Quote:
Originally Posted by mwebb
i do not understand your question , then again
you do not have a question
your statement is false do not proceed with your experiment .
the answer is
AVERAGE
peak combustion pressure must happen at about 14 degrees after top dead center
not so important at idle as at every other condition of engine operation
spark duration is almost always longer than 1ms but the combustion event itself takes much more time than the time for the spark event
the spark event will end before the combustion event
the timing advance / change for the spark event
changes
with rpm and load and temperature
and
the spark event is timed so that the combustion event produces peak pressure at 14 degree after TDC
=================
if
peak combustion pressure does not happen at 14 degrees after TDC because someone tampers with base ignition timing
peak power and peak efficiency are reduced / decreased
emissions increase
and
if base ignition timing is advanced enough so that some random combustion events get to peak combustion pressure before TDC
the engine will be damaged .
do not frack with it
|
Well I did Frack with
Twice now the first one died a bad death, spark plugs would only last 3-4 days before they carbon-ed up and stopped working while with heavy knocking.
Here is a video I made in 2002 sept
I thought the fuel had ruined my engine but
I patched up the bottom end an lowered the compression to 8:1 and discovered some strange engine timings.
On this page
New Page 1 the bottom graph has a red trace, these values came from my timing computer just before the patched bottom end died again.
Yes I understand about Peak Combustion Pressure (PCP).