Second Generation Toyota Mirai

ssun30

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For reference the GA-N Crown is 15cm longer overall and 12cm longer wheelbase than 3IS, but only has 4cm of extra interior space.

A GA-N GS will have less interior space than the one based on New N. New N is a quite well-packaged RWD platform. With a moderate LWB stretch the ChDM Crown still has more space than GA-K Avalon with similar overall length.

It is possible to make space-efficient longitudinal cars. But the way to do that is start with a small platform then stretch the wheelbase. The BMW 3-series L and Mercedes C-class L both have comparable cabin space to the GA-K Camry at similar overall length (but with less boot space). But doing so would compromise handling dynamics (the 3-series L is a VERY sluggish car) and turning radius. The opposite is what Toyota did with GA-N: shrinking the bigger GA-L platform that is designed for much higher body rigidity and NVH standards. Doing so gives abysmal space efficiency but a really well-handling and high ride quality car.

There is no free lunch and the optimal solution in this era seems to be a transverse platform with electric axles, which is why GA-K+Direct4 is such a big deal.
 
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I still see the H² more logic than the BEV
Until there's a better infrastructure, its still niche. If you happen to live right by a fueling station in places like California (SF and LA) and drive a very routine route, it makes sense. I would probably buy a gas powered car just in case if a station were to ever go down.
 

Sulu

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Until there's a better infrastructure, its still niche. If you happen to live right by a fueling station in places like California (SF and LA) and drive a very routine route, it makes sense. I would probably buy a gas powered car just in case if a station were to ever go down.
Hydrogen infrastructure will have to include: clean hydrogen generation (hydrogen can be generated from fossil fuels but that obviously still has carbon emissions problems), storage, transportation (truck, rail, pipeline) and sale / delivery. It is still a big problem.
 

Will1991

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Ever since this Mirai was launched, I questioned myself why Toyota didn't use the same motor from the UX300e... Now I know why, and there're some technical issues to overcome.

In fact both Mirai motor (Q710) and UX300e (Q711) have been developed side by side, for them to use the same components as possible and to improve performance (low mechanical loss and high quietness) next to the 1st Mirai motor (Q410), but, what’s the problem?

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First, the voltage and current is different between EV and FCV so the number of stator coil turns isn’t the same. But even with this, there’re a lot in common:

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This (different voltage and current) is also the reason for the power difference between the Mirai and the UX300e:

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Second, cooling.
In the UX300e Toyota easily did a water connection up to a front motor radiator, but in the Mirai, being RWD isn’t as easy:

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So, Toyota used two air-cooled oil coolers placed in parallel being the transaxle. The motor oil circulates due to a electric oil pump and it cools by pressure differential:

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Pretty good in my opinion!
 

Motor

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Will1991

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From Autocar:

"Moving the stack up front has made room for a third high-pressure hydrogen tank to be added, with the combined storage of 5.6kg of liquefied hydrogen enough to offer a range of around 400 miles."

This is wrong, Toyota uses 700bar H2, in a gaseous state.... Liquified hydrogen would give the Mirai around 800 miles range... But it's considerably more expensive to make and harder to store. It would also lose some fuel with time due to natural H2 heating.
 

Levi

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just thinking, is the Mirai a ground up hydrogen car or a hydrogen converted ICEV? if the later I am thinking of this car with the new V6 diesel.....could be nice........all because V6 hybrid is only available on the very heavy LS and LC......
 

Gecko

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I will elaborate more later with pics, but @mikeavelli and I spent a decent bit of time in two Mirais last week… and loved them.

The spec sheet definitely doesn’t tell the whole story (weight/hp). It’s a great car to drive and felt pretty lively around town thanks to the batteries. Rear seat, however, is basically unusable when the front seats are adjusted for two people who are 6ft+.
 

ssun30

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I will elaborate more later with pics, but @mikeavelli and I spent a decent bit of time in two Mirais last week… and loved them.

The spec sheet definitely doesn’t tell the whole story (weight/hp). It’s a great car to drive and felt pretty lively around town thanks to the batteries. Rear seat, however, is basically unusable when the front seats are adjusted for two people who are 6ft+.
How does rear seat compare to the IS?

I know Mirai has unusable rear seats but the toyota.jp spec sheets suggest the legroom (800mm) is less than 3IS (840mm) but I think it's a typo and should be close to S220 Crown (900mm)