Hybrid Car – More Fun with Less Gas

40 mpg Prius vs 50 mpg European Diesel cars - Page 3

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Posted by perfb on May 7, 2006, 1:38 pm
excellent description, thanks!  Is this tehcnology unique to Toyota,
i.e. patented etc?    How does it compare to Honda's or Ford's approach
to the hybrid design?

have the same advantages of true motor/generator operation and
simplification of the drivetrain, is that right?

Scott wrote:

Posted by Michelle Steiner on May 7, 2006, 3:24 pm
 perfb@yahoo.com wrote:

Ford's approach is so similar that they had to license (some of?)
Toyota's patents to avoid infringement.  From what I understand, Ford
developed it independently, but there was still the infringement issue.

Honda uses a parallel technology (not parallel to Toyota's, but that's
the kind of technology) in which both the engine and electric motor are
running whenever the car is in motion.  (Of course, when the car is
stopped, like at a stop light, the engine is off, just like with the
Toyotas.)  The engine is more powerful, and the electric motor is less
powerful.  It uses a standard transmission; in fact, you can get the
Civic hybrid with a stick shift.

Stop Mad Cowboy Disease:  Impeach the son of a Bush.

Posted by alt.google on May 8, 2006, 2:57 am

hmm -

I can see your desire to make a DISTINCTION to call attention to a
significant technological DIFFERENCE.

But, when it comes to naming things, I think that the rule is that the
owner or maker gets to decide - whether children, or dogs, or

You make an excellent point that the Prius eCVT is materially,
qualitatively, and significantly different from the variable pulley
belt drives.

But think about it.

CVT isn't an acronim for

CVT means Continuously  Variable Transmission.

Perhaps "second generation CVT" would convey more of the wonder of the
new Prius.
But, it is still a transmission.
And, it is still Continuously Variable.

And if Toyota prefers eCVT to "electric differential CVT" or "second
generation CVT", they make it, and they (not you) get to name it.

Though, I have to say that you have helped others understand the
technology better by your refusal to adopt the given name.

Let's give it a "nick name" (people often do that when they don't like
the given name or it doesn't seem appropriate to the object being

Let's call it eDCVT2 - awfully long, but indicates the second
generation and electronic differential.
I don't really care for the "eD" part either...

Posted by Michael Pardee on May 11, 2006, 6:16 am

Toyota calls it a transmission, and they call the assembly a hybrid
transaxle, but I would argue that in the same way a differential in a
rear-drive axle is a transmission. The similarities are greater than the
differences from a functional point of view. A fundamental difference is the
number of ports: a transmission in a conventional sense has one input port
(connected to the transmission) and one output port (connected to the
differential). A transaxle has three ports: one input and two outputs (for
each drive wheel). A differential has one input and two outputs but lacks
the variable ratio capability. The hybrid transaxle has one input, two
input/output (the motor/generators) and two outputs for the wheels. Nothing
ever changes ratios inside... is that a transmission?

I think your term "electronic differential" captures the operation better.


Posted by kari on May 12, 2006, 3:17 am

Wouldn't it be more correct to say that the hybrid transaxle has three
input-output ports? After all, MG1 spins up the ICE before fuel ignition.


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