 |
|
|
1999-2009 [Subscribe to Daily Digest] |
 | [Main 95 Bulletin Board | BBFAQ |
Prev by Date | Post Followup ]
Member Login / Signup - Members see fewer ads. - Latest Member Gallery Photos
Yet One More Take on adaptation Posted by Ari [Email]  (#2847) [Profile/Gallery]
(more from Ari) on Tue, 28 Sep 2004 10:26:16
In Reply to: Re: T7 learns......, technologist, Mon, 27 Sep 2004 20:31:20 Members do not see ads below this line. - Help Keep This Site Online - Signup |
There is no advantage in having the car produce less power for someone that drives the car less agressively. I don't believe that's how the adaptation works.
With the pre T-7 system, the Trionic control performed 'adaptation.' The job of the engine control is to provide the appropriate amount of fuel for the engine speed and mass of air coming in. To do this, the engine control has a look-up table, where it takes engine RPM and a calculated air mass, and determines how long to open up the injectors. There is also adjustment around the O2 sensor, but in cases where the engine is accelerating/decelerating, the control needs a way to set the fuel flow as conditions are changing. All well and good, but that map is for a 'typical' engine, and every engine is different. So the system performs 'adaptation', where it sees how far off the fuel map was for a given engine speed/air mass, under controlled situation (sustained acceleration, for example). It then 'adjusts' the map by writing a correction factor for that speed/air combo to memory. The next time the engine gets to that point, the 'improved' value is used.
This allows you to get the best performance. You can force the engine to do an adaptation by resetting the memory (disconnecting the battery) and then performing an adaptation run, which is simply getting the engine to accelerate a full throttle for a long enough duration for the adaptation to kick in. If the criteria for adaptation aren't met (speed change over X seconds, RPM range, etc), it doesn't adapt.
Engines change with time, fuel changes with season, etc. So over time those adaptation points aren't quite as valid as they used to be. If you've been driving the car leisurely, The full-throttle adaptation won't happen, and the engine won't produce as much power. That's not because the control won't give you the power as a punishment for not driving hard. It's because the fuel maps are a bit 'stale', and haven't kept up with changes in the engine.
Again, adaptation only occurs if you keep up sustained boost over a certain RPM range, and for a certain time. Little stabs of power won't do it.
This is entirely different than transmissions, where a different 'learning' comes into play. Some trannies 'learn' from a driver in that if they like to do lots of hard acceleration, the shift points move higher. This provides better acceleration but with added harshness and noise. If you drive the car leisurely, it drops the shift points, which gives a smoother ride, but with less performance.
posted by 192.249....
, Mon, 27 Sep 2004 14:28:39, Tue, 28 Sep 2004 10:26:16 <-- Viewing This Message
No Site Registration is Required to Post - Site Membership is optional (Member Features List), but helps to keep the site online
for all Saabers. If the site helps you, please consider helping the site by becoming a member.
 |
 |
 |
 |
 |
