Developers, please, more sophisticated injector staging!

[GintsK]

Currently we can trigger secondary injectors from TPS position only. ITBs.
It lead to undriveability at low Rpms. Because air flow trough trumpets is way too low.
Using just WOT TPS values can lead to lean at high rpms - partial throttle when primaries are maxed out.

In my opinion best descriptor for engaging secondaries should be duty cycle of primaries. It is proportional to flow velocity in trumpets.

But rpms AND TPS can also solve the problem.

Gints

[dnb]

Can we also have a small table to control injection angle?  4x4 RPM vs Load (MAP or TPS) would be fine.

[mattias]

The staging code suggestion of using duty cycle has been brought up, I believe it will be implemented in the first 1.1.7x  firmware.

dnb : Yes, I highly wish for injection angle code too. There is a lot of things to fix and test before it but I really want this for my own project since I have a high overlap cam profile and really want to get as smooth quality as possible,  facts : 4 mm lift @ TDC on BMW M20, 84x84 strokexbore, 42+36 mm valves.
We will see, I want it this spring.

[lugnuts]

Have any of you guys used staged injection with success on high powered drag cars?

I've never used staged injection with any ecu (yet).
I have an 8 second car on an old Autronic SM2 that uses 8 Bosch 160# injectors (2 per cylinder) full time.
I'd like to use VEMS with staged injection on this car, but it has to work 100%, no BS.

So who's using it, and how are the results?

[GintsK]

lugnuts, because of reason described above I was unable to use current strategy. So I managed running on secondaries with config switching. But tuning was nightmare. I used only secondaries at full load, because primaries was too big... Car is for rally-cross.

Mathias, most comfortable is determine injection phasing by end of injection pulse. Is it intended so?

[mattias]

Yes, the end of injection angle is the most important so that you can time the injection to be done before the intake valve closes - which is desireable with hot cams. On a fuel economy motor you may want to inject all the fuel on a hot intake valve before it opens. 
If you think about it, injection phasing works exactly like ignition dwell.

[lugnuts]

The current staging has TPS and KPA right?

This car sits at 5-7 msec. of injector time on the starting line, so I could stage the secondaries in before that at 3-4 msec when the injectors are nice and linear.

Methanol for fuel, it runs very intolerant of widely varying air/fuel ratios.

I can un-plug 4 of the injectors at idle and the car runs the exact same, ha ha.


Injection timing I would like in the future. But it seems the developers don't want to do it, and everybody else is scared of it (why do you want that?/one more thing for people to screw up comments) the same as when I ask who is using the cam sensor.

[lugnuts]

How do you account for the extra fuel when the secondaries kick in?

In my example - going from 1x 160# injector to 2x 160# injectors at let's say 150 KPA.

Would I simply reduce the VE table by 50% at 150 kpa?



How would your proposed duty cycle switch point account for this?

[GintsK]

I think it works like gradual reducing of required fuel constant when rate of secondaries grows-up.
I suppose VE should stay as normally is. If injector size is chosen correctly.

Or I am wrong?

Gints

[lugnuts]

I hope somebody can tell us for sure. I can't afford to find out on this customer's car. Everything needs to go smoothly or else I'll just keep the Autronic in the car.

[rob@vems.co.uk]

What you need to do is model the behaviour you want, and then show it to the developers.
A model can be an equation, some psuedo code defining the algorithm, some C code, or even a diagram or graph.