View Single Post
Old 05-19-2010, 10:16 AM   #11 (permalink)
bwilson4web
Engineering first
 
bwilson4web's Avatar
 
Join Date: Mar 2009
Location: Huntsville, AL
Posts: 843

17 i3-REx - '14 BMW i3-REx
Last 3: 45.67 mpg (US)

Blue Bob's - '19 Tesla Std Rng Plus
Thanks: 94
Thanked 248 Times in 157 Posts
Quote:
Originally Posted by orange4boy View Post
. . . I've had my NHW11 up to 60mph with no problem.

What I don't understand is that if it was so bad to leave the engine in neutral ICE off over 42 then why didn't Toyota explicitly warn against it or install a warning/error/failsafe?

Where does the prohibition come from?
It was 'folk lore' in "Prius Technical Stuff" when I joined. There is some evidence from the Dept. of Energy studies at Battelle that at high rpm, the induced voltages begin to exceed the traction battery buss voltage. Speculation, at a high enough value the inverter power electronics might lose their dictatorial control of ICE operation because of these high voltages. But so far, no one has 'done the forbidden experiment' and tested to failure. Inducing a failure is not enough, we really need instrumentation so we can understand what happened.

The nominal MG1 speed limits:
  • 6,500 rpm - NHW11, no voltage doubling of the inverter (I've survived ~50 mph in this mode)
  • 10,000 rpm - NHW20, which uses a voltage doubling technique

Bob Wilson

__________________
2019 Tesla Model 3 Std. Range Plus - 215 mi EV
2017 BMW i3-REx - 106 mi EV, 88 mi mid-grade
Retired engineer, Huntsville, AL
  Reply With Quote