Phasers - From the top

[spack]

Easy enough to prove/disprove. The park command is is all pwms to 0%. But, unless anybody really cares, I’m not going to bother. I’ve disable auto start stop for this and other reasons.

My opinion is it would be a bit silly to not park phasers at engine stop. But I’ll believe what it tells me if I ever look

 

[Space Ghost]

Awesome post, learned a lot on how this all works

 

[nikhsub1]

Easy enough to prove/disprove. The park command is is all pwms to 0%. But, unless anybody really cares, I’m not going to bother. I’ve disable auto start stop for this and other reasons.

My opinion is it would be a bit silly to not park phasers at engine stop. But I’ll believe what it tells me if I ever look

I don't really comprehend everything in your posts but aren't they supposed to park at engine stop? And the reason for the failures is the locking pin goes ***** so they can't lock in the correct position anymore which is what causes the problem?

 

[spack]

Yes, the basic line of thinking is that at engine stop, the phasers go to their home positions forcefully under oil pressure. At the same time, the oil pressure on the side of the phaser which floats the lock pin is removed, allowing the pin to be pushed under spring force into the pin well. As the well wears, the pin is able to pushed out of the well with just the opposing cam resistance.

There is an instant at engine start where oil pressure is not adequate and the lock pin is meant to assure a known cam phase angle until the control system deems it time to take control

 

[DFS]

Just wanted to say thank you for the write up and sharing your work!

 

[spack]

My pleasure!!

 

[dsiggi]

Easy enough to prove/disprove. The park command is is all pwms to 0%. But, unless anybody really cares, I’m not going to bother. I’ve disable auto start stop for this and other reasons.

My opinion is it would be a bit silly to not park phasers at engine stop. But I’ll believe what it tells me if I ever look

if you get bored one day, id be interested.

 

[spack]

This is not an auto stop. However, it does show that parking the phasers happens during normal operation and when an engine stop might be anticipated. Sorry for the sloppy annotation.

At time 933.33, I let off the throttle. (3rd trace from bottom).

At time 958.66, the truck rolls to a stop and the engine RPM drops to a little over 500 RPM (bottom trace)

At that same time, the ECU parks the phasers. You can see the 2nd and 5th traces are the exhaust and intake, bank 1, PWM percents, and they are forced to 0 percent in both cases. This is full pressure on the homing direction of the phasers and minimum pressure on the lock pin float pressure. It's a guaranteed lock. The logic behind this is anybody's guess. It could be as I said, anticipating an engine stop. ?? Don't know. The capture here is a gen2 (2018) with 21b10 update applied.

 

[spack]

Then at time 979.5 I hit the throttle... Engine RPM responds, phasers unlock

 

[dsiggi]

This is not an auto stop. However, it does show that parking the phasers happens during normal operation and when an engine stop might be anticipated. Sorry for the sloppy annotation.

At time 933.33, I let off the throttle. (3rd trace from bottom).

At time 958.66, the truck rolls to a stop and the engine RPM drops to a little over 500 RPM (bottom trace)

At that same time, the ECU parks the phasers. You can see the 2nd and 5th traces are the exhaust and intake, bank 1, PWM percents, and they are forced to 0 percent in both cases. This is full pressure on the homing direction of the phasers and minimum pressure on the lock pin float pressure. It's a guaranteed lock. The logic behind this is anybody's guess. It could be as I said, anticipating an engine stop. ?? Don't know. The capture here is a gen2 (2018) with 21b10 update applied.

So based on it parking the phasers during normal operation, it makes the autostart - stop a moot point for wear because they would be parked already, at low RPM.