The first of these concerns ride comfort. The increased ground clearance and generous tyre size brings a decided improvement when driving over obstacles while the stiffer body helps improve the acoustic and vibrational qualities. 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.

The Q4's four wheel drive with Torsen C self-locking differential makes it possible to achieve improved roadholding, driving satisfaction and smooth responses. Other engineering configurations with electronically controlled couplings do not confer the optimum balance between oversteer and understeer and smooth performance achieved on the Crosswagon Q4, which translate into great active safety.

Preferential distribution to the rear axle also adds to driving satisfaction because it makes the car easier to handle while ensuring maximum stability when the car suddenly veers at top speed on the motorway, as can happen during emergency manoeuvres.

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 vehicle can easily overcome tricky obstacles that may cause the car to twist with one wheel completely off the ground.
The Crosswagon Q4 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. For these reasons, the Alfa Crosswagon Q4 is unique in the 4x4 scenario.

Suspension

Driving satisfaction is always a strength of Alfa Romeo cars and the Crosswagon Q4 is no exception. The model reprises the layout adopted on the 156 with some adjustment: high double-wishbone suspension that optimises the area of contact between tyre and ground; MacPherson rear suspension with transverse rods of different lengths for unique stability and handling.

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 been revised to increase car stability during pull-in, release and braking 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 dampen 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 in 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 Q4, 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 best results because we have succeeded in insulating out all noise and absorbing the minor roughness that often causes annoying knocking sounds to reverberate from the body.

Power unit: 110 kW (150 bhp) 1.9 JTD 16v M-Jet

At the end of 2002, Alfa Romeo introduced its 140 bhp 1.9 16v M-Jet, the first of the second generation of Common Rail engines in the world. The engine was adopted on the Alfa 147, 156 and Sportwagon with a sporty six-speed manual gearbox and has now been further developed for the Alfa GT, offering a power output of 150 bhp. And this very engine will also be used on the new Crosswagon Q4: a 4 cylinder in line engine with a bore of 82 millimetres and 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 M-Jet includes two new strategies for automatically calibrating and balancing the diesel injected to lower noise and reduce vibration.

It goes without saying that the Alfa Crosswagon Q4 guarantees extremely attractive performance figures: the top speed is 192 km/h and acceleration from 0 - 100 km/h takes place in 10.5 seconds.

All this comes with very frugal fuel consumption, the new all-terrain sports coupé offers:
 

• 9.3 l/100 km over an urban cycle.
• 5.8 l/100 km over an extra urban cycle.
• 7.1 l/100 km over a combined cycle.

The Multijet system, secret of second generation JTD engines.

The underlying principles of second generation turbodiesel engines remain the same, i.e. high injection pressure and electronic injector control. But one extra feature has been added: during each engine cycle, the number of injections increases over and above the current number of two. In this way, the same amount of diesel is burnt inside the cylinder but in several portions to achieve smoother combustion.

The advantages include lower running noise, reduced emissions and a 6-7% increase in performance. All this comes with a level of engine efficiency that improves car handling still further.

These results are not to be underestimated, particularly because they are obtained with an engine that represents an incredible leap forward from prechamber diesels and even improves on first generation JTD engines. The secret of the Multijet engine lies in the control unit that governs the electric injector opening and closure system (and also in the injectors themselves). The crucial element is the electronic control unit itself that can perform a set of injections that may be very closely spaced.

Fiat Auto's researchers developed the part (together with the injectors) especially for this application. It is designed to deliver the multiple injections that assure the designer more accurate control of pressures and temperatures developed inside the combustion chamber and also more efficient use of air taken into the cylinders.

This enables further goals to be achieved: quieter combustion, reduced emissions and increased performance. The Multijet system is underpinned by long years of research. Our engineers began by resolving the problem of limits imposed by the control units. Then they went on to map the benefits they could achieve by plotting different multiple injection sequences (two secondary injections very close to the main injection; one secondary injection not too close to the main injection plus two closely-spaced secondary injections; one secondary injection and then two main injections close together after a certain period etc.) against different engine service conditions: in the idling region; with low loads and low rpm; with high rpm and moderate load; with low rpm and high load etc.

The study revealed the potential of the system and showed that great benefits are achievable in all cases, though these tend to focus on one field or another according to the type of sequence chosen and the engine service area targeted. In some cases, for example, the priority is to reduce start-up times and fume levels, in other cases it is to increase torque and reduce noise while in others it is to reduce emissions and ensure a quieter drive.

And this hard work has led to the creation of the Multijet engines: another first for the Fiat Group in the diesel engine field. But we had been putting in a lot of hard work behind the scenes since 1986, the date that marked the arrival of the Croma TDI, the first direct injection diesel vehicle in the world.

At that time, this represented a true engineering breakthrough that was later adopted by other manufacturers. Direct diesel injection engines offered better performance and lower fuel consumption but failed to resolve the problem of excessive engine noise at low rpms and while speeding up or slowing down. So work began on a more advanced direct injection system and a few years later this led to the development of the Common Rail principle and the Unijet system.

The idea first came from the Zurich University research laboratories where scientists were working on an injection system that had never before been applied to a vehicle, i.e. the Common Rail system. The idea is simple yet revolutionary. If you continue to push diesel into a tank, the pressure inside will rise and the tank itself will become a hydraulic accumulator (or rail), i.e. a reserve of pressurised fuel ready for use.

Three years later, in 1990, the Unijet system developed by Magneti Marelli, Fiat Research Centre and Elasis on the Common Rail principle entered the pre-production stage. This stage was complete in 1994, when Fiat Auto started to look for a partner with superlative knowledge of diesel engine injection systems. The final stage of the project, i.e. completion of development and industrial production, was eventually entrusted to Robert Bosch.

Now our story has reached 1997 and the launch date of the Alfa 156 JTD with its revolutionary turbodiesel engine. Compared to conventional diesel power units, the JTD guarantees an average improvement in performance of 12% together with a 15% reduction in fuel consumption. These results meant that cars fitted with the engine were an immediate hit.

Now the time is ripe for the second generation of JTD engines, the Multijet and multivalve units: in 2002 with the 1.9 M-Jet 16v (forerunner of this new family of multipoint injection engines) in 2003 with the 1.9 upgraded to 150 bhp for the Alfa GT and the 129 kW (175 bhp) 2.4 JTD Multijet 20v available on Alfa 166, Alfa 156 and Sportwagon models. Now comes the turn of the Crosswagon Q4 to enjoy all the benefits of the 150 bhp 1.9 JTD 16v M-Jet.