> From: [email protected] > To: [email protected] > Date: Wed, 25 Dec 2013 08:04:54 -0800 > Subject: Re: [EVDL] VW Bora will have Protean in-wheel motors > > You could design a rear drive system with two large diameter motors and > still retain almost the same efficiency as in-wheel motors. Here's how. > > Use a CV joint in each wheel to allow a flexible connection to a half axel > drive shaft. On the other end of each shaft, mount one of the motors.. > Secure the motors to the chassis with a pivot connection, so that the > motor's angle can change as the wheel goes up and down. > > As I understand it, CV joints run better than 99% efficient. Without having > gear reduction, then, this means your drive train efficiency is 99% * > efficiency of tires. Probably the best you can get. > > The only problem I see with this design is making room for large diameter > motors. I'm not sure of the diameter of experimental in-wheel motors, but > I'll guess somewhere around 10-12". They might need to drop down and be > shielded with something strong (and heavy), or they might need to protrude > up a bit into a trunk space or bed area. Better yet, if the battery is > sandwiched under the floor, that gives a bit of vertical space to better > accommodate large diameter motors. > > One other possibility is to do this with front wheel drive instead. Can > that still be done with one CV joint per side? If so, there is much more > vertical space under the hood and it seems that two large diameter motors > could easily be fit in. Note this could be done with one motor if you add > another pair of CV joints. > > This is getting awfully close to a typical front wheel drive, I think. The > only real difference is the gear reduction. But, hey, if eliminating gear > reduction can save 10%, why not? > > Well, I'm not building this, but I think it would be fascinating to see if > it's possible to make this work and boost the efficiency of the drive train. > > Peri >
Electroengine had direct drive with CV-joints in the SAAB Cabriolet in 2009 (?) Have a look, at the not soo good concept picture here: http://www.electroengine.com/about-us As I remember it back then, the motors was from some Swiss company, maybe Austria: http://www.electroengine.com/true-electric-technology/true-electric-motor https://www.youtube.com/watch?v=GpYICgS3XKI 1400 Nm or so, in 2 wheels/motors combined. I think it was about 200kW in the first prototype. Maybe it was a pack of 40Ah Thunderskys in this video. :-) I am not 100% sure if it was the same E.engine branded-motors in the SAAB 9-3 later, and BostonPower-Swing(?)-cells: https://www.youtube.com/watch?v=qNviw_gnWuA / John -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20131227/727933a0/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)
