Temps are now reaching 25F around here but my switchover times are not yet markedly longer than summer. Right now my injector lines are naked and I've been thinking of maybe adding electric injector line heaters. I decided to check how much VO cooling is happening from the IP to the injectors.

Sit up boys and girls! When it's cold out there, all your heating attempts prior to IP are greatly diminished on those steel lines. How many times have we been told this? Believe! The message I take home is: cover up those lines, with, anything, just something.

Unscientifically, but very convincingly, I used the grab test. You can do this too... Keep your fancy IR thermometer in your pocket. Here's how mine went:

After running many highway miles on VO, pulled over and stopped with engine still running VO. Lift the hood. Poke finger on small metal can fuel filter located on a short rubber fuel line just prior to IP, ouch! (hot, can't hold it there). Next, poke finger on metal banjo where fuel goes into IP, ouch! Pinch a delivery valve (outlet) on top of the IP, ouch! Pinch an injector steel line a couple inches away from delivery valve, ouch! Pinch the line two inches from injector.... and ho-huh... warm to the touch. Pinch the top of an injector, at the line fastening bolt, ouch! Touch anywhere on the injector, duh, ouch!

OK... a lot of heat is getting lost on injector lines by end of journey, due to cold wind blowing over them. Would injector heaters help? Yes. But probably just wrapping *anything* that insulates the lines from wind will help. Fuel is not flowing through those lines (or injectors) very fast, my car is pretty fuel efficient. I think somebody tried the math once on this forum, and basically it's a dribble down the line, no gusher.

This experiment conjures up the old arguments that injectors themselves are HOT, adding heat back into the VO.. and maybe enough heat to get the cooled oil back to target temp 170F, or higher, prior to nozzle injection. Considering how slow the fuel moves, I tend to believe it can pick up a lot of heat sitting in that injector for not-too-long. Why are we adding all this FPHE heat prior to IP again? Oh ya, to get better diesel-like compression in the pump.

Something twigged in my mind doing this experiment. Fuel sitting in the line is the shock wave delivery medium that carries the pulse causing injection. Even if injectors can re-heat VO the cooler VO in the lines may affect the delivery shock wave. I dunno, cold or hot fluid may have the same delivery dynamics (compressibility?)... But it just seems better to me, to preserve as much heat as possible in the lines, because it will act more like diesel and you'll get a better injection event if the viscosity stays close to diesel for the whole journey.

Note, the driver's side half of radiator is covered with cardboard. My temp gauge is pegged at 80C for this whole experiment.

Anyway, now I'm looking for good suggestions on wrapping the lines with different materials.

The cheapest fastest way I can think of is to use 1/4" split loom wiring harness, that corrugated looking black tubing. Keeps the wind off the line.. but not much insulative R-value. Other people must have some ideas.

look at this thread for a good source for insulation.

OK, neoprene wrap - that's a good one.
Probably on the 'thinner' side of neoprenes, maybe 3mm would do, and 1 inch wide strip.
Get a good spiral going and will have enough overlap without getting too bulky.

Challenge with any wrap: how do you secure the ends from unraveling? Velcro strap maybe.


I like wraps versus tubes, because when lines merge close together and travel in packs, you can just wrap 'em all in one go for that section.

quote:

This experiment conjures up the old arguments that injectors themselves are HOT, adding heat back into the VO.. and maybe enough heat to get the cooled oil back to target temp 170F, or higher, prior to nozzle injection. Considering how slow the fuel moves, I tend to believe it can pick up a lot of heat sitting in that injector for not-too-long. Why are we adding all this FPHE heat prior to IP again? Oh ya, to get better diesel-like compression in the pump.

I have never heard that VO should be heated for that particular reason Scott. All the research I have seen, read, or participated suggested heating VO to lower its viscosity to that of diesel fule at the point it is actually injected. The old arguments you metion always ignored the fact that diesel fuel is ALSO heated as it passes through the hot injector. So to assure as much as possible that the FINAL viscosity for BOTH fuels match as much as possible the heat that BOTH fuels pick up as they pass through the injector is "moot". The VO fuel "target temp" of 170F (or higher) is not at the bottom of the injector..but rather at the top....before it passes through the injector.

I agree that there is a lot of heat lost as VO passes through steel injector lines. Even in warm weather it makes a significant difference. Years ago..before effective injector line heaters were available..I used a variety of materials to try to reduce the amount of heat that was lost as VO passed through injector lines.

I agree that anything is better than nothing. As long as an insulating material does not rub holes in the injector line or add significant mass to them (possibly creating fatigue cracking) it will reduce the heat loss. Split silicone tubing works pretty well especially if you can find thick wall tubing. It is flexible, insulative, and not effected much by temperature extremes or diesel/VO. If you cannot find thick wall silicone tubing one can carefully cut a strip from one tube and layer it inside another full diameter split tube.

I used to have a source for very small diameter foam split tube that was just like the type commonly used to insulate copper plumbing but much smaller. Unfortunately that source chose to stop its production. This was very easy to install and increadibly effective.

I have also tried using thick foam backed tape of the type used for weatherstripping but the adhesive just does not seem to hold up long. It is not intended for the high temps it is exposed to in this application.

Yes, you are heating the oil prior to the injection pump to ensure that you don't break the pump.
Too high a viscosity and too high an rpm can cause this to occur on distributor and rotary pumps.
Inline pumps, not a problem, lubricated by (hot!) engine oil, but you're likely heating the tank and lines somewhat anyway.

You do not say what the ambient temperature was, or I've missed that (I'll read your post again) but it's been pointed out earlier by Klaus Old that in his opinion all that is really needed is insulation on the lines, perhaps, rather than ILH's per se.


Most SVO systems have heat ahead of the injection pump (necessarily, for tank, line, filter and lift pump and injection pump), and of course all engines have heat at the injector, so capturing and retaining heat along the line itself should really be inexpensive and easy to do.

The split loom idea is not bad, fast cheap easily obtained and installed...there may be other insulating materials that can also be used to good effect.

Ok, 25F. Got it. So, obviously the colder it gets the more a good insulation on the lines could be a good thing to do. There was a liquid coating someone mentioned to me a while ago. Ceramic of some sort, I think. Has anyone ever used that for any purpose? Supposed to be very effective.

Or you could add some injection line heaters

info here
http://www.fattywagons.com/



video link here

http://www.youtube.com/watch?v...ture=player_embedded


I have had good luck with my fattywagon line heater for years

good luck
Omar
www.omarsales.com

quote:

Originally posted by Scott McPhee:
OK, neoprene wrap - that's a good one.
Challenge with any wrap: how do you secure the ends from unraveling? Velcro strap maybe..

Teflon tape

Black heavy-duty zip-ties secure my ILH ends pretty well. Where the wires come out, they take a loop around the zip tie to act as a strain relief.

Cheers,
JohnO

silicone self fusing tape

quote:

There was a liquid coating someone mentioned to me a while ago. Ceramic of some sort,

Creamic and metallic coatings won't provide much insulative value.
For any material to have an insulative value its conductive values must be very low.

Of course. The products I refer are supposed to be very effective insulators, as I mentioned, and are used in industry to insulate tanks and piping. I think they'd be worth a look.

http://sciencelinks.jp/j-east/...20020402A0174443.php The energy saving by the ceramic thermal insulation coating material.

quote:

Originally posted by Edward Beggs:
http://sciencelinks.jp/j-east/...20020402A0174443.php The energy saving by the ceramic thermal insulation coating material.

This is actually a PLASTIC coating with ceramic spheres embeddd in it.

I was responding to your vague suggestion that

quote:

There was a liquid coating someone mentioned to me a while ago. Ceramic of some sort, I think.

If this is the liquid coating you meant great. A link to where the OP might get it woudl be helpful. If it is NOT the liquid coating you were referring to a link to THAT one would be just as helpful.


I don't want to get in yet another pointless pissing match with you Ed.
I think you would agree that generally speaking ceramic and metallic based coatings are not very insulative.

I did not want anyone to go out and buy one of the liquid ceramic coatings commonly available and (based on your apparrent reccomendation) assume they would provide significant insulative value. I am sure you did not intend to provide information that might lead someone to do so. As you are considered a knowledgable source..and there are a LOT of folks who might read this and assume any ceramic coating would provide good insulation for injector line I thought a warning NOT to assume that was in order.

Well this is what I settled on for now, because it's what I had on-hand.

I used split loom for the back three, temporarily. And for the front three injectors I used a dollar store windshield sunscreen, which is a very thin and almost uselessly floppy foam backed foil... but happens to cut nicely into tape-like strips that wrap. It did two wraps, the first was foil side facing the steel, then wrapped that again with foil side out, as you can see. The outer foil is very tender stuff (can rip easily) so I covered the works with strips of glass enforced tape - that kind you cannot possibly tear.

I was going to post a picture. But it's over 50K in size. Snark! Infopoop, this forum is showing its age and I'm getting weary of danalinscott whoever you are anyway, pissing in my thread... shoo! You're killing this place, man. You win.

Scott,

I don't see how getting snarky helps.

Email a copy of your image and I will shrink it so it fits on the forum.
There are "workarounds" for the limits on this forum.

Here is a good article on ceramic coatings as insulators...note this is not with any "plastic"...just a general comment on insulating via ceramics, to close off on that comment.

Ceramic as insulation

Exhaust wraps are also available, might be a possibility....

Exhaust wraps

But; I also noted at the end of this second link that they mention using foil.

Er, anything wrong with just wrapping things up in a good aluminum foil?

Cheap like borscht, easy, molds to any shape, readily available, and effective at isolating lines and injectors from wind/cold air.

As well as of course that excellent low emissivity property that makes the turkey do so well in the oven, reflective insulations work in buildings and firewalls....allows you to cook a meal, while driving, on the exhaust manifold, etc.....could likely wrap up an injection pump pretty easily, too, if desired.

I also had a dealer in frigid Alberta asking about heating a FASS pump this winter, and he's going to put on one of our little Overnighter elements and bundle up the pump, so that it's warmed a bit prior to switchover, and does not act as a heat sink. A good foil wrap would work for that, too, either just a layer or two of good quality foil, or the foil/bubble wrap stuff used for insulating water heaters.

General article on ceramic insulation paints

...seems fairly objective and is also from what appears to be a very informative site on the topic of shipping container architecture, a fascinating development that is way off topic here, but which some might enjoy checking out.

quote:

Er, anything wrong with just wrapping things up in a good aluminum foil?

The insulation value of any material is based on how low its ability to conduct heat is.
Ceramic insulation is generally used where very high heat is present sicne most materials with a lower conductivity value will melt ot burn. This is not the case with the temperatures injector lines operate at. Even very high efficiency injector line heaters tend to operate at under 400F.

If you are considering insulating injector line heaters I suggest using silicone rubber tube. It is capable of withstanding 500F easily and has a much lower conductivity than ceramic.

Aluminum foil is not the best option since aluminum has a very high rate of heat conductivity. It may be better than nothing...but does not compare with even simple rubber hose.

Rubber has a thermal conductivity rate of .16 while aluminum has a rate of from 120 to 237.

Even polypropylene tube is not a bad choice if one is just trying to insulate bare injector line. It has a conductivity rate of .12.

Polyuerethane foam is much better than either since it has a condutivity rate of .024 -.033.

Remember..the lower the conductivity rate the better a material insulates.

Insulation based on ceramic coatings has been used both high temperature and lower temperature applications. I have merely suggested that it is one material that can be considered for this application since there are a large number of products that combine ceramic microspheres in a latex carrier, forming a liquid coating, which might be easily applied and useful for this purpose.
Caveat emptor. They are not all created equal.

---
RE: Aluminum foil, and aluminum/bubble pack, etc. :

Heat is lost by radiation, convection and conduction.

Aluminum foil acts as a simple, inexpensive radiant barrier when used correctly.

Whether or not it is practical for this application can be tested, debated, and decided by the end users.

In reflective insulations, an air space is necessary. If trying aluminum foil, it should be placed shiny side facing the line, and loosely formed around the line, such that air gap(s) are created as much as possible - not wrapped tightly.

Be careful to ensure that there will never be any contact between the wrap and any electrical connections, wires, etc. , as the foil will conduct electricity and could cause a short.

In the bubble wrap insulations, the foil is bonded to the bubble wrap, which provides the air space, and this which makes a relatively thin, flexible material that is readily available and which may have greater overall effectiveness than silicone tubing or silicone tubing alone.

There is one aspect to Scott's experiment which has not been discussed, and I think a little more checking is needed before we get too "wrapped up" in insulating lines with the materials we decide are best.

That is, there is also the possibility of heat *gain* to the injector lines.
Or at least minimal heat *loss*, as the cold air entering the engine bay is balanced out by the heat of the engine itself. It's a bloody hot environment in there in summer, and pretty warm in winter, too, once things are warmed up.

Most hoods have reflective and thermal insulation under them. My van's engine is effectively inside the van, with a very well insulated hatch over it. The injector lines are right up top, near the underside of the hood, in most caes.

So, the amount of heat lost in the way he's described would be, actually, minimal, I think, with the hood down/hatch closed in a "hot" engine bay, which is when you'll be switched over to SVO.

The way to check this is of course to get some temperature readings of the injector line's immediate vicinity, while driving, with the engine warmed up, as opposed to driving, stopping, lifting the hood, and putting your hand on the injector line. I think there would be some difference in found between these two ways of checking. That's just a guess. An older vehicle with a lot of open area around the engine, you'd expect more cold air influence, "chilling" the injector line while driving.

Most never vehicles have a tighter fit in the engine bay, shrouds, hot air coming off the radiator and flowing over the engine, more insulation under the hood and on the firewall, engine covers with their own insulating materials, air dams at the front that direct air around the vehicle for better aerodynamics, and so on.

There might also be a considerable difference between what is found to be the cast for the front-most injector line and the ones further back, in a longitudinally mounted engine.