A Gizmag article has reminded me of an old idea. Of course, regen on a series motor is a dead horse and most of us lighten our flywheels and some eliminate them entirely for performance and efficiency reasons, but with a clutched conversion, there is potential to get a little bit of kinetic energy recovery. First method: as one approaches a stop light, downshift and engage clutch to spin the motor up to high rpm, and then disengage again and keep the pedal pressed until time for takeoff. That way, the clutch actually gets used a bit, and flywheel momentum goes directly into acceleration. As I recall, consensus has held that this is outweighed by the advantages of reducing rotating mass during all other accelerations, not to mention the risk of overspeeding one's motor, plus wear on the throwout bearing and synchros. I do it sometimes with Karmann Eclectric, but it's more of a novelty than a noticeable boost.
Well, a sprag clutch won't work in this 2-way application, but what about an electric clutch like an air conditioning compressor clutch that holds a flywheel on the tailshaft? Then one could engage it only for initial deceleration, disengage for further slowdown and stop, and then re-engage it for acceleration from a stop. A torque sensor could be used to optimize the disengagement point for further acceleration, but it wouldn't be hard to just do manually 'by feel'. The flywheel would freewheel on the tailshaft at all other times. Of course one is trading bearing drag against full-time rotational mass, but the bearing drag will always be less, as the worst case scenario of bearing lockup would only equal a fixed flywheel. Surely this has been attempted before, but in the recent history of series motor energy recovery, I'm only aware of Ben Graves' microbus with the recuperative air conditioning http://www.evalbum.com/popupimg.php?1279 and the laborious attempts with a clutched and belted alternator on an S-10 by Wayne Anderson http://www.waynesev.com/ ; Anyone succeed in such? I even found an engineering thesis in which the student complicated this concept with a CVT, pneumatic clutch and electromechanical controls, but wound up with only about 20% overall 2-way efficiency. https://kb.osu.edu/dspace/bitstream/handle/1811/51847/1/Honors_Thesis_ShengXu.pdf Jay Donnaway -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140317/6743f4ec/attachment.htm> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
