BMW VANOS

mooseheadm5 · Post by **mooseheadm5** » Mon Oct 29, 2007 12:30 pm

BMW related (some applicable to other cars)

How about control for VANOS (single, dual, and fully variable M car)- single and dual are just solenoids activated with a ground signal based on RPM/load

DISA (dual resonance intake) - Same here, except that the early DISA only requires activation of a vacuum switch. A similar setup could be used on many vehicles in place of a stepper to control a multi-stage intake.

Secondary air (not like I care, but some people's home states require all emissions stuff to work) - On 96- BMWs (and many of the European cars I have worked on), this requires activating a relay for the air pump, and a vacuum switch for the secondary air valve based upon engine temperature for a set time (a couple of minutes.)

Tough one, cable and fly by wire electronic throttle bodies - I hate these things, but VW, Volvo, BMW and many others use them. I know for a fact that the Seimens/VDO used on 00 and later BMW 6cyl has only 6 wires: power and ground to the motor and 4 wires to a potentiometer. If need be, I can send a developer a throttle that I replaced due to intermittent potentiometer failure.

As I think of more, I'll let you know

Xtatic · Post by **Xtatic** » Tue Oct 30, 2007 6:09 am

Hey moosehead

i have a single-vanos USspec S50 motor and drive the vanos solenoid with an auxiliary circuit (a vb921 and a resistor) connected to one of the GP cpu outputs and switch it on/off depending on rpm/load

But i am also very interested in implementing the control for the dual vanos and learning to tune it (cause maybe one day i will put the aluminum block m52tu into my e30 and shave the 40lb off the nose).

I believe i know (at least in theory) what it takes to implement the continuous dual-vanos (AFAIK all dual-vanos systems are continuous, only the US single vanos is on/off type).
It will require using the two cam triggers (two hall sensors), extra PWM output and significant changes to the firmware (i don't think GPIO board is even necessary but would certainly help). And also figure out how to tune that baby (i still don't know if it is safe to play around with the full swing of dual vanos, i.e if there is a possibility of valves touching the piston at certain rpm/vanos angle combination)

Implementing control for DISA is also a great idea. The ones with on/off solenoid (m44, m52tu/m54) are ok, but i love the idea of the new continuous ones (not the double one like on n52 but i think recent v8 and v12 has those) It would be cool to get one DISA side from that v12 and retrofit it on my s50

Alex

mooseheadm5 · Post by **mooseheadm5** » Tue Oct 30, 2007 1:57 pm

Well, as far as I can tell, the M52TU and the M54 have single stage VANOS for both intake and exhaust. They have the same type of solenoid as the single, just an extra cam sensor on the exhaust to determine whether or not the VANOS is doing what it is supposed to. For all the ones I have worked on, they do not seem to care (they set a MIL, but run fine) when the exhaust cam pos sens. craps out, but the intake cam pos sens often causes no start or stall out. The S50B32 (Euro), S54, and M5 V8 and V10 (and the McLaren V12, for that matter) have continuously variable VANOS, and those setups look very different. They do not have the hump, they have various machined and allen bolted bits at the front. Anyhow, that means that single stage dual VANOS should be easy. AFAIK, you can't mash the pistons into the valves unless using an aftermarket cam, running well past the factory redline, and improperly degreeing said cam (ask my brother how he knows that, though it was not his fault.)
Have not worked on the new multi-length intakes, so I couldn't tell you there.
-Paul

maddios · Post by **maddios** » Wed Oct 31, 2007 6:53 pm

That's interesting, in that case I wonder what the ECU reports in the DIS/INPA tools when it shows the cam timing varying quite a bit with throttle/revs/load.

I'm not saying that the vanos is really fully adjustable, but i wonder if the ecu can keep it in between (since it's hydraulic it likely has quite a bit of lag) either end by opening/closing the control valves.

mooseheadm5 · Post by **mooseheadm5** » Thu Nov 01, 2007 11:41 am

I am not sure of that myself. I know that cam timing changes that occur are not instantaneous, so maybe that has something to do with it. I'll see what I can find and check back.
-Paul

Post by **efahl** » Fri Nov 02, 2007 6:50 am

The motors with dual Vanos are drive-by-wire, right? In that case, the ECU has almost certainly implemented a feed forward control system and can adjust for the latency by appropriately adjusting the throttle, watching RPMdot and applying the proper duty cycle to the actuators...

mooseheadm5 · Post by **mooseheadm5** » Fri Nov 02, 2007 8:57 am

Morbo,
M52TU motors are electric over cable throttles, and M54 are drive by wire. Otherwise, these engines are very similar. I have posted to a professional forum and will have an answer soon.
-Paul

mooseheadm5 · Post by **mooseheadm5** » Fri Nov 02, 2007 1:18 pm

Got this off of Alldata:

Functional Description VANOS (Variable Camshaft Control) :

Control unit is activated by relevant engine control unit. The control unit operates a regulating element via a solenoid. In this manner, engine oil pressure is supplied to both sides of a hydraulic plunger.

Hydraulic plunger is held in one of both possible positions by way of mechanical stops and applied engine oil pressure. A rotating splined shaft gear is integrated in hydraulic plunger. This splined shaft gear uses its helical-bevel splines to convert plunger stroke into rotation of camshaft-relative to driven chain sprocket.

Hydraulic plungers with splined-shaft gear are located in a pressure cast aluminum housing on face end of cylinder head, coaxial to intake shaft.

Nominal position of intake camshaft (advanced or retarded) are different for each engine. adjustment of camshaft is activated be relevant engine control unit depending on engine load, engine speed and coolant temperature.

The 4/2 way operating valve is designed in such a manner that when one pressure chamber is pressureized, the other is without pressure (feedback). As soon as operating valve solenoid receives current, it moves control piston against spring force into advanced position via an armature. A coil spring returns the unit to retard position. This means that, if the armature is defective or the control unit fails the camshaft will be retarded automatically.

In this manner it is still possible to start engine even when control unit fails. It would not be possible to start engine with camshaft adjusted in advanced timing direction.

Control edges of valve are designed in such a manner that emergency operation properties of engine are guaranteed even when control piston would seize in an undefined intermediate position.

It is difficult to understand. Maybe as soon as power is pulled from the solenoid, or maybe as power is reduced to the solenoid, the position adjustment stops where it is. Otherwise, it is the same as single vanos. The parts diagrams show a couple of parts that look a little different than those of the same function in single VANOS, but still largely the same setup as single.

I'm clueless as always,
-Paul