Jones, it does not matter how the energy is supplied to the wheels,
directly as in the Prius or through generator- motor combination as in
the Volt. Also, it does not matter what size motor or generator is
used. The engine has to supply enough power to keep the car moving at
normal speed once the batteries have been exhausted. The Volt will
need at least as big an engine as the Prius, depending on its weight.
Ed
On Sep 18, 2008, at 12:10 PM, Jones Beene wrote:
Ed,
Once again - this is comparing apples to oranges.
The current Prius is not really relevant to this market niche, which
can be called the "most efficient and affordable HEV." The Pius is
really in a quasi-luxury niche and its present price indicates this.
The goal is for double the mileage of the Prius. Of course the PHEV
gets infinite "mileage" but that neglects the energy of the grid
power. There is a good balance - which goes beyond what the current
Prius can do, but does not require as long a range as the Volt.
Toyota is moving in this direction already.
Sure - the Prius has a large ICE now -- but that is primarily
because it has an undersized electric motor.
If and when the electric motor is properly sized for hills and for
acceleration BY ITSELF -- then the backup ICE can be much smaller,
since it does not ever power the vehicle directly.- and in fact it
only powers a genset. when the batteries get low. The range on
batteries will be half or less what the PHEV like the Volt must have
and they do not need to lithium.
Since the small ICE can operate at its most efficient rpm range,
regardless of the slower speed of the car, then a smaller ICE is
adequate for this design.
After all - even a 500 cc motorcylce engine can produce 30 kW at its
highest power - which is more than adequate for any hill with a
small hybrid -- when the electric motor itself is correctly sized.
Jones
