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alpa38
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Last seen: 4 years 7 months ago
Joined: 07/14/2014 - 13:12
Tuner and Infinity-6/8h questions

Sorry I modified my message several times.

I don't understand how Tuner must be used. For example

- which pins are used to control VVC

- why, when I select Throttle [%] for LS2_Duty X-Axis, I still get RPM values in the X axis.

- where are explanations of all tables, like what means "TC_TqReduceFuel [Cut %]"

- why the Mini Harness pdf seems to assign LS3 out for MIL, while wizard allows me to use any LS out for MILOutput functionality

 

Why specialized outputs like Injectors could not be used as GPO when the functionality is not used ? Same for inputs.

What is the rate of sensor sampling ? Especially for fast changing like MAP and TPS.

 

Bravo for the Tau (wall wetting) enrichment algorithm, it's finally used in aftermarket ECUs.

- where is defined the duration of the enrichment (leaning) ? Wall wetting is usually caracterized by the "evaporation rate" and "wall wetting fraction", both depending on MAP, engine temperature and flow rate. So how do you model the evaporation rate ?

- how do you calculate the decay rate of the enrichment ? Especialy because MAP data is always "old" and at low RPM the MAP change can be very fast.

- how are combined Z values from the two WallWetting maps: mul or add ?

- what's the scale "Map rate" ? kPa/s. kPa/revolution

Thanks

AEM_NS
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Last seen: 9 months 4 weeks ago
Joined: 06/06/2014 - 09:31
Assuming you have a PWM VVC

Assuming you have a PWM VVC solenoid and not on/off, you'd use a LS that has a flyback diode.  On an Infinity-6 these would be LS1, LS3, LS5, & LS6.  When you change a duty table reference axis, the software does not automatically populate breakpoint values for you.  It simply changes the reference channel.  Just type in the breakpoint values you'd like.  

TC and all the TC tables are well covered in the full instruction manual which you can download HERE.  Let me know if you have more questions after you've read the full manual.

As you can see, you can currently assign the MILOutput function to any of the configurable LS outs.  The mini harness pinout is a little dated and reflects a time when some certain functions were actually tied to specific pins.  It seems that we need to update our documentation.  

The firmware does not support reassigning injector outputs as general purpose outputs.  This also applies to some inputs like the digital inputs where some can only be used for cam/crank input and others can be used for on/off switch input.

Fast sensor inputs (MAP, TPS, etc) update at 10ms.  Slow sensor inputs (temps, etc) update at 50ms.

Our well wetting function is a culmination of different implementation strategies. The end result came out as being the most practical for setup and tuning and it may not be nearly as complex as the enrichment control you're familiar with.  The table values are simply airflow adders to the calculated MassAirflow channel and the two different WallWetting maps add together.  MAP Rate has no units really.  It's simply rate of change as "new" TPS value is compared to "old" TPS value every 10ms.

alpa38
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Last seen: 4 years 7 months ago
Joined: 07/14/2014 - 13:12
Thanks for the manual.

Thanks for the manual.

AEM_NS wrote:

Fast sensor inputs (MAP, TPS, etc) update at 10ms.  Slow sensor inputs (temps, etc) update at 50ms.

Our well wetting function is a culmination of different implementation strategies. The end result came out as being the most practical for setup and tuning and it may not be nearly as complex as the enrichment control you're familiar with.  The table values are simply airflow adders to the calculated MassAirflow channel and the two different WallWetting maps add together.  MAP Rate has no units really.  It's simply rate of change as "new" TPS value is compared to "old" TPS value every 10ms.

I'm sorry but I'd like to understand how the enrichment should be tuned.

I'm used to a Tau system in which I define the evaporation rate and film fraction depending on MAP and temperatures.

Film fraction is a percentage (x10 of % in my experience) of the fuel flow while your maps define a value to Add to the flow. So to me the only possible choice is to use MAP on one axis and RPM on another, as flow depends on MAP and RPM. However I also need a correction by temperatures, which is in theory is a fraction as well, while here I have to define an Adder.

Using Throttle Rate on an axis brings us back to the usual TPS rate system which however defines the enrichment duration and decay rate.

Duration: in my experience the evaporation rate can be very slow even at high RPM, x0.1s, which is consitent with values we put in the usual TPS rate based enrichment system. TB change can be very fast, 50ms from idle to full throttle, so I can not enrich only while TPS is changing. I could inject a huge amount of enrichment to make it last a long time however once again I'd need a fraction, a multiplier, not a value to add.

Thanks

alpa38
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Last seen: 4 years 7 months ago
Joined: 07/14/2014 - 13:12
I looked at examples coming

I looked at examples coming with the Tuner and it seems like you use everywhere 'throttle rate'.

So correct me if I'm wrong your 'throtlle rate' system is a different version of the usual TPS rate system (usually called accel enrichment):

- usual TPS rate: defines enrichment level and its duration with a decay (which is a simplified model of the wall wetting theory)

- your throttle rate: when a TPS change is observed you inject a massive amount of fuel which is expected to stick to walls and evaporate during some time (depending on the engine), the wall wetting reservoir is defined by the overfueling and not by a delay. For the rest it's the same.

To me the difference between "accel enrichment" and "wall wetting" is that wall wetting deals with ANY change of fueling: MAP, RPM and temperature whatever injectors, cams, intake and boost, as long as ports remain the same. Basically you don't have to remap wall wetting when you change these components. Deal with any change means keep on enriching in hard accelerations WOT because boost climbs, don't overfuel when both TPS and MAP change (which will probably happen if TPS rate and MAP rate enrichments are added together instead of being multiplied).

WallW2 being stuck TPS_rate/Eng_Temp the only usable choice I have is to use TPS_rate/RPM in the WallW map.

AEM_SB
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Last seen: 12 hours 57 min ago
Joined: 06/07/2014 - 14:29
One of the design goals of

One of the design goals of the Infinity system was to simplify the 'basic engine tuning' aspects, with the hopes this would allow people to spend less time getting the engine to run and more time configuring advanced functions. WallWetting is an example of this, the table is intentionally quite simple without a separate option for decay factor. Combined with the ECU's other fueling calculations, this has been tested and confirmed to work well on many vehicles. The name 'WallWetting' was chosen to avoid confusion... previous AEM products used the name 'Accel Enrichment' to represent simple pulsewidth multipliers, and we wanted to clarify that this new WallWetting table is not the same as those previous products.  Since the WallWetting table values get added into the airflow side of the ECU's calculations, WallWetting values do not need to be adjusted after changing injectors. Using additive math rather than a percentage multplier means the WallWetting values are much less dependant on the numbers in the VETable. When using percentage multipliers for accel fuel calculations, it is very easy to cause a transient fueling problem by making adjustments to the steady-state fueling.

I hope you get a chance to test this for yourself, the differences can be difficult to convey via typed messages on the internet. People who have used this system should be able to confirm you will not need to spend much time adjusting the WallWetting tables to acheive good throttle response.