CN112505127B - Gas sensor control device, gas sensor device, and internal combustion engine control device - Google Patents
Gas sensor control device, gas sensor device, and internal combustion engine control device Download PDFInfo
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- CN112505127B CN112505127B CN202010948212.8A CN202010948212A CN112505127B CN 112505127 B CN112505127 B CN 112505127B CN 202010948212 A CN202010948212 A CN 202010948212A CN 112505127 B CN112505127 B CN 112505127B
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- 238000002485 combustion reaction Methods 0.000 title claims abstract description 39
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims abstract description 670
- 239000007789 gas Substances 0.000 claims abstract description 361
- 229910021529 ammonia Inorganic materials 0.000 claims abstract description 339
- 239000001301 oxygen Substances 0.000 claims abstract description 149
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 149
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 144
- 238000001514 detection method Methods 0.000 claims abstract description 133
- 238000000034 method Methods 0.000 claims abstract description 123
- 230000008569 process Effects 0.000 claims abstract description 122
- 238000012937 correction Methods 0.000 claims abstract description 83
- 238000005259 measurement Methods 0.000 claims abstract description 34
- 238000012545 processing Methods 0.000 claims abstract description 12
- 230000000694 effects Effects 0.000 claims description 4
- 238000005086 pumping Methods 0.000 description 84
- 239000007784 solid electrolyte Substances 0.000 description 23
- 239000010410 layer Substances 0.000 description 17
- 230000014509 gene expression Effects 0.000 description 15
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 15
- 238000012360 testing method Methods 0.000 description 13
- 101100333302 Arabidopsis thaliana EMF1 gene Proteins 0.000 description 12
- 101100508576 Gallus gallus CXCL8 gene Proteins 0.000 description 12
- 239000002184 metal Substances 0.000 description 12
- 229910052751 metal Inorganic materials 0.000 description 12
- 238000009792 diffusion process Methods 0.000 description 11
- 239000011241 protective layer Substances 0.000 description 11
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 10
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 7
- 239000000919 ceramic Substances 0.000 description 7
- 238000006243 chemical reaction Methods 0.000 description 7
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 6
- 239000003054 catalyst Substances 0.000 description 6
- 239000011148 porous material Substances 0.000 description 6
- 230000009467 reduction Effects 0.000 description 6
- 238000006722 reduction reaction Methods 0.000 description 6
- 238000010586 diagram Methods 0.000 description 5
- -1 oxygen ions Chemical class 0.000 description 5
- 101100333305 Arabidopsis thaliana EMF2 gene Proteins 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 229910052697 platinum Inorganic materials 0.000 description 4
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 3
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 3
- 239000004202 carbamide Substances 0.000 description 3
- 238000010531 catalytic reduction reaction Methods 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 238000003780 insertion Methods 0.000 description 3
- 230000037431 insertion Effects 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 230000000149 penetrating effect Effects 0.000 description 3
- 230000035945 sensitivity Effects 0.000 description 3
- 230000004913 activation Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 230000001012 protector Effects 0.000 description 2
- 229910020068 MgAl Inorganic materials 0.000 description 1
- 229910001570 bauxite Inorganic materials 0.000 description 1
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 description 1
- 238000003411 electrode reaction Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910052863 mullite Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000011895 specific detection Methods 0.000 description 1
- 229910052596 spinel Inorganic materials 0.000 description 1
- 239000011029 spinel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 239000000454 talc Substances 0.000 description 1
- 229910052623 talc Inorganic materials 0.000 description 1
- 231100000167 toxic agent Toxicity 0.000 description 1
- 239000003440 toxic substance Substances 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Classifications
-
- 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
- G01N27/419—Measuring voltages or currents with a combination of oxygen pumping cells and oxygen concentration cells
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
- F01N13/008—Mounting or arrangement of exhaust sensors in or on exhaust apparatus
-
- 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
- G01N27/4175—Calibrating or checking the analyser
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- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Health & Medical Sciences (AREA)
- Analytical Chemistry (AREA)
- Engineering & Computer Science (AREA)
- General Physics & Mathematics (AREA)
- Pathology (AREA)
- Electrochemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Immunology (AREA)
- Physics & Mathematics (AREA)
- Molecular Biology (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Testing Of Engines (AREA)
- Exhaust Gas After Treatment (AREA)
- Combined Controls Of Internal Combustion Engines (AREA)
- Measuring Oxygen Concentration In Cells (AREA)
Abstract
The invention provides a gas sensor control device, a gas sensor device and an internal combustion engine control device, which reduce the influence of the pressure of the measured gas and improve the measurement accuracy of the ammonia concentration. The gas sensor control device is provided with a control unit that performs the following processing: a first receiving process of receiving a first detection result corresponding to the concentration of ammonia, which is output from an ammonia detecting unit of a mixed potential system for detecting ammonia contained in a gas to be measured; a second receiving process of receiving a second detection result corresponding to the concentration of oxygen outputted from an oxygen detecting unit for detecting oxygen contained in the measured gas; a first concentration calculation process of calculating a first ammonia concentration contained in the measured gas based on the first detection result and the second detection result; and a pressure correction process for correcting the first ammonia concentration based on pressure information indicating the pressure of the measured gas obtained from an external device to obtain the second ammonia concentration of the measured gas so as to reduce the influence of the pressure of the measured gas on ammonia.
Description
Technical Field
The present invention relates to a gas sensor control device, a gas sensor device, and an internal combustion engine control device.
Background
An ammonia sensor that detects the concentration of ammonia contained in a gas to be measured (for example, exhaust gas from an internal combustion engine, etc.) is known (for example, patent document 1). The ammonia sensor has a mixed potential unit having a solid electrolyte and a pair of electrodes (a detection electrode, a reference electrode). The mixed potential means outputs an electromotive force corresponding to the ammonia concentration in the gas to be measured, but the electromotive force also reflects the oxygen concentration in the gas to be measured.
For example, as shown in patent document 2, a relational expression between the ammonia concentration, the oxygen concentration, and the electromotive force of the mixed potential means in the measured gas is known. By using such a relational expression, the ammonia concentration in the measured gas is calculated based on the electromotive force of the mixed potential means and the information of the oxygen concentration in the measured gas.
Prior art literature
Patent literature
Patent document 1: japanese patent application laid-open No. 2015-34814
Patent document 2: japanese patent laid-open publication No. 2018-72315
Disclosure of Invention
Problems to be solved by the invention
The pressure of the measured gas is not always constant but may vary. For example, when a throttle valve for adjusting the intake air amount of an internal combustion engine is fully opened, the pressure of exhaust gas (measured gas) from the internal combustion engine is higher than the pressure before the throttle valve is fully opened.
The inventors of the present invention found that: when the pressure of the measured gas changes in this way, the output (electromotive force) of the mixed potential means changes. In the conventional ammonia sensor, the influence of the pressure of the measured gas is not considered when the ammonia concentration is obtained.
The purpose of the present invention is to improve the accuracy of measuring the concentration of ammonia by reducing the influence of the pressure of a gas to be measured in a gas sensor control device, a gas sensor device, and an internal combustion engine control device.
Solution for solving the problem
The inventors found that: when the pressure of the measured gas changes, the output (electromotive force) of the mixed-potential ammonia detecting unit changes (that is, the output of the mixed-potential ammonia detecting unit is affected by the pressure of the measured gas). The reason for this is presumed to be as follows.
As shown in patent document 2, in the detection electrode of the mixed potential unit, the anode reaction of ammonia (2/3 NH 3) with oxygen ions (O 2-) to generate nitrogen (1/3N 2), water (H 2 O) and electrons (2 e -), and the cathode reaction of oxygen (1/2O 2) with electrons (2 e -) to generate oxygen ions (O 2-) occur simultaneously. The equilibrium point of the anode reaction with respect to the cathode reaction was observed as the electromotive force of the mixed potential cell. In such a case, for example, when the pressure of the measured gas becomes high, the electromotive force of the mixed potential means becomes small. It is considered that when the pressure of the measured gas increases, the apparent oxygen concentration is higher than that before the pressure of the measured gas increases, and as a result, it is estimated that the detection electrode of the mixed potential means easily reacts with oxygen, and the cathode reaction is relatively easily caused.
The method for solving the above problems is as follows. Namely:
<1> a gas sensor control device comprising a control unit that performs the following processing: a first receiving process of receiving a first detection result corresponding to a concentration of ammonia outputted from an ammonia detection unit of a mixed potential system for detecting ammonia contained in a gas to be measured; a second receiving process of receiving a second detection result corresponding to a concentration of oxygen outputted from an oxygen detecting unit for detecting oxygen contained in the gas to be measured; a first concentration calculation process of calculating a first ammonia concentration in the measured gas based on the first detection result and the second detection result; and a pressure correction process for correcting the first ammonia concentration based on pressure information indicating the pressure of the measured gas obtained from an external device to obtain a second ammonia concentration of the measured gas so as to reduce the influence of the pressure of the measured gas on the ammonia.
<2> In the gas sensor control device according to <1>, the pressure correction process is a process of obtaining the second ammonia concentration by correcting the first ammonia concentration using a correction coefficient based on the pressure information.
In the gas sensor control device according to <1> or <2>, the control unit may be configured to perform an oxygen pressure correction process for correcting the second ammonia concentration based on the pressure information of the measured gas to obtain a third ammonia concentration of the measured gas so as to reduce the influence of the pressure of the measured gas when the oxygen is influenced by the pressure of the measured gas.
<4> In the gas sensor control device according to any one of the above <1> to <3>, the control unit is configured to, when the oxygen is affected by the pressure of the measured gas, reduce the influence of the pressure of the measured gas on the ammonia and reduce the influence of the pressure of the measured gas on the oxygen, perform a simultaneous correction process in which a first ammonia concentration is corrected based on the pressure information of the measured gas, and obtain a fourth ammonia concentration of the measured gas, instead of the pressure correction process.
<5> A gas sensor device comprising: a mixed potential ammonia detection unit for detecting ammonia contained in the gas to be measured; an oxygen detection unit for detecting oxygen contained in the measurement gas; and the gas sensor control device according to any one of <1> to <4 >.
<6> An internal combustion engine control device for controlling an operation state of an internal combustion engine, the internal combustion engine control device comprising a control section that executes: a first receiving process of receiving a first detection result corresponding to a concentration of ammonia detected by an ammonia detection unit of a mixed potential type for detecting the presence of ammonia in a gas to be measured from the internal combustion engine; a second receiving process of receiving a second detection result corresponding to a concentration of oxygen outputted from an oxygen detecting unit for detecting oxygen contained in the gas to be measured; a first concentration calculation process of calculating a first ammonia concentration in the measured gas based on the first detection result and the second detection result; and a pressure correction process for correcting the first ammonia concentration based on pressure information indicating the pressure of the measured gas obtained from an external device to obtain a second ammonia concentration of the measured gas so as to reduce the influence of the pressure of the measured gas on the ammonia.
<7> In the control device for an internal combustion engine according to <6>, the pressure correction process is a process of obtaining the second ammonia concentration by correcting the first ammonia concentration using a correction coefficient based on the pressure information.
<8> In the control device for an internal combustion engine according to <6> or <7>, when the oxygen is affected by the pressure of the measured gas, the control unit performs an oxygen pressure correction process for correcting the second ammonia concentration based on the pressure information of the measured gas to obtain a third ammonia concentration of the measured gas so as to reduce the effect of the pressure.
<9> In the internal combustion engine control device according to any one of <6> to <8>, the control unit is configured to, when the oxygen is affected by the pressure of the measured gas, reduce the influence of the pressure of the measured gas on the ammonia and reduce the influence of the pressure of the measured gas on the oxygen, perform a simultaneous correction process in which a first ammonia concentration is corrected based on the pressure information of the measured gas, and obtain a fourth ammonia concentration of the measured gas, instead of the pressure correction process.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the present invention, in the gas sensor control device, the gas sensor device, and the internal combustion engine control device, the accuracy of measuring the ammonia concentration can be improved by reducing the influence of the pressure of the measured gas.
Drawings
Fig. 1 is a cross-sectional view of the multi-gas sensor according to embodiment 1 taken along the longitudinal direction.
Fig. 2 is an explanatory diagram showing a schematic configuration of the multi-gas sensor apparatus.
Fig. 3 is a cross-sectional view showing the structure of the ammonia sensor portion.
Fig. 4 is a flowchart showing the content of the ammonia concentration detection process.
Fig. 5 is an explanatory diagram showing an installation site of a pressure sensor for detecting the pressure of a measured gas.
Fig. 6 is a graph showing a relationship between the pressure of the measured gas and the ammonia concentration affected by the pressure of the measured gas.
Fig. 7 is a graph showing a relationship between the pressure of the measured gas and the oxygen concentration affected by the pressure of the measured gas.
Fig. 8 is a graph showing a relationship between the pressure of the measured gas and the ammonia concentration that reduces only the influence of the pressure of the measured gas on ammonia.
Fig. 9 is an explanatory diagram showing a schematic configuration of the internal combustion engine control system according to embodiment 2.
Fig. 10 is a flowchart showing the content of the ammonia concentration detection process in the ECU.
Fig. 11 is a flowchart showing the content of the ammonia concentration detection process according to embodiment 3.
Fig. 12 is a flowchart showing the content of the ammonia concentration detection process according to embodiment 4.
Fig. 13 is a flowchart showing the content of the ammonia concentration detection process according to embodiment 5.
Fig. 14 is a flowchart showing the content of the ammonia concentration detection process according to embodiment 6.
Description of the reference numerals
2: A first pumping unit (oxygen detecting portion); 42: an ammonia sensor unit (ammonia detection unit); 42x: a first ammonia sensor part; 42y: a second ammonia sensor part; 60: a microcomputer (SCU); 61: a CPU (control unit); 100A: a multi-gas sensor element section; 200A: a multi-gas sensor; 220: an ECU;221: ECU (internal combustion engine control device); 222: a CPU (control unit); 300: a gas sensor control device; 400: a multi-gas sensor device (gas sensor device); 500: a pressure sensor; 600: an internal combustion engine control system; l: an axis.
Detailed Description
< Embodiment 1>
Next, embodiment 1 of the present invention will be described with reference to fig. 1 to 5. In the present embodiment, a case is exemplified in which the gas sensor control device 300 provided in the multi-gas sensor device (an example of a gas sensor device) 400 performs a process of detecting the ammonia concentration in the exhaust gas (an example of a measured gas).
Fig. 1 is a cross-sectional view of the multi-gas sensor 200A according to embodiment 1 in the longitudinal direction (axis L direction), and fig. 2 is an explanatory view showing an outline configuration of the multi-gas sensor device 400 according to embodiment 1. For convenience of explanation, fig. 2 shows only a cross section of the multi-gas sensor element portion 100A housed in the multi-gas sensor 200A along the longitudinal direction (axis L direction).
The multi-gas sensor apparatus 400 is used in a urea SCR (selective catalytic reduction) system for purifying nitrogen oxides (NO x) contained in exhaust gas (an example of a measured gas) discharged from a diesel engine (an example of an internal combustion engine) of an automobile. Urea SCR systems are systems that chemically react ammonia (NH 3) with nitrogen oxides (NO x) to reduce the nitrogen oxides to nitrogen (N 2) and purify the nitrogen oxides contained in exhaust gas. In the urea SCR system, when the amount of ammonia supplied to nitrogen oxides is excessive, there is a possibility that unreacted ammonia is contained in the exhaust gas and is directly discharged to the outside. The multi-gas sensor device 400 measures the concentration of ammonia contained in the exhaust gas (measured gas) in order to monitor the emission of such ammonia. As described later, the multi-gas sensor device 400 is configured to measure the concentration of NO x in addition to the concentration of ammonia.
The multi-gas sensor apparatus 400 includes a multi-gas sensor 200A and a gas sensor control apparatus (controller) 300.
As shown in fig. 1, the multi-gas sensor 200A is a module including a multi-gas sensor element unit 100A for detecting the ammonia concentration and the NO x concentration.
The multi-gas sensor 200A includes: a plate-like multi-gas sensor element portion 100A extending in the direction of the axis L; a tubular main metal fitting member 138 having a threaded portion 139 formed on an outer surface thereof for fixing to an exhaust pipe; a cylindrical ceramic sleeve 106 configured to surround a radial periphery of the multi-gas sensor element portion 100A; an insulating contact member 166 disposed in a state in which an inner wall surface of a contact insertion hole 168 penetrating in the direction of the axis L surrounds the periphery of the rear end portion of the multi-gas sensor element portion 100A; and a plurality of (only 2 are shown in fig. 1) connection terminals 110 arranged between the multi-gas sensor element portion 100A and the insulating contact member 166.
The main metal fitting member 138 has a through hole 154 penetrating in the direction of the axis L, and has a substantially cylindrical shape having a shelf portion 152 protruding inward in the radial direction of the through hole 154. The main metal fitting member 138 holds the multi-gas sensor element portion 100A in a state in which the distal end side of the multi-gas sensor element portion 100A is disposed outside the distal end side of the through hole 154, and the electrode terminal portions 80A, 82A are disposed outside the rear end side of the through hole 154. The shelf 152 is formed as an inward tapered surface having an inclination with respect to a plane perpendicular to the direction of the axis L.
Inside the through hole 154 of the main metal fitting member 138, the annular ceramic holder 151, the powder filling layers 153 and 156 (hereinafter also referred to as "the" talc rings 153 and 156 ") and the ceramic sleeve 106 are stacked in this order from the tip end side to the rear end side in a state of surrounding the radial periphery of the multi-gas sensor element portion 100A. A pinch seal 157 is disposed between the ceramic sleeve 106 and the rear end 140 of the main metal fitting member 138, and a metal holder 158 for holding the slide ring 153 and the ceramic holder 151 so as to maintain air tightness is disposed between the ceramic holder 151 and the frame 152 of the main metal fitting member 138. Further, the rear end 140 of the main metal fitting member 138 is pressed so that the ceramic sleeve 106 is pressed toward the tip end side via the pressing seal 157.
On the other hand, a double-layered outer protector 142 and an inner protector 143 made of metal (for example, stainless steel or the like) that covers the protruding portion of the multi-gas sensor element portion 100A and has a plurality of hole portions are attached to the outer periphery of the tip end side (lower side in fig. 1) of the main metal fitting member 138 by welding or the like.
An outer tube 144 is fixed to the rear end side outer periphery of the main metal fitting member 138. A gasket 150 is disposed in an opening portion on the rear end side (upper side in fig. 1) of the outer tube 144, and the gasket 150 is formed with lead insertion holes 161 through which a plurality of leads 146 (only 3 are shown in fig. 1) are inserted, and the plurality of leads 146 are electrically connected to the electrode terminal portions 80A, 82A of the multi-gas sensor element portion 100A, respectively. For simplicity, the electrode terminal portions on the front and rear surfaces of the multi-gas sensor element portion 100A are denoted by reference numerals 80A and 82A, respectively, in fig. 1, but in reality, a plurality of electrode terminal portions are formed in accordance with the number of electrodes and the like included in the NO x sensor portion 30A, the first ammonia sensor portion, and the second ammonia sensor portions 42x and 42y, which will be described later.
Further, an insulating contact member 166 is disposed on the rear end side (upper side in fig. 1) of the multi-gas sensor element portion 100A protruding from the rear end portion 140 of the main metal fitting member 138. The insulating contact member 166 is disposed around the electrode terminal portions 80A and 82A formed on the front and rear surfaces of the rear end side of the multi-gas sensor element portion 100A. The insulating contact member 166 is formed in a cylindrical shape having a contact insertion hole 168 penetrating in the direction of the axis L, and has a flange portion 167 protruding radially outward from the outer surface. The insulating contact member 166 is disposed inside the outer tube 144 by abutting the flange portion 167 against the outer tube 144 via the holding member 169. The connection terminal 110 on the insulating contact member 166 side is electrically connected to the electrode terminal portions 80A and 82A of the multi-gas sensor element portion 100A, and is electrically connected to the outside through the lead wire 146.
As shown in fig. 2, the gas sensor control device 300 is electrically connected to an ECU (engine controller unit) 220. The end of the lead wire 146 extending from the multi-gas sensor 200A is connected to a connector configured to be electrically connected to a connector on the gas sensor control device 300 side.
Next, the structure of the multi-gas sensor element unit 100A included in the multi-gas sensor 200A will be described. The multi-gas sensor element unit 100A includes an NO x sensor unit 30A and an ammonia sensor unit 42 having the same structure as a known NO x sensor.
The NO x sensor unit 30A mainly includes a NO x detection unit including the first pumping unit 2, the oxygen concentration detection unit 6, and the second pumping unit 4. The NO x sensor unit 30A has a structure in which an insulating layer 23e, a first solid electrolyte body 2a, an insulating layer 23d, a third solid electrolyte body 6a, an insulating layer 23c, a second solid electrolyte body 4a, and insulating layers 23b and 23a are laminated in this order. As shown in fig. 2, a first measurement chamber S1 is formed between the first solid electrolyte body 2a and the third solid electrolyte body 6 a. The exhaust gas is introduced from the outside through a first diffusion resistor 8a disposed at the left end (inlet) of the first measurement chamber S1. A protective layer 9 made of porous material is disposed outside the first diffusion resistor 8 a.
A second diffusion resistor 8b is disposed at an end of the first measurement chamber S1 opposite to the inlet. In fig. 2, a second measurement chamber S2 is formed on the right side of the first measurement chamber S1, and communicates with the first measurement chamber S1 through a second diffusion resistor 8b. The second measurement chamber S2 penetrates the third solid electrolyte body 6a and is formed between the first solid electrolyte body 2a and the second solid electrolyte body 4 a.
An elongated heat generating resistor 21 extending in the longitudinal direction of the multi-gas sensor element portion 100A is buried between the insulating layers 23b, 23 a. The heat generating resistor 21 is provided with a heat generating portion on a tip side in an axial direction (long side direction), and a pair of lead portions are provided from the heat generating portion toward a rear end side in the axial direction. The heat generating resistor 21 and the insulating layers 23b, 23a correspond to heaters. The heater is used for raising the temperature of the gas sensor to an active temperature to improve the oxygen ion conductivity of the solid electrolyte body and stabilize the operation.
The insulating layers 23a to 23e are mainly made of alumina, and the first diffusion resistor 8a and the second diffusion resistor 8b are made of porous material such as alumina. The heating resistor 21 is made of platinum or the like. The heat generating portion of the heat generating resistor 21 may be formed in a meandering pattern, for example.
The first pumping unit 2 pumps out or draws in oxygen in the exhaust gas (measured gas) introduced into the first measuring chamber S1. The first pumping unit 2 includes a first solid electrolyte body 2a mainly composed of zirconia having oxygen ion conductivity, an inner first pumping electrode 2b disposed so as to sandwich the first solid electrolyte body 2a, and an outer first pumping electrode 2c serving as a counter electrode. The inner first pumping electrode 2b faces the first measuring chamber S1. The inner first pumping electrode 2b and the outer first pumping electrode 2c are each mainly made of platinum, and the surface of the inner first pumping electrode 2b is covered with a protective layer 11 made of a porous material.
The insulating layer 23e corresponding to the upper surface of the outer first pumping electrode 2c is hollowed out, and the hollowed-out portion is filled with the porous body 13. The outside first pumping electrode 2c is connected to the outside through the porous body 13, and thus gas (oxygen) can be introduced and discharged.
Further, the oxygen concentration in the exhaust gas (measured gas) can be grasped based on the first pumping current Ip1 flowing through the first pumping means (an example of the oxygen detecting portion) 2. As will be described later, the oxygen concentration in the exhaust gas obtained based on the first pumping current Ip1 is used for detecting the ammonia concentration in the exhaust gas.
The oxygen concentration detection means 6 includes a third solid electrolyte body 6a mainly composed of zirconia, and a detection electrode 6b and a reference electrode 6c arranged so as to sandwich the third solid electrolyte body 6 a. The detection electrode 6b faces the first measurement chamber S1 at a position downstream of the inner first pumping electrode 2 b. The detection electrode 6b and the reference electrode 6c are each mainly made of platinum.
The insulating layer 23c is cut so that the reference electrode 6c connected to the third solid electrolyte body 6a is disposed therein, and the cut portion (cut portion) is filled with a porous body to form the reference oxygen chamber 15. Then, by passing a weak constant current through the oxygen concentration detection means 6 in advance using the Icp supply circuit 54, oxygen is fed from the first measurement chamber S1 into the reference oxygen chamber 15, and this serves as an oxygen reference.
The second pumping means 4 includes a second solid electrolyte body 4a mainly composed of zirconia, an inner second pumping electrode 4b disposed on a surface of the second solid electrolyte body 4a facing the second measurement chamber S2, and a second pumping counter electrode 4c serving as a counter electrode. The inner second pumping electrode 4b and the second pumping counter electrode 4c are each mainly made of platinum. The second pumping counter electrode 4c is disposed on the second solid electrolyte body 4a at a position of the cut portion of the insulating layer 23c, facing the reference electrode 6c and the reference oxygen chamber 15.
As shown in fig. 2, the inner first pumping electrode 2b, the detection electrode 6b, and the inner second pumping electrode 4b are connected to a reference potential, respectively. In addition, the NO x sensor portion 30A constitutes an NO x detection portion except for the heating resistor 21 and the insulating layers 23b, 23a (for example, the first pumping unit 2, the oxygen concentration detection unit 6, the second pumping unit 4, and the like).
Next, the ammonia sensor portion 42 will be described. The ammonia sensor unit 42 includes two ammonia sensor units (a first ammonia sensor unit 42x and a second ammonia sensor unit 42 y) of a mixed potential system. Fig. 3 is a cross-sectional view showing the structure of the ammonia sensor portion 42. As shown in fig. 3, the multi-gas sensor element portion 100A has a first ammonia sensor portion 42x and a second ammonia sensor portion 42y separated from each other in the width direction as ammonia sensor portions. The first ammonia sensor portion 42x and the second ammonia sensor portion 42y each include a mixed potential unit.
The first ammonia sensor portion 42x and the second ammonia sensor portion 42y are formed on the insulating layer 23a constituting the outer surface (lower surface) of the NO x sensor portion 30A. The first ammonia sensor portion 42x has a first reference electrode 42ax formed on the insulating layer 23a, and a first solid electrolyte body 42dx is formed so as to cover the lower surface and the side surfaces of the first reference electrode 42 ax. A first detection electrode 42bx is formed on the surface of the first solid electrolyte body 42dx. The ammonia concentration in the measurement gas is detected by such a change in electromotive force between the first reference electrode 42ax and the first detection electrode 42bx. Similarly, the second ammonia sensor portion 42y has a second reference electrode 42ay formed on the insulating layer 23a, and a second solid electrolyte body 42dy formed so as to cover the lower surface and the side surfaces of the second reference electrode 42 ay. A second detection electrode 42by is formed on the surface of the second solid electrolyte body 42dy. The ammonia concentration in the measurement gas is detected by such a change in electromotive force between the second reference electrode 42ay and the second detection electrode 42by.
In the present embodiment, the NO x detection portion and the ammonia sensor portion 42 (the first ammonia sensor portion 42x and the second ammonia sensor portion 42 y) are arranged so as to sandwich the heater (the heating resistor 21, the insulating layer 23b, and the insulating layer 23 a) in the stacking direction, and therefore the NO x detection portion and the two ammonia sensor portions 42x and 42y are adjacent to the heater (are substantially the same distance from the heater). As a result, the temperatures of the two ammonia sensor portions 42x, 42y can be controlled more accurately.
The first ammonia sensor portion 42x and the second ammonia sensor portion 42y are integrally covered with a protective layer 23g made of porous material. The protective layer 23g is used to prevent the toxic substance from adhering to the first detection electrode 42bx and the second detection electrode 42by and to adjust the diffusion rate of the gas to be measured flowing into the first ammonia sensor part 42x and the second ammonia sensor part 42y from the outside. As a material forming the protective layer 23g, at least one material selected from the group consisting of alumina (aluminum oxide), spinel (MgAl 2O4), bauxite, and mullite can be exemplified. The diffusion rate of the gas to be measured is adjusted by the protective layer 23g by appropriately setting the conditions such as the thickness, particle diameter, particle size distribution, porosity, and blending ratio of the protective layer 23 g.
In other embodiments, the first ammonia sensor portion 42x, the second ammonia sensor portion 42y, and the like may be exposed without providing the protective layer 23g, and the protective layer may be provided separately for each of the first ammonia sensor portion 42x and the second ammonia sensor portion 42 y.
The first detection electrode 42bx and the second detection electrode 42by can be formed of a material containing Au as a main component (for example, 70 mass% or more). The first reference electrode 42ax and the second reference electrode 42ay may be formed of Pt alone or a material containing Pt as a main component (for example, 70 mass% or more). The first detection electrode 42bx and the second detection electrode 42by are electrodes where ammonia gas is difficult to burn on the electrode surfaces. The ammonia passes through the detection electrode 42bx (42 by) and then reacts with oxygen ions (electrode reaction) at the interface between the detection electrode 42bx (42 by) and the reference electrode 42ax (42 ay), thereby detecting the concentration of ammonia. The specific detection process of the ammonia concentration will be described later.
In the present embodiment, the impedance of the oxygen concentration detection means 6 is measured, and the heater (the heat generating resistor 21) is heated based on the impedance. Therefore, in the vicinity of the oxygen concentration detection cell 6, the temperature of the multi-gas sensor element portion 100A is maintained at the most stable value (the value at which the temperature can be estimated). Therefore, the first ammonia sensor portion 42x and the second ammonia sensor portion 42y are disposed in the vicinity of the oxygen concentration detection cell 6, so that the temperatures of the two ammonia sensor portions 42x and 42y are kept at stable values.
Next, an example of the structure of the gas sensor control device 300 will be described with reference to fig. 2. The gas sensor control device 300 includes a (analog) control circuit 59 and a microcomputer (sensor control unit, SCU) 60 on a circuit board. The microcomputer 60 controls the entire gas sensor control device 300, and includes a CPU (central processing unit) 61, a RAM 62, a ROM 63, a signal input/output unit 64, an a/D converter 65, and a block (not shown) and the like. In the microcomputer 60, a program stored in advance in the ROM 63 or the like is executed by the CPU 61.
The control circuit 59 includes a reference voltage comparing circuit 51, an Ip1 driver circuit 52, a Vs detection circuit 53, an Icp supply circuit 54, an Ip2 detection circuit 55, a Vp2 application circuit 56, a heater driving circuit 57, a first electromotive force detection circuit 58a, and a second electromotive force detection circuit 58b.
The control circuit 59 controls the NO x sensor unit 30A, detects the first pumping current Ip1 and the second pumping current Ip2 flowing through the NO x sensor unit 30A, and outputs the detected first pumping current Ip1 and second pumping current Ip2 to the microcomputer 60.
The first and second electromotive force detection circuits 58a and 58b detect the ammonia concentration output (electromotive force) between the electrodes of the first and second ammonia sensor parts 42x and 42y, and output the detected ammonia concentration output (electromotive force) to the microcomputer 60.
The outer first pumping electrode 2c of the NO x sensor section 30A is connected to the Ip1 driver circuit 52, and the reference electrode 6c is connected in parallel with the Vs detection circuit 53 and the Icp supply circuit 54. The second pumping counter electrode 4c is connected in parallel to the Ip2 detection circuit 55 and the Vp2 application circuit 56. The heater driving circuit 57 is connected to a heater (specifically, the heat generating resistor 21).
The pair of electrodes 42ax and 42bx of the first ammonia sensor portion 42x are connected to the first electromotive force detection circuit 58a, respectively. Similarly, the pair of electrodes 42ay, 42by of the second ammonia sensor portion 42y are connected to the second electromotive force detection circuit 58b, respectively.
Each of the circuits 51 to 57 has the following functions. The Ip1 driver circuit 52 supplies the first pumping current Ip1 between the inner side first pumping electrode 2b and the outer side first pumping electrode 2c, and detects the first pumping current Ip1 at this time. The Vs detection circuit 53 detects the voltage Vs between the detection electrode 6b and the reference electrode 6c, and outputs the detection result to the reference voltage comparison circuit 51.
The reference voltage comparing circuit 51 compares a reference voltage (for example, 425 mV) with the output of the Vs detecting circuit 53 (voltage Vs), and outputs the comparison result to the Ip1 driver circuit 52. The Ip1 driver circuit 52 controls the flow direction and magnitude of the Ip1 current so that the voltage Vs becomes equal to the reference voltage, and adjusts the oxygen concentration in the first measurement chamber S1 to a predetermined value that is a level at which NO x is not decomposed.
The Icp supply circuit 54 supplies a weak current Icp to the space between the detection electrode 6b and the reference electrode 6c, and supplies oxygen from the first measurement chamber S1 into the reference oxygen chamber 15 to expose the reference electrode 6c to a predetermined oxygen concentration as a reference.
The Vp2 application circuit 56 applies a constant voltage Vp2 (for example, 450 mV) to the extent that NO x gas in the measured gas is decomposed into oxygen and N 2 gas between the inner second pumping electrode 4b and the second pumping counter electrode 4c to decompose NO x into nitrogen and oxygen.
The Ip2 detection circuit 55 detects the second pumping current Ip2 flowing through the second pumping means 4 when oxygen generated by the decomposition of NO x is pumped out from the second measurement chamber S2 to the second pumping counter electrode 4c side via the second solid electrolyte body 4 a.
The Ip1 driver circuit 52 outputs the detected value of the first pumping current Ip1 to the a/D converter 65. In addition, the Ip2 detection circuit 55 outputs the detected value of the second pumping current Ip2 to the a/D converter 65. The a/D converter 65 digitally converts these values and outputs them to the CPU61 via the signal input/output section 64.
Next, an example of control performed by the control circuit 59 included in the gas sensor control device 300 will be described. First, when the engine is started and supplied with electric power from an external power source, the heater is operated via the heater driving circuit 57, and the first pumping unit 2, the oxygen concentration detecting unit 6, and the second pumping unit 4 are heated to the activation temperature. The Icp supply circuit 54 supplies a weak current Icp between the detection electrode 6b and the reference electrode 6c, and oxygen is supplied from the first measurement chamber S1 into the reference oxygen chamber 15 as an oxygen reference. In addition, when the NO x sensor portion 30A is heated to an appropriate temperature by the heater, the first ammonia sensor portion 42x and the second ammonia sensor portion 42y on the NO x sensor portion 30A also rise in temperature to a desired temperature as well.
When each unit is heated to the activation temperature, the first pumping unit 2 pumps oxygen in the exhaust gas flowing into the first measurement chamber S1 from the inner first pumping electrode 2b toward the outer first pumping electrode 2 c. At this time, the oxygen concentration in the first measurement chamber S1 is a concentration corresponding to the inter-electrode voltage (inter-terminal voltage) Vs of the oxygen concentration detection means 6, and therefore the Ip1 driver circuit 52 controls the first pumping current Ip1 flowing to the first pumping means 2 so that the inter-electrode voltage Vs becomes the reference voltage (for example, 425 mV), and adjusts the oxygen concentration in the first measurement chamber S1 to a level at which NO x is not decomposed. The oxygen concentration in the exhaust gas flowing into the first measurement chamber S1 is obtained based on the first pumping current Ip1 detected by the Ip1 driver circuit 52, and is used for detecting the ammonia concentration, which will be described later.
The measured gas whose oxygen concentration has been adjusted further flows toward the second measurement chamber S2. Further, the Vp2 application circuit 56 applies a constant voltage Vp2 (a voltage higher than the value of the control voltage of the oxygen concentration detection means 6, for example, 450 mV) to the extent that the NO x gas in the measured gas is decomposed into oxygen and N 2 gas as an inter-electrode voltage (inter-terminal voltage) of the second pumping means 4 to decompose NO x into nitrogen and oxygen. Then, a second pumping current Ip2 is flowed to the second pumping unit 4 so that oxygen generated by the decomposition of NO x is pumped out from the second measurement chamber S2. At this time, by detecting the second pumping current Ip2, the concentration of NO x in the measured gas can be detected.
By detecting the ammonia concentration output (electromotive force) between the pair of electrodes 42ax, 42bx by the first electromotive force detection circuit 58a, the ammonia concentration in the measurement gas can be detected as described below. Further, the ammonia concentration output (electromotive force) between the pair of electrodes 42ay, 42by is detected by the second electromotive force detection circuit 58b, whereby the ammonia concentration in the measurement gas can be detected.
Next, the calculation process for each gas concentration (particularly, ammonia concentration) performed by the microcomputer (SCU) 60 of the gas sensor control device 300 will be described.
Further, since the ammonia sensor unit 42 detects not only ammonia but also NO 2, when NO 2 gas other than ammonia is contained in the gas to be measured, the accuracy of detecting ammonia may be lowered. Therefore, each concentration of ammonia gas and NO 2 is calculated by using two ammonia sensor portions 42 having different ratios of sensitivity to ammonia and sensitivity to NO x as the ammonia sensor portions 42.
For example, the sensor output of the ammonia sensor portion 42 is for x: ammonia concentration, y: NO 2 gas concentration, D: o 2 concentration, expressed as F (x, y, D). When two ammonia sensor units having different sensitivity ratios are used, two equations F 1(mx、ny、D)、F2 (sx, ty, D) (m, n, s, t is a coefficient) are obtained. F1, F2, D are obtained from the sensor output, and thus two unknowns (x, y) may be solved from the two equations.
In the present specification, the detection of ammonia and the calculation of the ammonia concentration by the ammonia sensor unit 42 will be described in detail. Further, details of the detection of NO 2 by the ammonia sensor unit 42 and the calculation processing of the concentration of NO 2 are omitted.
An electromotive force is generated between the first reference electrode 42ax and the first detection electrode 42bx of the first ammonia sensor unit (an example of an ammonia detection unit) 42x according to the concentration of ammonia contained in the exhaust gas (the measured gas). The first electromotive force detection circuit 58a detects an electromotive force between the first reference electrode 42ax and the first detection electrode 42bx as a first ammonia electromotive force EMF1.
Similarly, an electromotive force is generated between the second reference electrode 42ay and the second detection electrode 42by of the second ammonia sensor unit (an example of an ammonia detection unit) 42y in accordance with the concentration of ammonia in the gas to be measured. Further, the second electromotive force detection circuit 58b detects the electromotive force between the second reference electrode 42ay and the second detection electrode 42by as the second ammonia electromotive force EMF2.
The ROM 63 of the microcomputer 60 stores various data (relational expressions and the like) shown below, for example. The CPU61 reads various data from the ROM 63, and performs various arithmetic processing based on the value of the first pumping current Ip1, the value of the second pumping current Ip2, the first ammonia electromotive force EMF1, and the second ammonia electromotive force EMF 2.
The ROM 63 stores a "first ammonia electromotive force & O 2 concentration output-ammonia concentration output relation", a "second ammonia electromotive force & O 2 concentration output-ammonia concentration output relation", a "first pumping current Ip1-O 2 concentration output relation", a "second pumping current Ip2-NO x concentration output relation", and the like.
The expression "first ammonia electromotive force & O 2 concentration output-ammonia concentration output relation" is an expression showing a relation between the first ammonia electromotive force EMF1 output from the first ammonia sensor unit 42x, the O 2 concentration output derived from the "first pumping current Ip1-O 2 concentration output relation" described later, and the ammonia concentration output (first ammonia concentration) related to the ammonia concentration of the measured gas, which does not reduce (does not take into consideration) the influence of the pressure of the measured gas.
The "second ammonia electromotive force & O 2 concentration output-ammonia concentration output relation" is a relation between the second ammonia electromotive force EMF2 output from the second ammonia sensor unit 42y, the O 2 concentration output derived from the "first pumping current Ip1-O 2 concentration output relation" described later, and the ammonia concentration output (first ammonia concentration) related to the ammonia concentration of the measured gas, which does not reduce (does not take into consideration) the influence of the pressure of the measured gas.
The "first pumping current Ip1-O 2 concentration output relation" is a relation between the first pumping current Ip1 and the O 2 concentration of the measured gas.
The "second pumping current Ip2-NO x concentration output relation" is a relation between the second pumping current Ip2 and the NO x concentration of the measured gas.
The various data may be set to a predetermined relational expression as described above, and may be set to a table, for example, as long as the data is obtained by calculating the concentration of the various gases from the output of the sensor. In addition, the value (relational expression, table, and the like) obtained by using a gas model having a known gas concentration may be used.
Next, an ammonia concentration detection process for detecting an ammonia concentration (an example of a second ammonia concentration) performed by the CPU (an example of a control unit) 61 of the microcomputer 60 will be described. Here, a process of detecting the ammonia concentration in the measurement gas using the first ammonia electromotive force EMF1, the first pumping current Ip1, and the like detected by the first ammonia sensor unit 42x will be described.
Fig. 4 is a flowchart showing the content of the ammonia concentration detection process. First, in the multi-gas sensor device 400 (see fig. 2), the first ammonia electromotive force EMF1 (an example of the first detection result) output from the first ammonia sensor unit 42x is detected via the first electromotive force detection circuit 58a, and information on the first ammonia electromotive force EMF1 is received by the microcomputer 60 of the gas sensor control device 300 (first receiving process, step 1 of fig. 4).
On the other hand, the first pumping current Ip1 (an example of the second detection result) output from the first pumping unit 2 is detected via the Ip1 driver circuit 52, and information on the first pumping current Ip1 is received by the microcomputer 60 (second receiving process, step 1 of fig. 4). As the first pumping current Ip1, a current detected at the same timing (at the same time) as the timing of detecting the first ammonia electromotive force is used.
When information on the first pumping current Ip1 is input to the CPU 61 of the microcomputer 60, the CPU 61 calls up "the first pumping current Ip1-O 2 concentration output relation" from the ROM 63, and converts the first pumping current Ip into the first oxygen concentration Y (an example of the second detection result) using the relation (output conversion processing, step 2 of fig. 4).
Next, the CPU 61 calls out "first ammonia electromotive force & O 2 concentration output-ammonia concentration output relation" from the ROM 63, and calculates a first ammonia concentration that is a tentative ammonia concentration without reducing (without taking into consideration) the influence of the pressure of the measured gas, using the relation, the first ammonia electromotive force EMF1, and the first oxygen concentration Y (first concentration calculation process, step 3 of fig. 4).
Then, the CPU 61 acquires pressure information of the exhaust gas (measured gas) from the ECU 220 as an external device (pressure information acquisition process, step 4 of fig. 4). Here, a pressure sensor 500 that detects the pressure of the measured gas and the like will be described with reference to fig. 5. Fig. 5 is an explanatory diagram showing an installation site of the pressure sensor 500 for detecting the pressure of the measured gas. In fig. 5, an oxidation catalyst 503, a DPF (Diesel Particulate Filter: diesel particulate filter) 504, and an SCR (SELECTIVE CATALYTIC Reduction: selective catalytic Reduction) catalyst 505 are provided in this order from the upstream side in the middle of an exhaust pipe 502 of a diesel engine (internal combustion engine) 501. The pressure sensor 500 is provided in the exhaust pipe 502 at a position between the DPF 504 and the SCR catalyst 505, and detects the pressure of the exhaust gas (measured gas) flowing in the exhaust pipe 502. The multi-gas sensor 200A of the multi-gas sensor device 400 is provided at a position on the downstream side of the exhaust pipe 502 adjacent to the SCR catalyst 505.
The pressure (measured value) detected by the pressure sensor 500 is stored in a memory device (ROM such as EPROM or EEPROM) provided in the ECU 220. The CPU 61 of the gas sensor control device 300 (microcomputer 60) executes processing of acquiring information on the pressure detected by the pressure sensor 500 from such ECU 220. The pressure information of the measured gas obtained by the microcomputer 60 is the absolute pressure (101.325+p) (P is the measured value of the pressure sensor 500). As the pressure information of the pressure sensor 500, pressure information detected at the same timing (at the same time) as the timing at which the first ammonia electromotive force EMF1 is detected, or pressure information detected after a predetermined time from the timing at which the first ammonia electromotive force EMF1 is detected is used.
Next, as shown in fig. 4, in order to reduce the influence of the pressure of the measured gas, the CPU 61 executes a process of calculating a correction coefficient Z' for correcting the first ammonia concentration (correction coefficient calculation process, step 5 of fig. 4). Here, first, the first oxygen concentration Y is pressure-corrected to obtain the second oxygen concentration Y'. Specifically, for example, the second oxygen concentration Y' is calculated based on the following relational expression (1) and the first oxygen concentration Y.
[ Relation (1) ]
Y’＝Y×(101.325+P+k)/(101.325+P)×101.325/(101.325+k)
(In the above formula, P is a measured value (measured pressure) of the measured gas, and k is a pressure correction coefficient.)
Next, a temporary correction coefficient Z is calculated based on the second oxygen concentration Y' and the following relational expression (2).
[ Relation (2) ]
Z＝a×Y’＾2+b×Y’+c
(Wherein a, b and c in the above formula are each a coefficient.)
When the temporary correction coefficient Z is corrected, a correction coefficient Z' for correcting the first ammonia concentration is obtained. Specifically, the correction coefficient Z' for correcting the first ammonia concentration is obtained, for example, based on the following relational expression (3) and the temporary correction coefficient Z.
[ Relation (3) ]
Z’＝Z×((101.325+P+k’)/(101.325+P)×101.325/(101.325+k’))×(a×ln(Y’)+b)
(In the above formula, P is a measured value (measured pressure) of the measured gas, k' is a pressure correction coefficient, and a and b are coefficients respectively.)
Next, as shown in step 6 of fig. 4, the following processing (pressure correction processing) is performed in the CPU 61: the first ammonia concentration is corrected by a correction coefficient Z' based on the pressure information of the measured gas, and the second ammonia concentration of the measured gas is obtained. Here, the correction coefficient Z' is multiplied (multiplied) by the first ammonia concentration to obtain a second ammonia concentration in which the influence of the pressure of the measured gas is reduced. In this way, the second ammonia concentration that reduces the influence of the pressure of the measured gas can be easily obtained.
In the present embodiment, as shown in fig. 2, the first pumping means 2 pumps out or draws in oxygen in the gas to be measured (exhaust gas) introduced from the outside (inside the exhaust pipe) through the protective layer 9 made of porous material and the first diffusion resistor 8a in the first measurement chamber S1. Therefore, the first pumping current Ip1 output from the first pumping unit 2 is affected by the pressure of the measured gas. Therefore, in the present embodiment, as shown in step 7 of fig. 4, in order to reduce the influence of such pressure on oxygen, for example, the following process (oxygen pressure correction process) is performed: the second ammonia concentration is corrected based on the pressure information of the measured gas. As a result of this treatment, the third ammonia concentration of the measured gas is obtained, which reduces the influence of the pressure of the measured gas on oxygen.
As described above, the ammonia concentration (second ammonia concentration, third ammonia concentration) in which the influence of the pressure of the measured gas on ammonia is reduced is obtained by using the first ammonia electromotive force EMF1 (an example of the first detection result), the first pumping current Ip1 (an example of the second detection result), the pressure information of the measured gas, and the like detected by the first ammonia sensor unit 42 x. In addition, the third ammonia concentration reduces the influence of the pressure of the measured gas on the oxygen as well as the influence of the pressure of the measured gas on the ammonia.
In the second ammonia sensor unit 42y, the ammonia concentration (second ammonia concentration) in which the influence of the pressure of the gas to be measured on ammonia is reduced and the ammonia concentration (third ammonia concentration) in which the influence of the pressure of the gas to be measured on both ammonia and oxygen is reduced are obtained by using the second ammonia electromotive force EMF2 (an example of the first detection result), the first pumping current Ip1 (an example of the second detection result), the pressure information of the gas to be measured, and the like.
The NO 2 gas concentration and the like are obtained using the third ammonia concentrations and the like obtained from the first ammonia sensor unit 42x and the second ammonia sensor unit 42 y.
As described above, according to the multi-gas sensor device 400 (gas sensor control device 300) of the present embodiment, the accuracy of measuring the ammonia concentration can be improved by reducing the influence of the pressure of the measured gas on the ammonia. In particular, in the case of the present embodiment, the accuracy of measuring the ammonia concentration can be further improved by reducing the influence of the pressure of the measurement gas on oxygen.
[ Ammonia detection test 1]
The ammonia detection test described below was performed using the multi-gas sensor device 400 of embodiment 1. A predetermined exhaust pipe is prepared, and the multi-gas sensor apparatus 400 is provided in the middle of the exhaust pipe. Then, the pressure conditions of the gas to be measured are changed in a state where the gas to be measured (gas) containing ammonia at a constant concentration is supplied to the exhaust pipe, and the ammonia concentration under each pressure condition is detected by the multi-gas sensor device 400. Here, for the test, the ammonia concentration (first ammonia concentration) which has not been subjected to the pressure correction process and the oxygen correction process and the ammonia concentration (second ammonia concentration) which has been subjected to the pressure correction process and the oxygen correction process described above were set to be detected by the multi-gas sensor device 400.
Fig. 6 is a graph showing a relationship between the pressure of the measured gas and the ammonia concentration affected by the pressure of the measured gas. In FIG. 6, the horizontal axis represents pressure (kPa), and the vertical axis represents ammonia concentration (ppm). As shown in fig. 6, regarding the ammonia concentration (first ammonia concentration) that has not been subjected to the pressure correction process and the oxygen correction process, it is confirmed that the higher the pressure of the measured gas is, the smaller the ammonia concentration is detected as compared with the original value (set value).
[ Oxygen concentration detection test ]
Next, an oxygen concentration detection test described below was performed using the multi-gas sensor device 400 of embodiment 1. An exhaust pipe similar to the ammonia detection test 1 was prepared, and a multi-gas sensor device 400 was provided in the middle of the exhaust pipe. Then, the pressure conditions of the gas to be measured (air) are changed in a state where the gas to be measured (air) containing oxygen at a constant concentration is supplied to the exhaust pipe, and the oxygen concentration under each pressure condition is detected by the multi-gas sensor device 400. Here, for the test, the oxygen concentration (first oxygen concentration Y) obtained by performing the output conversion processing on the first pumping current Ip1 and the second oxygen concentration Y' obtained by performing the pressure correction on the first oxygen concentration Y were set.
Fig. 7 is a graph showing a relationship between the pressure of the measured gas and the oxygen concentration affected by the pressure of the measured gas. In FIG. 7, the horizontal axis represents pressure (kPa), and the vertical axis represents oxygen concentration (ppm). As shown in fig. 7, as for the first oxygen concentration Y, which is not subjected to pressure correction, it was confirmed that the greater the pressure of the measured gas, the greater the oxygen concentration was detected as a value that is larger than the original value (set value).
[ Ammonia detection test 2]
The ammonia detection test described below was performed using the multi-gas sensor device 400 of embodiment 1. A predetermined exhaust pipe is prepared, and the multi-gas sensor apparatus 400 is provided in the middle of the exhaust pipe. Then, in a state where a gas to be measured (air) containing ammonia at a certain concentration is supplied to the exhaust pipe, the pressure conditions of the gas to be measured are changed, and the ammonia concentration under each pressure condition is detected by the multi-gas sensor device 400. Here, for the test, the ammonia concentration (second ammonia concentration) subjected to only the pressure correction process and not subjected to the oxygen correction process and the ammonia concentration (third ammonia concentration) subjected to the pressure correction process and the oxygen correction process were set to be detected by the multi-gas sensor device 400. The pressure conditions of the measured gas are used as the pressure information of the measured gas.
Fig. 8 is a graph showing a relationship between the pressure of the measured gas and the ammonia concentration that reduces only the influence of the pressure of the measured gas on ammonia. The horizontal axis of FIG. 8 represents pressure (kPa), and the vertical axis represents ammonia concentration (ppm). An error of about several ppm was found between the second ammonia concentration, which was subjected to only the pressure correction treatment but was not subjected to the oxygen correction treatment, and the original value (set value) due to the influence of the pressure of the measured gas on oxygen.
< Embodiment 2>
Next, embodiment 2 of the present invention will be described with reference to fig. 9 and 10. In this embodiment, an engine control system 600 for controlling the operation state of an internal combustion engine (for example, a diesel engine) of an automobile is described. Fig. 9 is an explanatory diagram showing a schematic configuration of an internal combustion engine control system 600 according to embodiment 2. The internal combustion engine control system 600 includes the multi-gas sensor device 400 as a sensor for detecting NO x and ammonia in the exhaust gas (measured gas) from the internal combustion engine. The engine control system 600 includes, in addition to the multi-gas sensor device 400, the ECU 221 as an engine control device and the pressure sensor 500 that detects the pressure of the exhaust gas.
The basic structure of the multi-gas sensor apparatus 400 is the same as that of embodiment 1 described above. However, in the present embodiment, the process of detecting the ammonia concentration in the exhaust gas is not performed in the gas sensor control device 300 provided in the multi-gas sensor device 400, but is performed in the ECU (engine control device) 221 provided in the engine control system 600. The ECU 221 includes a CPU (an example of a control unit) 222, a ROM 223, a RAM 224, a signal input/output unit 225, an a/D converter 226, a timer, and the like. In the case of the present embodiment, various data, programs, and the like necessary for detection of the ammonia concentration and the like are stored in the ROM 223 of the ECU 221, and various processes are executed in the CPU 222.
In addition, the ECU 221 is electrically connected to the gas sensor control device 300 of the multi-gas sensor device 400. The ECU 221 appropriately acquires (receives) various information necessary for performing the ammonia concentration detection process, such as the first ammonia electromotive force EMF1, the second ammonia electromotive force EMF2, the first pumping current Ip1 detected by the first pumping unit 2, and the like, detected by the ammonia sensor portion 42 (the first ammonia sensor portion 42x, the second ammonia sensor portion 42 y) of the multi-gas sensor device 400, from the microcomputer (SCU) 60.
The pressure sensor 500 is provided in the exhaust pipe 502 at a position between the DPF504 and the SCR catalyst 505 (see fig. 5) in the same manner as in embodiment 1. The detection result of the pressure sensor 500 is stored in a ROM (EPROM, EEPROM, etc.) 223 of the ECU 221. The CPU 222 of the ECU 221 also retrieves the pressure information of the measured gas from the ROM 223 as needed. In this way, the ECU 221 acquires pressure information (detection result) of the measured gas from the pressure sensor 500 as an external device.
Here, a process of detecting the ammonia concentration in the measured gas by using the first ammonia electromotive force EMF1, the first pumping current Ip1, and the like detected by the first ammonia sensor portion 42x of the multi-gas sensor device 400 will be described.
Fig. 10 is a flowchart showing the content of the ammonia concentration detection process in the ECU 221. As shown in steps 11 to 13 of fig. 10, the CPU 222 of the ECU 221 executes the same processes as those of embodiment 1 described above, except for executing the processes, to obtain the first ammonia concentration.
In step 14 of fig. 10, the CPU 222 reads out the pressure information of the exhaust gas (measured gas) stored in the ROM 223 and detected by the pressure sensor 500, and thereby acquires the pressure information (absolute pressure) of the exhaust gas.
As shown in steps 15 to 17 of fig. 10, the CPU 222 of the ECU 221 executes the same processes as those of embodiment 1 described above, except that the processes are executed, and finally, a third ammonia concentration is obtained in which both the influence of the pressure of the measured gas on ammonia and the influence of the pressure of the measured gas on oxygen are reduced.
As described above, the ECU 221 may perform the ammonia concentration detection process similar to that of embodiment 1.
< Embodiment 3>
Next, embodiment 3 of the present invention will be described with reference to fig. 11 and the like. In this embodiment, as in embodiment 1, a detection process for the ammonia concentration in the measured gas is performed in a microcomputer (SCU) of the multi-gas sensor device. However, in the ammonia concentration detection process of the present embodiment, the pressure correction process is performed to reduce the influence of the pressure of the measured gas on ammonia, but the oxygen pressure correction is not performed in consideration of the influence of the pressure of the measured gas on oxygen.
Fig. 11 is a flowchart showing the content of the ammonia concentration detection process according to embodiment 3. As shown in steps 21 to 24 of fig. 11, the same processes as those in steps 1 to 4 (see fig. 4) of embodiment 1 are executed by the CPU of the microcomputer (SCU).
In addition, as shown in step 25 of fig. 11, in the case of the present embodiment, the correction coefficient Z' is calculated in the same manner as in step 5 of embodiment 1. However, in the case of the present embodiment, since the influence of the pressure of the measured gas on oxygen is not considered, the pressure correction of the first oxygen concentration Y obtained by the above-described relational expression (1) for calculating the temporary correction coefficient Z is not performed. Therefore, "(second oxygen concentration) Y'" in the above-described relational expression (2) for calculating the temporary correction coefficient Z is replaced with "(first oxygen concentration) Y". In addition, in the above-described relational expression (3) for calculating the correction coefficient Z ', the "(second oxygen concentration) Y'" is also replaced with the "(first oxygen concentration) Y".
As shown in step 26 of fig. 11, the first ammonia concentration is corrected by using the correction coefficient Z' in the same manner as in step 6 of embodiment 1, to obtain a second ammonia concentration in which the influence of the pressure of the measured gas on ammonia is reduced.
As described above, the pressure correction process for reducing the influence of the pressure of the gas to be measured on the ammonia may be performed without considering the influence of the pressure of the gas to be measured on the oxygen (step 26).
The first pumping means of the multi-gas sensor device according to the present embodiment pumps out or pumps in oxygen in the gas to be measured (exhaust gas) introduced from the outside (inside the exhaust pipe) through the protective layer made of porous material and the first diffusion resistor in the first measuring chamber, as in embodiment 1. In contrast, in other embodiments, for example, in the case where the first measurement chamber is directly connected to the outside without passing through the first diffusion resistor or the like, the influence of the pressure of the gas to be measured on oxygen is not required to be considered. Therefore, oxygen pressure correction processing for reducing the influence of the pressure of the measured gas on oxygen may be performed as needed.
< Embodiment 4>
Next, embodiment 4 of the present invention will be described with reference to fig. 12 and the like. In the present embodiment, as in embodiment 2, an ECU (internal combustion engine control device) performs a process of detecting the ammonia concentration in the exhaust gas. In the ammonia concentration detection process of the present embodiment, only the pressure correction process for the purpose of reducing the influence of the pressure of the measured gas on ammonia is performed as in embodiment 3.
Fig. 12 is a flowchart showing the content of the ammonia concentration detection process according to embodiment 4. As shown in steps 31 to 33 of fig. 12, the CPU of the ECU executes the same processes as those of embodiment 3 described above, in addition to the processes, to obtain the first ammonia concentration.
In step 34 of fig. 12, the CPU of the ECU obtains pressure information (absolute pressure) of the exhaust gas (measured gas) detected by the pressure sensor by calling up the pressure information of the exhaust gas (measured gas) stored in the ROM (EPROM, EEPROM, etc.) of the ECU (the same as step 14 of embodiment 2 of fig. 10).
As shown in steps 35 and 36 of fig. 12, the CPU of the ECU executes the same processes as those of embodiment 3 above, in addition to the processes, to finally obtain a second ammonia concentration in which the influence of the measured gas pressure on ammonia is reduced.
As described above, the ECU (internal combustion engine control device) may perform the ammonia concentration detection process similar to that of embodiment 4.
< Embodiment 5>
Next, embodiment 5 of the present invention will be described with reference to fig. 13 and the like. In this embodiment, as in embodiment 1, a detection process for the ammonia concentration in the measured gas is performed in a microcomputer (SCU) of the multi-gas sensor device. However, in the ammonia concentration detection process of the present embodiment, the correction process is performed while bringing together the reduction of the influence of the pressure of the measured gas on ammonia and the reduction of the influence of the pressure of the measured gas on oxygen.
Fig. 13 is a flowchart showing the content of the ammonia concentration detection process according to embodiment 5. As shown in steps 41 to 44 of fig. 13, the same processes as those in steps 1 to 4 (see fig. 4) of embodiment 1 are executed by the CPU of the microcomputer (SCU).
In the present embodiment, the simultaneous correction process is performed in step 45 of fig. 13 instead of steps 5 to 7 (the pressure correction process, the oxygen pressure correction process, and the like of fig. 4) of embodiment 1. In the simultaneous correction process, the simultaneous correction coefficient α for reducing the influence of the pressure of the measurement target gas on ammonia and reducing the influence of the pressure of the measurement target gas on oxygen is obtained based on the pressure information (absolute pressure) of the exhaust gas (measurement target gas) acquired in step 44.
For example, the simultaneous correction coefficient α is obtained using a relational expression determined based on the results of the ammonia detection test 1, the ammonia detection test 2, the oxygen detection test, and the like. Then, the first ammonia concentration calculated in step 43 is corrected using the simultaneous correction coefficient α, whereby a fourth ammonia concentration is obtained in which both the influence of the pressure of the measured gas on ammonia and the influence of the pressure of the measured gas on oxygen are reduced.
As described above, the reduction of the influence of the pressure of the gas to be measured on ammonia and the reduction of the influence of the pressure of the gas to be measured on oxygen can be performed in one step. By thus concentrating the correction process for the first ammonia concentration in one step, the load of the process in the CPU can be suppressed.
< Embodiment 6>
Next, embodiment 6 of the present invention will be described with reference to fig. 14 and the like. In the present embodiment, as in embodiment 2, an ECU (internal combustion engine control device) performs a process of detecting the ammonia concentration in the exhaust gas. In the ammonia concentration detection process of the present embodiment, the simultaneous correction process is performed in which the reduction of the influence of the pressure of the measured gas on ammonia and the reduction of the influence of the pressure of the measured gas on oxygen are performed together, as in embodiment 5.
Fig. 14 is a flowchart showing the content of the ammonia concentration detection process according to embodiment 6. As shown in steps 51 to 54 of fig. 14, the CPU of the ECU executes the same processes as those in steps 11 to 14 (see fig. 10) of embodiment 2.
In this embodiment, in step 55 of fig. 14, the CPU of the ECU performs the same simultaneous correction process as in embodiment 5 to obtain a fourth ammonia concentration in which both the influence of the pressure of the measured gas on ammonia and the influence of the pressure of the measured gas on oxygen are reduced.
As described above, the ECU (internal combustion engine control device) may perform the ammonia concentration detection process similar to that of embodiment 5.
< Other embodiments >
The present invention is not limited to the embodiments described above and illustrated in the drawings, and, for example, the following embodiments are also included in the technical scope of the present invention.
(1) In the above embodiments, the diesel engine is exemplified as the internal combustion engine, but the gas sensor control device, the gas sensor device, and the internal combustion engine control device of the present invention may be applied to, for example, a gasoline engine.
(2) In the above embodiments, the multi-gas sensor device including the two mixed-potential ammonia sensor units has been described, but the present invention is not limited to this, and the present invention can be applied to, for example, a gas sensor device including one mixed-potential ammonia sensor unit.
(3) In the above embodiments, the pressure sensor provided in the exhaust pipe at a position between the DPF and the SCR catalyst is used, but the present invention is not limited to this, and pressure sensors disposed in other positions may be used.
(4) In the above embodiments, the multi-gas sensor device including the oxygen detecting portion and the ammonia detecting portion (that is, the device in which the oxygen detecting portion and the ammonia detecting portion are integrated) is used, but the present invention is not limited to this, and for example, the oxygen detecting portion and the ammonia detecting portion may be configured as separate devices.
(5) In the above embodiments, the correction coefficient Z' calculated by using the relational expressions (1) to (3) and the like is used for the pressure information of the measured gas in the process (pressure correction process) for reducing the influence of the pressure of the measured gas on the ammonia, but the present invention is not limited to this, and in other embodiments, for example, the relation between the first ammonia concentration and the pressure of the measured gas may be prepared in advance in the form of a table, and the pressure correction process may be performed using the table. In addition, the oxygen pressure correction process and the simultaneous correction process may be performed by using a table prepared in advance.
Claims (11)
1. A gas sensor control device is provided with a control unit that performs the following processing:
A first receiving process of receiving a first detection result corresponding to a concentration of ammonia outputted from an ammonia detection unit of a mixed potential system for detecting ammonia contained in a gas to be measured;
a second receiving process of receiving a second detection result corresponding to a concentration of oxygen outputted from an oxygen detecting unit for detecting oxygen contained in the gas to be measured;
a first concentration calculation process of calculating a first ammonia concentration contained in the measured gas based on the first detection result and the second detection result; and
And a pressure correction process for correcting the first ammonia concentration based on pressure information indicating the pressure of the measured gas obtained from an external device to obtain a second ammonia concentration of the measured gas so as to reduce the influence of the pressure of the measured gas on the ammonia.
2. The gas sensor control device according to claim 1, wherein,
The pressure correction process is a process of obtaining the second ammonia concentration by correcting the first ammonia concentration using a correction coefficient based on the pressure information.
3. A gas sensor control device according to claim 1 or 2, wherein,
When the oxygen is affected by the pressure of the gas to be measured, the control unit executes an oxygen pressure correction process for correcting the second ammonia concentration based on the pressure information of the gas to be measured to obtain a third ammonia concentration of the gas to be measured, so as to reduce the effect of the pressure.
4. A gas sensor control device according to claim 1 or 2, wherein,
In the case where the oxygen is affected by the pressure of the gas to be measured, the control unit performs a simultaneous correction process in which a first ammonia concentration is corrected based on the pressure information of the gas to be measured to obtain a fourth ammonia concentration of the gas to be measured, instead of the pressure correction process, in order to reduce the influence of the pressure of the gas to be measured on the ammonia and reduce the influence of the pressure of the gas to be measured on the oxygen.
5. A gas sensor control device according to claim 3, wherein,
In the case where the oxygen is affected by the pressure of the gas to be measured, the control unit performs a simultaneous correction process in which a first ammonia concentration is corrected based on the pressure information of the gas to be measured to obtain a fourth ammonia concentration of the gas to be measured, instead of the pressure correction process, in order to reduce the influence of the pressure of the gas to be measured on the ammonia and reduce the influence of the pressure of the gas to be measured on the oxygen.
6. A gas sensor device is provided with:
A mixed potential ammonia detection unit for detecting ammonia contained in a gas to be measured;
an oxygen detection unit for detecting oxygen contained in the measurement gas; and
The gas sensor control device according to any one of claims 1 to 5.
7. An internal combustion engine control device for controlling an operation state of an internal combustion engine, the internal combustion engine control device comprising a control section that executes:
A first receiving process of receiving a first detection result corresponding to a concentration of ammonia detected by an ammonia detection unit of a mixed potential system for detecting the ammonia contained in a gas to be measured from the internal combustion engine;
a second receiving process of receiving a second detection result corresponding to a concentration of oxygen outputted from an oxygen detecting unit for detecting oxygen contained in the gas to be measured;
a first concentration calculation process of calculating a first ammonia concentration contained in the measured gas based on the first detection result and the second detection result; and
And a pressure correction process for correcting the first ammonia concentration based on pressure information indicating the pressure of the measured gas obtained from an external device to obtain a second ammonia concentration of the measured gas so as to reduce the influence of the pressure of the measured gas on the ammonia.
8. The control device for an internal combustion engine according to claim 7, wherein,
The pressure correction process is a process of obtaining the second ammonia concentration by correcting the first ammonia concentration using a correction coefficient based on the pressure information.
9. The control device for an internal combustion engine according to claim 7 or 8, wherein,
When the oxygen is affected by the pressure of the gas to be measured, the control unit executes an oxygen pressure correction process for correcting the second ammonia concentration based on the pressure information of the gas to be measured to obtain a third ammonia concentration of the gas to be measured, so as to reduce the effect of the pressure.
10. The control device for an internal combustion engine according to claim 7 or 8, wherein,
In the case where the oxygen is affected by the pressure of the gas to be measured, the control unit performs a simultaneous correction process in which a first ammonia concentration is corrected based on the pressure information of the gas to be measured to obtain a fourth ammonia concentration of the gas to be measured, instead of the pressure correction process, in order to reduce the influence of the pressure of the gas to be measured on the ammonia and reduce the influence of the pressure of the gas to be measured on the oxygen.
11. The control device for an internal combustion engine according to claim 9, wherein,
In the case where the oxygen is affected by the pressure of the gas to be measured, the control unit performs a simultaneous correction process in which a first ammonia concentration is corrected based on the pressure information of the gas to be measured to obtain a fourth ammonia concentration of the gas to be measured, instead of the pressure correction process, in order to reduce the influence of the pressure of the gas to be measured on the ammonia and reduce the influence of the pressure of the gas to be measured on the oxygen.
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| JP2020125048A JP7252921B2 (en) | 2019-09-13 | 2020-07-22 | Gas sensor control device, gas sensor device and internal combustion engine control device |
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| JP7252921B2 (en) | 2023-04-05 |
| CN112505127A (en) | 2021-03-16 |
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