Maybe = maybe not
Maybe you and your post aren't worthless.
Maybe not.
Maybe you and your post aren't worthless.
Maybe not.
spec that measures ability of oil to cool an engin
- Thread starter paulri
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It is like halves Shannow, hate to have to explain it to you but you are just so intentionally destructive sometimes. And maybe you have some 'pull' around here and can get me banned-thus APPARENTLY making you the victor in our battle as some could argue.
Here we go.
Maybe is it not clear to you that the word 'maybe' means possible or not. So, in keeping with the Shannow theme, the phrase 'maybe not' must mean not or possible.
You are like one of those staring eye posters. You need to lose your focus before you can see. It is ok. Are you still cooking pigs in your backyard?
You were apalled at what the neighbors might say if you were to take the life of a sheep or goat.
Here we go.
Maybe is it not clear to you that the word 'maybe' means possible or not. So, in keeping with the Shannow theme, the phrase 'maybe not' must mean not or possible.
You are like one of those staring eye posters. You need to lose your focus before you can see. It is ok. Are you still cooking pigs in your backyard?
You were apalled at what the neighbors might say if you were to take the life of a sheep or goat.
Originally Posted By: MolaKule
Originally Posted By: paulri
Is there a spec out there that measures the ability of an oil to cool an engine? Or is this just one of the generic jobs that oil does, that folks can't really measure?
Since I've put a full synthetic, and now a synthetic blend, in my Civic, I've noticed that the fan doesn't run loudly every time I idle at an intersection, and I'm wondering if this is something that has been tested/measured.
There is no specification to determine that.
However, a thermodynamic solution has shown that a pure synthetic base oil (no additives) has a small percentage of improvment over pure mineral oils (no additives) in terms of convective and conductive heat transfer.
I know what thermodynamics are and what a solution is, but what is a "thermodynamic solution"?
Originally Posted By: paulri
Is there a spec out there that measures the ability of an oil to cool an engine? Or is this just one of the generic jobs that oil does, that folks can't really measure?
Since I've put a full synthetic, and now a synthetic blend, in my Civic, I've noticed that the fan doesn't run loudly every time I idle at an intersection, and I'm wondering if this is something that has been tested/measured.
There is no specification to determine that.
However, a thermodynamic solution has shown that a pure synthetic base oil (no additives) has a small percentage of improvment over pure mineral oils (no additives) in terms of convective and conductive heat transfer.
I know what thermodynamics are and what a solution is, but what is a "thermodynamic solution"?
Originally Posted By: camrydriver111
I know what thermodynamics are and what a solution is, but what is a "thermodynamic solution"?
http://www.lytron.com/Tools-and-Technical-Reference/Thermal-Reference/Material-Properties
PAO has 2180 KJ/KgC, density 794Kg/m^3.
Mineral has 1910 KJ/KgC, density 875Kg/m^3
so therefore a quart of PAO can shift 4% more heat for the same Delta T as mineral...
I know what thermodynamics are and what a solution is, but what is a "thermodynamic solution"?
http://www.lytron.com/Tools-and-Technical-Reference/Thermal-Reference/Material-Properties
PAO has 2180 KJ/KgC, density 794Kg/m^3.
Mineral has 1910 KJ/KgC, density 875Kg/m^3
so therefore a quart of PAO can shift 4% more heat for the same Delta T as mineral...
I was asking about the term "thermodynamic solution".
Mjoeking, not sure why you think I would try to get you banned...
you said "maybe", I said "maybe not", in stead of "what are you babbling now ?"
Yes, I cook pig...not sure on your reference to sheep and goats, but I had a goat Curry last Thursday night, and bacon for breakfast this morning.
Originally Posted By: mjoekingz28
Maybe flash point can correlate sometimes to hear dissipation.
Instead of "maybe"..."No"
Flash point and specific heat aren't even remotely related.
Originally Posted By: mjoekingz28
I guess we should know: the heat capacity of the fluid....how much it can hold before deteriorating or burning-off.
Again, not sure what you are trying to achieve here, but pick your temperature at which you define "deteriorating", or "burning off", take the mass, multiply it by the specific heat and delta T, and you can see how much heat can be held by the fluid in the range of temperatures that you are looking at.
Not sure why you would want to do it, but as per my last post to Camrydriver, you can do it.
Originally Posted By: mjoekingz28
2) the rate at which the fluid absorbs the heat. Like I can burn a piece of bread on the stove faster than I can boil water.
Not sure what statement you are making there...the bread is a solid, and largely an insulator, and as you burn the fire side you will still be fairly cold on the untouched side.
Water is a liquid, has a very high specific heat, and can establish convective currents which distribute the heat quickly and evenly through the fluid, meaning that it's largely the same temperature throughout until the boiling point.
Originally Posted By: mjoekingz28
Like you dont want to drive hard on a cold engine.....it needs to accept the heat and it can take time..
Are you suggesting that the parts will get too hot as the oil hasn't had time to pick up the heat ?
If so, then No...if I misinterpreted it, please repeat.
Originally Posted By: mjoekingz28
3) how well it can hold/carry the het in suspension
Heat isn't carried "in suspension" like the fat particles in milk, it's an increase in the internal energy of the medium with change in temeperature.
Put it in an ideal thermos, and there will be no "fallout" of the heat, it needs to be transferred into and away from the fluid.
Originally Posted By: mjoekingz28
4) how it can pass-off/relay that heat to something else when given opportunity(s).
Part of the thermodynamic equation is the heat transfer co-efficient between what's hot, and ultimately the environment.
Dirty, fouled surfaces have a lower heat transfer co-efficient than clean bright metal...more related to the parts than the lubricant's ability to "give up" the heat. Throw in some laminar/turbulent flow, and heat transfer changes massively...for the same liquid.
you said "maybe", I said "maybe not", in stead of "what are you babbling now ?"
Yes, I cook pig...not sure on your reference to sheep and goats, but I had a goat Curry last Thursday night, and bacon for breakfast this morning.
Originally Posted By: mjoekingz28
Maybe flash point can correlate sometimes to hear dissipation.
Instead of "maybe"..."No"
Flash point and specific heat aren't even remotely related.
Originally Posted By: mjoekingz28
I guess we should know: the heat capacity of the fluid....how much it can hold before deteriorating or burning-off.
Again, not sure what you are trying to achieve here, but pick your temperature at which you define "deteriorating", or "burning off", take the mass, multiply it by the specific heat and delta T, and you can see how much heat can be held by the fluid in the range of temperatures that you are looking at.
Not sure why you would want to do it, but as per my last post to Camrydriver, you can do it.
Originally Posted By: mjoekingz28
2) the rate at which the fluid absorbs the heat. Like I can burn a piece of bread on the stove faster than I can boil water.
Not sure what statement you are making there...the bread is a solid, and largely an insulator, and as you burn the fire side you will still be fairly cold on the untouched side.
Water is a liquid, has a very high specific heat, and can establish convective currents which distribute the heat quickly and evenly through the fluid, meaning that it's largely the same temperature throughout until the boiling point.
Originally Posted By: mjoekingz28
Like you dont want to drive hard on a cold engine.....it needs to accept the heat and it can take time..
Are you suggesting that the parts will get too hot as the oil hasn't had time to pick up the heat ?
If so, then No...if I misinterpreted it, please repeat.
Originally Posted By: mjoekingz28
3) how well it can hold/carry the het in suspension
Heat isn't carried "in suspension" like the fat particles in milk, it's an increase in the internal energy of the medium with change in temeperature.
Put it in an ideal thermos, and there will be no "fallout" of the heat, it needs to be transferred into and away from the fluid.
Originally Posted By: mjoekingz28
4) how it can pass-off/relay that heat to something else when given opportunity(s).
Part of the thermodynamic equation is the heat transfer co-efficient between what's hot, and ultimately the environment.
Dirty, fouled surfaces have a lower heat transfer co-efficient than clean bright metal...more related to the parts than the lubricant's ability to "give up" the heat. Throw in some laminar/turbulent flow, and heat transfer changes massively...for the same liquid.
What do you think oil temp would be (bulk, oil in bearings, cylinder wall /ring area, and engine components itself if engine would be propelled with compressed air? I assume it would be significantly lower in bulk temp, but what about bearings?
I know OT, and irrelevant.
I know OT, and irrelevant.
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not irrelevent....
here's a paper where an engine is run motored...i.e. complete, but driven via an electric motor.
http://www.iaeng.org/publication/WCE2009/WCE2009_pp1793-1796.pdf
Cooler, but not that much cooler than with the "raging fire" that's been commented on.
If you take compressed air, and drive the piston down, the temperatures will be quite a bit lower, as the expanding gas cools as well (like a refrigeration unit)...the Indian compressed air cars apparently have some sort of heat exchanger to WARM the compressed air to reduce the cooling effect.
In the 1970s, the ROVAC refrigerant free system was going to be the next big thing.
here's a paper where an engine is run motored...i.e. complete, but driven via an electric motor.
http://www.iaeng.org/publication/WCE2009/WCE2009_pp1793-1796.pdf
Cooler, but not that much cooler than with the "raging fire" that's been commented on.
If you take compressed air, and drive the piston down, the temperatures will be quite a bit lower, as the expanding gas cools as well (like a refrigeration unit)...the Indian compressed air cars apparently have some sort of heat exchanger to WARM the compressed air to reduce the cooling effect.
In the 1970s, the ROVAC refrigerant free system was going to be the next big thing.
Shannow, very interesting, much appreciated. So main will heat to 80 *C on average operating rpm. That is a significant heat that "should not" be there. It would be interesting what happens if rig gets loaded via piston motion, similar to,a compressed air, but without cooling effect.
Originally Posted By: chrisri
Originally Posted By: dparm
Paulri, your car isn't oil-cooled, it's water-cooled.
Yes, the oil will help dissipate some of the engine's heat, but it's not huge.
Engines are oil cooled too. When low on oil, engine will overheat -if it doesn't size before that is.
Fine, there is SOME cooling performed by the oil but the engine's temperature is predominantly regulated by the coolant/water & thermostat.
Originally Posted By: dparm
Paulri, your car isn't oil-cooled, it's water-cooled.
Yes, the oil will help dissipate some of the engine's heat, but it's not huge.
Engines are oil cooled too. When low on oil, engine will overheat -if it doesn't size before that is.
Fine, there is SOME cooling performed by the oil but the engine's temperature is predominantly regulated by the coolant/water & thermostat.
Originally Posted By: dparm
Fine, there is SOME cooling performed by the oil but the engine's temperature is predominantly regulated by the coolant/water & thermostat.
And it is only cooled to the extent that the heat can be rejected somewhere. I would guess that is predominately to the head or block (and subsequently the coolant), and secondarily via the oil pan. The ability of the pan to reject heat would be highly dependent on the design and on environmental conditions.
Fine, there is SOME cooling performed by the oil but the engine's temperature is predominantly regulated by the coolant/water & thermostat.
And it is only cooled to the extent that the heat can be rejected somewhere. I would guess that is predominately to the head or block (and subsequently the coolant), and secondarily via the oil pan. The ability of the pan to reject heat would be highly dependent on the design and on environmental conditions.
Quote:
........ about 60 percent of the engine cooling is handled by the radiator and coolant, the other 40 percent (more in an air-cooled engine) must be taken care of by the engine oil.
http://www.gregraven.org/hotwater/oil/
........ about 60 percent of the engine cooling is handled by the radiator and coolant, the other 40 percent (more in an air-cooled engine) must be taken care of by the engine oil.
http://www.gregraven.org/hotwater/oil/
Air cools all engines. Coolant and oil is just a carrier of energy.
Originally Posted By: dparm
Originally Posted By: chrisri
Originally Posted By: dparm
Paulri, your car isn't oil-cooled, it's water-cooled.
Yes, the oil will help dissipate some of the engine's heat, but it's not huge.
Engines are oil cooled too. When low on oil, engine will overheat -if it doesn't size before that is.
Fine, there is SOME cooling performed by the oil but the engine's temperature is predominantly regulated by the coolant/water & thermostat.
Cylinder head and blosk's outer wall is predominantly water cooled. Most of moving parts, parts that actually produce heat via friction or are directly heated via combustion process are oil cooled. Oil/water exchanger is convenient way to keep oil temp down. Oil, like water, is just a carrier as BD pointed out earlier. Except in marine engines.
Originally Posted By: chrisri
Originally Posted By: dparm
Paulri, your car isn't oil-cooled, it's water-cooled.
Yes, the oil will help dissipate some of the engine's heat, but it's not huge.
Engines are oil cooled too. When low on oil, engine will overheat -if it doesn't size before that is.
Fine, there is SOME cooling performed by the oil but the engine's temperature is predominantly regulated by the coolant/water & thermostat.
Cylinder head and blosk's outer wall is predominantly water cooled. Most of moving parts, parts that actually produce heat via friction or are directly heated via combustion process are oil cooled. Oil/water exchanger is convenient way to keep oil temp down. Oil, like water, is just a carrier as BD pointed out earlier. Except in marine engines.
Originally Posted By: zeng
Quote:
........ about 60 percent of the engine cooling is handled by the radiator and coolant, the other 40 percent (more in an air-cooled engine) must be taken care of by the engine oil.
http://www.gregraven.org/hotwater/oil/
That doesn't give any reference to that claim.
Quote:
........ about 60 percent of the engine cooling is handled by the radiator and coolant, the other 40 percent (more in an air-cooled engine) must be taken care of by the engine oil.
http://www.gregraven.org/hotwater/oil/
That doesn't give any reference to that claim.
The only real heat that the oil "carries away" is that which it is responsible for generating in the first place, i.e. it becomes hot through shear doing it's lubricating function...e.g. some of the heat generated in mains and big ends is transferred through the block into the coolant, so clearly the oil isn't "carrying away" heat from there.
Even with piston squirters, the "cooling" of components heated by combustion is small in comparison to the oil's own heat generation.
Even with piston squirters, the "cooling" of components heated by combustion is small in comparison to the oil's own heat generation.
Originally Posted By: dparm
Paulri, your car isn't oil-cooled, it's water-cooled.
Yes, the oil will help dissipate some of the engine's heat, but it's not huge.
Sorry, incorrect. All engines are oil cooled. EX: the oil conducts the heat from piston skirts to cylinder walls where coolant carries it to radiator...
Oil galleries often run adjacent to coolant passages to help because the oil is hotter than the coolant.
engines are designed around this concept ...
Paulri, your car isn't oil-cooled, it's water-cooled.
Yes, the oil will help dissipate some of the engine's heat, but it's not huge.
Sorry, incorrect. All engines are oil cooled. EX: the oil conducts the heat from piston skirts to cylinder walls where coolant carries it to radiator...
Oil galleries often run adjacent to coolant passages to help because the oil is hotter than the coolant.
engines are designed around this concept ...
Last edited:
I run oil coolers on my hot rods and trucks. Adds capacity and yes....the engines coolant temps run cooler with a oil cooler cruising down the road than without. Same radiator/same coolant capacity/same thermostat.
MolaKule
Staff member
Originally Posted By: camrydriver111
I was asking about the term "thermodynamic solution".
I see now what you are saying, and I thought everyone would remember the solutions to a set of simple thermo equations I had done in the past, a "Back of the Napkin" thingy. I mean, it was only 14 years ago.
From BITOG 7/2002:
Quote:
NOTE: This was for pure mineral oil verses pure PAO synthetic both 10.5 cST@100C.
H = F.rho.c(To-Ti),
where H is heat energy in Joules, F is volume flow in cubic meters/s,
c is heat capacity in Joules/kg.C, and temps in C. The c for synthetic oil is 2000 J/kg.C and c for dino is 1780 J/kg.C. I assumed a flow rate was 1/4 liter per second, To is temp out of a journal bearing = 100 C, and Ti was oil temp into bearing = 80C, representing a temp rise of 20C, which is a rule of thumb.
Hs = convective energy transfer in Joules for synthetic = 10.65 J
Hd = convective energy transfer in Joules for dino (mineral oil) = 9.3 J.
Therefore, pure synthetic oil is 13% more efficient at convective heat transfer.
The "rho" factor (oil convection heat transfer) is the oil's density, measured in kg/cubic meters, and since both oils were so close in density, I used 1.065 kg/cubic meter.
Using the Heat Conduction formula:
H = kA(To-Ti/L),
where H is heat Power in W.m, k is heat conduction coefficient in W/meter-squared/C, and temps in C. The k for synthetic oil is 0.16 and k for dino is 0.128, To is temp out of a journal bearing = 100 C, and Ti was oil temp into bearing = 80C, representing a temp rise of 20C, which is a rule of thumb. L is the thickness of the oil film which is on the order of 1um at high loads. A is area of film assumed to be a patch of area of 1 mm squared.
Hs = conductive heat transfer of synthetic oil in W = 3200 W,
Hd = conductive heat transfer of dino (mineral oil) in W = 2560 W.
Therefore, pure synthetic oil is 20% more efficient at conductive heat transfer than mineral oil.
The same film thickness for both dino's and synth's were used for the calculations.
The heat transfer formulas were from thermodynamics. The constants I used for "c" and "k" were from Michael J. Neal's, The Handbook of Tribiology.
Also see:
Tribology Congress III
September 12-16, 2005, Washington, D.C., USA
WTC2005-64316
HEAT TRANSFER PROPERTIES OF ENGINE OILS
Wrenick, Scott, Sutor, Paul1, Pangilinan, Harold, Schwarz, Ernest E.
1 Surfaces Research, Lenexa, KS
2 U.S. Army Tank-Automotive and Armaments Command, Warren, MI
and
Heat transfer characteristics of some oils
used for engine cooling
Hosny Z. Abou-Ziyan *
Mech. Power Eng. Dept., Faculty of Engineering, Mattaria, Helwan University, Cairo 11718, Egypt
Energy Conversion and Management 45 (2004) 2553–2569.
I was asking about the term "thermodynamic solution".
I see now what you are saying, and I thought everyone would remember the solutions to a set of simple thermo equations I had done in the past, a "Back of the Napkin" thingy. I mean, it was only 14 years ago.
From BITOG 7/2002:
Quote:
NOTE: This was for pure mineral oil verses pure PAO synthetic both 10.5 cST@100C.
H = F.rho.c(To-Ti),
where H is heat energy in Joules, F is volume flow in cubic meters/s,
c is heat capacity in Joules/kg.C, and temps in C. The c for synthetic oil is 2000 J/kg.C and c for dino is 1780 J/kg.C. I assumed a flow rate was 1/4 liter per second, To is temp out of a journal bearing = 100 C, and Ti was oil temp into bearing = 80C, representing a temp rise of 20C, which is a rule of thumb.
Hs = convective energy transfer in Joules for synthetic = 10.65 J
Hd = convective energy transfer in Joules for dino (mineral oil) = 9.3 J.
Therefore, pure synthetic oil is 13% more efficient at convective heat transfer.
The "rho" factor (oil convection heat transfer) is the oil's density, measured in kg/cubic meters, and since both oils were so close in density, I used 1.065 kg/cubic meter.
Using the Heat Conduction formula:
H = kA(To-Ti/L),
where H is heat Power in W.m, k is heat conduction coefficient in W/meter-squared/C, and temps in C. The k for synthetic oil is 0.16 and k for dino is 0.128, To is temp out of a journal bearing = 100 C, and Ti was oil temp into bearing = 80C, representing a temp rise of 20C, which is a rule of thumb. L is the thickness of the oil film which is on the order of 1um at high loads. A is area of film assumed to be a patch of area of 1 mm squared.
Hs = conductive heat transfer of synthetic oil in W = 3200 W,
Hd = conductive heat transfer of dino (mineral oil) in W = 2560 W.
Therefore, pure synthetic oil is 20% more efficient at conductive heat transfer than mineral oil.
The same film thickness for both dino's and synth's were used for the calculations.
The heat transfer formulas were from thermodynamics. The constants I used for "c" and "k" were from Michael J. Neal's, The Handbook of Tribiology.
Also see:
Tribology Congress III
September 12-16, 2005, Washington, D.C., USA
WTC2005-64316
HEAT TRANSFER PROPERTIES OF ENGINE OILS
Wrenick, Scott, Sutor, Paul1, Pangilinan, Harold, Schwarz, Ernest E.
1 Surfaces Research, Lenexa, KS
2 U.S. Army Tank-Automotive and Armaments Command, Warren, MI
and
Heat transfer characteristics of some oils
used for engine cooling
Hosny Z. Abou-Ziyan *
Mech. Power Eng. Dept., Faculty of Engineering, Mattaria, Helwan University, Cairo 11718, Egypt
Energy Conversion and Management 45 (2004) 2553–2569.
Last edited:
MolaKule
Staff member
Also see:
FLOW AND HEAT TRANSFER MODELLING
OF AN AUTOMOTIVE ENGINE
LUBRICATION SYSTEM
Volume I
Marcus B. M. Fenton
It was available Online at one time.
FLOW AND HEAT TRANSFER MODELLING
OF AN AUTOMOTIVE ENGINE
LUBRICATION SYSTEM
Volume I
Marcus B. M. Fenton
It was available Online at one time.
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