Eaton Aerospace Oil Debris Monitoring Technology. Presentation to the Aircraft Builders Council, Inc. September 26, 2006. Why Monitor Oil Debris?. Engine Wear Predict Engine Failure. Bearing/Gear Life Cycle, Stage One. Run-in stage:
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Presentation to the
September 26, 2006
Initial Wear particles are several hundred microns in size. The size and rate of particle generation decrease as the engine is run in.
Normal Operation Stage:
Debris generation reaches a low rate equilibrium.
Primary Mode – indicated by escalating quantity of of 250–400 micron particles.
Secondary Mode - marked by the generation of much larger debris
110 µg bearing RCF particle
Extruded Rolling Contact Fatigue (RCF) spall flake, ca. 300 µm diameter
Mag Plug (visual inspection)
Chip Collector w/SCV
Electric Chip Detector /SCV (remote indication)
(Quantitative Debris Monitor) Technology
Signal conditioner generates digital pulse when debris particle exceeds preset mass threshold
QDM® (quantitative debris monitoring) inductive debris sensor - generates signal when particle is captured
Debris separation efficiency 75 to 95%
Air separation efficiency > 95%
Oil separation efficiency > 99.8%
3D DMS Design
3D DMS Design
Chips of different mass arrive
Magnetic pole piece
Output pulses for a “small” and a “large” particle
QDM sensor is a passive, magnetic, inductive sensor that collects, retains, and indicates capture of, individual ferromagnetic chips
These “particles” all have the same “size” but their mass differs by >100x
QDM signal conditioner
Pre-set mass threshold
QDM counts discrete particles
Square output pulses to FADEC or EMU
BIT input to sensor
BIT command from FADEC or EMU
1. The signal conditioner indicates chips above a minimum, pre-set mass threshold to reject noise-induced false counts.
2. Limited chip mass classification (two or more mass levels) is possible, but this requires more complex chip alert algorithms.
The QDM Signal Conditioner electronics are simple and contain no software (unless data bus interface or multi-level mass binning is required). Electronics can also be incorporated into FADEC or EMU as Eaton-supplied PC-board or licensed technology.
Approximate size: 4x4x2 in.
MTBF: no field failures in >5 million hours
Per-flight debris count
Cumulative debris count
DMS system fault
EICAS status message
VHF radio downlink via ACARS
Remote Diagnostics program data bases
Debris data trending
DMS Integration and Interfaces on GE90/Boeing 777
QDM Sensors for Smaller Engines - Sump or Scavenge Pump Inlet Installation
QDM sensor with self-closing valve for sump
QDM sensor with valve built into scavenge pump inlet screen
Absence of DMS counts prevented two IFSD’s that would have resulted from false impending-bypass indications due to faulty filter-Δp sensors.
Most airlines no longer perform 500-hour routine sensor inspections originally recommended by Boeing.
Continental has >16,000 hour high-time engines w/o sensor inspection. Routine sensor cleaning not required.
End-to-end BIT detected early harness and other system problems