Method and systems for controlling fluid temperature in a hydraulic system of an aircraft powered by an HPP

A hydraulic system for an aircraft comprising

• a hydraulic power pack including a motor, a hydraulic fluid reservoir and a hydraulic pump,
• at least one hydraulic consumer,
• a high-pressure supply line configured to supply the at least one hydraulic consumer with hydraulic fluid under higher pressure,
• a low-pressure return line configured to return hydraulic fluid under lower pressure from the at least one hydraulic consumer,
• a temperature sensor configured to sense a fluid temperature of the hydraulic fluid,
• a heating device including a short-cut hydraulic line connecting the high-pressure supply line with the low-pressure return line and a heater valve configured to open and close the short-cut hydraulic line,
• an isolation valve configured to isolate the at least one hydraulic consumer from the hydraulic power pack, and
• a control and monitoring unit configured to:
• control the heater valve depending on the fluid temperature,
• control the hydraulic power pack to execute a heating function for heating the hydraulic fluid within the hydraulic power pack by operating the hydraulic pump, and
• opening the short-cut hydraulic line while the at least one hydraulic consumer is isolated from the hydraulic power pack by the isolation valve.

A hydraulic power pack for a hydraulic system of an aircraft comprising:

• a motor,
• a hydraulic fluid reservoir,
• a hydraulic pump,
• a hydraulic output port configured to supply a hydraulic consumer with hydraulic fluid under higher pressure,
• a hydraulic input port configured to receive hydraulic fluid under lower pressure returning from the hydraulic consumer,
• a heating device including:
• a short-cut hydraulic line between the hydraulic output port and the hydraulic input port,
• a heater valve configured to open and close the short-cut hydraulic line,
• a temperature sensor configured to sense a hydraulic fluid temperature, and
• an isolation valve configured to isolate the hydraulic output port from the hydraulic pump, and
• a control and monitoring unit configured to:
• control the heater valve in dependence from the hydraulic fluid temperature, and
• control the hydraulic power pack to execute a heating function for heating the hydraulic fluid in hydraulic power pack by running the hydraulic pump and opening the short-cut hydraulic line while the hydraulic output port is isolated from the hydraulic pump by the isolation valve.