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AFR Target


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Hello. Happy new year!

I did the basic fuel settings. Injector ID1050X. The engine runs on E30. But the fuel equation is still not completely accurate. If the AFR Target is 1 and then listed at 0.9, I'm still wrong to 0.86-0.87. What's wrong with the settings?

Tried to achieve the desired result through the Fuel Charge Cooling Coefficient and Charge Temp Correction. But unfortunately the attempts failed.


PC Datalog - 2023-01-4 9;47;03 pm.llgx SX 03.01.2023.pclx

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I will make the assumption that in the Injector Dead Time, need to choose the Differential fuel pressure, and not the absolute one. I'll check tomorrow. If anyone has any other thoughts, I'd be happy to hear.

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I notice you have really large VE numbers at idle and I have seen this before with a couple of other users with ID1050X injectors.  So Im suspicious that the ID supplied deadtimes may be a bit off when using Link drivers (they use Motec M1's for their characterisation). So you will probably find more error at idle and it will work better at higher loads.

A couple of things I noticed in your tune which changing will probably help this error a tiny bit:

  1. Your deadtime table has fuel pressure on the Y axis, it should instead be differential fuel pressure (Pressure across the injector is what affects deadtimes).
  2. I think the Stoich ratio for E30 should be more like 13.0, that is assuming Eth is 9.0 and petrol is 14.7 and we are using a 30/70 split between those.

I would experiment with increasing the deadtimes a little to see if you can get this open loop target correction working better and more realistic VE numbers around idle.  I would typically expect VE of 50-65% at idle, you have 78ish.   



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Thanks Adam. Yes, the stoichiometric proportion should be 13. Since there is no sensor and the alcohol was diluted manually, changing this parameter was also an area of study for the correctness of the equation.

Thank you very much for the tip about the distorted data Injector Dynamics

Tomorrow I will achieve the correct work and write what exactly was the problem

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I'll leave this here for future generations)

I managed to achieve following the AFR target at idle through the injector dead time . But in other modes, the engine did not work correctly. It did not react correctly to the throttle opening.

As a result, I filled in the factory values Injector Dynamics and entered a zero value for the fuel cooling coefficient. Under load, it worked quite acceptable.

Volumetric efficiency at idle was 80%, further from this value the map turned out without distortions. I don’t think these are correct values in absolute terms, but the Link G4X correctly calculated fuel over the entire rev range. 

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