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EV Cars

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Re: EV Cars
Post by cthia   » Fri Feb 23, 2018 4:53 pm

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aairfccha wrote:
Imaginos1892 wrote:How about a 40 HP 'pancake' type motor built into each wheel hub? Reduce the whole drive train to four moving parts!


Adding quite a bit of unsprung mass, possibly running into packaging issues because you still need some place to put brakes and you need to keep the motors cooled.

Oh, and they apparently come with a bit of a price tag attached.


The cost may be defrayed in the gas savings minus the cost to charge over the life of the car. There is also the piece of mind of going green, and not dying of CO poisoning. There is also a tax break up to $7500 for going green. Not to mention the piece of mind which comes from no longer being dependent on surviving any future gas wars.


My friend seems to think the two cars would pay for themselves over the four year duration of not having to feed the gas demand of two teenage daughters in college with two gas vehicles. LOL

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Re: EV Cars
Post by Imaginos1892   » Fri Feb 23, 2018 5:44 pm

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aairfccha wrote:
Imaginos1892 wrote:How about a 40 HP 'pancake' type motor built into each wheel hub? Reduce the whole drive train to four moving parts!


Adding quite a bit of unsprung mass, possibly running into packaging issues because you still need some place to put brakes and you need to keep the motors cooled.

Oh, and they apparently come with a bit of a price tag attached.

I don't mean that specific type of pancake motor, I was just referring to the general form-factor of a large diameter proportional to length. They would be electronically-controlled brushless permanent-magnet motors, of course. Brushes are for motors you want to fail.

Unsprung mass would probably be the biggest headache; I suspect they would run at least fifteen kilograms per motor. You might have to mount them near the suspension pivots, attached to the wheels with short, fixed drive shafts. No CV joints to wear out and fall apart.

An electric car doesn't need friction brakes, though the government and insurance companies would probably insist on including them anyway. They would only be used if all four motor controllers failed at once. An electric motor can provide much better, more controlled braking than a clamp grinding against a piece of metal.
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Re: EV Cars
Post by Weird Harold   » Fri Feb 23, 2018 6:55 pm

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Imaginos1892 wrote:Somebody gets it! Mostly, at least.

But a properly designed electric car wouldn't NEED all those drive-train parts. No transmission, no differential, no driveshafts, no universal joints — a hundred and one things that just aren't there to go wrong.


True, but a "Properly Designed Electric Car" is an order of magnitude more expensive to design, gear up to mass produce, and market. The Bolt is designed to be affordable. It doesn't required a computer (or programming) to synchronize four motors, it doesn't require re-tooling the assembly line, or custom parts.

It is in short an interim design to get a foothold in the market and force the construction and distribution of charging stations and acceptance of Electric Cars of any type.
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Re: EV Cars
Post by Imaginos1892   » Sat Feb 24, 2018 1:01 am

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Weird Harold wrote:It doesn't required a computer (or programming) to synchronize four motors

You can get impressively powerful microcontrollers for less than three bucks each in quantity, and the programming only has to be done once. Most of the cost would be in the power conversion components. Four identical motors and controller units per vehicle would help greatly with diluting costs, as would leaving out all those now-useless mechanical parts.

It would take a bigger up-front investment to build a properly designed electric car, but the payoff would be huge. It would disrupt the automotive market, though, in ways the old car companies probably wouldn't like. They're making profits selling the same old cars in the same old way, and don't want to take risks.
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Re: EV Cars
Post by Weird Harold   » Sat Feb 24, 2018 1:25 am

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Imaginos1892 wrote:It would take a bigger up-front investment to build a properly designed electric car, but the payoff would be huge.


Those bigger up-front costs would be more than you think, and recouping them by passing the costs on to the consumers would push your "properly designed" car out of the range of most people.

Cutting every penny out of the design process (and presenting a format people are familiar with) will do far more to spread the use of all-Electric cars than trying to create the perfect electric car straight out of the gate.

Put another way, the Bolt is a "properly designed electric car" for the time and place. Your idea is "the car of the future."
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Re: EV Cars
Post by The E   » Sat Feb 24, 2018 6:03 am

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While praising Musk and Tesla for their design chops and making their cars "the right way", let's not forget that they can be colossal idiots too.

For example, the glove box on some models can only be opened via the touchscreen interface.

Which means that, if you're in an accident which damages said screen, the glove compartment (where most people will keep their driver's license and other things that are useful to have) will be inaccessible.

Musk's reaction to that? "Maybe we'll open the glovebox automatically when the car crashes and make the screen more resilient". Let that sink in. Instead of adding a mechanical latch, Tesla's got to be special and do things electronically that do not need to be.

(Source: http://www.businessinsider.de/elon-musk ... ?r=US&IR=T )
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Re: EV Cars
Post by munroburton   » Sat Feb 24, 2018 9:24 am

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Imaginos1892 wrote:Unsprung mass would probably be the biggest headache; I suspect they would run at least fifteen kilograms per motor. You might have to mount them near the suspension pivots, attached to the wheels with short, fixed drive shafts. No CV joints to wear out and fall apart.

An electric car doesn't need friction brakes, though the government and insurance companies would probably insist on including them anyway. They would only be used if all four motor controllers failed at once. An electric motor can provide much better, more controlled braking than a clamp grinding against a piece of metal.


I'm not sure tossing CV joints are worth it to eliminate something which only needs serviced every five to ten years(climate and working conditions dependent). Even then, what usually happens is the rubber boot is merely replaced and the joint regreased. This usually only happens once, maybe twice, per joint during the average lifetime of a small vehicle. If ever!

Failing to replace these £10-a-pair rubber boots and allowing dirt ingress is what causes CV joints to fall apart so quickly. The true problem is, mechanics hate servicing CV joints(it's a filthy job, even by mechanic standards) and their service advisors would also like to upsell a whole driveshaft instead of a cheap rubber gaiter and a bag of grease. Service managers love it too - replacing a driveshaft requires less labour than proper joint maintenance.

So yes, there are industry-wide scams or practices. But it has almost nothing to do with the cv joints themselves. More to do with the nature of capitalism.
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Re: EV Cars
Post by aairfccha   » Sat Feb 24, 2018 12:32 pm

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cthia wrote:
aairfccha wrote:Adding quite a bit of unsprung mass, possibly running into packaging issues because you still need some place to put brakes and you need to keep the motors cooled.

Oh, and they apparently come with a bit of a price tag attached.


The cost may be defrayed in the gas savings minus the cost to charge over the life of the car. There is also the piece of mind of going green, and not dying of CO poisoning. There is also a tax break up to $7500 for going green. Not to mention the piece of mind which comes from no longer being dependent on surviving any future gas wars.

None of which is an advantage specific to those particular motors.
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Re: EV Cars
Post by Lord Skimper   » Sun Feb 25, 2018 7:13 pm

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The Chevy Bolt EV was designed around the battery pack. It doesn't have a transmission. Not like you think. It doesn't really have a drive train either, it is FWD and has one motor with 1 forward speed and one reverse speed. It is based upon a body style similar to the smaller Hatch that Chevy likes. Spark, Sonic, Spark EV etc... But not the same size of any of them.

The Spark EV was based upon the Spark ICE although it to wasn't the same size.

Chevy Bolt is similar to the Tesla 3, similar price but you can go and buy one today. It is fairly fast but not ludicrous. Has good interior room without being odd. Lots of headroom and legroom. Slightly more range than the Tesla 3. More buttons less screen. Still 10.2 inches and two others. The battery system is more advanced than Tesla's.

Look it up you will be surprised.
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Re: EV Cars
Post by Imaginos1892   » Mon Feb 26, 2018 12:03 am

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If they're using gears to effect reverse, they're even stupider than I thought. Reversing an electric motor is trivial.

Using one motor and a set of differential gears instead of two motors is only slightly less stupid.
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