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Boxster E with Four Wheel-Drive
The Boxster E is an
all-electric vehicle without any additional combustion engine on board.
Propulsion is provided by two independent electric motors with constant mesh
gearboxes that act on the front and rear axles. The rear drive unit comprising
motor and transmission, together with the power electronics for controlling the
electric motor is located where the manual transmission and exhaust system are
accommodated in the conventional Boxster. In the front end, the space vacated by
the 64-liter fuel tank, now redundant, is occupied by the second drive unit. The
power electronics unit in the adjacent luggage compartment serves the front axle
electric motor. The Boxster E thereby features all-wheel drive without
mechanical transmission of power. To ensure maximum driving stability and
traction, a central electric control unit looks after the synchronisation of the
two electric motors and controls the drive torque distribution to the front and
rear axle.
The two electric motors develop a total power output of 241 hp
(180 kW) and a maximum total torque of 398 lb-ft (540 Nm) at a maximum engine
speed of approximately 12,000 rpm. That means that the two electric motors in
tandem deliver significantly higher drive power than what is available from
present day hybrid vehicle electric power units. As well as the all-electric
drive of the Boxster E producing zero tailpipe emissions, it also offers a
completely new form of Porsche driving pleasure. Maximum torque of the electric
drive kicks in virtually from the first turn of the engine. The Boxster E moves
almost silently while at the same time developing powerful propulsion from the
very outset.
The two motors enable the two-seater to sprint to 60 mph in
5.3 seconds from a standing start. Its top speed, limited to 124 mph (200 km/h)
is achieved without any gear change at all - whether automatic or manual. The
high power output of the two motors offers a second advantage: it means more
recovered power is available because more energy can be recovered during
braking. This increases efficiency of the drive unit.
Boxster E with
Rear Wheel Drive
In the case of the two other Boxster E models with
rear wheel drive there is no front electric motor, therefore delivering a power
output of 120 hp (90 kW) and a rated torque of 199 lb-ft (270 Nm). This model
can sprint from a standing start to 60 mph in 9.2 seconds, with a top speed of
93 mph (150 km/h).
Active Sound Design
As all Boxster E
models are comparatively quiet on the road, Porsche engineers have designed an
Active Sound Design system that provides drivers with acoustic feedback as well
as alerting pedestrians and other road users.
New Expression of
Porsche Intelligent Performance
Irrespective of variant, the heart of
every Boxster E is manufactured by Porsche. The lithium-iron-phosphate based
traction battery is fitted in place of the combustion engine. Each of its cells
has a nominal voltage of 3.3 V and an individual capacity of 20 Ah. Based on the
NEDC, the combined energy from 440 individual cells is good for approximately
107 miles (170 kilometers) of driving in the Boxster E with its
ready-for-the-road weight of a mere 3527 lbs (1,600 kg).
For an overall
weight of 752 lbs (341 kg), the battery's energy content is 29 kWh of which for
inherent physical reasons approximately 26 kWh are available for use - an
outstanding performance for a battery.
Its maximum power output is 240
kW, or 60 kilowatts more than the all wheel-drive Boxster E draws under full
load. The battery and power unit components are connected to two water cooling
circuits. As with the conventional power unit, the heat exchangers are
accommodated behind the front air intakes.
The battery is anchored to the
same points on the body structure as the combustion engine in the Boxster S.
There are numerous advantages to this, especially in the event of a crash,
because by using the same load paths as in the Boxster S, the battery is
optimally retained within the vehicle while at the same time being protected
from damage by the surrounding body structure thanks to its central position
within the vehicle. As with the combustion engine in the production car, the
traction battery is installed in the Boxster E from below and can be swapped out
very quickly if so required. This is also facilitated by special motor sport
fasteners that enable the battery to be disconnected from the cooling circuit
without air getting into the system.
Charging the Boxster E
The traction battery is charged via a charging cable. Any conventional
socket can be used as an energy source. The charging port on the vehicle
features an illuminated ring and, as with any Porsche sports car, the vehicle is
'refuelled' (in this case, recharged) at the front end. The charger is
accommodated at the front of the car. It converts alternating current from the
socket into direct current, enabling the traction battery to store the electric
energy. Its charging capacity is a maximum of 3.3 kW meaning that it takes
approximately nine hours for a full charge. The charging time can however be
reduced using a rapid charging function. There is enough space left over for
luggage in the front storage compartment despite the electronic components; the
rear luggage compartment of the Boxster E remains unchanged.
Porsche Boxster E Concept: Photo Gallery, Review (1/2) and Specifications