The GKN Multimode E-Transmission

[STS134]

Surely no need to go mountaineering - we know already that if the battery is full, regen has no effect and you have to use the mechanical brakes to slow down. Happens to me every morning in the Sarf Lundun Alps. :roll:

What is the temperature of your brake rotors after doing that? You can determine this if you have an infrared thermometer. This isn't necessarily unsafe, but it can be if the rotors are undersized for the weight of the vehicle. From an engineering perspective, you EITHER have enough heat dissipation capacity in the rotors to be able to use them continuously on a downhill slope OR you give the car the ability to dissipate kinetic energy using the ICE, OR you do both. What you do not EVER want to do is neither.

Not sure if it's undersized, but Mitsubishi did enlarge the front rotors by a noticeable 1 inch/25mm for MY2019: from 11.6 inches/295mm to 12.6 inches/320mm (also the rear increased too, though strangely the press release did not mention this. Rear rotor goes from 11.9 inches/302mm to 12.6 inches/295mm). For comparison, a 2019 Toyota Highlander with almost identical weight has 12.9 inches/328mm front and 12.2 inches/310mm rear.

I really should test this. I always carry an infrared thermometer with me in the car because on my previous car, I burned out two sets of rotors. Now that I think about it, I'm concerned about the brakes on this vehicle, once the battery SoC reaches 100% when descending a long slope.

https://www.youtube.com/watch?v=sNbMXJ2_yqU

 

[anko]

Now that I think about it, I'm concerned about the brakes on this vehicle, once the battery SoC reaches 100% when descending a long slope.

Poor lad.

 

[greendwarf]

My apologies to our relatively new US cousins if my tongue in cheek reference to the Sarf Lundun Alps misled anyone. My journey to work in the overwise flat South London involves a gradual decline to the river Thames, which allows me to coast much of the way in B0 - i.e. using little or no of the battery. Initially, at least, there is nowhere for any charge to go from regen, so if I need to slow down I noticeably have to use the mechanical brakes. However, this is all at 20 mph or less - so no danger of the discs overheating. :lol:

My real point was regarding whether Mitsu had made any other arrangement to deal with excess energy. I would say, from the above, clearly no. But that is same for any ICE car unless the driver uses engine braking, which we don't have.

So yes, those in more elevated places need to be careful.

 

[anko]

But that is same for any ICE car unless the driver uses engine braking, which we don't have.

I agree we don't have it. But I think it requires tools like PHEVWatchDog to know for sure. In theory, it would be possible that the motors are generating power that is fed back to the generator that uses it to turn over the ICE with the ignition turned off. Would we be able to tell the difference between that and friction brakes from inside the cabin? ;-)

 

[greendwarf]

But that is same for any ICE car unless the driver uses engine braking, which we don't have.

I agree we don't have it. But I think it requires tools like PHEVWatchDog to know for sure. In theory, it would be possible that the motors are generating power that is fed back to the generator that uses it to turn over the ICE with the ignition turned off. Would we be able to tell the difference between that and friction brakes from inside the cabin? ;-)

I would have thought so. If it did work as described then the car would slow without using the brakes but if the battery is full it just freewheels with no sign of "braking" unless you press the pedal.

 

[STS134]

But that is same for any ICE car unless the driver uses engine braking, which we don't have.

I agree we don't have it. But I think it requires tools like PHEVWatchDog to know for sure. In theory, it would be possible that the motors are generating power that is fed back to the generator that uses it to turn over the ICE with the ignition turned off. Would we be able to tell the difference between that and friction brakes from inside the cabin? ;-)

I would have thought so. If it did work as described then the car would slow without using the brakes but if the battery is full it just freewheels with no sign of "braking" unless you press the pedal.

But I think anko is asking if it actually does e-braking in place of regenerative braking when you press the pedal. We know that it doesn't do regen when you lift your foot off the accelerator (effectively acting like it's in 'B0' mode), but does it do e-braking when you press the brake? I'm actually not sure. Does it only do this if the ICE is already warm (to avoid turning a cold ICE)? Etc.

 

[anko]

I agree we don't have it. But I think it requires tools like PHEVWatchDog to know for sure. In theory, it would be possible that the motors are generating power that is fed back to the generator that uses it to turn over the ICE with the ignition turned off. Would we be able to tell the difference between that and friction brakes from inside the cabin? ;-)

I would have thought so. If it did work as described then the car would slow without using the brakes but if the battery is full it just freewheels with no sign of "braking" unless you press the pedal.

But I think anko is asking if it actually does e-braking in place of regenerative braking when you press the pedal. We know that it doesn't do regen when you lift your foot off the accelerator (effectively acting like it's in 'B0' mode), but does it do e-braking when you press the brake? I'm actually not sure. Does it only do this if the ICE is already warm (to avoid turning a cold ICE)? Etc.

More or less. I (we) already know it doesn't. But you need PHEVWatchDog or similar tools to tell. If it did E-braking (like reverse serial mode), a request for "negative torque" should be send to the E-motors and a request for "positive torque" should be send to the generator. But this does not happen

 

[darwiniandude]

The transmission actually stayed in series mode all the way until around 88 mph (141 km/h) at which point

... the time travel circuits activated.