BMW has many different VANOS systems. Only the M car engines have dual solenoids.
http://en.wikipedia.org/wiki/VANOS
Fero reported that Double VANOS works perfectly
- it follows the target cam position perfectly
- it is actually easier to set up than the PWM type actuator (eg. suzuki)
- but high-side driver was required (so the protection-diode need not be removed from the solenoid-connector)
- a 4-channel low-Z-extension board was modified (4 tracecuts) to act as high-side PFET driver. Using 10k Rgs resistor, and driven from p259 (or other) outputs (p259/0,p259/1 and p259/6,p259/7, remember: pairs must be neighbors), with 510 Ohm.
- high-side driver is also required for Honda, where the solenoid has 1 pin grounded to the body
Information needs some cleanup from
especially trigger setup and initial cam-position target tables.
The intake VR polarity was originally wrong (rising edge)
- interestingly, the intake actuation worked that way too. After swapping the intake-cam VR polarity (LM1815 likes VR falling edge on its input):
Note that
- exhaust-cam (which is 6+1 pulse) is connected to secondary trigger, the +1 pulse is toothcount=2
- intake-cam (6 evenly placed pulse every 120 crankdeg, tooth_cnt=4,24,44,...) is connected to third cam (therefore "exhaust target" table is relevant for intake).
- Originally 1 pulse was inside the missing-gap, so this is different: implementation needs change, at least the configlet (possibly some other change needed, like separate "measure tooth" parameter for sectrig and third trig ?)
From engine-recorded ~1190 RPM triggerlog, Marcell extracted a 16 second section:
http://www.vems.hu/files/Fero/BMW_M3/BMW_doubleVanos_correctIntakePolarity_nicePart.zip
- this, speeded up ("600%" and "700" percent in audacity) 7 and 8 times respectively, played in endless-loop, triggered v3 perfectly on the bench (~8400 and ~9600 RPM respectively), including sectrig position measurement (3d trigger was not saved into the stereo wav by VemsTune triggerlog dialog), with no trigger-errors or RPM dropouts at all.
- something is not right around the exhaust VR of the actual engine, because RPM occasionally drops to 0 around 6500 RPM. Maybe amplitude is too high ? (around +-6V at 1200 RPM, likely amplitude more than +-30V at high RPM). This is regardless of the intake cam (third trigger enabled/disabled), but problem disappears with only primary trigger (but that's not an acceptable solution as COP coils and VVTI requires camsync)
- we'll prolly need some code modification to only send the missing tooth primtrig (not all 58 teeth) so we see all relevant events in 115200 baud triggerlog upto 9000+ RPM. That should reveal what is happening in the actual engine: extra noise-pulse (seems most likely) or missing exhaust-pulse
- also note that the engine (VR sensor?) seems to behave somewhat better when cold. Maybe clearance is lowered when HOT, resulting in higher signal amplitude ?
- we only tried adding one 1k pulldown (maybe 2, 3 or 4 would help ?)