Servicing monitoring system for mixed fluid-gas shock struts
AssigneeGoodrich Corporation
InventorsAmir M. Fazeli, Adnan Cepic, Susanne M. Reber
Life of this patent
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Abstract
A method and system of monitoring condition of a shock strut senses gas temperature, gas pressure, and stroke of the strut during a landing event. Oil loss is determined based upon a deviation of a transient pressure coefficient derived from transient gas pressures at two different strokes from a nominal coefficient value. Gas loss is determined based upon a temperature adjusted transient gas pressure at a selected stroke and a nominal gas pressure value at the selected stroke.
Claims15
A method of monitoring condition of a shock strut, the method comprising:
- sensing gas temperature, gas pressure, and stroke of the shock strut during a landing event;
- determining oil loss based upon a deviation of a transient pressure coefficient α(s1,s2) derived from a ratio of transient gas pressures Pgas(s1)/Pgas(s2) at two different strokes s1,s2 from a nominal coefficient value α0(s1,s2);
- determining gas loss based upon temperature adjusted transient gas pressure at a selected stroke and a nominal gas pressure value at the selected stroke;
- and
- providing an output indicating need for service of the shock strut based upon the oil loss and the gas loss.
A system for monitoring condition of a shock strut, the system comprising:
- a gas temperature sensor for sensing temperature of gas in the shock strut;
- a gas pressure sensor for sensing pressure of gas in the shock strut;
- a stroke sensor for sensing stroke of the shock strut;
- and
- a digital processor for determining whether the shock strut needs servicing, the digital processor including:
- a recorder that acquires sensed gas temperature, gas pressure, and stroke data from the gas temperature sensor, the gas pressure sensor and the stroke sensor over time and stores the data in a data array;
- a landing detector that determines occurrence of a landing event based upon stroke data in the data array;
- and
- a health monitor that determines oil loss and gas loss based upon the gas temperature, gas pressure, and stroke data from the data array during the landing event;
- wherein the health monitor determines oil loss based upon a transient pressure coefficient α(s1,s2) derived from a ratio of transient pressure data Pgas(s2)/Pgas(s1) at two different strokes s1 and s2, a nominal coefficient value α0(s1,s2) and the sensed gas temperature;
- and determines gas loss based on gas pressure at a selected stroke, the sensed gas temperature and an expected gas pressure value at the selected stroke.
Dependencies are inferred from the claim text.