The affects of Waste Vegetable oil on TDI's

[aberson]

Now let's think colder. Firstly, although I talked about a coolant loop originally, let's be honest. TDI's don't produce enough heat to keep the cabin warm, so the likely hood of sufficient heat to ungel the fuel line is pretty small, especially close to starting. Hence, my heated pickup idea. What to do about the fuel line? Not so sure on this one. I'm leaning towards electric heat for the whole system, the question is what kind of mods will the electrical system need to support all the heating. Bigger alternator? Second Battery? I don't know.

This is an old thread, but I figured I'd toss a comment in anyway.

I think the whole coolant loop thing is a little shady. First of all, it's not that much heat (as mentioned). And 2nd of all, that's a lot of extra places to have a leak in your coolant system and have a serious problem, not to mention potentially leaking coolant into your SVO.

Electric solves all those problems, but then you have the question of load on the electrical system (as mentioned).

So, what has plenty of heat and don't need to worry about losing any of it? Your exhaust. Googling turns up one place mentionining this, but I don't know if it's really being done in practice. I believe exhaust temps exceed 300 degrees F, plenty of heat there.

Instead of running coolant through the SVO tank heat-exchanger, why not run exhaust gas? Create a little spur off your exhaust pipe, and put some sort of thermostat-controlled-valve on it it to automatically open the valve when the SVO tank is too cold. It would have to be a small spur that didn't have any effect on the pressure of the main exhaust line.

I suppose the same sort of thing could apply to keeping your filter and svo supply lines hot... little shunts of exhaust with thermostat valves. maybe this is more trouble to hook up in practice.

And yes, leaking exhaust into your passenger compartment is a risk (on a hatchback), but I think you'd smell it long before there was a problem.

 

[moondawg]

Exhaust is hot, but doesn't have much thermal mass. It's hard to use it to heat something with alot of mass, like fuel.

 

[narongc73]

People are so ignorant these days. There's a reason they came up with biodiesel, so use it. WVO or SVO i just not worth the risk unless you have extra cash to spend when a failure occurs. Those that weren't successful with using straight VO can complain all they want, no one here will listen because they love to argue. Everyone has their opinions.

 

[N2TOH]

Exhaust is hot, but doesn't have much thermal mass. It's hard to use it to heat something with alot of mass, like fuel.

I remember how bad the heaters were in the air cooled beatles.

 

[McBrew]

I think the whole coolant loop thing is a little shady. First of all, it's not that much heat (as mentioned).

It's more heat than anything else a car has to offer. Think of it this way... let's say our engines are 40% efficient. That means that 40% of the fuel energy goes into mechanical energy (horsepower) and 60% goes into making heat. (these numbers are rough, folks, I'm just making a point).

Now, you are cruising down the highway in your TDI. It takes about 15 horsepower to keep you going. That means the engine is producing 22.5 horsepower worth of heat (actually, the engine is probably less efficient at that load level, but we're just playing with numbers here).

Now, translated into heat energy, that's about 57,000 BTU/hrs. In electrical power, that would be almost 17,000 watts.

Obviously, our electrical systems couldn't even approach that. Things like veggietherms and such are good for supplemental heating, but pumping all that cold oil up to the engine compartment is really going to stress the fuel pump(s). It doesn't seem like a good long-term solution. The best thing to do would be to heat the entire tank of oil with coolant and supplement that with electrical heat at or near the fuel filter.

Of course, like I've said before, I don't think WVO is the best thing for TDIs. It's cool for older, low pressure IDI diesels like Mercedes used to make, or older truck engines... but I wouldn't risk it in a TDI. Go biodiesel!

 

[aberson]

yesterday I was driving a diesel ambulance (as I do weekly) and for the first time, I noticed the coolant temp guage on the dash. It wasn't just marked high/low, but actually had numbers. I didn't see the coolant get over 160 or 170 at all. Seems like it wouldn't be able to adequately heat a tank of SVO.

Not to say that the thing is calibrated at all, or that a freightliner diesel engine is apples-to-apples with a TDI, but just something I noticed.

As for the thermal mass of the exhaust, I agree that it might not be as much as the coolant, but I still figure it's enough to heat 3.2oz of oil per minute. (I come to that flow-rate by assuming that 40 miles/gallon = 40 minutes/gallon at 60mph and then taking the recipricol and converting to oz.) Obviously that doesn't account for pre-heating your ENTIRE svo tank, but maybe you can pre-heat enough near the pick-up point to make it work.

Also, don't forget that not all of those 17kW are in your coolant though, at least some of them must be in the hot exhaust.

 

[robdesigns]

As for the thermal mass of the exhaust, I agree that it might not be as much as the coolant, but I still figure it's enough to heat 3.2oz of oil per minute. (I come to that flow-rate by assuming that 40 miles/gallon = 40 minutes/gallon at 60mph and then taking the recipricol and converting to oz.) Obviously that doesn't account for pre-heating your ENTIRE svo tank, but maybe you can pre-heat enough near the pick-up point to make it work.

The wisdom of using WVO is a separate discussion, but my reasoning for why coolant is a better heating medium:

1. Pre heating the oil at the pick up point is not enough. You need to heat the oil in the whole system to reduce the viscosity and friction as it drawn through the fuel lines. The coolant is the only medium with the heat energy to pull that off quickly and efficiently.
2. The exhaust components are too hot for a low volume of oil. The burned oil will create "varnish" on the metal fuel lines required for contact with an exhaust system.
3. The hot coolant can be directed and controlled much easier than hot exhaust gases. As you add bends to your exhaust, you also add restriction.
4. Don't confuse max temperature with available energy. There is more energy stored in your 180 deg coolant than in your hot exhaust. A kg of water contains 4 times the energy of a kg of air. The density of water is approx 1kg/l, and the density of air is approx 1.2 kg/m3 at sea level. The numbers work both ways, would survive longer in 32deg air or 32 degree water?

heat capacity in J/(kg·K)
Air (dry)1005 J/(kg·K)
Water gas1850 J/(kg·K), liquid 4187 J/(kg·K), solid (0 °C)2060 J/(kg·K)


As the oil is moved through the injection pump, friction in the pump heats the fluid even more. The injectors are right in the combustion chamber, and heat the oil again just as it is injected into a super heated combustion chamber. My fuel system uses a looped return to keep the oil hot. Air is purged back to the oil tank. The stock (bio)diesel tank stays free of WVO.

Regards,

 

[McBrew]

I didn't see the coolant get over 160 or 170 at all. Seems like it wouldn't be able to adequately heat a tank of SVO.

Yes, but remember that your thermostat is regulating coolant flow to the radiator, which is shedding excess heat. Adding WVO to the 'loop' is just like adding more coolant. It will take longer for the coolant to reach full operating temp, but as long as there isn't too much of it (especially if it is not insulated well), it will bring it all up to the same temp, then use the radiator to shed excess heat... just like normal. Most serious WVO users have temerature gauges for the oil to know when it is hot enough to switch over.

Yes, it is true that "wasted" energy is lost through the exhaust as well as other places... but the majority of that energy goes into the coolant.

 

[aberson]

1. Pre heating the oil at the pick up point is not enough. You need to heat the oil in the whole system to reduce the viscosity and friction as it drawn through the fuel lines. The coolant is the only medium with the heat energy to pull that off quickly and efficiently

Agreed. but as long as you're heating fast enough, you don't need the entire WVO tank to be hot before you switch over. True though that if you only heat the tank, your fuel lines will still be frozen when you switch over.

2. The exhaust components are too hot for a low volume of oil. The burned oil will create "varnish" on the metal fuel lines required for contact with an exhaust system.

Agreed. Would need a way to turn the exhaust flow on/off through the WVO heating loop (see my #3 reply), (e.g. thermocouple, microcontroller, and valve)

3. The hot coolant can be directed and controlled much easier than hot exhaust gases. As you add bends to your exhaust, you also add restriction.

Agreed. I guess I'm thinking of T'ing off from the main exhaust pipe with a small diameter pipe, and then having a valve to open/close this secondary pipe. Because it's a small diameter, it would have less heat to begin with, and I don't think it would significantly impact real exhaust operations.

4. Don't confuse max temperature with available energy. There is more energy stored in your 180 deg coolant than in your hot exhaust.

Agreed. But would you agree that if I poured 6oz of cold oil on my 300-600 degree tailpipe, it would probably be above 200 degrees in under a minute? Without doing the thermodynamics, my guess is that it would.

Here's one reason for wanting to go above 180 degrees:
You're probably going to call me a whacko for this idea, but you obviously know a lot about this so tell me what you think. I'm not sure it would actually work because I'm not sure how the water is actually suspended in the oil. After filling up with a fresh load of filtered WVO (directly into my tank), heat the WVO tank to say 230 F for 5 minutes (temps and times could change, of course). Any water in the fuel should vaporize and bubble out as steam, and escape to the outside through some sort of vent. It should be safely below the smokepoint of the oil.

The idea is to not worry about settling the WVO for weeks before using it, but just have a good filter while pumping, and then use the exhaust heat to de-water. You could have a function as part of a microcontroller controlled WVO system; you hit the dewater button, it runs the cycle as you drive, and as soon as the cycle has run for 5 minutes total (even if not contiguously), it lets the oil cool back to driving temp before allowing you to put the WVO into your engine.


adam

 

[robdesigns]

Agreed. but as long as you're heating fast enough, you don't need the entire WVO tank to be hot before you switch over. True though that if you only heat the tank, your fuel lines will still be frozen when you switch over.

Someoine made a wonderfully analogy of sucking a milkshake vs. water through a straw. Cold vs warm oil over a 10ft long straw would not be much different. All the heat in the tank will be absorbed by the hoses and radiated away by the time it gets to the front. 1-2 feet of unheated hose stays warm in my engine compartment.

Agreed. Would need a way to turn the exhaust flow on/off through the WVO heating loop (see my #3 reply), (e.g. thermocouple, microcontroller, and valve)





Agreed. I guess I'm thinking of T'ing off from the main exhaust pipe with a small diameter pipe, and then having a valve to open/close this secondary pipe. Because it's a small diameter, it would have less heat to begin with, and I don't think it would significantly impact real exhaust operations.

You are going to weld "T"s and valves into an exhaust system????? Hot water in a hose just makes so much more sense.

Agreed. But would you agree that if I poured 6oz of cold oil on my 300-600 degree tailpipe, it would probably be above 200 degrees in under a minute? Without doing the thermodynamics, my guess is that it would.

Here's one reason for wanting to go above 180 degrees:
You're probably going to call me a whacko for this idea, but you obviously know a lot about this so tell me what you think. I'm not sure it would actually work because I'm not sure how the water is actually suspended in the oil. After filling up with a fresh load of filtered WVO (directly into my tank), heat the WVO tank to say 230 F for 5 minutes (temps and times could change, of course). Any water in the fuel should vaporize and bubble out as steam, and escape to the outside through some sort of vent. It should be safely below the smokepoint of the oil.

I do not think you are a wacko, but your tail pipe is not 300 to 600deg. Set a tuna can full of WVO on your exhaust (that sounds wacko and a fire hazard) and see how long it takes to heat up to 230 degrees. Anything over 15 min is too long. Theoretically at 50 miles per hour you are consuming 1 gallon an hour (50 miles per gallon).

The idea is to not worry about settling the WVO for weeks before using it, but just have a good filter while pumping, and then use the exhaust heat to de-water. You could have a function as part of a microcontroller controlled WVO system; you hit the dewater button, it runs the cycle as you drive, and as soon as the cycle has run for 5 minutes total (even if not contiguously), it lets the oil cool back to driving temp before allowing you to put the WVO into your engine.

Just settle it, and collect from the top maple syrup looking stuff. Leave the chocolate looking stuff for the home brewers.

Before I get flamed my 15 gallon "crab"appleseed processor should be ready by spring

 

[aberson]

You are going to weld "T"s and valves into an exhaust system????? Hot water in a hose just makes so much more sense.

Well certainly cutting into the exhaust doesn't appeal to me, but if it had major advantages over the hot-water method then I'd consider it.

I do not think you are a wacko, but your tail pipe is not 300 to 600deg. Set a tuna can full of WVO on your exhaust (that sounds wacko and a fire hazard) and see how long it takes to heat up to 230 degrees. Anything over 15 min is too long.

the 300 F was a rough estimate based on googling around and seeing EGT ranges of 400-1000 F. Even if that is the temp right at the turbo, I figure it's gotta still be pretty hot coming out of the tailpipe. Worth measuring though.

You have a bit of a point about time though. Let's say it took 20 minutes to get an entire SVO tank up to "230" degrees, and then I need to leave it there for another "10" minutes to boil off all the unsettled water. If I only have to do that once after each fillup, then it's no big deal. All I'd have to do would be to make sure that I have a 30-minute long drive before I start using my fresh tank. So I'd just have to wait until the next time I drive to work. A few minutes longer is no problem either, could just take the "long way home" one day. Basically it would cost me half a gallon of dino-diesel to dewater 13 gallons of WVO. If it took much longer than that, then it might not be practical simply due to time.

Just settle it, and collect from the top maple syrup looking stuff. Leave the chocolate looking stuff for the home brewers.

Part of my problem is that I live in a 2nd floor apartment. To be able to carry it upstairs to settle, I'd be limited to 5 gallon jugs, and even that would probably get pretty too heavy. The only other solution would be to have a settling container located at my WVO source that I can pump straight ouf of.

 

[DuluthRooster]

20,000 trouble free miles on my Plantdrive (Neoteric) kit so far. Jetta runs great. Based on the above posts, go figure.

2002 Bora Wagon 53,000 miles and just out of warranty

 

[bungy42]

I have a temp gauge in my WVO tank in the trunk. I have an hour drive to work, and the WVO only gets to roughly 140F. On the bright side, it takes just as long to cool off, so it's still in the 70's when I get out of work. I haven't had the time yet to install a temp sensor near the engine, so I don't know how much more heating I'm getting from the heated filter and heated fuel lines.

 

[Jumping Jack]

I converted my Jetta 2000 to 143 000 km with a setup 2 tanks, the same one as that of Greasecar.com.
Heated spin-on filter, heated allu tank, backflush feature, vegtherm, temps guage.

To did 265 000 km I have changed of injection pump, why you will require of me?

3 answers possible:
1) WVO utilisation.
2) Fair wear and tear of a pump to 265 000 km because of the bad diesel which we have in Canada.
3) Pompe with a manufacturing defect (I have had all the existing problem with my TDI for 2 years, then I am pret with saying that I have a lemon!).

It is certain which utilsation WVO must- to be made with attention. Good quality of oil, filtered well, dewatering.

 

[Jumping Jack]

I have a temp gauge in my WVO tank in the trunk. I have an hour drive to work, and the WVO only gets to roughly 140F. On the bright side, it takes just as long to cool off, so it's still in the 70's when I get out of work. I haven't had the time yet to install a temp sensor near the engine, so I don't know how much more heating I'm getting from the heated filter and heated fuel lines.

It is more significant to know the temperature at the entry of the pump than of knowing how much it makes in the tank!

 

[BioDiesel]

Couldn't resist this one:

WVO or SVO i just not worth the risk unless you have extra cash to spend when a failure occurs.

Only a fool would continue to spend $3/gallon on petro or biodiesel, or spend the energy and time to make biodiesel. The savings acrue 3x faster than repair costs, even if my fip croaked tommorow.

I spend $200 / year on fuel to go 23,00 miles. Period. And 1 hr / week collecting and filtering WVO. Period. Been runnning fine for 32k miles. Can anyone beat that?

 

[ChuckDubDub]

I have a temp gauge in my WVO tank in the trunk. I have an hour drive to work, and the WVO only gets to roughly 140F. On the bright side, it takes just as long to cool off, so it's still in the 70's when I get out of work. I haven't had the time yet to install a temp sensor near the engine, so I don't know how much more heating I'm getting from the heated filter and heated fuel lines.

Have you tried a VegTherm?

Getting a GC kit next month, and I'm in Metrowest Mass. Seemed to make more sense to me than BioD, because I didn't want to mess with the nasty chemicals in the basement (no garage), also in theory the WVO system can be used year-round.

-Chuck

 

[bungy42]

Have you tried a VegTherm?

Getting a GC kit next month, and I'm in Metrowest Mass. Seemed to make more sense to me than BioD, because I didn't want to mess with the nasty chemicals in the basement (no garage), also in theory the WVO system can be used year-round.

-Chuck

I've thought about installing the VegTherm, but since I don't have a temp sensor at the injection pump, I don't yet know if I need one. If I do need one, I'll wind up making my own. The VegTherm is overpriced in my opinion. If you need help/tips on your GC kit install, let me know.

 

[aberson]

since I don't have a temp sensor at the injection pump

I was considering using cheap thermistors to measure temp on the outside of the IP, in the fuel tank, and in a few other places. The absolute cheapest thermistor Digikey.com has in small quantity is 44 cents, with a 5% precision - part# B57891M474J - should be good enough. They have plenty of cheap ones though, I just haven't looked too hard. You can go to 1% accuracy for $1.28 - B57861S104F40

You'd have to build some circuitry to measure it from a pretty gauge, but if you just want a temporary measurement you can use a multimeter and a some math to read it (http://www.cpemma.co.uk/thermistor.html - write a quick excel table using that formula and then find the resistance in the table closest to what you're reading on the meter). If I ever do this, I was going to use a small microcontroller to read all the sensors, automate switch/purge, etc.

 

[Caddyboy]

(I can get away with a single-tank conversion since I live in northern California.)

Bishop, Lee Vining, Mammoth & a lot of heavy snow/cold areas in NoCal. Will your vehicle do OK in Mammoth where it was 12 below zero the other night?

 

[quartersaw]

I have a temp gauge in my WVO tank in the trunk. I have an hour drive to work, and the WVO only gets to roughly 140F. On the bright side, it takes just as long to cool off, so it's still in the 70's when I get out of work. I haven't had the time yet to install a temp sensor near the engine, so I don't know how much more heating I'm getting from the heated filter and heated fuel lines.

Go to Home Depot and buy a hot water tank insulation blanket and wrap it around your WVO tank.

 

[BioDiesel]

Will your vehicle do OK in Mammoth where it was 12 below zero the other night?

Mind if I answer?
Lows don't matter as much as avg 4-hour temperature.

For a s-t Elsbett, you'd need to ensure:
a.) the fuel was liquid at -12*F. Not sure how much diesel or kerosene would be needed, but it would be the majority of the fuel, maybe 80%.

b.) the engine was warmed to 70*F either electrically or with an Ebersbacher ( or equivalent ) diesel powered coolant heater. If you can't warm the engine to 70*F, at least ensure the viscosity of your fuel is equal to B100 at 30*F.

 

[Vegi_VW]

(I can get away with a single-tank conversion since I live in northern California.)

Bishop, Lee Vining, Mammoth & a lot of heavy snow/cold areas in NoCal. Will your vehicle do OK in Mammoth where it was 12 below zero the other night?

I believe Caddyboy's comment is in response to my post. Although I'll bet it wouldn't be hard to find native Californians to dispute his characterization of Mammoth as NorCal, he's correct in that I chose my words poorly. What I should have said was "I can get away with a single-tank conversion since I live in the SF Bay Area, where the temperatures almost never fall below freezing." Although (as BioDiesel's experience shows) it is possible for an Elsbett single-tank system to thrive in cold temps, if I lived in Mammoth I would have gone with a two-tank system.

And props to Caddyboy for reading all the way through this thread. That post was from eight months, nine pages, and about 9000 miles ago.

 

[moondawg]

I've thought about installing the VegTherm, but since I don't have a temp sensor at the injection pump, I don't yet know if I need one. If I do need one, I'll wind up making my own. The VegTherm is overpriced in my opinion. If you need help/tips on your GC kit install, let me know.

You DO have a temp sensor on the Injection pump. You just need VAG-COM to read it. Fuel temperature is available.

moondawg

 

[bungy42]

You DO have a temp sensor on the Injection pump. You just need VAG-COM to read it. Fuel temperature is available.

moondawg

Yes, I know. But installing a second $5 sensor is a whole lot cheaper than buying a vag-com.

 

[Smokerr]

On a side note, I wondered why my car used over half a litre of oil since I got it. They kept my car to fix the leaking oil problem. I never saw the leaked oil because it was all being caught by that pan under the engine. I think its the valve cover gasket. All that shielding does have disadvantages.

Don

If mine only used ½ quart in 5k I would think nothing of it.

Me, I pulled all that plastic stuff off the top of the engine so I can see what’s going on.
Only downside is a bit more noise, but what the heck, both my wife and I drove big diesel trucks in the past, and at its worst its better than those things (she drove diesel tractor and gasoline trucks with electric two speeds, and I drove gas trucks with two speed electric rear ends to 12 cylinder rock trucks that used the bed as an exhaust and muffler, so when it was up, you had a 12 cylinder two cycle 700hp screaming maniac of an engine in your ear!)

 

[Route 66]

The State of Minnesota mandated the use of Biodiesel at the end of September 2005. The blend was put at 2%, and truckers specifically had clogged fuel filters starting in November which caused the use of biodiesel to be halted for 30 days until the glycerin levels could be dealt with.

 

[KYFried]

The clogged filters was likely due to gunk removed by the biodiesel from the tank and lines. This is typical on the first 1 or 2 tanks of biodiesel and the gunk is usually bacterial slime growing in the diesel fuel system. Biodiesel is a much better solvent than diesel.

 

[SimBG]

Since you seem to know much more than me about WVO and Biodiesel, I though you could help me. I'm new to cars (tried to avoid using one as much as possible but right now I got one). At least it's a 2001 TDI Jetta I could have cheap from my mother ! Yay.

But enviro friendly as I am, I gotta to convert is to Veggie, BD or WVO... Although not recommended, from what I see WVO seem to have enhanced a lot in the last few years and if filtered and dried correctly, would be OK... I saw this system from a dealer near my house and seemed not bad.. Though the 1500$CAD (1300$US) cost of conversion is important, I'll pay it in less than five years, but I couldn't afford new injectors over that..
http://vegetalcar.com/Temoignage.asp?Temoignage=4
http://vegetalcar.com/Detail.asp?Texte=Mecanique
The system seemed to my as a high quality one. It got the 6 valve port, stays close to the motor for easier oil heating, has something like vegtherm...

Biodiesel, you seem happy to quit the use of Biodiesel and to have some contact in Montreal who made the switch, if I could have his contact and if the guy doesn't mind that much to help me a bit in my choices, I'd be really happy.

Thanks a lot for the help... I still have two months to go before the big switch. Right now I'm not home and living -25°C so I'll wait a little ;-)

 

[NFSTDI]

OK, so I am going resurrect a dinosaur. I have an E300TD with a single tank Elsbett kit. I bought it that way. After significant research, and some less than satisfactory experience wasting money on repairs, after running BioD in my prized TDI, I decided to do the smart thing. I bought a cheap car that was already converted.

I recently had my Benz looked at by someone who knows about these things, because, I don't...or I didn't. I gave it to him to make sure it was up to snuff and to help me understand my Elsbett kit. The guy I bought the car from was not the actual owner, so he could tell me all of nothing. My trusted WVO BioD mechanic put fifteen gallons of WVO in my trusty MBZ.

My car ran just fine so I picked up about eighty gallons of oil from my friends restaurant. Actually, I already had five gallons he gave me a while back so I checked that for water content, filtered it with a two stage system I built, one rough filter, one five micron sock, and it looked real good. I poured that in my tank, along with another five gallons I filtered that has not settled quite as long. Given how clean my oil seems to be, I am not too worried about it. Worst case scenario, I will simply junk the car, if it comes to that. I really did not pay much for it.

Anyway, now that I have a good supply of oil, a car that seems to like it, and a good strategy for filtering oil, I am tempted to experiment with my Jetta. I was dead set against that until the other day I picked up some oil from a guy who has been running his TDI on WVO for like ten years!

My research indicates that nearly all of the problems associated with running WVO stem from careless users who fail to secure a clean oil supply and simply do not understand how to make sure there is no animal fat, water, nor particulate matter present, before pouring it in their cars.

Can anyone dispute this, or give me any advice. I am not looking for the opinions of mechanics who have seen problems. I am looking for first hand accounts from those who have been doing this for some time.

Why did I resurrect this thread, two reasons.

1) It is at the top of Google when I search for running WVO in a TDI.

2) I would love to see some follow ups from those who posted here previously.

TIA