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nyet
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« Reply #120 on: July 03, 2014, 03:35:31 PM »
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However, I'm not sure what you mean that I should not be moving. There is boost error present so I needs to be moving to correct it.
Just saying that if DRL is calibrated correctly, a constant boost req should not require the PID to do anything (or much)... pre->post lin correction should be sufficient to (mostly) maintain boost, and lde should remain near zero. |
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phila_dot
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« Reply #121 on: July 03, 2014, 05:04:18 PM »
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Just saying that if DRL is calibrated correctly, a constant boost req should not require the PID to do anything (or much)... pre->post lin correction should be sufficient to (mostly) maintain boost, and lde should remain near zero.
Conpletely accurate, but that's also assuming P, I, and D are doing their job. I should still track back to the setpoint in steady state if it needs to. I get what you're saying though that I shouldn't have to do much after it accumulates. |
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nyet
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« Reply #122 on: July 03, 2014, 05:21:17 PM »
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Conpletely accurate, but that's also assuming P, I, and D are doing their job. I should still track back to the setpoint in steady state if it needs to.
Yep. But remember, P is out of the gain schedule if lde is anywhere remotely near zero. And D should be basically zero, since nothing should be moving if req boost is steady and DRL is calibrated correctly. |
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phila_dot
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« Reply #123 on: July 03, 2014, 05:54:40 PM »
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Yep. But remember, P is out of the gain schedule if lde is anywhere remotely near zero. And D should be basically zero, since nothing should be moving if req boost is steady and DRL is calibrated correctly.
Did you mean D is zero in steady state and P is near zero based on current error? |
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nyet
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« Reply #124 on: July 03, 2014, 10:13:47 PM »
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Did you mean D is zero in steady state and P is near zero based on current error?
Yes and yes. And when P is near zero, it is out of the gain sched.. |
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Basano
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« Reply #125 on: July 04, 2014, 12:47:27 AM »
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Hi! Interesting comments, borne out by what I saw in the logs. D is zero in the steady state. I increased KFLDRL and logged again this morning. A bit surprised by the result... As far as I can make out, the post-linearization duty cycle remains the same, but less pre-linearization duty cycle is needed to achieve this. And the boost curve stays the same. It's like the actual boost is has reached some other set point and the PID is maintaining it. Love to hear what you make of this   There are two plot's overlaid in the chart, before and after the KFLDRL changes. Purple line is pre-lin duty cycle (ldtvr_w) Green line is post-lin duty cycle (ldtvm or ldtv_w, they are the same in value) Red line is specified boost Blue line is actual boost |
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« Last Edit: July 04, 2014, 12:50:22 AM by Basano »
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Nottingham
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« Reply #126 on: July 04, 2014, 04:43:59 AM »
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Could someone help me on the rev & speed limiters on the attached (stock) file?
For some reason changing the NMAX (1C9982h), NMAXGA (1DB368h) and NMAXOGGA (1DB380h) have no effect what so ever.
The engine still cuts at the stock limit (6800rpm). The GA and OGGA tables shouldn't be even altered but I tried that too just to be sure.
Also all of the VMAX related limiters seem to be set either to 255km/h or 511km/h but yet the actual VMAX seems to be limited to around 230km/h.
At that speed the engine starts cutting power.
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IamwhoIam
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« Reply #127 on: July 04, 2014, 06:14:12 AM »
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You need to open your eyes a bit more for Nmax  it's VERY easy. |
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I have no logs because I have a boost gauge (makes things easier)
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nyet
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« Reply #128 on: July 04, 2014, 09:47:04 AM »
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As far as I can make out, the post-linearization duty cycle remains the same, but less pre-linearization duty cycle is needed to achieve this. And the boost curve stays the same.
Keep going! Add more DRL until the pre-lin is flat where req boost is flat. Near steady state, the shape of pre-lin should roughly match req boost. I'm guessing you're near the turbo's limit, which means no matter how much DRL you add, you may never see req boost. At that operating point, boost is likely almost unresponsive to DC. |
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Nottingham
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« Reply #129 on: July 04, 2014, 12:43:23 PM »
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You need to open your eyes a bit more for Nmax it's VERY easy. Forgot to say that I already adjusted NMAXDV and NMAXDZ too, zero effect. Unless the rpm limit set by NMAXTO is active even below the lowest oil temperature I am pretty much out of ideas  There's NMAXDVG too I see. |
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Basano
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« Reply #130 on: July 04, 2014, 01:52:23 PM »
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Behold, the masterpiece... Well not quite, but I have an answer! I'm guessing you're near the turbo's limit, which means no matter how much DRL you add, you may never see req boost. At that operating point, boost is likely almost unresponsive to DC.
Spot on. I've just logged one more iteration of KFLDRL where I jump straight to 95%. No half-measures, just 95% output for any input greater than 20% from 5500 rpm upwards. And yes, actual boost still tails off. Why am I so pleased? - because now I understand I've run into a physical limitation of my KO4! I'll work on tidying up KFLDRL  |
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« Last Edit: July 04, 2014, 01:55:33 PM by Basano »
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majorahole
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« Reply #131 on: July 04, 2014, 02:10:43 PM »
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Forgot to say that I already adjusted NMAXDV and NMAXDZ too, zero effect. Unless the rpm limit set by NMAXTO is active even below the lowest oil temperature I am pretty much out of ideas There's NMAXDVG too I see. could something else be causing the issue? aren't those limiters "without errors"?? I'm just guessing as I haven't even bothered raising those as my engine didn't seem to make anymore power past 6200rpm as it is |
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Nottingham
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« Reply #132 on: July 04, 2014, 02:24:59 PM »
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Regarding the VMAX I'm no longer sure what to believe.
ECUSafe shows that one of the several VMAX limiters is set to 225km/h, which is within the range of the actual top speed achieavable.
This 225km/h limiter (7080h) however is defined as NMAXF, which equals 7200rpm with the 0.25 factor. With the factor used for VMAX (1/128, 0.007813) the value
is 225km/h. I assume the same value cannot have two different meanings?
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nyet
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« Reply #133 on: July 04, 2014, 05:42:53 PM »
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And yes, actual boost still tails off. Why am I so pleased? - because now I understand I've run into a physical limitation of my KO4!
which probably means you are probably way off the reservation efficiency wise, and likely near the overspin boundary. Consider consulting the K04 compressor map... |
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Nottingham
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« Reply #134 on: July 05, 2014, 03:29:35 PM »
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Regarding the fuelling, please correct me if I am wrong:
The stock injectors on 200hp (e.g. AXX & BWA) engines seem to flow 1027cm³/min @ 110bar based on the KRKATE (34.25 / 0.03333).
When I swapped the S3 injectors I used the flow difference of 13% stated by APR as a ballpark value.
Based on the logs I made the actual difference in the flow is pretty exactly 15%. With KRKATE scaled down by 13% the LTFT has settled to -2%.
However if I raise the fuel pressure for example from 110bar to 120bar the KRKATE needs to be scaled again?
(1027 * 1.15) * ((120/110) SQRT) = ~ 1233cm³/min <> (34.25 / 1233) = 0.02777ms (KRKATE)
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