EBC boost solenoid via ignition IGBT output ?

[ZoLtaR]

I have lack of outputs. My setup is VR6 with fully sequential ignition (COPs) and injection. All injection outputs are connected to 6 injectors and 3 wire IAC. I have 2+6 ignition configuration so I have 6 logic level outputs connected to VAG active coils and spare 2 IGBT outputs. Can I drive EBC solenoid (pierburg from vems shop) thru this outputs? +12v feed for EBC should be connected to pin23 flyback or it is not necessary when driving thru IGBTs? It is possible at all?
Thanks for your help.

[MWfire]

Yes, you can. Just add low voltage flyback(by500-1000 or similar diode) from +12V to neg pin of solenoid.

[ZoLtaR]

I have some spare 1N4007 diodes that came with vems? Can I use them or it must be BY500 ?
And can I feed +12v for this solenoid from injector/IAC common +12v (connected to flyback 30V onboard) or should I use direct feed from battery (via relay) ?

[MWfire]

You can feed from injector also from battery, no problem.
Try 1n4007, it'll work ok.

[GintsK]

I would say it is not necessary to use any flyback clamping here if IGBT is used. 
Low voltage flyback clamping with diode significantly slow down solenoid closing reaction. And we do not want it.
And there is nothing in this path what can be hurt with high voltage spike.

Gints

[MWfire]

I allways use with low voltage flyback(constant current thoru solenoid) and works very good.

btw diode isn't for protecting output driver.

[GintsK]

Low voltage flyback is perfect for idle valve where we want to keep it opened by itself. But why here?

Here we expect direct pwm reflection on pneumatic action. If we put here diode - valve closes slowly. Higher frequency we set higher deviation from desired we get.

Gints

[GintsK]

Or you manage to use solenoid not as on/off valve but as variable restrictor?

[GintsK]

I just tried it on by bench using Pierburg valve.

With default 21hz frequency working range (valve still audible ticks):

with 30V flyback - 7....92%
with 1N4007         6...75%

31hz:
30V                    40...95%
0V                      40...81%

10Hz
30V                     5...97%
0V                       5...83%

So IMO low voltage flyback just makes resolution worse.

Gints

[ZoLtaR]

So +12v from common injector/iac feed and negative pin of solenoid directly to vems igbt output ?

[GintsK]

Yes. I've done so before. It works.
Low voltage flyback is good for devices where controllable position desired: IACV, VVT flow dividers.
In my test with Pierburg it was impossible to get intermediate position between fully closed or fully opened valve. Even with >300Hz frequency.
But may be I heave missing something important? MWfire?

[MWfire]

Yes. I've done so before. It works.
Low voltage flyback is good for devices where controllable position desired: IACV, VVT flow dividers.
In my test with Pierburg it was impossible to get intermediate position between fully closed or fully opened valve. Even with >300Hz frequency.
But may be I heave missing something important? MWfire?

I used so far allways with diode. I'll try on my car without and compare results of boost control(overboost ...)