HI,
Can someone give me a clue how to diagnose my problem. ???
Below 3000 the rpm curve looks very smooth in the log, but then i see sudden jumps up to +_ 100revs. This causes big inj. duty cycle oscillations which disturb my tuning. I've checked with oscilloscope the trigger signal and it looks pretty good. it is 60-2 wheel and i read the trigger log will not help me. The VEMS firmware is 1.1.96 and IGBT drivers are in use.
I will attach my graphs when find out how to do it.
(//)
Thnks,
Cam sync? Wrong vr polarisation?
I've checked polarity this weekend, and all was ok. Cam-sync is disabled.
How VEMS calculate RPM? If it is counting teeth only, revs shouldn't jump like that. the oscilloscope shows very stable VR sensor signal at all rpm. Is it possible something else to disturb the calculations?
I don't feel anything when rev the engine, just rpm gauge starts to play.
When it does oscillate in the log can you feel it? Does it ever do it on the overrun or only on neutral / positive acceleration ?
I get also a noisy RPM with jumps which can be indeed of about 100rpm, but only 3 crank trigs are in use in my case for my odd fire engine. I have concluded that rpm is simply the last angle speed at sync time so the errors are dependent of the engine speed.
It happens always when the revs are above 3000 (positive, negative, neutral and when hold revs), as the amplitude increases with RPM.
I don't feel it. I was thinking if it is possible to be very light misfire, but the fluctuation appears during deceleration when fuel is cut as well.
Looking now how to insert picture here, but can't find it.
Some log file?
tried to upload log here:
http://www.vems.hu/filethingie.php?subdir=MembersPage/yanmar
Seems rpm doesn't cause problems. But noisy MAP signal does!
What relates to rpm - do you get same non clean RPM line when free reving? It might be because of engine fluctuations against transmission.
When looking my logs i noticed duty cycle was jumping mostly when rpm play and not that much when MAP play, that's why I pointed rpm sensor. I upload in my files some trigger waves taken at high rpm with scope. They look good, but the voltage amplitude seems low +-1.5V. I want to check if that is normal.
Regarding MAP I have no idea how to test it. Will try with my air compressor first.
Is it not your boost controller acting @ 100kPa?
yes, it is off below 110kpa. I see no reason to use it when boost is low.
Is it not your boost controller acting @ 100kPa which makes that ripple on the map value?
I checked the log posted, but see no ripple in MAP value @100kpa. It is very smooth there.
sorry I meant 231kPa
You could easily use more software filtering on the MAP signal, try using 2/10 instead of 1/4.
Sometimes people do not put much thought into where they source the MAP sensor signal, it should be as far away from intake ports as possible, but clearly after the throttle. It should not be mixed with other signals, especially not wastegates and dumpvalves which are both prone to leak, and the wg sometimes has bad pulsating issues.
Other than that..
I would run lambda 0.80 and not richer, at 6000 rpm the chance of knock is much less than at lower rpm. Tune the lower rpm for 0.80 at most (torque peak) and aim for 0.83-0.85 at 6000 rpm and up. Lambda 0.75-0.76 is just off the charts too rich. This might be the cause of your problems, as the lambda reads slightly leaner towards the end of the pull - which could point to small mis-fires = free oxygen = leaner lambda reading.
Your VE table will be much flatter if you use lower values for your injector characteristics, which I'm sure are far from correct. Try idle, and change from lambda 0.90 to 1.00 (or the other way around) in the lambda target table, that should be possible without EGO correction when you have the correct injector characteristics. Your values are too high.
Use a standard MAT/TPS fuel enrichment table.
Cranking enrichment is high. You can check my Volvo config which is about as old as the firmware you're running.
http://www.savarturbo.se/~mattias/motor/vems_data/vemscfg/volvo-b230fk-1.2.0.vemscfg
If you are not using config switching, disable it.
I also recommend running firmware 1.2.11 for overall better software (use absolute recent VemsTune to upgrade).
Thank you for the info.Nobody have looked before in my logs to tell what is going on.
I didn't have time to investigate everything you said, but tried to lean lambda to 0.81. All is still the same. The exh.gas temperatures raised with 50 deg up to 990deg. I didn't know lambda target was involved in PW calculation.A lot to read still. :(
About the req.fuel value I read it is good to be twice less than real so it will allow more precise VE tuning. I may try to put 4.64 instead 3.0,when have enough time to play.
I cannot find info for now how to choose the best frequency for the boost controller, which is the same as the vems shop one.
I tried today to check for possible grounding and ignition issues, but all look fine and the primary coil signal with the scope is the same as picoscope. the grounding noise is less than 1V between + and ground near the ECU. The only thing i was surprised is that the shape of the signal between the coil (+) and the middle ground is the same as between coil(+) and ECU wire. I have VAG 3-pin COP.
I just read the duty cycle depend from RPM and PW only.
DC%= RPM*PW/12000
I started to calculate DC according the today's log and found out sometimes the calculation and the real value are different with more than 9%. Where is the mistake?
Quote from: yanmar on October 27, 2013, 05:25:00 PM
I just read the duty cycle depend from RPM and PW only.
DC%= RPM*PW/12000
I started to calculate DC according the today's log and found out sometimes the calculation and the real value are different with more than 9%. Where is the mistake?
Injector open time(delay).
Quote from: yanmar on October 27, 2013, 05:25:00 PM
I cannot find info for now how to choose the best frequency for the boost controller, which is the same as the vems shop one.
I use 25Hz for the Piersburg valve.
Looking at the MAP signal at full boost 231kPa, it seems as it the controller is instable,there is a périodicity and the amplitude of the oscillation is increasing (pumping?). You may have a coupling with the injected fuel. I would try first to flatten VE around the max boot set points to get fuel values still.
I don't have idea why is that oscillation of the boost. I increased MAP readings to 15 per cycle. Installed 1mm orifice before the boost controller. increased frequency from 21Hz to 42Hz. Zeroed PID values. Tried option 1 with T-piece to control the boost,but the valve couldn't bleed enough and the wastegate was always open(i use GT2860RS with internal waste gate). Tried the original N75 valve, but the spool began to come after 4000revs. I am planning to check with 100Hz and if same to try with manual boost controller.
Regarding DC calculation- how "inj. open time" is involved in the formula? I was thinking it is included in the PW. Is "VE current" i see in the log =PW?
Inj. delay should be fixed value,but when i calculate at different points the formula sometimes is matching the DC value in the log, but others is 9% diff. Even if I change the RPM with 100 then DC diff is not more than 3%
Sorry my piersbug valve is at 25Hz. You may have a coupling with the injected fuel. I would try first to flatten VE around the max boot set points to get the fuel values still.
Quote from: yanmar on October 28, 2013, 05:38:23 AM
I don't have idea why is that oscillation of the boost. I increased MAP readings to 15 per cycle. Installed 1mm orifice before the boost controller. increased frequency from 21Hz to 42Hz. Zeroed PID values. Tried option 1 with T-piece to control the boost,but the valve couldn't bleed enough and the wastegate was always open(i use GT2860RS with internal waste gate). Tried the original N75 valve, but the spool began to come after 4000revs. I am planning to check with 100Hz and if same to try with manual boost controller.
I had similar problem with turbosmart WG. Put chines one, and boost is flat.
Turbosmart. Small membrane area? IMHO this problem comes when spring force is on high side. Or small membrane is used. No?
Both cases means that spring can empty the chamber in very short period. 20Hz 50% duty it is 25ms. May be it is enough. and actuator moves wigwag like hell?
On the other side.... is here original Garrett WG actuator used?
High frequency on pierburg or MAC isn't solution. Already at 25Hz valid DC ranges are narrower. If higher those just stop to tick.
Whith frequency of 10Hz boost should be stable. Problem is in wg.
Don't you think the controller pid + valve should be able to be tuned in order to control the actuator what ever the actuator/wastegate is ?
I was trying to minimize PID influence until fix the issue. I use the original garett waste gate. Next to do will be to put camera below the turbo to check the actuator as GintsK said, but i crashed the car and will take some time to repair.