> > >First, what rubbing surfaces in a syncromesh? Syncromesh is engaged or >not, with a transition of sliding lasting perhaps a few hundred >milliseconds. > <Sigh> I didn't say the sliding was in the syncro's . Metal sliding on metal is an inherent property of syncromesh transmissions. You said it yourself;" all forward gears in mesh all the time"....think about it.
> >Second, in a traction AC drive you are limited in how low you can gear. >At 13:1, a likely first gear (VW golfs came with 12.7 to 14.5 for first >gear depending on engine), the motor has to hit about 13,000 rpm for >highyway speeds, assuming a 22.8" wheel, > Ok so it's not exactly the same as first gear on your vehicle, call it first and half (more than first, less then second) -snip- > >All my texts say 98% efficiency for helically cut gears, 99% for spur >cut. Which isn't that much for loss. If you picked up 2% by shuttling >around on the efficiency map for the AC motor (which is very doable) >then you could at least break even. And as a bonus, multispeed manual >gearboxes are quite common, unlike single speed. > Well thanks for proving my point. According to you a single reduction transmission would be about 98% efficient, whereas MEASURED efficiency on multispeed manual transmissions is around 90% give or take a percent or two. Actually 98% for helically cut gears assumes a ratio of 3:1 or less. Higher ratios tend to have slightly more loss.
