bio diesel and WVO

[Oonrahnjay]

(snip) If a Detroit is cycling a gallon of fuel per minute back to the tank, simply running the return line alongside a warm coolant hose should warm it enough to heat the tank. Then run the feed line close to the engine so it picks up more heat before coming through the injectors. 

    Art, the heating system for a veg-oil system has to heat the oil to working temp before it ever goes into the injection system.  And it's got to have enough heating capacity to keep the oil hot under all conditions (like when you're going down hill and the fuel flow is low) and also to make up for heating losses when the fuel is being transferred from the heater to the engine. 

    It will take a while to get *any* heat out of the from the return line into the feed line as you described.  And without a carefully designed and efficient heat exchanger, you wouldn't get nearly enough heat out of the returned fuel to bring the feed oil up to working temperature.  And, especially, you'd never be able to get enough heat to make any difference in a "cold start on veg-oil" scenario.

    I've looked at veg-oil systems a lot (I've run a diesel car for many years -- in fact, we've been an all-diesel household for almost 10 years) and I haven't found anyone who's designed a usable heating system that doesn't use up-to-temp radiator coolant to heat the coolant.  (Some people add electric heaters to "assist" just before the oil goes into the engine but the main heating energy comes from engine coolant.)

[artvonne]

  I understand it needs some heat, but what is the low limit starting temp? Knowing the parameters would go a long ways in understanding where to start.

  Diesels arent gas engines, they dont tolerate starting and stopping as gas engines do, and large diesels like it even less. By its nature a Bus was designed to run all day and night continuously, and they like running that way. In starting, even in warm summer daytime temperatures Ive never seen a diesel that liked starting cold. They still clack and knock for a bit until the combustion chambers warm. Just knowing WVO is thick and viscous, and has a higher flash point (323-540F vs 143F), tells us its going to be much harder to crank up when cold. But once running and heated, and provided the setup gets enough heat into the fuel to burn properly, the cold start shouldnt cause to much trouble provided it warms fast and you dont shut it down until its ran long enough to run hot and clean. Therefore I would imagine short run times on oil to be much more damaging than on diesel.

  My greatest concern would be causing engine damage. Ive read for a while of WVO causing coke and carbon deposits, sometimes rapidly. While I havnt read it, its likely simular to an engine thats burning engine oil, where they start building carbon on the exhaust valves. In a diesel, if the fuel isnt burning its going to do the same thing. Therefore its likely much more important to use the right injector and injection timing, probably more advanced.

 

[bevans6]

Why do you think diesels don't like to start and stop?  I have never heard of such a thing before.  I agree that if they are under load they can run continuously, but the advice is don't idle them, turn them off and start them again when you need them.  I'd appreciate understanding this better.

Brian

[artvonne]

Why do you think diesels don't like to start and stop? 
Brian

  No engine likes short trips. If an engine doesnt run long enough, it wont burn off moisture. And everytime you start a cold engine they create a moisture, to greater or lesser or degrees depending on humidity and ambient tempertures. Ive seen many engines that had so much moisture in the oil they were milky. In most cases its was a car used to drive short distance to work and back, short trips to grocery, etc., and back, being shut off and allowed to cool, then fired up again. Most times in a MN winter, the engine dont even start putting out heat and people shut em off. That really shortens engine life.

  A diesel is even worse. They are slower to warm up and thus can put more water into the oil if they dont get moving fast enough. And if they dont run long enough to burn it off, it continues to accumulate with each cycle same as a gas engine. And oil analysis shows this, diesel engines that run continuously such as OTR trucks, can put many more miles on thier oil than engines used in short cycles such as fire depts. Running hard and long is far better than easy and short. And I should mention the same applies to diesel generators but for an additional reason. They need to run at more than half rated load if you expect them to have any reasonable life expectancy. Running under light load will carbon the cylinder bores until they are so smooth they lose compression and die.

[buswarrior]

Wow, that's a whole lot of unrelated issues rolled into one...

Condensation from short trips? Anthropomorphized engines?

The WVO folks are trying to tell us that we need to have diesel in the lines if we are going to turn it off, in order that we can get it to start, and warmed up in order to support WVO ignition.

The WVO can pretty much be considered to be at risk of congealing in the lines and injectors as it cools, preventing flow, never mind trying to get it to ignite by compression ignition with no heat in the engine to help it reach ignition temperatures. You don't get any heat until you can get a fire, and you can't get it to fire without heat. Where's the heat going to come from?

And it isn't like starting a diesel in Minnesota, or Alaska, both of which are easy, and done often, in 2011.

Using your numbers - "(323-540F vs 143F)"  the smallest spread in your provided ignition temperatures between diesel and WVO is 180 degrees, or higher. So, in the cylinder, you have to get WVO at least 180 degrees hotter than diesel to get ignition.

To keep the challenge of 180 degrees hotter in perspective, using a comfortable starting temperature of 50 degrees, where even our most tired 2 strokes will start, and then go down to -40, that is only 90 degrees difference.

A running engine at 180 degrees is only 130 degrees hotter than the 50 degrees we started at.

And more O/T myth busting, winterized diesel fuel from the pump will flow, fire and run just fine down at arctic temps, using a traditional block and oil pan heater, never mind the ancient myths from when the highways in Alaska were gravel, the fibs were more numerous than the mosquitoes, or the engine owner doesn't maintain or prepare for the winter.

You have to get the WVO in the cylinder up to ignition temps, and that delta temp is really hard to  achieve without the help of an already warmed up engine.

So, in summary, the WVO folks are saying WVO is not going to be very cooperative on a 50 degree morning, we need to start on diesel.

Kindly remember that we have a responsibility to the newbies who follow, they are mislead when we emphatically repeat information that we have not verified from reliable sources.

happy coaching!
buswarrior

[happycamperbrat]

BW good post! Thanks!

But I would hope there wouldnt be a newbie around who would not do their homework before playing with wvo! The engines have to be started and stopped on diesel....... you cannot leave vo in the lines or the engine, or you wont have one to worry about for long. The first 5-10 miles and last 5-10 miles should be run on dino.

[buswarrior]

You're welcome.

The thread was supposed to be about WVO, and got other stuff tagged on that is not helpful to a wanna-be busnut absorbing everything they read about heavy diesel engines.

If this board is to be of any value to busnuts now, and busnuts in the future, the information we share needs to be correct.

Otherwise, we're just another lowest common denominator noisy internet place.

happy coaching!
buswarrior

[Oonrahnjay]

(snip)  You have to get the WVO in the cylinder up to ignition temps, and that delta temp is really hard to  achieve without the help of an already warmed up engine.

So, in summary, the WVO folks are saying WVO is not going to be very cooperative on a 50 degree morning, we need to start on diesel. (snip)

    Yes, those were the points that I was trying to get to (well and succinctly put - thank you).  And there is also a second point, relating to the handling of WVO.   That is that WVO contains heavy fats often called fatty esters -- chiefly glycerin and similar chemicals -- that will precipitate into solids or very thick "sludgy" liquids unless heated to a temperature in the 150-170 degree range.  All WVO systems have a method to provide this heat.  A secondary need is that WVO is much thicker than petro diesel at ordinary temperatures, it must be warmed to thin it out to be pumped, filtered and otherwise handled in the fuel system.

    Failure to heat the fuel properly can have serious effects.  If you're lucky, cool fuel will clog your filters, lines, injector pump and injectors with a soapy slime that you'll have to clean out on the side of the road.  If you're not lucky, this soapy slime will burn into a carbony coke deposit in your injector pump and injectors, resulting in a necessity to have your injector pump and injectors rebuilt or fuel spray patterns inside your engine that will burn your pistons and cylinder walls like an acetylene torch.

     So -- completely irrespective of whether you can get the engine to start on WVO or not, you must provide a way to heat WVO before it's introduced into the engine's fuel injection system.  And that system must be robust -- it must provide enough heat to assure that the WVO is still hot enough when it gets to the engine and it must be hot enough to keep that heat as it moves through the system (i.e. it must be warm enough so that if cools down a little, it's still warm enough to be pumped and burn properly).  And a running engine isn't always the same -- but this I mean that fuel in the lines may cool down a lot more if you're slowly descending a long hill at 20 degrees (F) than if you're running full speed across the desert when it's 97 degrees.  WVO fuel heaters must provide enough heat into the fuel to cover all conditions.

    And the heat from returning fuel just does not have nearly the energy to do this.  In fact, it will most notably fail in the "going slowly down the long hill at 20 degree" scenario.  That's the point I was trying to make before we got sidetracked into the "how much heat is in WVO in a cold cylinder at startup" discussion.

    So, I'd add to BW's statement to read "we need to start on diesel and we need to have WVO heated to a safe working temperature before it enters the engine's fuel handling system".

[5B Steve]

Wow, that's a whole lot of unrelated issues rolled into one...

Condensation from short trips? Anthropomorphized engines?

The WVO folks are trying to tell us that we need to have diesel in the lines if we are going to turn it off, in order that we can get it to start, and warmed up in order to support WVO ignition.

The WVO can pretty much be considered to be at risk of congealing in the lines and injectors as it cools, preventing flow, never mind trying to get it to ignite by compression ignition with no heat in the engine to help it reach ignition temperatures. You don't get any heat until you can get a fire, and you can't get it to fire without heat. Where's the heat going to come from?

And it isn't like starting a diesel in Minnesota, or Alaska, both of which are easy, and done often, in 2011.

Using your numbers - "(323-540F vs 143F)"  the smallest spread in your provided ignition temperatures between diesel and WVO is 180 degrees, or higher. So, in the cylinder, you have to get WVO at least 180 degrees hotter than diesel to get ignition.

To keep the challenge of 180 degrees hotter in perspective, using a comfortable starting temperature of 50 degrees, where even our most tired 2 strokes will start, and then go down to -40, that is only 90 degrees difference.

A running engine at 180 degrees is only 130 degrees hotter than the 50 degrees we started at.

And more O/T myth busting, winterized diesel fuel from the pump will flow, fire and run just fine down at arctic temps, using a traditional block and oil pan heater, never mind the ancient myths from when the highways in Alaska were gravel, the fibs were more numerous than the mosquitoes, or the engine owner doesn't maintain or prepare for the winter.

You have to get the WVO in the cylinder up to ignition temps, and that delta temp is really hard to  achieve without the help of an already warmed up engine.

So, in summary, the WVO folks are saying WVO is not going to be very cooperative on a 50 degree morning, we need to start on diesel.

Kindly remember that we have a responsibility to the newbies who follow, they are mislead when we emphatically repeat information that we have not verified from reliable sources.

happy coaching!
buswarrior

If you add a fuel enhancer(oxidizer to your mixture it will eliminate the problem on combustion.

Steve 5B....

[wal1809]

Sorry bus people I was away from the conversation for a day or two as I was in Austin attending an in service training school.

ALright what I am beginning to read on here is a little cornfusion.  Maybe I can offer a little help in the understanding of WVO systems and why they are important to construct, the right way.

Cold WVO will start an engine.  We don't heat it so it will start the engine.  Lets be very clear with this, don't run your engine on cold WVO.  In my opininion cold oil will destroy an engine.  There are no shortcuts there is no substitute.  Heat the oil to 180 degrees prior to engine entry or your going to create a problem.  This is not a problem that manifests overnight or right when you turn the key.  It takes time but it will destroy your engine.

Here is why.  In the grease we have a thick nasty substance we can call glycerin.  It has to be dealt with prior to engine entry.  YOu either use chemicals to remove the glycerin (bio Diesel) or you heat it to 180 degrees F prior to engine entry.

With bio diesel it is easy to understand the glycerin won't cause trouble because we have already removed it with methoxide (Lye and methanol).  When WVO is heated to 180 degrees and it allows a couple things to happen.  It causes a better spray pattern in the cylinder chamber causing a more even and thorough burn of all material sprayed through the injector.  WIth that being said the glycerin is dealt with right then and there, by being turned to a vapor and out the tailpipe.  If you don't heat it then glycerin will slowly leave a brown tar looking residue which will eventually become like black charcoal on the tips of the injectors and in the rings, called coking.  When that happens your engine is done for.

I have known blenders who run a blend of diesel gasoline and WVO in the main tank and that is all they do.  I will shy away from blending as I don't believe in it.  I have seen trouble with blending. 

So far as my bus I run a heated system which used engine water to heat the WVO.  I don't think throwing diesel onto the WVO to give it a little more help would be such a bad thing or bad idea at all.  I hope this helps.  W

[Charley Davidson]

Running WVO has pretty much been (close to) perfected, so why reinvent the wheel? Why take chances with short cuts? Why question success?

Follow what the masses of successful WVO burners tell you and you'll more than likely have great success also, play with short cuts and it's gonna bite you in the you know what $$$$$$

[artvonne]

  I thought this thread was to learn about WVO. I did not think I needed to be schooled about starting diesels in Minnesota, in winter, which is easy, in 2011. At least not seeing as how I actually lived in Minnesota for 50 years, over 10 years of that in Duluth where I learned to drive, and have been starting diesels up there and everywhere since that time, since about 1975, long before 2011, year round. And you wanna talk about thread drift?

  To everyone else, thank you. I knew there was a problem with coking, but never have been able to find what the mechanism was. I also never knew the oil was decomposing within the system after shut down, thickening, turning to goo, paste, ive never read that in this kind of detail anywhere. In fact, ive actually learned more about the actual physical problems with WVO in the last few posts than I was ever able to find anywhere else.

  But the truthis that without knowledge, the only way we can advance is through imagination, assumptions, and trial and error. Math and science are useless without a question to ask. Only through the posing of questions, and making assumptions, can we use math to guide us, and ultimately, if were smart, we'll use trial and error to test the math. History is replete with attempts to trust math without testing.

  So without the above recognised knowledge, I assumed VO would act like any oil, heat it it thins, cool it it thickens. I had asked several times what the low limit starting temperature was, as well as mentioning coking, but with a lack of answers I was stuck making assumptions. No, I was not trying to reinvent the wheel, I was trying to understand why the systems being created had to be so complex, to see if it truly had to be so complex, or to see if there was a way to simplfy it.

  While I was chastised for ever thinking such thoughts, I would point out that in Germany, today, in 2011, they have actually been building SVO cars, single tank VO cars, that start and run on straight VO, without any diesel purging and extra tanks and valves and pumps and whathaveyou. So while some may think im an idiot for supposing such a thing was ever possible, im really not the only idiot who thinks so. But I have no idea how their are getting around the problems being discussed in this thread.

[wal1809]

Hello Art.  I am glad we are talking and I am glad your thinking out of the box.  Thinking out of the box is what got us all interested in Alternative fuels in the first place. If Rudolph Diesel had not thought outside the nasty little box we would not be talking about wvo systems today.  Graham Lehming thought outside the box when he came up with using a vacuum venturi to drive off the methanol in bio diesel, thus allowing the soap to drop out of the bio diesel without washing it.  Now that my friend was nothing short of genius.  I am sure people scoffed at his idea in the beginning.

So please never think I am laughing, scoffing or dismissing your thoughts or questions.  If you are going to set up your system I will be more than glad to lend what I have learned so far.

Now as for the German vo systems.  My jettas glow plugs are lightning fast.  They only turn on for maybe a half a second.  I am thinking they figured out how to heat the vo instantly at the injectors.

[wal1809]

This photo is of the WVO system I built for my bus.  It might seem complicated but in reality is is very very simple.  I took an old piece of angle iron bed frame.  I welded a cap at either end so I could bolt it in place.  There was all that unused space between the engine and the door so I decided to use it.

Let to right along the angle iron.  Both of the 3 way valves are on the far left.  A vacuum gauge, two 12V relays to operate the valves, a filter housing from Northern tool, tucked behind it on the other side of the frame is a flat plate heat exchanger.  Today I will take pics of the rest and throw them in here.  I will take photos of the surge tank and the other heat exchanger and the big tank and its plumbing.  What you see here is the meat of it all though.

[wal1809]

That picture is a little bit on the crap quality side.  I will take some better photos when I can.

The original post was a poll.  Take a look at the numbers on who is WVOing and who wants to be a WVOer.  I would say pretty impressive in the few numbers of votes.