Charon
|
I am afraid I must disagree. The heat is generated in the combustion chamber, not in the "internal parts of the engine." The only heat generated in the "internal parts of the engine" is that caused by friction in the moving parts, and that is a pretty low percentage of the total.
The heat is generated in the combustion chamber by burning fuel and air. The engine converts about 25% of that heat to useable work and wastes the rest. About half of the waste heat leaves the engine in the form of hot exhaust gas. The other half of the waste heat leaves via the cooling system. The heat is directly imparted to the piston, cylinder head, and cylinder walls. The heat imparted to the head and cylinder is conducted through the metal to whatever is used as a coolant, either air or water. The heat imparted to the piston is usually conducted to the cylinder walls, somtimes via the rings. Some, but not all, four-stroke engines spray oil onto the bottom of the piston crown, and that oil is used to carry away excess heat. The side effect is that the oil scraper rings have more work to do getting the excess oil off the cylinder walls. Unless specifically designed to be oil-cooled (early Suzuki GSX-R), oil carries away only about 1 to 5% of the engine heat. The oil does cool engine bearings, as well as lubricating them.
Lest anyone believe I am "picking nits," I submit for consideration the lowly two-stroke engine, widely used in such things as outboards, chain saws, and so on. Those engines do not have engine oil, except for the quite small amount that passes through them with the fuel. Therefore, they cannot depend on oil as a coolant.
I will pass on the comment about synthetic versus mineral oils, as neither is very good as a coolant. The synthetic oils are reputed to withstand high temperatures better, but that doesn't make them better as coolants.
|