acceleration advantage for electric drive?
acceleration advantage for electric drive?
(OP)
A colleague of mine says an electric motor driving a vehicle has an inherent advantage in accelerating the vehicle. I'm trying to figure out why. I'd think the rotational inertia of the electric motor is comparable to the rotational inertia of the internal combustion motor. If you're going from 0 to 60 mph in first gear, who wins?





RE: acceleration advantage for electric drive?
Javier
RE: acceleration advantage for electric drive?
Bear in mind that the referred rotational inertia depends on the gear ratio ^2, so an IC engine is quite a significant proportion of the inertia of the vehicle in first gear, which has an overall gear ratio of 10.
A direct coupled electric motor (ie wheel motor) might well come out ahead.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: acceleration advantage for electric drive?
RE: acceleration advantage for electric drive?
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: acceleration advantage for electric drive?
RE: acceleration advantage for electric drive?
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: acceleration advantage for electric drive?
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RE: acceleration advantage for electric drive?
But there are certainly a lot of other considerations. I hadn't considered the reflected inertia due to the gear reduction. I think IC engines have a much better power to weight ratio - but then you add the gear box. Somebody out there must have written a paper on this.
My standby response is that if something is clearly better then the car companies would already have adopted it. With electric motors, though, there are so many other issues (environmental, controls, batteries).
Maybe we need a race!
RE: acceleration advantage for electric drive?
RE: acceleration advantage for electric drive?
Once you are moving and you want to accelerate, you drop to a lower gear, jump up the torque curve of the engine and take off.
RE: acceleration advantage for electric drive?
Sounds like you're saying that an electric motor would be a better choice for a drag racer. If so, then why aren't electric motors used for powering drag racers?
RE: acceleration advantage for electric drive?
Why don't you go read the definitions of torque and power.
They are kind of related to each other.
You could also Google search this site to get the previous input of some competent engineers.
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: acceleration advantage for electric drive?
who holds the world record for somes classes of dragsters?
go to http://www.nedra.com/
PS I'm competent and I play with rice burners at home, anyone can get 327 HP from a 327 V8, try it with a 152 CI 4 sometime.
RE: acceleration advantage for electric drive?
RE: acceleration advantage for electric drive?
0 to 60 in under 4 seconds, 248 HP motor, 2500 lb car Oh- and stock.
Can any IC engine car made in the US do this? My 2zzge toyota in an 1800 lb car is almost there.
take a look at this
http://www.teslamotors.com/index.php?js_enabled=1
RE: acceleration advantage for electric drive?
If you include storage, speed control and motors, the cost per hp is very high compared to IC.
RE: acceleration advantage for electric drive?
I'll trow in 2 cents more, a hybred has more available torque than its non-electric brother, but remember, it also carries a few hundred pounds of baggage in batteries and the motor itsself. That said, driving a hybred across Kansas, the hybred will get lower gas mileage.
RE: acceleration advantage for electric drive?