Control of bulk modulus of oil in hydraulic systems

In view of requirements for better position accuracy, response time and stability of hydraulic system, it is more important than ever to pay attention to bulk modulus of hydraulic oil. In this paper, the effects of the bulk modulus of hydraulic oil on system performance and the entrapped air on bulk modulus have been analyzed. A method of online vacuum degassing in a sealed system has been used to increase the effective bulk modulus of hydraulic oil, and a device has been developed to measure oil bulk modulus online. The experimental results show that the bulk modulus of hydraulic oil can be controlled in real system effectively by the method mentioned above.