Hydraulic systems are key to almost every type of off-highway vehicle heavy component, like engines, brakes, and lifting mechanisms. They offer the ability to apply more force and move heavier loads without the need for gears or pulleys, as well as standing up to very harsh environments and extreme mechanical stresses. However, with the growing electrification of off-highway vehicles, some manufacturers may choose to do away with hydraulics entirely and replace them with electric drives.
Electrified off-highway vehicles can help manufacturers and end users meet strict emission legislation and standards, but they face their own unique challenges. A machine must be able to perform a full day’s work on a single charge; however, runtime on a single charge is too short, and adding more battery power adds expense. Original equipment manufacturers (OEMs) must balance battery cost with the power and range requirements of the machine without creating a price-prohibitive product. The deployment of an integrated hybrid electric hydraulics system that works together in harmony can recover energy and store it, enabling the electric motor to effectively run as a generator.
Optimisation of hydraulics to improve machine runtime includes changes to the hydraulic architecture and technologies such as gravity lowering, independent metering, and zonal systems, which focus on driving out the inefficiencies of hydraulics. Integrated systems that combine valves, pumps, and electric motors can maximise performance and efficiency. Machines can save energy by reusing flow and pressure that’s already in the system and avoiding additional pump flow, saving energy via gravity lowering. Using independent metering valves, each work port can operate independently of the other, enabling more efficient and better control of services that transition between passive and overrunning states. Energy recuperation entails using existing overrunning energy in the system to backdrive an electric motor for battery charging, increasing runtime.
Dr. Enrique Busquets, Director of Engineering at Bosch Rexroth, will be a keynote speaker at DZOM EXPO, our upcoming event where industry leaders and solution providers will gather to discuss the latest innovations in the off-highway vehicle industry. He will be giving an in-depth presentation titled ‘Hydraulic Systems for Electric or Hydrogen-Powered Working Machines’ where he will share his valuable insights after his many years of study and experience in the field. Writing in an article published on SAE.org in 2022, Dr. Busquets stresses that electrification in off-highway applications must make optimum use of both next-gen electric and hydraulic technology. He says, “Hydraulics has a vital role in these (battery-electric heavy-duty mobile) machines due to the reliability and power density that only hydraulics can supply,” espousing the importance of combining and adapting hydraulic systems to work with electric off-highway vehicles.
In conclusion, the shift towards electrification introduces both opportunities and challenges for off-highway vehicles. Electrified vehicles promise environmental benefits and adherence to stringent emissions standards, but they require careful balancing of battery life, cost, and performance. The integration of hybrid electric-hydraulic systems is a promising solution to enhance energy efficiency and extend operation time. For the opportunity to hear Dr. Busquets’ insights on hydraulic systems for zero-emission off-highway vehicles and learn from many other industry experts imparting their knowledge from their years of professional experience, book your pass to the DZOM EXPO taking place at the Donald E. Stephens Convention Centre in Chicago, IL, on December 3–4, 2024.
For more information, visit our website or email us at info@innovatrix.eu for the event agenda.
Read this article over on the Innovatrix blog and discover our other articles and events.