The Future of the IS Thread

[Joaquin Ruhi]

I’m curious to see how that V6 hybrid performs in a vehicle that isn’t the LS 500h. Not a huge fan of that virtual CVT transmission.

To my knowledge, the latest Crown V6 Hybrid shares the same Frankensteinish CVT / 4-speed torque converter automatic mashup as the LC 500h and LS 500h.

 

[ssun30]

Will the two-gear transmission in the Taycan ever make sense for a PHEV or HEV? I mean Toyota already mashed up the eCVT with an auto tranny, why not just put two eCVT's in there?

That puzzled me as well. They had this exact technology developed over a decade ago to achieve the exact same goal the Taycan's 2-spd system is aiming for. They even developed that two-spd CVT to do the same thing on ICEVs (although it works differently).

Both the first gen RX400h and GS450h have a two-stage eCVT, basically attaching a second planetary gear set to the output shaft of the HSD transaxle. A launch stage with 1:1 reduction for max torque magnification and a cruise stage with 2.5:1 reduction for efficiency. For some reason they ditched all that development in favor of just a single stage system on majority of the latest TNGA hybrid systems. I guess the answer is "it's good enough". Or maybe they determined 15 years ago it didn't work as well as expected.

What you proposed totally makes sense, as it would both improve acceleration performance/uphill driving capability and reduce energy consumption at highway speeds. The 300h system would be ~15% quicker at low speeds and ~10% more efficient. And unlike the multi-stage it doesn't need to be very long and can be integrated into a transverse platform (they already did that 15 years ago after all).

The arguments against a two-stage system are 1) it's not worth the complexity 2) the reduction in electrical loss is offset by an increase in mechanical loss (compared to direct-drive) 3) very high frequency motors will eventually make it obsolete.

@Sulu @Will1991 It is possible to make a 2-stage e-CVT PSD. Lexus has already done that. The ratio change happens at the exit of the PSD, not within the PSD.

 

[Will1991]

@ssun30 , having a two stage eCVT on the older days, couldn’t be a technical requirement to the car be able to achieve higher speeds with those older electric engines?
Older electric engines on HSD’s systems were much bulkier with much lower top rotational speed, with a two stage, we can easier get near that efficiency sweet and we also can achieve higher top speeds without overspining MG2.
Now Toyota’s HSD’s electric engines, are much smaller, lighter, can spin so much faster and react so much faster than those first iteration.
I don’t know if this is true, but it’s a gut feeling, of why that happened.

 

[thtupid]

It has more to do with driving feel... With the automatic transmission you can have a more mechanical feel, for a eCVT to do the same it would require a hell of a electric engine and battery combination... And a really heavy duty gearbox to withstand those forces...

Toyota’s eCVT is quite a fit of engineering, but does lack the usual mechanical feel of a locked gear due to their construction and working principle.

This will be a oversimplification but it might help to better explain myself:
All manuals and automatics gearboxes have one input (engine flywheel) and one output (output shaft that might go to the front, to the rear,...).
If your input (engine speed) goes up, your output will go up on the same proportion (manual gearbox, DCT’s) or have some adicional ‘multiplication’ (automatic gearbox with torque converter, mainly for first and reverse, Lexus managed to have full lock-up, or act almost as a manual, on second gear with a torque converter, quite good).
Even CVT’s have only one input and one output.

But a eCVT doesn’t work like that, your output shaft depends on two inputs (Engine+MG1 and MG2). This is why you can have the same output with different engine loads. Your output shaft is a combination of two different input shafts that can work *almost* independently of each other (engine+MG1 and MG2) within some technical limits. This is why you can have 40km/h with full EV propulsion ~(with every combination possible up to)~ full engine propulsion.

Eh is this why I can hear my gears changing if I drive it hard in my IS? I totally love that little crunch noise! When I drive slow it's not there so I kinda think it is deliberate.

 

[Sebass]

I’m curious to see how that V6 hybrid performs in a vehicle that isn’t the LS 500h. Not a huge fan of that virtual CVT transmission.

Earlier in the IS discussion thread, Sulu posted a video where someone tested the V6 hybrid Crown 0-60. Although I didn't watch the video, the car apparently did the sprint in 4.7 seconds, and this is reliable info because it is not coming from the mouths of the manufacturer, but rather a reviewer who did the test themselves. 4.7 seconds is very quick, and means it completes the dash to 60 0.6 seconds faster than the LS 500h. I couldn't agree with you more though on the transmission, If I had to pick one gripe with Lexus Hybrids, it's the eCVT. Lexus may claim the 10 speed cvt in the lS and LC 500h is nothing like an eCVT, but the simulated shifts sound exactly like an eCVT.

 

[Levi]

I must be the only one to like CVTs and to prefer them not to have fake gear shifts. No shifts is what makes it so pleasant.
From a performance stand point CVTs have evolved, just as TCs.

Yeah, all brands have their weaknesses, (cough, cough, Lexus having 3 vehicles in their lineup that have been on sale for 11 + years.) 😣😢😡

That is no secret on nobody pretends this to be not true.

 

[Will1991]

Eh is this why I can hear my gears changing if I drive it hard in my IS? I totally love that little crunch noise! When I drive slow it's not there so I kinda think it is deliberate.

IS300h? What do you mean by gears changing?

From a performance stand point CVTs have evolved, just as TCs.

Well... It's almost ironical almost all journalists bashing on it's performance... But CVT's were in F1 development but FIA banned them due to being too much of an advantage...


It's so funny to see David Coulthard so young

 

[Sebass]

I must be the only one to like CVTs and to prefer them not to have fake gear shifts. No shifts is what makes it so pleasant.
From a performance stand point CVTs have evolved, just as TCs.





That is no secret on nobody pretends this to be not true.

When it comes to liking CVT's, yeah, I am not a fan. However, I agree with you that fake simulated gears are rubbish, and they detract from the point of a CVT.
As for my comments on Lexus's 3 very old and dated vehicles, I am sorry if I came off sounding like it was a secret how old these vehicles were. lol, you don't need to be told CT, GX, and LX are 10+ years old if you know what I mean.

 

[CRSKTN]

I would take fake gears on an EV than go-kart acceleration, honestly. Give me a little vibration module that replicates an engine pulling hard. Who honestly needs the ridiculous acceleration your EV can put out all the time anyways? I'd love to map a fake acceleration curve and use my EV to simulate 0-60 runs in other cars (including sound and vibration simulation).

Let me "map" an LFA to my small crossover Lexus BEV please. Sound, acceleration, everything. Stick it on a car that can outperform the LFA, and have it limit itself to what the LFA could do. Could do it for bunch of different cars. Like how your old RX drives? Your new RX EV drives the same if you want it to!

Or you can have a Yamaha tuned V10!

 

[Sebass]

I would take fake gears on an EV than go-kart acceleration, honestly. Give me a little vibration module that replicates an engine pulling hard. Who honestly needs the ridiculous acceleration your EV can put out all the time anyways? I'd love to map a fake acceleration curve and use my EV to simulate 0-60 runs in other cars (including sound and vibration simulation).

Let me "map" an LFA to my small crossover Lexus BEV please. Sound, acceleration, everything. Stick it on a car that can outperform the LFA, and have it limit itself to what the LFA could do. Could do it for bunch of different cars. Like how your old RX drives? Your new RX EV drives the same if you want it to!

Or you can have a Yamaha tuned V10!

The EV stuff sounds cool... but I'd rather have the ladder option, lol.

 

[internalaudit]

$70k CAD for the Polestar 2 BEV. Looking good for Lexus BEV pricing.

Polestar 2 - Electric performance fastback | Polestar CA

Even more engaging. Even more refined. Even more efficient. Experience our commitment to improvement with the latest iteration of Polestar 2.

www.polestar.com

 

[mikeavelli]

I guess it’s a matter of taste. A CVT in day a Prius works. No one is driving it in the mountains. But a LC is a GT so the simulated gears help accomplish this. I felt the GS 450h cvt was good but it was weird to put in manual mode with fake gears. But at the time it was a rocket when the battery was charged.

 

[CRSKTN]

$70k CAD for the Polestar 2 BEV. Looking good for Lexus BEV pricing.

Polestar 2 - Electric performance fastback | Polestar CA

Even more engaging. Even more refined. Even more efficient. Experience our commitment to improvement with the latest iteration of Polestar 2.

www.polestar.com

Built in China. I'd wait a few years.

 

[ssun30]

@ssun30 , having a two stage eCVT on the older days, couldn’t be a technical requirement to the car be able to achieve higher speeds with those older electric engines?
Older electric engines on HSD’s systems were much bulkier with much lower top rotational speed, with a two stage, we can easier get near that efficiency sweet and we also can achieve higher top speeds without overspining MG2.
Now Toyota’s HSD’s electric engines, are much smaller, lighter, can spin so much faster and react so much faster than those first iteration.
I don’t know if this is true, but it’s a gut feeling, of why that happened.

Yes, older motors have much lower max rpm (<10k rpm) so they needed two reduction ratios to cover the full speed range. You are exactly right that one reason they went with a single stage with 2.5:1 reduction is their motors can now spin much faster (>16k rpm). Same goes for Tesla's motors. The Taycan needed a second stage to achieve the top speed target.

But still, having two stages would help performance (especially with uphill driving) since more torque amplification always helps. That's how the multi-stage can be faster than the 600h system despite having 80hp less.

Eh is this why I can hear my gears changing if I drive it hard in my IS? I totally love that little crunch noise! When I drive slow it's not there so I kinda think it is deliberate.

I don't think so. A way two test this is do a WOT acceleration and you should hear a temporary drop in engine rpm at ~100km/h.

 

[internalaudit]

Built in China. I'd wait a few years.

So many things are built in China. It depends on quality control and the company but I am not interested in the Polestar 2. It's just good it is priced that way. Main stream performance (enough) BEVs below $70k CAD down the road is going to be very appealing.

 

[Carmaker1]

Let's..stay..on topic...



How confident are any of you that this vehicle will actually launch this year? I don't believe that it will, but I can be wrong of course since he haven't seen Venza at Toyota. Seems more like Jan-Dec 2021 is a big year.

 

[Will1991]

How confident are any of you that this vehicle will actually launch this year? I don't believe that it will, but I can be wrong of course since he haven't seen Venza at Toyota. Seems more like Jan-Dec 2021 is a big year.

2020 should be done for almost all the brands, Coronavirus has postponed so much to 2021... And I'm betting Geneva 2021 as a reveal for the 4IS and 2021 NAIA for the 2NX.

 

[Carmaker1]

Did it occur to anyone that the current IS rides on a Lexus exclusive platform (New N), not shared with any Toyota models? Just GS (RIP) and RC only?

As well as XF50/5LS being the first LS ever to not share a platform with a Toyota badged vehicle? Never occurred to me the Crown connections were somewhat inaccurate regarding the current car, as the IP in GS was very different from S210 and Mark X.

GS must have been expensive as hell I imagine!

Going to GA-N would mean sharing with a Toyota again lol. It's ironic, as people want TNGA, yet also want Lexus-only exclusivity.

 

[Levi]

I have no problem with RWD Toyota. Landcruiser is the best built car, and I have no issue with the Toyota badge. Lexus needs a badge to compete against the German badges. I prefer a Toyota that is better built than a German badge, or a badge that is worse built than the German cars (Jaguar, Maserati). These badges have more value for me even if their products might be inferior. In the same way a superior product has more value for me than a German badge. That is not to say some German cars have no merit, there are (were?) a number of worthy German cars, but the badge is not what makes them valuable in my eyes.

I would not mind a Lexus version of GT86, sporty, luxury but light.

 

[Will1991]

I didn't knew that New N was Lexus only, for some reason I was thinking it was a shared platform with Avensis... I was really wrong after all...

But for us, I'm sure there is so much to win going from New N to TNGA, should be considerably lighter, cheaper to manufacture (Lexus can offer more for the same price), should be more reliable and having a higher torsional rigidity.

Also, coming from some ideas going around on the GS thread:

I just love this side profile.

And it would also make sense what @Gecko said before of keeping nameplates:

IS300h, A25A-FXS is currently available in the Crown
IS350, new 4 cylinder turbo, maybe it will appear on the LS facelift, Crown offers current 8AR-FTS, shouldn't be expensive to upgrade

A BEV powertrain would be nice but I'm not getting high hopes, even a IS450h+ should be a bit tricky in my opinion.