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tbird650
24th March 2012, 04:44 PM
I wanted to gather some info regarding temperatures so I'm starting the first in a series of logs.

Today, I started recording the fuel temps at my onboard filter. As many will know, I have a sock filter inside the van.
It's not loop return. It's feed by a 10mm nylon line from an exposed to atmosphere, steel tank. The return line is original steel.
Most often my blend is heavier than diesel. Viscosity appears to play a part as to how sweet the engine runs including how much timing advance.

If this log proves successful, I'll follow it up with return line and injector line logs.
Possibly a tank temp log too. Especially if I find something interesting or unexpected, I'm likely to get keener.
Currently I have only one thermocouple, so it's one reading at a time.

Some of the things I was puzzling over re temps for issues relating to blending in unheated system:

Does tank fuel level have any affect on temps of fuel delivered to the filter?
How much does ambient temps affect fuel temps?
What range of temps are possible?
Does returning fuel raise tank temps?
Does the tank itself act as a cooler for the fuel?
Do fuel temps appear to affect starting, hot or cold?
What's the real engine compartment temp?
Does the engine compartment temp or injector line temp, rise then fall after engine shutdown due to heat soak?
Do periods of idling or low speed, raise injector line temps against open road running?

No doubt there are lots of variables. Different vehicles, engines, driving habits, fuel blend ratios to name a few.
For sure, I have a few preconceived ideas as to what the temps will be... and what effects that has.

SUZUDDIS
24th March 2012, 06:50 PM
Third
Wow there are many questions.
1. Does tank level have an effect onfuel temps ? Yes I would think so but this is only going to be affected by time of running. I would think a full tank would take longer to heat from the fuel return as apposed to an almost empty tank.

2. Does ambient temp affect fuel temps ? Well I would also think yes to some degree. Obviously on a hotter day it would heat the tank and fuel faster than on a cold day.

3. What ranges of temps ? That I don't know but with your temp recordings device you might be able to post some informative info so we all get a better idea of what really happens.

4. Does returning fuel to the tank raise tank temps ? Again I'd have to say yes. It would be slow and again it would depend on the amount in the tank as to how quickly it wil rise. I only say that because with the old Cherokee that I , it had a plastic tank. You could feel the warmth of that tank. I even think it ran better when the fuel was warm.

5. Does that tank act as a cooler for the fuel ? I am only guessing but I'd have to say yes to some effect.

6. Do fuel temps affect starting ? again I'm going to say yes but I would think that during wether extremes it would be more noticeable.

7. What is the engine compartment temp ? That I do not know but again I hope you can provide info on that. I would think it would be different while driving as apposed to sitting still but also different between vehicle types as some vehicles are more efficient than others.

8. Do periods of idle or low speed raise temps as apposed to open road driving ? Again would be differing between vehicle types. My Cherokee would run hot 90 degrees while driving at 60kmr and sitting still at around 80 degrees.
My newer car runs about 80 degrees highway driving , about 70 around town stop start and drops down a bit more sitting still all with air con on. It's a 5 cyl merc 2002 cdi auto.

Wow lots of questions. Someone chime in here if I'm wrong.

Michael

tbird650
24th March 2012, 07:49 PM
Very cool Michael, thanks.
That's pretty much in line with what I reasoned as well.
I'm guessing that some of the results might surprise though. I'm wishing I had a second thermocouple so I can collect the data faster.
Maybe I can arrange something..

Re question 8. I'm referring to injector line temps, which is the unknown, although I used to have a sensor on the lines at one time, many moons ago.
What I think happens is the fuel comes through the system and cools the IP and injector lines as it passes. Once the engine shuts down, the fuel in these components raises to engine temp. The running fuel temp is possibly some double digit degrees lower then engine temp, once normal operation is stabilized.

My first reading today showed 30'C at the filter. Ambient temp 23'C. Was after 30min run with 1hr stop part way. Tank level 1/3.

Jeffrey S. Brooks
25th March 2012, 02:23 AM
tbird650, I am looking forward to reviewing your data. If I recall correctly you have had some performance issues running petrol-based blends, and I think it was speculated that your fuel line was having some vapour-lock, so it will be interesting to see if the fuel coming from your fuel tank ever rises significantly over ambient temps.

tbird650
25th March 2012, 09:26 AM
Yes, I wasn't going to speculate on the outcomes. In fact I wasn't expecting anyone to attempt to answer the questions, but thanks to Michael assumptions are put forward.
Actually, that's a good thing. And it's not that I'm looking to prove anyone right or wrong. The hope is that from facts we can learn something that blenders can benefit from.

It should be noted that during the times of performance issues the IP may well have been beginning to suffer the effects of sustained use of fuel the maker never intended!
Interestingly the IP is still the original after 6 years of my ownership. Indeed the it has never been removed off the engine block during that time!
How much the IP played a part, how much the petrol content played a part and how much the then plastic tank and fuel lines played a part is something to speculate.
I point out that the plastic fuel tank was inside the van and not subject to any cooling, as were the fuel lines.
Another interesting thing was when forum member Socrates, run diesel through the heat exchanger and reported power loss. It appears to me that designers intended the diesel fuel system to keep the fuel as cool as possible. Much appears to be done to achieve this aim.

I'm about to go for a drive, so I'm going to check fuel tank temps with spot readings before and after.

SUZUDDIS
25th March 2012, 10:22 PM
TBird

Sorry I should have read IP Lines.
I don't know how to answer that question regarding running or sitting still. I guess that having a fuel line next to the engine block while sitting still will be hotter than highway driving. BUT these are going to be variable and like I said earlier .. vehicle dependant.
I would expect a vehicle like yours being a van would have differing temps against something like a larger engine bayed utility maybe. ??

I could imagine that a vehicle running a blend of WVO and whatever else would possibly run better when the tank was warmed. Wouldn't it be easier to have an FPHE and a looped fuel line ? that way the heat doesn't leave the engine bay and is already warmed by the time it is into it's second filter pass ? You don't then have to worry about problems with growth in the oil tank when the heated oil meets the cold oil ??
I imagine most of this is already covered in the WVO SVO section as common knowledge but some true testing and reporting would be really nice to see.


Michael

tbird650
2nd April 2012, 01:17 PM
Some results that you may find interesting.

Ambient temp range during period:9'C ~ 24'C


Injector line temperatures....
Highest and lowest recorded temp: 11'C ~ 71'C
Running, normalized, warmed up temp: 40'C - 49'C
Peak temp after shutdown: 71'C
Peak Temp percent increase during test :50 percent
Duration for temp to peak after shutdown: 19min
Duration for temp to fall to 45'C after shutdown: 136mins


Tank temperature stats....
Range of temps recorded: 9'C ~ 34'C


Filter housing temp stats....
Range of temps recorded: 8'C ~ 32'C


Biggest difference between tank & Filter: 4'C

Engine bay temp....
Open road temp: 46'C
then idle & after 3 mins 60'C

Day log from 27March2012:
12'C ambient temp 7:00am, filter 14'C, tank level 70 percent @ 14'C, injector lines 16'C.
Started and drove 30kms (approx 25mins). Filter 18'C, Tank 18'C, injector line 45'C, ambient 16'C
Returned to van 7hours later: Filter 24'C, tank 22'C, injector lines 30'C, ambient 24'C

What's interesting is the time and amount of temperature peak on injector lines after shutdown. The temp spikes at approx 20min duration before slowly falling, often maintaining temps for quite some hours.

Temps of tank and filter were closely matched with a max variation of only 4'C .

The filter temp could rise above the tank at times when the van was parked in the direct sun. It's like an oven in there! A suppose a similar situation would be the case when the filter was in the engine bay.

Engine bay temps quickly spike 30 percent after only 3mins of idling.

Jeffrey S. Brooks
3rd April 2012, 02:07 AM
Thanks, tbird, this is very useful. From earlier discussions I seem to recall that your engine is a Toyota with a rotary IDI IP that is similar to my Detroit Diesel 6.2L. If that is true, then since the only elevated temperatures you recorded were on the injector pipes, which were 71c, then I would not think that petrol blends are causing vapour-lock on your engine, because the boiling point of any substance is proportional to the pressure it is under, and presumable your injector pipes are under about 1500PSI (103bar). So, your performance problems with petrol blends has to be some other cause. I have also forgotten what blend ratio you were doing, and what your source oil was.

tillyfromparadise
3rd April 2012, 11:53 AM
Hi Jeffrey,
Another point to consider is that in an IDI fuel system the fuel is not always under high pressure. My understanding is that the pressure goes up and down so there would be times when the petrol could vaporise because of the reduced pressure.

Captaincademan
3rd April 2012, 03:27 PM
Tbird,

This is awesome mate. its so good to see this really usefull data. keep it coming.;)

Like JSB says, I doubt the problem was vapour lock, because even if the pressure did reduce (which I am sure it will at some stage) and the fuel vapourise, as soon as it increases again the vapour would be forced back into solution, and the vapour lock would dissapear.

Still reckon it was caused by something else.

tillyfromparadise
3rd April 2012, 04:26 PM
It is interesting to actually look up vapor lock.

According to wikipedia

"Vapor lock was far more common in older gasoline fuel systems incorporating a low-pressure mechanical fuel pump (http://www.biofuelsforum.com/wiki/Fuel_pump) driven by the engine, located in the engine compartment and feeding a carburetor. Such pumps were typically located higher than the fuel tank, were directly heated by the engine and fed fuel directly to the float bowl inside the carburetor.
Fuel was drawn under negative pressure from the feed line, increasing the risk of a vapor lock developing between the tank and pump."

Sounds just like the type of fuel pump most diesel engines still have.

SUZUDDIS
3rd April 2012, 04:33 PM
TBird

interesting stuff. Was this experiment to test a theory ? I only ask as you have only driven 30 minutes. not having a dig , just asking.
When do you have issues ? is it the short trips to and from work or longer trips say for an hour or 2 ? Anyone here on the main land got any data recording devices for a longer trip ?

Michael

Jeffrey S. Brooks
4th April 2012, 01:35 AM
Hi Jeffrey,
Another point to consider is that in an IDI fuel system the fuel is not always under high pressure. My understanding is that the pressure goes up and down so there would be times when the petrol could vaporise because of the reduced pressure.

Like JSB says, I doubt the problem was vapour lock, because even if the pressure did reduce (which I am sure it will at some stage) and the fuel vapourise, as soon as it increases again the vapour would be forced back into solution, and the vapour lock would dissapear.

Still reckon it was caused by something else.I am inclined to agree with Captaincademan, even if the pressure in the high pressure pipes in an IDI diesel engine were to be depressurized during operation, which they should not in a healthy diesel engine, the pressure would have to rise again to 1500PSI (100bar) at the point of injection, which would re-liquify the fuel blend. Thus, tbird's performance problems have to have another cause.

However, for blending research it is extremely useful having the temperature data that he acquired. I have saved it onto my computer, for later reference. If the same data could be acquired for all diesel engine designs, then blending research could be furthered considerably.

It is interesting to actually look up vapor lock.

According to wikipedia

"Vapor lock was far more common in older gasoline fuel systems incorporating a low-pressure mechanical fuel pump (http://www.biofuelsforum.com/wiki/Fuel_pump) driven by the engine, located in the engine compartment and feeding a carburetor. Such pumps were typically located higher than the fuel tank, were directly heated by the engine and fed fuel directly to the float bowl inside the carburetor.
Fuel was drawn under negative pressure from the feed line, increasing the risk of a vapor lock developing between the tank and pump."

Sounds just like the type of fuel pump most diesel engines still have.Yes, I agree, Tilly, my engine runs with the kind of lift pump described by the Wiki article on Vapor lock. I live in a hot region where the summer time temps can rise as high as 120F (49c), and I have run blends as high as 50% petrol in my diesel engine, but have noticed no evidence of Vapor lock. On the other hand, some people on alternative fuels forums in the UK have reported the symptoms of Vapor lock when they increase the percent of petrol in their waste oil fuel blend over 10%. In those cases we find they have a heated pickup in their fuel tank.

tbird650
4th April 2012, 09:24 AM
I'm pleased the data is of interest. I haven't finished yet though. I'm most curious to know the temps of the IP and perhaps the return line temps.

Re issues? I did have power loss and hard starting but this was improved after I did a couple of things.
I increased the IP lift pressure so it runs at 140psi @ 100kph, once temps have normalized. Also reduced petrol to 10 -12%max) and added diesel at 12-15%.

Jeffrey S. Brooks
5th April 2012, 01:58 AM
It occurred to me, tbird650, that it might be useful to know how you are measuring the temperatures that you are getting. Are you using a TC placed on the point of measurement, or are you placing a TC in the fluid stream, or are you using an IR temperature measuring device? Etc.

My guess is you are placing a TC on the pipe. If so, it is not as good as placing a TC in the fluid stream, but doing so can be most difficult. So, in that case it would be useful to insulate the pipe or section very well, and about a foot on either side of the TC to reduce the influence of heat loss on the TC and object as the vehicle is driven. Also, the TC might need insulation along its length as well to reduce conductive losses.

tbird650
5th April 2012, 08:40 AM
It's a thermocouple (TC) clipped on and wrapped in insulation.

Am hoping to swap to IP temp monitoring in next few days. I'm speculating that the running temps won't be as high there and the heat soak won't be either. I could be wrong though.

smithw
5th April 2012, 09:50 AM
My 2cents
I used to have a falcon, powered by an LD28 nissan, (dont laugh) It used to do this odd thing where if you parked its nose up a steep hill the fuel in the pump would drain back into the tank, and then it wouldn't start. is it possible that in some vehicles with blends that the petrol is vaporising in the pump pushing the fuel into the tank, and then its hard to start? and off course when the engine cools down the fuel goes back into solution and draws the fuel back into the pump. I realizes the primer pump on the filter should stop this but the valves in these are often leaky, and rotatory IPs have nothing to stop the fuel leaving the pump out the inlet. T bird, if you measure your pump pressure when the engine is off I think you will find it reads zero, maybe you could disconnect the inlet hose after a hot run, and see if it pushes the fuel out of the pump?

tbird650
5th April 2012, 11:56 AM
smithw
Thanks for the conversation and for bringing up the interesting points.

nose up a steep hill the fuel in the pump would drain back into the tank
I've heard of this happening.

draws the fuel back into the pump
I've seen this happening. Many moons ago, I had clear polyethylene line as the IP return so I could monitor the flow, etc. Also I had a valve to allow loop option.
Before long I realized that once the motor shut down, the fuel was being drawn back through this line toward the IP. Possibly is was because the fuel temps were falling and contracting in the IP, etc.

primer pump on the filter should stop this but the valves in these are often leaky
I had a situation where the primer diaphragm was leaking so I removed it, capping the housing off. I was able to see these valves and clean out the chamber. I understood the value of the non-return valves so when I decided to go with filter sock filtration, I simply hollowed out a spin-on element so I could still have the benefit of the non-return valves.

pump pressure when the engine is off I think you will find it reads zero
Agreed, it has to,as it can't hold pressure with they way the return line banjo bolt lets pressure bleed through.

see if it pushes the fuel out of the pump?
I could be wrong here, but I was thinking the fuel would be drawn back toward the tank by residual vacuum and this was addressed by the non-return.

I looked at the vent valve in the tank a couple of months ago. Another piece of the puzzle became clear once I studied this. It allows a small amount of vacuum or a small amount of pressure, but once pressure or vacuum exceeds the set limit, it's allowed to vent. This would also account for the "rush of air" when you take the cap off on a Toyota at least, but probably common to Jap diesels.

Jeffrey S. Brooks
6th April 2012, 02:08 AM
It's a thermocouple (TC) clipped on and wrapped in insulation.

Am hoping to swap to IP temp monitoring in next few days. I'm speculating that the running temps won't be as high there and the heat soak won't be either. I could be wrong though.Thanks, tbird650, your setup seems reasonable

tbird650
30th April 2012, 02:48 PM
Hi all.
Sorry, I haven't managed to start the logging of the IP or return line temps as yet.
I've looked at the issue a few times and the problem is accessibilty on these vans (as any Hiace owner will tell you).
I need a plan to clip the TC onto the IP. There's too many things in the way for it to be easy.
I havent forgotten but will get to it as soon as possible.
Thanks

Johnnojack
5th May 2012, 12:38 AM
tbird said" I had a situation where the primer diaphragm was leaking so I removed it, capping the housing off. I was able to see these valves and clean out the chamber. "
I have had this happen 3 times now, seems the daiphragm material can't take bio.

Captaincademan
5th May 2012, 09:24 AM
I just replaced my second primer pump with a walbro electric pusher and a cav filter assembly without the manual primer. Your right JJ, they don't like Bio.

tbird650
5th May 2012, 10:46 AM
I haven't used bio but I wonder, could the issue be from any leftover methanol content?
:confused:
Methanol I have used, but sparingly and only as a injector cleaner ingredient.