Anti-Ford guy bought a Fiesta
04-04-2011, 10:39 AM
#41
2 Props,3 Dildos,& 1 Cat
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ok I joe perezed this for academic purposes.
my car restarted when hot:
idling normally I idle at say 1000 rpm.
injection is about 1.87ms and 1.6% duty cycle.
that's 1.6% of the time, the injectors are squirting.
so for 10 seconds, i'm squirting 160ms worth of fuel.
a recent log's restart shows:
about 300ms of 6ms PW (1.4% duty, 225-480rpm)
about 150ms of 10ms PW (6.4% duty, 600-750rpm)
about 1000ms of 3ms PW (1.5% duty, 600-900rpm)
multiply the starting duties by the duration and you get
4.2ms of squirt
9.6ms of squirt
15.0ms of squirt
-----
28.8 ms of squirt to restart.
so I was wrong.
it's less than 2 seconds of idling. 28.8ms/1.6%=1800ms
(my car takes about half a second to fire and another second for after start enrichments)
keep in mind also the engine speed is lower during startup so you inject fuel less often.
if my maths are off, someone correct them.
my car restarted when hot:
idling normally I idle at say 1000 rpm.
injection is about 1.87ms and 1.6% duty cycle.
that's 1.6% of the time, the injectors are squirting.
so for 10 seconds, i'm squirting 160ms worth of fuel.
a recent log's restart shows:
about 300ms of 6ms PW (1.4% duty, 225-480rpm)
about 150ms of 10ms PW (6.4% duty, 600-750rpm)
about 1000ms of 3ms PW (1.5% duty, 600-900rpm)
multiply the starting duties by the duration and you get
4.2ms of squirt
9.6ms of squirt
15.0ms of squirt
-----
28.8 ms of squirt to restart.
so I was wrong.
it's less than 2 seconds of idling. 28.8ms/1.6%=1800ms
(my car takes about half a second to fire and another second for after start enrichments)
keep in mind also the engine speed is lower during startup so you inject fuel less often.
if my maths are off, someone correct them.
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04-04-2011, 10:57 AM
#42
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10 seconds was the same figure that i had seen. thanks for doing the math that i was too lazy to do.
obviously premature starter wear is a consideration. but since i will only do this extra start 2-3 times/day....i'm not worried.
obviously premature starter wear is a consideration. but since i will only do this extra start 2-3 times/day....i'm not worried.
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04-04-2011, 01:24 PM
#44
reading comprehension fail. i said "long" idle situations. here in NJ we have these lovely things called "jughandles" where you can sit parked for several minutes. are you suggesting that it takes several minutes of fuel to start an engine that is already at operating temperature? 
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