There are a few other issues. There is a mode that increases the idle to a pre-determined amount to anticipate the extra load of the AC, and I bet the PS pump load is also involved. Also my guess is this circuit is turned off once the idle switch is tripped, but not at full throttle. Once all these factors are taken into consideration, you end up with the brainy looking think that VW made. Hopefully some has the time to engineer this thing. THe VW digifant Jetta 88-92 has this built into the ECU, and these are plentifull, and cheap. I'm tempted to try this injection on a water boxer. ERic Pensioner wrote: >Perhaps not so mysterious a design. Your tachometer uses a pulse per unit >time to voltage conversion no digital stuff here nor D-A conversion. So if >the transfer function of pulses per unit time to voltage is known and the >desired range of ppt is known then the range of voltage is known. A >comparator circuit can give you a measure of whether the voltage is within >the specified range. If below then you have a signal that indicates engine >speed too low. If above then engine speed too high. Detailed design left >to David B or those with that sort of "bent". > >Pensioner > >Tau Beta Pi (bent), Eta Kappa Nu, Phi Kappa Phi in EE/CS, O so long ago. > > > > |
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