Oil cooler and high volume pump gears

[scotty]

if you slow the flow through the cooler then the air will have more time to cool that amount of oil((ABSORB THE HEAT))- In air conditioning we slow the air flow down to allow it to have more heat removed from it into the freon in the closed system. seems the same. we have to transfer heat .

[Mr. Jiggles]

But using this line of reasoning wouldn't you expect that the slower you're moving through the air the better your engine and oil cooler would be??

Not really. What he is saying is theoretically correct. The ratio of the amount of time the oil is in the cooler to the time the oil is in the engine is the same (we call that the duty cycle in electronics) the frequency has changed is all. Mathematically speaking - the average temperature will no change.

Now, if the dynamics of the cooler change (size, efficiency, air flow, etc.) then the temperature of the oil will change.

How is air different from oil?

I agree that if the cooler is at it's limit with regard to exchanging heat into the air (for instance being stuck in traffic) then passing more oil through it will not improve its efficiency but what I'm reading is that efficiency will drop the faster the oil moves through the cooler. If this was the case then we wouldn't have to worry about wind chill.

[Jethro]

Hey Jethro, you're hurting my feelings mate, I wouldn't make a substandard adapter that didn't incorporate your standard oil pressure switch! Hell, I even offer an optional oil temp sensor in mine, unlike the "professionals", much more expensive adapters, ha ha!

Ok, I'll bite- why should I use your adapter instead of plumbing into the taps on either side of the oil filter cover? I've already bought an 1150 cover as suggested to prohibit the flow through the filter housing somewhat- does your system require the same cover or do I use my stock cover? How do your route the lines for your adapter? I have the stock 1150 lines in great shape, but maybe your system is better because it taps right to the oil output? If so, I might be convinced to go for it.

Sorry if I hurt your feelings mate, I just remember seeing something about your adapter that made you lose your pressure light. But that was probably a couple years ago.

Your adapter looks real nice! Now sell me on it!

[Anonymous]

But using this line of reasoning wouldn't you expect that the slower you're moving through the air the better your engine and oil cooler would be??

Not really. What he is saying is theoretically correct. The ratio of the amount of time the oil is in the cooler to the time the oil is in the engine is the same (we call that the duty cycle in electronics) the frequency has changed is all. Mathematically speaking - the average temperature will no change.

Now, if the dynamics of the cooler change (size, efficiency, air flow, etc.) then the temperature of the oil will change.

How is air different from oil?

I agree that if the cooler is at it's limit with regard to exchanging heat into the air (for instance being stuck in traffic) then passing more oil through it will not improve its efficiency but what I'm reading is that efficiency will drop the faster the oil moves through the cooler. If this was the case then we wouldn't have to worry about wind chill.

First, wind chill has no effect. This is a term used to describe a temperature effect generated by moving air. It is not valid for mechanical systems, only living organisms.

If you slow the oil throught the cooler, yes, it cools the oil more. However, the oil in the engine isn't being cycled through the cooler as fast, so it heats up more. The end result is that the overall temperature remains the same. I'm just using math - duty cycle and period analysis. The duty cycle remains the same (ratio of the oil in the cooler to the oil in the engine), only the frequency is changing (overall period of the exhange). This keeps the average value constant.

Now, there is one other factor to consider. Maximum temperature exchange takes place at higher differential temperatures (oil temp to ambient air temp). So, the efficiency increases slightly when the engine is hottest. Since you do not want the maximum temperature in the engine, this is one part of the equation you would want to avoid.

I would think an air conditioner is slightly different. The heat that you are trying to remove from the house has a much larger time constant than that generated by the engine. There is a difference in the dynamics of the system - just enough so that they are not entirely the same.

Of course, I could be wrong, it's happened before.

[Mr. Jiggles]

But using this line of reasoning wouldn't you expect that the slower you're moving through the air the better your engine and oil cooler would be??

Not really. What he is saying is theoretically correct. The ratio of the amount of time the oil is in the cooler to the time the oil is in the engine is the same (we call that the duty cycle in electronics) the frequency has changed is all. Mathematically speaking - the average temperature will no change.

Now, if the dynamics of the cooler change (size, efficiency, air flow, etc.) then the temperature of the oil will change.

How is air different from oil?

I agree that if the cooler is at it's limit with regard to exchanging heat into the air (for instance being stuck in traffic) then passing more oil through it will not improve its efficiency but what I'm reading is that efficiency will drop the faster the oil moves through the cooler. If this was the case then we wouldn't have to worry about wind chill.

First, wind chill has no effect. This is a term used to describe a temperature effect generated by moving air. It is not valid for mechanical systems, only living organisms.

If you slow the oil throught the cooler, yes, it cools the oil more. However, the oil in the engine isn't being cycled through the cooler as fast, so it heats up more. The end result is that the overall temperature remains the same. I'm just using math - duty cycle and period analysis. The duty cycle remains the same (ratio of the oil in the cooler to the oil in the engine), only the frequency is changing (overall period of the exhange). This keeps the average value constant.

Now, there is one other factor to consider. Maximum temperature exchange takes place at higher differential temperatures (oil temp to ambient air temp). So, the efficiency increases slightly when the engine is hottest. Since you do not want the maximum temperature in the engine, this is one part of the equation you would want to avoid.

I would think an air conditioner is slightly different. The heat that you are trying to remove from the house has a much larger time constant than that generated by the engine. There is a difference in the dynamics of the system - just enough so that they are not entirely the same.

To be perfectly honest I'm not convinced that I'm right here but I know from a lot of experience that things that might appear to be intuitive are often incorrect. It looks like we're looking at the issue in two different ways - you're seeing the cooling effect as a function of time the oil spends in the engine and cooler while I'm looking at it in terms of calories of heat per unit volume - higher volume passed leads to more calories passed. I'm making the assumption that increasing the flow rate in this scenario does not lead to a reduction in the efficiency of heat transfer between either the oil and engine block. The reason I'm making this assumption is that I'm thinking about the mass of the aluminum and steel in the engine and the number of calories of heat that represents, and the ratio of the surface area of the oil passages, crank/camshafts, gears, cylinder head, etc to the volume of oil - it's enormous. For this reason and the fact that the oil system is closed I would consider the hot oil to be in endless supply as long as the engine is running, regardless of its flow rate. As far as the cooler is concerned, I have to disagree with the notion that the faster a fluid is moving across a stationary object the less it's cooling effect will be. This might be true in a situation where you have a finite volume of fluid moving across the object (faster flow rate = less contact time) and you're rate of cooling is proportional to the time spent in contact with the object; but that isn't the case here - the oil supply is unlimited. Since the oil passages in the cooler also have a high surface area to volume ratio this would make the effect of the rate of oil passed through the cooler the same as the rate of air passed across the cooler's fins IMO. That is, barring any turbulence / cavitation effect higher flow rates result in more heat transfered as long as heat transfer from the fins to the air hasn't been maxed out.

You're right about the wind chill term applying to humans but the effect is rooted in thermodynamic principles. The chilling effect that we feel on a cold windy day (no sweating involved) is no different that the effect that moving air has on our engines In my lab we have circulating and non-circulating water baths. If I have something that I want to warm or cool in a hurry I always pick the circulating bath since it will warm or cool about 10x faster than the non-circulating type, even though the water is moving faster over the surface of the object.

Any engineers or physicists care to weigh in on this??

[Jethro]

Well lookie here. Another one of my posts that has gone so far above my head that I can no longer participate in it! Oh well...

[terry]

[quote="JethroOk, I'll bite- why should I use your adapter instead of plumbing into the taps on either side of the oil filter cover? I've already bought an 1150 cover as suggested to prohibit the flow through the filter housing somewhat- does your system require the same cover or do I use my stock cover? How do your route the lines for your adapter? I have the stock 1150 lines in great shape, but maybe your system is better because it taps right to the oil output? If so, I might be convinced to go for it.

Sorry if I hurt your feelings mate, I just remember seeing something about your adapter that made you lose your pressure light. But that was probably a couple years ago.

Your adapter looks real nice! Now sell me on it![/quote]

G'Day Jethro, no mate, I'm a soldier, not a salesman, so if you reckon your method will work as well or better than mine, "fill your boots". I'm glad you thought mine looks nice though. Cheers, Terry. :twisted: