only a new car, but take into account its
safety levels, such as the fireproofing of
the battery box, you’ve got to test so
many different new parts for safety that
it’s a completely different story.
“The first car is like an open book. We
had a very good collaboration with the FIA
to write the regulations, and now we will
have to show them the results. It was very
important to have such good collaboration
to make this project happen.”
Formula E turned to McLaren Electronic
Systems, provider of ECUs in F1, NASCAR
and IndyCar, for its expertise in this
department. Not only will it supply the
electronic brains of the car, but also the
electric motor and gearbox.
The actual powerplant is much smaller
than an internal combustion engine, the
main motor weighing in at just 26kg
(57lb), and its ancillary motor control unit
a further 16kg (35lb). How the motor
functions is all fairly standard, but MES
managing director Peter van Manen
notes that, “The interesting part was the
requirement of a lightweight and compact
powertrain. We’d just developed one of
those for a P1 sports car, so there was
serendipity when Formula E came along.
We had just the right powertrain to
supply their racing application.”
Unlike KERS, where a reasonably high
amount of power is released over a small
amount of time, key to the continuous use
of the Formula E car’s motor will be cooling.
“With KERS, there’s a lot of time where
it’s not being used and can cool down,”
says van Manen. “Whereas here, it’s
another magnitude of difficulty. We have
to get the heat out of the motor as its
working, or the whole thing will melt.”
That means water-cooling systems for the
motor and control unit, but the requirement
is less than for a conventional open-wheel
racecar, so the radiators are relatively small.
McLaren is also responsible for the
transmission, which will have to carry
unusual loads due to the instant torque
demands of electric motors.
“The main difference between an
electric motor and an internal combustion
engine is that everything happens much
more quickly,” says van Manen. “You’ve
got instant torque and instant engine
braking, which is exciting for the racing.
But in terms of the transmission, you have
to deal with the fact you’ve got instant
torque and instant engine braking!
“The transient loading on the gearbox has
to be managed, and we’ve been running
on the dyno all summer to prove it’s
working. It’s a reasonably straightforward,
four-speed sequential gearbox.”
All very exciting for any electric motor
fans. But as someone who likes their
racecars noisy, what will it sound like?
“The intention is to produce natural
noise,” says van Manen. “It’ll be quieter than
an F1 car, but much noisier than a road car,
because the motor’s turning at a very high
speed. I’ve only heard it on the dyno; I think
it sounds quite cool! Electric motors have a
characteristic sound, and you’ll be able to
hear the gear changes, but because the
ambient noise is less than normal racecars
you’ll hear a little more tire noise.”
THE POWER SOURCE
To deliver the required electrical power
over a full stint, the beating heart of the
On the outside, the Spark-Renault SRT_01E
looks remarkably “normal” – that’s because the
battery and electric motor sits where the engine
and fuel tank are on a fossil-fueled racecar.
Sidepod-mounted radiators for cooling the motor
add to the conventional look. Of course, under
the skin, it’s a whole different beast...