vavoom

I was going to say hello in some other topic, but it can be here - hello everyone :-)
When it comes to torque - that is not my nomenclature at all, that is rather science...

AWCAWD

I believe the confusion (may even be on my part some extent) comes from the lack of differentiation of "torque split" and "torque apportion". Even with the advanced Ralliart and EVO the Active Center Differential (ACD) splits the torque at 50:50% (when it is locked).
http://media.mitsubishicars.com/rele...64b06fc7e?la=1
Torque apportion on the other hand can be 100:0 or 0:100 % (e.g. putting rollers under either the two rear or the two front wheels, respectively).
I managed to find an article that describes this:http://www.awdwiki.com/en/torque+split+ratio/. Hope this helps.

vavoom

Exactly. Here is the table of torque split in our cars:


If someone doesn't undestand it - here is great movie which explains torque transfer:
https://www.youtube.com/watch?v=_HOa0aRZYpw

AWCAWD

Would you mind sharing the source of the table?
Thanks

CottageLifer

Why does lock mode vary at high speed? I thought locked was well, locked.

AWCAWD

Our 4WD Lock mode is really a misnomer and causes a lot of confusion. It never really locks. A fully locked differential can only be used in low speeds (you would compromise cornering ability). 4WD Lock mode in our cars can be used up to top speed.
The entire system receives input only from four sources: wheel speed, engine rpm, throttle position, and outside temperature (no input from steering wheel position).
For comparison, please see the attached image for inputs taken in the more advanced systems.

CottageLifer

Cool. Thanks for the explanation! I think it explains (tangentially) why my Nissan CVT (Jatco) works differently.

AWCAWD

Here is a video for various vehicles on rollers. It is a good comparison for those posted earlier for the ASX. One can see that some of the tests (e.g. the same side roller test) are quite challenging even for vehicles with advanced 4wd systems:
AWD sistems wars (testing) on rollers - YouTube

vavoom

Bryan Arnett, Manager Product Planning, gives overview of safety, options, competition, performance, etc., for journalists at new 2011 Outlander Sport Urban Crossover media launch held in Cabo San Lucas, Mexico 10.07.10 - here is the source:
2011 Mitsubishi Outlander Sport, Overview - YouTube


As AWCAWD wrote, it is just a name, this mode can be used at every speed and any conditions, it is just different (stronger) algorithm for 4WD controller. And it works, check my tests:
Mitsubishi ASX 2WD 4WD LOCK AWD test on snow & ice - RVR / Outlander Sport - YouTube
Mitsubishi ASX 1.8 DID 4WD LOCK Top Speed 200 km/h / Outlander Sport / RVR - YouTube


Are you sure about no input from steering wheel? Wikipedia says that torque at the rear wheels is reduced by a smaller degree through corners, so system must know that car is cornering... It takes data from ASTC, which monitors steering angle...
And are there any sources except attached image confirming temperature factor? To be honest, I never heard about it, but it sounds nice

When it comes to rollers, that is rather test of traction control systems than AWD. Our cars needs about 15 hm/h to engage breaks effectively, so we must keep it almost floored if we get stuck and then it will do its job great.
Interesting thing is that in 2WD mode system alows less wheel spin than in any 4WD mode:
Mitsubishi ASX - 2WD vs 4WD - traction control test on rollers - RVR / Outlander Sport - YouTube

AWCAWD

My source (the table) is also from Mitsubishi Motors so, I can only be as sure as the source (it is in the file now you also have, entitled "Mitsubishi Motors AWD technologies" presented I believe at the same Cabo San Lucas meeting).
The AWC system in our cars gets input from wheel speed (via ABS, TSC sensors) and the wheels rotate at different speeds while turning. I think your argument (concern) can be covered by this.
Furthermore, at higher speeds (this assumes dry road with good traction) only 20% of the torque is sent to the back according to your table. The user's manual states (at least for the US and Canadian customers) something like this: higher degree of wear is expected and the turning ability is compromised in 4WD lock mode. I can look it up and quote the statement, once I get a chance.
These systems are not as sophisticated as that of EVO or STI, some takes input from one source while the other from another.
Mazda's system indeed uses steering wheel position as an input. You (and those, who are interested) might want to watch again the roller test I posted above (from Youtube, conducted by a Mazda dealership) for CX-3 and XT Crosstrek. One might wonder why the test was designed and executed with turning vehicles and why the obstacle was put in the inner rear wheel. If you put the pieces together everything adds up. Adding that if the Crosstrek was manual, it had to use higher engine speed to engage the viscous coupling. You performed roller tests with neutral steering angle position (so were the tests in the 51 minute AWD test video conducted by some enthusiasts).

The temperature control also makes sense (we have a frost warning going off at 3C (~37 F)we all hate) as it factors in possible drop in friction coefficient. All the system has to look is whether the frost warning is on or not. I doubt it will act differently at 30C (86 F) or 10C (50 F), so is not really a temperature reading. This is only my interpretation. Mitsubishi Motors lists the temperature as one of the input sources.

vavoom

My user's manual doesn't say a word about any restrictions concerning Lock mode (just higher fuel consumption and tight corner brake effect at low speeds), that's why I expected that systems knows when to loosen the clutch, but that's very possible that it takes information just from the wheel speed, not from the steering wheel position.
I saw Mazda test and in fact I don't know what is the purpose of turning vehicles - if Subaru was manual, it would act the same irrespective of the steering wheel.
Do you think that our cars would perform different with turned wheels?

Temperature feature - yes, if it works, there are for sure just two algorithms with 3C border.

AWCAWD

My manual says " CAUTION! Driving on dry, paved roads in "4WD Lock" mode causes increased fuel consumption and premature tire wear." It has been a while (three years ago when my car was new) when I read it the last time but I remembered the premature wear statement.
It also says: " When turning a sharp corner in "4WD Lock "or "Lock" position at low speed a slight difference in steering may be experienced...". I think this qualifies for altered turning ability. Based on this I tend to assume that the system is primitive enough to stay in a partially locked (defined by the speed sensitive ratio) electromagnetic rear differential. Note that you have a low and a high speed bracket only. Many things in the system are kept simple (yes or no), just like temperature, speed as well. This is actually good because simple things last longer yet work well for the vast majority of the scenarios. Let us face it, how often you would have traction on only one wheel. If this happens, even extremely complex systems became hampered by it.
You would be the expert as you did the roller tests. Can you try and compare? Your first Youtube test in this topic has reached quite of an impressive number of views. Congratulations. I do not perform tests I just drive on snowy/icy road for six months. The performance of the car under such conditions impresses me even now after three years.

vavoom

This system is simple, but not as simple as in older generations of different cars which use exactly the same multiplate clutch (made by GKN Driveline). System is proactive, not reactive - difference is only at software. Lock mode doesn't switch to 4WD Auto (like most of similar systems), so there must be some intelligence in it (simple rule - the faster we go, the less torque is directed to the rear).
Situation with traction on only one wheel is very rare (it happened to me once during 5 years), but this is hard job for traction control, not AWD system (it will simply lock front and rear and that's all).
My tests on rollers were done just because I like this car and I drive it for a few years, so that was my curiosity - and I found out many interesting things which I share to other users. If I have some free time, I will test with turned wheels.
First YT test on ice was done completely by accident while driving icy hill - and it showed that this system really works great for this car.

vavoom

Recently I tested some competition... What do you think?

AWCAWD

It is an interesting comparison and thanks for feeding us with these new tests. I noticed that you used a more sudden throttle increase with the Vitara. May I assume that it is due to our exchange here in the forum? The more sudden acceleration in the Vitara enables the ABS to act sooner (as part of the traction control) and can send more torque to the wheels that have traction earlier. In the ASX test conducted some time ago (I believe the footage is taken from the archive) the throttle was applied more gradually and therefore the speed at which the ABS can intervene was reached later into the test. This is why (in my opinion) the Vitara appeared to pass the test sooner than the ASX. Great job, thanks again.