086 | Closed Loop Fuel Control Link G4+

Hello Andre,

i just watched the webinar on closed loop lambda control on the Link G4+. Very informative but one question remains.

As you said, with new technologies as CAN Wideband, you now rely on lambda mesure to use the Auto mode. If you have a standard wideband (non CAN), do you still recommend to use this mode ? or to stay with the stoich mode ?

Thank you !

With a conventional wideband I'd be a little reluctant to use closed loop at full power. Alternatively if I was to allow full Cl control I'd be setting pretty tight limits for the trim - perhaps +/-3%.

Note also in the latest 5.6.6 firmware on our ECU's which have the CLL auto mode you can now enable two 3D tables to control the amount of CL trim allowed which makes it a little more safe. So for instance you can give the ECU authority to add or remove lots of fuel at cruise conditions but then at say higher boost only allow it to add fuel but not remove any...

Adam and Andre, if using CLL on boost also and doing like Adam suggested, what you suggest to put for TP Delta Lockout and MAP Delta Lockout values? Keep CLL on with transient throttle or not?

Hey Jani, I'd start with a lockout of around 5 kpa and 5-10% TPS. Just log the results and see how the closed loop is responding. What you're trying to do is prevent the closed loop from trying to correct momentary rich or lean spikes that result from transient conditions.

Thanks Andre, I will do that :)

Hi Andre,

Im a little confuse for the setting in FUEL Main about the open loop lambda table. I should turn it off or ON when im using the CLL function?

The ITB TPS tunning would be turning that on as the lambda target table will be the fuel calculation background(which fm my understande it just act exactly like the CLL function?)

tks

It doesn't specifically matter whether you've got the open loop lambda table turned on or off from the respect of running closed loop control. If it's turned on then the ECU will perform a background compensation to the delivered fuelling and the aim of this is twofold. First it will make the fuel table flatter which improves resolution, and secondly if the fuel table is tuned to achieve the open loop target then you can change the actual lambda the engine is running at from within the open loop target table. This is relatively close to how a VE-based fuel model works. If you're running a ITB/turbo engine then you will need the open loop lambda mode enabled so you can target a change in lambda relative to MAP.

In either mode you can use closed loop control and the open loop lambda table will be used as the target if you choose auto wideband mode.

Tks Andre, this really help to better understand the relationship of main fuel map, afr target and CCL