Ruf Automobile GmbH, internationally well
known manufacturer for high performance automobiles is now introducing
the first electrically powered sports car from Germany.
For the first time an electric motor is being used which comes
to fitting into the Ruf
The three-phase AC motor's performance easily puts many conventional
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
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
A short discourse regarding efficiency might be helpful at this point: a
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
Since the 150 kW electric motor unit is very compact, there is a lot of
room for batteries in the
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.
Tech specs for the eRUF model A, status of September 2008.
All data are preliminary data as specified for the eRUF Model A:
∑ 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 Ė 320 km, depending on
∑ Specific power pick-up 21 kW / 125 km/h
∑ Engine power 150 kW / 204 PS
∑ Max torque 650 Nm 7 0 rpm
∑ Weight 1910 kg (preliminary data)
∑ Battery weight 550 kg
∑ 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 Ė 420 Volt
∑ Current level max 550 A
∑ Rpm level max 5000 rpm
∑ Operating system brushless three phase alternating current with
∑ 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