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Even special vehicles enter the Euro 6 era . And a prominent place belongs to the latest Mercedes-Benz, suitable as a carrier, for road maintenance, and, in its heavier versions, to work in hard to reach areas

Fabio Quinto

From 1 January, 2014, the Euro 6 era began for commercial vehicles. And not just for the trucks we  normally see on our roads. But even for those special vehicles usually employed for the most difficult jobs, as in the case of the Mercedes-Benz Unimog, extensively used in Italy  for summer and winter road maintenance. Or to access those sites or perform those maintenance jobs located in the most inaccessible places, such as mountain areas.

The Unimog, however, is something more: in a category of its own, full of technical innovations and able to capture the hearts of fans.  In fact, even in our country, there’s a fan club, the Unimog Club Italy.The new version is called Unimog BlueTec 6. The range, for now, includes equipment carriers  ranging from the "small" U-216 (10 t GVW) to the "big" U-530 (16.5 t). All vehicles can be equipped with snowploughs, salt spreaders and lawn mowers, can be used for agricultural purposes, and in normal and “bimodal” versions, with both rubber and steel wheels.

For the bigger Unimogs, with cargo beds and therefore better suited to transport cargo - including the Unimog 5000 -, we’ll have to wait a few months. The Unimog evolution, however, is not relegated only to engines and post-treatment systems for reducing emissions: from the design and the interiors to the new  Easy Drive traction, this Unimog is completely new. Beginning with the design: the Mercedes Benz star now stands on a single horizontal element , instead of the grid present on the old series. The U 318 and the U 530 models also feature the headlamp bezels matching the body colour. Overall, the look is more muscular. Forward visibility has been improved thanks to the large windshield, the front overhang reduced to a minimum and  the wipers now positioned at the top of the windshield rather than at the bottom. In case of maintenance work requiring  good upper visibility ( for example, in tunnels ), the wipers can be moved to the sides of the windshield. The view over any front equipment installed can be further improved by installing a front camera, controlled via a monitor placed inside the cabin. In addition to the front camera , there is also a rear one, and two other additional cameras can be installed at different points of the vehicle, depending on the set up. Even on this series, the rear three-way tipper body is supplied by the Italian company Scattolini.The major changes, however, relate to the engines. The Unimog is equipped with three different engines of the Mercedes Blue Efficiency Power range. Starting with the OM934, a four-cylinder 5.1 litres with an output of 156 hp for the U 216; 177 hp for the U-218 and U-318; and 231 hp for the U-523. The Unimog U 427 instead received the 7.7-liter six-cylinder OM936, with an output of 272 hp, which rises to 299 hp for the U 430 and U 530: a historical record for the Unimog.Similarly to other Mercedes trucks, the Euro 6 standard certification has been achieved by combining SCR catalyst system, exhaust gas recirculation (EGR) and a particulate filter. Compared to the previous Euro 5 version, where only the SCR system was used, the combination of the three  post-treatment systems results in a reduction of AdBlue consumption, gone from 5 to 2.5% of the amount of fuel used. Despite the addition of the two systems, the space remains unchanged: the particle filter is in fact located on the right side of the vehicle, just behind the front axle, near the SCR catalyst. The radiator, larger than in the past, is  placed on the left side, rather than on both sides of the vehicle. The particulate filter is equipped with active and passive automatic regeneration, and requires maintenance every 4200 hours of operation.

In addition to the Euro 6 certification, the most interesting development is represented by the continuous or Easy Drive traction, a combination of manual transmission and hydrostatic drive that allows the driver to switch from one system to another while driving, depending on the purpose. The new hydrostatic drive allows the Unimog to reach a maximum speed of 50 km/h , with power increased by 20%. Usually the operator will choose it when using different tools on an ongoing basis , without interruption. In this way, work becomes more productive and reduces clutch wear.

On road transfers the manual transmission comes into play, which allows a reduction in fuel consumption . In this case there are 8 forward and 6 reverse gears, that can be activated with a lever behind the steering wheel, allowing a maximum speed of 90 km/h. The transition from one drive to another is made by using a joystick , the lever behind the steering wheel or the accelerator pedal. The Unimog manoeuvrability is also favoured by the presence of the EQR (Electronic Quick Reverse ) , which is standard on all models , allowing you to quickly switch from forward to reverse using another lever behind the steering wheel.Suspensions too, deserve some attention. Standard equipment on the Unimog  is the portal axle with coil suspension. The bigger Unimogs, the U 3000, U 4000 and U 5000, are equipped with push rods on the drive shaft, wishbones and coil springs. Such layout, unusual for an industrial vehicle, allows long vertical excursions of the wheels and wide axle pivot. The front and rear anti-roll bars enhance cornering stability and driving safety.

In this way, all four wheels always touch the ground, even on the most inaccessible and uneven grounds.Over 60% of the Unimogs sold in Europe are used for winter road maintenance: milling cutters, spreaders and snowploughs. The percentage is even higher in Italy, in view of the difficulty in obtaining the necessary approvals for agricultural use, something very common in Germany and other countries.

Above winter road maintenance, the Unimog, properly set up, proves vary capable in other kinds of maintenance work such as grass cutting, clearing, mulching, cutting branches and various high altitude operations, as well as fire fighting. Still in the field of road maintenance, it’s possible to carry out tunnel washing operations, oil removals and marking lanes. Also interesting is the bimodal version with steel wheels, which can tow up to 40 two-axle wagons, for a total of 1,000 tonnes. Some are also in use on the Italian railway network.

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