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Hardcoded lower TPS limit in ITB mode?
Posted: Fri Apr 29, 2022 3:34 pm
by tmbryhn
Is there a hard-coded lower TPS limit in ITB mode on more recent firmware versions?
Whatever I try, I can't seem to get the TPS lower than 1% on my dual ETB setup. It's quite frustrating when you have one 54mm throttle plate per cylinder and can't get the idle down without retarding the ignition way too much
Current tune and logs:
https://www.rusefi.com/online/?vehicleName=Aurora&user_id=1083&sorts[uploadedMsq]=-1&sorts[uploadedLog]=-1
Re: Hardcoded lower TPS limit in ITB mode?
Posted: Fri Apr 29, 2022 3:39 pm
by AndreyB
Re: Hardcoded lower TPS limit in ITB mode?
Posted: Fri Apr 29, 2022 3:56 pm
by tmbryhn
Is there a way to work around this lower limit? Through eg. Lua?
Or will there be considerations implementing a simple variable along the lines of "minimum TPS value" to be set manually in TS? Ideally with at least one decimal place so that one could enter eg. a value of 0,3%?
Re: Hardcoded lower TPS limit in ITB mode?
Posted: Fri Apr 29, 2022 4:00 pm
by AndreyB
Cannot lua, clamping happens after Lua.
Yes should be configurable
https://github.com/rusefi/rusefi/issues/4119 created your best bet is to chase Matt.
Re: Hardcoded lower TPS limit in ITB mode?
Posted: Fri Apr 29, 2022 4:50 pm
by tmbryhn
Thanks
Re: Hardcoded lower TPS limit in ITB mode?
Posted: Fri Apr 29, 2022 10:31 pm
by mck1117
How much timing pulling are we talking? Can you adjust the linkage so that 1% is actually fully closed, but not on the mechanical stop yet? The point of the 1% limit is to prevent jamming the throttle against the hard mechanical stop (same at the high end) to avoid integral wind-up.
Re: Hardcoded lower TPS limit in ITB mode?
Posted: Sat Apr 30, 2022 7:02 pm
by tmbryhn
mck1117 wrote: ↑Fri Apr 29, 2022 10:31 pm
How much timing pulling are we talking? Can you adjust the linkage so that 1% is actually fully closed, but not on the mechanical stop yet? The point of the 1% limit is to prevent jamming the throttle against the hard mechanical stop (same at the high end) to avoid integral wind-up.
We're talking into the negatives to get idle close to 1krpm.
What linkage are you referring to? This is a dual ETB/DBW setup.
Before updating firmware, it seems I was able to close it to < 1%, which resulted in a better engine brake during coasting, and also a more crisp/responsive return to idle speed. I'd really like to have the option of setting lower TPS manually to eg. 0,3% or thereabout. I don't think there should be a problem with integral windup on eg a 0,3% setting, given that I seem to have less than 0,1% positional oscillation on the ETBs, but I might be missing a point here..
One 54mm throttle plate per intake port on a 2332cc engine is pretty large btw
Re: Hardcoded lower TPS limit in ITB mode?
Posted: Tue May 03, 2022 6:01 am
by AndreyB
i think it's done please give it a try
Re: Hardcoded lower TPS limit in ITB mode?
Posted: Tue May 03, 2022 6:17 am
by tmbryhn
Downloaded and updated the ECU. Looks good.
The setting is clearly visible under ETB page in TS, although just as an integer and not float, so can't fine-tune the lower limit.
I'll try with 0% for the time being. Thanks for the quick update. I'll post back once it's tested
Re: Hardcoded lower TPS limit in ITB mode?
Posted: Tue May 03, 2022 6:50 am
by AndreyB
tmbryhn wrote: ↑Tue May 03, 2022 6:17 am
just as an integer and not float, so can't fine-tune the lower limit.
That's an issue - just changed it to allow 2 digits and spelled out 0.01 as minimal value