While hydraulic and machine performance and value are front and center at Bauma, sustainability is a key theme as well. Since 1991 productivity in the construction machinery sector has been flat in terms of output per hour, signifying the need for more automation, labor saving and worker safety. That’s according to Juergen Weber, head of the Institute of Fluid Power at Dresden University of Technology, who addressed the Bauma Innovation Day Research forum. On the bright side, however, there has been enormous progress in reducing noise and emissions in construction equipment, he added. And even considering the competing challenges of more-stringent regulations in western countries and cost pressures in developing markets, the trend of sustainability continues.
One such example, said Markus Schneider, a professor with the Institute, is a joint project termed the Green wheel loader that aims to increase efficiency through the use of a specialized drive and advanced controls. First, it optimizes engine speed to run at as low rpms as possible without lugging or restricting actuator functions. The loader also takes advantage of a hydrostatic power-split transmission. And implements are displacement controlled, which increases efficiency by eliminating throttling losses through the valves. Finally, it uses accumulators to recover and reuse previously wasted energy.
The prototype is built from a conventional, state-of-the-art Liebherr 24-ton loader and is considered a hydrostatic “parallel” hybrid. In operation, the system’s advanced control algorithms decouple the engine from the implements, making the drive highly efficient. In essence, control units on each implement and subsystem sense demand and communicate that with the central ECU. And that, in turn, directs the engine to run at only the speed required, and no more. Compared to typical wheel loaders, the prototype boosts savings by more than 10%. Additional gains are expected as the developers focus future efficiency efforts on several machine subsystems.
Another aspect of sustainability that perhaps deserves more attention is the need for quieter machines. While there are increasingly stringent noise regulations in regards to mobile equipment and operator safety, for the most part users are still “spoiled” by improvements seen in today’s cars, said Jan Scholten, head of the construction machinery research group at Ruhr-University Bochum.
But the problem is not easily solved. While local noise sources are well known—things like cooling systems, vibrating components and structures—their effects on total machine noise are usually considered late in the design process. At that juncture, it’s too late to optimize components and a “Band-aid” approach must instead suffice, if it’s addressed at all.
A noise-minimizing project headed by the University, with industry partners including Hydac, Liebherr and Atlas Copco, has the objective of developing a ground-up way to simulate and test components and assess their contribution to noise emissions and the effects on the surrounding structure, well before design is finalized and a machine is actually built.
In addition, the research group is well aware that most engineers are not acoustic experts, so the aim is to make the software powerful but simple. The 3D software demonstrated to date considers noise sources and vibration levels in components like pumps, valves, bearings and mounts to subsystems like hydraulic hammers and rotary carriages.
PowerBoost hybrid
On a more practical note, yesterday at Bauama Dana Corp. announced technical enhancements to its Spicer PowerBoost hydraulic-hybrid powertrains that further increase the performance, productivity and fuel economy of telehandlers and other off-highway vehicles. Customized configurations of the system now enable vehicles to supply up to 20% more hydraulic power to the work circuits and perform work functions up to three times faster than conventional vehicles. These improvements can further enhance overall productivity by up to 10% and generate additional fuel savings of up to 5% more than previous PowerBoost versions, according to the company. Ultimately, Spicer PowerBoost technology can give machine users fuel savings of up to 45%, depending on the application and duty cycle.
“For off-highway machine owners and operators, increased productivity is key to the success of their businesses, and vehicles that can perform faster in a reliable and safe way will significantly improve their profitability,” said Aziz Aghili, president of Dana Off-Highway Driveline Technologies. “This latest enhancement to Spicer PowerBoost technology enables a much higher level of vehicle performance without increasing the size of the engine or the capacity of hydraulic pumps.”
Ideally suited for hydrostatically-driven drivetrains, Spicer PowerBoost uses an advanced energy-management system to evaluate the power needed in the entire vehicle and distribute energy captured in the drivetrain, resulting in lower fuel consumption and improved productivity.
Several operating modes include an Eco mode that give maximum fuel efficiency in normal operating cycles; power mode for high acceleration and working performance in operations requiring maximum power; regenerative braking mode captures and stores energy otherwise wasted during vehicle braking; stop/start mode shuts down the engine during prolonged idle conditions and then restarts instantly at the operator’s command; and zero emission mode permits vehicle operation exclusively from stored energy captured by the system.
Spicer PowerBoost is reportedly ideal for applications with frequent, intense bursts of acceleration, deceleration, lifting, and lowering during cyclic maneuvering that support the recuperation of braking energy. In addition to telehandlers, the new system also suits wheel loaders, lift trucks, and other construction, material-handling, and on-highway vocational vehicles that perform lifting or digging operations.
High-efficiency hydraulic fluid
According to Bauma exhibitor Evonik, while fine-tuning engines, pumps, drive systems and hydraulics are all good ways to improve efficiency, a simple route to fuel savings in mobile machines is simply changing to a different hydraulic fluid. Its Dynavis additives are formulated to improve overall efficiency of construction machines versus those using monograde fluids.
Fleet owners like Nuova Ghizzoni, an Italian pipeline contractor, have switched its hydraulic excavators to fluids formulated with Evonik Dynavis technology and have seen substantial fuel savings, reports Evonik. While conventional thinking is to use the cheapest hydraulic fluid possible, users are increasingly aware that changing to a slightly more-expensive high-VI fluid can typically garner fuel saving of 10%, and up to 30% in high-load, high-demand applications.
Dynavis-formulated hydraulic fluids stay free-flowing at low temperatures to improve mechanical efficiency, and prevents “thinning” and internal leakage at higher temperatures. The result is better efficiency and response across a wide spectrum operating conditions.
Dana Holding Corp.
www.dana.com/offhighway
Evonik
www.dynavis.com
