HD engine, economy and wear 5W30 vs 0W20

[MolaKule]

Originally Posted By: turtlevette
Originally Posted By: MolaKule
Originally Posted By: turtlevette




The other thing to remind shannow, is that the volume of oil actually going through the hydrodynamic space is very small. Most of the oil circulation is excess. The bearings contribute a small volume of hot oil.



An real engineer would know that "hydrodynamic" is a descriptive condition, not a physical space.

The oil "wedge" would be the physical "space."


You're going to argue terms but not my statement about the volume?

Good enough for me. I'm an EE not mechanical.



What was your oil volume statement? You vacillate with so many different topics it is difficult to follow you.

And yes, words and phrases have meanings.


Regarding Bearing Temp, Oil Volume and Oil Flow:

The oil flow and temperature in a bearing rig (bearing isolated) with a specified load and constant oil inlet temperature of 120C was as follows,

At an oil volume exchange rate of 5 cm^3/s @ an Oil Velocity of 10.9 m/s, the bearing temp averaged 150C.

At an oil volume exchange rate of 10 cm^3/s @ an Oil Velocity of 10.9 m/s, the bearing temp averaged 140C.

At an oil volume exchange rate of 15 cm^3/s @ an Oil Velocity of 10.9 m/s, the bearing temp averaged 135C.

AT an oil volume exchange rate of > = 17 cm^/2, the bearing temp curves flatted out.


SAE Paper 910160

 

[HerrStig]

Originally Posted By: MolaKule
Originally Posted By: turtlevette
Originally Posted By: MolaKule
Originally Posted By: turtlevette




The other thing to remind shannow, is that the volume of oil actually going through the hydrodynamic space is very small. Most of the oil circulation is excess. The bearings contribute a small volume of hot oil.



An real engineer would know that "hydrodynamic" is a descriptive condition, not a physical space.

The oil "wedge" would be the physical "space."


You're going to argue terms but not my statement about the volume?

Good enough for me. I'm an EE not mechanical.



What was your oil volume statement? You vacillate with so many different topics it is difficult to follow you.

And yes, words and phrases have meanings.


Regarding Bearing Temp, Oil Volume and Oil Flow:

The oil flow and temperature in a bearing rig (bearing isolated) with a specified load and constant oil inlet temperature of 120C was as follows,

At an oil volume exchange rate of 5 cm^3/s @ an Oil Velocity of 10.9 m/s, the bearing temp averaged 150C.

At an oil volume exchange rate of 10 cm^3/s @ an Oil Velocity of 10.9 m/s, the bearing temp averaged 140C.

At an oil volume exchange rate of 15 cm^3/s @ an Oil Velocity of 10.9 m/s, the bearing temp averaged 135C.

AT an oil volume exchange rate of > = 17 cm^/2, the bearing temp curves flatted out.


SAE Paper 910160

 

[HerrStig]

Have we disabused ourselves of the notion that "all big motors are grease lubricated" yet? Perhaps that comment has become "inconvenient".

 

[MolaKule]

Topics change quickly when scientific facts dispute widely held notions.

 

[Festiva_Man]

Originally Posted By: Shannow
Originally Posted By: Festiva_Man
that would tell me that it has more to do with the oil pan seeing more air cooling while the engine warms up than the coolant does with the thermostat controlling it.
maybe what we need is a second 'coolant pan' around the outside of the oil pan that makes coolant flow all the way around the outside of the oil pan maybe an inch and a half thick. insulate the coolant pan very well so air doesnt cool it off too much. then the coolant would heat the oil up faster to 200f and get our oil to the proper viscosity quicker and then it would cool it once the oil tried to get hotter than 200f. probably a thermostatically controlled oil cooler would still be needed for track cars or heavy duty trucks to prevent coolant overheating.
are there flaws in this idea or why isnt this done?



Some interesting stuff in this paper.

http://eprints.nottingham.ac.uk/13180/1/Thesis_JP.pdf

with regard to improving bulk oil warmup time.



well i finally finished reading that thesis statement by that guy going for a philosophy degree and i learned quite a bit, thanks for that! i understand much better now how heat flows through an engine and why it takes so much longer for the oil to heat up. i did not realize that most of the piston heat went to the coolant without piston cooling jets, i thought it mostly went to the oil. i almost want to go put an oil to coolant heat exchanger on my car now! except i think that would be a disadvantage after the oil and coolant temps meet as my coolant runs at 170f and the oil at 212f. it would probably cool my oil too much. so i see that my idea of running the coolant around the oil pan would not help as much as i thought. there are better ways like the Filter Cooler Assembly in that study to bring the 2 temps closer togeather, but i still think insulating the pan would help very significantly. in the europian drive cycle and all the testing in this thesis statement an urban drive is done at low speeds first untill the car is warm before hitting the highway and its all done at 26c ambient. so airflow cooling the pan or engine during warmup is almost neglagable and when it finally does happen its hot air. i think the majority of driving they are concerned with is commuting and this isnt accurite. people drive to work in the morning when its much cooler than 26c and home when its about 26 only half the year; the other half is much colder. also a lot of people live out of town and drive in to town for work, or drive to a different town for work... anyway, they didnt consider insulating or blocking airflow much in this study because they only considered hot temperatures and slow drives during warm up so that wouldn't help. running coolant around the pan during warmup in cold weather would cool the coolant off too much as well as adding extra coolant that needs to be heated all extending the warmup time. but i think insulating the pan would help considerably as thats what sees a lot of airflow in the cold. the active shutters new cars have probably help a lot as well, same as toyotas 1.2L turbo that has a water 'cooled' exhaust manifold. it was interesting to see all the ways that heat is transferred more to the oil on their test car than it is on mine: they had a turbo, egr cooler, piston cooling jets, hotter thermostat and a filter cooler. all that adds up to the oil heating up way sooner than on my car. i am considering insulating my oil pan half way through the winter and seeing what that does. i am recording warmup times and oil temps in a different experiment already. but i have a blown civic motor that i am tearing apart right now to try and understand how it works better and to see better all these strange designs honda has.
anyway, thanks again for that thesis paper! and do you think there is a better way to help the oil warm up faster in the winter on my car than insulating the pan? do you agree or disagree that a coolant to oil heat exchanger wouldnt help because my coolant runs too cold?
and to the guy who thinks friction doesnt heat up oil: take for example a gearbox, even a rear diff or manual transmission- they get really really hot if they have a decent amount of power going through them and are not cooled. why? because friction causes heat. in a bearing the friction is not between the 2 metal surfaces but in the oil itself, thats why it gets hot. without piston cooling jets not a lot of the piston heat even goes to the oil. read the thesis in what i am quoting.

 

[Shannow]

Festiva_Man,
IMO, coolant to oil heat exchangers are a must if there's a desire for that function to warm/thin the oil, and control the maximum oil temperatures.

I've had a few, a 3VZE in a 4Runner, and currently in my ZD30 turbodiesel. The former was a fake filter housing towards the back of the block, that was pretty dinky.

The latter, as I've only found out the last few days means that Nissan Renault really had a plan with the system.

The cooler is bathed in coolant...the thermostat is on the inlet side of the water pump (my preferred location).

It's pretty cold at the moment, and I'm driving the Nissan to work most days. About 2-3 miles of highway running cold, and the water is showing normal on the needle (it's a dumb guage I think), at 5 miles, the heater suddenly starts pumping and needs to be turned down.

At idle, it will never blow heat, and has a "heat" button that raises idle to 1500RPM.

 

[Festiva_Man]

Originally Posted By: Shannow
Festiva_Man,
IMO, coolant to oil heat exchangers are a must if there's a desire for that function to warm/thin the oil, and control the maximum oil temperatures.

I've had a few, a 3VZE in a 4Runner, and currently in my ZD30 turbodiesel. The former was a fake filter housing towards the back of the block, that was pretty dinky.

The latter, as I've only found out the last few days means that Nissan Renault really had a plan with the system.

The cooler is bathed in coolant...the thermostat is on the inlet side of the water pump (my preferred location).

It's pretty cold at the moment, and I'm driving the Nissan to work most days. About 2-3 miles of highway running cold, and the water is showing normal on the needle (it's a dumb guage I think), at 5 miles, the heater suddenly starts pumping and needs to be turned down.

At idle, it will never blow heat, and has a "heat" button that raises idle to 1500RPM.


wow, thats quite the elaborate setup there!
i see the oil to coolant heat exchangers as very useful, i just dont know how well it would work if i tried to do my own setup on my car. if oil temps are normally 212-220f wouldn't cooling it down to 180f be bad for your fuel economy not better? i dont see the point of the 170f coolant thermostat my car has, but im not brave enough to put a 195f in and then find out there was a reason...

 

[Jetronic]

the measured oil temp is usually where the oil temp is at it's lowest. From there the temp goes up again in various amounts depending where the oil actually is going, and then cools down as it sinks to the sump (and while it's there waiting to get pumped again).

It'll be great to limit oxidation of the oil to keep the bulk at 180-ish for normal cruising, and even better to get it there more quickly.

There's a a real potential for longer oci if the oil temperature is controlled.

 

[camrydriver111]

For car manufacturers that spec 0W20 do you think the engines are designed to handle the low HTHS without metal to metal contact?

 

[Shannow]

Originally Posted By: camrydriver111
For car manufacturers that spec 0W20 do you think the engines are designed to handle the low HTHS without metal to metal contact?


Nope, they freely admit in their movement into GF-6 that the new test engines have to exhibit boundary/mixed lubrication "just like' the newer generation engines are.

They are designing them with mixed lubrication these days.