4 ms·

I hate the idea of a fake engine noise, but I drive a manual transmission and I know I use my ears a lot to know when to shift.

scroy 12y ago
From what I've read, that wouldn't be relevant for an electric vehicle, since there is no transmission. Or that might only be for the Tesla.
- zyxley 12y ago
  Literally the entire reason for the transmission for a combustion engine is to make the relatively high minimum speed of an internal combustion work for lower road speeds, with the pleasant side effect of increasing torque at low speed. Electric motors have no need for one, because they have both variable speeds and generally tremendous amounts of torque to start with.
  - Gracana 12y ago
    Electric motors tend to have wide useable rpm ranges, but their efficiency varies across the range, so a transmission is still useful. Scroll 2/3 of the way down this page to see a representative brushless DC motor performance curve, for example: http://www.johnsonelectric.com/en/resources-for-engineers/automotive-applications/motion-technology/ec-motor-brushless.html http://www.johnsonelectric.com/en/resources-for-engineers/au...
    - mikeash 12y ago
      AC induction motors (typically what's used in electric cars) have a pretty flat efficiency curve. For example: http://powerelectronics.com/motion-systems/motors-efficiency-and-adjustable-speed-drives http://powerelectronics.com/motion-systems/motors-efficiency... There would be some minor efficiency gains from having multiple gears, but it's probably small enough that it would be hard to overcome the extra losses from having a more complex transmission. Note that technically electric cars do have a transmission. The motor wants to spin much faster than the tires, so you want a reduction gear to let them both live in the ranges where they're happy. It's a single-gear transmission, though, on every electric car I'm aware of.
NovaS1X 12y ago
This is a very good point. I do the same.
grecy 12y ago
Me too, though I just bought a new (to me) 2007 Jeep Wrangler Unlimited Rubicon. It's by far the newest, smoothest, quietest vehicle I've ever owned. So much so, it's actually taking me a long time to get used to when I need to change gears because I can't hear or feel what the engine is doing. Often I look at the tacho and am I bit surprised to see it's either revving way lower or higher than I was thinking. Being a 6-speed and geared very differently that other vehicles it's also tricking me up in terms of engine speed vs. road speed. I drove my last 5-speed 2000 Jeep Wrangler from Alaska to Argentina, and I've owned a stack of stick-shift vehicles before, so it's not like I'm new to this. I'm sure I'll get the hang of it, sooner or later.

scroy 12y ago

From what I've read, that wouldn't be relevant for an electric vehicle, since there is no transmission. Or that might only be for the Tesla.

zyxley 12y ago
Literally the entire reason for the transmission for a combustion engine is to make the relatively high minimum speed of an internal combustion work for lower road speeds, with the pleasant side effect of increasing torque at low speed. Electric motors have no need for one, because they have both variable speeds and generally tremendous amounts of torque to start with.
- Gracana 12y ago
  Electric motors tend to have wide useable rpm ranges, but their efficiency varies across the range, so a transmission is still useful. Scroll 2/3 of the way down this page to see a representative brushless DC motor performance curve, for example: http://www.johnsonelectric.com/en/resources-for-engineers/automotive-applications/motion-technology/ec-motor-brushless.html http://www.johnsonelectric.com/en/resources-for-engineers/au...
  - mikeash 12y ago
    AC induction motors (typically what's used in electric cars) have a pretty flat efficiency curve. For example: http://powerelectronics.com/motion-systems/motors-efficiency-and-adjustable-speed-drives http://powerelectronics.com/motion-systems/motors-efficiency... There would be some minor efficiency gains from having multiple gears, but it's probably small enough that it would be hard to overcome the extra losses from having a more complex transmission. Note that technically electric cars do have a transmission. The motor wants to spin much faster than the tires, so you want a reduction gear to let them both live in the ranges where they're happy. It's a single-gear transmission, though, on every electric car I'm aware of.

NovaS1X 12y ago

This is a very good point. I do the same.

grecy 12y ago

Me too, though I just bought a new (to me) 2007 Jeep Wrangler Unlimited Rubicon. It's by far the newest, smoothest, quietest vehicle I've ever owned. So much so, it's actually taking me a long time to get used to when I need to change gears because I can't hear or feel what the engine is doing. Often I look at the tacho and am I bit surprised to see it's either revving way lower or higher than I was thinking. Being a 6-speed and geared very differently that other vehicles it's also tricking me up in terms of engine speed vs. road speed. I drove my last 5-speed 2000 Jeep Wrangler from Alaska to Argentina, and I've owned a stack of stick-shift vehicles before, so it's not like I'm new to this. I'm sure I'll get the hang of it, sooner or later.