By the planned end of construction in 2021, a total of 300,000 m² of asphalt will have been paved at the Fürth/Erlangen interchange. Of this, 2.4 km is porous asphalt on the A3, and 2.3 km is low-noise stone mastic asphalt on the A73. For this construction project, one of the largest traffic projects in Germany, Max Bögl is also using state-of-the-art compaction technology from BOMAG.
Max Bögl, a long-standing BOMAG customer, already relies on the market leader’s equipment for 80% of the fleet, and is also testing the BW 174 AP Hybrid with ASPHALT MANAGER and BOMAP. The pivot-steered BW 174 AP AM Hybrid tandem roller is one of BOMAG’s answers to requirements to reduce energy consumption and emissions on the one hand, and to increase performance and efficiency on the other.
BOMAG's hybrid drive concept makes the machines quieter and more economical, and therefore more eco-friendly. In addition, the integrated hydraulic hybrid accumulator offers dynamically retrievable power storage to provide top performance on demand. It has the capacity to generate up to 100 Nm and 20 kW of additional power, which corresponds to a total output of 75 kW and thus the level of its conventional sister rollers. In push mode, the hydraulic accumulator is recharged without the use of external energy. The combination of optimised diesel engine, hydraulic accumulator, automatic compaction control (ASPHALT MANAGER) and BOMAP make the tandem rollers a highly efficient system solution.
The roller quartet consists of the tandem rollers BW 174 AP-4 AM, BW 174 AP AM, BW 154 ACP-4 AM and the BW 174 AP AM hybrid tandem roller.
The hybrid roller has the same system performance as the conventional tandem rollers of the BW 174 series. However, the 75 kW are divided into the 55 kW diesel engine and the 20 kW hybrid accumulator. This reduces the fuel consumption of the hybrid model by about 20%, and the CO2 values drop accordingly. This is made possible by the integrated diesel engine which meets the limit values of emissions standard V. The combination of particulate filter, oxidation catalyst and a cooled exhaust gas recirculation system enables the BW 174 AP Hybrid to run without additives such as AdBlue. In addition, the roller drivers experience the hybrid model as considerably quieter and thus more pleasant when rolling.
One thing all the machines have in common is, for example, the permanent 4x4 drive for best traction on very soft ground, as is the case with the Hof-Gattendorf project. When the specified daily output is as demanding as here, it is important to work fast. In addition to time pressure, the weather is an unpredictable factor, as is now the case in autumn. The more it rains, the more slippery and soft the ground becomes, which increases the demands on the stabilizers. The combinable articulated and rear-wheel steering on each machine generation ensures flexibility and maximum manoeuvrability for any ground condition. The height-adjustable cab has also been retained, ensuring the driver’s comfort and clear overview. The swivel and sliding seat provides the operator with an individual sitting position and thus optimum all-round visibility. Visibility is improved even further by four fixed cameras.
BOMAP was developed by the compaction specialist BOMAG for roller drivers to support them in their responsible task in a practical and easy way. This free app can be installed like any other app on mobile Android devices. The self-explanatory, mobile solution shows the roller operator the precise compaction passes being performed while driving in real time on the screen. Thus ensuring that no pass too many or too few is performed. The roller drivers are better able to manage their paving and working times, and the site's time management is supported effectively. In addition, less fuel is required, machine wear is reduced, and the work result is optimised.
The field test took place on the night of 14–15 July 2019. Around 3,000 t of base course were installed in this night shift and compacted with the four tandem rollers. During the initial hours of testing - the measuring results were constantly monitored by the site manager and Max Bögl material planners, as well as the BOMAG product manager and regional sales manager – there was a significant difference in the tandem rollers’ position location. From the outset, the four roller drivers had no problems starting BOMAP, connecting it to the machine interface and adding the few parameters manually. The visualisation of the work results in combination with the current roller position greatly helped the drivers in the long night shift because the “normal” visual orientation at night on the “black tarmac” is very exhausting and imprecise.