Hydraulic dissolved air measurement system and method

A method comprising:

• receiving a hydraulic fluid sample from a hydraulic reservoir into a measurement chamber of a testing device, wherein the testing device includes a housing and a piston that is movable relative to the housing, and wherein the housing and the piston define the measurement chamber;
• controlling, via one or more processors, a piston actuation device that is operatively coupled to the piston to move the piston to expand the measurement chamber to an expanded state after receiving the hydraulic fluid sample in the measurement chamber;
• determining, via the one or more processors, a volume change value that represents a volume increase of the measurement chamber based on movement of the piston;
• receiving a pressure value generated by a pressure sensor coupled to the testing device, wherein the pressure value represents the pressure within the measurement chamber in the expanded state;
• and
• determining, via the one or more processors, a dissolved air content (DAC) of the hydraulic fluid sample based on the pressure value and the volume change value.

An aircraft comprising:

• a hydraulic system including a hydraulic reservoir and a pump;
• and
• a dissolved air measurement system comprising:
• a testing device including a housing and a piston that is movable within the housing, the housing and the piston defining a measurement chamber that is configured to receive a hydraulic fluid sample from the hydraulic reservoir;
• a pressure sensor coupled to the testing device and configured to measure a pressure within the measurement chamber;
• a piston actuation device operatively coupled to the piston and configured to move the piston;
• and
• a controller communicatively connected to the pressure sensor and the piston actuation device, wherein the controller is configured to:
• control the piston actuation device to move the piston to expand the measurement chamber to an expanded state after the hydraulic fluid sample is received in the measurement chamber;
• determine a volume change value that represents a volume increase of the measurement chamber based on movement of the piston;
• receive a pressure value from the pressure sensor that represents the pressure within the measurement chamber in the expanded state;
• and
• determine a dissolved air content (DAC) of the hydraulic fluid sample based on the pressure value and the volume change value.