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The transmission of fluidborne pressure and flow pulsations through a hose assembly is dominated by a four-port transfer matrix equation. The potential of pulsation attenuation in the assembly is then related to the four parameters of the matrix by the concept of “Transmission Loss”. The paper presents the development of an accurate test system, based on the “Four Sensors/Two Systems” method, for measuring the transfer matrix and transmission loss of hose assemblies. Particular attention is paid to the solutions to some technical problems encountered during the development and measurement. Then presented is the application of the system to various types of flexible hose with or without tuning cables used in power steering hydraulic systems. The measurements are very valuable for developing the best tuning cable and hose devices, quieter power steering systems as well as the hoses used similarly in other fluid power systems.

A summary of several existing methods for measuring the speed of sound in the fluid in a pipe is presented first. Their basic principles, advantages and limitations are compared. Those methods are good enough for the fluid in rigid pipes, but not for the fluid in a compliant fluid pipe system. The paper proposes an accurate measuring method using a system for determining the transfer matrix parameters of fluid power components. This method can provide satisfying results for the fluid contained not only in a rigid pipe but also in other softer/deformable pipes, such as flexible rubber hoses.

A tuning cable and hose device, i.e. a flexible metal tuning cable placed coaxially inside a section of hose, is usually used in power steering hydraulic circuits to reduce pressure pulsations in the circuits. To evaluate the fluidborne noise attenuation characteristics of tuning cable and hose devices correctly, a new evaluation method, based on the experimental determination of transmission loss of the tuning cables and hoses, is proposed here. The effectiveness of the method and test system are confirmed. The results obtained are valuable for design optimization and theoretical modeling of hydraulic power steering systems and other similar hydraulic systems.