VEMS Community Forum
Technical => Triggering => Topic started by: ZoLtaR on March 16, 2011, 08:29:52 pm
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Hi there.
I have a question about trigger configuration in my last project. The engine is 2.0L 16V with 60-2 and hall sensor on exhaust cam.
Here is my configuration of primary trigger:
(http://www.ital-performance.pl/temp/vems/primary_trigger.jpg)
And secondary trigger:
(http://www.ital-performance.pl/temp/vems/secondary_trigger.jpg)
Now I made a trigger log today and I'm little bit confused now.
http://www.ital-performance.pl/temp/vems/trigger_log1.png (http://www.ital-performance.pl/temp/vems/trigger_log1.png)
http://www.ital-performance.pl/temp/vems/trigger_log2.png (http://www.ital-performance.pl/temp/vems/trigger_log2.png)
http://www.ital-performance.pl/temp/vems/trigger_log3.png (http://www.ital-performance.pl/temp/vems/trigger_log3.png)
http://www.ital-performance.pl/temp/vems/trigger_log4.png (http://www.ital-performance.pl/temp/vems/trigger_log4.png)
It seems that every 360 degree of crank rotation logs says it's "missing tooth:1, cycle = 57" , and every 720 degree when secondary trigger occurs it's "missing tooth:1, cycle = 60"
Now why it is like that?
1) Bad VR sensor polarity?
2) Bad primary trigger configuration?
According to mattias post in other topic:
"In the case of missing-tooth, the cam sync pulse (either rising/falling) must not race with the missing teeth. It can occur any time but not there. Trigger tooth count is relative to the missing-tooth appearing after the cam sync pulse."
For me it seems that something like that occurs in my case?
What should I do now ?
Links for triggerlog files:
http://www.ital-performance.pl/temp/vems/alfa156.triggerlog (http://www.ital-performance.pl/temp/vems/alfa156.triggerlog)
http://www.ital-performance.pl/temp/vems/alfa156_triggerlog.csv (http://www.ital-performance.pl/temp/vems/alfa156_triggerlog.csv)
Thanks for help.
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For me seems that your 60-2 has physically wrong polarity. Time gap should be closer to 3. You have 2.5 and next two pulses disturbed.
For camsync just change rising to falling.
For VR 60-2 rising is a must.
Gints
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Have you possibility to check VR signal with a scope?
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Thanks for fast reply. Unfortunately I have no possibility to check it with scope now :-\
According to screenshots below primary trigger is VR and is set to rising as we can see, and camsync is also set to falling as you suggested. So this settings are correct?
Now, if I understand correctly, hall signal from cam occurs when primary VR is reading missing tooths? And this isn't ok?
I can change VR polarity and make some other logs then. But I cannot change hall signal position that is physically in conjunction with VR signal and in this case it will always occur that way (hall signal occurs during missingtooth)?
Is it possible to work this way when VR polarity will be ok ?
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Try changing falling to rising edge on the cam sync, that might move the signal enough to not race with the missing teeth, it depends on how wide the tooth is on the exhaust cam.
The trigger log says some stupid things with cam sync, that will be fixed some time in the future.
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Ok, I will try this. But VR polarity of the crank sensor is 100% wrong and I have to swap the wires?
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Yep, it's likely the VR needs a polarity change.
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Ok, I made some experiments ;) changed VR polarity and make two logs with camsync falling and rising.
Version 1)
60-2 primary trigger with camsync falling
(http://www.ital-performance.pl/temp/vems/trigger_falling.jpg)
Trigger log file http://www.ital-performance.pl/temp/vems/alfa_156_2.0_ts_vr_inverted_camsync_falling.triggerlog (http://www.ital-performance.pl/temp/vems/alfa_156_2.0_ts_vr_inverted_camsync_falling.triggerlog)
As I can see, changing the VR polarity did the job and 60-2 signal is now ok? It reads missing tooth well without any problem. Secondary trigger (falling) occurs still during missing tooth so it still can't be used.
Version 2)
60-2 primary trigger with camsync rising
(http://www.ital-performance.pl/temp/vems/trigger_rising.jpg)
Trigger log file http://www.ital-performance.pl/temp/vems/alfa_156_2.0_ts_vr_inverted_camsync_rising.triggerlog (http://www.ital-performance.pl/temp/vems/alfa_156_2.0_ts_vr_inverted_camsync_rising.triggerlog)
As mattias said, the secondary trigger signal moved about ~8 crank teeth, and now is does not race with missing teeth. Will this be enough to run camsync ?
Now, how to configure it to run fully sequential injection/ignition with that engine ? Stock firing order is 1-3-4-2.
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The last "60-2 primary trigger with camsync rising" is what you should use, looks perfect.
There's a configlet in the primary trigger dialog for setting good defaults for 60-2 with cam sync for a 6 cyl. Check it out, with 4 cyl 60-2 just add "0,90,60,30" as trigger reference teeth.
Strobe the ignition to find out what order to put the cylinders in. Only power the injectors when you are sure about the ignition and trigger settings.
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Thanks mattias!
Now, according to original firing order 1-3-4-2, trigger reference table will be set:
0 - cylinder 1
90 - cylinder 3
60 - cylinder 4
30 - cylinder 2
(http://www.ital-performance.pl/temp/vems/reference_tooth.jpg)
Now, injectors are wired in order from 1 to 4
cyl. 1 injector -> pin 7
cyl. 2 injector -> pin 19
cyl. 3 injector -> pin 8
cyl. 4 injector -> pin 20
I read that the best way is to set the injector sequence the same way as ignition sequence to achieve the best results. I mean to inject onto the closed valve of the cylinder that is actually firing.
So then, my firing order is 1-3-4-2 so I set injector group table like this:
(http://www.ital-performance.pl/temp/vems/injector_group_table.jpg)
And the same for ignition.
(http://www.ital-performance.pl/temp/vems/h%5B2%5Dtable.jpg)
Is this correct and have some chance to work? :)
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The idea is to make the rows of injection and ignition output tables relate to the same cylinder. The cylinder which fires ignition on row 0, should have its injector on row 0 of the injector output table as well.
Use a strobe light to verify the ignition order, I have no idea if that will work - to little information on the ignition outputs.
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ECU was ordered assembled with 4+4 configuration. So I wired all IGBT outputs with conjunction with cylinder order starting from cylinder 1 that is on the side of timing belt.
So I wired it up in order like below.
EC36Pin34 - cyl.1 COP
EC36Pin36 - cyl.2 COP
EC36Pin24 - cyl.3 COP
EC36Pin10 - cyl.4 COP
(http://www.ital-performance.pl/temp/vems/cops.jpg)
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You can define output <-> cyl relationships in future VemsTune versions, so this will be easier to get a grip on. For now, just make notes and use the strobe light, you'll be fine.
Use the ignition output test mode to verify correct wiring, make sure to ground the spark plugs properly when you test for spark - the current has to go somewhere, I usually use bare copper wire to create a proper ground path.
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I already make some ignition output tests and everything is ok. Plugs were grounded with thick copper wires so it's works ok. I am 100% sure about every EC36 pin.
Now about strobe light. Maybe I don't understand everything but I thougth that it's only neccessary for fine tune the TDC after the trigger value. I have original marks on flywheel / gearbox housing to do such an operation so I was planning to connect strobe to cyl. 1 coil and point strobe light to that marks.
Do I have to do it for each cylinder? ???
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You only need to do it on cyl 1, the engine will never run right if the ignition order is messed up and you have to assume the rest of the cylinders get their spark at the same advance as cyl 1 unless your trigger settings are way off.. (which they aren't).
The strobe is used to first get a clue if cyl 1 is actually even close to igniting at the correct time, the order of the table might be out. It's better to check, than assume you are correct. And yes, it's used for fine tuning later. Best is to use no advance while checking (lock timing to 0 degrees) if you are un-certain of how the strobe works, that way you can't be fooled by 2/4-stroke settings (if the strobe has the ability to delay the strobe light with the set amount of advance to light up TDC instead of actual advance).
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Now I understand a little bit more ;) Ok I will do as you said with strobe light.
The most important thing for me is the order of the ignition / injection tables, that's why i asked so many question about it. To understand things easier can I assume that I should always set injection order the same as ignition ? For example 4 cyl engine, with 1-3-4-2 firing order.
Firing Coil on cyl 1 -> Injection on cyl 1
Firing Coil on cyl 3 -> Injection on cyl 3
Firing Coil on cyl 4 -> Injection on cyl 4
Firing Coil on cyl 2 -> Injection on cyl 2
If it's okay then, screenshots of tables below should be correct.
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can I assume that I should always set injection order the same as ignition ?
Yes.
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Ok cool, now almost everything is pretty clear for me.
The hardest thing to understand for me is trigger reference tooth idea. And understanding how it should be set to a specific application.
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It is quite complicated because it is designed to support even and odd fire and many strange trigger wheels.
The trigger reference tooth which is "0", is the first trigger tooth as defined by the primary trigger settings, every TDC then follows every 30 teeth in your case (4 cyl, 60-2 trigger wheel).
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ok but in wasted spark it's always set to
0
30
0
30
in my camsync case it's set to
0
90
60
30
don't get it. :)
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It's no mystery.
Without cam sync there is no way to reference more teeth than what you have on the primary trigger wheel on one rotation = 60 teeth including the missing ones. The primary trigger count is then reset on every revolution and you can only use a distributor or wasted spark.
With cam sync the signal appears every two rotations, and it's possible to reference the entire 4-stroke cycle = 60+60 = 120 teeth, and make it possible to identify every single cylinder event.
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Thanks mattias again. Every post I know something new about triggering.
Tommorrow I will check this application with strobe light and give you a note.
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Today I checked whole system with strobe light. With 0,90,60,30 reference table i'm getting spark on cyl.1 when it is in BDC (bottom dead centre). So then it seems that whole sequence is moved 180 degree from fine position.
When I changed table to 30,0,90,60 everything seems to be fine. But it's recommended to have tooth 0 on top. So what to do now? Is there any possibility to fix it and get proper sequence with 0,90,60,30 ?
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Yes, just move the whole ignition output-table one step and you´re all set.
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Ok so reference table looks like this. ECU reads it backwards so this is proper sequence with 0 at the top (0, 90, 60 ,30). Am I right?
(http://www.ital-performance.pl/temp/vems/reference_tooth_table.jpg)
And then just adjust ignition table to suit with the trigger table events?
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Your picture is wrong, it must read :
0
90
60
30
Adjust the ignition table outputs until cyl 1 fires at the correct TDC, remember - there are two TDC situations but only one is correct with COP, both are ok with wasted spark.
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Ok I get it, but how to recognize it fires at right TDC. We have 720 deg (2 rotations) for full sequence in 4 cyl four-stroke. So how to recognize it's right for cyl.1 TDC , and do not mismatch it with cyl. 4 TDC ?
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It will only run and start with the correct order, so you can try it that way and just shift two steps in the ignition outputs if it doesn't.
.. or you can check when cyl 1 valves are closed and mark that on the cam sprocket and strobe against that.
I'd just try either of the two possible ignition orders.
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I was thinking about making mark on cam gears in position where cyl.1 should fire. That's very good idea and will give me a final answer.
In this case, cylinder 1 has a reference tooth 0 or 30 ?
0 - cyl4
90 - cyl3
60 - cyl2
30 - cyl1
or?
0 - cyl1
90 - cyl4
60 - cyl3
30 - cyl2
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You're not listing the cylinders in firing order, so it makes no sense.
Actual order : 1 3 4 2
In the ignition output table they appear like this, and you should shift the table to find which position makes cyl 1 appear in the correct place. It depends on where your cam sync pulse occurs.
2
4
3
1
This is the same table, only shifted one step :
1
2
4
3
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Allright, finally I get it to work properly. According to coil wiring ignition table now looks like below and everything works well. Every ignition event is now where it have to be. Marks on cam gear helped a lot.
4
3
1
2
Big thanks to mattias.