Power Vision Information Thread
Outstanding HDF Member
Joined: Jun 2014
Posts: 3,185
Likes: 189
From: 90210
[QUOTE=usaf8ret;14881007]
Yes that is part of it, but fuel is also a part of the equation. but like I said, go out and research the details. lots of info resources online that discuss engine Volumetric Efficiency and Delphi EFI in very complete detail. It's a bit OT to continue in more detail here.
To put it very simply, the Main VE table is fueling at different engine loads vs. rpms. The VE table kpa is the measurement of air pressure to help determine the load on the engine or Manifold Absolute Pressure (MAP)
What? Are you sure the Main VE table isn't a number that reflects airflow through the engine?
What? Are you sure the Main VE table isn't a number that reflects airflow through the engine?
Advanced
Joined: Feb 2016
Posts: 71
Likes: 0
From: USA
[QUOTE=LA_Dog;14881046]
Yes that is part of it, but fuel is also a part of the equation. but like I said, go out and research the details. lots of info resources online that discuss engine Volumetric Efficiency and Delphi EFI in very complete detail. It's a bit OT to continue in more detail here.
I don't think you have a clear idea of what's happening with the VE's, what they represent, how they affect target AFR's, and how the closed loop system uses them to reach a target AFR. How many bikes have you tuned? Think about it for a minute. I install a stage 1 air filter and exhaust. What happens? Airflow through the engine increases, right. So what do I need to do? I need to reflect that increase in airflow via a VE number to achieve a target AFR. Doesn't the system need to know how much AIR is flowing through system? Doesn't it then add a certain amount of fuel to avhieve whatever my desired target AFR is? Every book I've read tells me that VE's are a representation of AIRFLOW through the engine. Fueling, as you put it, happens afterwards.
Yes that is part of it, but fuel is also a part of the equation. but like I said, go out and research the details. lots of info resources online that discuss engine Volumetric Efficiency and Delphi EFI in very complete detail. It's a bit OT to continue in more detail here.
Road Master
Joined: Feb 2014
Posts: 804
Likes: 237
From: TN
Going to add a little here. There really isn't a closed loop. Its a nickname given to the range of narrow band sensors. Lambda .977 to 1.0 or 14.34 to 14.68 afr, are the sensor's range. Maybe a little more. Wide band sensors will cover a larger range, and work just fine. Narrow band sensors were adapted to keep the EPA happy. So really anything with sensors could be considered "closed loop" from the carb days, lol! As far as ve goes I think it has to do more with cylinder fill. Yes there is more air flowing through the motor, but there is no real way for the system to measure it. There are sensors, how accurate they are is up for debate. It is an estimate based on what the engineers have programmed in. So when you change the charge dilution tables the ve tables change without ever changing the flow characteristics of the engine. it all calculations / math formulas.
Intermediate
Joined: Mar 2014
Posts: 30
Likes: 0
From: WA
Going to add a little here. There really isn't a closed loop. Its a nickname given to the range of narrow band sensors. Lambda .977 to 1.0 or 14.34 to 14.68 afr, are the sensor's range. Maybe a little more. Wide band sensors will cover a larger range, and work just fine. Narrow band sensors were adapted to keep the EPA happy. So really anything with sensors could be considered "closed loop" from the carb days, lol! As far as ve goes I think it has to do more with cylinder fill. Yes there is more air flowing through the motor, but there is no real way for the system to measure it. There are sensors, how accurate they are is up for debate. It is an estimate based on what the engineers have programmed in. So when you change the charge dilution tables the ve tables change without ever changing the flow characteristics of the engine. it all calculations / math formulas.
Volumetric efficiency is the percentage of actual cylinder volume that the engine can fill the cylinder at particular RPM/MAP or TPS. Auto tune calculates the VE. Pretty sure it backs it out of the fueling equation (uses the same equation, but solves for VE instead of injector pulse). So or VEs after auto tune are calculated. The VE table gets used to calculate the fueling requirements along with other input, like IAT, MAP, ET, and a bunch of other stuff I'm sure.
The CDE is supposed to be the percentage of pressure (MAP), that isn't from fresh air, but due to burnt gases getting into the intake tract (can overlap), but without really knowing how much it really is, we can use it to flatten our VE maps to lessen the differences between cells, so interpolations are more accurate to the actual need. It changes the culling calc, and if auto tuned after changing CDE it will change the VE tables.
Don't ask me how to do that, I'm still learning myself. I'm not a professional tuner (but have been a mechanical engineer for nearly 30 years, and a gear head for nearly 40. I just know enough to make myself a danger).
Road Master
Joined: Mar 2007
Posts: 1,177
Likes: 23
I like to think of VE as the last big fudge factor to get the AFR to hit the Target AFR. "Closed loop" is a constantly changing fudge factor to the VE to help the motor better stay on target.
We can get more technical if you guys really want. Here is something I wrote to help people get their head around basic EFI tuning.
http://www.nbs-stl.com/tuning/BasicTuning101.pdf
Andy
We can get more technical if you guys really want. Here is something I wrote to help people get their head around basic EFI tuning.
http://www.nbs-stl.com/tuning/BasicTuning101.pdf
Andy
Outstanding HDF Member
Joined: Jun 2014
Posts: 3,185
Likes: 189
From: 90210
I like to think of VE as the last big fudge factor to get the AFR to hit the Target AFR. "Closed loop" is a constantly changing fudge factor to the VE to help the motor better stay on target.
We can get more technical if you guys really want. Here is something I wrote to help people get their head around basic EFI tuning.
http://www.nbs-stl.com/tuning/BasicTuning101.pdf
Andy
We can get more technical if you guys really want. Here is something I wrote to help people get their head around basic EFI tuning.
http://www.nbs-stl.com/tuning/BasicTuning101.pdf
Andy
Outstanding HDF Member
Joined: Jun 2014
Posts: 3,185
Likes: 189
From: 90210
[QUOTE=usaf8ret;14881104]
I don't think you have a clear idea of what's happening with the VE's, what they represent, how they affect target AFR's, and how the closed loop system uses them to reach a target AFR. How many bikes have you tuned? Think about it for a minute. I install a stage 1 air filter and exhaust. What happens? Airflow through the engine increases, right. So what do I need to do? I need to reflect that increase in airflow via a VE number to achieve a target AFR. Doesn't the system need to know how much AIR is flowing through system? Doesn't it then add a certain amount of fuel to avhieve whatever my desired target AFR is? Every book I've read tells me that VE's are a representation of AIRFLOW through the engine. Fueling, as you put it, happens afterwards.
Respectfully, I think you have a handle on only a very narrow slice of the overall tuning picture and what the VE tables represent in the tune as a whole. You're not incorrect, but you're not completely correct either. Start with Andy's pdf above and have a run through it. All of this will make more sense once you grasp how the EFI components, tables, etc relate to each other in the tune.
This is also a very decent guide and read on the entire HD Delphi system and each of the components: http://files.meetup.com/19315510/EFI%20Basics.pdf
I don't think you have a clear idea of what's happening with the VE's, what they represent, how they affect target AFR's, and how the closed loop system uses them to reach a target AFR. How many bikes have you tuned? Think about it for a minute. I install a stage 1 air filter and exhaust. What happens? Airflow through the engine increases, right. So what do I need to do? I need to reflect that increase in airflow via a VE number to achieve a target AFR. Doesn't the system need to know how much AIR is flowing through system? Doesn't it then add a certain amount of fuel to avhieve whatever my desired target AFR is? Every book I've read tells me that VE's are a representation of AIRFLOW through the engine. Fueling, as you put it, happens afterwards.
This is also a very decent guide and read on the entire HD Delphi system and each of the components: http://files.meetup.com/19315510/EFI%20Basics.pdf
Last edited by LA_Dog; Feb 26, 2016 at 07:56 PM.
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
7 Times Harley-Davidson Chucked Tradition Out the Window
Verdad Gallardo
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
Outstanding HDF Member
Joined: Jun 2014
Posts: 3,185
Likes: 189
From: 90210
Thanks Andy- you are one of the few treasure troves of tuning info out there. just a thought, if you put an index directory up with everything under one parent folder, and grant read access + directory browsing to that folder path, then anyone can browse the entire file collection including sub folders under it. something like nbs-stl.com/tuningstuff/
Road Master
Joined: Mar 2007
Posts: 1,177
Likes: 23
Funny that Harley used an old version of Megasquirt / Tuner Studio to generate some of the screen shots in their Bosch document. Go figure...
LA Dog, have you seen http://www.nbs-stl.com/tuning/
Andy
LA Dog, have you seen http://www.nbs-stl.com/tuning/
Andy