M1 Variable Camshaft Control

Support forum for users of the M1 Tune

M1 Variable Camshaft Control

Postby PEI330Ci on Sat Sep 02, 2017 9:34 pm

I'm running a BWM M54 engine with VANOS. (Continually variable inlet and exhaust camshaft control)

The M1 uses a somewhat static feed forward control strategy, where a 1D table is used to set base duty cycle on the control solenoids based on oil temp.

This wouldn't be a problem if oil pressure was constant at all RPMs, but this isn't close to being the case with this engine:

Image

As a result, I'm having a lot of trouble getting the camshaft to follow target position, regardless of PID settings. If I go more aggressive on the PID, it works at lower engine RPM, but goes into oscillation at higher engine RPMs. Changing the Feed Forward duty cycle at normal engine operating temp just causes the cam to follow target at different RPMs, but lose control at others.

It seems like the feed forward table needs to be 2D, with both engine speed and oil temp taken into account.....

Has anyone else had these issues?
PEI330Ci
 
Posts: 46
Joined: Wed Feb 27, 2013 2:58 am

Re: M1 Variable Camshaft Control

Postby MarkMc on Mon Sep 04, 2017 9:39 am

Hello,
Can you send some logging of this please. It is a bit hard to tell what is going on from just a scatter plot. Generally the cam control is not relied on at very low engine RPM, some factory ECUs even turn it of until above idle to ensure plenty of oil pressure.

Sen me some logging (not screen shots) showing examples of what you are talking about.
MarkMc
 
Posts: 589
Joined: Thu May 01, 2008 12:28 pm

Re: M1 Variable Camshaft Control

Postby Blu302 on Fri Dec 22, 2017 1:34 pm

I have just gone through the same setup with an M800.

I have found that the oil temp doesn't have much affect. I used rpm as the input to the cam duty correction table as what is done in the factory MS43 ECU.

Of course oil pressure would be better but the factory setup runs a low pressure switch which I have not changed from.
____________________________________________________________________________

Blu302
BMW E46 M52TUB25 w/ cams, headers, exhaust, CAI
User avatar
Blu302
 
Posts: 127
Joined: Mon Jan 18, 2010 7:03 pm
Location: Melbourne

Re: M1 Variable Camshaft Control

Postby Herrubermensch on Sat Jan 19, 2019 2:15 pm

Did this get resolved? How? Inquiring minds want to know!

--Peter
Herrubermensch
 
Posts: 125
Joined: Mon May 07, 2012 12:37 pm

Re: M1 Variable Camshaft Control

Postby PEI330Ci on Sat Jan 19, 2019 9:10 pm

Herrubermensch wrote:Did this get resolved? How? Inquiring minds want to know!

--Peter


Peter,

Yes, Mark McCoy @ Motec worked with me via email to help sort it out.

My biggest issue was that I didn't have the feed forward gain setup properly.

If anyone is starting this process from scratch, I highly recommend High Performance Academy's Motec M1 course which gives a step by step explanation of how to setup variable camshaft control.

https://www.hpacademy.com/courses/motec ... -tutorial/


Once I had the feed forward at a point for each camshaft where it would hold the position steady, I started increasing the PIDs under running conditions to try to stabilize the actual position vs target position. On the exhaust VANOS I ended up at 35% DC, and on the inlet VANOS it was 75%.

Note: the inlet VANOS uses "inverting" on the signal so the DC goes down to move the camshaft position from resting.

A cautionary note: I switched the exhaust camshaft control from "normal" to "inverting" with the engine running and the resulting instantaneous force on the VANOS caused it to break the control spline on the camshaft. I had to tear into the top end of the engine to fix what was effectively a tuning error...
PEI330Ci
 
Posts: 46
Joined: Wed Feb 27, 2013 2:58 am

Re: M1 Variable Camshaft Control

Postby Herrubermensch on Sun Jan 20, 2019 3:44 am

PEI330Ci wrote:
Herrubermensch wrote:Did this get resolved? How? Inquiring minds want to know!

--Peter


Peter,

Yes, Mark McCoy @ Motec worked with me via email to help sort it out.

My biggest issue was that I didn't have the feed forward gain setup properly.

If anyone is starting this process from scratch, I highly recommend High Performance Academy's Motec M1 course which gives a step by step explanation of how to setup variable camshaft control.

https://www.hpacademy.com/courses/motec ... -tutorial/


Once I had the feed forward at a point for each camshaft where it would hold the position steady, I started increasing the PIDs under running conditions to try to stabilize the actual position vs target position. On the exhaust VANOS I ended up at 35% DC, and on the inlet VANOS it was 75%.

Note: the inlet VANOS uses "inverting" on the signal so the DC goes down to move the camshaft position from resting.

A cautionary note: I switched the exhaust camshaft control from "normal" to "inverting" with the engine running and the resulting instantaneous force on the VANOS caused it to break the control spline on the camshaft. I had to tear into the top end of the engine to fix what was effectively a tuning error...


Wow, Adam, thank you! Excellent help!

--Peter
Herrubermensch
 
Posts: 125
Joined: Mon May 07, 2012 12:37 pm

Re: M1 Variable Camshaft Control

Postby 01-0041 on Tue Sep 15, 2020 11:49 am

PEI330Ci wrote:
Herrubermensch wrote:Did this get resolved? How? Inquiring minds want to know!

--Peter


Peter,

Yes, Mark McCoy @ Motec worked with me via email to help sort it out.

My biggest issue was that I didn't have the feed forward gain setup properly.

If anyone is starting this process from scratch, I highly recommend High Performance Academy's Motec M1 course which gives a step by step explanation of how to setup variable camshaft control.

https://www.hpacademy.com/courses/motec ... -tutorial/


Once I had the feed forward at a point for each camshaft where it would hold the position steady, I started increasing the PIDs under running conditions to try to stabilize the actual position vs target position. On the exhaust VANOS I ended up at 35% DC, and on the inlet VANOS it was 75%.

Note: the inlet VANOS uses "inverting" on the signal so the DC goes down to move the camshaft position from resting.

A cautionary note: I switched the exhaust camshaft control from "normal" to "inverting" with the engine running and the resulting instantaneous force on the VANOS caused it to break the control spline on the camshaft. I had to tear into the top end of the engine to fix what was effectively a tuning error...


Adam,

Are the settings you and Mark came up with based on the Schrick cams or stock?

If either - would you be willing to share the Cam Control for both the Inlet and Exhaust to close the loop on this post?

I'm getting ready to make the transition from the S52B32 to an M54B30 and find this very interesting...

Thank you!

-

Trever
01-0041
 
Posts: 44
Joined: Thu Nov 15, 2012 8:04 am
Location: Pacific Northwest

Re: M1 Variable Camshaft Control

Postby PEI330Ci on Sat Oct 03, 2020 10:41 pm

Trever,

Are you running a turbo or N/A engine?
PEI330Ci
 
Posts: 46
Joined: Wed Feb 27, 2013 2:58 am

Re: M1 Variable Camshaft Control

Postby 01-0041 on Wed Oct 07, 2020 5:35 am

Hi Adam,

Sticking to N/A for now.

I've started down this path with my current engine to get a better understanding...

Thank you!
01-0041
 
Posts: 44
Joined: Thu Nov 15, 2012 8:04 am
Location: Pacific Northwest


Return to M1 Tune

Who is online

Users browsing this forum: Google [Bot] and 2 guests