On-board gas composition sensor for internal combustion engine exhaust gases
First Claim
1. An on-board gas composition sensor for an internal combustion engine, for monitoring oxygen content in exhaust gas from the internal combustion engine, the gas composition sensor comprising, in combination:
- light source means for generating excitation light in a preselected wavelength range;
sensor means comprising a sensor body of porous high-temperature fluorescent inorganic oxide ceramic, for emitting an optical fluorescence signal responsive to oxygen content in the exhaust gas upon exposure of the sensor body to the excitation light at 400°
-650°
C.; and
fluorescence detector means for receiving a preselected wavelength range of the optical fluorescence signal which is above the excitation light wavelength range, and for generating an exhaust gas oxygen content output signal in response to the optical fluorescence signal.
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Abstract
An on-board gas composition sensor is disclosed for monitoring oxygen content levels in the exhaust gas of an internal combustion engine. The gas composition sensor includes a light source for generating excitation light, e.g. in the 350-525 nm wavelength range. A sensor body of porous high-temperature fluorescent inorganic oxide ceramic exposed to the exhaust gas emits an optical fluorescence signal responsive to oxygen content in the exhaust gas upon exposure to the excitation light at 400°-650° C. A florescence detector receives the optical fluorescence signal from the sensor means and generates an exhaust gas oxygen content output signal in response. Fiber-optic cable can be employed for transmitting excitation light to the sensor body from a remotely located light emitter. The same or a separate fiber-optic cable can transmit the optical fluorescent signal from the sensor body to the fluorescence detector also at a remote location.
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Citations
20 Claims
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1. An on-board gas composition sensor for an internal combustion engine, for monitoring oxygen content in exhaust gas from the internal combustion engine, the gas composition sensor comprising, in combination:
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light source means for generating excitation light in a preselected wavelength range; sensor means comprising a sensor body of porous high-temperature fluorescent inorganic oxide ceramic, for emitting an optical fluorescence signal responsive to oxygen content in the exhaust gas upon exposure of the sensor body to the excitation light at 400°
-650°
C.; and
fluorescence detector means for receiving a preselected wavelength range of the optical fluorescence signal which is above the excitation light wavelength range, and for generating an exhaust gas oxygen content output signal in response to the optical fluorescence signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. An internal combustion engine for a motor vehicle, comprising, in combination:
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a combustion chamber for burning an air/fuel mixture; an exhaust conduit for passing exhaust gases form the combustion chamber to atmosphere; an air/fuel mixture control means responsive to input signals for controlling the ratio of air and fuel in the air/fuel mixture; and an on-board gas composition sensor for monitoring oxygen content levels in the exhaust gases in the exhaust conduit for generating a sensor output signal as one of said input signals to the air/fuel mixture control means, the gas composition sensor comprising; sensor means comprising a sensor body of porous high-temperature fluorescent inorganic oxide ceramic exposed to the exhaust gases in the exhaust conduit, for emitting an optical fluorescence signal responsive to oxygen content level in the exhaust gases upon exposure of the sensor body to excitation light in a 350 to 525 nm wavelength range at 400°
-650°
C.light source means remote from the sensor body, for generating the excitation light, comprising a light emitter selected from a laser diode and a light emitting diode; an electrical resistance heater proximate the sensor body for heating the sensor body to a temperature between 400°
-650°
C.;fluorescence detector means remote from the sensor body, comprising a photospectrometer having an array detector for receiving the optical fluorescence signal from the sensor means and generating a response signal, and integration means for receiving and spectrally integrating the response signal over a range of 540 to 1000 nm over a preselected time interval of 0.5 to 4.0 seconds and generating an exhaust gas oxygen content output signal in response thereto; excitation detector means for detecting the excitation light and generating a compensation signal corresponding to the intensity of the excitation light for adjusting the exhaust gas oxygen content output signal in response thereto for generating said sensor output signal of the gas composition sensor; and light conveyor means comprising a fiber-optic cable for carrying both the excitation light from the light source means and the optical fluorescence signal from the sensor body, the fiber-optic cable comprising; a first portion extending between the light source means and a fiber-optic coupler; a second portion extending between the fiber-optic coupler and the sensor body, the sensor body being fused to the fiber-optic cable; a third portion extending between the fiber-optic coupler and the fluorescence detector means, having an optical filter for filtering out the excitation light carried by the fiber-optic cable; and a fourth portion extending between the fiber-optic coupler and the excitation detector. - View Dependent Claims (18, 19, 20)
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Specification