Hardcoded lower TPS limit in ITB mode?

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tmbryhn
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Hardcoded lower TPS limit in ITB mode?

Post 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 :lol:

Current tune and logs:
https://www.rusefi.com/online/?vehicleName=Aurora&user_id=1083&sorts[uploadedMsq]=-1&sorts[uploadedLog]=-1
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AndreyB
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Re: Hardcoded lower TPS limit in ITB mode?

Post by AndreyB »

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tmbryhn
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Re: Hardcoded lower TPS limit in ITB mode?

Post 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%?
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AndreyB
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Re: Hardcoded lower TPS limit in ITB mode?

Post 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.
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tmbryhn
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Re: Hardcoded lower TPS limit in ITB mode?

Post by tmbryhn »

Thanks :)
mck1117
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Re: Hardcoded lower TPS limit in ITB mode?

Post 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.
tmbryhn
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Re: Hardcoded lower TPS limit in ITB mode?

Post 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 :lol:
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AndreyB
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Re: Hardcoded lower TPS limit in ITB mode?

Post by AndreyB »

i think it's done please give it a try
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tmbryhn
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Re: Hardcoded lower TPS limit in ITB mode?

Post 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 :)
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Re: Hardcoded lower TPS limit in ITB mode?

Post 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
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