Interesting change to the 2023 Kia Niro EV

[KiwiME]

I was watching a YouTube review of the 2023 Niro two nights ago and noticed something odd. Kia have significantly limited the maximum motor torque. Also see this InsideEVs article where it's thought to be a mistaken specification. I expect but have not confirmed that the 2023 Niro is still based on the same Kona/Niro drivetrain.

It's not likely a mistake because the 0-100 km/h time was much longer per the video review.



The video indicates the purpose it to achieve a high range, entirely plausible but I'll just note pessimistically that the gearbox will get a break as well. If it was for range, why not just include that in the "ECO" or "ECO+" settings and let drivers accelerate fast when they want to? It could be that a higher WLPT rating is more important in certain markets than acceleration, and they can't use ECO to achieve that.

I drew the change on this motor performance graph I just happen to have saved long ago just for comparison and to show why peak power can be quoted to be the same as the old model. The peak power limitation for motors on a torque/speed graph is the curved part and is generally for thermal reasons, getting heat out of the windings. So the curved blue line represents 201 HP when calculated from torque and RPM. RPM is derived from vehicle speed via the gear ratio, 8.206:1

 

[electriceddy]

I was watching a YouTube review of the 2023 Niro two nights ago and noticed something odd. Kia have significantly limited the maximum motor torque. Also see this InsideEVs article where it's thought to be a mistaken specification. I expect but have not confirmed that the 2023 Niro is still based on the same Kona/Niro drivetrain.

It's not likely a mistake because the 0-100 km/h time was much longer per the video review.

View attachment 16558

The video indicates the purpose it to achieve a high range, entirely plausible but I'll just note pessimistically that the gearbox will get a break as well. If it was for range, why not just include that in the "ECO" or "ECO+" settings and let drivers accelerate fast when they want to? It could be that a higher WLPT rating is more important in certain markets than acceleration, and they can't use ECO to achieve that.

I drew the change on this motor performance graph I just happen to have saved long ago just for comparison and to show why peak power can be quoted to be the same as the old model. The peak power limitation for motors on a torque/speed graph is the curved part and is generally for thermal reasons, getting heat out of the windings. So the curved blue line represents 201 HP when calculated from torque and RPM. RPM is derived from vehicle speed via the gear ratio, 8.206:1

View attachment 16557

Equally interesting is the fact of a chemistry change in the battery cells - back to higher cobalt content NCM from CATL, not the increased nickel content NCM811 cells supplied from LGES and SK On offering higher energy density.

"A decisive reason for the switch from SK Innovation (now SK On) to CATL as the supplier of the cells for the Niro EV was apparently the lower costs.

The CATL battery met (Kia’s) internal quality standards and it was decided that the supply capacity was sufficient, so we chose it instead of the domestic battery,” the Kia representative said."

Some not happy campers in S.Korea battery manufacturing facilities.

 

[cthindi]

The article also got me thinking whether many reported issues with Reducer gear box have anything to do with maximum torque?

I would not be surprised if users driving mainly in Sport mode have had more problems than those driving in Eco mode.

Although the problems are surely design or manufacturing issues. Toyota Hybrid transaxle which too has gears always in contact with each other and proximity to electric motors ( infact the motors are within the transmission) are largely trouble free

 

[KiwiME]

... whether many reported issues with Reducer gear box have anything to do with maximum torque?
I would not be surprised if users driving mainly in Sport mode have had more problems than those driving in Eco mode...

I've certainly been using a lighter foot these days for that exact reason. I noticed a few days ago that this same point was raised some time ago on a French owners forum where there are 26 pages of comments and many reported noise issues. But anecdotally there have also been less reports this year and I have to wonder what's changed?

Oh, and from Spain there's this:
https://www.change.org/p/solution-for-engine-failure-in-kia-and-hyundai-evs

 

[Zem]

I've certainly been using a lighter foot these days for that exact reason. I noticed a few days ago that this same point was raised some time ago on a French owners forum where there are 26 pages of comments and many reported noise issues. But anecdotally there have also been less reports this year and I have to wonder what's changed?

Oh, and from Spain there's this:
https://www.change.org/p/solution-for-engine-failure-in-kia-and-hyundai-evs

Hi KiwiMe.
See also:
Gearbox e-Niro:
https://forums.automobile-propre.co...ur-réducteur-anormal-sur-e-niro-64-kwh-14510/ 29 pages
Ioniq:
https://forums.automobile-propre.co...et-réducteur-transmission-à-surveiller-19985/ 12 pages

 

[Zem]

We are talking about the torque exerted by the engine, but how are the forces due to heavy braking, with triggering of the ABS, absorbed? Is there a device that limits the transmission of these jerks to the motor?

 

[Pastera]

We are talking about the torque exerted by the engine, but how are the forces due to heavy braking, with triggering of the ABS, absorbed? Is there a device that limits the transmission of these jerks to the motor?

Not certain what the weight of the rotor is but braking shouldn't place high loads on the gear train since the motor should be at maximum regeneration at the same time so the energy stored in the rotor should be reabsorbed into the battery almost instantly. Shock loads from ABS actuation could be an issue but shocks from pot holes are likely to exceed those levels by quite a bit (Dodging pot holes is essential around here if you want your front end to last)

 

[KiwiME]

Regeneration torque is similar if not exactly the same as acceleration torque. The gearbox torque rating is not simply a matter of maximum gear strength but also that of obtaining the required lifetime under typical operating conditions, which is not full torque all the time. Because shock loading in general is unpredictable (in both cases) the basic gearbox strength will have a sizable design factor applied to accommodate that, perhaps around 2. It might even be higher because the motor inertia is more rigidly coupled than an ICE (engine) would be; there is no partial decoupling present like that provided by a clutch hub or torque converter.

So, it may be that Hyundai/Kia has decided to derate the current gearbox design torque rating due to excessive warranty claims. We will know for sure once the 2023 Kona specs are available. The way it was handled on the Niro to some extend hides the change because the power value can be conveniently left the same at 150 kW with no ill effect on the gearbox. I don't think this sort of change is that unusual in the industry. It's just a technical adjustment to reduce financial losses. Few buyers would notice this and in practical terms it's still quick enough and top speed will be the same.

I'll note that this is one area Tesla don't skimp on despite using a few other compromises to maximise their margins.

 

[Ginginova]

They are not derating the gearbox design.
They are probably derating torque and therefore power applied by electric motor inside specific rpm range. Most probably software wise.

Otherwise putting some sort of over-load protection "clutch" between electric motor and gearbox is always a good design choice. Even in my mechanical engineering school days this was mandatory choice for electrically driven gear boxes, otherwise you got some bad grades.

 

[Jim Matthews]

They are probably derating torque and therefore power applied by electric motor inside specific rpm range. Most probably software wise.

Even in my mechanical engineering school days this was mandatory choice for electrically driven gear boxes, otherwise you got some bad grades.

This sounds like the working model for manufacturing, going forward. The Toyota e-CVT deploys magnetic reluctance to avoid the sort of failures Hyundai's second generation electric motors have developed (including mine).

It feels as if these are Beta test failures, foisted on the consumer.

 

[KiwiME]

Based on further info provided on the Kia Niro forum it seems that the new model 2023+ Kia Niro EV, despite having the same name, is a much different EV than the outgoing model, more than just in appearance. It has the same 'wet' oil-cooled motor design, closely-integrated with the gearbox like the Ioniq 5/EV6 but with '400V' architecture, and with V2L. This should eliminate the gearbox and motor issues present in the outgoing model.

Obviously the next Kona revision should be much the same, although it's curious that it has yet to be released. Perhaps that's due to the timing of the intermediate Series 2 (facelift) version.

Most welcome is that the Kia's coolant is conventional and there is no change requirements until 180,000 km (or 10 years) in the 'normal' schedule according to the owner's manual. Let's hope that Hyundai do the same.

The cabin filter and brake fluid have the same 2-year interval. Canada ('severe' schedule) has a gear oil change at 120,000 km as before, but it's a synthetic ATF and a lot more of it, 2.9 litres.

 

[ansonchappell]

Canada ('severe' schedule) has a gear oil change at 120,000 km as before, but it's a synthetic ATF and a lot more of it, 2.9 litres.

Interestingly, yesterday I asked my dealer to do the gear oil change now as a precaution (I'm at 6000km) and the service manager said that they couldn't, it was too early.

 

[KiwiME]

If you don't have another dealer you can ask, any local shop should have no trouble doing this.
1.05 litre of Redline MT-LV, torque plugs to 30 lb-ft.

Optionally install a magnetic drain plug, Votex DP-007 off Amazon.