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a question
- Thread starter yannis
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There really is no good answer, but the areas exposed to direct combustion are cooled only by a boundary layer of unburned fuel that is a few molecules thick. Otherwise they would be exposed to temperatures above 1000 degrees F. Combustion heat does get transferred by the exhaust valve to the oil lubricating the exhaust valve guide, and this is a hot spot. I don't have anything close to good actual estimated temperatures, however.
Google might turn up some actual numbers for you. Interested to see what others might have to say, too.
Google might turn up some actual numbers for you. Interested to see what others might have to say, too.
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I would imagine the underside of the piston under normal conditions. This is probably the backside cause of oil coking in the ring packs in many engines. The cylinders are water jacket cooled as is much of the head.
In a gasoline engine at full load the temperature of the piston top land is generally higher than that of the piston rings. This temperature is approximately 250C or 482F. The further down the piston the lower the temperature where at the bottom circumference of the skirt is approximately 125C or 257F.
In a direct injection diesel engine the temp. is approx. 300C at top and 130C at bottom.
Source: Piston Ring Tribology by Peter Andersson
It may still be online for download.
In a direct injection diesel engine the temp. is approx. 300C at top and 130C at bottom.
Source: Piston Ring Tribology by Peter Andersson
It may still be online for download.
Here you go! http://www.vtt.fi/inf/pdf/tiedotteet/2002/T2178.pdf
Very interesting read JAG.
The following paragraph correlates with my 1400 F faint memory although such temperatures occur when there is a problem in lubrication.
"On the piston ring and cylinder liner surfaces evidence of scuffing may be found in the shape of wear scars indicating, e.g., plastic deformation, abrasive ploughing and the adhesive transfer of work hardened cast iron to a chromium-plated piston ring, and a "white layer" that indicates that the temperature has locally exceeded 750°C (Lacey and Stockwell, 1999).
The scuffing phenomenon is normally preceded by conditions of locally starved lubrication, and the occurrence of flash temperatures, or "hot spots", in the ring/liner contact. The local temperature increase can, in turn, cause the formation of local thermal expansion of the cylinder wall material towards the bore ("thermal bump"), which instantly leads to an increase in the contact pressure in the ring/liner contact.
"
and an other one:
"In addition to sliding wear, surface degradation of piston rings can take place due to blow-by of hot gases from the combustion chamber, where the temperature of the combustion gas is in the excess of 2 000°C.
The blow-by can cause local melting or hot gas erosion damages, or burn scars, on the rings. In engines where ring deterioration
owing to blow-by is likely to occur, the use of molybdenum or similar heat-resistant coatings is essential (Brauers and Neuhäuser, 1989)."
The following paragraph correlates with my 1400 F faint memory although such temperatures occur when there is a problem in lubrication.
"On the piston ring and cylinder liner surfaces evidence of scuffing may be found in the shape of wear scars indicating, e.g., plastic deformation, abrasive ploughing and the adhesive transfer of work hardened cast iron to a chromium-plated piston ring, and a "white layer" that indicates that the temperature has locally exceeded 750°C (Lacey and Stockwell, 1999).
The scuffing phenomenon is normally preceded by conditions of locally starved lubrication, and the occurrence of flash temperatures, or "hot spots", in the ring/liner contact. The local temperature increase can, in turn, cause the formation of local thermal expansion of the cylinder wall material towards the bore ("thermal bump"), which instantly leads to an increase in the contact pressure in the ring/liner contact.
"
and an other one:
"In addition to sliding wear, surface degradation of piston rings can take place due to blow-by of hot gases from the combustion chamber, where the temperature of the combustion gas is in the excess of 2 000°C.
The blow-by can cause local melting or hot gas erosion damages, or burn scars, on the rings. In engines where ring deterioration
owing to blow-by is likely to occur, the use of molybdenum or similar heat-resistant coatings is essential (Brauers and Neuhäuser, 1989)."
I'm glad you liked the paper.
Off-topic: I've never been to Greece but want to badly and love reading the history of Greece. Greece is the cream of the crop in world history.
Off-topic: I've never been to Greece but want to badly and love reading the history of Greece. Greece is the cream of the crop in world history.
Yes, I've been warned of similar things by a native of Greece who lives here. She said only go to one of the islands...avoid main-land Greece. Darn it...I want to see the Parthenon!
Back on topic, why did you ask the question in your first post in this thread? It's a good question. It is said that the ring belt area of an engine is "Ground Zero" for the attack on motor oil. The chemical reactions there are the largest driver of oil degradation.
Back on topic, why did you ask the question in your first post in this thread? It's a good question. It is said that the ring belt area of an engine is "Ground Zero" for the attack on motor oil. The chemical reactions there are the largest driver of oil degradation.
We had a 450 year slavery under the Ottoman Empire( 1453-1921) which left its mark to everything.
People like you who were facinated with the past achievemnts ,from France, England, Russia gave their lives and helped us in the revolution .
And stil keep helping (here) lol .
I asked the original question looking for a verification to a post i made yesterday in a greek forum regarding max. oil temperatures. I wasn't 100% sure .
By the way BITOG and amsoil are quite popular here.
People like you who were facinated with the past achievemnts ,from France, England, Russia gave their lives and helped us in the revolution .
And stil keep helping (here) lol .
I asked the original question looking for a verification to a post i made yesterday in a greek forum regarding max. oil temperatures. I wasn't 100% sure .
By the way BITOG and amsoil are quite popular here.
Aha, I see. I'm sorry to hear about the Ottoman slavery. That part of Greek history is less talked about in books.
That's cool that BITOG and Amsoil are popular there!
That's cool that BITOG and Amsoil are popular there!
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