Review

Drive technologies for mobile working machines are constantly undergoing changes. In the past, diesel engines and hydrostatic drives emerged as important systems and components. The term hydraulic excavator can be regarded as an appropriate example for that.

Nevertheless, new approaches came up in the past. In the middle of the 90’s, the company Vögele AG launched the road paver Super 1800 DE with a diesel-electric drive. Advantages of the paver are 50% less fuel, 50% less exhaust gas and up to 30 decibel quieter.

Years later, mobile working machines with hydrostatic drives experienced their first peak. Machine manufacturers concentrated on the development of wheel loaders, hydraulic excavators or also on road construction machines with hybrid drives. However, the lack of suitable battery technology prevented a serial production at that time.

To comply with the current emission legislation, diesel engines were equipped with complex off gas cleaning systems and hydrostatic drives were optimized energetically.
 

New Framework Conditions

In the automotive sector, diesel engines are meanwhile loosing their market share and therefore carmakers put their focus on vehicles with electric drive. According to a machine manufacturer, this can lead to a decreasing application of diesel engine technology (e.g. injection systems) in mobile working machines. Hence, battery technology is currently expanding tremendously.

In the whole world, metropolises put their effort on reducing further air pollution. The German cities Munich and Stuttgart are already preparing driving bans for vehicles that do not comply with the future emission legislation.

In future, the allocation of construction projects is also going to be influenced by the fact whether the construction company owns environmentally friendly machinery. Machines with environmentally friendly drives, e.g. concrete mixer with electric drum drive, can take advantage of special laws on public roads, which enable them to use bus lanes so that their destination can be reached in a much shorter amount of time.

This is going to have an impact on the drive technology of mobile working machines. Manufacturers that produce machines with futuristic technology are going to succeed
 

Construction Kit of the Future

In the future, market entrants with new drive concepts will join the established providers of drive technology (see table 1). Thus, developers and engineers will have access to a bigger construction kit that enables them to realize new machine concepts (e.g. hybrid drives, electrohydraulic solutions).
 

New Drive Concepts - Construction Kit of the Future

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New drive concepts cause profound changes for other technologies.

Especially suppliers in related areas (e.g. exhaust, control and sensor technology) should be aware of that.

 

System innovations will play an important role in future drive technology for mobile working machinery

New machine concepts – Opportunities for forward-thinking machine manufacturers and suppliers

Within the next few years, mobile working machines will undergo a fundamental change. Besides lower exhaust emissions and higher machine efficiency, topics like Internet of Things and Big Data will gain greatly in importance. Major machine manufacturers already put a focus on connectivity.

Further, robotics and automation technology will increase in construction and agricultural machinery. While there is a focus on the development of the resolution of existing machine architectures, e.g. Fendt’s project MARS (Mobile Agricultural Robot Swarms), there is also an increasing emphasize on integrated solutions. In the past, the Swedish multinational manufacturing company Volvo already introduced a combination of road paver and compressor.

Current examples are from Volvo CE the full electric compact excavator EX2 and from John Deere a backhoe loader.
 

Volvo CE fully electric compact excavator EX2

• Volvo CE introduced its fully electric compact excavator EX2 in May 2017 at Volvo Group Innovation Summit.
• In the EX2, two lithium-ion batteries with 28 KWh in total replace the combustion engine.
• The hydraulic architecture is replaced by an electric architecture with electromechanical linear actuators to optimize power transmission.
• The elimination of hydraulic system, combustion engine and required cooling lead to a significantly lower noise emission.
• The current EX2 is a research prototype; industrialization will require further analyses.
• Some partner companies were involved in this project, e.g. Bonfiglioli, Elbi, EFS, SymbioFCell and Prollion.
• Volvo CE mentions the following advantages of the fully electric compact excavator:
  o  Enough capacity for 8 hours of work (e.g. excavation of compacted soil
  o  Zero emissions
  o  Ten times higher efficiency
  o  Tenfold lower noise level
  o  Lower total cost of ownership
   

John Deere Backhoe of the Future

• Material and technology innovations are in the foreground: The weight should be reduced at least 20% and environmental pollution at least 10%.
• Hybrid drive as a combination of high performance and efficiency at low weight and maximum productivity.
• Lower center of gravity and improved view on the working area.
• The stabilizer enables a longer wheelbase with airless radial tires and thereby a higher transport stability and more space in the driver’s cabin.
• Driver’s seat and control units are separated from the rollover protection structure (ROPS) in order to reduce vibrations and noise to a minimum level.
• Electric all-wheel steering enables the machine to maneuver in narrow areas.
• Integrated interfaces with augmented reality for a convenient operation.
• An intelligent and predictive maintenance reduces downtimes and optimizes fleet management.
• New materials are used for the construction, which enable transport of higher payloads. The light exoskeleton made of metal and the spring-loaded hybrid drive support the construction of a lightweight excavator.

Summary

Drivers of new drive technologies are not only energy consumption and emission reduction. It is rather about

• Automation of machine functions (autonomous machines),
• More dynamic and precise workflows and thereby a higher machine efficiency,
• Machines with intelligent sensor technology that enable Internet of Things and Big Data.

Finally, an easier maintenance can be mentioned as another driver. Service companies estimate that the troubleshooting for electric drives is less complicated than for today’s hydraulic drives.

The present article is based on our new study that deals with the topic
“future drive technology for mobile working machines 2020/2025”.
 

The study is focused on the following key questions:

The results of the study build the basis for a roadmap about future drive technologies for mobile working machines.
It takes the perspective of the component suppliers and the external framework conditions into account.

For further questions concerning the contents and the purchasing conditions,
please send us an email or call us under +49 7621 55 00 444 or +86 21 2218 3015.