On Tue, 10 Jan 2017 14:53:31 -0800, wrote:


A 555 might be a good choice for providing the timing pulse but the
LM1949 is a purpose made injector drive chip so would be a good choice
for doing actual injector control.
Thanks David! I'll look at it.

You don't need a fancy driver for this application. 40 pounds/hr
pintles were used by the zillions in the 70s through 90 in jap cars. 4
ohm coil as I recall.

So the driver is thus. A 12 or 15 volt power supply with a
back-biased diode across it to protect from flyback, a 4 ohm 10 watt
resistor, the injector and a power FET with a 600 volt rating,
suitable current rating and logic level (5 volt) gate drive.

Here's a good transistor.

http://www.mouser.com/ProductDetail/...%2fRBY f2Y%3d

Note that I do NOT include a flyback suppression diode. Doing so will
tremendously slow the closing time. I instead rely on the high
voltage transistor and the ballast resistor.

I'm not a great 555 fan for industrial environments. crud buildup
will change their timing. I'd probably use one of the mini-Arduino
boards. Cheap and precise and I could write the snippet of code
faster than I could futz around with 555 resistor values.

And if you need the injector firing synced to an external event, say,
spray the work right before a flycutter gets there, an optical or
magnetic trigger is trivial to set up.

John
John DeArmond
http://www.neon-john.com
http://www.tnduction.com
Tellico Plains, Occupied TN
See website for email address