USH427H - Air/fuel ratio detector - Google Patents

Air/fuel ratio detector Download PDF

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Publication number
USH427H
USH427H US06/682,220 US68222084A USH427H US H427 H USH427 H US H427H US 68222084 A US68222084 A US 68222084A US H427 H USH427 H US H427H
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United States
Prior art keywords
pump
metal oxide
air
solid electrolyte
fuel ratio
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US06/682,220
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English (en)
Inventor
Shintaro Hirate
Tetsusyo Yamada
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Niterra Co Ltd
Original Assignee
NGK Spark Plug Co Ltd
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Filing date
Publication date
Priority claimed from JP58238263A external-priority patent/JPS60129660A/ja
Priority claimed from JP58238262A external-priority patent/JPS60129659A/ja
Application filed by NGK Spark Plug Co Ltd filed Critical NGK Spark Plug Co Ltd
Application granted granted Critical
Publication of USH427H publication Critical patent/USH427H/en
Assigned to NGK SPARK PLUG CO., LTD. reassignment NGK SPARK PLUG CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: HIRATE, SHINTARO, YAMADA, TETSUSYO
Abandoned legal-status Critical Current

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/416—Systems
    • G01N27/417—Systems using cells, i.e. more than one cell and probes with solid electrolytes
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/403—Cells and electrode assemblies
    • G01N27/406—Cells and probes with solid electrolytes
    • G01N27/4065—Circuit arrangements specially adapted therefor

Definitions

  • the present invention relates to an air/fuel ratio detector for use in the measurement or control of the concentration of oxygen in exhaust gas from a combustion device such as an internal combustion engine or gas burner.
  • One type of oxygen sensor is capable of detecting combustion occurring at nearly a theoretically optimal or stoichiometric air/fuel ratio by sensing a change in electromotive force that is produced by the difference between the partial oxygen pressure of the exhaust gas and that of the atmospheric air.
  • This type of oxygen sensor comprises an ion-conductive solid electrolyte (e.g., stabilized zirconia) coated with porous electrode layers (e.g., porous layers of Pt).
  • This device is presently used in several applications, for example, in an automobile for the purpose of running its internal combustion engine at the theoretical air/fuel ratio.
  • the conventional oxygen sensor produces a great change in its output if the operating air/fuel ratio (A/F ratio, which is the weight ratio of air to fuel) is near the stoichiometric value of 14.7 but, otherwise, the resulting change in output is negligibly small. Therefore, the output from this sensor cannot be effectively used if the engine is operating at A/F ratios other than near the stoichiometric value.
  • A/F ratio which is the weight ratio of air to fuel
  • Japanese Patent Application (OPI) No. 153155/1983 shows an oxygen concentration detector comprising a pair of oxygen ion conductive and solid electrolyte plates each having an electrode layer on both sides in a selected area close to one end of the plates.
  • the two plates are fixed parallel to each other and spaced to leave a gap in an area corresponding to that selected area having the electrode layers.
  • One electrolyte plate with electrode layers is used as an oxygen pump element.
  • the other plate, also having electrode layers is used as an electrochemical cell element that operates by the difference in oxygen concentration between the ambient atmosphere and the gap between the two plates. This type of detector features quick response.
  • one object of the present invention is to provide an air/fuel ratio detector that is capable of accurately and responsively detecting the operating A/F ratio of a combustion burner such as an internal combustion engine whether it is operating in the fuel-rich region, fuel-lean region, at the stoichiometric A/F ratio point, or in the entire region or a part thereof.
  • Another object of the present invention is to provide an air/fuel ratio detector that enables a precise and simple feedback control over the above-mentioned A/F ratio regions.
  • An air/fuel ratio detector is summarized as comprising a solid electrolyte and electrochemical cell element sensitive to a difference in oxygen concentration and a solid electrolyte oxygen pump element, each element being in the form of an oxygen ion conductive solid electrolyte having porous electrodes formed on both sides. At least one of the elements has an electrically insulating substrate formed on one side except for the area where the porous electrode is provided. The insulating substrate is formed on either the electrochemical cell or the pump or possibly on both. The substrate has a metal oxide semiconductor layer formed on its surface. The electrochemical cell and the pump are disposed to face each other a small distance apart. The air/fuel ratio is detected both by a change in electrical properties of the metal oxide semiconductor layer and by an output signal provided by either the electromotive force of the electrochemical cell or by the pump current flowing through the pump.
  • An air-fuel ratio detector comprises a solid electrolyte, an electrochemical cell element sensitive to a difference in the concentration of oxygen, a solid electrolyte oxygen pump element and an oxygen reference element having a metal oxide semiconductor layer formed on the surface of an electrically insulating member.
  • the electrochemical cell and the pump are disposed to face each other a small distance apart.
  • the air/fuel ratio is detected both by a change in electrical properties in the metal oxide semiconductor layer and by an output signal provided by either the electromotive force of the electrochemical cell element or by the pump current flowing through the pump.
  • the detector of the present invention has the advantage of requiring only one sensor probe for achieving the detection of the accurate value of the A/F ratio over the entire operating range including both the fuel-rich and fuel-lean regions.
  • FIG. 1 is an illustration of the air/fuel ratio detector, both its probe and its circuitry according to one embodiment of the present invention
  • FIG. 2 is a cross section taken along the line I--I of FIG. 1;
  • FIG. 3 is a cross section taken along the line II--II of FIG. 2;
  • FIG. 4 is a cross section taken along the line III--III of FIG. 2;
  • FIG. 5 is an exploded perspective view of an electrochemical cell for detecting a difference in the concentration of oxygen
  • FIG. 6 is an exploded perspective view of an oxygen pump
  • FIG. 7 is a characteristic curve showing the profile of A/F ratio vs. the electrical resistance of a semiconducting metal oxide
  • FIG. 8 is a characteristic curve showing the profile of A/F ratio vs. pump-out current I p flowing through the pump, with the electromotive force of the electrochemical cell being held constant;
  • FIG. 9 is an illustration of the probe of the detector according to another embodiment.
  • FIG. 10 is an illustration of the detector according to still another embodiment of the present invention.
  • FIG. 11 is a cross section taken along the line I--I of FIG. 10;
  • FIG. 12 is a cross section taken along the line II--II of FIG. 11;
  • FIG. 13 is a cross section taken along the line III--III of FIG. 11;
  • FIG. 14 is a cross section taken along the line IV--IV of FIG. 11;
  • FIG. 15 is an exploded view of the oxygen pump and the electrochemical cell for sensing the difference in oxygen concentration
  • FIG. 16 is a characteristic curve showing the relation of the A/F ratio vs. pump-in current I p flowing through the pump, with the EMF of the electrochemical cell being held constant.
  • the A/F ratio detector according to one embodiment of the present invention will now be described with reference to FIGS. 1 to 6.
  • the detector has a probe section 2 which is mounted in, for example, an exhaust pipe 1 from an internal combustion engine.
  • the probe 2 includes a solid electrolyte oxygen pump element 3 and a solid electrolyte, electrochemical cell element 10 for sensing the difference in the concentration of oxygen.
  • the pump 3 consists of an ion conductive, solid electrolyte plate 6 about 0.5 mm thick and preferably made of stabilized zirconia. Porous platinum electrode layers 4 and 5 are formed on opposite sides of the plate 6 by a thick-film deposition technique to a thickness of about 20 ⁇ m.
  • the substrate 7 is in a tabular form having a thickness of about 0.25 mm and being made of a highly heat conductive and electrically insulating material such as alumina or spinel.
  • An electric heater 8 is formed around the window a on the heat-conductive and electrically insulating substrate 7 on its side opposite the side in contact with the solid electrolyte plate 6.
  • the heater 8 is spaced apart both from the periphery of the window a and from the outer edges of the substrate 7.
  • a tabular highly heatconductive and electrically insulating substrate 9 isolates the heater 8 from the outside by enclosing it against substrate 7.
  • the substrate 9 has a corresponding window b which, like the window a, complies with the contour of the Pt layer 5 so that the latter is exposed through the windows a and b.
  • the electrochemical cell 10 consists of an ion conductive, solid electrolyte plate 13 (about 0.5 mm thick and preferably made of stabilized zirconia) that has porous platinum electrode layers 11 and 12 formed to a thickness of about 20 ⁇ m on opposite sides of the electrolyte plate 13. These layers 11 and 12 are formed by a thick-film deposition technique.
  • the electrochemical cell 10 further includes a tabular highly heat-conductive but electrically insulating substrate 14 which is disposed on one side of the solid electrolyte plate 13. For instance, the substrate 14 may be located on the side where the porous Pt layer 11 is located.
  • the substrate 14 also has a window c complying with the contour of the Pt layer 11 so that the latter is exposed through the window.
  • An electric heater 15 is formed around the window c (see FIG. 5) on the side of the highly heat-conductive, electrically insulating substrate 14 opposite the side in contact with the solid electrolyte plate 13, with the heater 15 being spaced away both from the periphery of the window c and from the outer edges of the substrate 14.
  • a tabular, highly heat-conductive but electrically insulating substrate 16 isolates the heater 15 from the outside by covering it over the substrate 14.
  • the substrate 16 likewise has a window d which, like the window c, complies with the contour of the Pt layer 11 so that the latter is exposed through windows c and d.
  • the electrical elements of the electrodes 4 and 5 and the heater 8 located on the pump element 3 and of the electrodes 11 and 12, the heater 15, and the metal oxide 17 located on the electrochemical cell element 10 have respective external leads 18 which are formed by a thick-film deposition technique.
  • the pump element 3 and the electrochemical cell element 10 are erected side by side in the exhaust pipe 1 so that the Pt electrode layer 4 and the Pt layer 12 form a gap f which is as small as about 0.05 to 0.1 mm.
  • the two elements 3 and 10 are fixed together by filling the gap at the base portion with a heat-resistive and insulating spacer 19.
  • An adhesive filler may be used as the spacer.
  • a support 21 with a male thread 20 is fixed around the base portion of the combined pump 3 and electrochemical cell 10 by means of a heat-resistive and insulating adhesive member 22.
  • the probe 2 is securely mounted in the exhaust pipe 1 by engaging the male thread 20 to a corresponding female thread 23 in the exhaust pipe 1.
  • the fuel ratio detector probe 2 having the construction shown above may most advantageously be fabricated by the following procedure.
  • an ion conductive solid electrolyte plate 6 for example, a green sheet of solid electrolyte zirconia, is patterned on both sides with a predetermined pattern of porous platinum electrode layers 4 and 5 and associated leads 18. The pattern is printed by a thick-film deposition technique.
  • An electric heater made of a platinum resistor 8 and associated leads 18 is sandwiched between two highly heat-conductive and electrically insulating substrates 7 and 9, for example, two tabular green spinel sheets each having a window a or b.
  • the sheets 7 and 9 are pressed onto one side of the previously prepared green zirconia sheet 6, and the assembly is sintered to form an oxygen pump 3 of the ceramic clad type.
  • the electrochemical cell 10 is fabricated as shown in FIG. 5.
  • An ion conductive solid electrolyte plate 13 is patterned on both sides with a predetermined pattern of porous platinum electrode layers 11 and 12 and associated leads 18.
  • a highly heat-conductive and electrically insulating substrate 14 has an electric heater 15 and associated leads 18 formed on one side.
  • Another highly heat-conductive and electrically insulating substrate 16 is additionally patterned with predetermined pattern of leads 18 for the metal oxide semiconductor 17.
  • the thus obtained electrochemical cell is patterned with a predetermined pattern of metal oxide in the manner that the end portions of the leads 18 are bridged by said pattern and subsequently is baked in the sintering atmosphere to form a thick film of the metal oxide semiconductor 17 (e.g., titania).
  • the pump 3 and the electrochemical cell 10 are placed side by side with a thickness gauge inserted therebetween.
  • the pump 3 and the cell 10 are fixed together by filling the gap at the base portion with a spacer or heatresistive ceramic adhesive agent 19.
  • FIG. 1 An example of the electronic control unit 24 for use with the detector of the present invention is shown in FIG. 1.
  • the electromotive force e generated between the porous Pt electrode layers 11 and 12 on the electrochemical cell 10 is applied to the inverting input terminal of an operational amplifier A through a resistor R 1 .
  • the amplifier A produces an output proportional to the difference between the voltage e and a reference voltage V r applied to the noninverting input terminal of the amplifier A.
  • the output of the amplifier A drives a transistor Tr to control the pump current I p flowing between the Pt electrode layers 4 and 5 on the pump 3.
  • the pump current I p must be sufficiently large to maintain a constant electromotive force e at the level V r .
  • the control unit 24 also includes a resistor R o on the lead 18 to the Pt electrode layer 5 from a d.c. source B.
  • the output of the amplifier A and its inverting input are connected by a capacitor C.
  • the control unit 24 also has a set of output terminals 26 (FIG. 3) connected to the two leads 18 of different ends of the metal oxide layer 17 for picking up a signal indicative of a change in the electrical resistance of the metal oxide layer 17. Terminals 25 on either side of the resistor R o then provide a signal corresponding to the pump current I p to the Pt electrode 5.
  • the electric heater S for heating the porous Pt electrode layers 4 and 5 is connected to a power source 28, shown in FIG. 4.
  • the heater 15 for heating the semiconducting metal oxide layer 17 and porou Pt electrode layers 11 and 12 is connected to another power source 27, shown in FIG. 3.
  • FIG. 7 shows the functional dependence upon the A/F ratio for the electrical resistance of the semiconducting metal oxide layer 17 as measured at the output terminals 26.
  • the resistance is low in the fuel-rich region where the A/F ratio is smaller than the stoichiometric value of 14.7; at about 14.7, there occurs a sudden increase in the resistance, and in the fuel-lean region (A/F greater than 14.7), the resistance assumes a large value.
  • FIG. 8 shows the profile of A/F ratio vs. I p for a reference voltage V r , which is kept constant, say, at 20 mV.
  • the detector according to the embodiment shown in FIGS. 1 to 6 makes use of the characteristics depicted in FIGS. 7 and 8.
  • the output terminals 26 for detecting a change in the electrical resistance of the semiconducting metal oxide 17 are so designed that the detector will sense both the fuel-rich region (R ⁇ P) and the fuel-lean region (R>P), where P is a reference resistance set between the fuel-rich and fuel-lean asymptotic values.
  • the resistance of the semiconductor layer 17 is smaller than the reference resistance P and this binary information and an output signal corresponding to the resultant pump current I p flowing through the pump 3 may be combined so as to achieve a precise measurement or fine control of the A/F ratio for the fuel-rich region.
  • the resistance of the semiconductor layer 17 is greater than the reference resistance P.
  • This binary information and an output signal corresponding to the resultant pump current I p may be combined to obtain a precise measurement or control of the A/F ratio for the fuel-lean region. If the engine is to be operated near the stoichiometric A/F ratio of 14.7, the resistance of the semiconducting metal oxide 17 drops suddenly as the decreasing A/F ratio approaches the stoichiometric value of 14.7. This resistance change may be used directly or indirectly as a feedback control signal. The resistance value alone can be detected at the output terminal 26.
  • the detector of the present invention enables an accurate measurement of the A/F ratio of an engine over a wide range including both the fuel-rich and fuel-lean regions as well as the nearly stoichiometric region.
  • One application of this detector is a feedback control of the A/F ratio wherein the present level of A/F ratio is detected by the probe 2 mounted in the exhaust pipe 1 and is passed through a feedback loop to correct the A/F ratio so as to maintain the desired A/F ratio level.
  • the proportional change of I p with the A/F ratio in the fuel-lean region is already known and shown in, for example, Japanese Patent Application (OPI) No. 153155/1983.
  • the partial pressure of oxygen in the exhaust gas introduced into the gas f is modified by the action of the pump element 3 to a value which differs from the partial pressure of the oxygen in the exhaust gas flowing through the pipe 1.
  • the pump-out current I p supplied to the pump element 3 is controlled so that the electromotive force e of the electrochemical cell 10, as produced in response to the differential partial oxygen pressure, is maintained constant.
  • Sensitivity to CO gas would be the primary reason for this oxygen pump-out mechanism which occurs in the fuel-rich region.
  • FIG. 9 shows the detector probe 2 according to another embodiment of the present invention.
  • highly heat-conductive and electrically insulating substrates 7 and 9 enclosing the electric heater 8 and substrates 14 and 16 enclosing the electric heater 15 project from the top sides of the ion conductive, solid electrolyte plates 6 and 13.
  • the increased area of each substrate 7, 9, 14 and 16 permits easy mounting of the heaters 8 and 15, the semiconducting metal oxide layer 17 and associated leads 18 on the substrates.
  • a heater is buried in the highly heat-conductive and electrically insulating substrate that is formed on either surface of the oxygen pump element 3 or of the electrochemical cell element 10.
  • the substrate serves as a support for a semiconducting metal oxide layer.
  • the heater may be omitted if the gas to be analyzed is sufficiently hot to activate the pump 3, the electrochemical cell 10 and the semiconducting metal oxide layer 17 without the need of separate heating.
  • FIGS. 10 to 15 The A/F ratio detector according to a third embodiment of the present invention is shown in FIGS. 10 to 15.
  • the major difference between FIG. 10 and FIG. 1 concerns the position in which the semiconducting metal oxide layer 17 is mounted.
  • the components which are common to the embodiment of FIGS. 1 to 6 and that of FIGS. 10 to 15 are identified by like numerals.
  • the layout shown in FIG. 10 includes an oxygen reference element 117 as an additional component of the detector probe 2. As shown, this element consists of a highly heat-conductive and electrically insulating plate 16a (typically made of alumina and having a thickness of about 1 mm) which has an opening da that permits free passage of the exhaust gas.
  • a semiconducting metal oxide layer 17 (e.g., a titania element) is formed to a thickness of about 50 ⁇ m by a thick-film deposition technique on one side of the plate 16 above the opening da.
  • the reference element 117 may be mounted in the exhaust pipe 1 by fixing it to the electrochemical cell 10 with a heat resistive spacer 122 that is inserted between the reference element 117 and the cell 10 to provide a gap h.
  • the gap h need not be so small as the gap f.
  • the electrochemical cell 10 is bonded to the pump 3 by spacer 19.
  • a support 21 with a male thread 20 is fixed around the base portion of the combined structure of the pump 3, cell 10 and oxygen reference element 117 by means of a heat-resistive and insulating adhesive member 22.
  • the probe 2 is securely mounted in the exhaust pipe 1 by engaging the male thread 20 with a female thread 23 in the exhaust pipe 1.
  • the A/F ratio detector probe 2 having the structure shown in FIG. 10 may most advantageously be fabricated by a procedure which is similar to that used to fabricate the detector shown in FIG. 6. More specifically, the process is shown in FIG. 6 for the pump 3 (electrochem:ical cell 15, the components for the electrochemical cell 10 being referenced in parentheses).
  • An electric heater 8(15) made of a platinum resistor and associated leads 18 are sandwiched between two highly heat-conductive and electrically insulating substrates 7 and 9 (14 and 16).
  • two tabular green spinel sheets each having a window a or b (c or d) are pressed onto one side of the previously prepared green zirconia sheet 6(13).
  • the assembly is sintered to form an oxygen pump 3 (electrochemical cell 10) of the ceramic clad type.
  • a highly heat-conductive and electrically insulating plate 16a made of, for example, ceramic alumina with the opening da, is patterned on one side with a predetermined pattern of leads 18 for the semiconducting metal oxide layer 17.
  • the plate 16a is sintered to form a sintered substrate of an oxygen reference element 117.
  • a thick film of the semiconducting metal oxide e.g., titania
  • the pump 3, electrochemical cell 10 and the reference element 117 are placed side-by-side with a thickness gauge inserted between the pump 3 and the cell 10 to form the small gap f and another thickness gauge is inserted between the cell 10 and the reference element 117 to form the gap h.
  • the three elements are fixed together by filling the respective gaps at the base portion with spacers or heat-resistive ceramic adhesive agents 19 and 122.
  • FIG. 10 An example of the electronic control unit 24 for use with the detector according to the third embodiment of FIG. 10 is also shown in FIG. 10.
  • This control unit 24 is essentially the same as the control unit 24 in FIG. 1.
  • the control unit 24 has output terminals 26 similar to those of FIG. 3 for picking up a signal indicative of a change in the electrical resistance of the semiconducting metal oxide layer 17 in the oxygen reference element 117.
  • the electrical resistance of the semiconducting metal oxide 17 is used as a criterion for determining whether the engine is operating in the fuel-rich or fuel-lean region.
  • the electric heater 8 for heating the porous Pt electrode layers 4 and 5 is connected to a power source 28, shown in FIG. 14.
  • the heater 15 for heating the metal oxide layer 17 and the porous Pt electrode layers 11 and 12 is connected to another power source 27, as shown in FIG. 13.
  • the detector shown in FIGS. 10 to 15 has characteristics which are essentially the same as those illustrated in FIGS. 7 and 8.
  • the two heaters are integral with the pump 3 and the electrochemical cell 10, respectively.
  • a heater may be embedded in a tabular highly heat-conductive and electrically insulating substrate which does not necessarily have any opening and provides a support for the oxygen reference element. This tabular substrate is place in a side-by-side relation with the pump 3 and electrochemical cell 10.
  • the embedded heater will heat not only the metal oxide of the oxygen reference element but also an adjacent element (preferably the pump element). The heater may even be omitted if the gas to be analyzed is sufficiently hot to activate the pump 3, the cell element 10 and the oxygen reference element 117 without separate heating.
  • the pump current I p flowing through the pump element 3 has such a direction that oxygen is pumped out of the small gap f (I p >0). If desired, I p may be caused to flow in opposite direction (I p ⁇ 0) so that oxygen is pumped into the small gap f from the exhaust gas in the pipe 1.
  • FIG. 16 shows the dependence of the A/F ratio upon I p in this modified case, with the output of the electrochemical cell element 10 being held constant. The characteristics shown in FIG. 16 may also be used for the purposes of the present invention since they reflect a certain correlation between the operating A/F ratio and the pump current I p .
  • the electromotive force e generated by the electrochemical cell 10 also varies with the A/F ratio. This correlation may be used for achieving the purposes of the present invention.
  • the pump element and the sensor element are provided side by side in the exhaust pipe with a small gap therebetween. As preferable embodiments they are fixed together by filling the gap at the base portions with a spacer.
  • the gap formed between the pump element and the sensor element is preferable in order to sufficiently open the peripheral edges to the exhaust gases so as to increase its response.
  • the present invention is not limited to the configuration of open edges except for the base portions.
  • the gap between the pump element and the sensor element is preferably in a range from 0.01 to 0.15 mm. If the gap is too narrow, the responsivity is reduced.
  • an electrode layer for defining a small or fine gap is preferably a porous thick layer having a mean porosity of about 10-40% as determined by a porosimeter of pressurized mercury type in consideration of its diffusion resistance againt the associated component gases such as oxygen gas.
  • the electrode layer is formed by a suitable thin-film deposition technique
  • a porous layer such as a ceramic material to which may be added with a catalytic agent for obtaining a catalytic action.
  • a highly-responsive detection probe can be readily manufactured by the above described conditions.
  • the characteristics shown above that are provided by the detector probe 2 of the present invention may be used either individually or in combination for the purpose of effecting a continuous feedback control over the operating air/fuel ratio throughout the operating range by frequently changing the characteristics to be used.

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  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Health & Medical Sciences (AREA)
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  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
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  • Measuring Oxygen Concentration In Cells (AREA)
  • Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
US06/682,220 1983-12-17 1984-12-17 Air/fuel ratio detector Abandoned USH427H (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP58-238263 1983-12-17
JP58238263A JPS60129660A (ja) 1983-12-17 1983-12-17 空燃比検知装置
JP58238262A JPS60129659A (ja) 1983-12-17 1983-12-17 空燃比検知装置
JP58-238262 1983-12-17

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USH427H true USH427H (en) 1988-02-02

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Cited By (3)

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Publication number Priority date Publication date Assignee Title
US5102525A (en) * 1989-12-14 1992-04-07 Hitachi, Ltd. Planar oxygen sensor
US5460711A (en) * 1992-12-23 1995-10-24 Robert Bosch Gmbh Sensor for determining gas constituents and/or gas concentrations of gas mixtures
US5993625A (en) * 1996-03-19 1999-11-30 Ngk Spark Plug Co., Ltd. Exhaust gas sensor

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JPS61138155A (ja) * 1984-12-10 1986-06-25 Mitsubishi Electric Corp 空燃比検知装置
JP2005326396A (ja) * 2004-04-15 2005-11-24 Denso Corp ガスセンサ

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US4224113A (en) 1978-11-02 1980-09-23 Nissan Motor Company, Limited Method of detecting air/fuel ratio in combustor by detecting oxygen in combustion gas
US4225559A (en) 1979-01-22 1980-09-30 Ford Motor Company Ceramic element sensor
US4264425A (en) 1979-05-25 1981-04-28 Nissan Motor Company, Limited Device for detection of air/fuel ratio from oxygen partial pressure in exhaust gas
US4298573A (en) 1979-05-19 1981-11-03 Nissan Motor Company, Limited Device for detection of oxygen concentration in combustion gas
US4304652A (en) 1979-06-12 1981-12-08 Nissan Motor Company, Limited Device for detection of air/fuel ratio from oxygen partial pressure in exhaust gas
US4322383A (en) 1975-12-23 1982-03-30 Nippon Soken, Inc. Gas component detection apparatus
US4450065A (en) 1982-03-09 1984-05-22 Ngk Spark Plug Co., Ltd. Oxygen sensor
US4498968A (en) 1983-03-29 1985-02-12 Ngk Spark Plug Co., Ltd. Oxygen sensor
US4578172A (en) 1983-12-15 1986-03-25 Ngk Spark Plug Co. Air/fuel ratio detector

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US4272330A (en) * 1980-03-03 1981-06-09 Ford Motor Company Transient mode oxygen sensor and method
FR2494445A1 (fr) * 1980-11-17 1982-05-21 Socapex Capteur electrochimique des concentrations d'especes dans un melange fluide et systeme de regulation de la richesse d'un melange air-carburant mettant en oeuvre un tel capteur
JPS57131046A (en) * 1981-02-06 1982-08-13 Hitachi Ltd Air-fuel ratio controller for internal combustion engine
JPS5943348A (ja) * 1982-09-03 1984-03-10 Hitachi Ltd 空燃比センサ
JPS59208451A (ja) * 1983-05-11 1984-11-26 Mitsubishi Electric Corp 機関の空燃比センサ

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US3791936A (en) 1971-08-20 1974-02-12 Westinghouse Electric Corp Method and apparatus for monitoring the total combustibles and oxygen content of a gas
US4322383A (en) 1975-12-23 1982-03-30 Nippon Soken, Inc. Gas component detection apparatus
US4187486A (en) 1977-04-20 1980-02-05 Kabushiki Kaisha Toyota Chuo Kenkyusho Oxygen concentration detecting element and method of producing the same
US4224113A (en) 1978-11-02 1980-09-23 Nissan Motor Company, Limited Method of detecting air/fuel ratio in combustor by detecting oxygen in combustion gas
US4225559A (en) 1979-01-22 1980-09-30 Ford Motor Company Ceramic element sensor
US4298573A (en) 1979-05-19 1981-11-03 Nissan Motor Company, Limited Device for detection of oxygen concentration in combustion gas
US4264425A (en) 1979-05-25 1981-04-28 Nissan Motor Company, Limited Device for detection of air/fuel ratio from oxygen partial pressure in exhaust gas
US4304652A (en) 1979-06-12 1981-12-08 Nissan Motor Company, Limited Device for detection of air/fuel ratio from oxygen partial pressure in exhaust gas
US4450065A (en) 1982-03-09 1984-05-22 Ngk Spark Plug Co., Ltd. Oxygen sensor
US4498968A (en) 1983-03-29 1985-02-12 Ngk Spark Plug Co., Ltd. Oxygen sensor
US4578172A (en) 1983-12-15 1986-03-25 Ngk Spark Plug Co. Air/fuel ratio detector

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5102525A (en) * 1989-12-14 1992-04-07 Hitachi, Ltd. Planar oxygen sensor
US5460711A (en) * 1992-12-23 1995-10-24 Robert Bosch Gmbh Sensor for determining gas constituents and/or gas concentrations of gas mixtures
US5993625A (en) * 1996-03-19 1999-11-30 Ngk Spark Plug Co., Ltd. Exhaust gas sensor

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EP0147989A2 (fr) 1985-07-10
EP0147989A3 (fr) 1985-08-14

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