an energy recovery level (8MJ max.; 2MJ
min.), and then massaging the specific
balance between engine displacement and
energy recovery system (ERS) oomph is
open to individual interpretation.
Go the route of a bigger engine and you
pay the price with more frequent stops for
fuel. Opt for something smaller, and you
overcome the power deficit by saving time
with fewer trips to pit lane. On the surface,
this could have been a minefield for
manufacturers – a set of rules demanding
a sacrifice of speed or economy, yet the
formula allows efficiency to be increased
without surrendering performance.
Motivated by the liberal LMP1-H
rulebook, the three marques set off in
three very different directions, choosing
engine architectures and hybrid power
levels that prescribe to unique ideologies.
Toyota put its faith in a 6MJ super
capacitor ERS system mated to a growling
3.7-liter, naturally-aspirated V8 that
combine to rattle the earth with 1,000hp.
The TS040 HYBRID is an engineering
marvel, yet packs a punch as subtle as an
earthquake. Wins at the first two six-hour
rounds and pole at Le Mans spoke volumes
about the German-built machine.
Audi’s pioneering nature was diverted
from the engine bay to material sciences.
The R18 e-tron quattro is a technical
masterpiece, its 4-liter, turbodiesel V6 and
flywheel-based ERS system were thoroughly
optimized, and with the smallest 2MJ hybrid
solution in the series, the German brand also
made a statement on where its interests lie.
Porsche, meanwhile, channeled Star
Wars and quirky Swedish automobiles for
its return to prototype sports car racing.
Reprising a 40-year-old engine layout
last seen in the Saab Sonnet, the most
famous name in endurance racing married
a brand-new 2-liter, turbo V4 to a 6MJ
flywheel ERS unit. Impossibly short and
light, the V4 engine is complemented by a
featherweight chassis and running gear –
it’s the waifish supermodel in the paddock.
While all LMP1-H cars feature electric
motors driving the front wheels, only
Porsche chose a secondary exhaust-driven
ERS system to spread the recovery load.
Of the three, Porsche took the task of
total vehicle efficiency to the extreme, while
their rivals embraced a Texas-sized appetite
for brute force through mechanical or
electrical means. Those seemingly random
choices are a byproduct of science, math
and philosophy, and reveal firmly held – and
opposing – views on the right path to follow.
At one extreme, if you want to get an
earful on whether hybrid systems belong
in racing, just ask Audi Sport engine guru
Ullrich Baretzky about how the R18
ended up with the smallest 2MJ system...
“If you look at the big hybrid systems,
the combustion engine in the same time
per lap is producing 140MJ of energy,” he
says. “Compared to the 100kg [220lb] of
weight the hybrid unit adds, making 6MJ
has a marginal effect on the car. So you are
carrying an enormous weight for the dream
to save energy, but you waste 10 times
more. This is not the path to efficiency. This
is the wrong way to go and I’m absolutely
against it from the very first day.”
At the other end of the spectrum, and in
sync with the Japanese giant’s class-leading
Prius hybrid road car, Toyota aimed for
the maximum MJ figure it could capture.
“We went for 6MJ because this is
energy that would otherwise be lost, and
as soon as we can harvest this energy and
convert it, it’s pure power gain,” says Toyota
Racing technical director Pascal Vasselon.
“6MJ option with kinetic energy recovery
is absolutely right – the most efficient.”
Toyota’s decision to stick with a V8
during the new ultra-efficiency era was
indeed a surprise; something small and
turbocharged would seem to be a better fit
“This is energy that would
otherwise be lost. as soon as
we can harvest and convert
it, it’s pure power gain”