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ricric
Member Since: 27 Nov 2005
Location: Somerset
Posts: 85
  
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Here's a really basic question but I'd love to know the answer. How does the adaptive automaic gearbox, 'learn' your stule. Does this learning persist after a switch off> Zambezi Silver SE / Ebony Leather
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 27th Nov 2005 2:41 pm |
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Gareth
Site Moderator
Member Since: 07 Dec 2004
Location: Bramhall
Posts: 26701
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I can't tell you exactly how, but it does adapt. I reckon it adjusts its shift points, and downshift sensitivity based on your driving over the previous few minutes. I don't think it adapts to a long term driving style, I may be wrong.
I notice that if I drive carefully for a couple of miles, it will use fourth gear at about thirty mph, which drops the revs to about 1600. If I drive a bit faster, for a couple of miles, it won't take fourth until 35 mph, and will drop to third will little provocation.
I like the intelligence of the shift pattern, for example if you boot the throttle, and then let go, it will hold the low gear and the revs until you start accelerating again - great if you have accelerated up to a bend and want a good take off out of the bend. It also has a canny way of deciding you are going down a long hill, and will select a lower gear to give engine braking.
I think it must remember some basic parameters after switch off, I am not sure though.
It is a very good auto box, Its the best one I have ever driven.
Be careful when the engine is cold though, as there is no torque converter lock up until a certain temperature is reached. This has the effect of giving no engine braking for the first few miles which can be a bit disconcerting.
Off road it is absolutely fantastic. It is very well integrated with all the other systems.
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| 27th Nov 2005 8:05 pm |
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Winger
Site Moderator
Member Since: 15 Feb 2005
Location: UK
Posts: 3428
 
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Gareth has given you a very complete picture.
To add some technicality to his impressions, the adaptive shift (ASIS) system allows the transmission control module to receive signals that enable the TCM to calculate the way in which the vehicle is being driven. It looks at longditudinal and lateral acceleration, engine speed and torque, oil temperature, go faster pedal position and wheel speed and this allows the TCM to calculate when the vehicle is cornering, all wheels are gripping, you are braking or accelerating. This adds the continuous adaptation of the gear changes to the individual driving style of the driver. The information is stored in the control module even when the vehicle is turned off.
As Gareth also says, the gearbox has a hill mode. This is initiated by the TCM when the engine torque exceeds the theoretical load curve for normal operation. The TCM monitors this signal to determine when the vehicle is
travelling up or down a steep gradient. In hill mode the TCM adopts one of four shift maps, three uphill and one downhill. The shift map chosen
depends on the severity of the slope as determined from the engine signals and the appropriate gear is selected to assist with the ascent or descent.
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| 27th Nov 2005 8:45 pm |
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simon
Member Since: 11 Jan 2005
Location: Shropshire
Posts: 18296
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Winger wrote:Gareth has given you a very complete picture.
To add some technicality to his impressions, the adaptive shift (ASIS) system allows the transmission control module to receive signals that enable the TCM to calculate the way in which the vehicle is being driven. It looks at longditudinal and lateral acceleration, engine speed and torque, oil temperature, go faster pedal position and wheel speed and this allows the TCM to calculate when the vehicle is cornering, all wheels are gripping, you are braking or accelerating. This adds the continuous adaptation of the gear changes to the individual driving style of the driver. The information is stored in the control module even when the vehicle is turned off.
As Gareth also says, the gearbox has a hill mode. This is initiated by the TCM when the engine torque exceeds the theoretical load curve for normal operation. The TCM monitors this signal to determine when the vehicle is
travelling up or down a steep gradient. In hill mode the TCM adopts one of four shift maps, three uphill and one downhill. The shift map chosen
depends on the severity of the slope as determined from the engine signals and the appropriate gear is selected to assist with the ascent or descent.
So its very clever then really 
Makes me wish I had an auto in a way...
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| 27th Nov 2005 10:39 pm |
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Winger
Site Moderator
Member Since: 15 Feb 2005
Location: UK
Posts: 3428
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No, I think you made the right choice if you want to be in complete control.
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| 27th Nov 2005 11:09 pm |
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Gareth
Site Moderator
Member Since: 07 Dec 2004
Location: Bramhall
Posts: 26701
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simon wrote:Winger wrote:Gareth has given you a very complete picture.
To add some technicality to his impressions, the adaptive shift (ASIS) system allows the transmission control module to receive signals that enable the TCM to calculate the way in which the vehicle is being driven. It looks at longditudinal and lateral acceleration, engine speed and torque, oil temperature, go faster pedal position and wheel speed and this allows the TCM to calculate when the vehicle is cornering, all wheels are gripping, you are braking or accelerating. This adds the continuous adaptation of the gear changes to the individual driving style of the driver. The information is stored in the control module even when the vehicle is turned off.
As Gareth also says, the gearbox has a hill mode. This is initiated by the TCM when the engine torque exceeds the theoretical load curve for normal operation. The TCM monitors this signal to determine when the vehicle is
travelling up or down a steep gradient. In hill mode the TCM adopts one of four shift maps, three uphill and one downhill. The shift map chosen
depends on the severity of the slope as determined from the engine signals and the appropriate gear is selected to assist with the ascent or descent.
So its very clever then really
Makes me wish I had an auto in a way...
Simon, the money you are saving by way of better fuel economy by driving a manual will probably pay for an auto upgrade on your next car!
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| 27th Nov 2005 11:21 pm |
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ricric
Member Since: 27 Nov 2005
Location: Somerset
Posts: 85
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Gareth, Winger, Simon,
Many thanks for your technical and ever so slightly less technical replies. As you say, it seems clever, so I'm really looking forward to driving it.
Now to complete(?) my education on this what exactly is 'torque converter lock-up'?
Last edited by ricric on 29th Nov 2005 6:12 am. Edited 1 time in total
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| 28th Nov 2005 6:04 pm |
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Gareth
Site Moderator
Member Since: 07 Dec 2004
Location: Bramhall
Posts: 26701
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Quote:Now to ocmplete(?) my education on this what exactly is 'torque converter lock-up'?
Right then, the Torque Converter (TC) is comparable to the clutch in a manual car, it allows the engine to turn over at a different speed to the gearbox when necessary - ie. slipping the clutch, got it? Ok , To select a gear on a manual car you have to press the clutch down, this disconnects the engine from the gearbox.
The TC is a "fluid coupling" did you do physics? put simply, the faster the engine turns, the more torque is passed to the gearbox. On an auto, the TC needs to slip to allow the engine to keep running when its in Drive at a standstill. As soon as you raise the revs, the car moves, but the engine is always revving higher than the gearbox.
When a certain speed is reached, the TC locks up and the slippage ceases. This is better for acceleration response, and economy. If you press the accelerater more, the lock-up releases and more revs can apply more torque etc. etc. etc.
Hope you got that.
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| 28th Nov 2005 10:47 pm |
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ricric
Member Since: 27 Nov 2005
Location: Somerset
Posts: 85
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Gareth, thanks. what a lucid description. I did 'do' physics but it seems like a million years ago (from memory we had still to discover lasers and rotational forces were just so many equations). I really do appreciate your taking the time to clearly explain about TCs. I guess I'm going to have to do some reading to move me up the learning curve. [/i][/url] Zambezi Silver SE / Ebony Leather
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| 29th Nov 2005 6:17 am |
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