Ultimately, haulage companies’ key concern is to arrive safely and on time, even if the road conditions are less than ideal. Between the conventional rear-axle drive and classic all-wheel drive, MAN offers the innovative HydroDrive® hydrostatic front-axle drive, providing greater traction for road vehicles that occasionally need to travel off-road. MAN is the only manufacturer on the market to offer a HydroDrive® system both for vehicles with manual transmission and for those with an automatic gearbox.
When compared with a vehicle with conventional all-wheel drive, the HydroDrive® system is up to 750 kilograms lighter and uses less fuel. In addition, a powered front axle provides extra lateral guidance – an important safety aspect to consider in winter.
The driver decides for themselves whether HydroDrive® should provide additional power automatically or if they want to switch the system on whenever additional traction is required.
MAN HydroDrive® is the perfect drive for applications with occasional off-road sections and situations where increased traction at the front axle is required. Vehicles with MAN HydroDrive® are primarily road vehicles that are equipped with hydrostatic front-axle drive to extend their scope of use in terms of available functions.
Examples of typical driving situations where MAN HydroDrive® can be switched on include:
Unsurfaced roads, such as country lanes and construction sites
Slippery subsurfaces, such as sludge, ice and snow
Route profiles with hilly topography
The hydrostatic front-axle drive can also be switched on using the rotary switch when the loaded vehicle is in motion. It switches off automatically when the vehicle reaches a driving speed of approx. 28 km/h. If the speed drops below 23 km/h, it automatically switches back on. When the MAN HydroDrive® is active, an indicator light shows on the driver’s display.
With MAN HydroDrive®, a hydropump on the gearbox output supplies the wheel hub drives at the front axle. This ingeniously simple, robust and maintenance-friendly technology is comparable with the conventional rear-axle drive in terms of fuel consumption and wear, and offers a range of advantages over the classic all-wheel drive. The distributor gearbox, a typical feature of the classic all-wheel drive, is no longer required where hydrostatic wheel drives are used. In addition, with MAN HydroDrive®, only the rear wheels are powered in road traffic, and no friction is produced by the hydropumps or wheel drives. In contrast, with the all-wheel drive, the transmission elements of the front-axle drive continue to turn, even when they are switched off.
The advantages of the MAN HydroDrive®:
More favourable fuel consumption
Weight or payload advantage of roughly 750 kg when compared to the classic all-wheel drive
The vehicle does not need to be tall: the overall height and centre of gravity of the road vehicle remain the same
Greater driving safety thanks to improved traction and directional stability on unsurfaced roads and in wintry road conditions
Transfer of engine braking action to the front axle during coasting which leads to improved distribution of braking forces