5th injector circuit (fuel or water)

[Simon Quested]

Hi All 

I sent this on tuesday but it didn't seem to get through... the word doc is 35K maybe I typed to 
much and went over the 40K limit, I will send the circuit diagram separately.

I would appreciate it if you guys could have a look at it and pick any faults before I prototype it.

This is how it should work...... I hope =-)

Map output feeds into OA 1 & 2, this is the voltage to pulse width converter part of the circuit 
(from the op amp cookbook), as map voltage increases injector on time increases. The 555 
sets up the trigger pulse for the voltage to pulse width converter. OA 3 sets the threshold 
voltage from the map sensor. OA 4 does the same for the O2 sensor. The 3 input and gate 
ensures that the 5th injector will only come on when 1) map voltage is higher than the set 
threshold voltage 2) O2 voltage is lower than the set threshold voltage. This should mean that 
the 5th injector will only come on under boost and when the mixture is starting to lean out.

I'd like to use the same idea for the water injection minus the O2 sensor.

What should I use for Q2 I was thinking a big power transistor, can anyone tell me either the 
part no. of any injector drivers or where I fond some data on them. What base freq. do injectors 
run? 

Please feel free to use/modify my circuit for personal use and if you make it better I'd like to 
see the changes. I think that between all of us we should be able to make a good simple 
5th injector system.

Cheers

Simon

PS before you mail me saying I didn't attach the circuit I mailed it by it's self
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  Simon Quested (E-mail questeds at lincoln.ac.nz)
  Computer Technician, Silicon Graphics & Windows NT Support
  Centre for Computing and Biometrics
  LINCOLN UNIVERSITY OF NEW ZEALAND
  Phone (64)(03) 3252811 Ext. 8087
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http://www.lincoln.ac.nz/ccb/techs/simon/default.htm
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Some people can tell what time it is by looking at the sun. But I have
never been able to make out the numbers.
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