German scientists develop new micro-sensor to directly monitor temperature, pressure, and lubricant thickness in hydraulic pumps

German scientists are developing a new type of sensor thinner than a human hair, which reportedly can directly measure the temperature, pressure, and lubricant thickness inside hydraulic pumps, enabling early detection of wear signs. The device comes from the Fraunhofer Institute for Surface Engineering and Thin Films (IST). This project, named ThinSor, also involves scientists from Magdeburg University and Aachen University of Applied Sciences.

Features of the New Sensor

The sensor consists of layers a few micrometers thick, directly applied to the pump's valve plate, allowing for monitoring of critical operating conditions without the need for drilling or other modifications. According to researchers, it can measure pressures below 7,252 pounds per square inch (50 MPa), as well as temperature and lubricant thickness. Additionally, the system can improve the efficiency of hydraulic pumps, extend their lifespan, and reduce unexpected downtime.

The sensor operates on the principle that axial piston pumps rely on the back-and-forth movement or slight tilting of pistons on a rotating drive shaft. These pumps are commonly found in hydraulic systems, responsible for moving fluids under high pressure. Their performance primarily depends on the interaction between the rotating cylinder and the stationary valve plate, separated by a thin film of lubricant. The lubricant reduces friction between the two components, preventing rapid wear. However, measuring conditions within this narrow gap during operation remains challenging. Traditional methods often require drilling or modifying pump components to install sensors, which can affect surface interactions and even the measurement results.

To address this issue, the team's sensor is directly installed on the surface of the valve plate. The team stated, "This should allow for high temporal resolution measurements of all three parameters right where they occur, without time-consuming post-processing of components."

Technical Challenges and Solutions

The team faced a significant challenge in measuring contact points at low pressures. The sensor must be capable of detecting pressures below 7,252 pounds per square inch (50 MPa), which is lower than the measurement range of most existing sensors. Therefore, researchers had to enhance the sensor's sensitivity to capture accurate readings without interference from background noise. At the same time, the ultra-thin layers must withstand the immense mechanical forces generated during hydraulic pump operation. The thin-film sensor system is directly applied to the surface of the valve plate. According to the team, this technology can reduce prototype requirements, detect wear signs early, and help engineers plan maintenance to prevent failures.

The institute stated, "The obtained measurement data aims to assist in the more precise design of fluid technology components and validate simulation models and digital twins."

Furthermore, the technology could ultimately support continuous monitoring of both new and old hydraulic systems and may be applicable in areas beyond hydraulic pumps. Researchers summarized in a press release, "Applications involving bearings, gears, and shafts have demonstrated the potential of this technology." The ThinSor project started on June 1, 2026, and is scheduled to conclude on November 30, 2028, with the ultimate goal of making measurement technology applicable for industrial use.

Impact of the New Sensor on Hydraulic Systems

The development of the new micro-sensor is significant for the operation of hydraulic systems. Its ability to directly monitor critical parameters without requiring modifications to equipment not only enhances measurement accuracy but also reduces interference with the system. Additionally, the improved sensitivity of the technology and its early wear detection capabilities will help engineers conduct maintenance more effectively, thereby lowering the risk of failures. The potential applications of this technology are extensive and may drive further advancements in hydraulic technology in the future.