MikeH
Member Since: 16 Feb 2007
Location: Eskdale
Posts: 23
|
| Active Differential-a technical explanation |
|
I would appreciate an explanation of how the active differential works. I have tried to search on this site but have not turned up any answers that convey the mechanical principle-perhaps it is my rubbish search technique?
Looking at historic pictures posted it appears that there is an electric motor/actuator mounted above the rear diff-is this powering a mechanical linkage to compress a wet plate clutch within the diff? or is it powering a hydraulic pump to do the same? Clearly the active diff is not a dog clutch mechanism as in a normal diff lock-am I correct in assuming that there is a wet clutch pack? A plate clutch would be progressive & variable (dog clutch is either off 0% or on 100% locking) which seems to fit the description of it's operation but can it go to 100% lock & does it wear? Or is it some type of torque biasing geared differential control system?
Does anyone have have a cross sectional view through the D3 active diff?-this would be extremely informative.
Is the interaxle diff controlled in a similar manner?-a transfer box sectional drawing would be great.
I apologise for all the questions but there appears to a dearth of detailed information on this available on the web but plenty of platitudes about what it can do without the how it does it.
Mike
|
 16th Feb 2007 8:34 pm |
|
|
MikeH
Member Since: 16 Feb 2007
Location: Eskdale
Posts: 23
|
In the absence of any explanation to my enquiry of the rear diff lock mechanism operation plus similar lack of response to tempestv8's earlier request for information on the transfer box (inter-axle diff) configuration what are we to conclude?
Does anyone on this board actually know the answer or do they prefer not to post the data? Alternatively are the technical details confidential and undisclosed by Landrover? Whichever-I am suspicious/surprised about the knowledge vacuum. If Land-Rover had a secret to keep it would surely have been fully patented & hence disclosable to us minions to chatter about.
In my historic experience 4WD manufacturers are only too keen to boast about & describe their new systems & developments & explain how clever they are & superior to their competitors. Does anyone else wonder why there are no explanations whatsoever forthcoming about the specifics of the D3's 4WD transmission & differential control.
I apologise for pursuing this point but in my opinion differential control (be it inter-axle or trans-axle diffs) is absolutely fundamental to maximum cross country cabability (contrary to Landrovers decades long sustained opinion that long suspension travel would compensate for everything)
Any thoughts out there?
Best Regards
Mike
|
| 21st Feb 2007 11:06 pm |
|
|
Slimer
Site Moderator
Member Since: 06 Jan 2005
Location: Last Exit to Nowhere
Posts: 16295
|
Mike, TFC isn't around much at the mo but I suspect he'll be able to give you an sensible answer or two, meanwhile I'll see what I can dig out for you.
Have you looked on GTR?
Take a look at the cutaway photos here and especially here which may help a little to answer some of your questions The End
|
| 21st Feb 2007 11:16 pm |
|
|
chesters
Member Since: 03 Oct 2005
Location: The Toon
Posts: 698
  
|
How did you find these pictures they are great. Arctic Frost Discovery 3 TDV6 SE, Active Rear Diff, Adaptive Head Lights, Tow Pack, Ebony Leather, Roof Rails, Mantec Guard. Tasmod Stainless Sill plates. Grabber AT's. Home made mud flaps. Side Steps back on until the next time.
Last edited by chesters on 21st Feb 2007 11:49 pm. Edited 1 time in total
|
| 21st Feb 2007 11:28 pm |
|
|
simon
Member Since: 11 Jan 2005
Location: Shropshire
Posts: 18296
 
|
chesters wrote:How did you find these pictures hey are great.
been around for ages... you should have been here 2 years ago 
|
| 21st Feb 2007 11:37 pm |
|
|
Gareth
Site Moderator
Member Since: 07 Dec 2004
Location: Bramhall
Posts: 26699
|
speaking from experience of a muddy slope last weekend, the D3 got just as far as the D1 and RR companions. The D3 got up in one go only because it had extra power and speed, therefore momentum, to get to the top. On the Rocks, it was a little easier in the D3 with the auto diffs and TC.
|
| 21st Feb 2007 11:41 pm |
|
|
DG
Site Moderator
Member Since: 12 Dec 2005
Location: The Gaff
Posts: 50934
|
Also.... have a read of this Land Rover US patent I found. I'm not so sure it will answer your question to the extent you require but nevertheless, it has some interesting info concerning the traction control system.
http://www.google.com/patents?vid=USPAT675...ck#PPP1,M1 21 year LR veteran > D2 GS 2003 > D3 S 2006 > D3 HSE 2009 > D4 HSE 2013 > D4 HSE 2015 > D5 HSE 2018 > DS HSE R-Dynamic P300e 2021
|
| 21st Feb 2007 11:41 pm |
|
|
Gareth
Site Moderator
Member Since: 07 Dec 2004
Location: Bramhall
Posts: 26699
|
Sorry must correct my last post, I said 'diffs' but I only have centre diff lock. I don't have a rear locker.
|
| 21st Feb 2007 11:44 pm |
|
|
Cutaway Mike
Member Since: 22 Feb 2007
Location: Virginia
Posts: 1
|
| My understanding of the electronic differential |
|
I first want to thank you all for sending viewers to my site. I am the owner of Cutaway Creations which is a US based company providing cutaway components for shows and training aids on various types of components, most of which are automotive.
I see that there has been some interest in the electronic diff that I did for Land Rover University here in the states.
The electric motor on top of the diff actuates the gears that are below it, when the big gear turns it has a "ball and ramp" assembly that compresses the clutch pack. There are potentiometers in the motor assembly that tell the control unit exactly what position the gears are in. This allows infinite adjustment of the diff clutch pack. There is a video that shows the diff working on my site. The display model has a built in battery and switch that allows it to work for training purposes.
This "electronic diff" is not really the same as a true "locking diff' which literally locks the diff. An example of a locking diff would be those supplied by ARB which use air to operate a piston which engages cogs that lock the diff or the manually locked center diff that is found in old Range Rover, Discovery and defender vehicles.
Hope this helps and thanks again for sending viewers to my site, maybe someday they will have a need for a cutaway and give us a call for a quote.
Cheers, Mike McGhee
President, Cutaway Creations LLC
www.cutawaycreations.com
|
| 22nd Feb 2007 4:08 pm |
|
|
Cutaway Mike
Member Since: 22 Feb 2007
Location: Virginia
Posts: 1
|
| My understanding of the electronic differential |
|
I first want to thank you all for sending viewers to my site. I am the owner of Cutaway Creations which is a US based company providing cutaway components for shows and training aids on various types of components, most of which are automotive.
I see that there has been some interest in the electronic diff that I did for Land Rover University here in the states.
The electric motor on top of the diff actuates the gears that are below it, when the big gear turns it has a "ball and ramp" assembly that compresses the clutch pack. There are potentiometers in the motor assembly that tell the control unit exactly what position the gears are in. This allows infinite adjustment of the diff clutch pack. There is a video that shows the diff working on my site. The display model has a built in battery and switch that allows it to work for training purposes.
This "electronic diff" is not really the same as a true "locking diff' which literally locks the diff. An example of a locking diff would be those supplied by ARB which use air to operate a piston which engages cogs that lock the diff or the manually locked center diff that is found in old Range Rover, Discovery and defender vehicles.
Hope this helps and thanks again for sending viewers to my site, maybe someday they will have a need for a cutaway and give us a call for a quote.
Cheers, Mike McGhee
President, Cutaway Creations LLC
www.cutawaycreations.com
|
| 22nd Feb 2007 4:16 pm |
|
|
Bodsy
Site Sponsor
Member Since: 06 Nov 2006
Location: In the Clubhouse
Posts: 21361
|
 Fantastic description, very clear now. Thanks Cutaway Mike. Bodsys Brake Bible
D4/D3 Remote FBH heat kits
BAS Remaps/ EGR Blank
Transmission Flush
Software updates/enabling
Clock/ SNOTM /3Flash / 4x4Info /BT Update /Service Reset/Error Codes / Gearbox Reset
See It Here
|
| 22nd Feb 2007 4:41 pm |
|
|
nwoods
Member Since: 04 Apr 2006
Location: Southern California
Posts: 563
 
|
Cutaway Mike, your company does brilliant work, I have greatly enjoyed going through those photos and they have been a big help when I was working on Rock Sliders for my truck.
Also, your creation with the small battery powered operator got me to thinking....it seems possible to retrofit a non locker equipped LR3 with one, and have it operated manually via a switch. Would need to supply a constant voltage while it was on I should imagine...but the possibility seems to be there.
Do you agree?
Thanks again for your work and the inspiration.
Regards,
Nathan Woods
www.nextstepdesigns.com
|
| 22nd Feb 2007 5:22 pm |
|
|
PCrover
Member Since: 25 Dec 2006
Location: NorCal
Posts: 16
|
Nathon, I have been looking into the possibility "switch" activation of the electronic diff for a while now. From looking at this cutaway and video along with the diff schematic it looks very do-able. If I can find a wrecked LR3 with a locking diff I plan on giving it a go. A new diff is around $1800 plus core of $400. Gary
'06 LR3
'94 D90
|
| 22nd Feb 2007 6:08 pm |
|
|
DiscoDunc
Member Since: 08 May 2006
Location: Bristol
Posts: 16390
|
Thanks Cutaway Mike. Now I know what to do when I need the workings of my D3 explained. "Just cut it into bits"
Great site. Thanks Duncan
-----------------------------------------------------
If I'd known I was going to be so thirsty this morning I'd have drunk more beer last night.
FFRR Autobiography 4.4 SDV8 MY17
D4 HSE MY13 SOLD
FFRR 3.6 Vogue TDV8 SOLD
D4 HSE MY10 SOLD
D4 SE TECH MY15 SOLD
D4 XS MY12 SOLD
D4 HSE MY10 SOLD
D3 HSE MY06 - Re-Cycled Worldwide
|
| 22nd Feb 2007 6:14 pm |
|
|
Bodsy
Site Sponsor
Member Since: 06 Nov 2006
Location: In the Clubhouse
Posts: 21361
|
I think this will become a popular mod in years to come.
One question though? Is the Electronic Diff capable of being locked (with no detrimental effect) for a period of time? As it is at the moment, the diff switches on and off depending if needed. ISTR that it locks when under Sand (or one of the other) modes, so I assume that it woul dbe wise to have a timer or beeper to check how long you've had it switched on for?  Bodsys Brake Bible
D4/D3 Remote FBH heat kits
BAS Remaps/ EGR Blank
Transmission Flush
Software updates/enabling
Clock/ SNOTM /3Flash / 4x4Info /BT Update /Service Reset/Error Codes / Gearbox Reset
See It Here
|
| 22nd Feb 2007 6:21 pm |
|
|
