Placement of heat sources

[ToddT]

I'm replumbing my 2002 PSD veggie system from a Greasel style setup using the stock fuel pump and fuel filter for both diesel and veggie to an FN74/Vegistroke style system incorporating a separate fuel pump for the veggie.

My fuel tank is a 60 gallon tank/toolbox combo from Northern Tools. For an in-tank heater, I fabricated a heat exchanger that is in essence a Hotstk surrounded by a coil of aluminum tubing with coolant running in it. I use 3/4" heater hose, HOH arrangement. I also use 1/2" heater hose wraps around the filters.

I have a 16 plate FPHE and a Fattywagon nichrome heater wire kit that I've never installed. Suggestions on where to place each of these? I'm leaning toward mounting the heat exchanger after the Mallory 110FI fuel pump and under the hood. Then, use aluminum fuel line plus the nichrome wire heater feeding the fuel from there to the manifold just prior to the heads. This way the fuel has a means to heat up in an area not affected by the HOH coolant heat.

Suggestions?

Todd

[hheynow]

I believe the Mallory fuel pump is not self priming and must be installed lower than the fuel tank.

[Spotty]

don't attach aluminum lines directly to the engine. The vibrations will break the line at the fittings. I learned about this at 4am on the highway.

[Abbey]

I made that mistake of using the fn system and after going through two of the 300 dollar electric pumps I switched back to the mechanical pump and have never had a problem again ( knock on wood) I don't know if you can put a mechanical pump on a 2002 but I put one on my 1998

[Monte1]

The logical thing to do is to place any heating device in the place it will do the most good, i.e. where it will raise the temperature of the wvo the most. The hottest coolant is that coming out of the engine and heating the fuel in the HIH system. That's why the hottest coolant heats the warmest wvo in this counter-flow system. The limit of the temperature in a HIH system is the temperature of the coolant. The problem is that as the fuel oil gets warmer, the efficiency of heat transfer decreases because the difference in temperature between the coolant and the wvo becomes smaller. So, while we try to get the temperature up as high as possible using "free" heat from coolant, some additional heat is required in some systems. All this would lead one to conclude that the order of heating that would produce the highest wvo temperature would be (from the IP going back to the fuel tank) would be
a. electric heat
b. coolant heat exchanger
c. fuel filter coolant heat
d. HIH back to fuel tank
e. In tank heat exchanger if used.

Since electric heat is not limited by the temperature of the coolant,
it is often used closest to the IP/engine. Sure, you can change the order of these heat exchangers by using electric heat at various points, but it isn't "free" heat like engine coolant is.

This is counter to direction of the fuel flow direction.

[ToddT]

Here's my current thinking... what do y'all think?

The main backbone of the WVO heating system will be a 3/4" heater hose coming directly off the engine and returning to a T on the heater hose line between the core and the engine (coolant return from the heater core). The center of the heating will be my in-tank heat exchanger that uses a 5/8" aluminum coil surrounding a 2" alum. pipe.

I want to keep the coolant flow rate high. It seems to me a flat plate heat exchanger would kill the flow rate. I'm thinking of adding a T on the supply side heater hose and another T on the return side heater hose. In between these tees will be a 1/2" heater hose wrapping around the fuel filter and going through the FPHE.

The fuel will be heated by the following, in order:
In-tank heater
FPHE
fuel filter wrap
HOH
optional: aluminum tubing for fuel line, with nichrome wire.

Todd T

[fordnut74]

[ QUOTE ]
I made that mistake of using the fn system and after going through two of the 300 dollar electric pumps

[/ QUOTE ] All depends on what pump you use. Believe me, the theory is sound. And since switching to the FASS pump, Life has gotten much better. People have fried the mechanical pump too. ANd when you went to the electric pump, were you still using one pump for both the WVO AND the diesel?

[fordnut74]

Todd- Man, you have been around here since nearly the begining, feel free to shoot me a PM if you want some suggestions. I will tell you that you only want the minimum heating needed in the tank. A very basic coolant heater will work fine there, like you describe. Then HOH from there to your pump. Your filter should be the last main item that your oil passes through before reaching the motor. Use an electric heating element on the filter. I use a 200 watt element on my Huge Donaldson and have seen up to 250 fuel temp into the motor. Usually about 210. Avoid the conventional HIH using copression fittings and aluminum line, you will be chasing leaks to the end of time. If you do use HIH with aluminum line, make sure to use an appropriate hose to connect to the motor, as mentioned, the aluminum will fatigue and crack eventually. If you blow a fuel line, then the failsafe design of the Fn74 goes out the window. Bottom line, don't over engineer/complicate things more that need be. Let me know If I can help you at all. [img]/ubbthreads/images/graemlins/wink.gif[/img]

[ToddT]

Thanks, FN. Yeah, I've been running grease for years.... and am still learning. The R&D scientist in me always has another idea of ways to improve. Overengineer? Me? Have you been talking with some of my local friends? Thanks for the good advice.

I never have been a fan of HIH. I like being able to inspect the system with HOH. I like your idea of 12v filter heating, too.

On a side note, I'm playing with a 115v coolant pre-heat system. I bought an 850w 115v plug-in coolant heater on eBay a while back. My plan is to add a 3-port solenoid valve on the coolant return line and jump it over to the coolant supply line. A check valve will be placed in the coolant supply line to prevent it from back flowing into the engine.

The coolant heater will be added to a side loop. In pre-heat mode, I plan on using a pump to circulate the coolant through the heater. Doing so will pre-heat the fuel. As for a pump, I'm debating on a Pony pump for higher flow (flexible impeller style) or a Shurflo diaphragm pump.

The PSD block heater is 1000w, as I recall. Add to that an 850w heater, plus a small pump and I'm beyond 15amp draw... pushing 20amps. Most timers I've seen are only 15amps. That means I won't be able to pre-heat the engine AND the coolant without going to two circuits. Anybody know of a plug-in 20amp timer?

I'm setting up for bench testing today my coolant heater and fuel flow plumbing schematic complete with four or five temperature sending units along the way. I'll post a report later.

Todd

[ToddT]

Jason, I just ordered one of your 12v heaters. Its good to finally get to buy something from you after you've helped us all learn so much about this technology.

Todd

[Abbey]

[ QUOTE ]
[ QUOTE ]
I made that mistake of using the fn system and after going through two of the 300 dollar electric pumps

[/ QUOTE ] All depends on what pump you use. Believe me, the theory is sound. And since switching to the FASS pump, Life has gotten much better. People have fried the mechanical pump too. ANd when you went to the electric pump, were you still using one pump for both the WVO AND the diesel?

[/ QUOTE ] sorry fordnut I just found this post looking back for one of my old posts I was using the stock elec. fuel pump one the diesel side and a sx pump on the wvo side .The stock mechanical pump that I put back on is still going strong!

[red5jedi]

My $.02,

Read, read and keep reading. I had a intank heater and read that this causes other problems. Well I decided to look at my coolant intank heater [img]/ubbthreads/images/graemlins/eek.gif[/img] cooked oil all over it. You only want the oil warm enough to flow so that will vary on your oil. Me, no intank heater (live in NM and good oil). Mallory pump, mine only lasted 10k miles then the seal failed and coated the inside of the pump with oil. I got a FASS pump from FN and it rocks. No stupid regulator to screw with and it has a two year warranty!! Don’t waste your money on a pump that will not last. I’ve also read that the final temp of the oil is going to be very close to the temp of the heads of the motor because the oil/fuel passes through them before getting to the injectors. Heads <160deg = oil <160deg, Makes sense. You talked about using a heater to preheat the coolant just around the HOH to preheat the oil- I was thinking the same thing but not to heat the oil but to bring the whole engine up to temp quickly, then I can switch over to oil. I use 3/8” stainless steel from Summit for a HIH system. If I did it over I would use 5/8” heater hose to make the connections much easer. Stainless is harder to work with and again if I had to do-over I would look into the price difference in FN new flex hose. To late for me.

So my system from the tank- VO pick up on the bottom, corner edge of the tank with the coolant on the outside of the tank for a little heat (no cooking)--> 2.5 feet HIH--> FASS pump with heat exchanger--> filter wrapped with heater hose--> 6 feet HIH –-> into check valves then to cylinder heads.

Rich

[drcampbell]

[ QUOTE ]
... It seems to me a flat plate heat exchanger would kill the flow rate ...

[/ QUOTE ]

There's nothing uniquely restrictive about flat-plate heat exchangers. Any device that fluid flows through will have a pressure drop. If the Hx is large enough, the flow resistance will be low enough and the flowrate will be high enough. Get a basic textbook on fluid mechanics and a component datasheet for the Hx. Figure out and tally up friction factors, and if need be, increase component sizes until you're satisfied with the total flow resistance.