Volkswagen L1 Concept la Frankfurt 2009

Autor: Oraan Mărculescu acum 11 ani Concepte auto

To the Point: Breakthrough for the 1-Litre Car
Volkswagen presents the most fuel-efficient automobile in the
world

  • L1 Concept is driven by new high-tech TDI and E-motor
  • Carbon Fibre Reinforced Plastic body of the L1 weighs just 124
    kilograms
  • Maximum speed 160 km/h; L1 consumes just 1.38 litres diesel per
    100 km
  • CO2 emissions reduced to a new best value with just 36
    g/km

Technological breakthrough for the 1-litre fuel consumption car:
International Motor Show (IAA), Volkswagen is presenting the
concept of the future L1 in a world premiere that points the way
toward the production version. The full hybrid vehicle weighs just
380 kilograms thanks to its carbon-fibre reinforced body (CFRB).
With a combined fuel consumption figure of 1.38 litres of diesel
per 100 kilometres, this extremely aerodynamic (Cd 0.195!)
Volkswagen suitable for everyday use is intended to become the most
fuel-efficient automobile in the world. CO2 emissions of the 160
km/h L1 are similarly low at 36 g/km.

Retrospective: Seven years ago, Dr. Ferdinand Piëch, at that time
Chairman of the Board of Management and today Chairman of the
Supervisory Board of the Volkswagen Group, drove a prototype from
Wolfsburg to Hamburg that was unlike any other car before it: the
Volkswagen 1-Litre car – the world’s first car with fuel
consumption of one litre fuel per 100 kilometres. The man and
machine wrote automotive history. In April 2002, however, it was
also clear that the time for a production version of the 1-Litre
car lay far in the future. Production of the body itself – from
carbon-fibre reinforced plastic (CFRP) – was not realistic due to
cost considerations. Yet, in 2002 Dr. Ferdinand Piëch already
prophesised that the time would soon come for the 1-Litre car and
CFRP as a material for industrial applications. By 2009 the time
had come: Volkswagen is making a clear statement at the IAA in
Frankfurt (September 17 to 27) with the second generation of this
ingenious car: The L1 represents a step forward into the future
with completely new technology and a new design; revolutionary yet
close to production readiness.

„It is an enormous challenge to control costs in producing the
monocoque out of CFRP,” says Dr. Ulrich Hackenberg, member of the
Board of Management for the Volkswagen Brand with responsibility
for development. Both technically and visually, the CFRP body is
already considered a significant achievement in car design. Unique
on this car are the proportions of its dimensions. While the length
of the L1 at 3,813 millimetres is still similar to that of a
Volkswagen Fox, and its height of 1,143 millimetres nearly matches
that of a Lamborghini Murciélago, the car’s aerodynamically
optimised width (1,200 millimetres) has no comparisons in the world
of today’s production cars.

L1 philosophy – defining a new type of
automobile

In developing both prototype generations of the L1, Volkswagen
simply questioned everything that typically characterised an
automobile. The key starting point was body construction, and a
core question was raised here: How would a car have to look and be
built to consume as little energy as possible? The logical answer:
extremely aerodynamic and lightweight. Yet these objectives had to
be achieved under a non-negotiable precondition: a maximum of
safety. The approach taken: a narrow two-seater with a CFRP
body!

The seat layout fitting this design goal was dictated by the
uncompromising aerodynamic form of a glider: One seat behind the
other. Entry to the concept car is also similar to that of a
glider; through a roof cover hinged at the side. On this second
generation of the L1, the concept has been further honed; each
component has been redesigned, a special chassis with aluminium
components was developed, and above all the crucial CFRP technology
from Formula-1 racing and airplane construction was transferred to
automotive manufacturing. This has been combined with a unique form
of hybrid drive to create a near-production vehicle. 2013 is the
target year for this future dream to become a reality.

Note: TDI, TSI, DSG and Twincharger are registered trademarks of
Volkswagen AG or other companies of the Volkswagen Group in Germany
and other countries.

World Premiere of the L1 – Drivetrain

The Future Needs the TDI: Small TDI leverages minimal fuel
consumption and maximum range

Downsizing – 0.8 TDI is smallest diesel engine intended for
production applications ever built by Volkswagen

Electrifying idea – E-motor plus TDI pushes CO2 emissions down to
36 g/km

The TDI, E-motor and 7-speed DSG are located at the rear, and they
combine to create the most fuel efficient road-legal car hybrid
drive in the world. Proof of this are its 1.38 litre per 100
kilometres fuel consumption and 36 g/km CO2 emissions. Serving as
the primary drive source is a completely redeveloped two-cylinder
turbo-diesel with common rail direct injection (TDI). It is
operated in two different modes depending on the load conditions.
In the standard „ECO” mode, the 800 cm3 TDI develops a power of 20
kW / 27 PS (at 4,000 rpm); in „Sport” mode – used to reach top
speed, for example – the car’s power rises to 29 kW / 39 PS (at
4,000 rpm). The TDI’s maximum torque is 100 Newton-meter (at 1,900
rpm). Naturally, the L1 also has a Stop-Start system that
automatically shuts down the engine when vehicle has stopped and
restarts when the accelerator or E-pedal is pressed.

The hybrid module has been integrated into the housing of the
7-speed DSG (Direct Shift Gearbox). It is located between the TDI
engine and the DSG gearbox and consists of a 10 kW / 14 PS electric
motor and a clutch. The E-motor is supplied with energy from a
lithium-ion battery located at the front of the car. An electronic
power control module, operating at around. 130 Volts manages the
flow of high voltage energy the battery and to the E-motor. In
parallel, the vehicle’s low voltage electrical system is supplied
with the necessary 12 Volts through a DC/DC converter.

Electric motor – details of the E-motor

In normal operation the electric motor can support the TDI engine
in conditions such as by electronic load point shifting and in
acceleration. If necessary – generally during acceleration – the
E-motor can supply 40 percent additional torque over the entire
speed engine speed range. Moreover, the E-motor can propel the L1
over short distances by itself. In this case, an auxiliary clutch
decouples the TDI from the drivetrain. Restarting the TDI is a very
easy process. In so-called „pulse starting” of the TDI, the
electric motor is sped up and is then coupled to the TDI unit to
provide almost instant starting. The entire process takes place
automatically and without jolts, so the driver hardly notices the
restarting of the TDI engine.

In braking phases, the E-motor operates as a generator to charge
the lithium-ion battery by recovering braking energy. The gears of
the automatically shifting DSG are always selected with the aim of
achieving the best possible fuel economy. The engine controller
regulates all energy flow and drive management tasks taking into
account the moment by moment demands for power made by the driver.
Some of the parameters used to calculate the optimum propulsion
mode for the given conditions are: accelerator pedal position,
engine load, momentary fuel demand, energy supply and the mix of
kinetic and electrical energy at any given time.

Diesel engine – details of the 0.8 TDI

The TDI engine in the L1 is a new development. Yet, even here
Volkswagen has been able to exploit synergies to design an engine
that is both innovative and cost-effective. Hence, this 0.8 litre
TDI unit has been derived from the 1.6 TDI just introduced a few
months ago. The 1.6 TDI is making its debut at the IAA in cars such
as the new version of the Golf BlueMotion (3.8 l/100 km) and the
Passat BlueMotion (4.4 l/100 km) – which are currently the world’s
most fuel-efficient production cars in their respective
classes.

Based on their common origins, the 0.8 TDI and 1.6 TDI have
identical cylinder spacing (88 millimetres), bore (79.5
millimetres) and stroke (80.5 millimetres). These high-tech TDI
engines also share key internal engine features for reducing
emissions. They include special piston crowns, multi-injection and
individual orientations of the specific injection jets. On both
drivetrains there is exhaust gas recirculation, an oxidation
catalytic converter and a diesel particulate filter. Equipped this
way, the TDIs in each Volkswagen fulfil the limits of the Euro-5
emissions standard with ease.

The 1.6 TDI, thanks to its common rail injection, is also an
exceptionally quiet and low-vibration diesel engine. These positive
properties have been successfully transferred to the two-cylinder
unit. The TDI’s aluminium crankcase was also constructed with high
precision to achieve very low friction losses. The oil pump,
designed to operate at a maximum oil pressure of 4.0 bar, also
contributes to engine efficiency.

Another example of how the entire drive system is configured for
high efficiency is the L1’s cooling system. Its external water pump
is controlled by engine management so that cooling is only
activated while engine operating conditions require it. This
thermal management also contributes to reduced fuel consumption. A
second electric water pump, also activated only when needed,
provides cooling required for the starter generator and the power
electronics in a separate water circulation loop operating at a
lower temperature level.

Automatic transmission – details of the 7-speed
DSG

Gear shifting work aboard the L1 is handled by the 7-speed DSG,
which is one of the most innovative automatic transmissions in
production. Compared to the version equipping the new Polo, for
example, the design of the Direct Shift Gearbox has been developed
to include clutch control for the hybrid module. Furthermore,
individual gear ratios have been optimised to attain responsive
driving performance despite the car’s extremely low fuel
consumption. The hybrid module is integrated into the DSG housing
as previously mentioned. It is located where the flywheel is
usually to be found.

Driving performance – economical and yet
responsive

The L1, equipped with ABS and ESP, has a top speed of up to 160
km/h – this is remarkable considering its fuel efficiency. With
maximum acceleration from a standstill, the two-seater reaches 100
km/h after just 14.3 seconds. The fuel tank holds just ten litres
yet, this is sufficient for a theoretical driving range of about
670 kilometres, given the car’s 1.38 litre average fuel
consumption.

World Premiere of the L1 – Interior

The World’s Most Fuel-Efficient Car with a Jet’s Cockpit:
180-degree cockpit offers ideal ergonomics

Tailored to the driver – Steering wheel is the centre point of the
interior

Comfortable for two – Seats offer fully-fledged long-distance
comfort

Talking about car driving as ‘piloting’ might sound out of place,
but in the case of the L1 it is wholly appropriate. The driver (in
the CFRP tube frame seat) and passenger (in the fixed CFRP seat
that is part of the monocoque) sit one behind the other. At both
locations, the seat position is ergonomical and very comfortable.
All instruments and controls are arranged over a 180 degree radius
for the driver, which places them perfectly within view and reach.
The instrument panel itself has been integrated into the monocoque
and is made of CFRP. The interior applications are produced from
glass fibre reinforced plastic (GFRP). One of the materials
Volkswagen is introducing for interior side trim is the new „Sport
Esteem” material that is as robust as it is touch-friendly.

To start the L1, the driver pushes a button on the right side of
the steering wheel. When it is rotated, the round start button
simultaneously serves as a gear selector switch and is used to
activate the electronic handbrake (Drive, Neutral, Reverse and
Park). The entry canopy and rear hatch are opened electrically by
touch controls to the left and right of the driver. Also designed
as touch sensors are controls for the entire air conditioning
control system. Via multifunctional keys in the steering wheel, the
driver controls the on-board computer, navigation and entertainment
systems.

The classic door mirror and rear-view mirror have been completely
eliminated on the L1. In their place, cameras display images on
OLED-active (OLED = organic light emitting diode) displays located
on the left and right sides of the instrument panel. A Park
Distance Control (PDC) system makes parking easier as well.

In case of a crash, not only are the driver and passenger protected
by the monocoque, which is designed as a highly rigid CFRP safety
cell, as well as aluminium crash elements in the front of the car,
but also by a steering wheel airbag and head/side curtain airbags
to the left and right inside the entry canopy.

World Premiere of the L1 – Body

Car Design of the Future: The L1’s exceedingly safe CFRP safety
cell weighs just 124 kilograms

Lightweight – L1 is no heavier than a good touring motorcycle

Revolution – Never before in carmaking history has CFRP been
applied so comprehensively to improve fuel efficiency

Both technically and visually, the CFRP body is already a
significant achievement in car design. Unique on this car: the
proportions of its dimensions. While the length of the L1 at 3,813
millimetres is still similar to that of a Volkswagen Fox, and its
height of 1,143 millimetres nearly matches that of a Lamborghini
Murciélago, the car’s aerodynamically optimised width (1,200
millimetres) has no comparisons in the world of today’s production
cars.

CFRP body – Monocoque and exterior skin

The two-seat monocoque, including the tubular frame driver’s seat
and passenger seat as well as the exterior body skin, all consist
of CFRP. There are no doors. Instead, the driver and passenger
climb into the L1 from the top. An electrically actuated entry
canopy above the seats is opened and closed for this purpose.
Headlights and taillights all utilize LED technology, which consume
a lot less energy. The rear wheels are completely covered; their
wheel covers can be removed to change the Michelin low resistance
tires („Energy Saver”: front 95/60 R16, rear 115/70 R16). The
underbody is also completely enclosed. The 0.8 TDI is cooled via
adaptive air channels integrated in the sides of the car body.
These automatically open and close based on the hybrid unit’s
operating state and vehicle speed. The tailgate is opened in the
usual, manual way. It too consists of CFRP. Inside is a stowage
space of 50 litres.

CFRP advantages – composition and weight

Carbon fibre reinforced plastic, as the name implies, consists of
multiple layers of high-strength carbon fibres, which are
integrated in a very tough matrix. This mix results in an extremely
strong and lightweight composite material. Until now, producing a
body like that of the L1 from CFRP, while conforming to industrial
standards, was an insurmountable task. Up to now CFRP was only
practical for very small production runs, as in aircraft
manufacturing or motorsport. Now Volkswagen has succeeded in
finding a production-viable and cost-effective way to produce CFRP
parts in suitable volumes.

The reason that CFRP is the ideal material for the L1 body is
demonstrated by considering its weight and strength. The L1 weighs
just 380 kilograms, which is equivalent to the weight of a very
high-end, fully equipped touring motorcycle of the 1200-cc class.
The L1, on the other hand, is an automobile through and through. Of
the 380 kilograms curb weight, 122 kilograms are taken by the
drivetrain, 79 kilograms by the chassis, 35 kilograms by interior
furnishings and 20 kilograms by the electrical system. 124
kilograms remain, and this is precisely the weight of the
body.

These 124 kilograms can be further broken down: 64 kilograms are
accounted for by the CFRP monocoque including integrated passenger
seat, 28 kilograms is the weight of the entire CFRP exterior skin,
19 kilograms for the CFRP entry canopy, 9 kilograms for the CFRP
driver’s seat and 4 kilograms for the LED lights. By way of
comparison: The body of the legendary Lupo 3L – until today the
smallest Volkswagen production car ever built – weighed 306
kilograms, and the entire car weighed a lightweight 813 kilograms.
That is 433 kilograms more than the L1.

And there are other advantages: the material’s extremely high
stress limits and its ideal forming properties for even the most
challenging of design features.

Design – anything but typical, yet a typical
Volkswagen

The design and styling of the L1 – function and form – combine to
form one uncompromising unit. Walter de Silva, Head of Design for
the Volkswagen Group has this to say: „The design of the L1
redefines classic and aesthetic vehicle traits. Especially
significant, of course, is how the nearly rocket-shaped lines catch
one’s attention. All of its moving parts are integrated so
accurately that the body resembles a rocket or jet. It is a body
that cuts through the air with minimal aerodynamic resistance.” A
top Cd value of 0.195 and 1.02 m2 frontal area (Cd x A = 0.199 m2)
is a statement that is sculpted into the CFRP.

And this is how it looks, the most aerodynamic front end in the
world: „The typical layout of conventional headlights with a
radiator grille in the middle would be entirely inappropriate
here,” says de Silva. „That is why we chose a more mini­malistic
layout and integrated the headlights into a neutral horizontal
stripe that conveys a far-sighted and contemporary feeling.” The
Head of Group Design continues: „In a sense, we applied the same
principle to the front end of the Scirocco, where the headlights
are joined by a glossy black stripe, and the brand logo is also
placed on the engine bonnet. This underscores the dynamic character
of this automobile.”

The extremely aerodynamic design also shapes the rear with its
diffuser and wheels that are completely enclosed. The most
distinctive feature of the overall appearance in the rear are the
LED taillights that were worked into the TDI’s air outlet ports. De
Silva: „The same stylistic features as in front are repeated in the
rear, in the taillights – which we have integrated in the grilles
of the two air outlet ports; they have an even more aerodynamic
appearance. Another identifying feature is the air outlet directly
behind the cockpit – a nearly abstract, graphic element that
underscores the purposeful aesthetics of this vehicle.” Due to the
driver’s low seating position, there is an additional window in the
roof that is ideal, for example, to view traffic lights.

VW L1 ConceptDupă
prima maşină VW de „1 litru la sută”, prezentată în 2002, germanii
revin cu un astfel de concept, botezat simplu Volkswagen L1
– unde L1 semnifică „1 litru/100 km”
, cu toate că, în
realitate, VW L1 afişează un consum mai mare, de 1,38 litri/100
km.

Vorbim de o maşină cu două locuri, unul după altul,
având propulsie hibridă diesel-electric şi caroserie din
CFRP
(Carbon Fiber Reinforced Plastic – plastic ranforsat
cu fibră de carbon). Lungimea de 3,8 metri şi înălţimea de 1,143
metri, cumulat cu suprafaţa frontală foarte redusă şi structura tip
„trabuc” îi conferă lui VW L1 un coeficient aerodinamic extrem de
redus, având un Cd de numai 0,195

Aerodinamica excelentaMasa
maşinii ajunge la 380 kg (din care şasiul cântăreşte numai 124
kg),
aşa încât nu ne miră nici consumul scăzut de
motorină, dar nici valoarea extrem de mică de emisii
CO2, de numai 36 g/km
. De această valoare se
face „vinovat” un propulsor diesel cu doi cilindri, de 0,8 litri,
care funcţionează în două moduri. În modul „ECO”, motorul dezvoltă
27 CP/4.000 rpm, iar în modul „SPORT” se mai câştigă 12 CP
suplimentari – dacă se doreşte rularea cu viteze mari. Cuplul maxim
al micului TDI atinge 100 Nm/1.900 rpm.

Motorul electric este integrat în transmisia DSG cu 7
trepte, oferind un plus de 14 CP
, în timp ce bateriile
litiu-ion sunt plasate în partea frontală a maşinii. La
acceleraţiile puternice, motorul electric poate suplimenta cuplul
motor cu până la 40%, pe durată scurtă, dar este capabil să
propulseze maşina şi independent de motorul termic – însă nu avem
date referitor la autonomia lui VW L1 în modul strict electric.

Per total, autonomia maşinii se ridică la aproximativ
670 km
, o valoare foarte bună. Acelaşi lucru îl putem
spune şi despre viteza maximă de 160 km/h, în timp ce acceleraţia
0-100 km/h se realizează în aproximativ 14,3 secunde.

VW L1 Concept - interiorCele
două locuri sunt gândite pentru o bună ergonomie şi un confort
crescut la drum lung, scaunul din spate făcând parte din structura
monococă a şasiului. Instrumentele de bord sunt aşezate pe o rază
de 180 de grade în jurul şoferului, bordul fiind de asemenea
integrat în structura şasiului. VW L1 presupune şi o altă premieră:
folosirea unui nou material plastic, denumit „Sport
Esteem”
, care oferă atât o senzaţie ridicată de calitate,
dar este şi foarte rezistent la uzură.

Butonul de lângă volan serveşte atât pentru pornirea
motorului, dar şi pentru selectarea modurilor de funcţionare a
cutiei de viteze automate
– prin rotirea butonului se aleg
modurile P (parking), N (neutral) sau R (reverse). Tot prin butoane
este comandată deschiderea acoperişului, dar şi sistemul de aer
condiţionat, în timp ce instalaţia multimedia este controlată de la
butoanele de pe volan.

Motor cu 2 moduri de functionareLipsa
oglinzilor retrovizoare este suplinită de adoptarea unor camere de
filmare, ale căror imagini sunt proiectate pe diplay-uri OLED
(Organic Light Emitting Diode), iar pentru manevrele de parcare nu
lipseşte sistemul PDC (Park Distance Control). Nu lipseşte nici un
spaţiu de depozitare pentru bagaje, având capacitatea de 50 de
litri.

Pe şosele, nu vom vedea prea curând un VW L1, însă acest concept
are menirea de a reliefa avantajele utilizării unei tehnologii
considerate prea costisitoare la începutul anilor 2000, şi anume
utilizarea intensivă a materialului plastic ranforsat cu fibră de
carbon, CFRP. De asemenea, cei de la Volkswagen continuă
dezvoltarea propulsoarelor diesel, sub egida BlueMotion, exemplul
de faţă fiind de aşteptat să îl regăsim sub capota maşinilor VW
foarte curând.

Mai multe detalii,
în pagina următoare
.



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