Driving the PHEV in the mountains - tips please!

[jaapv]

Down a snowy winding road I won't go B0. The car is a handful to hold in that condition and the last thing I am looking for is a full skid. 2 Tons out of control and a narrow bend coming up, no thank you :twisted: .BTW, I doubt whether 4WD lock makes much of a difference in those circumstances, as I don't think it is of any influence on braking.

I meant general high-skid risk conditions, the type skid correction training attempts to prepare you for. In that case B0 will give you a better chance of avoiding or controlling a spin.

 

[jaapv]

Drive is always on to both motors, but in normal mode the computer will adapt the power distribution between front and back axle with the emphasis on the front according to driving demand. 4WD lock overrides the power distribution by supplying equal power to front and rear. It functions up to 50 kph IIRC.

In serial mode, both e-motors provide the same amount of power. Torque is a bit different, but due to different gearing front and rear, force at the wheels is the same.

In parallel mode, the ICE drives the front wheels. A little power is applied to the from e-motor to eliminate E-drag. A little bit more power is applied to the rear motors, in order to make the rear wheels push the cars, rather than the car pull the rear wheels.

In parallel mode with 4WD lock engaged, the rear e-motor provides about as much power as the ICE.

So, per definition of steepndeep, it would be a true 4x4, right?

Not without a diff lock on the e-motors, I should think.

 

[Grigou]

Down a snowy winding road I won't go B0. The car is a handful to hold in that condition and the last thing I am looking for is a full skid. 2 Tons out of control and a narrow bend coming up, no thank you :twisted: .BTW, I doubt whether 4WD lock makes much of a difference in those circumstances, as I don't think it is of any influence on braking.

I meant general high-skid risk conditions, the type skid correction training attempts to prepare you for. In that case B0 will give you a better chance of avoiding or controlling a spin.

I said you were probably right, jaapv

@anko & jaapv : when I drive downhill on snow in the Alps my speed is not very high (max 60-70 kph or so) and the car is always in EV mode (even with the engine idle for heating).

Does 4WD make a difference for breaking in EV mode jaapv ? Good question. Next time, I invite you to find a long slope and to look at the MMCS diagram of power, in 4WD mode and without it, in EV mode
Anko you could use all your electronic stuff and show us the result

 

[anko]

So, per definition of steepndeep, it would be a true 4x4, right?

Not without a diff lock on the e-motors, I should think.

That definition given by steepndeep was:

There is a huge difference between 4x4 and AWD. 4x4 means that you have CONTINOUS drive on all 4 wheels always.

In my post, I tried to deal with the misconception that the PHEV does not have CONTINUOUS drive on all 4 wheels.

 

[anko]

Does 4WD make a difference for breaking in EV mode jaapv ? Good question. Next time, I invite you to find a long slope and to look at the MMCS diagram of power, in 4WD mode and without it, in EV mode
Anko you could use all your electronic stuff and show us the result

Personally, I don't think the is any difference in 4WD mode versus non 4WD mode in (serial) EV mode. From monitoring e-power consumption front versus right, I've learned the motors are providing equal power even without selecting 4WD mode, and we seem to be convinced 4WD mode does not provide a 'virtual locked center diff' by syncing RPMs or something like that (I have not had the opportunity / met the conditions to convince myself of the opposite ). And even if would did sync RPMs, it would not be able to transfer power from one end of the vehicle to the other end. So, what else would / could / should it do in (serial) EV mode?

In parallel mode it does make a difference. Either the ICE is doing 95 - 99% of the work with the rear motor pushing just a little bit or the ICE is doing half the work and the rear E-motor the other half of the work. I think you can kinda see for yourself without tools: drive 60 MPH in Charge mode. Watch SOC go up. Now hit 4WD and watch SOC go down. The rear mode consumes a lot of power and the ICE does not step up enough to compensate.

 

[Grigou]

Does 4WD make a difference for breaking in EV mode jaapv ? Good question. Next time, I invite you to find a long slope and to look at the MMCS diagram of power, in 4WD mode and without it, in EV mode
Anko you could use all your electronic stuff and show us the result

...I've learned the motors are providing equal power even without selecting 4WD mode, and we seem to be convinced 4WD mode does not provide a 'virtual locked center diff' by syncing RPMs or something like that (I have not had the opportunity / met the conditions to convince myself of the opposite ). And even if would did sync RPMs, it would not be able to transfer power from one end of the vehicle to the other end. So, what else would / could / should it do in (serial) EV mode? ...

I was talking about driving downhill in 4WD mode (or not) with regenerative breaking applied on the four wheels (or not). Just that.

In theses conditions I am not very concerned by a "virtual locked centre diff" or motors rpm. I am more interested to know if the front and rear wheels provide the same level of regen or not, in 4WD mode, and without 4WD mode.

 

[anko]

I understand. I was just explaining why I thing the 4WD button may not have any effect at all at low speeds.

I will try to monitor regen per motor with and without 4WD Lock when I get a chance .... My expectations are .... ;-)

 

[ultralights]

to quote the Mitsubishi new model introduction technical training manual for the PHEV.

"The Outlander PHEv is categorised as a permanent 4WD EV vehicle. the 4WD drive system being controlled by driver demand, road conditions and vehicle behaviour"

"Basic set-up of the 4WD system is 60% torque to the front wheels, and 40% to the rear, however this is constantly adjusted in response to driver demands, vehicle behaviour and stability demands."

"The 4WD Lock switch changes the basic set-up to 50:50 torque distribution, but as soon as road conditions allow, it will be shifted to a more efficient split of torque, which is dependent on driving mode, EV, Series or parallel and battery SOC. By using the front and rear motor, the driving force distribution can be controlled to an optimum rate from 100% rear 0% front, or 100% front 0% rear. Because of the fast response rate of the electrical motors, the torque split can be more precisely controlled which gives better stability and traction compared to the standard 4WD system with mechanical connection between front and rear wheels.

Active Yaw control AYC is achieved by manipulation of the braking system.

 

[anko]

Sorry for the picture sizes.

Without 4WD Lock:

With 4WD Lock:

Clearly you can see how driving torque is affected by 4WD lock (and I seem to have mixed up front and rear), but braking torque is not.

BTW: On the topic of efficiency on B-level, most dents in the first graph are just letting go of the throttle, but the four more or less in the middle are with braking. See how regen increases when the brake is applied? Comparing the 1st and 3rd dent in the second graph, you can see how max regen during braking is limited in B0 (1st dent) compared to B5 (3rd dent). To me, it means that more friction braking is needed in B0 than it is in B5 and thus B5 should be more efficient.

 

[Grigou]

Can't see the pictures

Are you saying that the front and rear torque are added in your results ?

 

[anko]

Can't see the pictures

Are you saying that the front and rear torque are added in your results ?

Of course they are ;-)
Let me check in a few minutes .....

 

[jaapv]

You put them in a locked dropbox account. They should be in a public folder.

 

[anko]

I don't think it is the folder. I think it is the link. How about now?

BTW: It is not really Torque, but the Torque Request signal from the PHEV ECU. Torque follows very closely, though.

 

[Grigou]

Thank you very much Anko, it becomes clearer.

So, same negative torque on each axle with or without 4WD Lock when driving downhill. Very interesting information for me : next time I can forget to push 4WD Lock on snowy roads

 

[anko]

Seems like it. Keep in mind, this is all EV speed. But I guess you are not so much interested in > 65 km/h speeds :mrgreen:

 

[Grigou]

Except for heating I never drive from the top of mountains with the ICE on, even at 110 kph :lol:

 

[anko]

Of course, you are right. These figures will probably apply up to 120 km/h or so ....

Let's see, tomorrow I am going where ...... hmmm ....

 

[anko]

(The first marker on the X-axis says 6:26 but should be 6:27 and a bit, so it looks a bit weird)

At 6:28:00, I am driving between 70 and 80 km/h (so, above parallel speed). Engine is running, but still warming up, so no parallel drive yet.
At 6:28:05, I engage 4WD Lock, explaining the shift in Torque between front and rear.
At 6:28:10, I disengage 4WD lock again.
Between 6:28:25 and 6:28:30, parallel drive kicks in. You see Front Torque dropping to 0 and Rear Torque dropping to just a little bit above 0 (to maintain 4WD characteristics, as Mitsu says).

The above suggests I did not mix up Front and Rear Torque, as I said earlier. But this would also mean that "Basic set-up of the 4WD system is 60% torque to the front wheels, and 40% to the rear, however this is constantly adjusted in response to driver demands, vehicle behaviour and stability demands." is not correct :?

Between 6:29:20 and 6:29:40, you see me rounding a roundabout, engine running but at below parallel mode speed. When I reach parallel mode speed, both Front and Rear Torque drop again.

At 6:30:20, you see me engage 4WD Lock, just before approaching the next roundabout. Rear Torque goes up. Front stays at 0, as I am still in parallel mode.
Then slowing down occurs and 6:30:30 I am speeding up again, still in 4WD Lock mode.
At 6:30:45, you see me reach parallel mode speed, still in 4WD Lock mode. Front Torque falls to 0, Rear Torque drops a bit but stays up.

 

[Grigou]

Well done Anko