View unanswered posts | View active topics It is currently Mon Nov 19, 2018 9:30 pm



Reply to topic  [ 14 posts ]  Go to page 1, 2  Next
Mitsi 4g63 DSM/Evo and NA Miata 4and2 CAS Decoder 
Author Message
Moderator
User avatar

Joined: Tue Jan 15, 2008 2:31 pm
Posts: 15194
Location: Home sweet home!
This just seemed like too easy a task to not take on and do, as usual, better than M$.

I grabbed the following image from another older thread in this section:

Image

And a CAS disk from my parts bin, and had a think for a while.

I came up with the following diagram:

Image

Green = instant cam sync
Blue = history based cam sync (we know what it is if there was one unknown event before)
Red = instant crank sync
Black = no sync possible

I'll implement it very soon and already have a test car organised :-)

This will be the first decoder to use multi sync level semantics, more dev, more core features, onwards and upwards :-)

Fred.

_________________
DIYEFI.org - where Open Source means Open Source, and Free means Freedom
FreeEMS.org - the open source engine management system
FreeEMS dev diary and its comments thread and my turbo truck!
n00bs, do NOT PM or email tech questions! Use the forum!
The ever growing list of FreeEMS success stories!


Wed Mar 23, 2011 2:25 pm
Profile WWW
Banned!

Joined: Sat Mar 08, 2008 3:57 am
Posts: 92
Location: Sydney, NSW, AU
Hi Fred,

I’ve also looked ways to decode this CAS.

I thought I’ll share my solution. It doesn’t have as many sync points during the cycle as your solution.

Here it is;

On each crank signal rising edge check cam signal.
. If cam signal high – Crank sync and Set CamSyncPossible flag.
. If cam signal low – Crank sync at 180 degree offset and Clear CamSyncPossible flag.

On each crank signal falling edge and CamSyncPossible, check cam signal
. If Cam signal high – Cam sync and Clear CamSyncPossible flag.
. If Cam signal low – Cam sync at 360 degree offset and Clear CamSyncPossible flag.

It only using the rising and falling edges of the crank signal.

Therefore, it’s also possible cam sync at 5 degrees before No.4 TDC.

_________________
previously: ca7


Thu Mar 24, 2011 3:35 am
Profile
Moderator
User avatar

Joined: Tue Jan 15, 2008 2:31 pm
Posts: 15194
Location: Home sweet home!
Ahh, I see your logic, except with my system, we already had Cam sync when we arrived at number 5btdc number 4 because we definitely knew that at the end of the smaller inner (cam) slot.

I prefer the inner and outer terminology, as i can't really look at it as 2 different signals, they are always perfectly aligned via a chunk of metal and another chunk of plastic. Thus every edge is a valid edge on the camshaft once synced if you know what I mean :-)

Thanks for sharing! BTW, are you a potential user of this code? If so, make sure you're in for a spin2 board when they come out :-) I'd love to start getting feedback on some of my work and fine tuning various things. A lot is rough around the edges right now, but if people start using it, that won't last because they will complain too much :-)

Fred.

_________________
DIYEFI.org - where Open Source means Open Source, and Free means Freedom
FreeEMS.org - the open source engine management system
FreeEMS dev diary and its comments thread and my turbo truck!
n00bs, do NOT PM or email tech questions! Use the forum!
The ever growing list of FreeEMS success stories!


Thu Mar 24, 2011 4:48 am
Profile WWW
Moderator
User avatar

Joined: Tue Jan 15, 2008 2:31 pm
Posts: 15194
Location: Home sweet home!
ca7 wrote:
I thought I’ll share my solution. It doesn’t have as many sync points during the cycle as your solution.

Also, I don't think it's possible to have more than what I have in the above diagram, but I would love for some smart-arse to prove me wrong on that! :-) If anyone can see a clever way to gain position in more places or faster than what I've demonstrated above, please share and we'll integrate it into the code base! I even thought about relative timing, but that involves the same edges that we already sync on, so as far as I can tell, the above is optimal. Anyone disagree? If so, please share! :-)

Fred.

_________________
DIYEFI.org - where Open Source means Open Source, and Free means Freedom
FreeEMS.org - the open source engine management system
FreeEMS dev diary and its comments thread and my turbo truck!
n00bs, do NOT PM or email tech questions! Use the forum!
The ever growing list of FreeEMS success stories!


Thu Mar 24, 2011 4:54 am
Profile WWW
Banned!

Joined: Sat Mar 08, 2008 3:57 am
Posts: 92
Location: Sydney, NSW, AU
Fred wrote:
we already had Cam sync when we arrived at number 5btdc number 4 because we definitely knew that at the end of the smaller inner (cam) slot.

Fred wrote:
I prefer the inner and outer terminology, as i can't really look at it as 2 different signals, they are always perfectly aligned via a chunk of metal and another chunk of plastic. Thus every edge is a valid edge on the camshaft once synced if you know what I mean :-)Fred.

Yes, I see it now. :)

Fred wrote:
are you a potential user of this code?

No, not for this CAS. But, I am a potential user for a generic missing tooth wheel on a Gen 1 SB chevy V8.

_________________
previously: ca7


Thu Mar 24, 2011 6:21 am
Profile
Moderator
User avatar

Joined: Tue Jan 15, 2008 2:31 pm
Posts: 15194
Location: Home sweet home!
I look forward to working with you a little more closely in a few months, then :-)

_________________
DIYEFI.org - where Open Source means Open Source, and Free means Freedom
FreeEMS.org - the open source engine management system
FreeEMS dev diary and its comments thread and my turbo truck!
n00bs, do NOT PM or email tech questions! Use the forum!
The ever growing list of FreeEMS success stories!


Thu Mar 24, 2011 9:25 am
Profile WWW
QFP80 - Contributor

Joined: Wed Apr 30, 2008 7:04 pm
Posts: 36
I like the sound of this Fred!


Tue Apr 19, 2011 12:53 pm
Profile
Moderator
User avatar

Joined: Tue Jan 15, 2008 2:31 pm
Posts: 15194
Location: Home sweet home!
http://issues.freeems.org/view.php?id=110

To keep track of work on it in a more formal way.

Aero, I'm counting on you for being my number one DSM tester! You'd best fix that engine! :-)

_________________
DIYEFI.org - where Open Source means Open Source, and Free means Freedom
FreeEMS.org - the open source engine management system
FreeEMS dev diary and its comments thread and my turbo truck!
n00bs, do NOT PM or email tech questions! Use the forum!
The ever growing list of FreeEMS success stories!


Tue Jun 14, 2011 7:22 pm
Profile WWW
Moderator
User avatar

Joined: Tue Jan 15, 2008 2:31 pm
Posts: 15194
Location: Home sweet home!
OK, checking the 4/2 DSM/Miata/MX-5 pattern with a logic analyser results in:

  • 70/110 for outers
  • 143 for long inner
  • 70 for short inner slot
  • 15 degrees from leading of long inner to leading of outer contained within long inner
  • leading inner edges 360 apart
  • sensor offset not shown

From the mitsi image above it should be:

  • 70/110 for outers
  • 180 for long inner
  • 80 for short inner
  • 56 degrees from leading of long inner to leading of outer contained within long inner
  • leading inner edges 360 apart
  • sensor offset not shown

However when testing my 4/1 disk on my truck I got the following:

  • 68.7/111.3 for outers
  • 140 for long inner
  • Not measured, but physically looks to be narrower angle than outers
  • 15 degrees from leading of long inner to leading of outer contained within long inner
  • leading inner edges 360 apart
  • 68 crank degrees offset from inner and outer sensors, irrespective of disk

So JimStim (and presumably MS2/MS3) match my results much more closely than the Mitsi diagram. In effect, if I setup my angles to match the JimStim, I can develop the code perfectly well as the edge allignment is correct, unlike the 4/1 CAS pattern. Then for a real car the edge numbers can be fine tuned to produce the best result.

Note, the above diagram could have been for a hall variant of the sensor, which interfaces exactly with the OEM ECU. I would place money that the angles are NOT the same on the hall disk as they are on the optical one. Likely two decoders (or sets of settings for them) are required to handle this properly. I await data from the real world before creating the necessary files for two variants, though.

Fred.

_________________
DIYEFI.org - where Open Source means Open Source, and Free means Freedom
FreeEMS.org - the open source engine management system
FreeEMS dev diary and its comments thread and my turbo truck!
n00bs, do NOT PM or email tech questions! Use the forum!
The ever growing list of FreeEMS success stories!


Tue Sep 27, 2011 1:33 pm
Profile WWW
Moderator
User avatar

Joined: Tue Jan 15, 2008 2:31 pm
Posts: 15194
Location: Home sweet home!
This'll likely get done pretty soon for a certain pillow hugging boy.

_________________
DIYEFI.org - where Open Source means Open Source, and Free means Freedom
FreeEMS.org - the open source engine management system
FreeEMS dev diary and its comments thread and my turbo truck!
n00bs, do NOT PM or email tech questions! Use the forum!
The ever growing list of FreeEMS success stories!


Fri Aug 31, 2012 11:51 pm
Profile WWW
Display posts from previous:  Sort by  
Reply to topic   [ 14 posts ]  Go to page 1, 2  Next

Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group
Designed by ST Software for PTF. ColorizeIt.