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Author Topic: Lambda for catalyst protection is LASOAB  (Read 3893 times)
ta79pr
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« on: March 10, 2012, 04:48:16 AM »

I noticed this in Banish's book:
"For this reason, many OEM vehicles sold today approach L = 0.82 (12.0:1 air/fuel) or richer once catalyst protection threshold has been reached. Unlocking control of this protection can be the key to properly calibrating such vehicles." Greg Banish, Engine Management, Advanced Tuning, p. 53.

I see "component protection" mentioned a lot, is that what we are talking about? I thought that was more like turbos and valves.

And if we did disable this protection (which is probably there to make the CC last throughout the emissions warranty) what happens, does the CC just burn through, or does it get clogged - what does enrichment protection seek to do?

I am guessing this is KSWF and KFKSWF. Pages 732 of the english Alfa FR states:
"The priorities of lambdaselection are catalyst protection, component protection, catalyst heating by secondary air.
Lambda for catalyst protection is LASOAB.
Component protection for manifold, exhaust valves, supercharger, catalyzer is realized by means of the two inputs lambts w and
dlambts w.
"

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02 TT tdi (BEW)
2005 allroad 2.7tM (BEL)
silentbob
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« Reply #1 on: March 10, 2012, 11:59:05 AM »

I noticed this in Banish's book:
"For this reason, many OEM vehicles sold today approach L = 0.82 (12.0:1 air/fuel) or richer once catalyst protection threshold has been reached. Unlocking control of this protection can be the key to properly calibrating such vehicles." Greg Banish, Engine Management, Advanced Tuning, p. 53.

I see "component protection" mentioned a lot, is that what we are talking about? I thought that was more like turbos and valves.

And if we did disable this protection (which is probably there to make the CC last throughout the emissions warranty) what happens, does the CC just burn through, or does it get clogged - what does enrichment protection seek to do?

I am guessing this is KSWF and KFKSWF. Pages 732 of the english Alfa FR states:
"The priorities of lambdaselection are catalyst protection, component protection, catalyst heating by secondary air.
Lambda for catalyst protection is LASOAB.
Component protection for manifold, exhaust valves, supercharger, catalyzer is realized by means of the two inputs lambts w and
dlambts w.
"



This is highly dependant of what kind of engine you have.
On turbocharged engines usually the turbo is the limiting factor that has to be protected. The catalyst sees not as much temp as the turbine takes away a lot of heat ~150°C on full load high rpms.
On cheap engines usually the exhaust valves are the limiting factor.
On supercharged and "normal" NA engines it's usually the catalyst. Depending on the coating static temperatur is limited to ~950°C. This is a pretty high temperature as in dynamic situations the catalyst can see much higher.
I don't know if this quote is ripped out of a context, but I can't imagine that he has given that as a general advice.
« Last Edit: March 10, 2012, 02:19:02 PM by silentbob » Logged
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