Patent ID: 8218147
Filing Date: 2012-07-10
Classification: G01N

Abstract:
1. A method comprising: interrogating a working engine fluid in-situ on the engine with electromagnetic (EM) radiation through a first conduit at a wavelength of interest; detecting a response of the working engine fluid to the radiation through a second conduit; interrogating the working engine fluid with EM radiation through the first conduit at a diagnostic wavelength; detecting a diagnostic response of the working engine fluid to the radiation through the second conduit, and generating a diagnostic signal in response to the diagnostic response; generating a diagnostic signal in response to the diagnostic response; and generating a composition indicator signal representative of an amount of a constituent of the working engine fluid, wherein the generating the composition indicator signal is in response to a corrected composition indicator signal, the method further comprising determining the corrected composition indicator signal according to: wherein CCIS comprises the corrected composition indicator signal, Active comprises the composition indicator signal, Inactive comprises the diagnostic signal, and Dark comprises a detected response at a time when the working engine fluid is not being interrogated with EM radiation.