Syvecs Forums

Have got our first solaris car up and running properly. Now with closed loop fuel control, and also I have the close loop knock control working nicely!

Nice one
What engine are you using?

Hey Paul

Good to see you aboard chap and nice work with the S6

Are you using the closed loop fuelling on load?

Also what Gain control are you running with the knock control, as at present im picking up alot of noise with the 3sgte off boost.

Ryan

Good Work Paul

I am using closed loop fuelling on boost, but had to spend a lot of time altering the PI control to get smooth accurate transitions and corrections. The knock control also requires setup time.

Good work Paul - this sounds awesome from our chat on wednesday.

is there limits to the amount of fuel correction it will do and flag a faulty sensor if it breaches them?

Not that the wideband sensors when mounted in the exhaust seem to fail often but just a thought

Simon

Simon,

there is a limit to the amount of fuel correction that can be applied, with separate negative and positive limits. They are definable, so feel free to put in whatever values you consider sensible / are happy with

Lambda sensor fault detection is done on the lambda signal itself not on its derived parameters. There is a minimum variation which must be exceeded in less than the minimum variation time, if it isn't then the sensor is flagged as failed. This doesn't cater for the scenario where the sensor starts reading wrong, but the problem you have with that is trying to reliably determine whether the ongoing correction is due to the sensor or there is a problem with (say) the fuel pressure (if you don't have a fuel pressure sensor).

It is perhaps something that requires a little more thought, but perhaps you can see the dilemma ? Trying to reliably decide WHAT is wrong is difficult when you can't even predict what sensors a car will or will not have; there's no point in putting in a hook that says that if the lambda is reading lean but the relative fuel pressure is fine then it's most likely the lambda sensor, because a) you don't know that the car has a fuel pressure sensor and b) the lambda sensor may STILL be right (what if the cam timing jumped? the VE would change, so the appearance AFR would reflect this, ergo you could end up flagging a perfectly good sensor, than in this instance may save the engine, as being faulty, which could be disastrous)...

Hope this makes sense,

Pat.

Pat,

Thats great, thanks.

High and low limits etc is good.. in some ways I like the idea of closed loop fulling on boost and in otherways I don't
I presume the high and low limits are not configurable dependent on load/boost?

cruise you are unlikely to damage anything..

Simon

Simon,

there are two sets of limits on the final correction, based on TPS. There is a normal limit, and a full throttle limit, which limit is applied depends on whether TPS exceeds a definable threshold or not. I suppose it might be possible to add a MAP dimension to the minimum / maximum final correction limits, but not sure whether that makes sense or not, due to reasons listed above....

Cheers,

Pat.