Go Back   Team-BHP > Under the Hood > Technical Stuff


Reply
 
Thread Tools Search this Thread
Old 30th June 2015, 14:24   #16
GTO
Team-BHP Support
 
GTO's Avatar
 
Join Date: Feb 2004
Location: Bombay
Posts: 47,705
Thanked: 89,157 Times
Default Re: Developing a new type of Differential

Since the only downside is lack of engine braking, why not target Automatics first? In the interest of fuel-economy, some of the new Automatics freewheel whenever you lift off! The Fiesta DCT is one such car.

I'm willing to bet good money that 99% of AT drivers never use engine braking either. Only a handful of us would manually downshift in an AT...or use 'S' mode.
GTO is offline   (2) Thanks Reply With Quote
Old 30th June 2015, 14:25   #17
Senior - BHPian
 
1100D's Avatar
 
Join Date: Jun 2006
Location: Calcutta
Posts: 4,179
Thanked: 2,358 Times
Default Re: Developing a new type of Differential

Quote:
Originally Posted by ujjjwalb View Post
the car will not have any engine braking.
With the obvious biggest disadvantage as above, especially on steep hill descents, where it may even get outright dangerous, I am beginning to question even the advantages.

Quote:
Originally Posted by ujjjwalb View Post

This diff wont have any tyre scrubbing as in case of locked diffs and LSD's.
The LSD's are not known to create tyre scrubbing even when used offroad. As the name implies, it allows "Limited Slip" after which condition the differential returns back to its normal state almost immediately (yes there is scrubbing while the LSD is working but that is required to help with traction, without which the whole purpose of a traction aiding device is lost).

Locked Diffs however create scrubbing while being used, but that is under the control of the driver and his judgement of the terrain. Again the locking is done to overcome a challenge, without which the locking mechanism itself is not needed.


Quote:
Originally Posted by ujjjwalb View Post
It'll behave like a 100% locked diff in a straight line and a 100% open diff at turns.
Now what happens to a 100% open differential in a straight line, isn't the torque split equally to both sides? Does it not behave "locked"?





Quote:
Originally Posted by ujjjwalb View Post
100% open diff at turns.
So if one driven wheel is spinning, the other wheel will get power only when the vehicle is being driven straight (how does it determine that? Steering angle?)

What if you need traction on a non-spinning driven wheel and still need to make a turn (your differential will be open, rendering the whole thing unusable)

So in most cases, this differential seems not so convenient on real world usage (hill driving etc without engine braking) and at the same time, has limited use offroad (as against the usual LSD, MLD, Locking Differential), as it can only distribute torque in a straight line (which on tarmac is anyways available on an open differential also)
1100D is offline   (4) Thanks Reply With Quote
Old 30th June 2015, 20:07   #18
Newbie
 
ujjjwalb's Avatar
 
Join Date: Jun 2015
Location: Bangalore
Posts: 9
Thanked: 13 Times
Post Re: Developing a new type of Differential

Quote:
Originally Posted by Rahul Bhalgat View Post
Will the wheels loose power while changing the lanes?
None of the wheels actually lose power. The outer wheel will be free to rotate at a speed faster than the inner wheel. If in a situation where the inner wheel loses grip and starts spinning faster and catches up to the speed of the outer wheel, then most of the torque would get transferred to the outer wheel.

Quote:
Originally Posted by GTO View Post
Since the only downside is lack of engine braking, why not target Automatics first? In the interest of fuel-economy, some of the new Automatics freewheel whenever you lift off! The Fiesta DCT is one such car.

I'm willing to bet good money that 99% of AT drivers never use engine braking either. Only a handful of us would manually downshift in an AT...or use 'S' mode.
Yeah, just today I was reading up a bit on cars that use freewheels or sprag clutches. I did realise, that this could be used in automatics.

Quote:
Originally Posted by 1100D View Post
The LSD's are not known to create tyre scrubbing even when used offroad. As the name implies, it allows "Limited Slip" after which condition the differential returns back to its normal state almost immediately (yes there is scrubbing while the LSD is working but that is required to help with traction, without which the whole purpose of a traction aiding device is lost).
I would disagree over here. Yes, LSD's do allow limited slip, but not if you're accelerating while taking a turn. I'm saying this from my own experience. I saw one of my friend's driving his ATV with a 1.5 way LSD, on road. He was driving in circles and I could see the inner wheel badly wanting to spin faster. The differential I am working on, will overcome this issue.


Quote:
Originally Posted by 1100D View Post
Now what happens to a 100% open differential in a straight line, isn't the torque split equally to both sides? Does it not behave "locked"?
In ideal conditions, it does. Now in a situation where wheel 'A' is stuck in mud and wheel 'B' is on tarmac, wheel 'B' would still receive only 50% of the torque. Whereas a differential made using my idea, would distribute more torque to wheel 'B'.
Quote:
Originally Posted by 1100D View Post
So if one driven wheel is spinning, the other wheel will get power only when the vehicle is being driven straight. What if you need traction on a non-spinning driven wheel and still need to make a turn
I've answered that in the first few lines of this post.

Quote:
Originally Posted by amit_purohit20 View Post
If you are trying to put over-running clutch (as in the case of a bicycle rear wheel) and trying to comeup with a solution to eliminate the differential, then I would like to inform you that a company called Torsen differentials has already developed it.

I had come up with the same idea long back (I had no internet access then.), but when searched on net I came to know that Torsen already manufactures it.

Having two over-running clutches at the wheel ends helps in eliminating the differential but causes loss of engine braking.

If you have a different idea, nice to know about it.
Till yesterday, my idea was quite similar to the one you've mentioned here. But, after realizing that the differential will not really be appreciated if it doesn't offer any engine braking (thanks to all you guys ), I brainstormed today and I have a solution to let engine braking happen. Now, I think my idea is unique.
ujjjwalb is offline   (1) Thanks Reply With Quote
Old 1st July 2015, 06:57   #19
Distinguished - BHPian
 
sudev's Avatar
 
Join Date: Jan 2008
Location: Gurgaon
Posts: 3,510
Thanked: 2,385 Times
Default Re: Developing a new type of Differential

@ujjjwalb - When I was young I read a quote - "The wheel is not yet invented but I already have a million of ideas to improve it"

Get your version one prototype built and working. Implement. Get feedback. You will have to go back to drawing board many times to improve or get stress, engineering, material, process tolerances correct.

Looking forward to some more details if you want this forum to help.
sudev is offline   (1) Thanks Reply With Quote
Old 1st July 2015, 11:46   #20
Senior - BHPian
 
fiat_tarun's Avatar
 
Join Date: Jan 2010
Location: Pune / Mysore
Posts: 1,113
Thanked: 582 Times
Default Re: Developing a new type of Differential

Eaton has a differential called the 'No Spin' that operates like the one you are designing. It is fully locked when the vehicle is travelling in a straight line and the outer wheel unlocks (gets free) when the vehicle takes a turn.

These differentials are used in vehicles that operate largely off road, as the unlocking and locking isn't as smooth and there is a perceptible difference in handling, besides tyre life deterioration when used mostly on good traction surfaces

http://www.eaton.com/Eaton/ProductsS...spin/index.htm

Last edited by fiat_tarun : 1st July 2015 at 11:47.
fiat_tarun is offline   (3) Thanks Reply With Quote
Old 24th September 2015, 21:01   #21
BHPian
 
Join Date: Apr 2011
Location: Pune
Posts: 521
Thanked: 450 Times
Default Re: Developing a new type of Differential

Quote:
Originally Posted by ujjjwalb View Post
Hi guys,

I am working on developing a new differential.
Hi ujjjwalb,
Is there any progress in your proposed project for a new differential?
Rahul Bhalgat is offline   Reply With Quote
Old 24th September 2015, 23:26   #22
Newbie
 
ujjjwalb's Avatar
 
Join Date: Jun 2015
Location: Bangalore
Posts: 9
Thanked: 13 Times
Default Re: Developing a new type of Differential

Quote:
Originally Posted by Rahul Bhalgat View Post
Hi ujjjwalb,
Is there any progress in your proposed project for a new differential?
Yes, there is.
I made a simple prototype to prove the concept. It worked exactly how I expected it to. I'm almost done with the final design. I will have a proper working model by the end of this year. Will post videos once its ready!
ujjjwalb is offline   (1) Thanks Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Type of Box for Alpine Type R Woofer Akshay1234 In-Car Entertainment 15 10th August 2011 15:24
Swift Type 1 and Type 2 Vajo The Indian Car Scene 19 15th January 2010 18:18
Difference between Type 1 and Type 2 Honda 1.5 gameonrwind The Indian Car Scene 7 8th August 2008 10:54
Modifiction of Type I M800 to Type II sathyaprakash Modifications & Accessories 17 3rd July 2007 21:56
esteem type 2 instrumentation in type 1 rdkarthik Modifications & Accessories 3 3rd February 2006 14:43


All times are GMT +5.5. The time now is 21:29.

Copyright 2000 - 2017, Team-BHP.com
Proudly powered by E2E Networks