5 ms·

Doesn't higher torque directly lower fuel efficiency? It seems they could get better range if they weren't trying to make the car a "blast to drive around town

Doesn't higher torque directly lower fuel efficiency? It seems they could get better range if they weren't trying to make the car a "blast to drive around town". Having a car be a "blast" may be fun for the driver but certainly not anyone else outside the vehicle.

deleted 7y ago
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Tepix 7y ago
I don't know. I heard that stronger electric motors are not much more expensive and they allow more recuperation during breaking which is why they make sense even if you don't want to accelerate like a race car driver.
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nacs 7y ago
This is an electric car so the 'fuel' is batteries. And the article mentions that there is a "Sport" mode that can be activated that would result in the full torque (otherwise it's at a reduced power to reduce battery usage).
FigBug 7y ago
Not really. Efficiency doesn't change much based on torque. See here for Leaf: https://farm5.static.flickr.com/4106/4844105739_3795e703f2_b.jpg https://farm5.static.flickr.com/4106/4844105739_3795e703f2_b... There is very little downside to putting a bigger motor than needed in an EV, other than a bit of extra weight to move around. As long as you don't use that power, (fast acceleration), you won't pay for it. That said, 221 lb-ft of torque isn't very much. They don't say at what rpm that is. Most EVs are electronically torque limited at low rpm. Assuming the peak torque is around 2000 rpm, that's only 84 hp. (My biggest pet peeve is torque without rpm -- it's meaningless!)
- tosser0001 7y ago
  This rant about horsepower here has always stuck with me (and this is an 11 year old article): http://www.espn.com/espn/page2/story?page=easterbrook/080909 http://www.espn.com/espn/page2/story?page=easterbrook/080909 (Unfortunately you need to search for the section "Hold Your Horsepower") I assume the same would apply to electric vehicles. It seems insane to continue the power arms race with cars given the detrimental impact is has.
- ricardobeat 7y ago
  > My biggest pet peeve is torque without rpm In EVs the max torque is available at 0 RPM, so it doesn’t really matter (and the drop off curve will be almost the same for every electric motor).
- deleted 7y ago
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darkwinx 7y ago
I don't think it is about higher torque. It is more about instant torque, which a characteristic of electric motors. AFAIK, they did not design the motor to behave that way, it just the natural behavior of the electric motor.
phkahler 7y ago
>> Doesn't higher torque directly lower fuel efficiency? Short answer: No. Longer answer: For a given flux density, torque is proportional to the rotor volume. To get higher efficiency usually requires adding material (copper) to the windings to lower electrical resistance, which may require a larger diameter motor. Having said that, for a given motor design you are likely to get better range by accelerating at lower torque for a longer time as opposed to more exciting driving. I never understood peoples enthusiasm for torque numbers. It all goes through gears and then gets divided by tire radius to get a forward force, and then gets divided by vehicle weight to get acceleration. Just give us the final acceleration in G's please. Similarly, power is important but power/weight is going to be more indicative of 0-60 time.

deleted 7y ago

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Tepix 7y ago

I don't know. I heard that stronger electric motors are not much more expensive and they allow more recuperation during breaking which is why they make sense even if you don't want to accelerate like a race car driver.

deleted 7y ago

[deleted]

nacs 7y ago

This is an electric car so the 'fuel' is batteries. And the article mentions that there is a "Sport" mode that can be activated that would result in the full torque (otherwise it's at a reduced power to reduce battery usage).

FigBug 7y ago

Not really. Efficiency doesn't change much based on torque. See here for Leaf: https://farm5.static.flickr.com/4106/4844105739_3795e703f2_b.jpg https://farm5.static.flickr.com/4106/4844105739_3795e703f2_b... There is very little downside to putting a bigger motor than needed in an EV, other than a bit of extra weight to move around. As long as you don't use that power, (fast acceleration), you won't pay for it. That said, 221 lb-ft of torque isn't very much. They don't say at what rpm that is. Most EVs are electronically torque limited at low rpm. Assuming the peak torque is around 2000 rpm, that's only 84 hp. (My biggest pet peeve is torque without rpm -- it's meaningless!)

tosser0001 7y ago
This rant about horsepower here has always stuck with me (and this is an 11 year old article): http://www.espn.com/espn/page2/story?page=easterbrook/080909 http://www.espn.com/espn/page2/story?page=easterbrook/080909 (Unfortunately you need to search for the section "Hold Your Horsepower") I assume the same would apply to electric vehicles. It seems insane to continue the power arms race with cars given the detrimental impact is has.
ricardobeat 7y ago
> My biggest pet peeve is torque without rpm In EVs the max torque is available at 0 RPM, so it doesn’t really matter (and the drop off curve will be almost the same for every electric motor).
deleted 7y ago
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darkwinx 7y ago

I don't think it is about higher torque. It is more about instant torque, which a characteristic of electric motors. AFAIK, they did not design the motor to behave that way, it just the natural behavior of the electric motor.

phkahler 7y ago

>> Doesn't higher torque directly lower fuel efficiency? Short answer: No. Longer answer: For a given flux density, torque is proportional to the rotor volume. To get higher efficiency usually requires adding material (copper) to the windings to lower electrical resistance, which may require a larger diameter motor. Having said that, for a given motor design you are likely to get better range by accelerating at lower torque for a longer time as opposed to more exciting driving. I never understood peoples enthusiasm for torque numbers. It all goes through gears and then gets divided by tire radius to get a forward force, and then gets divided by vehicle weight to get acceleration. Just give us the final acceleration in G's please. Similarly, power is important but power/weight is going to be more indicative of 0-60 time.