I know this has been hashed over before. Coolant works great, but what about using a temp switch in the tank, a fuel diverter valve, and a pump to run a WVO through a few coils that are wrapped around the exhaust pipe near the rear of the truck? Anybody use a IR thermometer to check the temp back by the muffler? What about the temp of the muffler shell itself? I know there is a variance based on load, ambient temp, etc., but my thinking is that WVO boils much higher than water, and if the WVO in the coils gets up to 250F it shouldn't boil, and will help dry the WVO. I'm also not talking about wrapping the whole pipe. Just a few turns with a high flow pump. By using a high flow pump, you'd put a little heat in a lot of WVO.
Of course the pump could double as a lift pump assist, and the diverter valve would be used to shut flow off to the inlet of the coils, but the outlet would remain open. That way any pressure buildup would vent to the tank. I was also considering putting a centrifugal filter in this line (check my other post in this forum). You could also wire the temp switch to be a safety to your main diverter valve, so you didn't run WVO through the engine until it was warm enough. You could arm a switch to change over, but the switch in the tank would be the actual trigger. It would be a simple enough electrical circuit, and could be made for a couple of bucks.
I think you may be onto something. In waste processing we use heat to separate oils and waters... but it would need some sort of vent for the water vapors to escape. Any ideas for a vent port? What about a mushroom type breather cap?
I like your idea of a pump to circulate the heated veggie around the exhaust, serving double duty as a boost pump to help the truck's lift pump. Would you make some sort of temperature sensor to open and close the loop around the exhaust? Watching it and switching manually would work for the short term but it seems some sort of process controls would be very helpful.
Keep us posted on your progress.
Todd T
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2002 F-250 Lariat, PSD, CC, short bed, 3.73, auto tranny, Line-X bed liner, AFE Filter, HX crossover, intake heater delete, Evans NGC+, Dieselsite 203 thermostat, coolant filter, Amsoil by-pass filter, Schaeffer's synthetic blend tranny fluid, Bob Riley's tranny filter, Velvet Ride shackles, Rancho 9000 shocks with in-cab adjustment, 60 gallon aux tank for burning heated WVO, burning veggie since fall of '04.
One thing I worry about using the exhaust heating system as described above is what happens when you close the valve to the exhaust loop when your oil is hot enough? As in, what happens to the oil that is currently in the loop and just keeps getting hotter and hotter until... what? smoke? fire? If you manage to drain the exhaust loop, how hot will the loop itself get? What about scorching of fuel inside the empty loop?
Maybe you have some kind of heat exchanger that uses coolant to extract the heat from the exhaust, then depending on the oil temperature, dumps the heat into the oil or to an external radiator. The coolant keeps circulating the whole time, never gets too hot.
Well, I don't have an infrared pyrometer, but I would guess the exhaust at the rear of the truck and the muffler housing shouldn't be over 250F-300F. The gasses in the pipe next to the turbo are hot, but that's way up there... inside the pipe. So, if my guess is correct the hottest the oil in the tube would get would be around 250F or so. It should be stable at that temp. Don't fast food fryers run at temps higher? I don't think you could get a fire in the line, but I could be wrong. I am just throwing out an idea, hoping somebody knows more exact temp answers. Anybody got an IR pyrometer? Check the pipe temp after a hard run back by the muffler, and let me know how hot it gets.
Yes, the temp switch in the tank would open/close the valve to the inlet of the heat exchanger (tubing wrap). Like I said, I'm not talking about wrapping the exhaust 300 times all the way to the engine. I'm talking about 5-7 wraps back by the muffler, where it's had time to cool. Only the inlet would be shut, so any pressure increase would still be open to the tank. The tank would also have a vent in the top like any fuel tank.
The idea about a coolant exchanger is good, but it adds to the complexity of the system, and the boiling temp of any coolant will be lower than oil, unless of course you use oil as the exchange medium, at which point seems a bit redundant.
Ask questions. Throw ideas.
Don.
EDIT: I just ran back outside and touched my exhaust tip. I was driving the truck 10min. ago, and the exhaust tip is barely warm to the touch. It couldn't have been at 500F 10 minutes ago. I came off the interstate, drove 2 miles, then drove gently into my apartment complex. No cool down time. I'm going to buy an IR pyro and start measuring pipe temps. I'm sure there's an area that is around 200F or so. If you find the perfect area, the valve will seldom close and you will never have stagnant oil in the coil.
That is exactly what I am doing now on my setup. I have a copper tube wrapped around the exhaust pipe about 4 times at the Trans x-member, then help tight to the pipe with clamps. I did take an infrared temp reading at that point before had and it read about 140* after about 15 minutes of idling. I am not sure what the temp goes up to when under load, but so far the Nylon tubing that I have hooked to the copper has not melted, so it can't be that excessively hot. Seems to work well. I do not have my tank heater in yet, and the truck is cold blooded in the morning on a veggie startup, but give it 5-10 minutes and all is well. [img]/ubbthreads/images/graemlins/grin.gif[/img] I do need to get an additional boost pump to help the factory pump though as I am losing fuel pressure in higher pwr settings than stock.
Hey, do me a favor and drive the crap out of that thing with the EDGE cranked, pull over and shoot the pipe near the muffler. You'll be my best friend. I'll send you a couple 4 gallons of diesel. That should get you through the winter. [img]/ubbthreads/images/graemlins/wink.gif[/img]
Is your WVO in an in bed tank? I'm so envious of the pre '99 guys. Dual tanks would rock. I sometimes wish I had my '97 back.
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Hey, do me a favor and drive the crap out of that thing with the EDGE cranked
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So you want me to go out and abuse my truck and risk getting pulled just for some temps? [img]/ubbthreads/images/graemlins/confused.gif[/img] Alright, cool. I have been looking for an excuse to go thrash the EDGE. I have some pretty cool results also, but that is another post. Suffice to say I knocked off almost 5 seconds off my stock 0-60 time [img]/ubbthreads/images/graemlins/eek.gif[/img]
Anyway, temps. After a smokin 0-60 run with EGT approaching 1300, I pulled over about 1/2 mile later and read
274* right before muffler
350* right after muffler
and where I had my coils at, the trans x-member, the pipe registered 224*, and the copper registered 207, of course I was running on diesel at this point for time trials, so there was no circulation in the copper. Hope that helps, got to tuck in the little girl [img]/ubbthreads/images/graemlins/smile.gif[/img]
Oh yeah, I expect my free diesel next day fedex [img]/ubbthreads/images/graemlins/grin.gif[/img]
Sweet, I figured you'd like my idea. Looks like if we put a 200F switch on the tank, the valve will rarely, if ever divert the flow. I'm talking about heating a 20+ gallon tank to 200F. I think the tank will cool enough so the valve will be off rarely.
I'm surprised the pipe was hotter after the muffler. Might have been the reconvergence of the hot gasses back into the pipe or something. Well, sounds like the exhaust idea is a good one. The other option is a single wrap for temp maintenance, and a multiple wrap for getting the stuff hot initially. The diverter valve could be connected that way.
Fordnut, I took the fuel to the FedEx depot in four 1 gallon tin buckets. They wouldn't take them. Any ideas?
I would say just do the copper wrap, and leave out the valve. Let's try to keep this as simple as possible. Less crap to go wrong. the Flash Point of canola oil is around 470*f, [img]/ubbthreads/images/graemlins/shocked.gif[/img] so I don't think getting too hot will be a problem.
Yeah, I was kind of surprised to see the after muffler temp higher also, but it makes sense. the muffler is just a big heat sink, and the excess collected heat will be be blown on the direction of exhaust flow
I don't suppose you at least covered the buckets of Diesel with Duct tape first did you? [img]/ubbthreads/images/graemlins/wink.gif[/img] I don't know what there problem is, diesel is not very flammable anyway [img]/ubbthreads/images/graemlins/shrug.gif[/img]
Now this is a great idea. I know a motersports engineer that has been developing a heat exchanger that is part of your exhaust system. Now on his 7th generation he is ready to start selling them. The real key to getting veggie to burn in your diesel is viscosity. As it turns out SVO needs to be at about 170 deg to have the same viscosity as diesel. Another factor is water in the veggie. You can boil it out but to do that the veggie needs to get to 220 deg. Lets see you try that with a coolant based system. Wrapping the copper pipe is good but not good enough. When you burn veggie at a lower temp you get more gumming and ware on your engine but when you burn it at 150-180 deg. its actually better for you engine. Please note: do not send 220 deg. veggie through your injectors!!.
oh and to answer another question about the heat of the veggie in the converter: No you don’t have to worry about that too much. When the pump is shut off the veggie still creeps through the exchanger.
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Wrapping the copper pipe is good but not good enough. When you burn veggie at a lower temp you get more gumming and ware on your engine but when you burn it at 150-180 deg. its actually better for you engine
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Actually in the 7.3 the feul rails are actually cast into the head, so the fuel is without a doubt engine temperature when it goes through the injector [img]/ubbthreads/images/graemlins/smile.gif[/img], my biggest concern was getting it warm enough to allow the factory pump to pump it well enough to maintain propper pressure, and able to pass through the filter without plugging it up. So far I have noticed that anything above about 110 filters fine [img]/ubbthreads/images/graemlins/wink.gif[/img]
I can see using a pump (such as a Holley electric fuel pump) to push the veggie through the heater loop going around the exhaust, through a filter and on to a solenoid... and to the engine. But, what happens to the residual veggie oil in the exhaust heater loop if you run out of veggie or turn off the pump? I fear cooking that bit of remaining oil left in the coils. The tank is higher than the exhaust. Maybe a lift pump with a check valve so that it doesn't back flow back to the exhaust pipe coils?
What about using a fuel pump off a hot water pressure washer? These are for pumping diesel or kerosene. Cheap and easy to replace.
I can even see creating a circulation kidney loop where we pump veggie through the heat coils and filter continuously. Think of it as the same thing as a by-pass oil filter. Each pass polishes the veggie a bit more and more.
Todd T
__________________
2002 F-250 Lariat, PSD, CC, short bed, 3.73, auto tranny, Line-X bed liner, AFE Filter, HX crossover, intake heater delete, Evans NGC+, Dieselsite 203 thermostat, coolant filter, Amsoil by-pass filter, Schaeffer's synthetic blend tranny fluid, Bob Riley's tranny filter, Velvet Ride shackles, Rancho 9000 shocks with in-cab adjustment, 60 gallon aux tank for burning heated WVO, burning veggie since fall of '04.
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Well, I don't have an infrared pyrometer, but I would guess the exhaust at the rear of the truck and the muffler housing shouldn't be over 250F-300F.
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well my truck Idles about 250-300 degrees so the pipe is not that hot back towards the muffler and when running hard around 1100 degrees the elbow right under my stack gets hout enough to melt thru an igloo cooler lid [img]/ubbthreads/images/graemlins/shocked.gif[/img] [img]/ubbthreads/images/graemlins/phoney.gif[/img] [img]/ubbthreads/images/graemlins/shrug.gif[/img]
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So, if my guess is correct the hottest the oil in the tube would get would be around 250F or so. It should be stable at that temp. Don't fast food fryers run at temps higher?
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the WVO my buddy can get comes out of the fryer at 425 degrees
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