Warmed fuel

[onegammyleg]

Originally Posted by Brock

Hey this is common practice for diesels. They do it more because the fuel likes to be warmer so they pass the fuel past the oil with a heat exchanger

Warming for diesles is because the fuel can thicken up and freeze at quite ordinary temperatures , whereas , petrol wont.
Cold weather is a problem for diesel fuel as it can begin to solidify below ?7 deg C.

You can get big electric fuel line warmers which will allow diesels to start in -40C weather.

A diesel may have a combination of tank and fuel line heaters.
They may be electric , water heat or oil heat powered , with the prefernce of passive devices with no moving or electric parts.

[cfg83]

diamondlarry -

Originally Posted by diamondlarry

I just sent them an email requesting info for their products. Could be interesting.

One thing I did notice was that in a picture of the system I looked at a loooooongggng time ago, there was a "bypass valve" that would allow you to turn off the system if it was running too hot. Sooooooo, it was a more flexible solution.

CarloSW2

[onegammyleg]

As far as the EPA is concerned there has been no FE improvements obtained with any fuel preheating devices in gasoline cars. (and there has been many)

[GasSavers_Brock]

Originally Posted by onegammyleg

Warming for diesles is because the fuel can thicken up and freeze at quite ordinary temperatures , whereas , petrol wont.
Cold weather is a problem for diesel fuel as it can begin to solidify below ?7 deg C.
You can get big electric fuel line warmers which will allow diesels to start in -40C weather.

Well with the coolant heaters only you wouldn't think you would get any heat to the fuel right away. Of course it does use the glow plugs as well to warm things up on starting. I have started at -20F or -28C with just a 20 second glow plug cycle. It's loud on startup, but after a minute or so it quiets right down, I am told that is mostly because of retarded timing since its so cold.

So I can't image they warm the fuel in the middle of summer if it will run at -20F without heat on startup. It must have something to do with either FE or maybe emissions?

[onegammyleg]

Put a glass of diesel in your freezer ,, it will go thick.

If you started it up at -28C its likely that the fuel in that part of the line closest to the engine was still liquid.
By the time the heaters had started to get hot (less that 1 minute with an oil heater) the coldest fuel in the line would have been warmed.(at idle fuel flow rate is low)

if your car had have been kept at -28C for many days I doubt i would have started so easily.

[GasSavers_Brock]

I hate to tell you but a LOT of people in Canada and Alaska use the diesel TDI's, the same car as I have and have no issues with them starting at temps like this. As a matter of fact there is a story about a TDI’er when work let out at -40F that the only car that would start was his TDI

Modern winterized diesel doesn't turn to gel like it used to. Granted it get thicker, but there is no way if it was gelled the pump would suck it out of the tank through the lines and fuel filter to the engine and unless I could drive home on the fuel in the engine compartment it wasn't gelled.

Again my point to all this is they must be warming the fuel for some other reason other then making the fuel pumpable or burnable. It has to do with FE or emissions in some way.

[GasSavers_Ryland]

it's less work for the pump to pump thiner fuel, VW's after somewhere around 1990 have an under hood filter that has a built in re-curculation valve that is thermostaticly controled, so that as long as the fuel is below a temp, the fuel filter and fuel pump (on the engine) re-curculates fuel between the fuel filter and the pump to keep it warmer, only drawing more new fuel in from the tank as fast as it's burnt by the engine, it's a fasinating extra little bit on the fuel filter, and an extra hose, it would be nice if it was transferable to a gas engine, but a vw diesel engine sucks the fuel from the fuel tank, and gas engines with fuel injection presurize it as it leaves the tank.

[onegammyleg]

Originally Posted by Brock

I hate to tell you but a LOT of people in Canada and Alaska use the diesel TDI's, the same car as I have and have no issues with them starting at temps like this. As a matter of fact there is a story about a TDI?er when work let out at -40F that the only car that would start was his TDI .

You should write to the makers of big trucks then and tell them.
Because they use these fuel line heaters all the time as fuel jells at -7C or something like which blocks the fuel filters. (cold filter plug point)

The water content found in all diesels fuel systems is the usual cause of icing up , but the fuel iteslef will gell up.

Some fuel distributers add chemicals to lower the freezing point.
http://www.metroenergy.com/fleet/diesel_fuel.cfm

Or you can buy the additive ..
http://www.powerservice.com/dieselfu...etaneboost.asp

But..
this site is against the use of additives as they say it doesnt work as well as claimed.
http://www.aes2.co.uk/thermoline.htm


PS ,,i think you will find that your fuel filter is heated.
VW TDI's use heated fuel filters and in very cold climates come with heated fuel tanks.(costs an extra grand)

[lovemysan]

Originally Posted by onegammyleg

You should write to the makers of big trucks then and tell them.
Because they use these fuel line heaters all the time as fuel jells at -7C or something like which blocks the fuel filters. (cold filter plug point)

The water content found in all diesels fuel systems is the usual cause of icing up , but the fuel iteslef will gell up.

Some fuel distributers add chemicals to lower the freezing point.
http://www.metroenergy.com/fleet/diesel_fuel.cfm

Or you can buy the additive ..
http://www.powerservice.com/dieselfu...etaneboost.asp

But..
this site is against the use of additives as they say it doesnt work as well as claimed.
http://www.aes2.co.uk/thermoline.htm


PS ,,i think you will find that your fuel filter is heated.
VW TDI's use heated fuel filters and in very cold climates come with heated fuel tanks.(costs an extra grand)

We always just added 5% kerosine to keep the fuel from gelling. I know a lot of old truck drivers who did this in winter. Its by far cheaper than power service. I would also think that diesel in canada is a special cold weather blend. How on earth would anybody drive a diesel in canada much less alaska if the fuel was constantly gelling below -20 below. You'd be living on the edge all the time.

[Lug_Nut]

VW diesels, at least the ones sold in the North American market, do not have heated fuel tanks nor heated fuel lines. The fuel filter does incorporate a thermostatically recirculation device, but there is no warm excess fuel to flow back through if the engine doesn't start. Glow plugs are used to create hot spots within the cylinder to aid in igniting the barely flamable diesel fuel in colder weather.
The "quite ordinary" temperatures to which Onegammyleg refers is somewhere around -10F or -23C. That is for D2 or #2 diesel fuel. Adding some #1 diesel to the #2 makes a "winterized" blend which is generally all that can now be found for sale at North American diesel fuel stations where winter means sub-freezing weather. A 50/50 winterized blend of #1 and #2 diesel is good to about -40. More #1 to less #2 lowers the temperature further still.
The coldest I've personally seen was -27F (-33C). I had no trouble starting my TDI on the winterized blend of fuel. This was before I learned of biodiesel. The coldest I've seen with biodiesel or biodiesel blends is -17F (-27C) one morning when I had a B25 blend in the tank (25% biodiesel, 75% winterized petroleum diesel). Again I had no difficulties starting the cold engine.
There are generally three temperatures to be considered when discussing winter use of diesel fuel. These are, in descending order: the cloud point, the cold filter plug point and the gel point.
The cloud point is the temperature at which the fuel begins to change state. The change increases the opacity as longer chain molecules in the fuel begin to stiffen and knit or intertwine.
The CFPP is dependent on the size of the filtration media. Coarser media (or a new filter) will obviously have a lower CFPP than a sub-micron filter (or a used filter). There is some test standard that I do not know specifying the size of the media and the flow rate of the fuel used to calculate the CFPP.
The gel point is the temperature at which the fuel is for all intents and purposes a solid.
B100 soy biodiesel has a gel point of between 25 and 32F (-4 to 0 C). I hate when that happens.