Lean burn with negative split timing
05-18-2011, 10:38 PM
#76
I have not played with these particular maps as much as you have but from what I did do i concluded that the C/L fuel maps were a modifier to the main map - not an actual target .
The ECU wants to see 14.7 so sets a LTFT till that is achieved .
My wideband AFR gauge is out by a little but it picks up any change 'on the fly' . BTW the 2005 software I have allows you to go to 2.0 (up from 1.0).
The ECU wants to see 14.7 so sets a LTFT till that is achieved .
My wideband AFR gauge is out by a little but it picks up any change 'on the fly' . BTW the 2005 software I have allows you to go to 2.0 (up from 1.0).
05-18-2011, 11:01 PM
#77
Closed loop targets A, is referenced to the main maps, but it is like a divisor.
Main map target = 1.0
Closed loop A = 0.95
Fuel target = 1.0/.95 = 1.05 lambda or ~15.5:1 AFR
Many of these tables are counter-intuitive, unless you have a mind like an embedded CPU with limited memory.
Like I said "targets B" is more for helping the closed loop reach its target. For example, if you changed fuel injectors and at a steady state the STFTs were jumping back and forth from positive to negative, you might want less gain.
However, if it was taking a long time to reach the target AFR at a steady state, you might want more gain.
I'm mostly just guessing though.
Main map target = 1.0
Closed loop A = 0.95
Fuel target = 1.0/.95 = 1.05 lambda or ~15.5:1 AFR
Many of these tables are counter-intuitive, unless you have a mind like an embedded CPU with limited memory.
Like I said "targets B" is more for helping the closed loop reach its target. For example, if you changed fuel injectors and at a steady state the STFTs were jumping back and forth from positive to negative, you might want less gain.
However, if it was taking a long time to reach the target AFR at a steady state, you might want more gain.
I'm mostly just guessing though.
05-18-2011, 11:09 PM
#78
Closed loop targets A, is referenced to the main maps, but it is like a divisor.
Main map target = 1.0
Closed loop A = 0.95
Fuel target = 1.0/.95 = 1.05 lambda or ~15.5:1 AFR
Many of these tables are counter-intuitive, unless you have a mind like an embedded CPU with limited memory.
Like I said "targets B" is more for helping the closed loop reach its target. For example, if you changed fuel injectors and at a steady state the STFTs were jumping back and forth from positive to negative, you might want less gain.
However, if it was taking a long time to reach the target AFR at a steady state, you might want more gain.
I'm mostly just guessing though.
Main map target = 1.0
Closed loop A = 0.95
Fuel target = 1.0/.95 = 1.05 lambda or ~15.5:1 AFR
Many of these tables are counter-intuitive, unless you have a mind like an embedded CPU with limited memory.
Like I said "targets B" is more for helping the closed loop reach its target. For example, if you changed fuel injectors and at a steady state the STFTs were jumping back and forth from positive to negative, you might want less gain.
However, if it was taking a long time to reach the target AFR at a steady state, you might want more gain.
I'm mostly just guessing though.
I thought 'B' might just be 4-6 th gear with 'A' being 1-3 . But i have not tried testing that . The changes i made were identical on both maps .
How you can say the changes stick - without actually monitoring the AFR confuses me .
I can show you a log where the LTFT changes in mid stream to correct the lean mix.
Last edited by Brettus; 05-18-2011 at 11:12 PM.
05-18-2011, 11:38 PM
#82
05-18-2011, 11:39 PM
#83
And open loop is the same thing as CL? 
It is not a secret. It just isn't something that he (or I) can just "tell" you.
I doubt Team would feel particularly motivated to sit here and educate you on the subject.
I know I'm not. It is difficult and annoying to type all that stuff out, just to have it misunderstood and applied out-of-context.
I doubt Team would feel particularly motivated to sit here and educate you on the subject.
I know I'm not. It is difficult and annoying to type all that stuff out, just to have it misunderstood and applied out-of-context.
Last edited by MazdaManiac; 05-18-2011 at 11:41 PM.
05-18-2011, 11:48 PM
#85
And open loop is the same thing as CL?
It is not a secret. It just isn't something that he (or I) can just "tell" you.
I doubt Team would feel particularly motivated to sit here and educate you on the subject.
I know I'm not. It is difficult and annoying to type all that stuff out, just to have it misunderstood and applied out-of-context.
It is not a secret. It just isn't something that he (or I) can just "tell" you.
I doubt Team would feel particularly motivated to sit here and educate you on the subject.
I know I'm not. It is difficult and annoying to type all that stuff out, just to have it misunderstood and applied out-of-context.
05-18-2011, 11:52 PM
#86
If you want to tell me something, go ahead. Otherwise I'll move on to flash #138 (seriously.)
I really don't understand the purpose of telling me you know something, and then not telling me what. Just trying to be annoying?
Also, I'm sure the webinar is completely worth it. I have no problem paying for knowledge. Indeed, that is the whole problem. I'll take the webinar if it is still available when I've paid my student loans.
I really don't understand the purpose of telling me you know something, and then not telling me what. Just trying to be annoying?
Also, I'm sure the webinar is completely worth it. I have no problem paying for knowledge. Indeed, that is the whole problem. I'll take the webinar if it is still available when I've paid my student loans.
Last edited by oltmann; 05-19-2011 at 12:06 AM.
05-18-2011, 11:52 PM
#87
you can pay the price of entry the same as anyone else
05-19-2011, 12:05 AM
#88
because as usual people misjudge me, while in this particular case I paid for the knowledge the reason I am privvy to a lot of great information is because I don't undermine the efforts of the people who share it with me, homey don't play that way ....
you can pay the price of entry the same as anyone else
you can pay the price of entry the same as anyone else
05-19-2011, 09:13 AM
#90
It occurs to me that Mazda might be working on lean burn just for emissions reasons. All emissions drop when you go really lean, add a two-way cat and a NOx trap and you make the EPA happy. Might be a needed change to keep rotaries viable regardless of whether lean burn gives rotaries the same fuel economy gains as piston engines.
I think both this HCCI thing and what's described of the Skyactiv-G engines are different ways to get into a lean burn mode. Using either HCCI or Miller-cycle is a way to drop combustion temps and thus NOx production. Without NOx to worry about, one can then freely go into the high afr's for better mpgs. One thing's for sure though, the next-gen engine management systems are gonna make the present ones look as primitive DOS does now.
Dunno what overlap if any there is with Skyactiv-R.
05-19-2011, 11:25 AM
#91
Mazda already got their *** handed to them, thanks to Miller Cycle. I doubt they are in a rush to repeat the experience.
Actually, the current engine management systems are operating at a fraction of their capacity, which is already WAY beyond the duty cycle of a gasoline engine.
There will just be more tables.
If you want to get a kick sometime, look at how many tables the Speed3 has compared to the RX-8. It is more than double.
There will just be more tables.
If you want to get a kick sometime, look at how many tables the Speed3 has compared to the RX-8. It is more than double.
05-19-2011, 11:51 AM
#92
Mazda already got their *** handed to them, thanks to Miller Cycle. I doubt they are in a rush to repeat the experience.
Actually, the current engine management systems are operating at a fraction of their capacity, which is already WAY beyond the duty cycle of a gasoline engine.
There will just be more tables.
If you want to get a kick sometime, look at how many tables the Speed3 has compared to the RX-8. It is more than double.
Actually, the current engine management systems are operating at a fraction of their capacity, which is already WAY beyond the duty cycle of a gasoline engine.
There will just be more tables.
If you want to get a kick sometime, look at how many tables the Speed3 has compared to the RX-8. It is more than double.
"Mazda's first dual sequential valve timing system (dual S-VT with electronically-operated intake) in combination with the high compression ratio achieves an unconventional Miller cycle (extremely delayed closure of intake valves) that improves efficiency" from http://www.mazda.com/publicity/relea...5/110518a.html
Clock cycles, yeah, aren't gonna change, but complexity will as there become more parameters to adjust and the engines start running closer to the edge of destruction. (14:1 compression, lean, etc). One would also expect replacement of conventional throttle plate control by pedal with having the accelerator pedal command a torque or power and the ECU adjust everything, including the throttle plate, in response.
05-19-2011, 12:50 PM
#93
"Mazda's first dual sequential valve timing system (dual S-VT with electronically-operated intake) in combination with the high compression ratio achieves an unconventional Miller cycle (extremely delayed closure of intake valves) that improves efficiency" from http://www.mazda.com/publicity/relea...5/110518a.html
They already do that with the Speed3 and Speed6.
05-19-2011, 01:21 PM
#95
I realize this thread is a bit of an intellectual exercise and that there are no "absolute" AFRs - the engine needs what it needs - but the best torque fuel values are pretty well known on the Renesis for all operating loads and RPMs.
Operating the engine at values that deviate from the known values does NOT increase fuel efficiency because maximum torque IS maximum efficiency.
05-19-2011, 01:57 PM
#97
Administrator
what they are using is the stroke of a miller cycle and using 14:1 compression instead of a SC. its simply a means for them to help explain what they are doing. what they have done really is create a Spark ignited HCCI engine.
05-20-2011, 09:47 AM
#100
I suppose one could apply this to a wankel rotary by adding a variable "leak" at the beginning of the compression stroke. Seems to me though this would negate an undeniable advantage of the rotary: high power output / total engine volume.
