"Absorb" is really not the correct word here. I'd use the word heat transfer and not engine, but rather individual engine parts.
Also, I strongly disagree about EGT not being important. Exceed a certain EGT and you will melt the head/piston, every time.
Yeah sorry for my english, heat transfer soundes better
But EGT probe in the exhaust measure temperature... in the exhaust
Not in the cylinder
As i said you can have more heat inside cylinder and less outside and other way around
You can hold the engine in steady state with the same charge and mix, and simply retard the ignition until catastrophic failure occurs.
According to your logic this is impossible.
I was taught other way around
Retarding ignition cools cylinder.
Combustion heat balance looks more or less like this:
1. 30% - is lost with exhaust
2. 30% - is lost into cylinder (heats up engine parts)
3. 30% - is what actually heats up air producing pressure
Heat 1. is exhaust stress.
Heat 2. is engine internals stress (pistons, cylinders, valves)
The more you retard ignition the more heat goes into 1. and less into 2.
So you simply cools cylinder
But at the same time you heat up exhaust parts
For example - launching ALS - you see massive EGT rise but you also cool down cylinders - but you do not see this because you do not have temp. sensor inside cylinder.
Fun fact - we had test engine in the lab with temperature and pressure sensors installed and they were very accurate and even more expensive
No one cared about EGT temperature in the lab
What was important was temperature inside cylinder (and pressure).
But because we do not have NASA like equipment available for our cars so we put primitive cheap EGT probes inside exhaust that do not tell us much about what is going inside engine but that is all we have
It's like watching distant galaxies with telescope - we can't go there personally and measure anything directly so we just observe it from far away and make assumptions what is going on there
The more kinetic energy is extracted out of the charge, the less waste thermal energy is left over, very simple.
And again "kinetic" energy is related to speed when body with certain mass is moving.
There is no kinetic energy extraction from combustion
Burning mixture has no kinetic energy and does not do any work. It just heats up medium (itself).
As i said there are engines that have external heat source like Stirling engine.
Stirling engine has no intake or exhaust, medium is closed inside.
You heat it up externally by heating cylinder walls!
And it works like ICE engine - all that matters is pressure - how you get pressure is irrelevant.
And as for thermal waste i wrote about it above.
If your exhaust is very hot, then you're constantly heating the area near the exhaust valves until it melts.
On other hand, if you have e.g. preignition/glow ignition, then you will melt the piston near the spark plug without hearing a peep.
Preignition or detonation is another topic.
Mixture ignited normally (with spark plug) burns quite slow at constant rate - so that why you advance ignition with engine speed.
But when too much heat or pressure it can self detonate and it causes more heat and more pressure and more self ignition occurs.
Then pressure inside cylinder goes crazy (jumps violently all the way around) and combustion is disrupted.
For example if you put too "hot" plugs they do not transfer enough heat off the plug itself to the head so they get too hot and start working like glow plugs in diesels pre-igniting mixture.
btw. this discussion made me refresh some knowledge from studies that i started to forgot:)
