Yes I most definitely want to do those very tests and report the results for you guys. I have the whole bench setup/procedure in my head and I also want to try PWM frequency as another variable. All I need is a way to bench trigger the solenoid.

So I had another thought on that. Joe maybe you can help. As mentioned previously I found a shareware PC app that creates a PWM square wave with variable frequency and DC. So, is there a quick circuit I can rig up with a transistor that would switch the transistor in response to what is essentially a PC audio out (headphone jack) signal? It would have to handle about 12W (P=V^2/R) at 100% DC on the load side. I would just have the transistor either switch to ground or switch to 12V DC, and vice versa the other end of the solenoid coil. I think 300 Hz would be the highest freq I would even think about trying, more like 200 Hz which is what I believe the valve is rated for. Too fast/too many cycles for a mechanical relay but no problem for solid-state.

This has to be a pretty simple analog circuit I can build with cheap Radio Shack parts right?

Cheap and radio shack parts don't belong in the same sentence ;)

I'm not disagreeing here. Honestly, I'm having a hard time visualizing the effect of this arrangement. It will certainly contribute to turn-on lag, but I don't know what its steady-state characteristics will be. That's why I think a test will be valuable.

Yeah I know their stuff is really inflated. :)
But if it is only $20 worth of crap I'm not worried enough about price to go to digikey or the like.

Agreed. One good test is worth a thousand expert opinions. Give me a good circuit design and I should have it up and running pretty quick. I cannot work on this this weekend, but next weekend should be no problem.

Something like this would work: DPRG: A Simple PWM Circuit Based on the 555 Timer

Agreed. But assuming that the PC PWM output approach works then all I really need is the right-hand part of the circuit, right? That is, the transistor and whatever resistors etc. to support it. I know squat about transistor switch circuits. I could google and read up on it but I am hoping someone knowledgeable can save me that trouble and sketch something up off the top of their head.

The audio method you speak of would trigger the irf fet. You would need that and a dc power supply that can handle 12W. Also might need a heat sink on that fet. For power supply, if you have a pc power supply sitting around that would work perfectly.

this is the datasheet for that FET: http://www.audiolabga.com/pdf/IRFZ46N.pdf

You will at least need a diode (unless you care to fry your headphone jack) and probably a 1k resistor as a load to make it switch to the headphone jack. I'm not sure what kind of signal you'll get out of it. You might want to use a scope to see what the app will produce and compare it to the FET datasheet.

Wait...

You're planning to drive this with your Adaptronic, right? Can't you just do that?

Well I considered that but that is inconvenient for a few reasons. One I do not have a spare harness for it, and two, I do not have a means to stimulate it, like a jimstim or whatever the MS uses. I am not sure that I can get it to fire the outputs with the laptop tuning software with no trigger inputs. I am going to look into that though.

Oh. I assumed that the Adaptronic could generate its own free-running sync pulses for injector testing like the MS2 can.

Even still, assuming it's currently wired up and running (the Adaptronic to the engine, I mean) you could just run the one extra wire for the HSV and simply extend the wire over to the bench. Have somebody hold the engine at a constant speed, set the HSV drive to whatever setting you want to test.

Oh Snap! Was that a shot across the bow from the MS camp? :giggle:

Well, one, the engine is not even in the car right now, and two, I want to be able to run it independently of the vehicle. I am working on something that would require testing in a lab with no car.

ZX-Tex you're better off using the parallel printer port rather than the headphone output.

The headphone output will have a hipass filter output so the pulse train will be very distorted. Itll be a pain to build a circuit that can correctly read it to drive the MOSFET.

Good idea but the shareware software I found generates an audio signal.

I had a friend build me a very simple transistor circuit once that plugged into the headphone jack (audio signal) on a radar detector. No PCB board, just wires, solder, resistor, transistor can, maybe a diode, and shrink tubing. Built it in less than an hour with parts lying around the lab. It triggered a bright LED cluster whenever the radar beeped. I used it so I could see the radar detector go off when riding my bike (too loud to hear) and it worked great. I basically need a higher wattage version of the same thing. I'm tempted to use that setup but am thinking I might overload it.

Unfortunately that guy, an uber electronics tech, is not around here anymore so I can't tap his skillz for this. I was hoping one of you guys was uber enough to duplicate his deed :)

Ok, here's what you do.

You've got the Adaptronic itself, right? Since it's not capable of doing something that a $200 ECU based on a 25 year old 8 bit microcontroller with 512 bytes of RAM can (Ok, that's the last one, promise), we'll help it along.

Hook the HSV up to the ECU. Configure it for a single 36-1 VR crankwheel. Then, download the software and build the circuit on this page: Crankshaft Timing Signal Wheel Simulator

For the transformer, you don't need to order from Digikey. RadioShack P/N 273-1380 will suffice. You can ignore the transistor and resistor- all you need is the 1/8" plug and the transformer.

With this, you can drive the Adaptronic to any RPM. I assume you know how to simulate various MAP conditions on it.

or you could just build the 555 timer circuit...

+1

or is that, +555 = 1110.

SMACK! :owned:
Good thing it has some other awesomeness to compensate for this relative weakness.

OK I am liking that. Cheap, easy, freeware driven. I do not think I will even need the MAP sim to get this to work since the PWM output can be proportioned to whatever IIRC so I can just scale it from RPM.

I am late to this discussion and am only here to offer a little info on PWM water delivery in the ag sector. Case IH uses it on their patriot sprayers. It is called AIM Command. It might give you some ideas. You set the pressure you want to deliver the liquid at and it adjusts the pw to match the desired spray volume vs speed.