 study I linked (Pugazhvadivu 2005) where they measured what matters most.

1 study that used a dyno (Pugazhvadivu 2005) and 1 that used photography of injection in free air (ACREVO 2001) isn't enough data points to justify everyone changing to injector line heaters. So I repeat what I said on page 1: "I don't think those tiny improvements justify the extra cost, complexity, and risk of other failures (such as damaging electronic injectors, or problems due to higher EGTs) related to the higher temps.

The conservative approach I follow says that since most VO users are operating just fine near 170F, that much more testing is needed before recommending people raise that to 230F and higher."

I can't help but notice that you didn't link to any studies.

Why do you beleieve that power and mileage are more important than combustion efficiency when comparing "things"? What do you mean by "things"..specifically.

Dynometers are mainly used to LOAD an engine in testing so the other parameters being measured are applicable. "Things" such as combustion efficiency.

You really haven't even read the links to info I provided...have you?
Only one is a link to the Acrevo study.

In fact it appears that you have not read the study you cite. HP was not measured. like other studies the dyno was only used to LOAD the test engine.

Once again you appear to be assuming far too much for your conclusions to have much validity.

quote:

Originally posted by SunWizard:

quote:

Originally posted by danalinscott:

quote:

What is the amount of improvement shown in ACREVO (or any other study) in power or mileage when going from 160-230F+ VO temp?

Am am not aware of any public study which studied these parameters.
However power and mileage are both dependent on combustion efficiency.

Still power and mileage are the figures that matter most when comparing things. They are relatively easy to measure in a controlled study. Thats why in the automotive industry almost every new feature or tuning is tested on a dyno. Yet ACREVO didn't do this, so we are left with only the 1 study I linked (Pugazhvadivu 2005) where they measured what matters most.

1 study that used a dyno (Pugazhvadivu 2005) and 1 that used photography of injection in free air (ACREVO 2001) isn't enough data points to justify everyone changing to injector line heaters. So I repeat what I said on page 1: "I don't think those tiny improvements justify the extra cost, complexity, and risk of other failures (such as damaging electronic injectors, or problems due to higher EGTs) related to the higher temps.

, that much more testing is needed before recommending people raise that to 230F and higher."

quote:

Originally posted by DCS:

quote:

Originally posted by john galt:
DCS, right you are again. I wonder why the individual who complains so much about how poorly moderated and organized this forum is, doesn't just take these self serving discussions to THIS FORUM where they could have complete control over what gets posted?

I can only speculate John that having complete control over what was posted didn't give said individual the satisfaction they are craving. It seems to me that the real desire they harbor is a need to incite argument not discussion as there is evidence they have tried playing Forum God and that didn't satisfy their irrational cravings.


Examination of the site you linked to shows that in over 3 years, the forum has only attracted a total of 369 members at time of writing this post.
Given the popularity of Veg oil topic, the media attention it has received and the size of other forums on this subject, I would have to call this forum a rather dismal failure.

If one looks a little deeper at the site statistics,( Plantoil/diesel conversion basics Statistics
Threads: 314, Posts: 1,221, Members: 369 -) one can see that out of the total 1221 posts made, 680 of them are by one single person. No prizes for guessing it's the moderator. Roll Eyes
Further rendering this forum more of a Soap Box than a place of discussion, is the fact that a search of the members list reveals many of the members have never posted at all, about 95% have never posted more than 5 times and I could only find one member in a cursory scan that had reached a post tally of 20 contributions. Obviously people signing up to that forum don't last long or there are only a few people who will agree with everything the moderator of the site puts forward Which could possibly be an unwritten requirement of participation or ones comments actually making an appearance on the site at all.

The link to the numbers Data for those that believe nothing without one, is here: http://voconversionbasics.webs...com/register/members

Clearly the stats of this site show that to this individual, control isn't enough. They also have a craving for an audience to argue with and force their inflexible fabrications of the truth and reality down as many peoples throats as possible. Perhaps it was that very behavior that has made their own forum the waste of server space it clearly is?

It would further the cause of veg fuels and this particular forum no end if this person could contain themselves to their own desolate backwood corner of Cyberspace which they no doubt set up with hereto unrealized disillusions of greatness and worship from the great unwashed ( and dried) but clearly they have got tired of preaching to themselves there and have ventured further afield in order to maximize the amount of people they can annoy, argue with and make themselves look foolish in front of.


****

Well it's nice to see we agree on something Dana.
You didn't even attempt to put up an excuse or reply to what I said here so obviously you agree with it as conclusively demonstrated by the fact your not arguing with any of it. I guess someone was finally able to put up some links to facts and figures you not only agreed with but couldn't argue with either.

It is unfortunate though that when people are able to satisfy your demands for links and supporting evidence of their point, you instantly dismiss and refuse to accept it with some predictable contorted excuse but when anyone questions the evidence you put forward, your information is unfailingly reliable and accurate without question!

Perhaps you could tell us how we can tell the studies and info that is flawed and be able to spot the unquestionably accurate info the same way as you always can? Would it just be as simple as asking your if you think it's right and if you believe it is we know it to be as reliable as the word of god.... Dana the veg god I mean.
He is more perfect than the other one it seems.

I'd be interested to also hear your answer to Johns question about why you come here and post at all when you take such exception to so many things and people on the site when you have your own site, where as far as I can tell, people meet all the behavioral requirements you lament in nearly every post you make here? I mean having made Heaven, I don't think it likely that God choses to hang out in Hell, but that is exactly what you seem to do.

Logic would dictate if your complaints weren't just another ruse to discredit others with ideas other than your own when there isn't the supporting evidence you make such demands of from others to support our own rebuttals, why you wouldn't stay away and confine your posting to the place that is your own self created forum Nirvana?

I mean according to you, people here ( myself and others) have an agenda to derail discussion that furthers veg development. I never even realized that!
I can't ever recall looking through the posts here and thinking" Oh! There is a discussion that is going to make the use of veg better, I'll have to post something that derails it so people will have to do the same thing they are doing now and not discover these tings that I want kept secret"
That is what you are saying is the thought process of myself and others right?

OTOH, I KNOW I look through the posts and think, " Hmm, Dana is back again pushing his own single minded ideas and spouting a load of crap that precious few, if anyone agrees with and contorting the facts to suit his own agenda of self elevation and ego stroking by refusing to admit that there may be more to the FACTS than his single, narrow minded ideas will allow for and in the process creating threads that would lead others early on in their veg learning come away with a completely distorted or patently wrong idea of veg use".
I have to admit to thinking that virtually every time I read through your posts!

I guess if that is trying to derail the advancement of Veg technology, then I am guilty.
I thought that keeping infomation factual, unbiased and honest was in fact advancing the veg cause.
Clearly you think that's wrong.

Posers talk about VO based fuels, realists actually use it in their personal vehicles.

quote:

You didn't even attempt to put up an excuse or reply to what I said here so obviously you agree

Yeah...that must be it.

Start a discussion on that subject if you want me to reply.
You have hijacked this one quite enough.

quote:

Originally posted by danalinscott:
I can't help but notice that you didn't link to any studies.

Yes thats one of my main points, there are only 2 studies we can find of heating VO near 230F. Even though I have access to hundreds of studies of VO. This serious lack of study makes it a real stretch to reach a useful conclusion.

quote:

Why do you beleieve that power and mileage are more important than combustion efficiency when comparing "things"? What do you mean by "things"..specifically.

Because power and mileage are the relevant figures that will improve with combustion efficiency. Because we don't have any better method to judge improvements. The photographic study of the injectors in free air in ACREVO is far too subjective, yet this is all you are basing your conclusion upon? Can you tell me the amount of improvement in combustion efficiency they got when they raised the VO temp from 170 to 230F?

The amount of improvement is how we could decide whether the change in question is worth doing. "Things" are most aspects of engine or fuel or tuning changes which are all easily compared with a dyno. "things" like raising the VO temp from 170 to 230F is the relevant one for this thread.

quote:

Dynometers are mainly used to LOAD an engine in testing so the other parameters being measured are applicable. "Things" such as combustion efficiency.

The dyno measures the power output across the entire RPM range, and that is what is compared to decide the amount of improvement for most comparisons except emissions. What method do you propose to best measure the amount of improvement in combustion efficiency?

quote:

You really haven't even read the links to info I provided...have you?
Only one is a link to the Acrevo study.

Yes I have read them many times.

quote:

In fact it appears that you have not read the study you cite. HP was not measured. like other studies the dyno was only used to LOAD the test engine.

Yes power was measured, that's how graphs for thermal efficiency are always produced, including the one I linked. See the X axis on each of the graphs, its labeled "brake power kW" which equals power! Thermal eff. is a simple formula derived from HP and fuel consumption and fuel BTU.

A graph of RPM versus power is simpler and more commonly used in the auto industry. This is what I am proposing to some VO researchers I am working with.

quote:

Once again you appear to be assuming far too much for your conclusions to have much validity.

My conclusion is that you don't have enough data with 1 study. What conclusions are you questioning in such a vague way?

quote:

I have access to hundreds of studies of VO.

Really..yet you cannot provide a link to any?
(Redacted reports like the charts you linked to really do not count)

quote:

The dyno measures the power output across the entire RPM range, and that is what is compared to decide the amount of improvement for most comparisons except emissions. What method do you propose to best measure the amount of improvement in combustion efficiency?

Power output does not indicate combustion efficiency.
Fuel usage compared to total power produced does.

The most useful test I have been able to suggest so far was discussed in detail several years ago on this forum. By logging the EGTs and GPH of actual vehicles repeatedly travelling over the same road course on both petrodiesel and WVO heated to different pre-injection temps one can get a fairly good idea of how much of the energy in wvo is actually being converted to power.

quote:

My conclusion is that you don't have enough data with 1 study. What conclusions are you questioning in such a vague way?

I agree that one study by itself would not be enough to reach any strong conclusions.
However I have not used a single study to reach any conclusions..you on the other hand appear to have reached a competeing conclusion based on a study to which you seem to only have partial access.

I have provided links to several supporting studies.
You appear to not have bothered to read them.

I gaurrantee that if YOU post links to studies that provide counter evidence to ANY conclusion I have reached I will read them.

This message has been edited. Last edited by: danalinscott,

May I kindly ask for your opinion, Dana

http://www.fachdokumente.lubw....5002SBer.pdf&FIS=203

BMW Fan

quote:

Originally posted by BMW Fan:
May I kindly ask for your opinion, Dana

http://www.fachdokumente.lubw....5002SBer.pdf&FIS=203

BMW Fan

Certainly...
It is my opinion that the document you sent me is a report on the use of VO as a fuel in diesel engines.

Unfortunately it is in German and I do not read German.

Do you have access to the report in English?

quote:

Do you have access to the report in English?

Dana,

no I haven’t.
A lot of researchers have access and knowledge how to use a “ translator “ ?
You are missing a lot of good and new research and information
The paper includes studies relevant for IDI and Common rail and allows comparison.
The study was done in 2007.

BMW Fan

quote:

Originally posted by BMW Fan:

quote:

Do you have access to the report in English?

Dana,

no I haven’t.
A lot of researchers have access and knowledge how to use a “ translator “ ?
You are missing a lot of good and new research and information
The paper includes studies relevant for IDI and Common rail and allows comparison.
The study was done in 2007.

BMW Fan

I understand the study was done in June of 2007.
And I understand that I can use a "translator program" such as Babel Fish to roughly translate it from German to English.

Unfortunately I also understand that such programs translate technical terms very poorly and do not trust the information I can glean from a roughly translated version. I prefer to obtain human translated versions which generally contain much more trustworthy information.


And in this particular case the copy you provided a link to is "locked" so even copying the text (so it can be pasted into Babel Fish for translation) is not possible. I would have to retype the entire document into Babel Fish in order to even get a rough translation.

If you can provide the name of the document you linked to in English I may be able to find a copy which has already been translated into English.

Edit: Is the name "Investigation of a New Injection Strategy for Simultaneous Soot and NOx Reduction in a Diesel Engine with Direct Injection"

If so I have read the summary and do not see how this paper directly applies to this discussion.

The issue of cetane was raised.

quote:

Also important as someone just pointed out is the cetane value of the fuel, which we know with SVO is out of spec for most (probably all) diesel engines (45 min. is the general rule of thumb).

I recalled that cetane rating was tempertaure/viscosity related in SVO...but could not remember where I saw information that made me suspect that.

I began searching through my archive of VO info and I ran across this.

Petrodiesel is specified to have a cetane number
of at least 40. The measured cetane number
of vegetable oil ranges between 30 and 50, but all
the cooking oils common in this country have
cetane numbers below40 (seeTable 2.3), indicating
that these oils should have a longer ignition
delay than petrodiesel, and should be unacceptable
substitutes for diesel fuel.
It turns out, however, that cetane number is a poor indicator of the
actual ignition delay of heated vegetable oils. In engine studies, heated vegetable
oil consistently has a shorter ignition delay than indicated by the
measured cetane number of the oil, and indeed a shorter ignition delay
than petrodiesel. Because of a shorter ignition delay, heated vegetable oil tends to be more
thermally efficient, emit less carbonmonoxide and hydrocarbons, and produce
more NOx than petrodiesel.


Vegetable oils that are more unsaturated tend to have longer ignition delays.
Though cetane numbers do not accurately capture the ignition delay of
heated vegetable oil, the difference between cetane numbers of different
vegetable oils does reflect differences in the length of ignition delay between
those heated oils in actual engines.

cetane number, as it is defined currently, cannot
accurately capture the ignition properties of heated vegetable oil.The test
that defines a valid cetane number specifies that the test fuelmust be heated
and held at a temperature between 65° and 90°F.We know that vegetable
oil heated to that temperature will be too viscous, spray poorly, and atomize
slowly out of the injectors, and the low cetane numbers reported in the
literature are to be expected.However, if we heat the oil up to 160°F ,we are
not following the defined protocol, and therefore our result, while potentially
very useful, fails to meet the current definition of what a cetane
number is (namely the result of following the prescribed test protocol).

So as VO is heated the actual property of ignition delay changes as if the cetane number were increasing.

http://www.newsociety.com/news...r/News44/svo_ch2.pdf
From the same report:

High Temperature Reactions:
Life in the Combustion Chamber
As we’ve alluded to a number of times, when vegetable oil fuel first enters
the combustion chamber it undergoes a number of chemical changes that
affect how the oil will combust and burn.
Thermal Cracking and Polymerization
Surprising Results. Research on petroleum-derived fuels showed that
increasing the viscosity of the fuel narrowed the angle of the spray cone
and increased the penetration rate, i.e. the speed at which the spraymoved
away from the injector.40a
However, when researchers studied the spray patterns of vegetable oil
they found something very surprising.As they thinned the oil by heating
it up, the spray pattern did the opposite of what they expected.The spray
of hotter, thinner oil was narrower and had a higher penetration rate than
colder, thicker oil. This pattern held until the oil was heated to all the way
up to 293° F, the maximum test temperature (Fig. 2.11).40.b
Also surprising, the researchers found that the spray pattern of vegetable
oil was nearly identical to petrodiesel when the viscosity of the oil was still
nearly double that of the conventional
fuel. Specifically, oil heated to
285° F with a viscosity of 4.1 centistokes
looked the same as the spray
pattern of unheated petrodiesel that
had a viscosity of 2.4 centistokes at
40° C

This message has been edited. Last edited by: danalinscott,

quote:

Originally posted by danalinscott:
So as VO is heated the actual property of ignition delay changes as if the cetane number were increasing.

There are 2 contributors to ignition delay: physical ignition delay (PID) and chemical ignition delay (CID). Heating makes the PID shorter (slightly better), it does nothing to change the worse CID of VO. PID is a very small factor compared to the CID, and we get an exponentially diminishing improvement in the PID at heat above 170F. The main portion of delay, CID, is determined by Auto-ignition temp (AIT) of the fuel. The longer ignition delay of VO (=lower cetane), caused mostly by CID, can only be fully compensated for by timing advance. See this study for a full, complex explanation of this:
www.nrel.gov/vehiclesandfuels/pdfs/sr368051.pdf
From page 4:
"Early work by Yu, Uyehara, and Myers2 was able to show the separate effects of physical and chemical ignition delay. For all but very heavy fuels, the physical delay is short compared to the chemical delay."

Several detailed studies they link confirm that viscosity isn't the only fuel property to consider. They also consider other factors which affect the PID:
- density
- viscosity
- surface tension
- specific heat
- enthalpy of vaporization
- vapor pressure
- vapor diffusivity.

And mainly the CID, which varies based on AIT, which I have already mentioned earlier in this thread.

Also from that report...

quote:

When operating a compression ignition engine, a cylinder is filled with air through the intake valve. The intake valve is then shut and the motion of the piston reduces the volume of air, compressing and heating the air to approximately 600° C. At this time, liquid fuel is injected into the cylinder through a nozzle. The fuel forms a spray of droplets, which vaporize, mix with hot air, and ignite.

quote:

Hydrocarbon combustion occurs only in the gas phase. Thus, for a liquid fuel, the first steps toward ignition involve transitioning from a liquid to a gas phase. The time required for this transition is the “physical delay” in ignition and includes the amount of time required for a droplet of fuel to heat, vaporize, and mix with hot air in the cylinder.

quote:

Combustion is a sequence of chemical reactions in which the gas-phase fuel reacts with oxygen. These reactions proceed stepwise, through a mechanism involving free radicals.* For ignition to occur, the fuel must be heated to a temperature sufficient for some of the weaker bonds to break and form radicals. The finite rate of these radical forming oxidation reactions is responsible for the chemical delay in compression ignition. Once a sufficient concentration of free radicals is reached, rapid oxidation occurs (ignition).

quote:

The earliest evaluations of diesel fuels were most likely audible; some fuels caused the engine to operate more smoothly than others.

Hmm..ever notice how when one switches to VO the engine runs much quieter?

quote:

Despite the great efforts over the years to make cetane number determinations accurate, cetane numbers are not as accurate as desired.

Perhaps this is themain reason that despite the supposedly LOW cetane rating of VO it appears to act like a high cetane fuel.

quote:

Serdari et al.16 present cetane numbers for 48 esters. Knothe et al.17 present cetane number data for 29 fatty acid esters. In an earlier paper, Knothe et al.18 list cetane numbers derived from an ignition delay procedure for 21 esters, alcohols, and triglycerides. Freedman et al.19 present data for 20 esters, alcohols, and triglycerides. There is substantial overlap between these sources in terms of compounds studied, and where there is overlap, the agreement is often poor.‡

Tryglycerides = VO.

quote:

Peroxides are compounds with an R – O – O – R linkage. Most peroxides are extremely reactive and many are explosive. Peroxides have long been known to be effective additives for improving the cetane number of diesel fuels.

Peroxides are formed as VO is exposed to heat and O2 and shortly after the injection of VO into the combustion chamber of a diesel engine this exposure is intense. That exposure increases the lower the viscosity since lower viscosity translates directly into better atomization and discpersion of VO droplets in the combustion chamber. The presence of peroxides formed during the preignition phase of combustion may be what effectively lower the autoignition temperature ..and thereby shorten the ignition delay of VO fuel.

Perhpaps THIS is th reason that VO appears to have a low cetane value in testing..but in actual use it appears to have a significantly higher cetane value.

quote:

Originally posted by danalinscott:
Hmm..ever notice how when one switches to VO the engine runs much quieter?

Yes and quieter is not better in this case. This is a very common misperception. Its an indication that because of the longer ignition delay, your timing is retarded. Retarded timing (quieter engine) means you are getting lower power, worse mileage and more emissions. And it burns cooler which leads to more deposits forming. The sound of the diesel knock is how the most accurate tuning for the timing of mechanical IP diesel engines is done, they have special acoustic sensors to measure the knock loudness. All 3 of my VO vehicles are timed so the knock sounds the same on D2 or VO.

Here is a relevant thread from Crossbones who is an expert on the timing subject but has quit posting here:
"Do not be lured into thinking that when using VO as fuel and diesel knock is substantially less that this is better for your engine..."
Update-challange- Glow plugs as sensors (crossbones)

quote:

Originally posted by SunWizard:

quote:

Originally posted by danalinscott:
Hmm..ever notice how when one switches to VO the engine runs much quieter?

Yes and quieter is not better in this case. This is a very common misperception. Its an indication that because of the longer ignition delay, your timing is retarded. Retarded timing (quieter engine) means you are getting lower power, worse mileage and more emissions. And it burns cooler which leads to more deposits forming. The sound of the diesel knock is how the most accurate tuning for the timing of mechanical IP diesel engines is done, they have special acoustic sensors to measure the knock loudness. All 3 of my VO vehicles are timed so the knock sounds the same on D2 or VO.

Here is a relevant thread from Crossbones who is an expert on the timing subject but has quit posting here:
"Do not be lured into thinking that when using VO as fuel and diesel knock is substantially less that this is better for your engine..."
Update-challange- Glow plugs as sensors (crossbones)

AS much as I respect "crossbones" opinion do you have any other more mainstream (less anonymous) information sources that might back up your claims that

quote:

quieter is not better in this case. This is a very common misperception. Its an indication that because of the longer ignition delay, your timing is retarded. Retarded timing (quieter engine) means you are getting lower power, worse mileage and more emissions. And it burns cooler which leads to more deposits forming.

quote:

Retarded timing (quieter engine) means you are getting lower power, worse mileage and more emissions.

That is not the case with my '89 Toyota TDI. With VO or BD blends the engine is quieter, MPG improves slightly, no noticeable loss of power, and the emission tests show very clean running.
However on V100 or B100 you may be right.

quote:

Originally posted by danalinscott:
AS much as I respect "crossbones" opinion do you have any other more mainstream (less anonymous) information sources that might back up your claims

Its well proven that longer ignition delay (=lower cetane) equals retarded timing, along with the effects I list. Apply simple logic, if the fuel is slower to ignite, the burn is later, which is the definition of retarding the timing. You can find this at hundreds of sources, I am not going to do that research for you. Here is a good post from a Cummins engineer detailing the specific changes I list with advanced or retarded timing:
http://dodgeram.org/tech/dsl/FAQ/timing.htm

With an old mechanical mercedes its easy to change your timing by turning a screw on the IP and see the results of retarding the timing yourself: the engine gets quieter.

Here is good research from SAE showing that a diesel gets quiet when the timing is retarded:
http://www.sae.org/technical/papers/2007-01-2278
You can find many more with a simple search.

But the sound being quieter is off topic. Back to the topic, the NREL report I linked completely contradicts your claim that you can fully compensate for the larger ignition delay (=lower cetane) of VO by increasing heat from 170F to 230F. This is because the main thing creating the larger delay is the CID, not the PID. Heat has no effect on the CID. Different types of VO will have some effect since they have different AIT and cetane values, changing the CID.

All of the research you linked is looking only at viscosity. I have shown with links to good research that many other factors matter as well. I have shown detailed research that contradicts your claim, where is the detailed research backing your claim that you can fully compensate for the larger ignition delay (=lower cetane) of VO by increasing heat from 170F to 230F.?

This message has been edited. Last edited by: SunWizard,

quote:

Its well proven that longer ignition delay (=lower cetane) equals retarded timing

quote:

Apply simple logic, if the fuel is slower to ignite, the burn is later, which is the definition of retarding the timing.

That is indisputable....but you don't appear to be reading the info presented.

The lower "cetane rating" attributed to VO does NOT appear to result in a corresponding ignition delay.

quote:

Here is a good post from a Cummins engineer detailing the specific changes I list with advanced or retarded timing:
http://dodgeram.org/tech/dsl/FAQ/timing.htm

With an old mechanical mercedes its easy to change your timing by turning a screw on the IP and see the results of retarding the timing yourself: the engine gets quieter.

Here is good research from SAE showing that a diesel gets quiet when the timing is retarded:
http://www.sae.org/technical/papers/2007-01-2278
You can find many more with a simple search.

Neither of those links lead to reports or info that verify what you claim they do.
Did you mistakenly provide different links than you intended?

quote:

But the sound being quieter is off topic. Back to the topic, the NREL report I linked completely contradicts your claim that you can fully compensate for the larger ignition delay (=lower cetane) of VO by increasing heat from 170F to 230F.

It does nothing of the sort.
In fact it provide evidence that the opposite is true and why.

quote:

Heat has no effect on the CID.

Actually it does..and here is why.

It is undisputed that the lower the viscosity the finer the droplets of atomized VO is created by diesel injectors and the deeper the penetration of the spray pattern is.

It is also undisputed that finer the droplets the greater the exposure of vo molecules to the heat and O2 present in the combustion chamber.

Also undisputed is that molecules of VO exposed to O2 and high heat rapidly undergo reactions that create peroxides.

The concentration of peroxides on the surface of the fine droplets of VO provide a AIT that is significnatly lower than VO has and peroxides combust at an extreme rate. As a result the AIT of VO is not what determines the ignition delay....the AIT of the peroxides coating the exterior of the VO droplets are. This may be why VO does not act as a low cetane fuel would be expected to when it is heated to temperatures where its viscosity is near that of diesel fuel.

quote:

All of the research you linked is looking only at viscosity.

That is incorrect.
Please take the time to read the links before making statements about the information contained in them.

quote:

I have shown detailed research that contradicts your claim

Then please present it.

As I have stated before.

quote:

I gaurrantee that if YOU post links to studies that provide counter evidence to ANY conclusion I have reached I will read them

This is how I noticed that the links you provided in the post I am responding to do not present the information you CLAIM they do.

quote:

where is the detailed research backing your claim that you can fully compensate for the larger ignition delay (=lower cetane) of VO by increasing heat from 170F to 230F.?

I don't believe that I have made that claim.
Can you provide a quote where I did?