Sunday, March 7, 2010

Range extender : thoughts

Back to cars and technology which are of my very basic interests.

Last day i was in search for what is the difference between a low rpm engine and a high rpm engine. A big of Google search reveled that low rpm engines are very efficient. The problem with them are when they are used in applications which requires higher rpm output the gear design gets complicated. So there is more chances of transmission failures and more complex transmission control is required.

One solution people used in locomotives was the Diesel-electric transmission. The idea was to power electric motors are electric motors are 70+% efficient and run a diesel generator to power the electric motor. This save a lot on transmission design and was efficient because the diesel generator was designed to run and its peak efficiency all times.

As we are now running for series hybrids like Chevy volt. I think this technology may fit to trucks better than cars.

Reasons :
Trucks need better torque and electric motors provide this.
We have more control over electricity and we have more control.
Trucks doesn't need full power all times. They need power when they work. All other times it runs mostly in a commuter mode.

So if a truck is equipped with a range extender EV technology the advantage are
  • Better torque
  • We can use the generator at work sites when we are out of power
  • Can scale on power out put of generators for power required for a work ( ex: can have profiles like commuter, work - light, medium and heavy etc - The idea on the above is replacing transmissions with generating only the power required for a profile and save the energy by running at sweet spots for max efficiency and power outputs.
  • Less complexity in design and less wear and tear.
  • More efficiency as we use only required power for a situation.
  • Can use the most efficient designs ( ex: use low rpms, high efficiency constant rpm / multiple sweet spot designs and in case of electric motors newer designs with multiple on demand windings to get max efficiency and power on demand )
  • As are using electricity as we can make use of the regenerative mechanisms to generate electricity and use them.
  • We can use buffer mechanisms like ultra capacitors to store energy as
a) Store regenerated energy
b) As a supplement energy for peak energy needs.
c) As a buffer to keep energy
d) As an abstraction to cover the start stop nature vehicle application and can use technologies which doesn't have the start stop nature support.

So Lets expect new applications which is based on the range extender applications which are energy efficient.

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