Technology

Air conditioning and touchscreens didn’t alter how cars drove but did revolutionize the driving experience.

Can we please make touchscreens for neccessary functionality illegal, like using phones while driving?

Can we have more mechanical posts like this?

There's 2 significant inaccuracies in the article and 1 large oversight in the official video.

1. Differentials are not one wheel drive. They can seem to drive only one wheel when spinning the wheels as one let's loose and the other stays still, but it's not driving one wheel. It's still driving both. The problem is the free wheel is spinning at twice the speed indicated on the speedometer and the other is at 0. The driveshaft puts in a certain number of turns, the wheels, together, must add up to an equal output (multiplied by the gear ratio). If the car is going straight with full traction, then they turn the same. If you floor it in snow, one is probably spinning 40% over it's share and the other 40% under. This is not unique to rwd either as fwd cars still very much have a functioning differential. To throw some numbers at it to help clarify the function, let's say the engine is asking the wheels to spin at 30rpm each in a straight line. In a left turn, the right wheel travels further and needs to spin at 35rpm while the inner spins at 25rpm. It still adds up to 60rpm, same as a straight line. Mash it in the snow and it might be 60rpm in the left and 0nin the right or 0 in the left and 60 in the left. It could be 5/55, 40/20, or any other combo as long as it totals 60.

PS: differentials are irrelevant when the wheels aren't connected to each other. Individual-motor wheels, as shown in the video, don't need a diff. The non-drive wheels in a 2-wheel drive vehicle do not have a differential on the non-drive axle.

2. Cv joints are not specific to fwd as nearly all modern rwd cars with independent rear suspensions have CV joints. I don't know of any trucks still using U-joints either since big trucks are solid axle. Cv joints function the same as U joints. The difference is C.V. joints output constant velocity whereas U-joints (what you'll see often under trucks on the driveshaft, two square C shaft ends with an X link between) have lopey output that gets worse with greater deflection angle. If you own a u-joint bit for your socket wrench, I invite you to play with it. Instead of a solid pinned X between the U ends, CVs have free-rolling balls that can roll inboard and outboard to maintain the link between the shaft's cup and the wheel's cone.

3. The article is inaccurate but the video ignores this part, so I don't fault The writer. The CV joints are said to be a poor design, yet, it ignores the part where the video reinstalls them at 4:20 and 5:10 for the front wheels. This mechanism does not allow angular deflection between the motor and hub, as it's shown, without a CV joint. Lateral displacement, yes, but not angular - as in it can't steer. This may be an overall improvement by reducing how often it needs to bend (only when steering), but it doesn't eliminate it. And even then, the rear suspension is still designed to change camber as it changes ride height. Camber is the angle of the wheel as measured top to bottom, as in what you see from looking at the wheels from the front of the car. It keeps the wheels flat on the ground as you lean the car in a corner. You may see an overloaded car's rear wheels look like /---\ as viewed from the rear or ---/ when hanging free on a lift.

Look, I'm not an engineer at Hyundai (or even a competitor) but this doesn't quite pass the sniff test. Cool idea for sure, but it smells a little like marketing is clamoring for something edgy to display. Even as displayed, the motors and original reduces were already very compact and in close proximity to the wheels compared to a normal engine. The slightly reduced footprint of this uni wheel and slightly increased friction of a bunch of additional gears makes me think this is a fractional improvement in practice rather than a revolutionary improvement.

Did none of you watch the video? The article is crap, but the video explains it well.

Go back and watch the video, ya old codgers!

What a badly written article, wrongly explaining both the diff and the CV joint. That's not what they do or how they work.

One thing I took from the article is they're trying to sale the idea of having MORE space in a car due to smaller transmission system. In 1 presentation, they show the idea of putting a FUCKING DOUBLE BED IN THE CAR!

I DON'T want MORE space in the SAME sized cars.

I want the SAME space but in SMALLER sized cars.

The space we have now is FINE, and the car sizes are TOO BIG.

STOP MAKING BIGGER CARS!

https://youtu.be/Nd6C0y8xc20

Seems really cool. I will definitely not buy the first model vehicle to use this, though.

The explaination of how differentials work was painfully wrong. An I lost confidence in this author's ability to explain the topic.

The one thing they don't really talk about is how it turns. The animations show vertical movement almost exclusively. At one point in the video there is a far shot showing a car turning and it looks like they actually swivel the entire motor to keep it perpendicular to the wheel which if true is going to pretty heavily limit it's turning angle and radius.

For the lazy people out there: https://www.youtube.com/watch?v=Nd6C0y8xc20

If you're gonna go through all this trouble, why not put motors directly into the wheels? Then you can bypass the drivetrain all together and directly power the wheels.

Not a new idea, military trucks used reduction gear drives in the wheels before WWII. Edit: Portal Gears.

One downside to doing this is adding unsprung weight, which is not a good idea.

And it will still need a CV at the wheel to accommodate suspension travel.

I don't understand how they are going to keep dust and dirt out of it. The point where the drive input goes in has so much movement.