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Engine protection question

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Hey guys.

Looking through the software last night to see how the engine protection is done for fuel and oil pressures, read the help file and seen that you use gp limit for oil and fuel pressure.

Noticed on mine(thunder), there are 2x gp limits... gp limit1 and gp limit2 (under engine protection )... my question is, what if you need a 3rd gp limit? Say i have oil and fuel pressure setup for those two limits, how would i setup a 3rd limit for say lambda/afr? Is there a seperate limit for AFR?

Just trying to figure this out before i decide which parts i would want for protection etc.

Cheers.

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Yes ok, so your covered for the oil and fuel pressure protection ( which is what i was saying i found out ).. but say you want AFR protection as well? Wheres the 3rd gp limit???

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Literally just went through this last week setting all of mine up. You have to choose between fuel pressure and AFR because oil occupies one of them and you wouldn't skip that. My take-away from it was that you can cover a lot more issues (such as injector failure rather than just fuel pressure failure) by doing AFR protection rather than fuel pressure. 

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Note you can also make your main RPM limit table 3D to add extra parameters.  Fuel pressure protection for instance if you use Differential pressure it should be relatively constant under all conditions so you dont need a full 3D table - you could just put it on one axis of the RPM limit table. 

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If you dont mind it being a bit harsh, you can "chain" virtual aux's with as many parameters as you want, and set this virtual aux as the trigger for any kind of engine protection you want (either RPM limit, or the trigger to swap to a low power ignition/ethrottle table, etc). Its a straight on/off though so if you want it to fell graceful you have to set up the "safe" table to have something like usable values up to 2-3k rpm or 10% throttle and "limit" values above this.

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Just posting back on this one - I went in and had a crack at adding a 3d table into my MAP Limit with a Y-axis for differential fuel pressure as suggested by AdamW. Thanks for the mint suggestion. Means I have Fuel, AFR and Oil covered. 

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On 5/20/2018 at 5:25 AM, Adamw said:

Note you can also make your main RPM limit table 3D to add extra parameters.  Fuel pressure protection for instance if you use Differential pressure it should be relatively constant under all conditions so you dont need a full 3D table - you could just put it on one axis of the RPM limit table. 

Wouldn't there be an issue with using the main RPM limit with an input such as fuel pressure? I could see that a small, momentary dip in fuel pressure would cause the limiter to be activated. And when the fuel pressure returns, the limiter would be very quickly deactivated. In other words, you would want a delay for entry and deactivation of a limiter based on any analog input. I haven't tried this, but I would like to, which is why I am curious. I see that using a GP limit allows for a delay and "Exit Decay Rate" that could work those out. 

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13 hours ago, Stevieturbo said:

You can set a time delay before it activates.

 

It would seem sensible in the engine protection section....to actually have basic engine protection features though.

I don't think you can set a delay on the main RPM limit. And even if you could, you wouldn't want that. That's your main RPM limiter. 

 

+1 to improvements in the engine protection side. At least a couple extra GP tables would help a lot. I'd rather see tables with the Z axis being your protected variable; with engine protection coming in if that variable is exceeded, with a delay for engagement and disengagement. Doing that would allow for user defined variables on the x, y and z. But I realize that it would be a lot of work to go away from RPM limiter method. 

Also, I am missing the AFR Error (Actual - Target) parameter that I am used to on other ECUs.

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All this is already possible. I use oil pressure, differential fuel pressure and lambda as extra limits on top of the basic features. And yes there is a delay available.

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On 6/26/2019 at 1:28 PM, cj.surr said:

I don't think you can set a delay on the main RPM limit. And even if you could, you wouldn't want that. That's your main RPM limiter. 

 

+1 to improvements in the engine protection side. At least a couple extra GP tables would help a lot. I'd rather see tables with the Z axis being your protected variable; with engine protection coming in if that variable is exceeded, with a delay for engagement and disengagement. Doing that would allow for user defined variables on the x, y and z. But I realize that it would be a lot of work to go away from RPM limiter method. 

Also, I am missing the AFR Error (Actual - Target) parameter that I am used to on other ECUs.

I never stated to try and delay the main rev limiter.

 

I said you can delay the onset of the generic gp rev limits.

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On 6/28/2019 at 8:21 PM, Stevieturbo said:

I never stated to try and delay the main rev limiter.

 

I said you can delay the onset of the generic gp rev limits.

I was referring to using the main RPM limit as a safety for additional parameters, as was suggested below. 

On 5/20/2018 at 5:25 AM, Adamw said:

Note you can also make your main RPM limit table 3D to add extra parameters.  Fuel pressure protection for instance if you use Differential pressure it should be relatively constant under all conditions so you dont need a full 3D table - you could just put it on one axis of the RPM limit table. 

 

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When I first looked at protection method I was surprised not to see it as described above. Below set point against rpm = cut simples 

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