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I have read repeatedly about the Prius' ability to learn the driving style of its operator. I can attest to this, but only in a vague form. I am trying to figure out exactly what the car does in the learning process.

What activities does it monitor?
What behavior does it adjust in response?

I would also be interested in any technical articles on the subject, as I am a nerd at heart.

Jay
 

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The only learning I know of is the type that most OBD-II controleld cars do, which is to recalibrate the factors that modify the air-fuel ratio during warmup, acceleration, high and low temps. Despite the closed nature of the new EFI/O2 sensor systems, there is still a lot of unpredicatable behavior during transitions to/from vrious load/temperature states. It also can accomodate the aging of the car as compression is lowered and other changes happen to the engine systems. Such recalibrations are lsot when the memory is erased, and the learning must happen again. I believe this accounts for much of the MPG drop noted when cars are taken into the shop for seemingly unrelated repairs.
 

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MY Ford F-150 Service manuals do a better job with this topic than the Toyota Prius manuals.

The o2 sensors read 'after the burn' and make corrections as needed.
The OBDII computer "remembers" the last best settings from pervious driving condiions and starts out using these settings and the o2 sensors then adjust from there. ( in my own words ). The computer has short term look up tables with these settings 'learned'. Neat suff. The long term tables are for aging components. When we get a sudden change in seasons, I will get error code usually a misfire - caused by the engine using a setting that no longer works for the new outside temptures. The error code cleans itself out in a few drive cycles.

Remove the battery lead and all setting are forgotten and the engine will run a little ruff until the settings can be relearned.

Hope this helps.
 
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