Article - February 1, 2021

Electrification in the field

The transition of mobile machinery and off-highway equipment away from fossil fuels may be a long-term goal, but electrification is already delivering real benefits in the sector

Is the era of the internal combustion engine coming to end? Under pressure to reduce harmful emissions, the automotive industry is already gearing up for a large-scale transition to electric power. Now attention is turning to other mobile machinery applications, especially the types of heavy-duty equipment widely used in agriculture, forestry, construction and municipal roles.

In one survey of the mobile machinery sector, more than 70 percent of respondents said they thought electric power would eventually become more prominent than fossil fuel power, and over 86 percent said that electrification is already becoming a more important topic for their organisations.

Despite the growing interest in the topic, however, real progress in the electrification of mobile machinery has been slow. Indeed, more than 40 percent of respondents to the same industry survey said that electrification had not yet had a real impact on their companies.

Barriers to wholesale electrification include the high cost and limited availability of batteries with sufficient capacity to support demanding real-world operating cycles. In some sectors, access to suitable charging infrastructure can be another important issue.

Taking charge of change

Increasingly, however, machine makers and users are recognising that even partial electrification of equipment has the potential to deliver significant cost, reliability and operational benefits. That’s driving renewed interest in hybrid architectures, where a combustion engine generates electric power for the machine, sometimes in combination with on-board battery storage. The Power Take-Off from the engine or the hydraulic output can be replaced by an electrical output. That approach means electromechanical actuators are becoming a real alternative to the hydraulic systems that have dominated the mobile machinery sector for decades, especially for high loads.

Let’s look at those potential benefits in detail. First, there’s efficiency and stability. Electromechanical systems only consume the requested energy per cylinder or actuator when they are actually being used, and they can be up to 80 percent efficient in turning input power into useful work. Compare that to the 44 percent end-to-end efficiency that is typical of a hydraulic power system. Greater energy efficiency means lower CO2 emissions, but also translates into significant cost savings for operators. For Internal Combustion Engine vehicles, the fuel costs of fully electromechanical mobile machines can be half those of their diesel-powered counterparts. For Battery Electric vehicles, the batteries on board could be halved in size and have quicker charging time. In addition, the recovery of electricity increases the efficiency even further, enabling a reduction in battery costs.

Electric power can offer other environmental advantages too. Machines with on-board energy storage can be designed to operate under electric power alone for parts of their operating cycle. That makes them much quieter, a real benefit for equipment operating overnight in urban areas, for example. And because electromechanical systems don’t use high pressure oil, the risk of accidents or pollution from fluid leaks is eliminated. That’s a boon for vehicles working in our cities or in clean indoor spaces, but also for agricultural machines and for any equipment that operates in sensitive natural environments.

Performance premium

Then there’s the cost of keeping equipment running. Modern electromechanical actuators offer very high levels of reliability and long operating lifecycles with very little requirement for routine maintenance. Even if an actuator does fail in service, replacement is usually a simple case of swapping the component and connecting a few cables. A problem with a hydraulic system, by contrast, often requires specialist maintenance expertise and involves extensive downtime.

Electric power offers important productivity benefits. The speed, position and acceleration of electromechanical actuators can be precisely controlled over their full range of motion, without the need for elaborate additional control equipment. That capability drives up machine performance and is a critical enabler for new generations of smart machines designed for a wider range of tasks and operating conditions, or which adapt their behaviour dynamically under computer control. The communication between electro-mechanical actuators and the electronic control unit of the equipment uses simple wires Input / output or Bus communication like CANBus.

Electromechanical actuators are also ready for the industrial Internet of Things (IoT). While collecting performance and reliability data from hydraulic or pneumatic systems requires complex additional sensors, electromechanical systems offer machine manufacturers and operators straightforward access to high quality data, suitable for fleet monitoring applications or as the basis for predictive and condition-based maintenance approaches. It is even more true for autonomous vehicles or robots that need reliable systems and on-board diagnostics.

Making the switch without compromise

Designing and specifying electromechanical systems in mobile machinery is becoming much more straightforward too. Manufacturers like Ewellix have used their years of development, testing and customer support experience to produce a wide range of standard actuator systems specifically designed for the rigours of mobile applications. The key characteristics of these systems include DC motors, for ease of integration with batteries and on-board power generation equipment, a wide operating temperature range as high levels of sealing and corrosion protection.

The Ewellix CAHB22E series, for example, is ideal for the replacement of pneumatic or light hydraulic cylinders with bore 32 mm or 40 mm in medium duty cycle applications. These actuators are used for decades in a range of mobile machinery applications for auxiliary functions with adjustment or lifting, including road pavers, road sweepers, combine harvesters and lawn mowers. The units are virtually maintenance-free, push and pull 10 000N, 20 000N self-locking with an IP grade 66M/69K secured by a vent. Designed to operate in temperatures from -40 to 85°C at up to 20 percent duty cycle, CAHB 20E, 21E and 22E actuators feature robust metal gears, high holding force, speed up to 55mm/s, mechanical over-load protection, and a manual override option. The CAHB-10 actuator series also feature robust metal gears in a very compact design to push or pull up to 1500N.

Some of the latest electromechanical systems use highly modular designs, giving OEMs tailored performance in a cost-effective and well-integrated package. For example, the new Ewellix CASM-100 modular electric cylinder platform has been developed to address a wide range of heavy machinery applications. In a departure from previous systems, the new range extends its modularity to the base component level. Within each module, the customer can select the internal components to build a custom-like solution as standard with the best performance/cost ratio. Several options are available, making CASM-100 the ideal solution for replacing hydraulics in high load applications, covering loads up to 8 tonnes in medium to high duty cycle applications for work functions. The CASM-100 electromechanical actuator allows to lift a platform without a hydraulic system and regenerate the energy during the lowering movement. Fully electric Aerial Work Platform scissor-lifts for construction and maintenance are already equipped with CASM-100 electromechanical actuators.

Taking a “more electric” up to “Electric End to End” approach to the design of mobile equipment offers an array of immediate benefits for OEMs and users alike. By beginning the shift to electric power today, machine designers are putting themselves in the best possible position to support the transition to a future world of clean, quiet and efficient fully electric machines.