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Author Topic: Ignition cut rev limiter me7  (Read 14304 times)
adam-
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« Reply #60 on: July 24, 2017, 03:58:01 AM »

You want to cut spark before you cut fuel.

Lift your NMAX.

Read the maps you're editing and don't just throw numbers in because someone else did the same thing.  Try and understand what you're attempting to do.

You've lifted error detection to 7500 for no reason.
« Last Edit: July 24, 2017, 04:00:31 AM by adam- » Logged

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cpp
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« Reply #61 on: July 25, 2017, 09:17:26 AM »

I raised nmaxf 400 rpm to more than nmax. It was the difference between nmax 6800 and nmaxf 7100. I did it because in the original bin it was at 7100 which would be my new nmax. So I added another 400 rpm to nmaxf.
I have 7100 rpm in the soft limiter. I wanted to have that same 7100 rpm with hard limiter.
I did a nmax test at 7300 rpm. More so cut at 5800 rpm.

Thank you for the tip
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Gaghunfv2
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« Reply #62 on: August 08, 2017, 09:04:36 AM »

Sorry for my dumb questions, I never did a ignition cut rev limiter.
Wouldn't it be enough if I just set NMAX higher than NMAXOG like in the screenshot?

What is KFTSRL?
What is KFSZT?

KFSZT is in association with the battery voltage.
Why do I need to change a map which contains the battery voltage? Isn't this unnecessary for a rev limiter?  Huh
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nyet
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« Reply #63 on: August 08, 2017, 08:35:13 PM »


Why do I need to change a map which contains the battery voltage? Isn't this unnecessary for a rev limiter?  Huh


Read the FR.
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Gaghunfv2
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« Reply #64 on: August 09, 2017, 01:00:38 AM »


Read the FR.

I've read it the 3rd time now, I still don't understand why I need to change this two maps.
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nyet
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« Reply #65 on: August 09, 2017, 10:49:48 AM »

NMAX is the soft limiter (fuel cut).
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ME7.1 tuning guide (READ FIRST)
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Please do not ask me for tunes. I'm here to help people make their own.

Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your experience.
Gaghunfv2
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« Reply #66 on: August 10, 2017, 01:05:35 AM »

Thanks  Smiley
So NMAX and NMAXOG are just fuel cut.
That means, that KFTSRL and KFSZT are involved in ignition cut?
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adam-
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« Reply #67 on: August 10, 2017, 04:17:03 AM »

The concept is entirely based around that.  Cut spark before fuel. 
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Gaghunfv2
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« Reply #68 on: August 10, 2017, 04:32:44 AM »

I understand the concept, it's kind of easy.
My problem is just knowing what the maps are doing. I could just copy your changes, adam, but I want to learn how to do it by myself.
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nyet
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« Reply #69 on: August 10, 2017, 12:15:23 PM »

That means, that KFTSRL and KFSZT are involved in ignition cut?

No, it depends on the ECU.

Not sure how you got this far without reading this:

http://nefariousmotorsports.com/forum/index.php?topic=11664.msg97574#msg97574

and this:

http://nefariousmotorsports.com/forum/index.php?topic=445.45
« Last Edit: August 10, 2017, 12:18:39 PM by nyet » Logged

ME7.1 tuning guide (READ FIRST)
ECUx Plot
ME7Sum checksum checker/corrrector for ME7.x

Please do not ask me for tunes. I'm here to help people make their own.

Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your experience.
Gaghunfv2
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« Reply #70 on: August 11, 2017, 03:10:49 AM »

Not sure how you got this far without reading this:
No need to be rude  Sad
"Please do not ask me for tunes. I'm here to help people make their own."

Again: I read the whole thread a few times.
But nowhere is an explanation of what this two maps are doing and what "closing time" is. This thread instantly began with map ID's I never edited.
I just did some basic remaps on 1.8T's and 1.9TDI's.

-I used google to search for an explanation
-I've read and searched through the s4wiki
-I used the search-function in this forum
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RBPE
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« Reply #71 on: August 11, 2017, 07:27:30 AM »

ZUESZ in the Function Sheet ME7.3 as an idea;

1. Introduction:
Sufficient ignition energy must be made available in order that the sparking plug can ignite the mixture. This is realized by
closing the primary circuit of the ignition coil in good time so that the coil can charge up sufficiently.
On the other hand, the closing time shall not be too long as this can otherwise lead to the ignition output stage overheating
(particularly critical for internal output stages).
After closing, the primary current i increases exponentially with time. The period of time from the primary circuit closing to
opening again (sparking) is referred to as the dwell time.
The energy stored in the magnetic field is given by :
W = 1/2 * L * iˆ2 (L: inductance, i: current flowing at the point in time that the primary circuit opens)
2. Calculation of the dwell time:
The dwell time szout is calculated from a map that depends on the speed and battery voltage, corrected by a factor depending on the
engine temperature (from characteristic FSZTM).
3. Dependency of the dwell time:
ub: The primary current i flows through the primary winding of the ignition coil. This is determined by the battery voltage ub
and the resistance of the coil.
nmot: Above an engine-speed threshold, the dwell time is computed as a dwell angle and output at an angle level.
Thus a speed-dependent lead by the dynamics is required here so that a sufficiently long dwell time is still given even
in the event of maximum speed dynamics. The dynamics lead is taken into account in the map KFSZT.
The dynamics lead required is lower at higher engine speeds.
No dynamics lead is necessary in the lower engine-speed range (dwell time output).
It can also be meaningful to have a shorter dwell time at higher speeds for thermal reasons.
tmot: The ignition coil temperature changes with the engine temperature.
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RBPE
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« Reply #72 on: August 11, 2017, 07:32:25 AM »

I like the visual side too! Good for timing/fuel understanding etc;

https://www.youtube.com/watch?v=jdW1t8r8qYc
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Gaghunfv2
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« Reply #73 on: August 11, 2017, 07:44:01 AM »

Thanks RBPE! This makes sense. Smiley

=> But why is the closing time not 0 by default? I thought a good spark is good for the engine?
=> Why would a long closing time overheat the ignition coil? Longer time => Coil doesn't need to hold that much power => colder coil and a lighter spark??
=> Editing the "closing time"-maps lead to a faster ignition cut, am I right? If not editing them, the ignition cut would be a "long/slow bounce", am I right?
=> What map/value defines the ignition cut?


I like the visual side too! Good for timing/fuel understanding etc;

https://www.youtube.com/watch?v=jdW1t8r8qYc
Thanks for the recommendation, but I know how it works.
I repaired oldtimer motorcycles (mostly 2 strokes) for a few years. Smiley
« Last Edit: August 11, 2017, 07:49:40 AM by Gaghunfv2 » Logged

4ringpieces
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« Reply #74 on: August 11, 2017, 07:59:42 AM »

In kfszt.

Make rpm axis 7000, 7050(change depending on your limiters etc)

Put 0 dwell in 7050rpm row

Works in older me
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