Oil level sensing and fault detection
An oil level measurement system for an aircraft engine includes a magnetic float disposed in the aircraft engine, a first sensor ladder configured for sensing a position of the magnetic float, and a second sensor ladder configured for sensing a position of the magnetic float. A controller is configured to determine an oil level of an engine based on an engine status signal, a first signal from the first sensor ladder, and a second signal from the second sensor ladder. An oil level sensing method for measuring an oil level within an aircraft engine when the aircraft engine is off includes comparing a first signal from a first sensor ladder with a second signal from a second sensor ladder, indicating a fault when the first signal is different from the second signal, and determining an oil level of an aircraft engine when the first signal matches the second signal.
1 . An oil level measurement system for measuring an oil level within an aircraft engine, the system comprising:
a magnetic float disposed in the aircraft engine;
a first sensor ladder configured for sensing a position of the magnetic float;
a second sensor ladder configured for sensing a position of the magnetic float;
an aircraft engine status signal indicative of a current state of the aircraft engine;
a controller configured to receive the aircraft engine status signal, a first signal from the first sensor ladder, and a second signal from the second sensor ladder, wherein the controller is configured to determine an oil level of the aircraft engine based on the aircraft engine status signal, the first signal, and the second signal, such that when the aircraft engine is off a static oil level check is performed and when the aircraft engine is starting or running a dynamic oil level check is performed; and
a notification subsystem communicatively coupled to the controller, wherein the notification subsystem is configured to notify a user of a fault when the first signal is determined by the controller to be different from the second signal, and the notification subsystem comprises a display device configured to display an oil quantity only when the oil level is static.
2 . The oil level measurement system of claim 1 comprising a float guide, wherein the float guide comprises a vertical orientation configured to guide movement of the float along a vertical direction.
3 . The oil level measurement system of claim 2 , wherein the float guide comprises a track configured to receive the magnetic float such the magnetic float is constrained to move vertically along the track.
4 . The oil level measurement system of claim 2 , wherein the float guide comprises a rod and the magnetic float comprises a channel configured to receive the rod such that the magnetic float is constrained to move vertically along the rod via the channel.
5 . The oil level measurement system of claim 1 , wherein the first sensor ladder and the second sensor ladder have a similar architecture and construction to provide redundancy for increased reliability.
6 . The oil level measurement system of claim 1 , wherein the first sensor ladder comprises an electrical circuit having a plurality of reed switches arranged electrically in series and the second sensor ladder comprises an electrical circuit having a plurality of reed switches arranged electrically in series.
7 . The oil level measurement system of claim 6 , wherein each reed switch from the first sensor ladder and the second sensor ladder is configured to open or close based on a proximity with the magnetic float.
8 . The oil level measurement system of claim 7 , wherein the first sensor ladder and the second sensor ladder each comprise a plurality of resistors paired with a respective reed switch such that a resistance of the electrical circuit changes as a vertical position of the magnetic float changes.
9 . The oil level measurement system of claim 8 , wherein each reed switch from the first sensor ladder and the second sensor ladder is positioned vertically to correspond with a known oil level within the aircraft engine such that the first signal and the second signal each correspond with the known oil level.
10 . The oil level measurement system of claim 1 , wherein the controller is further configured to check that the first and second signals match when the aircraft engine is off, and when the first and second signals match the controller is configured to subsequently determine the oil level based on the first and second signals.
11 . The oil level measurement system of claim 10 , wherein the controller is further configured to inhibit determining the oil level based on the first signal and the second signal when the aircraft engine is starting or running.
12 . The oil level measurement system of claim 1 , wherein the controller is further configured to perform a dynamic sensor check by determining whether a position of the magnetic float is actively changing based on the first signal and the second signal when the aircraft engine is starting or running.
13 . The oil level measurement system of claim 12 , wherein the controller is further configured to provide a notification signal to the notification subsystem indicative of a successful dynamic sensor check when the position of the magnetic float is actively changing and the aircraft engine is starting or running.
14 . The oil level measurement system of claim 12 , wherein the controller is further configured to provide a notification signal to the notification subsystem indicative of a fault that the magnetic float may be stuck when the position of the magnetic float is not actively changing and the aircraft engine is starting or running.