Engineering tomorrow’s digital worksite with electrohydraulic controls

By D. Dean Houdeshell, Manager of Systems and Applications Engineering, Americas, Danfoss Power Solutions

Market trends are proving that expectations are clear around the future of the mobile hydraulics industry—we need more intelligent, high-performing machines. Over the past decade, we’ve seen a lot of changes, including the implementation of the Tier IV regulations. The selection of the correct engine size and power requirements is now more important than ever. In addition, customers are asking for high efficiency, precision control and operator comfort. All of this is moving manufacturers toward a greater use of electronics, sensors and electrohydraulic controls.

“We’ve seen this shift slowly start to trend after the introduction of the Tier IV regulations. Our customers want smarter, better performing machines, and we have to deliver,” said Marco Tacke, product marketing manager at Danfoss Power Solutions.

A more electronic machine
Similar to the transformation of modern automobiles, the shift toward more electronics is allowing manufacturers to deliver these intelligent, high-performing machines to the worksite. Gone are the days of relying solely on an operator’s skill to maximize the productivity and efficiency of off-highway machines. Onboard electronics and software allow for the monitoring of multiple variables in a system at once, and automatically make changes to maximize the efficiency and improve the productivity of the system. In addition, real-time feedback can be provided to the operator while up-to-date machine information is being sent to the home office for monitoring and evaluation.

The introduction of electronics has proven beneficial not only in the area of productivity, but also performance. In the past, power management was limited to satisfying the cooling needs of the vehicle based solely on coolant temperature. Tier IV emissions requirements forced manufacturers to rethink the way cooling is supplied to their systems. Now, with the use of smart control systems, variable hydraulic fan drive systems decouple the fan speed from engine speed, and deliver precisely the right amount of cooling to the system. In addition, distributed cooling systems with multiple coolers are now being implemented to save additional power by separating the cooling of charge air from the cooling of the hydraulic fluid and engine coolant.

Smart control systems like the Fan Drive Subsystem application block within Danfoss’ PLUS+1 development platform have made the independent control of these systems simple. In the PLUS+1 Guide software environment, designers can quickly develop and configure a control system specific to their application using pre-defined, ready-to-implement parameters. Additionally, with the onboard electronics, the cooling system’s power management solution can also include inputs to help prevent engine stall at peak load and overspeed during braking events.

The PLUS+1 Development Platform provides opportunities to find new efficiencies in systems unlocked by electronic control. “Precise and intelligent system control achieved through use of this technology results in overall machine efficiency gains while maintaining or increasing operator and vehicle productivity,” said Kevin Lingenfelter, advanced systems engineer at Danfoss Power Solutions.

Increase efficiencies, decrease costs

Smart systems and controls also prove to increase efficiency and decrease cost when implementing intelligent engine speed control. On many machines, it is common to use a constant engine speed while performing work cycles; however, for many applications, the result is wasted energy. By recognizing the needs of the work cycle, smart systems can manage engine speed accordingly and, in turn, improve fuel efficiency. Figure 1 shows a typical work cycle for a backhoe loader. Notice during the work cycle where actual engine speed is higher than the minimum required speed. By using Danfoss’ Work Function Control (WFC) subsystem application software, the engine speed can be better matched to the actual speed required to perform the desired work, as shown in Figure 2—resulting in increased efficiency and fuel savings. Machine testing showed a 15 to 20% reduction in fuel consumption with no compromise in productivity.

In addition to intelligent engine control, the WFC subsystem application software also has preprogrammed software blocks that can provide active dampening for smooth motion control, load operation envelope control, electronic flow sharing and electronic torque limiting. These software blocks can provide additional capabilities for the designer to improve productivity, performance, efficiency and operator comfort.

Data tracking means smart operating decisions
Finally, electronic-enabled machines are allowing manufacturers to provide more information to operators as well as supervisors and owners. Displays can be used to provide simple information, such as system status or efficiency, to help users make smarter decisions about operating the vehicle. Software solutions can also be developed to allow operators to adjust characteristics of the machine to match their preferences.

With telematics now becoming commonplace in off-highway machines, machine-specific information can be delivered to almost any web-enabled device. While telematics solutions can deliver seemingly unlimited amounts of information about a machine, even basic information such as location, hours, idle time and fuel consumption can help supervisors or owners better understand their machine useage. Telematics also offers the ability to troubleshoot the equipment remotely and supply technicians with valuable information before they leave on a service call.

Danfoss’ Telematics Solutions, launched late last year, offers the latest in telematics technology. It integrates into the PLUS+1 platform without the need of specific software adaptions. Being a plug-and-perform solution, instead of code-and-compile, allows existing machines to be retrofitted without the need for changing a single line of code. In addition to many of the standard telematics features, it will allow users to remotely deliver updated software or parameters directly to machines through the PLUS+1 Service Tool. This feature combined with remote data logging and debugging will enable manufacturers to reduce their time to market. Remote diagnostics and services will allow owners and fleet managers to reduce downtime and increase safety on the worksite.

“By using more electronics, sensors and electrohydraulic controls in the off-highway marketplace, manufacturers will continue to deliver increasingly intelligent, high performance machines to the worksite. Improved productivity, increased efficiency and better control are just a few of the benefits operators will experience as a result,” said Tacke.

“The information collected from these machines is providing key data to help owners better manage their fleets and, in the end, deliver more to the bottom line. These benefits matched with the new technology development and improvements are moving us to a more digital worksite every day.”

Danfoss
www.danfoss.com