Dual Actuator Vanos

[Herrubermensch]

So I think I've pretty much got my M1 Tune package set up to run a BMW S62 with one glaring exception: vanos control. The S62 runs two actuators (i.e., two solenoids) per cam, one for advance and one for retard, meaning I need code to control a total of eight actuators, four for each vanos unit. The M190 has ample half-bridge outputs for this purpose, but the GPR package code provides control for only one actuator per cam in a DOHC setup such as the S62. Before Apex writes me custom code in M1 Build to accommodate the extra four actuators, I thought I'd ping this board to see if anyone else has done it and is willing to share the package. Thanks.

--Peter

[Herrubermensch]

Answering my own thread, I understand from a couple of M1 Build developers that Motec has a dual actuator vanos module under development. Anyone have any idea when it will be released?

--Peter

[Herrubermensch]

Well, I got my hands on the Beta of this code. Without diving into the code, it was a little difficult to understand how in operation it differentiates polarity of the actuators (normal or inverting/retard or advance), but it appears that one should "set" the polarity to normal for both actuators, then use actuator 1 resource for advance and the newly added actuator 2 resource for retard. Hopefully will get a chance to do some testing soon.

--Peter

[AndrewD]

Hi Peter,

In Upcoming->Control->Camshaft Phase including Vanos

• One output is for advance and the other for retard.
• Polarity swaps the two outputs. The outputs always drive to ground
• Feedforward compensates for the dead time of the solenoids

This alternate Camshaft Phase class which adds support for the early dual solenoid vanos systems was added a while ago but we have not had any feedback from the initial user of this class. It should control the vanos systems is a satisfactory manner but any feedback is welcome.

Regards,

Andrew

[Herrubermensch]

Thanks, Andrew. When this was added to the GPR package I already had filled out for my engine, it was unclear to me how to distinguish which cam actuator was for advance and which for retard. Also, I am confused by your statement that the actuators drive to ground, as I have my each of my solenoids assign to a half-bridge output, as that is how the factory drives vanos, viz., to power. The code seems to permit this by permitting allocation of half-bridge outputs to camshaft outputs. What am I missing?

--Peter

[AndrewD]

Hi Peter,

Half bridge outputs are allowed, but that class only currently drives the outputs to ground - you can confirm this by observing the output duty cycles are always positive. This is the way the dual solenoid vanos systems were historically run with MoTeC M800 ECUs. This can change but that is the way it is currently implemented.

The purpose of each output is not clearly documented at the moment. This class was not finalised due to lack of feedback which is why it remains "hidden" in the Upcoming group.

Andrew

[Herrubermensch]

Thanks. That is disappointing because the M800 setups required modifications to the vanos to drive them to ground. They are set up from the factory to be driven to power, requiring deletion of diodes and reversal of wiring to be driven to ground. Avoiding the necessity of all of that was an advance Pectel made with its SQ6, and I would hope that this code could be revised so as to incorporate that advance and eliminate the anachronistic technique used with the M800s.

There is a group of hard core BMW programmers/users (S62 and S54) struggling with this right now and working with Neel Vasavada and Apex Speed. Anything you can do to assist us in bringing this code to the point where it can be used to run these two very popular vanos-equipped engines would be sincerely appreciated!

--Peter

[AndrewD]

HI Peter,

I had a closer look this morning and it appears I actually did add support for driving to VBAT when I created this class - sorry for the confusion. There is a parameter called Actuator Drive: select "High Side" which is documented as "The output will switch to battery positive". This should do exactly what is required for the factory wiring if OUT_HB pins are selected.

Also note that Feed Forward is used to compensate for the dead time of the dual actuator vanos. I suggest starting with Frequency at 100Hz and setting Feed Forward to 19% to achieve the 1.9ms dead time required for these actuators. You should only need to adjust proportional gain, leave the integral gain at 0.

Andrew

[Herrubermensch]

Andrew, thank you so much. You just made my night! I thought the functionality appeared to be there, but I am no coder, so I could not tell for sure. I will commence testing very soon! Thanks again. Will you be at PRI?

--Peter

[AndrewD]

Hi Peter,

Happy to help. Unfortunately it's been a few years since I've been to the trade shows but when you drop in to the stand maybe you can request my presence for next year

Andrew