EV's need a Transmission?

[George S. Bower]

EV's don't need no stinkin' transmission. That's the beauty right??

Well,

Development of the concept is underway using Zeroshift’s proprietary gear-shifting system. The new gearbox could enable manufacturers to downsize EVs’ electric motors, keeping them running longer at the medium loads and speeds where peak efficiency of more than 95% is possible.

http://www.greencarcongress.com/2010...0819.html#more

[hamchief]

My old EV had a 3-speed manual transmission (no clutch)

[Jason M. Hendler]

One reason petrol heads dismiss the Tesla Roadster as a sports car is that its single gear forced the designers to optimize low end acceleration at the expense of top speed. A transmission with any significant change of gear ratio would eliminate this short coming and allow the advent of a true electric propulsion supercar.

As it stands, such a car would be 4 wheel drive and store energy in 10 kpsi hydrogen or natural gas tanks and use a fuel cell to convert the energy.

A large battery would kill performance and die quickly at high speeds. Only a fuel cell is viable for supercars.

[wtiger]

Yeah even just a 2 speed transmission would make a pretty big difference; especially with higher performance electrics. You can keep the motor closer to it's sweet spot; which is pretty broad, but not limitless.

I have to agree that super cars aren't best suited for batteries yet they still need gasoline to be at their best, but within the next 20-30 years I wouldn't be surprised if that changed. With the relatively slow progress of fuel cells and all the problems associated with hydrogen, I'll be pleasantly surprised if it's ever the best choice for super cars. Maybe trucking where space isn't at a premium and it's run for a million or more miles over the lifetime of the vehicle. The associated cost, of the fuel cell, and hydrogen storage problems aren't as pronounced.

[Jason M. Hendler]

Yeah even just a 2 speed transmission would make a pretty big difference; especially with higher performance electrics. You can keep the motor closer to it's sweet spot; which is pretty broad, but not limitless.

I have to agree that super cars aren't best suited for batteries yet they still need gasoline to be at their best, but within the next 20-30 years I wouldn't be surprised if that changed. With the relatively slow progress of fuel cells and all the problems associated with hydrogen, I'll be pleasantly surprised if it's ever the best choice for super cars. Maybe trucking where space isn't at a premium and it's run for a million or more miles over the lifetime of the vehicle. The associated cost, of the fuel cell, and hydrogen storage problems aren't as pronounced.

What problems with hydrogen storage? Quantum Technologies has been selling 10 kpsi compression, storage and fuel tanks for a few years now, so it's in the bag. These tanks are very small and appropriate for sports cars and SUV's that need plenty of fuel for acceleration or towing.

[George S. Bower]

As it stands, such a car would store energy in 10 kpsi hydrogen or natural gas tanks and use a fuel cell to convert the energy.
.

Jason,
sometimes I agree with you.
I absolutely LOVE the idea of a fuel cell range extender.
It would be totally silent.

We need one of those JP8 SOFC's Rooster was talking about.

or a PEM on methane would be much better!
JP8 smells.

Or the solid hydrogen carrier they use on the RC car.
Totally trick-no HP tank.

[Rooster]

Jason,
sometimes I agree with you.
I absolutely LOVE the idea of a fuel cell range extender.
It would be totally silent.

We need one of those JP8 SOFC's Rooster was talking about.

or a PEM on methane would be much better!
JP8 smells.

Or the solid hydrogen carrier they use on the RC car.
Totally trick-no HP tank.

Course if you don't like JP-8, military is also using Ultracell's XX55 methanol fuel cell--snake eaters (Special Operations Herm) love them because they deliver so many KWhrs for the weight and are ruggedized. Don't see any potential for automotive application here. ;-)


http://www.ultracellpower.com/assets...01-27-2009.pdf

[hvacman]

Focus, people, focus. Topic - EV TRANSMISSIONS! Please don't morph this into the H2 economy/fuel cell debate again. It could take this thread down like the Hindenburg. Oh, the humanity!

[Rooster]

Focus, people, focus. Topic - EV TRANSMISSIONS! Please don't morph this into the H2 economy/fuel cell debate again. It could take this thread down like the Hindenburg. Oh, the humanity!

Ok, Ok....sorry! ;-)

So do you think the Volt has a single speed tranaxle, or do you think MG2 may drive the wheels via a 2 or 3 speed tranaxle? It does use a modified 2-mode FWD transaxle.

[George S. Bower]

Course if you don't like JP-8, military is also using Ultracell's XX55 methanol fuel cell--snake eaters (Special Operations Herm) love them because they deliver so many KWhrs for the weight and are ruggedized. Don't see any potential for automotive application here. ;-)


http://www.ultracellpower.com/assets...01-27-2009.pdf

Sorry Hvacman.
Rooster,
thx for the post.
really low power density 55watts=3.5 lb (.015 kw/lb)
so for a 2kw genset fuel cell wt=133 lb
2KW Honda genset=46 lb