supra5677
Pro
Posts: 1279
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posted September 22, 2009 09:46 AM
ZX12R HACKING QUESTION
To Members:
Ridge Racer programmed my ecu back in 2006. Now I want to add some closed loop functionalityto it.
What I am wondering is can we use the existing sensors for our bikes (example water temp sensor, or ram air pressure sensor) and swap it for a wideband sensor. I'm trying to make a poor mans closed loop system. Can this be done?
Brian
   
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tcchin
Zone Head
Posts: 867
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posted September 22, 2009 03:36 PM
I assume that what you want to do is monitor O2 content in the exhaust and have the wide-band lambda voltages drive a fuel offset map to manage mixture strength in the same way that an engine coolant temp sensor drives a fuel offset map to compensate for engine temps.
I can see this working if the base maps are off by a consistent amount across the whole range of TPS and RPM. That's how the ECT tables work, and that's how they're applied to a nitrous switch application. However, using that mechanism in real time to adjust mixture might be problematic. The rate of change in the ECT is glacial compared with that of TPS and RPM in real time.
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supra5677
Pro
Posts: 1279
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posted September 22, 2009 03:41 PM
Yes sir. This is exactly what I want to accomplish. What about the air temperature sensor?
Also what are ECT tables?
And what is the rate of change in the ect vs tps in real time? What is the percentage change and how much lag?
Is it possible to swap the air temperature sensor for the oxygen sensor to adjust the fuel maps?
thanks,
Brian
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tcchin
Zone Head
Posts: 867
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posted September 22, 2009 04:32 PM
ECT tables are Engine Coolant Temp tables.
Once a motor reaches normal operating temp, the rate of change of the ECT is several orders of magnitude lower than the RoC of RPM/TPS. Think of blipping the throttle while downshifting into a turn on the brakes: Has the ECT changed much? Probably not, yet RPM and TPS have been all over the place.
Air temp is kinda the same thing. It's not a parameter that the ECU uses for rapid mixture compensation because air temp doesn't change that quickly. Rather, it's used to apply an offset to the mixture over relatively long periods of time. In fact, many automotive ECU's don't adjust mixture on the fly using lambda sensors - they only use lambda data to trim the mixture under steady-state cruise conditions.
I understand that there are new products out there like the PC5 that claim to do auto-tuning, but there are two things working in their favor: 1) The electronics are 10 years newer, and probably have more processing speed and storage than a room full of stock ECU's; 2) Those devices can edit their maps on the fly and then store them with the updated values. This means that the offset values don't need to be deduced from sensor data every time they're needed - they're just read from a table. I'm sure the process of building a PC5 map is incremental and iterative, and that the device is not trying to reconcile sensor and map data while editing tables and adjusting mixtures in real-time.
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2000redrocket
Pro
Posts: 1662
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posted September 22, 2009 05:44 PM
they learn the map from what you tell it what you want the afr to be at that rpm and tp (at least on the mottys afr tuner) i remember you have a option to save the map or discard it. as stated they do a lot.
i would add one of them over coding the stock ecy to run the bike real time. i do not think any one would take the time since we do not have busas.
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tcchin
Zone Head
Posts: 867
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posted September 22, 2009 06:16 PM
quote:
i do not think any one would take the time since we do not have busas.
True dat!
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2000redrocket
Pro
Posts: 1662
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posted September 22, 2009 07:04 PM
i hate when i am correct.
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supra5677
Pro
Posts: 1279
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posted September 22, 2009 07:44 PM
Can the air temp tables be re written to read O2 sensor input? For example 17.0 to 1 air fuel is so many ohms which will require a subtraction of so much fuel. Is this possible?
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2000redrocket
Pro
Posts: 1662
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posted September 22, 2009 08:01 PM
this is a question for RR. i think with all the things going on with air temp ,density,load,throttle position,engine temp, timing . etc it would be hard to run one live off the o2 sensor. it as with a car could be done i bet cruising around but one like us who got the bike modded and wants the afr perfect all the time to keep it safe will not cruise much i bet though to race my bike at the grove i run it 1 hour each way. just getting the density map correctly tuned is going to be load sensitive and should be as set all the time..
air temp wise i am not sure how it is inputed. i think it changes restance with temp like the collant sensor. it probaly pulls to ground and the ecu mesures restance or vdc.
supra look into the motts afr tuner
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