# Bosch Sees Role for Transmissions in Electric Cars



## major (Apr 4, 2008)

News Bot said:


> Addition of a transmission with multiple gear ratios is seen as improving the efficiency of the car and giving drivers more control.
> 
> More...


Yet a quote from that article contradicts the headline  



> According to Bosch:
> “Electric motors ………… can run in a single gear, without the need for a transmission.”


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## samwichse (Jan 28, 2012)

Was this article algorithmically generated? Because it makes no sense.


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## CrazyAl (May 9, 2011)

major said:


> Yet a quote from that article contradicts the headline


Agree. Perhaps, the article should have explained why adding a transmission will enhance energy efficiency and what the inadequacies of a one gear drivetrain are.


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## PhantomPholly (Aug 20, 2008)

A transmission can be cheaper than a larger motor. That's why a transmission can make sense in econocars - you don't need massive torque to get you up a hill from a standing start when you can gear down.

The writer, unfortunately, was not able to articulate that in simple English...


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## major (Apr 4, 2008)

PhantomPholly said:


> A transmission can be cheaper than a larger motor. That's why a transmission can make *sense* in econocars - you don't need massive torque to get you up a hill from a standing start when you can gear down.


Car companies are very good at making gears and transmissions. Why then have none of them followed your "sensible" theory? I suspect they all have analyzed the tradeoff of transmission versus motor torque and none have seen any sense to use a shifting transmission in a battery powered EV, have they? The fact is that the torque required to accelerate to top speed is sufficient to negotiate starting on those hills without gear changes.


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## PhantomPholly (Aug 20, 2008)

major said:


> Car companies are very good at making gears and transmissions. Why then have none of them followed your "sensible" theory? I suspect they all have analyzed the tradeoff of transmission versus motor torque and none have seen any sense to use a shifting transmission in a battery powered EV, have they? The fact is that the torque required to accelerate to top speed is sufficient to negotiate starting on those hills without gear changes.


I said "can," not "does." I was being charitable to the writer - it is possible that in some circumstance there is an advantage.


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## Karter2 (Nov 17, 2011)

It's not just the heavier motor but the fact that the designers have to come up with a motor than has high torque, wide rpm range, and high efficiency whilst complying with any "packaging" requirements , cost constraints, and manufacturing practicalities etc.
Some of those parameters will undoubtedly be compromised to some extent and the added flexibility of a multispeed transmission may just help reduce the rigid demands that torque, rpm, weight , etc put on the motor design process.
In addition, a high torque, wide rpm, motor would most likely dictate a high current, high voltage, battery pack, reducing the demands on the battery would again free up choices and possibly allow the use of a cheaper "energy" pack, rather than a "power" intensive pack. .?


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