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Old 03-30-2011, 07:55 PM   #3 (permalink)
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Originally Posted by jamesqf View Post
How about an air hybrid? You'd use a small diesel engine fitted with a Jake brake. Instead of venting the compressed air, you'd store it, and use it later for acceleration.
Don't laugh, Actually this would work for regen, but only at about 10% efficiency which is still better than absolutely nothing. Main problems.
1. Initially regen braking power would be very small and grow as the pressure increased.
2. Once the pressure started increasing you could actually get to a high enough pressure that no more would be stored or possibly cause damage. (I lean toward no more energy would be stored but you would still have brakes)

The limit to the air pressure would be whatever the motors compression ratio happens to be.

This could maybe be used as a cheap low wear instant start stop solution for big motors or a method of reducing the pumping losses from the turbo during the initial takeoff. (it would require variable or controllable timing on the valves though)

Actually, the more I think about it adding start stop to semis would be a great idea and being able to boost enough right after startup that they would never want to smoke wouldn't be a bad thing either.

Not to mention cheap, any existing semi with a jake could be retrofitted in this way. Why add a pump when you already have an excellent 8 piston pump?

Keep the unicorns coming.
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