Function

The basic difference is that a utility vehicle is used for the economic transport of as many goods and/or people as possible with as little road and space load as possible. The coach is more similar to passenger car because of the comfort it offers. The emissions of the utility vehicles lately also receive similar attention to that of other double-track road users. (single-track vehicles are as yet ignored)

How it works

Because of the largest possible pay load area inside the legally stipulated total length the drivers in the utility vehicle are placed right up over the front axle (bonnet vehicle) or still further forward, past the front axle. The driving position is mostly selected so that the engine is found underneath the cab. The advantage that a truck has is that the driver has a substantially better overview, however, the estimation of the vehicle width is considerably more complicated. Until recently safety belts were uncommon because of the different inertia behaviour of trucks in accidents. Generally accidents with vehicles of the same kind are problematic for whoever is in the driving seat.

Because it's a workplace, the driving seat is generally far superior to the car. They boast a combination of several spring suspension systems, also for the entire cab. The cab can be equipped for long-distance haulage right up to a complete living area. There could be a bunk-bed-cubicle behind or above the driver, with or without standing height. Heating independent of the engine, and almost all devices usually found in the household are possible. Similarly, the main activity, the actual driving is also relatively effortless. Exceptional strain is only really necessary in the case of absolutely full braking. Steering, clutch (if available) and gear changing are very similarly to passenger cars. Nonetheless, the handling of a truck in everyday traffic, is still not that easy. For example the very much longer braking distance (particularly when fully loaded) and turning corners with a road semi-trailer or even an ordinary trailer.

Truck engines were, up to about 1927, petrol driven and until approx. 1960 indirect injection diesel engines. Since then only the economical direct fuel injectors are produced, mostly still with 6 cylinders, in the case of heavy utility vehicles, one cylinder having the same amount of cubic capacity as four passenger car cylinders taken together. The performance can be read - like the gross weight rating - normally in the model name and it's not unusual that large cargo vehicles have more than 220 kW (300 HP). Still more important is the highest possible torque of at least 1000 Nm. The idling speed is somewhat lower, the maximum RPM of 2500/min is much lower than with passenger cars. One can get by, unloaded and on level roads, using only 4 of the 8 or even 16 gears. The highest gear can be also be selected, even in city traffic. The maximum revs are never used. For a speed of (slightly over) 80 km/h no more than 1500 revs are necessary for engine and fuel conservation, so it's no wonder that heavy utility vehicles can generally travel up to 1 million km with the same engine.

When purchasing a new truck the intended application is the main consideration. Between a vehicle mainly for construction site work and a long-distance road train there are vast differences, not only concerning the cabin equipment. The purchase decision starts with the number of- and the function of the axles. It is possible to have two front axles as well as two rear axles (see figure above). These can be driven or simply distribute the weight more evenly over the road surface. The latter are called fore-running- or coasting axles, depending on how they are arranged in regard to the driven axle. Up to four driven and two steerable axles use, apart from the distribution gearbox, a large number of drive shafts and steering elements.

However, this is more applicable to construction site vehicles. In this case the formation of the axles is dependent on the angle of the driving slope and the ground clearance. This is often less important for long-distance road trains. However, the necessary number of gears can be similar because with more gear speeds the driving speed does not decrease that much on steep-gradient highways. In this case, the maximum of 16 gears are used whereby many more are still possible. The question of locking differentials is also decided more in favour of construction site vehicles. Perhaps this explains the poor performance of long-distance road trains on icy roads.

Depending on the planned loading of the vehicle, pneumatic suspension makes sense, this means a considerable additional charge and an accordingly changed wheel guidance. Nowadays the tyres, which used to be a weak point in the truck, have become much more reliable. They cannot of course, be changed any more without an assembly device on the wheel rim or even be repaired. However, the seldom necessary changing of a tyre is, because of the size and weight, not quite without problems. The brake when driving the truck is comparable - although absolutely different in function - in terms of its operational features with a passenger car. The only exception being the possible inclusion of a third brake, - generally completely non-wearing - which protects the first and second brake from overheating and thus prevents possible danger to its surrounding.

Regulations

Light Delivery Vehicles (LDV) are now included in the previous EU-wide regulations for trucks (3.5 - 7.5 t). The maximum time behind the wheel has been reduced to 56 hours per week, the obligatory daily resting time has been raised to 9 hours. In 2006 the digital tachograph which stores its data for 1 year should be introduced. 08/08