Knock detector using optical fiber thermometer
First Claim
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1. A knock detector for detecting the presence of knock in an internal combustion engine comprising:
- (a) temperature sensing means located in an engine cylinder of the internal combustion engine for sensing variations in temperature therein;
(b) fourier analysis means coupled to said temperature sensing means for determining the fourier components of the variations in temperature within said engine cylinder over a combustion cycle; and
(c) detector means for determining when predetermined ones of said fourier components of the measured temperature variations vary with respect to a standard set of levels by a preset amount thereby indicating that a knock condition exists within said engine cylinder.
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Abstract
A knock detector for an internal combustion engine includes an optical fiber thermometer that senses variations in heat flow within an engine cylinder. The optical fiber thermometer includes a black body emitter disposed inside the cylinder which is heated by combustion gases to provide an optical output. The optical output is converted to an electrical signal whose fourier components are analyzed to determine whether a knock condition exists.
37 Citations
24 Claims
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1. A knock detector for detecting the presence of knock in an internal combustion engine comprising:
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(a) temperature sensing means located in an engine cylinder of the internal combustion engine for sensing variations in temperature therein; (b) fourier analysis means coupled to said temperature sensing means for determining the fourier components of the variations in temperature within said engine cylinder over a combustion cycle; and (c) detector means for determining when predetermined ones of said fourier components of the measured temperature variations vary with respect to a standard set of levels by a preset amount thereby indicating that a knock condition exists within said engine cylinder. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A knock detector for detecting the presence of knock in an engine cylinder of an internal combustion engine comprising:
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(a) temperature sensing means comprising at least one black body emitter situated inside said engine cylinder and coupled to an optical detection circuit by an optical fiber, said optical detection circuit having an output signal representing temperature within said engine cylinder; and (b) signal processing means for examining at least one parameter of said output signal to determine if a knock condition exists within said engine cylinder, wherein said signal processing means comprises fourier analysis means for dividing said output signal into selected ones of its fourier components and for providing a knock detection signal when the amplitudes of said fourier components differ from amplitudes representing idealized fourier components by a predetermined amount. - View Dependent Claims (12, 13)
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14. A method of detecting the presence of knock within an engine cylinder of an internal combustion engine comprising the steps of:
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(a) sensing variations in temperature within the engine cylinder over a combustion cycle; (b) converting said variations in temperature to an electrical signal; (c) dividing said electrical signal into predetermined ones of its fourier components; (d) comparing the fourier components obtained during step (c) with a set of preset thresholds; and (e) providing a signal indicating the presence of knock when said fourier components exceed said thresholds. - View Dependent Claims (15, 16)
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17. A system of monitoring the presence of knock in an internal combustion engine, comprising:
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a temperature sensor positioned within a cylinder of said internal combustion engine, said sensor being characterized by providing an electrical signal outside of said cylinder that varies in proportion to temperature within said cylinder, electronic means receiving said temperature proportional electrical signal for measuring a level of components thereof within at least one defined frequency band that includes only one harmonic of a combustion frequency of the engine, and means receiving the measured signal level for comparing said level with a characteristic level of said electrical signal when the engine is known to be operating without knock, thereby to provide an indication when engine knock is present. - View Dependent Claims (21, 22)
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18. A system of monitoring the presence of knock in an internal combustion engine, comprising:
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a temperature sensor positioned within a cylinder of said internal combustion engine, said sensor being characterized by providing an electrical signal outside of said cylinder that varies in proportion to temperature within said cylinder, means responsive to operation of the engine for providing a control signal proportional to a frequency of combustion within said engine cylinder, electronic means receiving both said electrical signal and said control signal for measuring levels of the temperature proportional electrical signal within a plurality of non-overlapping frequency bands related to said combustion frequency, and means receiving the measured signal levels within the plurality of electronic signal frequency bands for comparing said levels with characteristic levels thereof, thereby to provide an indication when engine knock is present. - View Dependent Claims (19, 20)
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23. A method of detecting the presence of knock within an engine cylinder of an internal combustion engine, comprising the steps of:
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(a) observing from outside said cylinder a radiation signal thermally generated within said cylinder; (b) converting the observed radiation signal into an electrical signal proportional thereto; (c) dividing said electrical signal into specific fourier components related to a frequency of combustion within said engine cylinder and maintaining said fourier components in relationship to the frequency of combustion as the engine speed varies; (d) comparing the fourier components obtained during step (c) with a set of preset thresholds; and (e) providing a signal indicating the presence of knock when said fourier components exceed said thresholds. - View Dependent Claims (24)
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Specification