There are many discussions regarding electrification in the fluid power industry right now, especially electro-hydraulic pump units. With all the buzz around this technology, it is difficult to understand what the advantages are and why go through the trouble of integrating electro-hydraulics into your mobile machine. If the benefits are not clear, most folks tend to dismiss the claims as being marketing hype and continue using antiquated methods despite the known shortcomings. Electro-hydraulic pumps are most known for allowing for a major increase in efficiency. What is less known is, electro-hydraulics also offer a huge gains in simplicity, capability, and tuning. In this article we will touch on some of the key points of why manufacturers are switching to electro-hydraulics other than energy efficiency gains.
Traditional Hydraulic components
Every hydraulic system is different, however, they all have the same basic components that make up the system. Each includes a prime mover (diesel or electric), pump, valves, reservoir, oil cooler, and actuators. Each of these components are potential failure points within the system. The components themselves, or the hoses and fittings between them can fail. While some of these components, such as actuators, cannot be omitted, electro-hydraulics combine many of the components, and make others obsolete.
An integrated electro-hydraulic pump is an electric motor, motor controller, and pump all in one unit. The system is powered from an AC or DC power source which opens opportunities for hybrid or zero emission battery power but does not necessarily eliminate a diesel engine. It is inherently more efficient than a traditional system for several reasons. Electro-hydraulics operate in power-on-demand mode and only use energy when work (pressure/flow) is needed. In addition, electro-hydraulics have built in directional and proportional control eliminating the need for manifolds and inefficient directional valves. Improved efficiency means the system generates far less heat. As a result, the oil cooler is omitted. In addition, a simple gear pump can be used instead of a complicated and expensive variable speed pump.
- Electro-hydraulic systems run more efficiently and cooler than traditional systems
- Electro-hydraulics integrate or omit components in a traditional hydraulic system
- Electro-hydraulics can utilize hybrid or zero emission electric drivetrains
Artisan hydraulic troubleshooting
Traditional hydraulic systems are not easy to troubleshoot. There are many components that have potential to fail over time. A component failure may manifest itself in ways that are not inherently obvious. Each component has an affect on the other components and can create a difficult troubleshooting scenario that may need the expertise of a seasoned hydraulics technician to solve.
Electro-hydraulics have self-diagnostic capabilities that are changing the way hydraulics are designed, maintained, and repaired. Onboard diagnostics can monitor voltage, current, rpm, power output, temp, pressure, flow, vibration, and many other metrics. This data is used for internal monitoring of the system for optimal performance as well as alerting operators of errors, fault codes, and maintenance issues. Datalogging capabilities can detect changes over time that can show pump or bearing wear. This allows for planned maintenance to be done to avoid catastrophic failures that can cause extended downtime.
- Traditional hydraulics can be difficult to troubleshoot
- Electro-hydraulic systems are self-diagnostic with multiple sensors collecting data continuously
- Self-diagnostics detect issues earlier and allow for planned maintenance to avoid catastrophic failures
Some of the latest electro-hydraulic systems are almost plug-and-play, right out of the box. Plug in your power supply, communication interface, a/b hydraulic hoses, and you are ready to go. Simple configuration tuning can be done digitally from the user interface. Of course, if you are upgrading an entire machine it is a bit more involved than that. However, this is opening a new era of fluid power that resonates with a new generation of engineers, and technicians, in the fluid power industry. As more of the seasoned fluid power veterans are retiring, focus is on creating products that make fluid power integration easier. This is accomplished by using components that can be applied to a wider array of systems, shortening design cycles, and bring-up time.
- Some electro-hydraulic systems are plug and play right out of the box
- Simple configuration tuning available via the user interface
- Electro-hydraulics allow the creation of products that make fluid power integration easier
Full system Integration
Now that we have covered some of the positive aspects of electro-hydraulic power units, let’s discuss some of the hurdles. If it was simple to switch to electro-hydraulics the entire industry would have already done it. Unfortunately, upgrading an entire machine to electro-hydraulics means looking at the complete hydraulic system and potentially drivetrain system to take full advantage of the benefits of electro-hydraulics. Most hydraulic equipment has been designed and incrementally tuned over decades. Changes to the system can be hard to get approval. However, if a piece of equipment is undergoing a major redesign (for emissions regulations for example) or is a newly designed piece of equipment, then it may be a great opportunity to move to electro-hydraulics. Additionally, electro-hydraulics can be integrated at different levels. For instance, an electro-hydraulic pump unit can be added to an existing hydraulic system, as is, without changing anything on the hydraulic side. This would add power-on-demand functionality and efficiency benefits without forcing a complete hydraulic system redesign.
Cost of entry
Cost of entry is another obstacle often discussed. The individual cost of the electro-hydraulic pump unit will be more than traditional pumps. A high tech electro-hydraulic pump may be overkill for some applications, such as a tilt trailer. However, electro-hydraulics are becoming cheaper as they gain momentum in fluid power. In addition, for more demanding applications, the money and time saved in the overall system by eliminating valves, manifolds, multiple sensors, oil coolers, hoses, fittings, and of course fuel consumed will be much cheaper than traditional hydraulics.
Preconceptions of new technology are hard to overcome in this industry. Electronics have long had a negative reputation for being difficult to integrate as well as unreliable. That may have been true 25 years ago, but today electronics are everywhere, including applications considered harsh and demanding. They have become much simpler to integrate via touch screen interfaces and preprogrammed configurations. Modern electrical systems are spec’d appropriately and undergo extensive environmental certification testing before logging hours in the field. If they are integrated properly, there should be no reliability issues with electronics.
While electro-hydraulics are catching on because of their efficiency gains and ability to lower emissions, there are also performance and functionality benefits that add tremendous value. As more OEM’s integrate electro-hydraulics, we expect to see the technology used in ways that have not been thought of yet. While Diesel might be around for another 10 or 20 years, electro-hydraulics are paving the way to a cleaner future with advanced technologies that are available now.