Alfa
Romeo marks its return to the four wheel drive world with the world premier of
the Alfa Crosswagon which will go on sale in the second half of 2004. Alfa Romeo
has entered this segment with the aim of improving on the current crop of all
road vehicles: the very Alfa dash of elegant sportiness it adds brings a
completely new and unique dimension to the segment.
This new stylistic approach is very apparent in the Station Wagon version. The
model, designed by the Arese Style Centre, features an unmistakable Alfa Romeo
shape. But the trait that really typifies the Crosswagon is crossover appeal
since it combines the off-road performance of an SUV (Sport Utility Vehicle)
with the driving satisfaction and handling of a compact Alfa Romeo while
offering a versatile, functional Station Wagon passenger compartment.
The Crosswagon expresses its greater versatility (higher ground clearance with
improved approach and exit angles when cornering), a strong aesthetic
personality, great safety and overall solidity plus outstanding comfort in all
service conditions. These features make the new model perfectly at ease around
town or on unsurfaced roads yet do not detract from its sporty, stylish,
clean-cut line: a trait common to all Alfa Romeos.
The Crosswagon owes its all-terrain look in particular to underdoor aluminium
protections, special front and rear bumpers with aluminium inserts, an original
bumper grille and carrier bars. In a word, the Crosswagon was created to
overcome any road situation without ever stooping to compromises. This is also
evident in a ride set-up that is nearly 6 centimetres higher than the
Sportwagon's and the 225/55 R17 all season wheels with special compound and
tread. The tyres are also designed to offer great comfort under normal driving
conditions with good grip and a safe drive on snow, unsurfaced or uneven roads,
mud or treacherous roads in general.
Inside, the new model features an instrument panel with brand new design, a
compass built into the mirror plus special carpets and mats, an elegant, new
hi-tech trim for the central console and, optionally, new top quality leather
upholstery. So much for the external appearance of the new Crosswagon. The real
revolutionary aspect lies in its 4x4 drive system with three differentials and a
Torsen C system that distributes variable torque over the front and rear wheels.
Style
The Alfa Crosswagon is immediately recognisable for its unmistakable Alfa shape
made up of exactly the right mix of surfaces, style, poise and sportiness. The
new vehicle also has its own specific identity and is highly versatile due to
its higher ground clearance and improved approach and exit angles. Despite its
strong personality, it never strays beyond the boundaries of sporting good taste
imposed by Alfa Romeo stylistic canons.
The power and attitude of the Crosswagon are emphasised by a bigger gap between
the wide tyres and wheelarches that is not, however, as exaggerated as on a
conventional off road vehicle. The new model also conveys a sense of safety and
overall solidity. The bumpers, for example, play a fundamental role in
characterising the vehicle. They are designed with lines that confer strength
without ever losing sight of style and good taste. They include a metal alloy
insert in a central area that acts as a protective shield. The rail covers also
speak the same stylistic language: they are bound to be generously sized to
offer side protection but are made slimmer and more dynamic by a longitudinal
metal insert. A two tone body is used to sophisticated and exclusive effect in
line with the vehicle's style. It offers a functional exterior for unsurfaced
country roads and looks stylish around town as well. The 9 body shades (4 new)
are all based on a palette of natural colours and available in fine grain and
medium-coarse grain versions to enhance the colour highlights created by the
Crosswagon's sinuous shape.
Four wheel drive
The Alfa Crosswagon transmission features 4 permanently engaged drive wheels,
three differentials and torque distribution preferentially to the rear.
The Torsen C differential continuously modulates torque distribution between
front and rear axles according to grip. This feature makes for a sporty drive
that in turn increases active safety.
The mechanical modulation is continuous and progressive. It conveys an optimum
driving sensation that is satisfying and easy for the driver. Torque
distribution takes place without any time lag. The car's grip performance adapts
gradually in linear fashion to changing road conditions. This mechanical system
is complemented by an electronic system for extra performance and safety margins
in line with the Alfa Romeo philosophy.
The Crosswagon is absolutely cutting edge as far as engineering is concerned and
offers unexpected benefits.
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Beginning with ride comfort. The
increased ground clearance and generous tyre size brings a decided improvement
when driving over obstacles while the stiffer body helps lower sound resonance
effects. Because not all the torque needs be transmitted through the front
axle, it has been possible to configure the geometry of the double wishbone
front suspension for ride comfort.
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Permanent traction makes it possible
to increase roadholding, driving satisfaction and smoothness of response. No
other four wheel drive, implemented using electronic couplings, can offer the
same optimum balance between oversteer, understeer and smoothness of response
typical of the Crosswagon, that translates into great roadholding and active
safety. Preferential torque distribution to the rear axle adds further driving
satisfaction because vehicle handling is improved while guaranteeing maximum
stability during sudden high speed lane changes on the motorway, as sometimes
happens during emergency manoeuvres.
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Off-road performance is also better
than expected. The driver need no longer fear transmission lag and the
combination of electronic and mechanical control makes differential locking
effective in extreme conditions. For example, the car negotiates demanding
obstacles like twists, where one wheel is completely off the ground, with
complete aplomb. In short, the Crosswagon is four wheel drive Alfa Romeo
style: an essentially mechanical system complemented by the most advanced
electronics to assure maximum driving comfort together with optimum
performance and total safety.
Suspension
Driving satisfaction is always a strength of Alfa Romeo cars and the Crosswagon
is no exception. The model therefore repeats the layout adopted on the 156 with
some adjustment: high double-wishbone at the front, MacPherson at the back with
transverse rods of different lengths.
The earlier version has been redesigned and optimised due to the car's higher
ground clearance compared to the basic model while also maintaining the steering
feel and precision typical of an on-road Alfa 156. The rear suspension has also
been revised to increase car stability during pull-in, release and breaking to
adapt to four wheel drive performance.
In detail, the choice of a double wishbone layout for the front suspension meets
a specific aim: to achieve maximum lateral hold, a highly effective and precise
steering response and excellent traction - and to wed these specifications with
an ability to absorb and damp road surface roughness typical of the most
comfortable cars in the segment. The double wishbone layout allows high
longitudinal flexibility to be achieved on the wheel side without impairing
roadholding on corners and steering dynamics. The car's on-road behaviour is
aided by a rear suspension that gives the model the greatest stability during
high speed manoeuvres and all the agility required of a true sports car over
tight mixed routes. Hence the choice of a MacPherson suspension featuring
asymmetrical arms and refined elastokinetic properties. On the Crosswagon, the
rear suspension is connected to the chassis by a crossmember made out of vacuum
cast aluminium. The benefits of the MacPherson strut layout include low weight,
great comfort (assured by extensive wheel travels and longitudinal flexibility)
and numerous ride control options. The front and rear suspension layout also
allows the various joints, including the steering arm joints, to yield in a
calibrated manner without this affecting driving precision. The set of features
adopted allowed us to achieve the very highest level results in terms of
insulating out all noise and absorbing the minor roughness that often causes
annoying knocking sounds to reverberate from the body.
Engine and gearbox
Power and character. The Crosswagon combines the great driving comfort offered
by its suspension with all the exuberant character of an Alfa sports model. This
explains why the new model is equipped with the powerful 1.9 JTD 16v Multijet
developing 110 kW (150 bhp) plus a 6 speed manual gearbox with sports ratios.
The unit is a 4 cylinder in line engine with a bore of 82 millimetres and a
stroke of 90.4 mm, capable of delivering a power output of 110 kW at 4000 rpm
and a torque of 305 Nm (31 kgm) at 2000 rpm. The new turbodiesel has undergone
several engineering changes to increase performance and engine torque at low
speeds and to reduce noise and vibration levels. For example, the Common Rail
system used on the 1.9 JTD 16v Multijet includes two new strategies for
automatically calibrating and balancing the diesel injected to lower noise and
reduce vibration.
Braking system and active safety systems
The Alfa Crosswagon braking system is hydraulic, power-assisted and consists of
two independent crossover circuits. This particularly effective system offers
prompt, smooth braking and short stopping distances. In particular, the front
discs, derived from the GTA, are ventilated with a diameter of 330 millimetres
and come with four piston (38 and 42 mm) aluminium fixed Brembo callipers. The
rear discs are only slightly smaller at 276 millimetres.
In addition to a high-performing brake system, the Alfa Crosswagon also comes as
standard with a BOSCH 5.7 ABS, one of the most advanced systems available on the
market today. It features four active sensors and a 12 valve control unit. The
ABS contains an electronic brakeforce distributor (EBD). This device apportions
braking action over all four wheels to prevent locking and ensure full control
of the car under all conditions. The system also adapts its operation to wheel
grip conditions and brake pad efficiency to reduce pad overheating.
The Crosswagon also assures absolute mastery of the car in all conditions,
however extreme, due to its VDC (Vehicle Dynamic Control) and ASR (Anti Slip
Regulation) systems.
More specifically, the VDC is Alfa Romeo's version of the ESP (Electronic
Stability Program), an innovative device that cuts in under extreme conditions
when car stability is at risk and also helps the driver control the car. As
befits a true Alfa, the VDC is a sporting device that allows outstanding
roadholding. It allows the driver the full satisfaction of controlling the car
as long as conditions are normal but cuts in just before things become critical.
The VDC is permanently engaged.
The MSR (Motor Schleppmoment Regelung) cuts in when the gear is shifted down
abruptly in low grip conditions. This device restores torque to the engine to
prevent the wheel skidding as a result of lock.
To achieve this result, the VDC continually monitors tyre grip in both
longitudinal and lateral directions. If the car skids, it cuts in to restore
directionality and ride stability. It uses sensors to detect rotation of the car
body about its vertical axis (yaw speed), car lateral acceleration and the
steering wheel angle set by the driver (which indicates the chosen direction).
It then goes on to compare these data with parameters generated by a computer
and establishes - via a complex mathematical model - whether the car is
cornering within its grip limits or if the front or rear is about to skid (understeer
or oversteer). To restore the correct trajectory, it generates a yawing moment
in the opposite direction to that which gave rise to the instability by braking
the appropriate wheels (interior or exterior) individually and reducing engine
power (via the throttle). This is the key attribute of the device designed by
Alfa Romeo engineers. It acts in a modulated fashion on the brakes to ensure the
action is as smooth as possible (and the drive is not therefore disturbed). The
engine power reduction is contained to ensure outstanding performance and great
driving satisfaction at all times.
As it carries out its complex task, the VDC stays in constant communication with
the brake sensors and engine control unit but also with:
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a Body computer that constantly
exchanges information with the ABS, engine management unit and automatic
transmission unit;
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an electronic throttle (that
communicates with the ABS in turn);
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a control panel (active warning
lights);
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the steering wheel and steering
column (via the steering sensor);
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a gyroscopic sensor installed on the
passenger compartment floor to record car yaw and lateral acceleration.
An integral part of the VDC is the ASR
(Anti Slip Regulation) system which optimises traction at any speed with the aid
of brakes and engine control.
The device computes degree of slip on the basis of wheel rpm calculated by the
ABS sensors and activates two different control systems to restore grip: when an
excessive power demand causes both drive wheels to slip (e.g. in the case of
aquaplaning or when accelerating over an unsurfaced, snowy or icy road), it
reduces engine torque by reducing the throttle opening angle and thus air flow;
if only one wheel slips (e.g. the inside wheel following acceleration or dynamic
load changes), this is automatically braked without the driver touching the
brake pedal. The resulting effect is similar to that of a self-locking
differential. This enables the Alfa Crosswagon to readily negotiate icy roads -
only one wheel requires grip to transmit drive to the car - as well as off-road
twists, when an obstacle leaves the vehicle with only two wheels operative and,
of the other two, one is off the ground.
The ASR is activated automatically whenever the engine is started but must be
turned off by means of a cut-out switch on the central console.
Finally, ASR deactivation is required when snow chains are used because the
wheel must be able to slip by tiny amounts to pile up the snow so that force can
be transmitted to the ground and the ASR tends to prevent this occurring.
Short history of Alfa Romeo 4x4 cars
The first four wheel drive system in Alfa Romeo's history made its debut in 1951
on the AR51 - 1900, an off-road car with state-of-the-art engineering features
designed for military use. The 'Matta' (or crazy car - as it was affectionately
dubbed by those who appreciated its exceptional off-road properties) is now a
real cult item appreciated far beyond the restricted circle of Alfa Romeo
collectors.
The Alfa 33 4x4 made its debut in 1983. The layout adopted for this compact
saloon meant that the rear wheel drive had to be engaged by means of a lever in
the passenger compartment. A central differential prevented any slippage between
both axles. Because it offered higher ground clearance than front wheel drive
cars, the 33 4x4 acquitted itself well in many critical situations and could
pass easily from snowy surfaces to unsurfaced roads. Altogether a multi-facetted
car that allowed great flexibility of use. In 1991, the Alfa 33 (again) was
fitted with a sportier interpretation of the four wheel drive concept. The
transmission layout of the new Permanent 4 (this was the name of the version)
was more complex than its predecessor: a set of sensors managed the action of a
viscous coupling that transferred movement to the rear wheels (generally free)
when it detected significant differences between wheel rotating speeds across
both axles. These features assured the 33 outstanding dynamic performance, an
up-to-date blend of high performance, sports handling and top level active
safety.
The following year saw the arrival of the 155 Q4. The new Quadrifoglio 4 tag was
the emblem of state-of-the art Alfa Romeo sportiness. One specific feature of
the 155 Q4 was the presence of a permanent four wheel drive system with three
differentials: a conventional unit at the front; a central epicyclic unit that
engaged directly with the gearbox layshaft incorporating an integral Ferguson
viscous coupling - and a Torsen unit at the rear.
Under normal conditions, the central distribution distributed drive torque with
a slight preference to the rear wheels. If one of the two axles lost grip
excessively compared to the other, the Ferguson coupling cut in to transfer
drive torque (up to 100%) gradually to the wheels with more grip.
The efficacy of the system was further increased by a Torsen rear differential
that acted as a self-locking unit and allowed the wheels to turn at different
speeds.
This transmission configuration was combined with a particularly advanced ABS.
This technical configuration ensured that the 155 Q4 remained glued to the
ground and was easy and entertaining to drive while remaining safe in every
situation. These attributes were also displayed by the racetrack versions that
fought out the German touring car speed championship. In 1993, the 155 V6 TI saw
off the competition to triumph in the DTM with Larini at the wheel.
Alfa Romeo brought the incredible technical experience it had built up over the
years to bear when it produced a four wheel drive version of its range leader,
the 164. In December 1993, customers were able to buy a 164 Q4 powered by the
legendary 231 bhp V6 engine.
In this case, the four wheel drive layout had been further developed to ensure
maximum performance and peak driving comfort. The heart of the system was the
central Viscomatic viscous coupling developed exclusively by Alfa Romeo in
conjunction with Steyr-Puch. The Viscomatic was managed by an on-board
electronic system that communicated in real time with the engine control unit
and ABS control unit. Moment by moment, the system detected and processed
information on four different parameters: total drive torque requested, speed,
steering angle and slip difference between front and rear axles. It was able to
adjust drive torque distribution between the axles with incredible speed on the
basis of vehicle speed, cornering radius, engine rpm, throttle opening and
closure and ABS parameters. This guaranteed improved torque distribution at any
moment and in any situation. In this case too, the Q4 drive system was based on
a Torsen self-locking rear differential. This rear differential was responsible
for the important task of redistributing the torque allocated to the rear end
(in real time) between the wheels on the rear axle: this benefited traction and
also car handling over mixed routes.
An epicyclic unit was also fitted between the coupling and rear differential to
amplify speed differences between coupling input and output. This made it faster
and more sensitive while reducing the level of torque managed by the coupling.
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