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Image credits: © Porsche.
Press Release
A unique combination of performance and efficiency
Stuttgart. The 918 Spyder embodies the essence of the
Porsche idea: it combines pedigree motor racing technology with
excellent everyday utility, and maximum performance with minimum
consumption. The task faced by the development team was to create the
super sports car for the next decade with a highly efficient and
powerful hybrid drive. Developing the car from scratch, appropriately
beginning with a sheet of white paper, allowed the team to come up with a
no-compromise concept. The entire car was designed around the hybrid
drive. The 918 Spyder therefore demonstrates the potential of the hybrid
drive to a degree never seen before: the parallel improvement of both
efficiency and performance without one being at the cost of the other.
This is the idea that has made the Porsche 911 the most successful
sports car in the world for 50 years. In short, the 918 Spyder will act
as the gene pool for the Porsche sports cars of the future.
The 918 Spyder reveals its close links to motorsport in a variety of
ways. It has been designed, developed and produced by Porsche engineers
who build race cars, in cooperation with series production specialists. A
great deal of insight gained from the development of Porsche race cars
for the 24 hours race in Le Mans in 2014 is thus integrated into the 918
Spyder – and vice versa. The structural concept of the 918 Spyder with a
rolling chassis as its basis – a basic vehicle that can be driven even
without a body – is race car tradition at Porsche. The concept of the V8
engine originates from the LMP2 RS Spyder race car. The load-bearing
structures, the monocoque and subframe, are made of carbon fibre
reinforced polymer. Porsche has many years of experience with this
high-strength, lightweight construction material and has again achieved
top results with the development of the series production 918 Spyder.
Many parts of the super sports car come from manufacturers who have a
proven record as suppliers for motorsport vehicles.
Hybrid drive brings advantages in terms of driving dynamics
A key message of the 918 Spyder is that the hybrid drive from Porsche
is a plus for no-compromise driving dynamics. Drivers can experience
this thanks to the unique all-wheel drive concept with a combination of
combustion engine and electric motor on the rear axle and the second
electric motor on the front axle. It is based on knowledge gained by
Porsche during motor races with the successful 911 GT3 R Hybrid. Due to
the additional, individually controllable front drive, new driving
strategies for extremely high, safe cornering speeds can be implemented,
especially for bends. Furthermore, the advanced “boost" strategy
manages the energy of the electric drive so intelligently that, for
every sprint with maximum acceleration, the full power of the 918 Spyder
can be tapped into by simply pressing the accelerator down fully. In
short, the 918 Spyder allows even drivers without motorsport training to
experience the potential of advanced longitudinal and transverse
dynamics.
The Porsche 918 Spyder also has the potential to break many records.
The current lap time for the North Loop of the Nürburgring is 7:14
minutes. This time was achieved in the presence of international
journalists during test drives in September 2012 – more than a year
before start of production. The 918 Spyder prototype was therefore
approximately 20 seconds quicker than the Porsche Carrera GT. More test
drives on the Nürburgring North Loop will follow. An even more important
factor is that the 918 Spyder surpasses previous models and competitors
by far in its efficiency as well. As a plug-in hybrid vehicle, it
systematically combines the dynamic performance of a racing machine with
over 880 hp and low NEDC fuel consumption, which at about three litres
fuel per 100 km is better than that of most small cars today. To sum it
up: maximum driving fun with minimal fuel consumption.
Carbon monocoque guarantees lightweight design with a low centre of gravity
The 918 Spyder utilizes the best state-of-the-art technologies, taken
straight from motor racing, to achieve its top performance. The entire
load-bearing structure is made of carbon fibre reinforced polymer (CFRP)
for extreme torsional rigidity. Additional crash elements at the front
and rear absorb and reduce the energy of a collision. The car’s unladen
weight of approximately 1,640 kg (“Weissach" package), an excellent low
weight for a hybrid vehicle of this performance class, is largely
attributable to this concept. The drivetrain components and all
components weighing over 50 kg are located as low and as centrally as
possible within the vehicle. This results in a slightly rear end biased
axle load distribution of 57 per cent on the rear axle and 43 per cent
on the front axle, combined with an extremely low centre of gravity at
approximately the height of the wheel hubs, which is ideal for driving
dynamics. The central and low position of the traction battery directly
behind the driver not only supports efforts to concentrate masses and
lower the centre of gravity; it also provides the best temperature
conditions for optimum battery power capacity.
Chassis with race car genes and rear-axle steering
The multi-link chassis of the Porsche 918 Spyder is inspired by
motorsport design, complemented by additional systems such as the PASM
adaptive shock-absorber system and rear-axle steering. Basically, this
incorporates an electro-mechanical adjustment system at each rear wheel.
The adjustment is speed-sensitive and executes steering angles of up to
three degrees in each direction. The rear axle can therefore be steered
in the same direction as the front wheels or in opposition to them. At
low speeds, the system steers the rear wheels in a direction opposite to
that of the front wheels. This makes cornering even more direct, faster
and more precise, and it reduces the turning circle. At higher speeds,
the system steers the rear wheels in the same direction as the front
wheels. This significantly improves the stability of the rear end when
changing lanes quickly. The result is very secure and stable handling.
Porsche Active Aerodynamic (PAA) for different driving modes
Porsche Active Aerodynamic (PAA), a system of adjustable aerodynamic
elements, ensures unique and variable aerodynamics; its layout is
automatically varied over three modes ranging from optimal efficiency to
maximum downforce and is tuned to the operating modes of the hybrid
drive system. In “Race" mode, the retractable rear wing is set to a
steep angle to generate high downforce at the rear axle. The spoiler
positioned between the two wing supports near the trailing edge of the
airflow also extends. In addition, two adjustable air flaps are opened
in the underfloor in front of the front axle, and they direct a portion
of the air into the diffuser channels of the underbody structure. This
also produces a “ground effect" at the front axle.
In “Sport" mode, the aerodynamic control system reduces the attack
angle of the rear wing somewhat, which enables a higher top speed. The
spoiler remains extended. The aerodynamic flaps in the underfloor area
close, which also reduces aerodynamic drag and increases attainable
vehicle speeds. In “E" mode, the control is configured entirely for low
aerodynamic drag; the rear wing and spoiler are retracted and the
underfloor flaps are closed.
Adjustable air inlets under the main headlights round off the
adaptive aerodynamic system. When the vehicle is stationary and in
“Race" and “Sport" mode, they are opened for maximum cooling air intake.
In “E-Power" and “Hybrid" modes, they close immediately after the car
is driven off in order to keep aerodynamic drag to a minimum. They are
not opened until the car reaches speeds of approximately 130 km/h or
when cooling requirements are higher.
From comfortable to race-ready: five modes for three motors
The core of the 918 Spyder concept is its distribution of propulsive
power among the three power units; their cooperation is controlled by an
intelligent management system. To best exploit these different
approaches, the Porsche developers defined five operating modes that can
be activated via a “map switch" on the steering wheel, just like in
motorsport cars. On the basis of this pre-selection, the 918 Spyder
applies the most suitable operating and boost strategy without driver
intervention, thus allowing the driver to concentrate fully on the road.
Quiet and elegant: “E-Power"
When the vehicle is started up, the “E-Power" mode is the default
operating mode as long as the battery is sufficiently charged. In ideal
conditions, the 918 Spyder can cover over 30 kilometres on purely
electric power. Even in pure electric mode, the 918 Spyder accelerates
from 0 to 100 km/h in less than seven seconds and can reach speeds of up
to 150 km/h. In this mode, the combustion engine is only used when
needed. If the battery’s charge state drops below a set minimum value,
the vehicle automatically switches to hybrid mode.
Efficient and comfortable: “Hybrid"
In “Hybrid" mode, the electric motors and combustion engine work
alternately with a focus on maximum efficiency and minimum fuel
consumption. The use of individual drive components is modified as a
function of the current driving situation and the desired performance.
The Hybrid mode is typically used for a fuel economy-oriented driving
style.
Sporty and dynamic: “Sport Hybrid"
In more dynamic situations, the 918 Spyder selects the “Sport Hybrid"
mode for its power sources. The combustion engine now operates
continuously and provides the main propulsive force. In addition, the
electric motors provide support in the form of electric boosting or when
the operating point of the combustion engine can be optimised for
greater efficiency. The focus of this mode is on performance and a
sporty driving style at top speed.
For fast laps: “Race Hybrid"
“Race Hybrid" is the mode for maximum performance and an especially
sporty driving style. The combustion engine is chiefly used under high
load, and charges the battery when the driver is not utilising its
maximum output. Again, the electric motors provide additional support in
the form of boosting. Furthermore, the gear-shifting programme of the
PDK is set up for even sportier driving. The electric motors are used up
to the maximum power output limit to deliver the best possible
performance for the race track. In this mode, the battery charge state
is not kept constant, rather it fluctuates over the entire charge range.
In contrast to Sport Hybrid mode, the electric motors run at their
maximum power output limit for a short time for better boosting. This
increased output is balanced by the combustion engine charging the
battery more intensively. Electric power is thus available even with
several very fast laps.
For pole position: “Hot Lap"
The “Hot Lap" button in the middle of the map switch releases the
final reserves of the 918 Spyder and can only be activated in “Race
Hybrid" mode. Similar to a qualification mode, this pushes the traction
battery to its maximum power output limits for a few fast laps. This
mode uses all of the available energy in the battery.
Main propulsion: the race car’s eight cylinder engine
The main source of propulsion is the 4.6-litre, eight cylinder engine
that produces 608 hp of power. The engine is derived directly from the
power unit of the successful RS Spyder, which explains why it can
deliver engine speeds of up to 9,150 rpm. Like the race engine of the RS
Spyder, the 918 Spyder power unit features dry-sump lubrication with a
separate oil tank and oil extraction. To save weight, components such as
the oil tank, the air filter box integrated into the subframe and the
air induction are made of carbon fibre reinforced polymer. Further
extensive lightweight design measures have resulted in such features as
titanium connecting rods, thin-wall, low-pressure casting on the crank
case and the cylinder heads, a high-strength, lightweight steel
crankshaft with 180 degrees crankpin offset and the extremely
thin-walled alloy steel/nickel exhaust system. Striking features of the
V8 are that it no longer supports any auxiliary systems, there are no
external belt drives and the engine is therefore particularly compact.
Weight and performance optimisations achieve a power output per litre of
approx. 132 hp/l – the highest power output per litre of a Porsche
naturally aspirated engine – which is significantly higher than that of
the Carrera GT (106 hp/l) and outstanding for a naturally aspirated
engine.
Unique race car design heritage: top pipes
It isn’t just this engine’s performance but also the sound it makes
that stokes the emotionality of the 918 Spyder. This is attributable
first and foremost to the so-called top pipes: the tailpipes terminate
in the upper part of the rear end immediately above the engine. No other
production vehicle uses this solution. The top pipes’ greatest benefit
is optimal heat removal, because the hot exhaust gases are released via
the shortest possible route, and exhaust gas back pressure remains low.
This design requires a new thermodynamic air channelling concept. With
the HSI engine, the hot side is located inside the cylinder V, the
intake channels are on the outside. There is another benefit as well:
the engine compartment remains cooler. This is especially beneficial to
the lithium-ion traction battery, as it provides optimum performance at
temperatures between 20 and 40 degrees Celsius. Consequently, less
energy needs to be used for active cooling of the battery.
In parallel in the drivetrain: hybrid module
The V8 engine is coupled to the hybrid module, since the 918 Spyder
is designed as a parallel hybrid like the current hybrid models from
Porsche. Essentially, the hybrid module comprises a 115 kW electric
motor and a decoupler that serves as the connection with the combustion
engine. Because of its parallel hybrid configuration, the 918 Spyder can
be powered at the rear axle either individually by the combustion
engine or electric motor or via both drives jointly. As is typical for a
Porsche super sports car, the power pack in the 918 Spyder has been
placed in front of the rear axle, and does not have any direct
mechanical connection to the front axle.
Upside-down for a low centre of gravity: Doppelkupplung
A seven-speed Doppelkupplung (PDK) transmission handles power
transmission to the rear axle. The high-performance transmission is the
sportiest version of the successful PDK; it has undergone a complete
redesign for the 918 Spyder and has been further optimised for high
performance. To ensure a low mounting position for a low centre of
gravity of the entire vehicle, the gear unit was turned “upside down" by
rotating it 180 degrees about its longitudinal axis, in contrast to
other Porsche series. If no power is required on the rear axle, the two
motors can be decoupled by opening the decoupler and PDK clutches. This
is the action behind the Porsche hybrid drive’s typical “coasting" with
the combustion engine switched off.
Independent all-wheel drive: front axle with electric motor
On the front axle, there is another independent electric motor with
an output of approximately 95 kW. The front electric drive unit drives
the wheels at a fixed ratio. A decoupler decouples the electric motor at
high speeds to prevent the motor from over-revving. Drive torque is
independently controlled for each axle. This makes for very responsive
all-wheel drive functionality that offers great potential in terms of
traction and driving dynamics.
Lithium-ion battery with plug-in charging system
The electric energy for the electric motors is stored by a
liquid-cooled lithium-ion battery comprising 312 individual cells with
an energy content of about seven kilowatt hours. The battery of the 918
Spyder has a performance-oriented design in terms of both power charging
and output, so that it can fulfil the performance requirements of the
electric motor. The power capacity and the operating life of the
lithium-ion traction battery depend on several factors, including
thermal conditions. That is why the battery of the 918 Spyder is
liquid-cooled by a dedicated cooling circuit. The global warranty period
for the traction battery is seven years.
To supply it with energy, Porsche developed a new system with a
plug-in vehicle charge port and improved recuperation potential. This
vehicle charge port in the B-column on the front passenger side lets
users connect the storage battery to a mains supply at home and charge
it. The charge port is standardised for the country of purchase. The
on-board charger is located close to the traction battery. It converts
the alternating current of the mains supply into direct current with a
maximum charge output of 3.6 kW. Using the supplied Porsche Universal
Charger (AC), the traction battery can be charged within four hours from
a ten ampere rated, fused power socket on the German 230 Volt mains
supply, for example. Furthermore, the Porsche Universal Charger (AC) can
be installed at home in the garage using the Charging Dock. It enables
rapid and convenient charging within approximately two hours,
irrespective of regional conditions. The Porsche Speed Charging Station
(DC) is available as an optional extra. It can fully charge the
high-voltage battery of the 918 Spyder in just 25 minutes.
Pioneering control concept: clear organisation of the cockpit
The driver is the focus of all technology in the future Porsche super
sports car. A cockpit was created for the driver that is typical of the
brand and pioneering in its clarity. It is partitioned into two basic
areas. First, there are the controls that are important for driving,
which are grouped around the multifunction steering wheel, combined with
driver information displayed on three large round instruments. Second,
there is the infotainment block that is housed in the lifted centre
console, which was introduced in the Carrera GT. Control functions, e.g.
for the automatic climate control system, wing adjustment, lighting and
Porsche Communication Management (PCM), including a Burmester high-end
sound system, can be intuitively operated by multitouch with a new type
of black panel technology.
For even higher performance: the Weissach package
For very performance-oriented customers of the 918 Spyder, Porsche
offers the “Weissach" package. These modified super sports cars can be
recognised at first glance by special colours and designs that are based
on legendary Porsche race cars. The roof, rear wings, rear-view mirrors
and frames of the windscreen are made of visible carbon. Parts of the
interior are upholstered with Alcantara instead of leather, and visible
carbon replaces much of the aluminium. Sound insulation has been
reduced. The emphasis on performance is not just visual: very
lightweight magnesium wheels reduce unsprung masses; gross weight was
reduced by about 35 kg. The benefits are experienced in further improved
dynamic performance. Other references from motorsport are six-point
seatbelts for driver and front passenger, optional film-coating instead
of body paint, as well as additional aerodynamic body parts in visible
carbon.
Porsche redefined: a new super sports car for a new decade
The 918 Spyder continues a long tradition of super sports cars at
Porsche; as technology platforms, as the driving force behind both car
emotion and car evolution and as the ultimate sports cars of their
decades: the Carrera GTS, the first Porsche Turbo, the 959, the 911 GT1,
the Carrera GT. More than any of its predecessors, the 918 Spyder is
providing key impetus for developing technologies for future vehicle
concepts. It offers a complete package of components that reflect
Porsche DNA – more concentrated than ever before.
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