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Price |
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Production |
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Engine |
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Weight |
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Aspiration |
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Torque |
479
lb-ft |
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HP |
204
hp |
HP/Weight |
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HP/Liter |
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1/4 mile |
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0-60 mph |
under 7 seconds |
Top Speed |
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(from Ruf press
release) eRUF Concept Model A 2008 “ Emotion without
Emission”
Ruf Automobile GmbH,
internationally well known manufacturer for high performance
automobiles and the producer of the famous CTR-series is now
introducing the first electrically powered sports car from Germany.
The fundamental ideas
that lead to the development of the eRUF concept vehicle came from
Alois Ruf. The car maker from the Bavarian town of Pfaffenhausen had
a vision of a simple energy transfer concept: his hydroelectric
power plants, which feed 35 million kW hours of electricity annually
into the German electrical network, could also more or less directly
power modern autos. 35 million kWh is enough energy to power one of
the prototypes eRUF as described below for 3500 journeys around the
globe – or 3500 of the cars one time around the world each.
The idea seemed even
more inspiring, as it would be possible for him to connect cars
directly to the emission-free power plants for charging and drive
away on the water-generated power.
The eRUF Model A concept
car is the first prototype to lead the technical development away
from the combustion engine. Actually, for the first time an
electric motor is being used which comes to fitting into the Ruf
model range.
The three-phase AC
motor’s performance easily puts many conventional conbustion engines
to shame. It produces its maximum 650 Nm torque output from 0 rpm
onwards. This power rips into the drive shafts so impressively
during acceleration, that one is immediately reminded of the
extremely powerful Ruf Rt 12
It is actually enough
simply to put the car in 6th gear and press down the accelerator
pedal (an “amp pedal”, not a “gas pedal” in this car!), and drive
off.
The eRUF Model A has
such impressive acceleration that the project goal of 0-100 km/h in
under 7 seconds was achieved.
The maximum power output
is around 204 hp if you translate it into combustion engine terms.
In direct connection to Volt and Ampere the maximum output level of
150 kW is a useful figure.
A short discourse
regarding efficiency might be helpful at this point: a
highly-developed, modern petrol engine uses around 75 percent of the
energy in its tank to heat the engine coolant and exhaust gas and
only 25 to 30 per cent for actual propulsion. A diesel manages to
convert a respectable 35 to 40 percent of its fuel energy into
motion. The permanent magnet electric motor, on the other hand, is a
model of high efficiency: it offers over 80 percent efficiency over
the majority of its power range, extending 90 per cent in the upper
end of its power range.
Ruf engaged CALMOTORS in
Camarillo, California, specialized in the implementation of hybrid
electric and electric only power train designed to combine the
latest generation of lithium-ion batteries with its motor.
Since the 150 kW
electric motor unit is very compact, there is a lot of room for
batteries in the Ruf’s bodywork.
The Axeon
iron-phosphate, lithium-ion batteries currently in use weight 5.6 kg
and deliver 160 Ah each. This means each one could theoretically
deliver 160 amperes of electricity for one hour under normal
temperatures or 1 ampere for 160 hours.
The generation of
batteries available from Axeon represents by no means the end of the
developmental curve. Current performance improvements in battery
technology indicate that end of this improvement spiral is nowhere
near.
The driving current in
the eRUF is regulated by an electric “drive-by-wire” accelerator
pedal. It is not the first electrical accelerator in a Ruf model.
Other Ruf models also provided load control via
potentiometer-pedals, nicely dosed for their powerful engines.
The power and torque
produced by the 3-phase motor can be used to recover just as much
power as it can put out. When coasting, the motor becomes a
generator producing electricity to charge the batteries. The torque
and electrical amperage ratings below are therefore to be understood
as theoretical absolute maximums and minimums.
The 96-cell battery
system is constantly monitored by an intelligent bus system from
Axeon. Each individual cell is coupled with a sensor that sends
critical information on cell temperature and voltage to the central
control system. If irregularities appear during operation, the
system can react within milliseconds to bring the values back in
line, effectively preventing critical lithium-ion overheating
behaviour during charging.
Tech specs for the eRUF model A,
status of September 2008
All data are preliminary
data as specified for the eRUF Model A
Drive Performance
· Acceleration 0-60 mph under 7.0 sec (development target)
· Vmax 160 mph, 225 km/h
· Cw 0.28
· Roll resistance 0.014
· Driving range approximately 250 – 320 km, depending on
performance level
· Specific power pick-up 21 kW / 125 km/h
Vehicle data
· Engine power 150 kW / 204 PS
· Max torque 650 Nm 7 0 rpm
· Weight 1910 kg (preliminary data)
· Battery weight 550 kg
Motor Data
· Max torque + 650 Nm to -650 Nm
· Power + 150 kW to -150 kW (peak level)
+ 204 hp to -204 hp
100 kW / 136 hp
continuous
· Currency 300 – 420 Volt
· Current level max 550 A
· Rpm level max 5000 rpm
· Operating system brushless three phase alternating current
with permanent magnets
Dimensions
· Diameter 405 mm
· Length 241 mm
· Weight 91 kg
· Specific weight 1,65 kW / kg, 2,25 hp / kg
· Coolant flow 8 L /min max
Battery System
· Type Lithium-Ion, iron-phosphate base
· Manufacturer Axeon plc, GB
· Stored Energy (96 units) 50,72 kWh
· Nominal Voltage 317 Volt
· Maximum discharge 480 A
· Max Power 152,16 kW = 210 PS
· Charging current, max. 16 A
· Charging time 10 hours
Single Battery
Cell Data
· Capacity 160 Ah
· Operating voltage 4,25 V charging, 2,5 Volt discharging
· Nominal Voltage 3,3 Volt
· Max. Temperature Level 80 °C
· Life cycle 3000 charging cycles
· Self-discharge under 3 % per month
· Weight per Unit 5,6 kg
Power-Diagram Efficiency / Engine Speed x 10
