We are working on a bmw m54b30 dual vanos n/a engine which has inlet and exhaust cam sensors and inlet and exhaust pwm-ed solenoid vanos.
I have tried to tuning the inlet (vems name it exhaust because of trigger setup) vanos pid but no real good result.
The exhaust refrence position seems ok, this is the balanced position, above it the can start advancing, below retarding.
The most retarded position about 112 deg on third trigger the most advanced about 150 deg. (yes it need between 0 and 4x but we didn't know to find why vems measure this, and this is just a reference so not too important.
When I tried to find the right pid values the step target change was followed well with the cam, but when I wrote an interpolated cam table, then cam can't copy the target.
This is two screenshot show what I want to explain:
(http://cosworth.hu/misc/vanos/step_target_s.png)
(http://cosworth.hu/misc/vanos/bump_target_s.png)
This is the whole log file:
http://cosworth.hu/misc/vanos/v3.3_u006652-2013.03.05-18.26.16.vemslog (http://cosworth.hu/misc/vanos/v3.3_u006652-2013.03.05-18.26.16.vemslog)
Does anybody has experience with this?
(Will be good a calc model for all pid in vemstune...which help too solve similar situation)
I did not tried on BMW yet. But on Japanese cars solenoids love the highest frequency and diode in parallel. Because valve should not vibrate.
Well, there is flyback diode parellel but maybe i change to schottky. And i will try bigger frequency, 200 Hz is the original as I know.
Did you get this running right ?
Sorry, not yet.
I''m also working on my Subaru with avcs , were i Cant control that right also
I would love to see a videoshot on a working car, of how Well the angle Can following the target, and with what pid settings that are used to control it :)
In overall biggest problem is not proper trigger angle determination. On fixed cam[engine] sec trigger angle fluctuates. Especially close to idle region. And angle control PID goes crazy. At higher rpms problem disappears. So try to get control at higher rpms first.
From same issue suffers also injector angle determination - and causes uneven idle situations.
Sadly. But again I should mention Andrey from Russia. Their firmwares use completely different algorithm for cam trigger and injector angle measuring - super steady.
Gints
Did this get anywhere?
I''m running avcs on my own subaru and it works perfect ,
But that might not be the same with the vanos system
/Skassa
Cam position measurement during transients has been improved, single solenoid VANOS control (like on the m54) has more control options now (dual VANOS like control). Expected for release in firmware 1.2.20 (when available).
Quote from: VEMS on December 17, 2013, 07:34:01 PM
Cam position measurement during transients has been improved, single solenoid VANOS control (like on the m54) has more control options now (dual VANOS like control). Expected for release in firmware 1.2.20 (when available).
will test it on s54 in near future ;)
Also problem below will get some solution?
Quote myself from here http://www.vems.hu/wiki/index.php?page=MembersPage%2FGintsK%2FBMW%2FDoubleVanos
Quote17-08-2013 I just tried camshaft control on M54B30 - double variable VANOS with two solenoid valves...
...and faced with following camshaft control problem: PWMing has wide "dead zone" where camshaft stays in fixed position. Somewhat like from 35...60%. So current strategy works very robust reqires P=255 and high I value. But once pwm crosses dead-zone margin, camshaft movement is 1)already delayed 2)too sharp.
Gints
Hello GintsK,
Yes this is included in the selectable control options.
Regards, Dave
Good news! I have two such engines planed for next season.
Also one S65 - new type V8 where intake VANOS control is planed. BMW now uses one solenoid per cam on their M-engines.
Great news, i have an M54b25 myself (daily driver in e30), to perform tests.
Regards, Dave
any news on m54? s54 works perfect, m54 problems :)
seems got cams working :)
Quote from: VEMS on December 18, 2013, 12:56:34 PM
Great news, i have an M54b25 myself (daily driver in e30), to perform tests.
Regards, Dave
Hi!
Old topic, but I am still in same situation with wide PWM
dead zone where cam angle stays fixed. Recently I find same problem on VW Golf R32 engine.
Is there some good method to get such system to work with same precision as we can on VVTs (hondas. subarus, toyotas where no dead zone exist)?
From my point of understanding algorithm should be improved with 3 bias points for PID control: 1) middle of dead zone when cam is at target 2)point (DC%) from PID starts when retard desired 3)same for advance. Something like 50% 30% 70% in real life...
Or.... did I miss something???
Regards
Gints
Hi guys,
Cam control has been improved in 1.2.34 to resolve these issues, should be ready for initial testing after the Easter weekend.
Best regards, Dave