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Lamborghini Unveils a Self-Healing Electric Supercar Concept

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Re: Lamborghini Unveils a Self-Healing Electric Supercar Concept

#71

Post by dsfyu404ed »

retailbuyout wrote: post #70
hwillis wrote: post #59

Earlier quoted context omitted.

A lot more wear- it's seriously nontrivial to make large flexing electrical connectors that will last through the stress cycles of loading and unloading the wheel. It also makes cooling waaaaaay more difficult for high power motors. Liquid is obviously challenging but air is also a huge problem- you run out of space for sinking heat. There's lots of air in that area but it's very, very challenging to prevent it from…

I’m car illiterate. Why is the braking power proportional to the engine rather than mass or drag or something? Or did i misunderstand?

It's a rule of thumb for "normal" cars.

If anything it takes less power to stop just as fast as you accelerate because of this wonderful thing called the atmosphere.

The problem is that stopping as fast as you accelerate is still too slow to be satisfactory in a lot of cases.

On low end cars that don't have enough power to roast the tires at any speed in any gear you need more braking power than engine power because you need to be able to use 100% of available traction to get from 60-0 for obvious "think of the children" reasons.

Nobody cares if your Yaris doesn't have enough engine to use every available bit of traction to get from 0-60.

Basically "you should be able to brake 30% harder than you accelerate" is a good rule of thumb for economy cars.

When you start talking high horsepower to weight ratios or other vehicular "extremes" rules of thumb don't really work.

Re: Lamborghini Unveils a Self-Healing Electric Supercar Concept

#72

Post by chadgeidel »

retailbuyout wrote: post #70
hwillis wrote: post #59

Earlier quoted context omitted.

A lot more wear- it's seriously nontrivial to make large flexing electrical connectors that will last through the stress cycles of loading and unloading the wheel. It also makes cooling waaaaaay more difficult for high power motors. Liquid is obviously challenging but air is also a huge problem- you run out of space for sinking heat. There's lots of air in that area but it's very, very challenging to prevent it from…

I’m car illiterate. Why is the braking power proportional to the engine rather than mass or drag or something? Or did i misunderstand?

Braking power is proportional to mass and velocity. Larger mass moving faster needs bigger brakes.

Electric motors can be used to provide some braking via regeneration, but even so braking generally comes down to "how much heat can you dissipate". A small, slow (relatively speaking) city car won't have as much heat to dissipate, so there are more options when braking.

Re: Lamborghini Unveils a Self-Healing Electric Supercar Concept

#74

Post by mtreis86 »

LeonM wrote: post #6

> the company will develop in-wheel electric motors, which would eliminate the need for a single large engine. A 'single large engine' is only needed in ICE cars, electric vehicles have a 'small' motor, and can easily have multiple motors. It's already being done by Tesla and Rimac. To my knowledge, an 'in wheel' motor would not be desirable due to unsprung mass, so a motor on the chassis connected to the wheel with…

Unsprung weight would make this a terrible car to drive - it would handle like a truck at best. The motors should be mounted where differentials currently go. Four motors, with an axle out from each.

Re: Lamborghini Unveils a Self-Healing Electric Supercar Concept

#75

Post by ghostbrainalpha »

drblast wrote: post #73

This article reads like the cars my friends and I would "design" when we were in third grade. Oh yeah? Mine is gonna have 800 horsepower and will be amphibious and have wings like the batmobile!

Even if you are pointing out this car is more fantasy than reality, I think this anecdote is more telling about the shift in perspective towards electric vehicles.

When children design the Batmobile of the future, it used to feature a rocket launcher. Now it might have a "self-healing" battery.

Before change can happen in reality, what we aspire to, or what we consider desirable has to change.

Re: Lamborghini Unveils a Self-Healing Electric Supercar Concept

#76

Post by roman_savchuk »

johnbrodie wrote: post #67
roman_savchuk wrote: post #34

Earlier quoted context omitted.

Large outrunner motors like Emrax aren't much heavier than typical cast alloy wheels. Assuming wheel-motor eliminates disc brake components (sounds scary, right?) assembly will probably be even lighter. http://emrax.com/products/emrax-268/

At least on a performance vehicle, that's still far too heavy IMO. 40ish lbs? The (cheap) wheels on my Miata are 11 lbs, without any exotic materials or crazy engineering. Almost quadrupling the unsprung mass is a hard sell performance-wise.

Which gen Miata? IIRC NA had something like 5.5x14" wheels which are tiny. But if we look at bigger production car wheels even modest 8x18" could weigh > 30lbs. Second, (unsprung mass/sprung mass) ratio is the thing that counts, not the mass itself. So, while 40 lbs wheel is terrible for the Miata, it might be quite ok for the vehicle twice Miata's weight.

Re: Lamborghini Unveils a Self-Healing Electric Supercar Concept

#77

Post by kiddico »

mperham wrote: post #62
stoev wrote: post #43

Earlier quoted context omitted.

Also, an in-wheel electrict motor would: 1. suffer a lot more from wear and tear than a motor mounted to the chassis. 2. restrain the amount of space available for brakes. While it would be reasonable to say that a small city car could forego its rear brakes and use electric motors instead to deccelerate, coupled with brakes at the front, a four wheel drive supercar with four electric motors would have no chance rely…

> Even electric motorcycles with 30-40 bhp rely on water cooling, let alone a car 20 times the weight. FYI my Zero SR motorcycle, which has 70+hp, uses passive cooling only.

I think you just showed me what my next major purchase will be. Those look awesome!

Re: Lamborghini Unveils a Self-Healing Electric Supercar Concept

#78

Post by BinaryIdiot »

laichzeit0 wrote: post #26

I drive a car with low clearance, but that Lamborghini is just ridiculously close to the ground. You’ll scrape the bumper just pulling out a regular drive way. It sure as hell will need to be “self healing” for someone to legitimately be driving that.

Most of their concepts are like that; I wouldn't expect a model for sale to be that low.

Re: Lamborghini Unveils a Self-Healing Electric Supercar Concept

#79

Post by zone411 »

retailbuyout wrote: post #70
hwillis wrote: post #59

Earlier quoted context omitted.

A lot more wear- it's seriously nontrivial to make large flexing electrical connectors that will last through the stress cycles of loading and unloading the wheel. It also makes cooling waaaaaay more difficult for high power motors. Liquid is obviously challenging but air is also a huge problem- you run out of space for sinking heat. There's lots of air in that area but it's very, very challenging to prevent it from…

I’m car illiterate. Why is the braking power proportional to the engine rather than mass or drag or something? Or did i misunderstand?

I'm not sure if that's what the great parent meant but think about two sports cars on the race track: on every lap at the end of the straights, the better accelerating car will be going faster and therefore need better brakes to slow down to make the next corner.
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