Peak And Hold Low Z Injector drivers

[jbelanger]

Colin,

You don't "need" the transient suppression diode but you certainly want it because otherwise you'll have sluggish injector closing. And the p&h circuit will behave more like a saturated injector from a flyback point of view so you shouldn't have a problem with heat. It's still a good idea to keep an eye on the diode to make sure that it's the case.

Jean

[Sprocket]

Ecu is back in the car and running. Before I swap over to the peak and hold drivers, i have changed the config of the injector. The required fuel value has been doubled and the 'divider' in injector settings has been set to 2. At idle i havent noteced any major difference, so its a matter of testing that and letting the VE learn settle the VE map acordingly. I'll have a play with the acceleration enrichments to see if this change improves that situation, which is the main reason for the change really. I'll do that tomorrow evening.

Once thats done, i will rewire the injector and set up for the peak and hold driver. Hopefully the VE map will be close enough allowing EGO correction to do its thing again using VE learn to settle the VE map. Hopefully have this done by the end of the week

A question for Jean. On the P&H board there are six solder pads, four for the injector driver signal, one for 5v+ and the other is presumably ground. Will it matter that i have not connected this ground? I connected it as per the previous version boards that did not have this ground.

[rob@vems.co.uk]

Excellent work.

[Sprocket]

Been out with the new injector config as above, and everything is good, lol it was fun to get out in the Mini and remember how well it pulls

PW at idle is now about 2.4ms and max 11.5ms at 52.5% duty. The injector's potential is now starting to be used

Its amasing how many ways there are to achieve exactly the same fueling

I have also tuned the idle Lambda to 1.04 and fast idle to 1.02, you know why The idle seems much smoother now, though its difficult to tell as i've not had the engine running for a while.

Never got round to looking at the acceleration enrichments, but its about the same as before, still some work required there.

Coolant temps have settled out and no longer fluctuate stupid amounts, so i think thats fixed to a degree, still need to get the INC files for these sensors compiled into HEX format.

Next stage now is the swap over to the peak and hold driver. I'll rewire the injector tomorrow evening, its only a matter of running a wire from the Injector output to the injector, I'll leave the other wire with the series resistor where it is and just disconnect it at the injector for now. Testing will start on Wednesday.

Looking at the injector ramp up times, i was thinking of starting with 800 and starting from there ?? remembering this is a low ohm injector with the peak and hold driver, the injector will open fast. Im currently using a ramp up time of 1296

Onwards and upwards

[jbelanger]

A question for Jean. On the P&H board there are six solder pads, four for the injector driver signal, one for 5v+ and the other is presumably ground. Will it matter that i have not connected this ground? I connected it as per the previous version boards that did not have this ground.

Actually, it is essential to connect the ground pad because that ground is for the LM1949 supply. The pad was added because I have separated the low-current ground from the high-current ground on the board to minimize any noise issue (not that there was any reported with the first design but better safe than sorry). So connect this ground pad to a known ground on the VEMS board (preferably not a ground from a high current component).

Jean

[Sprocket]

Thanks Jean, no worries, i'll do that tomorrow as well

I had a feeling, thats why I asked the question

[Sprocket]

 

It works

Injector ramp up is set at 552 at the moment and idle is good. Warm up enrichments and idle air need tuning fully again. VE map isnt far off, and the agressive VE learn i have set, is pulling it back fairly quickly. Its just down to tuning now.

Id like to thank those for their help, especialy Jean for taking time out to get involved.

Ive even started to use the Wiki a bit more and started to update my MembersPage

[jbelanger]

Good work! 

And I'm glad I could help. It's always nice to see people trying new things and succeeding.

Cheers,
Jean

[jbelanger]

Colin, do you mind if I put a link to your wiki page on my web site?

[Sprocket]

Hi, Jean, yes, that won't be a problem

http://www.vems.hu/wiki/index.php?page=MembersPage%2FSprocket%2FPeakAndHoldInjectorDrivers

[rob@vems.co.uk]

Just a thought


I'd be using a hot glue gun on all the connections to the board - it will add mechanical strength and insulation to those joints, I'm not dissing your soldering but vibrations kill connections, which is one of the reasons we avoid daughterboards where possible.

It will be interesting to see how this works I can think of a couple of cars that would benefit from removal of resistor pack and addition of one of these boards.

Rob

[jbelanger]

I'd be using a hot glue gun on all the connections to the board - it will add mechanical strength and insulation to those joints, I'm not dissing your soldering but vibrations kill connections, which is one of the reasons we avoid daughterboards where possible.

It will be interesting to see how this works I can think of a couple of cars that would benefit from removal of resistor pack and addition of one of these boards.

Rob

That's a very good point and I totally agree. You want to remove as much stress on the solder joint as possible.

Rob, let me know if you have any question regarding those potential installs.

Jean

[Sprocket]

Valid point

I'll get the glue gun out this week