Cooley On Cars
Road to the future: Understanding Koenigsegg's Direct Drive systemSwedish car maker Koenigsegg envisions a drive system without a multigear transmission. Brian Cooley explains how the technology works.
[MUSIC] Your typical combustion engine passenger car has always put its power out through a transmission. Either a three, five, seven, nine, today even a ten speed gear box. The reason that gear box is in there is because your engine's got a relatively narrow range of RPM. And sweet spot for power. Yet your car runs at a wide range of speeds and offers different load requirements. So you broker the difference with a wider range of gears. But the overall problem with trans. Transmissions as amazing as they've become is that they remain a crutch. Ideally, you'd rather not have one for three very good reasons. First of all transmissions tend to be heavy and complex. They're one of the most elaborate things in the modern car. Secondly, they're expensive. Largely, as a result of being heavy and complex, expensive to put in, expensive to fix. That's on you. And, of course, they tend to introduce some slop. And some slow gear changes. Now, that's been improved a lot lately. But wouldn't it be nice to take all this out? So Koenigsegg says we can do that because of two interesting trends in powertrains. One, we have higher RPM high-performance engines, and turbos give them better lower. And grunt. Secondly, we have very torque-y electric motors that are quite well proven these days. Electric motors have all their torque from zero on up, and can span at a wide range of RPM. Put it all together here, and maybe, your power train has a wide enough range of RPM. And abilities to deliver power, but it doesn't need gears to help it. [MUSIC] Let's take a look at how they lay that out. Here's the spine of the car. You can see you've got a vertical battery pack up. In between the seats basically. That brings you down to the turbo charged gas engine which has an electric motor on the back side turning the crank when it needs to. Two more electric motors are back here that go out to your drive shaft, to your back wheels. And in the middle there is a fluid coupler and a final drive. [MUSIC] Here's how that looks in a schematic, this fluid coupler and final drive do two important things. If you didn't have that, you'd have basically the automotive equivalent of a fixy, a fixed gear machine. And that's not really useful in a practical world. And then you do have a gear box of. Source, a reduction gear. It's a single speed transmission that never changes, so it's very simple. It's basically a three to one running acc engine. Can run at the higher RPMs which is its sweetspot without having to drive the car at like 60 to 180 miles an hour all the time. Now I'm not saying this is the be-on, end-all of future drive trains, we may never see this again. But it does underline two important trends. Engines that have more grunt because of augmented intakes from turbos and superchargers, and electric motors that can pick up the slack where gas engines don't do so well. Put it all together, you've got a spectrum of power that maybe doesn't need to change gears one day. [MUSIC]