
How The Koenigsegg Regera Hits 248 MPH Without A Gearbox (2015) - brian-armstrong
https://jalopnik.com/how-the-1-500-hp-koenigsegg-regera-hits-248-mph-without-1689181377
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bane
The article mentions it, but this is _very_ similar to the setup in the Honda
Accord Hybrids. Many spec sheets list them as "CVT" or "e-CVT" but those are
all wrong -- there's no normal or CVT transmission at all. Instead the car is
motivated by an electric motor that can close a clutch plate (in the
Koenigsegg it's a hydraulic system probably to handle the greater HP and
torque) and engage the ICE engine. When the ICE isn't being used to help out
the electric motor it runs basically whenever it wants to and charges the
batteries.

This review from 2014 has a great explanation:
[https://www.thetruthaboutcars.com/2014/02/review-2014-honda-...](https://www.thetruthaboutcars.com/2014/02/review-2014-honda-
accord-hybrid-with-video/)

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m_mueller
A prius works in the same way, correct? In some ways this is a simpler system
than conventional ICE-only drivetrains, I think this should have been pushed
downmarket even faster than it has been. For people without the ability to
charge (e.g. in Switzerland the vast majority lives in rentals without
charging ports in the garage) this seems like the best solution so far.

~~~
pjc50
The Prius system is actually much more complicated involving a set of
planetary gears to couple torque in and out of the drivetrain. The Koenigsegg
system doesn't use the ICE below 30mph (because that would stall the engine at
its fixed ratio) where the Prius can.

A modified Koenigsegg with ratios adjusted for cruise at the local speed limit
(and a lot less power!) sounds like it would work quite well.

~~~
mywittyname
It's not more complicated; it's less complicated.

The Prius eCVT is just like a traditional planetary gearbox, but instead of
having a complex set of auxiliary gears on clutches which need to be closed in
pairs to vary the speed of the planet gears, thus the output shaft, it uses
electric motors to spin the planetary gears at exactly the speed needed to
obtain the desired output speed.

The Prius CVT is absolutely genius in its simplicity.

Here's a good video on how a traditional planetary automatic operates:
[https://www.youtube.com/watch?v=Ugao6jTyM7k](https://www.youtube.com/watch?v=Ugao6jTyM7k)

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brian-armstrong
There's also a fantastic video where Jay Leno asks Christian Koenigsegg
himself about this transmission and the 7 speed racing transmission

[https://youtu.be/4jhB9Yx0hyY](https://youtu.be/4jhB9Yx0hyY)

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maaark
>It also has a "battery drain mode." Basically, when you are ending your
journey, you will tell the Regera where you will be parking the car, at home
or a charging station. The Regera will then make sure that the battery is
fully drained before it gets to the end point, which means it'll be ready to
accept a charge. Very smart. It has a fully electric mode of about 22 miles.

I thought this was the worst thing you could do to lithium cells?!

~~~
pjc50
"Fully drained" for the system probably doesn't mean "fully drained" at the
cell level, since (as you say) there is a point below which draining cells
damages them. The reported "0%" line will be some way above that.

~~~
maaark
On second thoughts, I'm guessing that what this ACTUALLY does is make sure
that the petrol engine doesn't waste fuel recharging the battery unnecessarily
at the end of the trip when it's going to get plugged in.

~~~
tim333
I like that idea - it means if you are doing less than 22 miles you can run it
as a plug in hybrid and not use fuel. I used to have an old high performance
sports and the fuel use for going down the shops etc was annoying.

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sandworm101
I want to see the dyno chart. Either there are some serious power
spikes/valleys with this setup, or they are nerfing (ie reducing) power at
various points to smooth things. There is no way direct-drive IC engine makes
anywhere near similar power at 100kph as at 200 (double the rmp). This may be
fast, but a transmission would make it much faster.

(A modern trans, at this power/price, would only be 200lbs at most. Less than
carrying a passenger.)

~~~
arghwhat
There shouldn't be any spikes, really. Much less so than with a transmission,
which has peaks for every gear.

The car would basically have the following stages:

1\. All electric. ICE is just powering a generator. 2\. 50km/h+: ICE clutches
in at 1000 RPM. Not much power provided. 3\. 100km/h+: ICE starts delivers at
2000 RPM. 4\. 250km/h+: Peak torque (assuming sweet spot of around 5000 RPM,
just a guess)) 5\. 400km/h+: Redline at 8250 RPM, nothing left.

You'll probably have two torque peaks: Initial electrical acceleration and its
drop-off, and ICE peak and drop-off. Depending on how well-tuned this is, it
might be smooth between those two peaks.

A trans, on the other hand, would have lows, peaks and shift losses between
every gear change, and that's combined with a higher permanent loss.

However, arguably, you could have made a more impressive car while saving
weight: By removing the ICE. You'd probably lose a bit of top speed, but make
up for it in acceleration. 400km/h is useless.

~~~
bluetomcat
Probably a fine setup for optimising straight-line acceleration and 0-400
times, with questionable track performance. A conventional high-performance
car is able to make use of the engine torque at any time by shifting to the
appropriate gear and keeping the engine in a narrow rev-range. This, on the
other hand relies solely on the electric motors to fill that gap before the
torque peak at, say, 250 km/h.

~~~
arghwhat
I'd argue the exact opposite.

A conventional high-performance car will struggle with its lacking
acceleration and narrow optimal rev-range. Every shift is a performance
penalty, and the transmission itself is inefficient. It's only really
acceptable for straight-line 0-400, where the shift range is only gone through
once, and even then it's often too much, with people preferring two-speed
transmissions for drag. For a real race, it becomes extremely wasteful.

The only benefit of a conventional setup is the ability to handle extreme top-
speeds that direct-drive will have difficulty with. However, in most races
you're quite far from 400km/h, making this benefit useless. Instead, you
constantly need immediate acceleration and power from variable speeds, which
an ICE with transmission will always struggle with.

While this particular car is not that impressive performance-wise, it's tuned
for racing, not top-speed. An purely electric racer will run circles around
it, with their only downside being tendencies to battery overheating for
certain races. On that note, see VW's recent pike's peak record:
[https://electrek.co/2018/06/21/vw-all-electric-race-car-
fast...](https://electrek.co/2018/06/21/vw-all-electric-race-car-fastest-time-
in-pikes-peak-qualifying-round/).

~~~
sandworm101
But nobody is saying that conventional is better. They are saying that this
rig could be improved.

~~~
arghwhat
It would appear that someone is suggesting that a conventional transmission
would be an improvement, which I find unlikely.

But yes, it can be massively improved. IIRC, this car is beat in acceleration
by a Tesla Model S P100D, which isn't exactly a supercar.

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iwiririwo
400 km/h

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zepolen
Hey at last, maybe in my lifetime I'll see the motor per wheel AWD design I've
been fathoming for the past ten years.

~~~
cgio
Yes, I've been imagining this too since 25 years ago now, also thinking how it
would not need turning wheels, just power differential like paddling a boat.
Not sure if this part can be done though or if it would break under the
pressure... I should have studied engineering to find out.

~~~
EmbarrassedFuel
This is how tanks steer! And also (to some extent) why using them on roads
ruins the roads. If you tried in a traditionally wheeled car then all of the
drive shafts would snap though!

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ddalex
I used to think that the treads actually ruin the road because it changes to
contact surface on which you apply the power differential from a line (on a
tire) to a rectangle(the tread), i.e. it tries to rotate a flat surface which
can't be rotated, so somethings got to give. Arguably a tire wouldn't have the
same problem.

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bluetomcat
TLDR: At low speeds, such a car is basically an EV with a petrol power
generator and some power control circuitry which chooses to alternate between
charging the battery or powering the electric motor directly. Under heavy
acceleration and after a certain speed threshold (enough for the petrol engine
to utilise the fixed final drive ratio), a clutch is engaged and then
mechanical power is sent directly to the motor, then to the wheels.

~~~
C1sc0cat
Its more like an ICE with electric drive just like some tanks have - the Tiger
I comes to mind.

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aasasd
That's all cool and good, but now I wanna know how you use something hydraulic
for a clutch.

~~~
fsloth
[https://en.wikipedia.org/wiki/Fluid_coupling](https://en.wikipedia.org/wiki/Fluid_coupling)

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aasasd
Thanks! The TLDR seems to be that there's an input turbine and an output
turbine. (I probably should've seen that coming.)

The modern replacement, torque converters, seem to be essentially the same but
with some magical modification of fluid flow in the middle:
[https://en.wikipedia.org/wiki/Torque_converter](https://en.wikipedia.org/wiki/Torque_converter)

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7000skeletons
I think it's pretty telling as to what sort of person I am, that I initially
read the title as "How the 1,500 Hit Point Koenigsegg Regara" rather than "How
the 1,500 Horse Power Koenigsegg Regara".

~~~
akuji1993
Same for me. Too many Pokemon, MMORPG and MOBA games in my life.

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innagadadavida
Anyone here follows rotary hybrids? Mazda apparently is working on one for
2020, but no sports car so far...

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mywittyname
I believe the rotary engine will be relegated to range-extending electricity
generation for an otherwise pure EV in Mazda's setup. Much like the BMW i3 has
a small generator option for longer range.

