RUF's electric Porsche breaks cover

Click above for more high-res shots of the eRUF Model A Concept

Rumors of RUF's impending electric Porsche were true, except that the actual vehicle is based on a Porsche 911, not the Cayman as previously reported. Powered by a three-phase electric motor that offers about 200 horsepower along with an impressive 480 lb.-ft. of torque, the eRUF Model A can reportedly hit 60 miles per hour in under seven seconds and can reach a top speed of 160. Power comes from a lithium iron phosphate battery pack, which produces 317-volts and 480-amps and is made up from 96 individual cells. A full charge takes a rather long 10-hours, and regenerative braking is included in the package allowing for a range of up to 180 miles. From the outside, you'd never really know that something was different about this 997, except that it doesn't produce that soul-stirring flat-six sound. This is still just a concept and its specifications are subject to change. We can be sure, though, that this isn't the last electrically-powered sportscar set to hit the market.

[Source: RUF]


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

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

· 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

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