fred1
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![[*]](./images/onepoint9/default_icon.gif) posted on 19-11-2009 at 06:26 PM |
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Heat exchanger and a blend
I would like to use a heat exchanger and heat a blend. The blend would be 95% veg, 5% petrol, 5% diesel or there abouts. I use a standard single
tank.
I have heard that there may be a problem with vapour lock.
Has anyone any experience of this?
Is there a percentage of petrol that would be OK?
Is there a max temperature that the mix should be heated to avoid vapour lock?
I know I could reduce the veg percentage and increase the diesel and cut out the petrol all together. It’s just that a small amount of petrol makes
the veg so thin
Anyone any thoughts?
Thanks
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Olivier
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| posted on 19-11-2009 at 06:44 PM |
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It work well for some, on my car even at 5% only petrol I was having bother with the bubbles/ air lock.
I guess the best is try and error .
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McDuff
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| posted on 19-11-2009 at 08:04 PM |
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I gave up using petrol as my system is very efficient (even just 5% at 70mph gave vapour lock, lower speeds ok), I now use diesel/wvo/cetane booster
Ford Ranger 2 door 2.5td 4x4
Ford Ranger 4 door 2.5td 4x4
Current mix of 3-4ltrs Diesel, rest wvo to 20ltr mix filtered to 0.1micron
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jhanananda
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| posted on 20-11-2009 at 03:35 AM |
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Since vapor lock is a danger when blending gasoline (petrol) with vo on a heated fuel line, or using a heat exchanger, then I believe it is wisest to
blend with diesel instead of gasoline. However, the findings of the blenders suggests that a heated fuel line, or a heat exchanger, is unnecessary.
The findings of the blenders is blending 20% gasoline (petrol) with VO at 80% will keep the fuel blend liquid below -10C and will start and run fine.
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pwbadi
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| posted on 20-11-2009 at 08:54 AM |
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I ve had issues with10% petrol. But I am still using it coz I have around 200l of WVO already blended. And no more fresh WVO.
My car has an in built heat exchanger which operates with the heater matrix.
When ever the engine is above 85C I tend not to use the heat exchanger, simply by turing the heather matrix to cold. Seems to work.
BMW320d(E46)ESTATE on B100 15kMiles .
Merc190D-100%WVO-10kmiles-No Mods
206Hdi on 100%BIO- 4000 miles so far
206(Lucas)-B100 5kmiles now sold- Kept me very busy- Very unreliable
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fred1
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| posted on 20-11-2009 at 08:25 PM |
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Hi again
As we know it’s the hot petrol that causes vapour lock
Has anyone used something like a thermostat type valve to control the heat, to just below the temp that petrol vaporises, maybe about 65C degrees?
If this would be possible we would have the best of both worlds
How veg and petrol that will make it thin
Another possibility would be to position the heat exchanger in an exposed position so that it doesn’t get too hot
Any thoughts?
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fred1
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| posted on 20-11-2009 at 08:28 PM |
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Above should read
Hot veg and petrol that will make it thin
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McDuff
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| posted on 20-11-2009 at 10:32 PM |
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If you want a heat exchanger in an exposed position it would be cheaper not to have a heat exchanger as the results would almost certainly be the same
Ford Ranger 2 door 2.5td 4x4
Ford Ranger 4 door 2.5td 4x4
Current mix of 3-4ltrs Diesel, rest wvo to 20ltr mix filtered to 0.1micron
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jhanananda
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| posted on 21-11-2009 at 02:59 AM |
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If one was interested in combining heat and blending with gasoline (petrol) then one we want to regulate the heat below 120F (50C).
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Perfo
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| posted on 21-11-2009 at 05:57 AM |
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Generally use one of the other (depending on the set up) you could possibly get round any vapor lock problems with temp control and a well designed
fuel route. Do some simple tests to find out what viscosity you're looking for and pick the best way for you to achieve it.
The L200 (4d56 2006) seems to be running nice on WVO/Dino blend upto 90% runs well but a bit more reluctant to start. All good so far.
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pwbadi
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| posted on 21-11-2009 at 09:13 AM |
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Yesterday I did 300 miles with just 5% petrol with no issues. The engine temp was always above 85C. Bringing the percentage of petrol from 10 to 5 has
certainly helped.
You can setup a heat exchanger to operate with a thermostat can't you. ie just like he normal thermostat
BMW320d(E46)ESTATE on B100 15kMiles .
Merc190D-100%WVO-10kmiles-No Mods
206Hdi on 100%BIO- 4000 miles so far
206(Lucas)-B100 5kmiles now sold- Kept me very busy- Very unreliable
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Bottleveg
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| posted on 21-11-2009 at 11:00 AM |
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Would it make any difference if the vehicle had a tank return instead of looped?
Where does the vapour lock happen? Would a facet pump cure the problem?
(Mark) 1998 Ford Escort 1.8TD.2nd Lucas pump. Twin tank. 100% UVO. Now sold.
1997 Astra 1.7TD Isuzu. 100% UVO. Dog rides shotgun. 1999 Merc Sprinter 310 2.9Di Twin tank 100% UVO. Dog needs a lift to get in, and ride shotgun.
WMO central heating. Lister 8/1 SOM to be run on WMO.
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jhanananda
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| posted on 23-11-2009 at 04:39 AM |
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Bottleveg, vapor lock is most likely to occur on the negative side of the fuel pump, because the pressure will be lower there, which will encourage
the lighter fractions in gasoline (petrol) to volatilize. Knowing that one could chose to put most of the heat on the positive side of the fuel pump,
which will drive up the vapor pressure of the fuel, not lower it.
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Bottleveg
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| posted on 24-11-2009 at 01:02 AM |
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Hello jhanananda, What side do you refer to as the negative side, the feed to the pump?
If the return is looped then is it all negative?
Apparently the old Rover V8’s cold suffer from vapour locks, I’ve had a few of them and never experienced it. The cure was, so I’m told, fit an
electric pump. That’s why I mentioned the possible facet pump cure.
What happens when this vapour lock takes place? I don’t think I have ever experienced it.
(Mark) 1998 Ford Escort 1.8TD.2nd Lucas pump. Twin tank. 100% UVO. Now sold.
1997 Astra 1.7TD Isuzu. 100% UVO. Dog rides shotgun. 1999 Merc Sprinter 310 2.9Di Twin tank 100% UVO. Dog needs a lift to get in, and ride shotgun.
WMO central heating. Lister 8/1 SOM to be run on WMO.
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jhanananda
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| posted on 25-11-2009 at 03:06 AM |
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Hello Bottleveg, yes, the negative pressure side of any pump is the inlet side, where it pulls a relative vacuum to pull in whatever fluid it is
pumping. But, no, a looped return will not reduce the negative pressure on the input, because a looped return should go to the fuel tank and not to
the intake of the pump or it could result in other problems, like not allowing air to be purged from the fuel line.
While replacing a mechanical diaphragm fuel pump with an electric one might very well reduce the likelihood of vapor-lock, nonetheless, doing so also
reduces the fuel flow and delivery pressure, which can undermine the injector pump, so I prefer keeping my mechanical diaphragm fuel pump as the
primary fuel pump. But, then I do not have a vapor lock problem because I do not heat my fuel line. I see no reason to do so when I blend gasoline
(petrol) with my VO and the temperature almost never drops below freezing here.
[Edited on 25-11-2009 by jhanananda]
[Edited on 25-11-2009 by jhanananda]
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