Does anybody know how water injection pump flow-rate is controlled?

Pulse Width Modulators?

 

Or do they use a variable flow meter on the water supply, and the pump is just an on-off switch?

 

We'll try this here for a little while to see if it get's anybody can answer your question.

 

I assume your refering to water/meth?

From everything I have seen and read, the flow into the intake is all on injector nozzle size, and the pump pressure rating, so supply 12 volt to a 220psi pump its gunna spray 220 psi?
So I spose the pump is effectivly an on/off switch itself?

 

Well, that would be the crude yet effective way a lot of guys do it; the pump turns on, putting water through a nozzle. Some guys have solenoids that open up multiple nozzles according to boost readings.

But according to literature from Snow (page 11), they have a black box where you enter in a boost value where it starts spraying and a boost level where it stops spraying, and then the box will somehow tell the pump to gradually increase the amount sprayed between those values. They say that it affects the "injection pressure" of the pump.

I would like to know what the output of the black box is, so that I could figure out how to control it via laptop.

EDIT: Alright, Snow replied via email and said that the pump has an integrated PWM; so the pump's pressure remains constant, but it turns on and off really really fast. And the signal from the black box, which I assume would be voltage, tells it how fast to pulse.

I would just ask them what the signal parameters out of the black box are, but they might not reply... Ahh, what do I have to loose?

 

I would tend to think that this would be a better "general Diesel" thing, but I did get a response within 3 hours after you moved it, so what do I know?

 

Thats true, I forgot about the "black box".
I have to agree, might want to stick this the "general diesel" section.