Does anyone know of a fuel injector driver that can take an existing peak n hold PWM and control an additional 2nd injector? I know of the 034 Motorsport unit and the AEM driver but they do FAR more than I need or they can't tap off of a current injectors PWM as their trigger input. Any help would be appreciated.

Updated concept from 11/18/07

 

if response time is not critical. why one convert your "P and H" injector to a saturated type by putting an inline resistor pack. The ECU should be able to drive an additional injector (~1A).

 

This is actually what I have been working on all last night. I am going to make a simple transistor pack which will only draw roughly 1-10mA from the stock injector for my trigger source and have 2 outputs, saturated with a straight thru connection and a P'nH connection which goes through a 10 ohm resistor. This way myself (or anyone else who wants to do something similar) can use either style injector with ease. I just need to make sure I have roughly 5 amps of current draw available. Haven't made a circuit design in many years now so I'm googling all the info I can right now :-). Thanks for chiming in Richard, viva la aquamist!

 

I'm having the worst time trying to create this schematic. Anyone know an electrical engineer on the forums who wants to make a few bucks and help me draw this thing up?

 

I do it for 2 bucks

 

SOLD! lol IF you are serious I will give you the circuit specs and you can work some magic for me. Paypal will be forwarded lol.

 

I want dollar bills. I cannot do the raw PnH circuit but I can recommend a driver chip. I can only do the non inverted saturated driver.

 

This one is free.

 

Made by National semiconductor Corp - search their site for more details.

 

Pshh, I was gonna go even simpler than that with a straight up darlington pair transistor configuration for a basic saturated setup.

I don't want to draw more than 100mA from the stock injector ground trigger and I need it to simply reproduce that signal (would cycle on and off at less than 70hz so thats a non-issue for most transistor setups) at 12 volts with a maximum current capacity of roughly 5amps@12.5ohms. I can add the resistor pack inline with that circuit later on.

I have it mostly setup but since I am triggering with ground circuits and such I assume its better to use PNP transistors. I'm verrry rusty with this stuff. (getting old I suppose,lol)

 

Just wanted to say that I designed the setup and it works like a charm

Needed a PNP transistor, NPN transistor, a few resistors and diodes and....bam, additional injector driver

Thanks anyways Richard.

 

Richard, empty your PM mailbox...its full. I just realized I drew the PNP transistor backwards in the last drawing. Glad I don't follow my own schematics,lol.

Richard is the MAN! Thanks for helping me refine my layout man, means a lot to me.

 

So it seems that no one makes injectors that can withstand water or alcohol on a continuous level (made of 100% stainless stell mainly) without corroding. As Richard already knows, people use a high speed valve system in a stainless steel flow chamber to simulate the task of the fuel injector. To limit the flow you just add the appropriate nozzle tip. The only two I know of are these:

CoolingMist S-HSV $169
PWM Frequency 300 HZ to 15,000 HZ
Up to 330 cycles per second
Amp draw .49 AMPS (Per 2 valve manifold)
Voltage : 0 to 12 V DC
Resistance: N/A



Aquamist HSV $255
Cycles up to 250 times per second
Resistance: 13 ohms
Still researching its other specs

 

Jamie, like to help on your research...

The two valves are completely different.

Coolingmist uses a Proportional valve - respond to current change or chopped DC.
Aquamist uses a PWM valve - respond to PWM pulses identical to the fuel injector.

If you like to know how a proportional valve works, go to the link below:
Clippard Electronic proportional valve: EVP made by Clippard
(please note Cooling's valve may not be sourced from Clippard.

 

So yours is voltage controlled and theirs is current controlled. Well I designed my circuit to be PWM controlled via voltage, I guess yours is the better choice.
Few questions:

What is the resistance and current draw of your HSV???

What is the shortest and longest pulsewidth it can recreate (in milliseconds)?
Can it go all the way up to static just like an injector or would this be too much of a load?(simple curiosity)

Maximum flow at any given PSI rating?



I think I am going to replace the standard shurflo pump with a walbro 255lph high-pressure inline pump (as long as it is alcohol safe). The biggest thing i am trying to accomplish is to be able to have the fuel pressure rise at a 1:1 ratio just like the stock fuel system. This way, the fuel flow stays at a consistent ratio as the air pressure increases.


I gotta say, you help out more than I would ever has guessed on my project. I'm basically figuring this stuff out eon's after you already did,lol. Being a DIY'r can be a blessing and a curse sometimes lol.