Ideal Balance for AFM?
#51
I'm a boost creep...
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Originally Posted by WAYNE88N/A
"Many times a second" doesn't answer my earlier question, though. Can we assume that the rate of change displayed on the meter (or the pretty little LED's) during stoich is also the rate of change made to fuel flow during all other transient events? If so, then we're looking at about 4 or 5 times a second...
Last edited by NZConvertible; 08-04-04 at 01:17 AM.
#52
Lives on the Forum
Hmmm, 100 hertz signal rate sounds kinda fishy...Let's assume a 3K cruise rpm; now, the CAS turns at half crank speed, correct? So 1500 rpm (25/sec) CAS input signals, all other fuel delivery related sensors (AFM, TPS, boost sensor, thermisters, etc..) are a straight DC voltage, no reference frequencies can be obtained from them, they have to be algorithmically mapped by the ECU before the results & fuel delivery outputs can be oscillated (or, switched to ground, if you prefer)...Now, at 3K, my primaries are doing something around a 22% duty cycle, which means no signal can be "delivered" (or changed) approx. 80% of the time. If we were to assume that the CAS signals "run the show", and that the injector pulsewidth can only actually be changed (compared to the previous pulse) when the coil is energized, we're looking at 25/.22, or 5.5 times per second (double this for 6K rpm, of course). Which, by the way, is almost exactly what the O2 sensor is showing me at 3K...
#53
Originally Posted by WAYNE88N/A
Hmmm, 100 hertz signal rate sounds kinda fishy...Let's assume a 3K cruise rpm; now, the CAS turns at half crank speed, correct? So 1500 rpm (25/sec) CAS input signals, all other fuel delivery related sensors (AFM, TPS, boost sensor, thermisters, etc..) are a straight DC voltage, no reference frequencies can be obtained from them, they have to be algorithmically mapped by the ECU before the results & fuel delivery outputs can be oscillated (or, switched to ground, if you prefer)...Now, at 3K, my primaries are doing something around a 22% duty cycle, which means no signal can be "delivered" (or changed) approx. 80% of the time. If we were to assume that the CAS signals "run the show", and that the injector pulsewidth can only actually be changed (compared to the previous pulse) when the coil is energized, we're looking at 25/.22, or 5.5 times per second (double this for 6K rpm, of course). Which, by the way, is almost exactly what the O2 sensor is showing me at 3K...
-Joe
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