# How does the Koenigsegg Regera work?

The Koenigsegg Regera is Koenigsegg's newest car, and is a hybrid. However, unlike other "hypercars," like the Holy Trinity, the Koenigsegg doesn't have a gearbox. I'm assuming that it uses some sum of motors to get the car moving off the line, and also uses a motor to "spin up" the engine, so it doesn't need a gearbox, but is this how it actually works? How can such a high performance car work without a gearbox? I feel like there's some torque converter in there somewhere...

Well, you have posted the link to the website, where they explain it, and also give this image:

There are three E-motors. Two on the axes, and one on the same shaft as the combustion motor (C-motor), which connects to the axes via a hydraulic coupling and a differential with a ratio of 2.73

Now, let's play with that numbers. The C-motor has its red line at 8250RPM, so it turns the axes at 8250RPM/2.73=3022RPM. The rear wheel dimensions are 345/30 R20 Y, which means they have a circumference of 2.17m. So, at max RPM, the car does 2.17m * 3022RPM = 6558m/min or 393km/h.

They don't state a top speed, but they write something like 20s from 0 to 400km/h. So it is feasible that the C-motor is connected to the axes via a 2.73 ratio differential.

However, the car would drive at 47km/h when the motor is at 1000RPM...

The solution is also written in the text of the website:

Koenigsegg has developed a clutch-slip mechanism that uses the hydraulic coupling to convert torque at medium/high speeds during fast acceleration. This allows the combustion engine to gain revs and power, thereby giving the sensation of a traditional downshift with the associated aural enjoyment, even without the traditional gearbox.

So, the answer to your original question is: They do have a torque converter like most other automatic cars, just a bit bigger / more sophisticated, so it can replace a gearbox.

(And I wonder why the put that third E-motor onto the shaft of the C-motor - a torque converter always steals some power, i.e. fuel/battery. But I guess that doesn't matter here, people are interested in peak performance, not efficiency / endurance)

• I agree with most of what you've said here. The third "E-Machine" on the front of the ICE provides a generator source for the batteries, provides extra torque for the ICE when needed, plus is probably used as a starter for the ICE. All three "E-Machines" can be used for regenerative braking. I'm wondering about the "clutch-slip mechanism" and whether it's actually a torque converter ... but it may just be mumbo-jumbo talk for sales purposes. If it is a TC, it can use a lock-up just like any other TC to stave off power losses at speed. Aug 12, 2016 at 11:29
• @Pᴀᴜʟsᴛᴇʀ2: D'oh, you're so right about the 3rd E-motor! About that clutch-slip mechanism: It seems it works as torque converter at low speed, can lock-up at higher speed, but can also be switched back to "TC-mode" at higher speed for more torque and that "kick-down feeling". Aug 12, 2016 at 12:01
• Are there any other cars that use hybrid technology in this fashion (using a motor on the engine output shaft), or is Koenigsegg the first one? Aug 12, 2016 at 18:12
• @ThePickleTickler the Honda CR-Z is a manual transmission hybrid which does exactly that. Apparently Honda has been making hybrids with the motor coupled to the engine output shaft since 1999 in one flavor or another. Aug 13, 2016 at 15:52