Integrated active vibration cancellation and machine diagnostic system
AssigneeFord Motor Company
InventorsTimothy A. Tiernan, Earl R. Geddes, Mark L. Mollon
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Abstract
A machine analyzer is connected to an active vibration cancellation system in order to identify the operating status of the moving machinery while using a minimum of additional parts and taking advantage of signal processing already occurring in the active vibration cancellation system. A preferred embodiment employs a neural network pattern classifier in connection with detecting operating states such as cylinder misfires in an internal combustion engine.
Claims21
A method for detecting a status of a machine having relatively moving parts wherein operation of said machine creates vibrations, said method comprising the steps of:
- actively cancelling said vibrations with a transducer controlled by an adaptive controller;
- sensing residual vibrations remaining after said active cancellation;
- adapting said adaptive controller in response to said residual vibrations;
- and
- comparing the adapted state of said adaptive controller with predetermined states to classify said status.
Apparatus comprising:
- a machine having relatively moving parts wherein operation of said machine creates vibrations;
- transducer means for combining counter-vibrations with said vibrations;
- sensor means for sensing residual vibrations remaining after said combination of vibrations and counter-vibrations;
- controller means coupled to said transducer and said sensor means for actuating said transducer and adapting to a controller state which minimizes said residual vibrations;
- and
- comparing means for comparing said adapted controller state with predetermined states to classify a corresponding operating status of said machine.
An integrated vehicle system for actively cancelling exhaust noise in an exhaust conduit of an engine and for analyzing performance of said engine, comprising:
- a cancellation system including:
- input transducer means for producing an input signal proportional to a sound pressure wave at a first location in said conduit;
- output transducer means for producing a cancelling pressure wave at a second location in said conduit in response to an output signal, said first location being between said second location and said engine;
- error transducer means for producing an error signal proportional to a sound pressure wave at a third location in said conduit, said second location being between said first and third locations;
- and
- adaptive filter means responsive to said input signal and said error signal for producing said output signal, said adaptive filter means including a plurality of digital filter coefficients having digital values determined in response to said error signal;
- and
- performance monitor means coupled to said cancellation system to classify a performance parameter of said engine in response to at least one signal from said cancellation system.
A method for analyzing performance of a combustion engine, said engine having an exhaust conduit and an active exhaust noise cancellation system coupled to said exhaust conduit, said cancellation system including an adaptive filter implemented with digital filter coefficients, said method comprising the steps of:
- sensing an input sound pressure wave at a first location in said exhaust conduit;
- determining a cancelling wave with said adaptive filter which is inverse to said input sound pressure wave;
- injecting said cancelling wave into said exhaust conduit at a second location displaced from said first location in the direction of exhaust flow;
- sensing an error sound pressure wave at a third location displaced from said second location in the direction of exhaust flow;
- adapting-said adaptive filter by modifying said digital filter coefficients to minimize said error sound pressure wave;
- and
- processing said digital filter coefficients to classify said engine performance.
Dependencies are inferred from the claim text.