What kind of fluid is typically used in hydraulic systems?

Hydraulic systems primarily rely on oil-based fluids due to their superior lubricating properties, high viscosity index, and ability to maintain performance over a wide range of temperatures. Oil-based hydraulic fluids can better prevent cavitation and provide consistent transmission of power within the system. They also possess good anti-wear and anti-foam characteristics, which are essential in maintaining the longevity and efficiency of hydraulic components.

Additionally, oil-based fluids are less prone to vaporization under pressure, making them ideal for high-pressure operations typical in hydraulic applications. This characteristic ensures that the hydraulic system can effectively transmit force without losing efficiency.

While water-based, gas-based, and alcohol-based fluids have their own applications, they do not provide the same level of performance and reliability needed in hydraulic systems, particularly in high-load and high-temperature environments. Thus, oil-based fluids are the preferred choice in such systems.