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Geartronic Adaptive System V70-XC70 2001

posted by someone claiming to be Bruce on Tue Oct 17 20:01 CST 2000 [RELATED]

Here's a question I've seen posted elsewhere but not answered yet. The concensus seems to be that the adaptive control system in the 2001 Geartronic transmission requires about 20 miles to familiarize itself with the driving characteristics of a driver. What happens after I've been blasting around town in a effort to get the car to know it's me and not my wife, and then I end up getting on the freeway for half an hour. Does it switch back to the economy shifting pattern since its been cruising and I have to train it all over again, or is it somehow smart enough to ignore freeway driving since there is little, if any, shifting?

It would be cool if the transmission would adapt to various drivers' styles, and then memorize them. Just unlock the door with the key fob remote control and the seat, mirrors, AND transmission would all adjust for that driver automatically!

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Re: Geartronic Adaptive System V70-XC70 2001

posted by someone claiming to be abe crombie on Wed Oct 18 06:23 CST 2000 [RELATED]

The "adaptive shift program" is adaptive only in that it continually monitors the rate and the amount of throttle application to decide the choice of fixed programs of economy or sport.

It doesn't memorize and stay locked in these two after a given person drives car.

There is some adaptive control that looks at the time a shift takes to complete and ramps up the line pressure if a shift is delayed in completion to minimize wear.

This should never be a concern though as the adaptive memory for this is only reset if the Volvo workstation is hooked to car and the adaptives are cleared. This is done when a new gearbox is installed.

If you were to reset this adaptive function and then go drive the car like a madman immediately then you might end up with harsh shifts due to that adaptive feature "relearning" shift pressure program under the wrong conditions.

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Re: Geartronic Adaptive System V70-XC70 2001

posted by someone claiming to be Bruce on Wed Oct 18 20:02 CST 2000 [RELATED]

Thanks Abe,

It makes sense that the transmission only has to choose between two shift patterns. I was thinking, incorrectly, that it was probably more complicated than that. I wonder why it takes 20 miles (or so some say) to figure out which pattern to follow?

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Re: Geartronic Adaptive System V70-XC70 2001

posted by someone claiming to be dave on Thu Oct 19 11:04 CST 2000 [RELATED]

> It makes sense that the transmission only has to choose between two

> shift patterns.

I disagree (in a technological sense).

> I was thinking, incorrectly, that it was probably

> more complicated than that.

Same here.

It *SHOULD* be more complicated than that. If the algorithm can decide

on-the-fly what it should be doing, why must it then only choose between

the same two maps I have in my 6-yr-old car with manual selector switch?

More sophisticated systems offer either a choice among/between more fixed

maps or else use dynamic maps generated on-the-fly.

It's a shame that Volvo was not sufficiently sophisticated to utilize the

technology for the drivers' benefit, and instead only used it to cheapen

(and lighten) the car by the removal of a physical switch.

I like the fact that both my TRACS and ECAT control switches are stupid

and physical and stay put in the mode I've left them. I'd rather blame

myself for a switch being in the wrong position than futilely cursing

Volvo for being unable to read my mind properly. (I'm the same way about

auto-focus in camcorders -- unless the auto-focus works very well and fast,

I'd rather do it myself!)

It's only when the removal of a control or addition of a new technology

offers a car the ability to do something it could not do [as well] before

(without the change) that I see newer technology as an advance.

- Dave; '95 854T, 101K mi

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Re: Geartronic Adaptive System V70-XC70 2001

posted by someone claiming to be abe crombie on Thu Oct 19 05:21 CST 2000 [RELATED]

It doesn't take 20 miles for this function to be activated.

On a new car there might be the eprception of something like this due to the normal adaptation process for the shifting to get completed.

The "adaptive shift program", the thing that decides whether you are driving sporty or driving economically, does its program choice in thousandths of a second.

The idea behind getting rid of the switch used on earlier 850's, s-v-c70's, and the -2000 s-v40's is to do away with a situation where you driving conservatively and you come upon say a farm machine driving in the hroad and you need to pass it quickly but not superfast. In 'E' mode the trans would likely not downshift unless you went hard to the floor, whereas if you depressed the 'S' button you would get better acceleration when the more sensitive 'S' program gives you a part-throttle downshift.

The adaptive shift program will detect that you moved accelerator pedal aggressively and automatically goes to its 'S' mode and you get the part-throttle downshift w/o you having to plan ahead.

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Re: Geartronic Adaptive System V70-XC70 2001

posted by someone claiming to be Russell D. Ollie Sr. on Thu Oct 19 06:58 CST 2000 [RELATED]

Abe, while I agree it doesn't take 20 miles for the adaptive system to activate I don't think your description of the adaptive system is completely correct. The system is continuously adaptive so it is always working. In my experience it does take several miles to work the transmission from its most economical shift to the most sport shifts. What you described sounds a lot like the kick-down function for the car.

We have the adaptive tranny on our '99 S80 T6 and '01 V70 T5. It works pretty much the same on both but it is quicker to adjust on the T6. Here's a typical example: I get in the T6 the day after my wife has had it. I'm not a happy camper as I head out because when I step into the accelerator the tranny shifts too soon (the Mrs. drives more civil since she has our son with her typically) to give maximum acceleration (a good analogy would be the difference in feel between having DSTC on vs. off). As I leave each of the next several stop lights I continue to hammer the accelerator. After several lights you can feel the tranny start to adjust by the seat of your pants. At each successive light the car accelerates faster and faster as the tranny logic holds the lower gears longer. Eventually I get to a point where I've reached maximum acceleration capabilities and I'm happy again (and yes this is typically at least 10 miles of aggressive acceleration - not WOT though). In the V70 it works the same way but it seems to take longer for the car to swing from economical to power shifts. (At times I miss the 'E' and 'S' buttons we used to have on our 850 Turbo and S70 T5.)

Thanks.

-rdo

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Re: Geartronic Adaptive System V70-XC70 2001

posted by someone claiming to be abe crombie on Thu Oct 19 16:37 CST 2000 [RELATED]

Again, let's get something straight here: there is a use of the word adaptive that has two different meanings in the context of the transmission. Due to this, I will refer to the shift pressure regulation as "learning" instead of adaptive.

The adaptive shift control function is operational throughout the range and I did not mean to infer that it is the kickdown function. The kickdown function is only activated if you go to full throttle and then a bit more to depress the kickdown switch.

What I was referring to in the prior post was the fact that in the mode selctor switch models when in E, part throttle downshift is not going to readily occur and can leave a person with the perception that the engine is not as powerful due to having to go nearly to the floor to get a downshift whereas the same car with the switch set to S will get a part throttle downshift with little throttle depression.

The adaptive shift control analyzes the throttle motions and detects a person easing the throttle up and down as desiring a transmission that shifts early and easy and doesn't change between gears readily as that is disturbing to his quiet soul.

When this same driver gets in a situation where he needs to GO!, the trans control unit will have detected the sudden throttle changes and will downshift readily with a rapid throttle depression aand will hold out the shifts to a higher rpm/road speed where the engine is more powerful. The program is more incremental that a simple S or E mode.

The switch on the earlier models was a source of problems whenever someone perched a purse or anything else on top of mode selector switch so that the two buttons were neither one depressed fully. This would give a trans trouble indication via the flashing upshift arrow and blinking mode LEDs. Also the cost of the switch and its wiring is far more than the lines of code and an increase in memory in the control unit, especially given that the adaptive shift control is just simply better at making the trans do what one would want it to do.

There is no "learning" and memorization in this function as that defeats the instant responsiveness benfit of having this function.

On the other hand the "learning" involves the trans control unit watching gearshift duration so as to change the fluid pressure regulation when needed to prevent any slippage as indicated by a lengthier than acceptable shift.

I would guess that the subtle changes you note after you drive one of your other cars and return to the S80 has more to do with getting used to, once again, the touchy throttle response of the electronic throttle program on an S80 T6.

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