Auto Tune, how does it work ?
Extreme HDF Member
Joined: Aug 2013
Posts: 16,271
Likes: 15,108
From: Somewhere SW
That's auto tune basic using the factory narrow band 02 sensors.
There are other auto tuning setups out there that use broad band 02 sensors that have to be installed on the bike.
Target Tune being the most recent one on the market.
http://www.dynojet.com/powervision/p...rget-tune.aspx
You never mentioned which tuner you have.
Road Master
Joined: Mar 2007
Posts: 1,177
Likes: 23
Here is a plot that we can all use to help explain autotuning in the Harley world. You have to keep in mind that NB O2 sensors are only good at finding 14.7 AFR (for some reason the Harley world uses the number 14.6) Either way they mean Stoich. Or right at the edge of there is still some O2 in the exhaust or there is no O2 left.
http://www.nbs-stl.com/HarleyTuning/...ed%20Views.png
On the left of this screen shot is a scatter plot showing the O2 voltage with most of the samples are either shown as near .2 volts or on the lean side of 14.7 AFR. There is also many red dots indicating near .8 volts or richer than 14.7 AFR.
Keep in mind that this motor is running most everywhere in open loop. The ECU in this example is only logging the RPM, MAP and O2 voltage.
On the right is the same data rolled up into RPM by MAP boxes. Blue areas indicate lean averages. Pinkish boxes indicate the the AFR averaged rich.
Boxes that averaged real close to 14.7 AFR show up as green or have an average voltage of real close to 14.7 AFR or real close to .5 volts average.
We will talk about the larger colored boxes a bit later....
Any questions so far?
Andy
http://www.nbs-stl.com/HarleyTuning/...ed%20Views.png
On the left of this screen shot is a scatter plot showing the O2 voltage with most of the samples are either shown as near .2 volts or on the lean side of 14.7 AFR. There is also many red dots indicating near .8 volts or richer than 14.7 AFR.
Keep in mind that this motor is running most everywhere in open loop. The ECU in this example is only logging the RPM, MAP and O2 voltage.
On the right is the same data rolled up into RPM by MAP boxes. Blue areas indicate lean averages. Pinkish boxes indicate the the AFR averaged rich.
Boxes that averaged real close to 14.7 AFR show up as green or have an average voltage of real close to 14.7 AFR or real close to .5 volts average.
We will talk about the larger colored boxes a bit later....
Any questions so far?
Andy
Road Master
Joined: Mar 2007
Posts: 1,177
Likes: 23
In simple terms, what an autotune does is locate areas that are clearly blue and add some fuel in those areas. It also looks for the areas that are clearly red and pull a little fuel from that area.
Then we retest.....
Andy
Then we retest.....
Andy
Extreme HDF Member
Joined: Aug 2013
Posts: 16,271
Likes: 15,108
From: Somewhere SW
What software are you using?
Road Master
Joined: Mar 2007
Posts: 1,177
Likes: 23
HEHE
Right now I am messing with Target Tune. Generally, I start by using the Autotune software as intended by the manufacturer. I then use MegaLogViewer HD to verify that the Autotune SW is working as advertised. If I like the SW I like to help other people learn to use the SW. If it does not work as advertised, I get back to the manufacturer as to what is not working as advertised.
I tend to hand tune all tunes once I identify the limits of the system. All hand tuning is done based on what I learn from MLV HD.
All autotune systems generally work on the same tuning principals. Adjust the VEs to hit the target AFRs.
Andy
Right now I am messing with Target Tune. Generally, I start by using the Autotune software as intended by the manufacturer. I then use MegaLogViewer HD to verify that the Autotune SW is working as advertised. If I like the SW I like to help other people learn to use the SW. If it does not work as advertised, I get back to the manufacturer as to what is not working as advertised.
I tend to hand tune all tunes once I identify the limits of the system. All hand tuning is done based on what I learn from MLV HD.
All autotune systems generally work on the same tuning principals. Adjust the VEs to hit the target AFRs.
Andy
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Verdad Gallardo
8 Best Harley-Davidson Motorcycles Ever
Pouria Savadkouei
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
10 Motorcycles You Should Never Buy
Joe Kucinski
10 Things Harley-Davidson Needs to Fix in 2026
Verdad Gallardo
Thread Starter
|
Cruiser
Joined: Aug 2015
Posts: 113
Likes: 4
From: Dartmouth, Devon, UK
I'm not talking about any specific tuner and the use of factory o2 sensors. Perhaps it would help if I show my original question.
Auto Tune, how does it work ?
OK, so we all believe Harley tune on the lean side. So you get a tuner and on a simple Stage 1 the AFR tables are richer. Job done, or is it ?
So Auto Tune :
What does it do ?
What does it alter ?
How/what does it sense/detect, so that it makes the changes ?
In other words, if at a point the AFR was 14.6 and the new map is 14.3, doesn't that tell the ECU what to do ?
What is the Auto Tuner actually doing then ? Is it altering the map ? If so on what sensed information ? and why ?
I'm looking for a detailed explanation please ?
Thanks
Dave
OK, so we all believe Harley tune on the lean side. So you get a tuner and on a simple Stage 1 the AFR tables are richer. Job done, or is it ?
So Auto Tune :
What does it do ?
What does it alter ?
How/what does it sense/detect, so that it makes the changes ?
In other words, if at a point the AFR was 14.6 and the new map is 14.3, doesn't that tell the ECU what to do ?
What is the Auto Tuner actually doing then ? Is it altering the map ? If so on what sensed information ? and why ?
I'm looking for a detailed explanation please ?
Thanks
Dave
Road Master
Joined: Mar 2007
Posts: 1,177
Likes: 23
Dave
Here is the basic fuel equation that all (non MAF) EFI systems use.
http://www.nbs-stl.com/MLVDemo/012%2...ngEquation.PNG
In the PowerVision/Harley world, we are talking about the Long Term Fuel Trim called AFF and the Short Term Fuel Trim called CLI.
Note that some terms drop to 1, depending on how the Cal is set up.
Andy
Here is the basic fuel equation that all (non MAF) EFI systems use.
http://www.nbs-stl.com/MLVDemo/012%2...ngEquation.PNG
In the PowerVision/Harley world, we are talking about the Long Term Fuel Trim called AFF and the Short Term Fuel Trim called CLI.
Note that some terms drop to 1, depending on how the Cal is set up.
Andy
Last edited by whittlebeast; Nov 28, 2015 at 12:36 PM.