VWDiesel.net The IDI, TDI, and mTDI source.
Engine Specific Info and Questions => IDI Engine => Topic started by: jtanguay on February 20, 2009, 11:36:19 am
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does anyone have the low down on the optimal diesel temperature??? i know some TDI's have fuel cooler/warmers to maintain optimal fuel temps...
anyone with VAG-COM knowledge of optimal fuel temp range?
thanks!
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just did some reading... apparently it is 145F(62.78C) to 155F(68.33C) ???
that sounds a little bit hot... i thought cold wasn't so good, but i thought the right temp was closer to 15-20C.
anyone have any thoughts on this? i might build a controller to test this out.
http://www.freepatentsonline.com/4343283.html - this site is now saying "within 140° F. to 150° F." which sounds more like it to me.
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I have no idea but please keep looking and post what you find :)
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well, the volume of fuel shouldn't change much based on temperature, but the viscosity will, so I suppose that hot fuel will atomize better due to its lower viscosity, to the point of diminishing returns of course.
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What about the viscosity of the fuel changing the fuel pump timing?
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that too, there is probably lots at play that we can only guess at.
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(http://www.ross-tech.com/vag-com/cars/applications/tdi-timing.gif)
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Sooo... this really makes me want to test out a fuel heater/cooler now :) does anyone know what the measurement of advance is? is that degree's? what is the relation between that and in 0. mm or does it matter? and the temp is obviously in deg F right?
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I can't say exactly what the optimal diesel temp is , but i do know that the temp you want it is below what you want to run WVO. I would also imagine that in an IDI pump it probably change it a bit but not much of an effect as in a TDI because of the fuel temp sensor in those pumps. I will also try to dig and find more precise info.
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what i would like to know: is there a direct relation between fuel temp and injection timing? (without ECU control)
my best guess would be yes, but i can't see any useful applications of varying the fuel temp by much... (possibly cooler for more performance-50C, and hotter for fuel econo-60C???)
to properly read the above graph, does that represent the timing limits for the ECU? meaning that the red line indicates FULL advance and the blue means FULL retard? that could possibly help people with mTDI pumps. i'd still like to see a timing graph to plot timing vs engine rpm though... :wink:
(http://wiki.obed.org.uk/images/6/63/Skoda_Timing.gif)
(http://wiki.obed.org.uk/images/7/72/Skoda_Timing2.gif)
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that is for a 1.9TDI skoda engine code AGR (should be good for TDI's right?) any way of measuring injected quantity on an IDI pump other than with a test bench? and is that something that can be made variable on a mech pump, or no?
i would still like to see timing vs rpm vs fuel temp :)
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At higher temperature, the hydraulic head will also "leak" more diesel, resulting in a smaller amount of injection quantity and retarded timing.
I would suggest you to install an exit valve from a Tdi-e pump. There is a higher flow at high RPM and full load, resulting in more stable temperature.
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that is for a 1.9TDI skoda engine code AGR (should be good for TDI's right?) any way of measuring injected quantity on an IDI pump other than with a test bench? and is that something that can be made variable on a mech pump, or no?
I have Lucas injectors in my 1.6td, one of them has the pintle lift sensor that the TDI's use.
one could measure injected quantity like the ecu does, by measuring the time the pintle opens.
it can barely be seen on this pic:
(http://naotefiques.no.sapo.pt/DSC00391S.JPG)
notice the thin wire and plug on the second injector, I have to use a 1.9 pipe for that injector as its the same height as a 1.9.
some BMW engines also had that injector, made by Bosch.
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At higher temperature, the hydraulic head will also "leak" more diesel, resulting in a smaller amount of injection quantity and retarded timing.
I would suggest you to install an exit valve from a Tdi-e pump. There is a higher flow at high RPM and full load, resulting in more stable temperature.
interested on the differences in using different exit valves on a IDI engine :D
why do the tdi ones flow more at higher rpm?
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any other input?
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Seems to me that after a certain length of time running, the pump is quite warm to the touch, what with being bolted to a hot engine... I'll hit mine with the infrared thermometer when I get home from work.
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I can't say exactly what the optimal diesel temp is , but i do know that the temp you want it is below what you want to run WVO.
Yes, we've found that WVO needs to be a minimum of about 180F in order to run well.
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I can't say exactly what the optimal diesel temp is , but i do know that the temp you want it is below what you want to run WVO.
Yes, we've found that WVO needs to be a minimum of about 180F in order to run well.
but 200+F fuel can't be good for the pump??? a way to regulate temperature would really help with fuel economy and pump longevity.
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The reason for the temp in WVO is to reduce viscosity. I asked the Detroit Diesel tech at work the question on diesel fuel temps today. He couldn't give me a definite number but said it should be about room temperature.
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The reason for the temp in WVO is to reduce viscosity. I asked the Detroit Diesel tech at work the question on diesel fuel temps today. He couldn't give me a definite number but said it should be about room temperature.
hmmm seems like not too many people pay attention to fuel temp.
the controller i'm envisioning will be capable of +-1.5C temp range, so the car performs as it should (year round). it will be able to hold those temps regardless of the outside temp. i just need to develop circuitry that will not only control it, but something to shut it off in the event that it sucks too much electricity (it will be around 350 watt, and most of the energy will be used when the temp is -0) so this thing will be very quick reacting. i'm also contemplating a system that will switch modes from 100, 200 and 350 watt in the event of charging system overload (especially TDI's with the glow plug heater, and N/A's with the pewny 50 amp alt)
the system would also have two power inputs. one would be setup for diesel specific temp (adjustable) and WVO specific temp (adjustable) so you could easily adapt it to work in conjunction with your veggie setup by using the power source to control a relay which in turn controls the mode on the fuel temp controller.
i'm slowly learning about circuitry, so we'll see how far i can get :lol:
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Jtanguay: The circuitry involved here is relatively simple, and I would be more than happy to look over/contribute to your design. I suddenly have some free time, so my projects have started again!
From your power specs I'm assuming you will be utilising some form of peltier setup? I'll throw a few more ideas out aswell. Will need a fair area/coverage to actually produce some effect on the temperature delta, perhaps using an OEM based cooler as a platform? Would need some testing aswell to see what flow rates we are dealing with here to get an efficient design. Would need two temperature inputs, one of incoming fuel temp and one of outgoing. Obviously a lot of the factors depending on fuel temp stability extend to how much of a reserve (the fuel tank) you have.
That was just a quick brainstorm, but a very simple microcontroller could be used, or, you could even just go with some simple analog circuitry utilising a couple of comparators.
Just ideas :)
-Gavin
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The Duramax diesels use a fuel cooler also. It is located in the return line going back to the tank. This makes sense since the fuel pressures of these common rail set-ups see 20,000+ psi. Just a bit of input if it helps. :)
BTW, the DB rotory pumps use an orfice type of vent to regulate the transfer pressure variations caused by viscosity and RPM (if it wasn't regualted the pressure would continue to rise as the RPM's do). The viscosity differences would be caused by temperatures. There is a chart for this but they are in my factory manuals at work. 8) I will try to get a copy of this if I can.
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Jtanguay: The circuitry involved here is relatively simple, and I would be more than happy to look over/contribute to your design. I suddenly have some free time, so my projects have started again!
From your power specs I'm assuming you will be utilising some form of peltier setup? I'll throw a few more ideas out aswell. Will need a fair area/coverage to actually produce some effect on the temperature delta, perhaps using an OEM based cooler as a platform? Would need some testing aswell to see what flow rates we are dealing with here to get an efficient design. Would need two temperature inputs, one of incoming fuel temp and one of outgoing. Obviously a lot of the factors depending on fuel temp stability extend to how much of a reserve (the fuel tank) you have.
That was just a quick brainstorm, but a very simple microcontroller could be used, or, you could even just go with some simple analog circuitry utilising a couple of comparators.
Just ideas :)
-Gavin
sounds good! the 350 watt peltier junction is ideal for this situation. i'm considering running the fuel heater/cooler in a closed loop from the fuel tank. a small solid state fuel pump will ensure about 5-6 psi in the closed loop, so as motor burns the fuel, the pump will introduce more fuel into the loop. this will lessen the load on the fuel heater/cooler, and also give better cold/hot starts. if any of you have doubts about this setup... don't. although i'm not currently running like this, i will be in the future. a friend of mine is running like this, and he's never had better cold starting, and running. come summertime the fuel will get too hot though, and thats where the fuel cooling function will really come in handy :)
i've been thinking of using resistors to limit the current draw. the problem is finding some that are economically priced. the resistor on the rad fan would make a good candidate for testing, but it is a little bit expensive... i have found some resettable fuses which would handle the load, and 'pop' if the peltier sucked too much power, and then it automatically resets itself, very cool!
i think a big problem will be getting a big enough heatsink without making the unit so big it won't fit anywhere :lol:
i'd really like to go with a valve system that would send fuel through a heatsink to cool it, but electronic valves are so expensive, and very prone to breaking...
please get a copy of the viscosity differences caused by temps chart if you can AdAm84 :)
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I suggest that you first find out what temerpature of your fuel is at the moment.
Perhaps it's a good idea to use a custom heater with one or 2 glowplugs. There are enough fuel coolers I think (haven't looked into that.
I got a 12v digital temperature controller with relay output. You can set the temperature where you want to switch the magnetic valve (2/3-way) and this way you can cool or heat the fuel. Also turn on the heaters when then the relay is switched.