Air-fuel ratio detecting sensor

Abstract

An air-fuel ratio detecting combustion sensor. Combustion light signals of two given waveform bands are photoelectrically converted into corresponding electrical waveform signals. On the basis of phase difference in time points at which the two signals are generated, respectively, the air-fuel ratio is arithmetically determined.

I claim: 
     
       1. A sensor system for detecting air-fuel ratio in an internal combustion engine, comprising: (a) transparent combustion light extracting means for extracting combustion light produced in a combustion chamber of said engine;   (b) photoelectric conversion means for photoelectrically converting two given waveforms of the combustion light extracted through said combustion light extracting means into electrical wavelength signals; and   (c) air-fuel ratio determining means for determining the air-fuel ratio on the basis of said two wave-length signals supplied from said photoelectric conversion means, wherein said air-fuel ratio determining means includes peak detection means for detecting peaks of the two wave-length signals produced by said photoelectric conversion means, respectively, angular difference detecting means for detecting angular difference between the peaks detected by said peak detecting means, and air-fuel ratio determining means for determining the corresponding air-fuel ratio on the basis of said angular difference.   
     
     
       2. A sensor system according to claim 1, wherein said photoelectric conversion means include photoelectric conversion elements disposed, respectively, at bifurcated ends of an optical fiber cable leading to the interior of said combustion chamber and which elements are sensitive to light wavelength differing from each other. 
     
     
       3. A sensor system according to claim 1, wherein said photoelectric conversion means include combinations of interference filters for transmitting therethrough, respectively, the wavelengths differing from each other and photoelectric conversion elements, said combinations being disposed at bifurcated ends of an optical fiber cable leading to the interior of said combustion chamber. 
     
     
       4. A sensor system according to claim 1, wherein said air-fuel ratio determining means includes rise-up time point detecting means for detecting time points at which the two wavelength signals from said photoelectric conversion means rise up, respectively; said angular difference detecting means derives an angular difference in the rise-up time point between said two wavelength signals detected by said rise-up time point detecting means; and   said air-fuel ratio determining means determines a corresponding air-fuel ratio on the basis of said angular difference in the rise-up time point.   
     
     
       5. A sensor system according to claim 4, wherein two light wavelengths to undergo the photoelectric conversion are visible light rays having wavelengths located in the vicinity of infrared and ultraviolet regions, respectively. 
     
     
       6. A sensor system according to claim 1, wherein said corresponding air-fuel determining means includes a function memory storing data defining the air-fuel ratio and angular differences. 
     
     
       7. A sensor system according to claim 1, wherein said corresponding air-fuel determining means includes a function memory storing data defining the air-fuel ratio and angular differences. 
     
     
       8. A sensor system according to claim 1, wherein two light wavelengths to undergo the photoelectric conversion are visible light rays having wavelengths located in the vicinity of infrared and ultraviolet regions, respectively. 
     
     
       9. A sensor system for detecting air-fuel ratio in an internal combustion engine, comprising: (a) transparent combustion light extracting means for extracting combustion light produced in a combustion chamber of said engine;   (b) photoelectric conversion means for photoelectrically converting two given waveforms of the combustion light extracted through said combustion light extracting means into electrical wavelength signals; and   (c) air-fuel ratio determining means for determining the air-fuel ratio on the basis of said two wave-length signals supplied from said photoelectric conversion means, wherein said air-fuel ratio determining means includes peak detecting means for detecting peaks of the two wave-length signals produced by said photoelectric conversion means, respectively, angular difference detecting means for detecting an angular difference in the rise-up time point between said two wavelength signals detected by said rise-up time point detecting means; and   air-fuel ratio determining means for determining the corresponding air-fuel ratio on the basis of said angular difference.   
     
     
       10. A sensor system according to claim 9, wherein said corresponding air-fuel determining means includes a function memory storing data defining the air-fuel ratio and angular differences. 
     
     
       11. A sensor system according to claim 9, wherein said air-fuel ratio determining means includes peak detecting means for detecting peaks of the two wave-length signals produced by said photoelectric conversion means, respectively; said angular difference detecting means detects angular difference between the peaks detected by said peak detecting means, and   said air-fuel ratio determining means determines the corresponding air-fuel ratio on the basis of said angular difference.   
     
     
       12. A sensor system according to claim 11, wherein said corresponding air-fuel determining means includes a function memory storing data defining the air-fuel ratio and angular differences. 
     
     
       13. A sensor system according to claim 11, wherein two light wavelengths to undergo the photoelectric conversion are visible light rays having wavelengths located in the vicinity of infrared and ultraviolet regions, respectively. 
     
     
       14. A sensor system according to claim 9, wherein two light wavelengths to undergo the photoelectric conversion are visible light rays having wavelengths located in the vicinity of infrared and ultraviolet regions, respectively. .Iadd. 
     
     
       15.  In an internal combustion engine having a control system including a controller receiving inputs of sensed engine operating conditions and outputting control signals for controlling engine operating parameters to optimize the engine operating conditions, the improvement comprising: transparent combustion light extracting means for extracting combustion light produced in a combustion chamber of the engine;   photoelectric conversion means for photoelectrically converting two wavelengths of the combustion light extracted through said combustion light extracting means into electrical wavelength signals;   an air-fuel ratio determining means for determining the air-fuel ratio on the basis of said two wavelength signals supplied from said photoelectric conversion means, wherein said air-fuel ratio determining means includes means for detecting time points of the two wave-length signals, respectively, difference detecting means for detecting a time difference between the time points, and means for determining a corresponding air-fuel ratio on the basis of said time difference; and   said controller receiving said air-fuel ratio determined by said air-fuel ratio determining means as one of said inputs of sensed engine operating conditions. .Iaddend. .Iadd.16. In an internal combustion engine having a control system including a controller receiving inputs of sensed engine operating conditions and outputting control signals for controlling engine operating parameters to optimize the engine operating conditions, the improvement comprising:   first means for detecting light of the combustion within a cylinder of the engine and providing a first output signal that varies in accordance with intensity of the combustion light;   first means for comparing the first output signal with a first predetermined reference level;   means for producing a beginning point of combustion when the first output signal exceeds said first predetermined reference level;   second means for detecting light of the combustion within the combustion chamber of the engine and providing a second output signal wherein the wavelength of light detected by said second detecting means differs from the wavelength of light detected by said first detecting means and said second output signal varies in accordance with intensity of the combustion light detected by said second detecting means;   second means for comparing the second output signal with a second predetermined reference level;   means establishing a predetermined reference time point when said second output signal exceeds said second predetermined reference level;   third means for comparing a time point of said combustion beginning point with said reference time point to obtain a difference in time and providing a time difference output that changes in accordance with the operating conditions of the engine; and   said controller receiving said time difference output as one of said inputs of sensed operating conditions. .Iaddend. .Iadd.17. In an internal combustion engine having a control system including a controller receiving inputs of sensed engine operating conditions and outputting control signals for controlling engine operating parameters to optimize the engine operating conditions, the improvement comprising:   means for detecting light of combustion within a combustion chamber of the engine and providing an output signal that varies in accordance with intensity of the combustion light;   first means for comparing the output signal with a predetermined reference level;   means for producing a beginning point of combustion signal when the output signal exceeds said predetermined reference level;   second means for comparing a time of said combustion beginning point signal with a reference time point to obtain a difference in time and providing a time difference output that changes in accordance with the operating conditions of the engine; and   said controller receiving said time difference output as one of said inputs   
     
     
        of sensed operating conditions. .Iaddend. .Iadd.18.  In a control system for an internal combustion engine, the improvement comprising: means for detecting light of combustion in a combustion chamber of the engine and providing an output signal that varies in accordance with an intensity of the combustion light;   first means for comparing the output signal with a predetermined reference level;   means for determining and producing a beginning point of combustion signal when the output signal exceeds said predetermined reference level; and   second means for comparing a time of said combustion beginning point signal with a reference time point to obtain a difference in time and providing a time difference output that changes in accordance with operating   
     
     
        conditions of the engine. .Iaddend. .Iadd.19.  An engine control system according to claim 18, further comprising: said means for detecting combustion light having means for detecting a first wavelength of the combustion light;   said means for generating said reference time point having means for detecting a second wavelength of the combustion light and providing a second output signal that varies in accordance with an intensity of the second wavelength of the combustion light; means for comparing the second output signal with a second predetermined reference level whereby said reference time point is generated when the second output signal exceeds   
     
     
        said second predetermined reference level. .Iaddend. .Iadd.20.  A method, comprising the steps of: detecting light of combustion in a combustion chamber of an internal combustion engine and providing an output signal that varies in accordance with an intensity of the detected combustion light; comparing the output signal with a predetermined reference level;   determining a beginning point of the combustion when the output signal exceeds said predetermined reference level; and   comparing a time of said combustion beginning point with a reference time point to obtain a difference in time and providing a time difference output that changes in accordance with operating conditions of the engine.   
     
     
        .Iaddend. .Iadd.21.  A method according to claim 20, further comprising: said detecting of combustion light step including detecting a first wavelength of the combustion light;   generating said reference time point by detecting a second wavelength of the combustion light and providing a second output signal that varies in accordance with an intensity of the second wavelength of the combustion light; comparing the second output signal with a second predetermined reference level whereby said reference time point is generated when the second output signal exceeds said second predetermined reference level. .Iaddend. .Iadd.22. A method according to claim 20, further comprising: controlling an operating parameter of the engine in accordance with the   
     
     
        time difference output. .Iaddend. .Iadd.23.  A method of detecting combustion in a combustion chamber of an internal combustion engine, comprising: detecting light of the combustion within the combustion chamber and providing an output signal that varies according to an intensity of the combustion light as it increases from a beginning of combustion to a peak of the combustion light intensity;   determining and producing a beginning point of combustion signal from said output signal including comparing the output signal with a predetermined reference level and producing said beginning point of combustion signal when the output signal exceeds said predetermined reference level; and   comparing a time of said combustion beginning point signal with a reference time point to obtain a difference in time and providing a time difference output that changes in accordance with the operating conditions of the engine. .Iaddend.