Engine temperatures

[widdowson2008]

From data collected, the mean temperatures after the system has gone through the warming up phase and sort of stabilised are as follows:

Head - 89 degrees C
Block - 65 degrees C

These are coolant temperatures.

Are these what you can reasonably expect?

Tests are ongoing, but the data so far seems to be settling down to the above figures.

[dandywarhol]

Sounds fine to me - a 1 bar pressure cap blow off will allow the temp to get to around 120 C before letting off steam - that allows 30 deg to play with up hills and down dales

[widdowson2008]

Thanks Dandy.
Next question -
As I understand it (and I may be wrong) there are two totally different environments in a diesel engine, each requiring its own ideal operating temperature.
1 - The head, which requires an op temp high enough to detonate the fuel
2 - The block, which requires an op temp within the lubricating oil parameters

Would I be correct in assuming that the cooling system has been designed to maintain the temperatures currently being experienced in the data (89 head, 65 block) for the above reasons? or are there more?

I need to take this slow cos I need to understand it

[dandywarhol]

I would't think its anything more than natural upwards convection of coolant and the fact that the power explosion is in the piston bowl causing the temp differences. The mass of metal around these components will dictate the designed temperatures

[widdowson2008]

Grrrrrrrrrrrrrr. I think I need to rephrase the question (or take a step backward.)
upwards convection of coolant? Thought it was pumped throughout?
mass of metal around these components will dictate the designed temperatures? Wouldn't the ideal temperature of the flashpoint/detonation point be the design criteria for the head?
Not argueing at all - just asking questions.

What I am trying to nail down is
1 - What generates the heat (combustion + friction?)
2 - How much cooling goes on in each section of the system (between components.)

[dandywarhol]

Grrrrrrrrrrrrrr. I think I need to rephrase the question (or take a step backward.)
upwards convection of coolant? Thought it was pumped throughout?
mass of metal around these components will dictate the designed temperatures? Wouldn't the ideal temperature of the flashpoint/detonation point be the design criteria for the head?
Not argueing at all - just asking questions.

What I am trying to nail down is
1 - What generates the heat (combustion + friction?)
2 - How much cooling goes on in each section of the system (between components.)

Pump ASSISTED - heat conducts through the cylinder walls as a result of combustion and friction (as you said ), convects to the outlet from the head and radiates out to atmosphere from the various coolant pipes/tanks/martices/radiator. The pump just helps circulation

The cylinder temp is produced by the compressed air - needs to be at least 500 deg.C to spontaneously burn when the diesel is injected into the pre-combustion camber, so I guess a combination of water jacket design/head design/cooling system ancilliaries design will also contribute to the ideal controlled temperature

[widdowson2008]

Thanks for the lesson Dandy
Knew things got hot but 500deg.C Bloody hell

[dandywarhol]

Thats just to start the burn - around 2000 deg.C when combustion takes place for that split second - now y'know why the cooling system needs to be right

[widdowson2008]

Thats just to start the burn - around 2000 deg.C when combustion takes place for that split second - now y'know why the cooling system needs to be right

FRIGHTENING!!
So at 1500 RPM, that's 25 combustions of 2000 deg.C EVERY SECOND. WARALOT

[widdowson2008]

Thats just to start the burn - around 2000 deg.C when combustion takes place for that split second - now y'know why the cooling system needs to be right

FRIGHTENING!!
So at 1500 RPM, that's 25 combustions of 2000 deg.C EVERY SECOND. WARALOT

or is that 50 combustions? Whichever, its a lot banging going on.

[dandywarhol]

50

Now imagine an F1 engine at 1266 bangs/sec.