Full time lock up mode

[Bernard Fife]

gurov,

Full-time lock-up is not intended to unlock on shifts. That is why it is called "full-time" - it locks and stays locked. If the rpm is above the stall speed, there is very little slip anyhow, so locked or unlocked shouldn't matter too much.

In regular TCC mode the TCC unlocks on downshifts.

Lance.

[gurov]

gurov,

Full-time lock-up is not intended to unlock on shifts. That is why it is called "full-time" - it locks and stays locked. If the rpm is above the stall speed, there is very little slip anyhow, so locked or unlocked shouldn't matter too much.

In regular TCC mode the TCC unlocks on downshifts.

Lance.

okay, makes sense. i will disable this then for the time being.

i'm trying to get the shifts as comfortable as possible, just to see.

i was thinking fulltime lockup would be needed to send TCC to "TCC LOCKED %" when it is applied, but since that's not the case, i can rely on the normal TCC lockup to give me my lock.

[Bernard Fife]

gurov,

By far the biggest effect on shift 'firmess' is the line pressure, so you might work with that to see if you can get the shifts how you like them.

If this was mine, I would try adjusting both the line pressure table and the Max. Shift Line Pressure to start, then fine tune the Shift Pressure Adjustment Delay to get the feel you prefer.

Lance.

[gurov]

gurov,

By far the biggest effect on shift 'firmess' is the line pressure, so you might work with that to see if you can get the shifts how you like them.

If this was mine, I would try adjusting both the line pressure table and the Max. Shift Line Pressure to start, then fine tune the Shift Pressure Adjustment Delay to get the feel you prefer.

Lance.

my max shift line pressure is set to 60%. the table is all 100%'s except for idle and around 20-ish mph.

i'll try tuning these to make the engagement smoother.

[gurov]

appears that normal TCC engagement does not happen anymore.

i have fulltime TCC lock set to 7000/8000, and 6th gear, basically disable (unless there's another way to disable this)

min TCC speed is set to 30 mph, 3rd gear, i never feel TCC engage.

i want to have TCC engage with a taper, but still unlock during shifts.

[Bernard Fife]

gurov,

Taper does not depend in any way on the full-time lock-up mode, it is applied on locking the TCC whenever the TCC PWM is selected.

If not in full-time lock up mode, TCC is always disengaged on downshifts (if you aren't using the jake brake function).

Taper is used if PWM TCC mode is activated, and the start values are set.

If you have set the taper up appropriately, you shouldn't feel the TCC engage, as it happens over as many seconds as you have told it to engage, and this is the whole point of have the taper. However, it won't happen until the TCC hysteresis period has elapsed, and this is several seconds as a default value (so you might want to reduce that both the TCC taper time and the TCC hysteresis to 1.0 second or less if you are looking for TCC engagement while testing).

I have just checked the TCC PWM function and taper on the bench and these appears to work as intended (both the taper and engagement). However, if you post a datalog and an MSQ I will look further into this.

Lance.

[gurov]

okay. i will attempt to get the datalog for this

[gurov]

okay, here's the log and MSQ.

at the very start, the trans is in 4th gear, so that's 1:1, so if everything is locked, right, engine speed, input shaft, output shaft should be the same rotational speed. you can see the rises in load cause engine speed to go up, but input shaft speed and output shaft speed stay relatively unchanged.

the TCC variable remains at 0 the whole log, and the tcc engaged indicator was not on.

speed and gear are above the TCC engage point (but rpm is lower than fulltime lock)

the MSQ is not EXACTLY one from the log, but the only change is the fulltime lock setup. lock at 8000, unlock at 7000, when gear above 6 is what it was set to when the attached log was taken.

no change to the high/low tcc settings, the taper time, or the TCC locked pwm %

also, attached for reference is chop4.msl, around record 2669 and before that, around the same speed, TCC shows 100%, this is from previous firmware versions with ON/OFF tcc (engagement of which can be seen around 1635, no taper) when the load rises (in 4th gear 1:1), there's VERY little difference between output rpm and engine RPM.

that's the behavior i'm looking for. TCC unlocking during shifts, locking with a taper, always going to 100% when locked.

[Bernard Fife]

gurov,

I wouldn't use 200 for the VSS input masking, this causes issues on the bench. I would keep it to 100 or less.

However, on my bench, the TCC activates at the right initial value and proceeds to 100% over the taper period as you describe (regardless of the full time lock-up rpm settings). So I need to understand better hat is/isn't happening at your end.

Lance.

[Bernard Fife]

gurov,

I know we touched on this before, but 25.0 is *very high* for a shift hysteresis value. The recommended value is 5 to 10 mph, and always less than the value between speed bins.

190.0 kPa is also very high for the TCC limiting - it means the TCC may be applied at high loads and low speeds, and this can cause the TCC to wear out prematurely (as well as giving reduced acceleration).

To disable the full-time lock-up mode, either set the rpm high (as you did), or specify a gear higher than you actually have (like 6th for your 5 speed).

So far I am unable to find fault with the TCC operation on my bench - it engages at the initial value and climbs to 100% reliably on my bench (including after shifts). I am testing with your MSQ, at 54 mph and in 4th gear, as per your log. You might try re-downloading the latest code and re-loading it to the controller, on the chance it has been slightly corrupted.

Of course I will keep looking for any problems, though.

Lance.