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Brake For Hybrid Vehicles
Tuesday,
October 24, 2006
Last week I
read a press
release regarding the by-wire braking system that
Siemens plans to put into production before the end of
this decade, and I wondered how such a system would work
with the regenerative braking systems of hybrid
vehicles.
Now Siemens isn't really developing the by-wire braking
system for hybrids, but for all automobiles. In fact,
Siemens has far bigger plans than revolutionary brakes.
Siemens is thinking revolutionary drive trains - the
drive-by-wire system.
"Siemens VDO is developing the technology in response
to the increasingly strict emissions regulations, rising
fuel prices and the demand for improved flexibility,"
said Siemens VDO Board of Director Dr. Klaus Egger.
"We consider the electric motor to be the actual
long-term drive solution for fulfilling even the most
stringent emission laws in the future, as opposed to
hybrid drives, which represent an interim solution on the
road to future propulsion technologies." (more)
Now, I don't agree that hybrid technology is necessarily
"an interim solution" because hydrogen fuel cell
hybrid vehicles could be the next evolution of hybrid
vehicles. Such technology might make far better sense for
some or all forms of transportation than fully electric
vehicles. More important, however, I believe hybrid
vehicles can help lay the foundation for both all electric
vehicles and/or fuel cell vehicles while ending foreign
oil dependency and cleaning the environment in the
interim.
Consequently, could drive-by-wire systems, such as by-wire
braking, help hybrids in this evolution towards zero
emissions and zero oil dependency? Or, would by-wire
braking reduce the effectiveness of regenerative breaking
- an important aspect of the hybrid powertrain?
According to Siemens, "In our opinion brake by-wire
systems can easily and ideally be combined with
regenerative braking on hybrid vehicles. This is due to
the fact that electrical brake by-wire systems provide an
ideal interface to split the overall braking demand by the
driver into two channels," Silvia Wolf of Siemens
told me.
"Using brake by-wire systems makes it possible to
realize a very smooth transition between the friction
brake and the regenerative brake so that the driver does
not feel any negative feedback compared to the known pedal
feedback of conventional hydraulic braking systems.
Moreover brake by-wire systems do not need any additional
hardware components to implement the brake blending
feature which is different to hydraulic braking systems
for which additional measures concerning pedal feedback
and safety backup layers are required."
"Thus brake by-wire systems represent the ideal
braking systems to be combined with regenerative braking
and hybrid vehicles, providing best effectiveness of
regenerative braking."
posted by Dahcredyns at 6:46
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