WO2013114815A1 - ガスセンサ制御装置及び内燃機関の制御装置 - Google Patents
ガスセンサ制御装置及び内燃機関の制御装置 Download PDFInfo
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- WO2013114815A1 WO2013114815A1 PCT/JP2013/000285 JP2013000285W WO2013114815A1 WO 2013114815 A1 WO2013114815 A1 WO 2013114815A1 JP 2013000285 W JP2013000285 W JP 2013000285W WO 2013114815 A1 WO2013114815 A1 WO 2013114815A1
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/30—Controlling fuel injection
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/14—Introducing closed-loop corrections
- F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
- F02D41/1439—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the position of the sensor
- F02D41/1441—Plural sensors
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/14—Introducing closed-loop corrections
- F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
- F02D41/1444—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases
- F02D41/1454—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases the characteristics being an oxygen content or concentration or the air-fuel ratio
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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
- G01N27/403—Cells and electrode assemblies
- G01N27/406—Cells and probes with solid electrolytes
- G01N27/4065—Circuit arrangements specially adapted therefor
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/14—Introducing closed-loop corrections
- F02D41/1401—Introducing closed-loop corrections characterised by the control or regulation method
- F02D2041/1413—Controller structures or design
- F02D2041/1431—Controller structures or design the system including an input-output delay
Definitions
- the present disclosure includes Japanese application number 2012-22262 filed on February 3, 2012, Japanese application number 2012-22472 filed on February 3, 2012, and filed on October 2, 2012. This is based on Japanese Patent Application No. 2012-220691, which is incorporated herein by reference.
- the present disclosure relates to a gas sensor control device including a gas sensor that detects a concentration of a predetermined component contained in a gas to be detected and an internal combustion engine control device.
- an exhaust gas purification catalyst is installed in an exhaust pipe, and the exhaust gas air-fuel ratio is upstream of the catalyst or both upstream and downstream of the catalyst.
- an exhaust gas sensor air / fuel ratio sensor or oxygen sensor
- the exhaust gas purification rate of the catalyst is increased by feedback control of the air / fuel ratio based on the output of the exhaust gas sensor.
- Patent Document 1 Japanese Patent Publication No. 8-20414
- the auxiliary electrochemical cell is installed in the gas sensor.
- Patent Document 2 JP 59-215935 A
- Patent Document 3 JP 59-226251 A
- Patent Document 4 JP 60-98141 A
- a gas sensor oxygen sensor
- a current supply unit an electric current is supplied from the reference electrode to the measurement electrode by a current supply unit, whereby an output characteristic line of the gas sensor There is something that shifts in the lean direction.
- Patent Document 2 As a countermeasure, in Patent Document 2, a voltage Vi proportional to the current Is flowing between the electrodes of the gas sensor is multiplied by a constant K to obtain an output voltage fluctuation (K ⁇ Vi) due to an internal resistance. The output of the gas sensor is corrected using (K ⁇ Vi).
- Patent Document 3 a voltage Vi proportional to a current Is flowing between electrodes of a gas sensor is multiplied by a constant K to obtain an output voltage fluctuation (K ⁇ Vi) due to an internal resistance, and this output voltage fluctuation (K ⁇ Vi). ) Is used to correct the comparison reference value for air-fuel ratio control (a value corresponding to the target air-fuel ratio).
- the reference value for air-fuel ratio control (a value corresponding to the target air-fuel ratio) is corrected using Vc.
- the problem to be solved by the present invention is that the output characteristics of the gas sensor can be changed without causing a significant design change or cost increase of the gas sensor, and the output voltage fluctuation due to the internal resistance of the gas sensor at the time of current supply. This is to prevent the occurrence of malfunctions.
- a gas sensor control device including a gas sensor that detects a concentration of a predetermined component contained in a gas to be detected by a sensor element in which a solid electrolyte body is disposed between a pair of sensor electrodes.
- a constant current supply unit that changes the output characteristics of the gas sensor by passing a constant current between the electrodes, and when the current value flowing between the sensor electrodes switches, based on the output of the gas sensor before and after the switching, between the sensor electrodes
- An output voltage fluctuation information calculation unit that calculates the output voltage fluctuation amount of the gas sensor at the time of constant current supply for supplying a constant current or information correlated therewith (hereinafter collectively referred to as “output voltage fluctuation information”); It is a configuration.
- the output characteristics of the gas sensor can be changed by flowing a constant current between the sensor electrodes by the constant current supply unit.
- the output characteristics of the gas sensor can be changed without causing a significant design change or cost increase of the gas sensor.
- the output voltage fluctuation information of the gas sensor at the time of constant current supply (output voltage fluctuation due to internal resistance or information correlated therewith) is output. Since it can be calculated by the voltage fluctuation information calculation unit, control based on the output of the gas sensor can be performed taking into account the output voltage fluctuation information, which is caused by fluctuations in the output voltage due to the internal resistance of the gas sensor during constant current supply It is possible to prevent the occurrence of malfunctions.
- the output voltage fluctuation information is calculated based on the output of the gas sensor before and after the switching. Therefore, depending on the individual difference (manufacturing variation) of the gas sensor, deterioration with time, temperature, etc. Even if the internal resistance changes and the output voltage fluctuation due to the internal resistance changes, the output voltage fluctuation information corresponding to the internal resistance at that time can be accurately obtained.
- the output voltage fluctuation information is calculated based on the output of the gas sensor before and after the switching of the current value of the constant current (DC current) flowing between the sensor electrodes instead of supplying an alternating current, the capacitance of the gas sensor
- the output voltage fluctuation information corresponding to the internal resistance can be obtained accurately without being affected, and it is not necessary to provide a circuit for supplying an alternating current, a band-pass filter or the like, and the circuit configuration can be simplified. .
- a determination unit for determining whether or not a predetermined current switching permission condition is satisfied is provided, and when the current switching permission condition is determined to be satisfied, the current value flowing between the sensor electrodes is switched and output. It is preferable to perform calculation of voltage fluctuation information. In this way, when the current switching permission condition is satisfied and the state suitable for the calculation of the output voltage fluctuation information (for example, the state where the output of the gas sensor is stable), the value of the current flowing between the sensor electrodes is switched. The output voltage fluctuation information can be calculated, and the calculation accuracy of the output voltage fluctuation information can be improved.
- the present disclosure may be applied to a system including a sensor that detects a rich / lean air-fuel ratio of exhaust gas from an internal combustion engine as a gas sensor.
- the current switching permission condition is satisfied when the output of the gas sensor is stable on the rich side or the lean side.
- the value of the output voltage fluctuation information can be calculated by switching the value of the current flowing between the sensor electrodes.
- the current switching permission condition is satisfied during the fuel cut for stopping the fuel injection of the internal combustion engine.
- the lean gas flows into the exhaust pipe and the exhaust pipe enters a lean state. Therefore, if it is determined that the current switching permission condition is satisfied during the fuel cut, the output of the gas sensor during the fuel cut When a stable state is achieved on the lean side, the value of the output voltage fluctuation information can be calculated by switching the value of the current flowing between the sensor electrodes.
- the value of the output voltage fluctuation information can be calculated by switching the current value flowing between the sensor electrodes.
- the current switching permission condition is satisfied during the fuel increase control for increasing the fuel injection amount of the internal combustion engine.
- the rich gas flows into the exhaust pipe and the exhaust pipe becomes rich. Therefore, if it is determined that the current switching permission condition is satisfied during the fuel increase control, the gas sensor is being controlled during the fuel increase control.
- the value of the output voltage fluctuation information can be calculated by switching the current value flowing between the sensor electrodes.
- an abnormality diagnosis unit that performs abnormality diagnosis for determining whether there is an abnormality in the constant current supply unit based on the output voltage fluctuation information may be provided.
- an abnormality for example, a failure
- the behavior of the gas sensor output when the value of the current flowing between the sensor electrodes changes is different from the normal value.
- abnormality diagnosis is performed to determine whether there is an abnormality in the constant current supply unit, thereby accurately determining whether there is an abnormality in the constant current supply unit.
- the abnormality of the constant current supply unit occurs, the abnormality can be detected at an early stage.
- control device for an internal combustion engine including the above-described gas sensor control device and a control unit that executes control of the internal combustion engine based on the output of the gas sensor
- the output of the gas sensor is calculated based on the output voltage fluctuation information when the constant current is supplied.
- a sensor output correction unit for correction may be provided, and the control may be performed using the output of the gas sensor corrected by the sensor output correction unit. In this way, control based on the output of the gas sensor can be performed with high accuracy without being affected by fluctuations in the output voltage due to the internal resistance of the gas sensor when supplying a constant current.
- the DC resistance value of the gas sensor is calculated as the output voltage fluctuation information
- the output voltage fluctuation is obtained from the constant current value and DC resistance when the constant current is supplied
- the output of the gas sensor is corrected using the output voltage fluctuation. It is good to do. In this way, even when the constant current value at the time of constant current supply is changed according to the operating state of the internal combustion engine, for example, the output voltage fluctuation (output voltage) is calculated from the constant current value at the time of constant current supply and the DC resistance value.
- the output of the gas sensor can be accurately corrected using the output voltage fluctuation.
- a prohibition unit for prohibiting correction of the gas sensor output by the sensor output correction unit may be provided. In this way, it is possible to prevent the output of the gas sensor from being corrected based on the output voltage fluctuation information deviating from the normal range due to an abnormality in the constant current supply unit.
- the air-fuel ratio is determined based on the output voltage fluctuation information during constant current supply.
- a target value correction unit that corrects a target value for control may be provided, and air-fuel ratio control may be performed using the target value corrected by the target value correction unit. In this way, the air-fuel ratio control based on the output of the gas sensor can be performed with high accuracy without being affected by the output voltage fluctuation due to the internal resistance of the gas sensor when supplying a constant current.
- the DC resistance value of the gas sensor is calculated as output voltage fluctuation information
- the output voltage fluctuation amount is obtained from the constant current value and DC resistance value at the time of constant current supply
- the target value is corrected using the output voltage fluctuation amount. It is good to do so.
- the output voltage fluctuation (output voltage) is calculated from the constant current value at the time of constant current supply and the DC resistance value.
- the amount of decrease or the amount of increase in the output voltage can be obtained with high accuracy, and the target value of the air-fuel ratio control can be accurately corrected using this output voltage fluctuation.
- a prohibition unit that prohibits correction of the target value by the target value correction unit may be provided. In this way, it is possible to prevent the target value of the air-fuel ratio control from being corrected based on the output voltage fluctuation information that is out of the normal range due to the abnormality of the constant current supply unit.
- FIG. 1 is a diagram showing a schematic configuration of an engine control system in Embodiment 1 of the present invention.
- FIG. 2 is a cross-sectional view showing a cross-sectional configuration of the sensor element.
- FIG. 3 is an electromotive force characteristic diagram showing the relationship between the air-fuel ratio (excess air ratio ⁇ ) of exhaust gas and the electromotive force of the sensor element.
- FIG. 4A is a schematic diagram showing the state of gas components around the sensor element.
- FIG. 4B is a schematic diagram showing the state of gas components around the sensor element.
- FIG. 5 is a time chart for explaining the behavior of the sensor output.
- FIG. 6A is a schematic diagram showing the state of gas components around the sensor element.
- FIG. 6B is a schematic diagram showing the state of gas components around the sensor element.
- FIG. 7 is an output characteristic diagram of the oxygen sensor when the lean response / rich response is enhanced.
- FIG. 8 is a flowchart showing the flow of processing of the sensor responsiveness control routine of the first embodiment.
- FIG. 9 is a flowchart showing the flow of processing of the current switching permission determination routine of the first embodiment.
- FIG. 10 is a flowchart showing the flow of processing of the DC resistance value calculation routine of the first embodiment.
- FIG. 11 is a flowchart showing the flow of processing of the sensor output correction routine of the first embodiment.
- FIG. 12 is a flowchart showing the flow of processing of the target voltage correction routine of the second embodiment.
- FIG. 13 is a time chart for explaining an execution example of the abnormality diagnosis permission determination of the third embodiment.
- FIG. 14 is a time chart for explaining an execution example of the abnormality diagnosis of the third embodiment.
- FIG. 15 is a flowchart illustrating a process flow of the abnormality diagnosis permission determination routine according to the third embodiment.
- FIG. 16 is a flowchart showing the flow of processing of the abnormality diagnosis routine of the third embodiment.
- FIG. 17 is a flowchart showing the flow of processing of the abnormality diagnosis permission determination routine of the fourth embodiment.
- FIG. 18 is a flowchart showing the flow of processing of the abnormality diagnosis permission determination routine of the fifth embodiment.
- FIG. 19 is a time chart illustrating an execution example of abnormality diagnosis and sensor output correction according to the sixth embodiment.
- FIG. 20 is a flowchart showing the flow of processing of the abnormality diagnosis and sensor output correction routine of the sixth embodiment.
- Example 1 of the present disclosure will be described with reference to FIGS.
- An intake pipe 12 of an engine 11 that is an internal combustion engine is provided with a throttle valve 13 whose opening is adjusted by a motor or the like, and a throttle opening sensor 14 that detects the opening (throttle opening) of the throttle valve 13. ing.
- a fuel injection valve 15 that performs in-cylinder injection or intake port injection is attached to each cylinder of the engine 11, and a spark plug 16 is attached to each cylinder of the cylinder head of the engine 11. The air-fuel mixture in the cylinder is ignited by the spark discharge of each spark plug 16.
- the exhaust pipe 17 of the engine 11 is provided with an upstream catalyst 18 and a downstream catalyst 19 such as a three-way catalyst for purifying CO, HC, NOx and the like in the exhaust gas.
- an air-fuel ratio sensor 20 that outputs a linear air-fuel ratio signal corresponding to the air-fuel ratio of the exhaust gas is provided as an upstream gas sensor, and the downstream side (upstream side) of the upstream catalyst 18 is provided.
- an oxygen sensor 21 (O 2 sensor) whose output voltage is inverted depending on whether the air-fuel ratio of the exhaust gas is rich or lean with respect to the stoichiometric air-fuel ratio is provided as a downstream gas sensor. It has been.
- this system includes a crank angle sensor 22 that outputs a pulse signal every time a crankshaft (not shown) of the engine 11 rotates by a predetermined crank angle, an air amount sensor 23 that detects an intake air amount of the engine 11, Various sensors such as a cooling water temperature sensor 24 for detecting the cooling water temperature of the engine 11 are provided. Based on the output signal of the crank angle sensor 22, the crank angle and the engine speed are detected.
- the outputs of these various sensors are input to an electronic control unit (hereinafter referred to as “ECU”) 25.
- the ECU 25 is mainly composed of a microcomputer, and executes various engine control programs stored in a built-in ROM (storage medium), so that the fuel injection amount and the ignition timing are determined according to the engine operating state. It functions as a control unit for controlling the throttle opening (intake air amount) and the like.
- the ECU 25 performs upstream detection based on the output (detected air-fuel ratio) of the air-fuel ratio sensor 20 (upstream gas sensor) and the upstream target air-fuel ratio.
- main F / B control for F / B correction of the air-fuel ratio (fuel injection amount) so that the air-fuel ratio of the exhaust gas upstream of the side catalyst 18 becomes the target air-fuel ratio
- the oxygen sensor 21 downstream gas sensor
- the sub F / B control for correcting the F / B correction amount or the fuel injection amount of the main F / B control is performed.
- “F / B” means “feedback” (hereinafter the same).
- the oxygen sensor 21 has a cup-shaped sensor element 31.
- the sensor element 31 is configured to be housed in a housing or an element cover (not shown), and the exhaust of the engine 11 is exhausted. Arranged in the tube 17.
- the solid electrolyte layer 32 (solid electrolyte body) is formed in a cup shape in cross section, an exhaust side electrode layer 33 is provided on the outer surface, and an air side electrode layer 34 is provided on the inner surface. It has been.
- the solid electrolyte layer 32 is made of an oxygen ion conductive oxide that is formed by dissolving CaO, MgO, Y 2 O 3 , Yb 2 O 3 or the like as a stabilizer in ZrO 2 , HfO 2 , ThO 2 , Bi 2 O 3 or the like. Consists of union.
- Each of the electrode layers 33 and 34 is made of a noble metal having high catalytic activity such as platinum, and the surface thereof is subjected to porous chemical plating or the like.
- Electrode layers 33 and 34 form a pair of counter electrodes (sensor electrodes).
- An internal space surrounded by the solid electrolyte layer 32 is an atmospheric chamber 35, and a heater 36 is accommodated in the atmospheric chamber 35.
- the heater 36 has a heat generation capacity sufficient to activate the sensor element 31, and the entire sensor element 31 is heated by the heat generation energy.
- the activation temperature of the oxygen sensor 21 is, for example, about 350 to 400 ° C.
- the atmosphere chamber 35 is maintained at a predetermined oxygen concentration by introducing the atmosphere.
- the outside of the solid electrolyte layer 32 (electrode layer 33 side) is an exhaust atmosphere
- the inside of the solid electrolyte layer 32 (electrode layer 34 side) is an air atmosphere.
- An electromotive force is generated between the electrode layers 33 and 34 in accordance with the difference in partial pressure. That is, the sensor element 31 generates different electromotive force depending on whether the air-fuel ratio is rich or lean.
- the oxygen sensor 21 outputs an electromotive force signal corresponding to the oxygen concentration (that is, the air-fuel ratio) of the exhaust gas.
- the exhaust-side electrode layer 33 of the sensor element 31 is grounded, and the microcomputer 26 is connected to the atmosphere-side electrode layer 34.
- a sensor detection signal corresponding to the electromotive force is output to the microcomputer 26.
- the sensor detection signal (voltage) input to the microcomputer 26 with respect to the electromotive force of the sensor element 31 is offset in the positive direction so that even when a constant current is supplied (when the output characteristics of the oxygen sensor 21 are changed) which will be described later.
- the sensor detection signal input to the microcomputer 26 may change within a positive value region.
- the microcomputer 26 is provided in the ECU 25, for example, and calculates the air-fuel ratio based on the sensor detection signal.
- the microcomputer 26 may calculate the engine rotation speed and the intake air amount based on the detection results of the various sensors described above.
- the actual air-fuel ratio of the exhaust gas changes sequentially, and may change repeatedly, for example, between rich and lean.
- the detection response of the oxygen sensor 21 is low, there is a concern that the engine performance may be affected due to this.
- the amount of NOx in the exhaust gas increases more than intended when the engine 11 is operated at a high load.
- the detection response of the oxygen sensor 21 when the actual air-fuel ratio changes between rich and lean will be described.
- the actual air-fuel ratio the actual air-fuel ratio downstream of the upstream catalyst 18
- the component composition of the exhaust gas changes.
- the output change of the oxygen sensor 21 with respect to the air-fuel ratio after the change is delayed.
- HC or the like that is a rich component remains in the vicinity of the exhaust-side electrode layer 33 immediately after the lean change.
- the output change of the oxygen sensor 21 will be described with reference to the time chart of FIG.
- the sensor output (the output of the oxygen sensor 21) changes between the rich gas detection value (0.9 V) and the lean gas detection value (0 V) according to the change in the actual air-fuel ratio. Change.
- the sensor output changes with a delay with respect to the change in the actual air-fuel ratio.
- the sensor output changes with a delay of TD1 with respect to the change of the actual air-fuel ratio when changing from rich to lean, and the sensor output is delayed with respect to the change of the actual air-fuel ratio when changing from lean to rich. It has come to change.
- the ECU 25 executes a routine shown in FIG. 8 to be described later, so that at least one of the detection response when the air-fuel ratio changes lean and the detection response when the rich change occurs.
- a change request regarding the detection responsiveness of the oxygen sensor 21 is determined, and when it is determined that there is a change request, constant current control is performed based on the change request to detect the oxygen sensor 21 Adjust responsiveness arbitrarily.
- the sensor responsiveness is controlled by passing a current in a predetermined direction between the pair of sensor electrodes (between the exhaust-side electrode layer 33 and the atmosphere-side electrode layer 34), thereby variably controlling the detection responsiveness of the oxygen sensor 21. To do. Specifically, as shown in FIG.
- a constant current circuit 27 as a constant current supply unit is connected to the atmosphere side electrode layer 34, and the supply of the constant current Ics by the constant current circuit 27 is controlled by the microcomputer 26. I am going to do that.
- the microcomputer 26 sets the direction and amount of the constant current Ics flowing between the pair of sensor electrodes, and controls the constant current circuit 27 so that the set constant current Ics flows.
- the constant current circuit 27 supplies the constant current Ics to the atmosphere-side electrode layer 34 in either the forward or reverse direction, and the constant current amount can be variably adjusted. That is, the microcomputer 26 variably controls the constant current Ics by PWM control. In this case, in the constant current circuit 27, the constant current Ics is adjusted according to the duty signal output from the microcomputer 26, and the constant current Ics adjusted in the amount of current is provided between the sensor electrodes (the exhaust side electrode layer 33 and the atmosphere side). Between the electrode layers 34).
- the constant current Ics flowing in the direction of the exhaust side electrode layer 33 ⁇ the atmosphere side electrode layer 34 is a negative constant current ( ⁇ Ics), and flows in the direction of the atmosphere side electrode layer 34 ⁇ the exhaust side electrode layer 33.
- the constant current Ics is a positive constant current (+ Ics).
- a constant current Ics positive constant current Ics
- the reduction reaction is promoted with respect to the lean component (NOx) existing (residual) around the exhaust side electrode layer 33, and accordingly, the lean component is promptly removed. Can be removed.
- the rich component (HC) easily reacts in the exhaust-side electrode layer 33, and as a result, the response of the rich output of the oxygen sensor 21 is improved.
- FIG. 7 is a diagram showing output characteristics (electromotive force characteristics) of the oxygen sensor 21 when increasing the detection response (lean sensitivity) at the time of lean change and when increasing the detection response (rich sensitivity) at the time of rich change. is there.
- the negative constant current Ics is set so that oxygen is supplied from the atmosphere-side electrode layer 34 to the exhaust-side electrode layer 33 through the solid electrolyte layer 32 as described above.
- the output characteristic line shifts to the rich side as shown by the broken line (a) in FIG. More specifically, the output is shifted to the rich side and the electromotive force decreasing side, and a voltage drop occurs in the output of the oxygen sensor 21.
- the sensor output becomes a lean output even if the actual air-fuel ratio is in a rich region near the stoichiometric air-fuel ratio. This means that the detection response at the time of lean change (lean sensitivity) is enhanced as the output characteristic of the oxygen sensor 21.
- the detection responsiveness (rich sensitivity) at the time of rich change is enhanced, a positive constant current is supplied so that oxygen is supplied from the exhaust-side electrode layer 33 to the atmosphere-side electrode layer 34 through the solid electrolyte layer 32 as described above.
- the output characteristic line shifts to the lean side as shown by the broken line (b) in FIG. More specifically, a shift to the lean side and the electromotive force increase side causes a voltage increase in the output of the oxygen sensor 21.
- the sensor output becomes a rich output. This means that the detection response at the time of rich change (rich sensitivity) is enhanced as the output characteristic of the oxygen sensor 21.
- the current value of the constant current (DC current) flowing between the sensor electrodes is switched by executing the routines of FIGS. 9 to 11 described later by the ECU 25 (or the microcomputer 26).
- the output voltage fluctuation information of the oxygen sensor 21 at the time of constant current supply is calculated,
- the output of the oxygen sensor 21 is corrected based on the output voltage fluctuation information.
- the sub F / B control based on the output of the oxygen sensor 21 can be performed in consideration of the output voltage fluctuation information, and the problem caused by the output voltage fluctuation due to the internal resistance of the oxygen sensor 21 when the constant current is supplied. Can be prevented.
- the current switching permission condition is satisfied depending on whether or not the output of the oxygen sensor 21 has dropped below a predetermined value (for example, a value corresponding to the atmospheric state) during fuel cut to stop fuel injection of the engine 11.
- a predetermined value for example, a value corresponding to the atmospheric state
- the current value of the constant current (DC current) flowing between the sensor electrodes is set to I1.
- Is switched from I2 to I2 and the DC resistance value (internal resistance value) of the oxygen sensor 21 is determined as output voltage fluctuation information from the difference (V2-V1) in the output of the oxygen sensor 21 before and after the switching and the difference in current value (I2-I1). Calculate.
- the output voltage fluctuation (output voltage drop or output voltage rise) is calculated from the constant current value and the DC resistance value at that time. And the output of the oxygen sensor 21 is corrected using the output voltage fluctuation.
- the ECU 25 performs sub F / B control using the output of the oxygen sensor 21 after correction.
- the sensor responsiveness control routine shown in FIG. 8 is repeatedly executed at a predetermined cycle during the power-on period of the ECU 25.
- this routine in steps 101 to 103, it is determined whether or not there is a change request for changing the detection responsiveness of the oxygen sensor 21, and in steps 104 to 107, constant current control is performed based on the determination result of the change request.
- the detection responsiveness of the oxygen sensor 21 is changed.
- step 101 it is determined whether or not the engine 11 is in a cold state such as at the time of starting, for example, depending on whether or not one of the following conditions (1) to (3) is satisfied. To do.
- the cooling water temperature of the engine 11 is below a predetermined temperature.
- the oil temperature of the engine 11 (lubricating oil temperature) is below a predetermined temperature.
- the fuel temperature in the fuel path is below a predetermined temperature. If it is determined in step 101 that the engine 11 is in the cold state, it is determined that there is a change request for improving the rich responsiveness (detection responsiveness at the time of rich change). In this case, the process proceeds to step 104, and the supply of the constant current Ics is controlled based on the change request for increasing the rich responsiveness. Specifically, “positive constant current Ics” is set as the constant current of the constant current circuit 27.
- the microcomputer 26 controls the constant current circuit 27, and the constant current Ics (positive constant current Ics) flows in the direction in which oxygen is supplied from the exhaust side electrode layer 33 to the atmosphere side electrode layer 34. Thereby, the rich responsiveness of the oxygen sensor 21 is enhanced when the engine 11 is in a cold state.
- the constant current amount is preferably a predetermined value.
- step 101 determines whether or not the engine 11 is in the cold state. If it is determined in step 101 that the engine 11 is not in the cold state, the process proceeds to step 102 to determine whether or not the engine 11 is in the high load operation state, for example, the following (4) Judgment is made based on whether one of the conditions (6) to (6) is satisfied.
- the amount of air charged into the cylinder is a predetermined amount or more.
- the combustion pressure in the cylinder is a predetermined value or more.
- the accelerator opening is a predetermined value or more.
- the microcomputer 26 controls the constant current circuit 27, and the constant current Ics (negative constant current Ics) flows in the direction in which oxygen is supplied from the atmosphere side electrode layer 34 to the exhaust side electrode layer 33. Thereby, when the engine 11 is in a high load operation state, the lean responsiveness of the oxygen sensor 21 is enhanced.
- the constant current amount is preferably a predetermined value.
- the high load operation period includes a transient time when the engine load changes to an increasing side and a high load steady time when the load increases due to the load increase. It is.
- both the transient response and the high load steady state can improve the lean response, but in order to increase the detection response, the response level required as the detection response is required for the transient and high load steady state. It is better to make them different.
- the response level at the time of transition is set to be higher than the response level at the time of steady high load. That is, when it is determined that the engine 11 is in a high load operation state, it is further determined whether the engine 11 is in a transient state or a high load steady state. It is determined that there is a change request to make the response level relatively small (less than in the high load steady state) while increasing the lean response and determining that it is a transient time. Correspondingly, it is determined that there is a change request to increase the lean responsiveness and relatively increase the responsiveness level (increase the transient level) while determining that the load is steady at high load. It corresponds to that. Then, the supply of the constant current Ics is controlled based on the change request in each of the transition time and the high load steady time.
- step 102 determines whether or not rich injection control for neutralization is being performed.
- the air-fuel ratio is set so as to eliminate the excessive oxygen state (extremely lean atmosphere) of the two catalysts 18, 19. This is air-fuel ratio control that is temporarily enriched.
- the atmosphere of both the catalysts 18 and 19 is neutralized by the enrichment of the fuel injection amount (the state is maintained near the theoretical air-fuel ratio).
- the rich injection control is terminated at the timing when the output of the oxygen sensor 21 shifts from the lean value to the rich value.
- this rich injection control is performed, the detection responsiveness at the time of rich change is lowered.
- step 103 If it is determined in step 103 that the rich injection control is being performed, it is determined that there is a change request for reducing the rich responsiveness (detection responsiveness at the time of rich change). In this case, the process proceeds to step 106, and the supply of the constant current Ics is controlled based on the change request for reducing the rich responsiveness.
- “negative constant current Ics” is set as the constant current of the constant current circuit 27 (the same as the case where the lean responsiveness is enhanced).
- the microcomputer 26 controls the constant current circuit 27, and the constant current Ics (negative constant current Ics) flows in the direction in which oxygen is supplied from the atmosphere side electrode layer 34 to the exhaust side electrode layer 33. Thereby, the rich responsiveness is lowered when the rich injection control is performed.
- the constant current amount is preferably a predetermined value.
- step 101 and 104 the process of increasing the rich response of the oxygen sensor 21 when the engine 11 is cold (steps 101 and 104) and the lean of the oxygen sensor 21 when the engine 11 is in a high load operation state.
- step 102 and 105 the process of increasing the responsiveness
- step 103 and 106 the process of reducing the rich responsiveness of the oxygen sensor 21 when the rich injection control is performed. It is not limited and you may make it implement any one or two.
- the direction of the constant current flowing between the sensor electrodes may be switched to switch between a state in which lean responsiveness is enhanced and a state in which rich responsiveness is enhanced, In this case, you may make it change the magnitude
- the current switching permission determination routine shown in FIG. 9 is repeatedly executed at a predetermined cycle during the power-on period of the ECU 25, and serves as a determination unit. When this routine is started, it is determined in steps 201 to 203 whether or not a current switching permission condition is satisfied.
- step 201 whether or not the sensor element 31 is in an active state, for example, whether or not the element impedance is a predetermined value (for example, 100 ⁇ ) or less, and whether or not the energization time of the heater 36 is a predetermined time or more.
- step 201 If it is determined in step 201 that the sensor element 31 is in the active state, the process proceeds to step 202, where it is determined whether or not the fuel is being cut, and if it is determined that the fuel is being cut.
- step 203 it is determined whether the output of the oxygen sensor 21 is equal to or less than a predetermined value.
- This predetermined value is set to a value (for example, a value of 0.05 V or less) corresponding to the atmospheric condition (lean condition).
- step 301 it is determined whether or not the current switching permission condition is satisfied depending on whether or not the current switching permission flag is on (permitted state).
- step 301 If it is determined in step 301 that the current switching permission flag is off (inhibited state), it is determined that the current switching permission condition is not satisfied, and the processing after step 302 is not executed. End the routine.
- step 301 if it is determined in step 301 that the current switching permission flag is on (permitted state), it is determined that the current switching permission condition is satisfied, and the processing after step 302 is performed as follows. And run.
- the constant current circuit 27 is controlled so that the constant current I1 flows between the sensor electrodes (between the exhaust side electrode layer 33 and the atmosphere side electrode layer 34).
- the constant current I1 is set to 0 mA, for example.
- the constant current flowing between the sensor electrodes is set to 0 mA.
- step 303 the output of the oxygen sensor 21 when the constant current I1 is passed between the sensor electrodes (for example, when the constant current flowing between the sensor electrodes is set to 0 mA) is detected as the sensor output V1 before switching.
- the output of the oxygen sensor 21 is detected a plurality of times, and the average value is set as the sensor output V1 before switching.
- the process proceeds to step 304, and the constant current circuit 27 is controlled so that the constant current I2 flows between the sensor electrodes.
- the constant current I2 is set to a value (for example, 0.1 to 10 mA) that is larger than the AD conversion error and can reliably detect a voltage difference and does not damage the oxygen sensor 21.
- step 305 the output of the oxygen sensor 21 when the constant current I2 is passed between the sensor electrodes is detected as the sensor output V2 after switching.
- the output of the oxygen sensor 21 is detected a plurality of times, and the average value is set as the sensor output V2 after switching.
- step 306 the direct current resistance value (internal resistance value) of the oxygen sensor 21 is calculated from the difference between the output of the oxygen sensor 21 before and after the switching of the current value (V2 ⁇ V1) and the difference between the current values (I2 ⁇ I1). Calculate.
- step 401 it is determined whether or not a constant current supply for passing a constant current between the sensor electrodes is in progress (that is, the output characteristics of the oxygen sensor 21 are being changed). If it is determined that the current is in the middle, the process proceeds to step 402, where the current constant current value and the direct current resistance value (internal resistance value) of the oxygen sensor 21 are used to determine the internal resistance of the oxygen sensor 21 when the constant current is supplied. Calculate the output voltage fluctuation (output voltage drop or output voltage rise) by the following formula.
- Output voltage fluctuation constant current value ⁇ DC resistance value
- the output voltage fluctuation that is, the output voltage drop
- the output voltage fluctuation that is, the output voltage increase
- when a constant current is supplied in the increasing direction of the output voltage of the oxygen sensor 21 is a positive value.
- step 403 the sensor output (the output of the oxygen sensor 21) is corrected by the following equation using the output voltage fluctuation.
- Sensor output sensor output ⁇ output voltage fluctuation component
- the ECU 25 performs sub F / B control using the corrected sensor output (output of the oxygen sensor 21).
- a constant current is caused to flow between the sensor electrodes by the constant current circuit 27 provided outside the oxygen sensor 21, thereby changing the output characteristics of the oxygen sensor 21 to achieve lean responsiveness or rich responsiveness. Can be increased.
- the output characteristics of the oxygen sensor 21 can be changed without causing a significant design change or cost increase.
- the internal resistance of the oxygen sensor 21 causes a voltage fluctuation (voltage drop or voltage rise) in the output of the oxygen sensor 21.
- the DC resistance value (internal resistance value) of the oxygen sensor 21 is calculated from the difference between the output of the oxygen sensor 21 before and after the switching of the current value flowing between the sensor electrodes and the current value.
- the output voltage fluctuation (output voltage drop) is calculated from the constant current value and DC resistance value at the time of constant current supply.
- the sub F / B control based on the output of the oxygen sensor 21 can be accurately performed without being affected by the output voltage fluctuation due to the internal resistance of the oxygen sensor 21, and the output voltage due to the internal resistance of the oxygen sensor 21. It is possible to prevent the exhaust emission from deteriorating by preventing the air-fuel ratio control accuracy from being lowered due to the fluctuation.
- a DC resistance value (internal resistance value) is calculated based on the output of the oxygen sensor 21 before and after the switching, and the DC resistance value (internal resistance value) is calculated. Since the output voltage fluctuation is calculated using the internal resistance due to individual differences (manufacturing variation), deterioration with time, temperature, etc. of the oxygen sensor 21, even if the output voltage fluctuation due to the internal resistance changes, And the output voltage fluctuation corresponding to the internal resistance can be obtained with high accuracy.
- a direct current resistance value (internal resistance value) is calculated based on the output of the oxygen sensor 21 before and after switching the current value of a constant current (direct current) flowing between the sensor electrodes, Since the output voltage fluctuation is calculated using the DC resistance value (internal resistance value), the internal resistance and the output voltage fluctuation corresponding to the internal resistance are accurately obtained without being affected by the capacitance of the oxygen sensor 21.
- the first embodiment it is determined whether or not a predetermined current switching permission condition is satisfied, and the current value flowing between the sensor electrodes is switched when it is determined that the current switching permission condition is satisfied.
- the calculation of the output voltage fluctuation information (the DC resistance value of the oxygen sensor 21 in the first embodiment) is executed, so that the current switching permission condition is satisfied and the state suitable for the calculation of the output voltage fluctuation information (for example, oxygen
- the current value flowing between the sensor electrodes can be switched to calculate the output voltage fluctuation information, and the calculation accuracy of the output voltage fluctuation information can be improved.
- the output of the oxygen sensor 21 is output during the fuel cut.
- the output voltage fluctuation information can be calculated by switching the value of the current flowing between the sensor electrodes.
- the error included in the output of the oxygen sensor 21 is reduced, and the current value flowing between the sensor electrodes is switched.
- the calculation accuracy of the output voltage fluctuation information based on the output of the oxygen sensor 21 can be further improved.
- Embodiment 2 of the present invention will be described with reference to FIG. However, description of substantially the same parts as those in the first embodiment will be omitted or simplified, and different parts from the first embodiment will be mainly described.
- the output of the oxygen sensor 21 is corrected using the output voltage fluctuation obtained from the constant current value and the direct current resistance value when the constant current is supplied.
- the target voltage correction routine of FIG. 12 described later is executed by the computer 26), thereby correcting the target voltage of the sub F / B control using the output voltage fluctuation obtained from the constant current value and the DC resistance value when supplying a constant current.
- the target voltage correction routine of FIG. 12 described later is executed by the computer 26), thereby correcting the target voltage of the sub F / B control using the output voltage fluctuation obtained from the constant current value and the DC resistance value when supplying a constant current.
- the target voltage correction routine shown in FIG. 12 is repeatedly executed at a predetermined cycle during the power-on period of the ECU 25, and serves as a target value correction unit.
- this routine is started, first, in step 501, it is determined whether constant current supply for passing a constant current between the sensor electrodes is in progress (that is, while the output characteristics of the oxygen sensor 21 are being changed). If it is determined that the current is in the middle, the process proceeds to step 502, where the current constant current value and the direct current resistance value (internal resistance value) of the oxygen sensor 21 are used to determine the internal resistance of the oxygen sensor 21 when the constant current is supplied. Calculate the output voltage fluctuation (output voltage drop or output voltage rise) by the following formula.
- Output voltage fluctuation constant current value ⁇ DC resistance value
- the output voltage fluctuation that is, the output voltage drop
- the output voltage fluctuation that is, the output voltage increase
- when a constant current is supplied in the increasing direction of the output voltage of the oxygen sensor 21 is a positive value.
- step 503 the target voltage of the sub F / B control is corrected by the following equation using the output voltage fluctuation.
- Target voltage target voltage + output voltage fluctuation component
- the ECU 25 performs sub F / B control using the corrected target voltage.
- an output voltage fluctuation (output voltage drop or output voltage rise) is obtained from the constant current value and DC resistance value at that time, and this output voltage fluctuation is used. Since the target voltage for sub F / B control is corrected, the constant current value and the DC resistance at the time of constant current supply can be changed even when the constant current value at the time of constant current supply is changed according to the engine operating state, for example.
- the output voltage fluctuation (output voltage drop or output voltage rise) can be accurately obtained from the value, and the target voltage of the sub F / B control can be accurately corrected using the output voltage fluctuation. The same effect as in Example 1 can be obtained.
- the DC resistance value of the oxygen sensor 21 is calculated as the output voltage fluctuation information when the current switching permission condition is satisfied.
- the present invention is not limited to this.
- the constant current value at the time of constant current supply is always fixed to the predetermined value V0 regardless of the state or the like, the current value flowing between the sensor electrodes is changed from 0 to the predetermined value V0 when the current switching permission condition is satisfied. It is also possible to switch to (that is, the same value as the constant current value at the time of constant current supply) and obtain the output voltage fluctuation from the difference in the output of the oxygen sensor 21 before and after the switching.
- Embodiment 3 of the present invention will be described with reference to FIGS. However, description of substantially the same parts as those in the first embodiment will be omitted or simplified, and different parts from the first embodiment will be mainly described.
- the ECU 25 (or the microcomputer 26) executes routines shown in FIGS. 15 and 16 to be described later, thereby determining whether or not the constant current circuit 27 is abnormal (for example, failure). Is executed as follows.
- the abnormality diagnosis execution condition is satisfied, and it is determined that the abnormality diagnosis execution condition is satisfied at the time t1 when the output of the oxygen sensor 21 falls below a predetermined value during the fuel cut.
- the diagnosis permission flag is set to ON (permission state) which means that abnormality diagnosis is permitted. In this case, the abnormality diagnosis execution condition corresponds to the current switching permission condition.
- the abnormality diagnosis permission flag is set to ON (permitted state) (that is, when it is determined that the abnormality diagnosis execution condition is satisfied), between the sensor electrodes
- An abnormality diagnosis is performed.
- the difference ⁇ V in the output of the oxygen sensor 21 corresponds to the output voltage fluctuation information.
- the output of the oxygen sensor 21 when the constant current I1 is passed between the sensor electrodes is detected a plurality of times, and the average value is calculated as the sensor output V1 before switching.
- the current value flowing between the sensor electrodes is switched from I1 to I2 at time t2, and from time t2 to t3, the output of the oxygen sensor 21 when a constant current I2 is passed between the sensor electrodes is detected a plurality of times.
- the average value is calculated and set as the sensor output V2 after switching.
- the sensor output difference ⁇ V before and after switching (the difference between the sensor output V1 before switching and the sensor output V2 after switching) is calculated, and the sensor output difference ⁇ V before and after switching is within a predetermined normal range.
- An abnormality diagnosis of the constant current circuit 27 is performed depending on whether or not there is. When this abnormality diagnosis is completed, the constant current flowing between the sensor electrodes is returned to the original value.
- an abnormality for example, a failure
- the behavior of the output of the oxygen sensor 21 when the value of the current flowing between the sensor electrodes is switched is different from that in the normal state.
- an abnormality diagnosis is performed to determine whether there is an abnormality in the constant current circuit 27 based on whether or not the difference in the output of the oxygen sensor 21 before and after the switching is within a normal range. The presence or absence of an abnormality in the circuit 27 can be determined with high accuracy.
- abnormality diagnosis execution condition After that, after determining that the abnormality diagnosis execution condition is not established and resetting the abnormality diagnosis permission flag to OFF (prohibited state) meaning prohibition of abnormality diagnosis, normal sensor response control (see FIG. 8) is performed. ) Is executed.
- the abnormality diagnosis permission determination routine shown in FIG. 15 is repeatedly executed at a predetermined cycle during the power-on period of the ECU 25, and serves as a determination unit. In steps 601 to 603, it is determined whether or not an abnormality diagnosis execution condition (the same condition as the current switching permission condition described in steps 201 to 203 of the routine of FIG. 9) is satisfied.
- step 601 whether or not the sensor element 31 is in an active state, for example, whether or not the element impedance is a predetermined value (for example, 100 ⁇ ) or less, and whether or not the energization time of the heater 36 is a predetermined time or more.
- step 601 If it is determined in step 601 that the sensor element 31 is in the active state, the process proceeds to step 602, where it is determined whether the fuel is being cut or not, and if it is determined that the fuel is being cut.
- step 603 it is determined whether or not the output of the oxygen sensor 21 is equal to or less than a predetermined value.
- This predetermined value is set to a value (for example, a value of 0.05 V or less) corresponding to the atmospheric condition (lean condition).
- step 603 If all the determinations in steps 601 to 603 are “Yes” (when it is determined that the output of the oxygen sensor 21 has dropped below a predetermined value during the fuel cut), the output of the oxygen sensor 21 is on the lean side. It is determined that the condition is stable, it is determined that the abnormality diagnosis execution condition is satisfied, the process proceeds to step 604, and the abnormality diagnosis permission flag is set to ON (permitted state) which means that abnormality diagnosis is permitted. .
- step 605 the abnormality diagnosis permission flag is set to the abnormality diagnosis. Maintain or reset to off (prohibited state), which means prohibition.
- the abnormality diagnosis routine shown in FIG. 16 is repeatedly executed at a predetermined period during the power-on period of the ECU 25, and plays a role as an output voltage fluctuation information calculation unit and an abnormality diagnosis unit.
- step 701 it is determined whether or not an abnormality diagnosis execution condition is satisfied depending on whether or not the abnormality diagnosis permission flag is on (permitted state).
- step 701 If it is determined in step 701 that the abnormality diagnosis permission flag is off (prohibited state), it is determined that the abnormality diagnosis execution condition is not satisfied, and processing relating to abnormality diagnosis in step 702 and subsequent steps is executed. This routine is terminated.
- step 701 if it is determined in step 701 that the abnormality diagnosis permission flag is on (permitted state), it is determined that the abnormality diagnosis execution condition is satisfied, and processing relating to abnormality diagnosis in and after step 702 is performed. Run as follows:
- step 702 the constant current circuit 27 is controlled so that the constant current I1 flows between the sensor electrodes (between the exhaust side electrode layer 33 and the atmosphere side electrode layer 34).
- the constant current I1 is set to 0 mA, for example.
- the constant current flowing between the sensor electrodes is set to 0 mA.
- step 703 the output of the oxygen sensor 21 when the constant current I1 is passed between the sensor electrodes (for example, when the constant current flowing between the sensor electrodes is set to 0 mA) is detected as the sensor output V1 before switching.
- the output of the oxygen sensor 21 is detected a plurality of times, and the average value is set as the sensor output V1 before switching.
- the sensor output V1 When the response of the output of the oxygen sensor 21 to the change in the current flowing between the sensor electrodes is low, if the sensor output V1 is started after waiting until the output of the oxygen sensor 21 converges, the sensor output V1. It takes a long time to detect. Therefore, detection of the sensor output V1 may be started in step 703 after a predetermined time has elapsed since the constant current circuit 27 was controlled to flow the constant current I1 in step 702. In this way, even when the output responsiveness of the oxygen sensor 21 is low, detection of the sensor output V1 can be started without waiting for the output of the oxygen sensor 21 to converge.
- the process proceeds to step 704, and the constant current circuit 27 is controlled so that the constant current I2 flows between the sensor electrodes.
- the constant current I2 is set to a value (for example, 0.1 to 10 mA) that is larger than the AD conversion error and can reliably detect a voltage difference and does not damage the oxygen sensor 21.
- step 705 the output of the oxygen sensor 21 when the constant current I2 is passed between the sensor electrodes is detected as the sensor output V2 after switching.
- the output of the oxygen sensor 21 is detected a plurality of times, and the average value is set as the sensor output V2 after switching.
- step 704 detection of the sensor output V2 may be started in step 705 after a predetermined time has elapsed since the constant current circuit 27 was controlled to flow the constant current I2. In this way, even when the output responsiveness of the oxygen sensor 21 is low, detection of the sensor output V2 can be started without waiting for the output of the oxygen sensor 21 to converge.
- step 706 a sensor output difference ⁇ V before and after switching (a difference between the sensor output V1 before switching and the sensor output V2 after switching) is calculated.
- step 707 it is determined whether or not the sensor output difference ⁇ V before and after switching is within a predetermined normal range.
- This normal range is set based on, for example, constant currents I1 and I2 before and after switching.
- the normal range is set in consideration of changes in sensor output characteristics caused by changes in the internal resistance of the oxygen sensor 21. That is, the normal range is set to a value that exceeds the change width of the sensor output characteristic caused by the change in the internal resistance of the oxygen sensor 21 (the change exceeding the change in the sensor output characteristic caused by the change in the internal resistance of the oxygen sensor 21 If it occurs, it is determined that the constant current circuit 27 is abnormal).
- step 707 If it is determined in step 707 that the sensor output difference ⁇ V before and after switching is within the normal range, the process proceeds to step 708 and it is determined that the constant current circuit 27 is not abnormal (normal).
- step 707 if it is determined in step 707 that the sensor output difference ⁇ V before and after switching is not within the normal range (that is, out of the normal range), the process proceeds to step 709 and the constant current circuit 27 is abnormal. It is determined that there is (for example, a failure).
- an abnormality flag is set to ON, and a warning lamp (not shown) provided on the instrument panel of the driver's seat is turned on or blinked.
- a warning is displayed on a warning display section (not shown) on the instrument panel of the driver's seat to warn the driver, and the abnormality information (abnormal code, etc.) is stored in a backup RAM (not shown) of the ECU 25, etc. Is stored in a rewritable nonvolatile memory (a rewritable memory that holds stored data even when the ECU 25 is powered off).
- the constant current circuit 27 determines whether the difference in the output of the oxygen sensor 21 before and after the switching is within a predetermined normal range. Since abnormality diagnosis is performed to determine whether there is an abnormality, it is possible to accurately determine whether there is an abnormality in the constant current circuit 27, and when an abnormality occurs in the constant current circuit 28, the abnormality is detected early. can do.
- the third embodiment it is determined whether or not a predetermined abnormality diagnosis execution condition is satisfied, and when it is determined that the abnormality diagnosis execution condition is satisfied, the current value flowing between the sensor electrodes is switched. Therefore, when the abnormality diagnosis execution condition is satisfied and the state is suitable for abnormality diagnosis (for example, the output of the oxygen sensor 21 is stable), the current value flowing between the sensor electrodes
- the abnormality diagnosis can be executed by switching between and the abnormality diagnosis accuracy can be improved.
- the output of the oxygen sensor 21 is output during the fuel cut.
- the abnormality diagnosis execution condition is satisfied.
- the abnormality diagnosis can be executed by switching the current value flowing between the sensor electrodes.
- Embodiment 4 of the present invention will be described with reference to FIG. However, description of substantially the same parts as in the third embodiment will be omitted or simplified, and different parts from the third embodiment will be mainly described.
- the ECU 25 (or the microcomputer 26) executes an abnormality diagnosis permission determination routine shown in FIG. 17 to be described later, whereby the output of the oxygen sensor 21 is obtained with the constant current flowing between the sensor electrodes set to 0 mA.
- a predetermined value for example, a value corresponding to the atmospheric state
- the abnormality diagnosis permission flag is set to ON (permitted state).
- step 801 it is determined whether or not the sensor element 31 is in an active state, and if it is determined that the sensor element 31 is in an active state, the process proceeds to step 802. Then, it is determined whether or not the output of the oxygen sensor 21 is equal to or less than a predetermined value.
- This predetermined value is set to a value (for example, a value of 0.05 V or less) corresponding to the atmospheric condition (lean condition).
- step 802 If it is determined in step 802 that the output of the oxygen sensor 21 is less than or equal to the predetermined value, the process proceeds to step 803 and the constant current circuit 27 is controlled so that the constant current flowing between the sensor electrodes is 0 mA.
- step 804 it is determined again whether the output of the oxygen sensor 21 is equal to or less than a predetermined value. This is because the output of the oxygen sensor 21 is smaller in a state where a constant current is passed between the sensor electrodes than in a state where the constant current is 0 mA, so that the constant current flowing between the sensor electrodes is 0 mA.
- step 804 If it is determined in step 804 that the output of the oxygen sensor 21 is less than or equal to the predetermined value, it is determined that the output of the oxygen sensor 21 is stable on the lean side, and the abnormality diagnosis execution condition is It is determined that the condition is established, and the process proceeds to step 805, where the abnormality diagnosis permission flag is set to ON (permission state).
- step 806 the abnormality diagnosis permission flag is turned off. Maintain (restricted) or reset.
- the output of the oxygen sensor 21 is on the lean side. Since it is determined that the condition is stable and the abnormality diagnosis execution condition is satisfied, when the output of the oxygen sensor 21 is stable on the lean side, the sensor electrode The abnormality diagnosis can be executed by switching the value of the current flowing through the capacitor, and the abnormality diagnosis accuracy can be improved. Further, since it is not necessary to use a signal related to engine control (for example, a fuel cut flag), there is an advantage that the abnormality diagnosis can be completed by the microcomputer 26 for controlling the oxygen sensor.
- a signal related to engine control for example, a fuel cut flag
- Example 5 of the present invention will be described with reference to FIG. However, description of substantially the same parts as in the third embodiment will be omitted or simplified, and different parts from the third embodiment will be mainly described.
- an abnormality diagnosis execution condition is established depending on whether or not a predetermined time has elapsed after the engine is stopped by executing an abnormality diagnosis permission determination routine of FIG. 18 described later by the ECU 25 (or the microcomputer 26).
- an abnormality diagnosis permission flag is set to ON (permitted state). I have to.
- the abnormality diagnosis permission determination routine of FIG. 18 and the abnormality diagnosis routine of FIG. 16 can be executed, and for a while after the IG switch (ignition switch) not shown is turned off, the main relay ( The power supply to the ECU 25 (microcomputer 26) is continued while maintaining the ON state (not shown).
- step 901 it is determined whether or not the sensor element 31 is in an active state. If it is determined that the sensor element 31 is in an active state, the process proceeds to step 902. Then, it is determined whether or not a predetermined time has elapsed since the engine stopped (for example, the IG switch is turned off).
- the predetermined time is set to a time required for the inside of the exhaust pipe 17 to be in substantially the same state (lean state) as the atmosphere.
- step 902 If it is determined in step 902 that a predetermined time has elapsed since the engine stopped, it is determined that the output of the oxygen sensor 21 is stable on the lean side, and the abnormality diagnosis execution condition is satisfied. The process proceeds to step 903, and the abnormality diagnosis permission flag is set to ON (permission state).
- step 904 the abnormality diagnosis permission flag is turned off (prohibited). State) or reset.
- Embodiment 6 of the present invention will be described with reference to FIGS. However, description of substantially the same parts as in the third embodiment will be omitted or simplified, and different parts from the third embodiment will be mainly described.
- the ECU 25 (or the microcomputer 26) executes a routine of FIG. 20 to be described later, thereby executing abnormality diagnosis of the constant current circuit 27 and output correction of the oxygen sensor 21 as follows.
- the output of the oxygen sensor 21 when the constant current I1 is passed between the sensor electrodes is detected as the sensor output V1 before switching.
- the output of the oxygen sensor 21 when the constant current I2 is passed between the sensor electrodes is detected as the sensor output V2 after switching.
- an abnormality diagnosis is performed to determine whether or not the constant current circuit 27 is abnormal depending on whether or not the sensor output difference ⁇ V before and after the switching is within a predetermined normal range.
- the DC resistance value (internal resistance value) of the oxygen sensor 21 is calculated based on the sensor output difference ⁇ V before and after switching. Thereafter, at the time t4 when the fuel cut is completed and the abnormality diagnosis permission flag is reset to OFF, the constant current I3 is passed between the sensor electrodes to change the output characteristics of the oxygen sensor 21, and this constant current is being supplied (that is, While the output characteristics of the oxygen sensor 21 are being changed), an output voltage fluctuation (output voltage drop or output voltage rise) is obtained from the constant current value I3 and the DC resistance value at that time, and this output voltage fluctuation is used. The output of the oxygen sensor 21 is corrected.
- the correction of the output of the oxygen sensor 21 is prohibited. This prevents the output of the oxygen sensor 21 from being corrected based on the sensor output difference ⁇ V that is out of the normal range due to an abnormality in the constant current circuit 27.
- the routine of FIG. 20 executed in the sixth embodiment is obtained by adding the processes of steps 708a and 708b after the process of step 708 of the routine of FIG. 16 described in the third embodiment. This processing is the same as in FIG.
- the constant current circuit 27 is controlled so that the constant current I1 flows between the sensor electrodes. Then, after detecting the output of the oxygen sensor 21 when the constant current I1 flows between the sensor electrodes as the sensor output V1 before switching, the constant current circuit 27 is controlled so that the constant current I2 flows between the sensor electrodes. The output of the oxygen sensor 21 when a constant current I2 is passed between the sensor electrodes is detected as the sensor output V2 after switching (steps 701 to 705).
- step 708b the above-described sensor output correction routine of FIG. 11 is executed, so that the constant current value and the oxygen sensor at that time are being supplied during constant current supply (that is, while the output characteristics of the oxygen sensor 21 are being changed).
- 21 is used to obtain an output voltage fluctuation (output voltage drop or output voltage rise) due to the internal resistance of the oxygen sensor 21 when supplying a constant current using the DC resistance value (internal resistance value) of 21. Used to correct the sensor output (the output of the oxygen sensor 21).
- step 707 determines that the sensor output difference ⁇ V before and after switching is not within the normal range (that is, out of the normal range)
- the process proceeds to step 709 and the constant current circuit 27 is abnormal. It is determined that there is a failure (for example, a failure), and the correction of the output of the oxygen sensor 21 is prohibited by terminating this routine without executing the processing of steps 708a and 708b. This function serves as a prohibited part.
- whether or not the constant current circuit 27 is abnormal is determined based on whether or not the difference ⁇ V in the output of the oxygen sensor 21 before and after switching of the current value flowing between the sensor electrodes is within the normal range,
- correction of the output of the oxygen sensor 21 is prohibited, so that the sensor output difference ⁇ V (abnormal value) deviated from the normal range due to an abnormality in the constant current circuit 27. It is possible to prevent the output of the oxygen sensor 21 from being corrected based on the above.
- the sensor output correction routine of FIG. 11 is executed in step 708b of the routine of FIG. 20.
- the present invention is not limited to this, and the target voltage correction routine of FIG. 12 is executed in step 708b. You may do it.
- step 707 if it is determined in step 707 that the sensor output difference ⁇ V before and after switching is within the normal range, the process proceeds to step 708, and after determining that there is no abnormality (normal) in the constant current circuit 27, the process proceeds to step 708a. Then, the DC resistance value (internal resistance value) of the oxygen sensor 21 is calculated from the sensor output difference ⁇ V before and after switching. Thereafter, the process proceeds to step 708b, and by executing the above-described target voltage correction routine of FIG. 12, the constant current value and the oxygen sensor at that time during the constant current supply (that is, during the change of the output characteristics of the oxygen sensor 21).
- step 707 determines that the sensor output difference ⁇ V before and after the switching is not within the normal range (that is, outside the normal range)
- the process proceeds to step 709 and the constant current circuit 27 is abnormal (for example, it is determined that there is a failure, etc., and the routine is terminated without executing the processing of steps 708a and 708b, thereby prohibiting the correction of the target voltage of the sub F / B control.
- the target voltage of the sub F / B control from being corrected based on the sensor output difference ⁇ V (abnormal value) that is out of the normal range due to the abnormality of the constant current circuit 27. it can.
- the constant current depends on whether or not the difference between the sensor outputs before and after switching (the difference between the sensor output V1 before switching and the sensor output V2 after switching) is within a predetermined normal range.
- the determination method of the presence / absence of abnormality is not limited to this, and may be changed as appropriate.
- the ratio of sensor output before and after switching (sensor output before switching) Whether or not there is an abnormality in the constant current circuit 27 may be determined based on whether or not the ratio of V1 to the sensor output V2 after switching is within a predetermined normal range.
- the constant current I1 before switching is set to 0 mA.
- the present invention is not limited to this, and the constant current before switching is set.
- I1 may be set to a predetermined value other than 0 mA.
- the constant current I2 after switching may be set to 0 mA, or may be set to a predetermined value other than 0 mA.
- the present invention is not limited to this, and it may be determined that the current switching permission condition (or abnormality diagnosis execution condition) is satisfied when the output of the oxygen sensor 21 is stable on the rich side. It may be determined that the current switching permission condition (or abnormality diagnosis execution condition) is satisfied during the fuel increase control for increasing the fuel injection amount.
- the current switching permission condition or abnormality diagnosis execution condition
- the current switching permission condition is satisfied during the fuel increase control for increasing the fuel injection amount.
- fuel increase control since rich gas flows into the exhaust pipe 17 and the exhaust pipe 17 becomes rich, it is determined that the current switching permission condition (or abnormality diagnosis execution condition) is satisfied during the fuel increase control. In this way, when the output of the oxygen sensor 21 becomes stable on the rich side during the fuel increase control, the value of the output voltage fluctuation information can be calculated by switching the current value flowing between the sensor electrodes.
- the current value flowing between the sensor electrodes is switched to calculate output voltage fluctuation information (or output).
- the present invention is not limited to this.
- the sensor electrode in response to a change request for increasing the rich response of the oxygen sensor 21 or a change request for increasing the lean response, the sensor electrode When the current value flowing between them is switched, the output voltage fluctuation information may be calculated (or the abnormality diagnosis is performed by calculating the output voltage fluctuation information).
- the constant current circuit 27 is connected to the atmosphere side electrode layer 34 of the oxygen sensor 21 (sensor element 31).
- the present invention is not limited to this.
- the oxygen sensor 21 The constant current circuit 27 may be connected to the exhaust-side electrode layer 33 of the sensor element 31).
- the constant current circuit 27 may be connected to both the exhaust side electrode layer 33 and the atmosphere side electrode layer 34.
- the present invention is applied to a system using the oxygen sensor 21 having the sensor element 31 having a cup-type structure.
- the present invention is not limited to this.
- a sensor element having a stacked structure type is used. You may apply this invention to the system using the oxygen sensor which has.
- the present invention is not limited to an oxygen sensor.
- an oxygen sensor such as an air-fuel ratio sensor that outputs a linear air-fuel ratio signal corresponding to an air-fuel ratio, an HC sensor that detects HC concentration, or an NO X sensor that detects NO X concentration.
- the present invention may be applied to this gas sensor. Further, the present invention may be applied to gas sensors other than those for engines.
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Abstract
Description
[センサ応答性制御ルーチン]
図8に示すセンサ応答性制御ルーチンは、ECU25の電源オン期間中に所定周期で繰り返し実行される。本ルーチンでは、ステップ101~103で、酸素センサ21の検出応答性を変更するための変更要求の有無を判定し、ステップ104~107で、変更要求の判定結果に基づいて定電流制御を実施して、酸素センサ21の検出応答性を変更する。
(2)エンジン11の油温(潤滑油の温度)が所定温度以下であること
(3)燃料経路内の燃料温度が所定温度以下であること
このステップ101で、エンジン11が冷間状態にあると判定された場合には、リッチ応答性(リッチ変化時の検出応答性)を高める変更要求が有ると判定する。この場合、ステップ104に進み、リッチ応答性を高める変更要求に基づいて定電流Icsの供給を制御する。具体的には、定電流回路27の定電流として「正の定電流Ics」を設定する。このとき、マイクロコンピュータ26により定電流回路27が制御され、排気側電極層33から大気側電極層34に酸素が供給される向きで定電流Ics(正の定電流Ics)が流れることとなる。これにより、エンジン11が冷間状態にある場合において酸素センサ21のリッチ応答性が高められる。尚、定電流量は予め定められた所定値であると良い。
(5)気筒内での燃焼圧が所定値以上であること
(6)アクセル開度が所定値以上であること
このステップ102で、エンジン11が高負荷運転状態になっていると判定された場合には、リーン応答性(リーン変化時の検出応答性)を高める変更要求が有ると判定する。この場合、ステップ105に進み、リーン応答性を高める変更要求に基づいて定電流Icsの供給を制御する。具体的には、定電流回路27の定電流として「負の定電流Ics」を設定する。このとき、マイクロコンピュータ26により定電流回路27が制御され、大気側電極層34から排気側電極層33に酸素が供給される向きで定電流Ics(負の定電流Ics)が流れることとなる。これにより、エンジン11が高負荷運転状態になっている場合において酸素センサ21のリーン応答性が高められる。尚、定電流量は予め定められた所定値であると良い。
[電流切換許可判定ルーチン]
図9に示す電流切換許可判定ルーチンは、ECU25の電源オン期間中に所定周期で繰り返し実行され、判定部としての役割を果たす。本ルーチンが起動されると、ステップ201~203で、電流切換許可条件が成立しているか否かを判定する。
[直流抵抗値演算ルーチン]
図10に示す直流抵抗値演算ルーチンは、ECU25の電源オン期間中に所定周期で繰り返し実行され、出力電圧変動情報演算部としての役割を果たす。本ルーチンが起動されると、まず、ステップ301で、電流切換許可フラグがオン(許可状態)であるか否かによって、電流切換許可条件が成立しているか否かを判定する。
[センサ出力補正ルーチン]
図11に示すセンサ出力補正ルーチンは、ECU25の電源オン期間中に所定周期で繰り返し実行され、センサ出力補正部としての役割を果たす。本ルーチンが起動されると、まず、ステップ401で、センサ電極間に定電流を流す定電流供給中(つまり酸素センサ21の出力特性の変更中)であるか否かを判定し、定電流供給中であると判定された場合には、ステップ402に進み、現在の定電流値と酸素センサ21の直流抵抗値(内部抵抗値)とを用いて定電流供給時の酸素センサ21の内部抵抗による出力電圧変動分(出力電圧降下分又は出力電圧上昇分)を次式により求める。
この際、例えば、酸素センサ21の出力電圧の降下方向に定電流を流した場合の出力電圧変動分(つまり出力電圧降下分)を負の値とし、酸素センサ21の出力電圧の上昇方向に定電流を流した場合の出力電圧変動分(つまり出力電圧上昇分)を正の値とする。
ECU25は、この補正後のセンサ出力(酸素センサ21の出力)を用いてサブF/B制御を行う。
この際、例えば、酸素センサ21の出力電圧の降下方向に定電流を流した場合の出力電圧変動分(つまり出力電圧降下分)を負の値とし、酸素センサ21の出力電圧の上昇方向に定電流を流した場合の出力電圧変動分(つまり出力電圧上昇分)を正の値とする。
ECU25は、この補正後の目標電圧を用いてサブF/B制御を行う。
[異常診断許可判定ルーチン]
図15に示す異常診断許可判定ルーチンは、ECU25の電源オン期間中に所定周期で繰り返し実行され、判定部としての役割を果たす。ステップ601~603で、異常診断実行条件(図9のルーチンのステップ201~203で説明した電流切換許可条件と同じ条件)が成立しているか否かを判定する。
[異常診断ルーチン]
図16に示す異常診断ルーチンは、ECU25の電源オン期間中に所定周期で繰り返し実行され、出力電圧変動情報演算部及び異常診断部としての役割を果たす。まず、ステップ701で、異常診断許可フラグがオン(許可状態)であるか否かによって、異常診断実行条件が成立しているか否かを判定する。
この後、ステップ707に進み、切り換え前後のセンサ出力差ΔVが所定の正常範囲内であるか否かを判定する。この正常範囲は、例えば、切り換え前後の定電流I1,I2等に基づいて設定されている。
この後、ステップ708bに進み、前述した図11のセンサ出力補正ルーチンを実行することで、定電流供給中(つまり酸素センサ21の出力特性の変更中)に、そのときの定電流値と酸素センサ21の直流抵抗値(内部抵抗値)とを用いて定電流供給時の酸素センサ21の内部抵抗による出力電圧変動分(出力電圧降下分又は出力電圧上昇分)を求め、この出力電圧変動分を用いてセンサ出力(酸素センサ21の出力)を補正する。
Claims (15)
- 一対のセンサ電極(33,34)間に固体電解質体(32)が配置されたセンサ素子(31)により被検出ガスに含まれる所定成分の濃度を検出するガスセンサ(21)を備えたガスセンサ制御装置において、
前記センサ電極(33,34)間に定電流を流して前記ガスセンサ(21)の出力特性を変更する定電流供給部(27)と、
前記センサ電極(33,34)間に流れる電流値が切り換わったときに、その切り換え前後の前記ガスセンサ(21)の出力に基づいて、前記センサ電極(33,34)間に前記定電流を流す定電流供給時の前記ガスセンサ(21)の出力電圧変動分又はこれと相関関係を有する情報(以下これらを「出力電圧変動情報」と総称する)を演算する出力電圧変動情報演算部(25)と
を備えていることを特徴とするガスセンサ制御装置。 - 所定の電流切換許可条件が成立しているか否かを判定する判定部(25)を備え、
前記出力電圧変動情報演算部(25)は、前記判定部(25)により前記電流切換許可条件が成立していると判定されたときに前記センサ電極(33,34)間に流れる電流値を切り換えて前記出力電圧変動情報の演算を実行することを特徴とする請求項1に記載のガスセンサ制御装置。 - 前記ガスセンサ(21)は、内燃機関(11)の排出ガスの空燃比のリッチ/リーンを検出するセンサであることを特徴とする請求項2に記載のガスセンサ制御装置。
- 前記判定部(25)は、前記ガスセンサ(21)の出力がリッチ側又はリーン側で安定しているときに前記電流切換許可条件が成立していると判定することを特徴とする請求項3に記載のガスセンサ制御装置。
- 前記判定部(25)は、前記内燃機関(11)の燃料噴射を停止する燃料カット中に前記電流切換許可条件が成立していると判定することを特徴とする請求項4に記載のガスセンサ制御装置。
- 前記判定部(25)は、前記内燃機関(11)の停止後に前記電流切換許可条件が成立していると判定することを特徴とする請求項4又は5に記載のガスセンサ制御装置。
- 前記判定部(25)は、前記内燃機関(11)の燃料噴射量を増量する燃料増量制御中に前記電流切換許可条件が成立していると判定することを特徴とする請求項4乃至6のいずれかに記載のガスセンサ制御装置。
- 前記出力電圧変動情報演算部(25)は、前記センサ電極(33,34)間に流れる電流値を切り換える際に、その切り換え前後の電流値のうちの一方を0にすることを特徴とする請求項1乃至7のいずれかに記載のガスセンサ制御装置。
- 前記出力電圧変動情報に基づいて前記定電流供給部(27)の異常の有無を判定する異常診断を行う異常診断部(25)を備えていることを特徴とする請求項1乃至8のいずれかに記載のガスセンサ制御装置。
- 請求項1乃至9のいずれかに記載のガスセンサ制御装置と、前記ガスセンサ(21)の出力に基づいて内燃機関(11)の制御を実行する制御部(25)とを備えた内燃機関の制御装置において、
前記定電流供給時に前記出力電圧変動情報に基づいて前記ガスセンサ(21)の出力を補正するセンサ出力補正部(25)を備え、
前記制御部(25)は、前記センサ出力補正部(25)による補正後の前記ガスセンサ(21)の出力を用いて前記制御を行うことを特徴とする内燃機関の制御装置。 - 前記出力電圧変動情報演算部(25)は、前記出力電圧変動情報として前記ガスセンサ(21)の直流抵抗値を演算し、
前記センサ出力補正部(25)は、前記定電流供給時の定電流値と前記直流抵抗値から前記出力電圧変動分を求め、該出力電圧変動分を用いて前記ガスセンサ(21)の出力を補正することを特徴とする請求項10に記載の内燃機関の制御装置。 - 前記出力電圧変動情報に基づいて前記定電流供給部(27)の異常の有無を判定する異常診断部(25)と、
前記異常診断部(25)により前記定電流供給部(27)の異常有りと判定された場合に、前記センサ出力補正部(25)による前記ガスセンサ(21)の出力の補正を禁止する禁止部(25)と
を備えていることを特徴とする請求項10又は11に記載の内燃機関の制御装置。 - 請求項1乃至9のいずれかに記載のガスセンサ制御装置と、前記ガスセンサ(21)の出力に基づいて内燃機関(11)の空燃比制御を実行する制御部(25)とを備えた内燃機関の制御装置において、
前記定電流供給時に前記出力電圧変動情報に基づいて前記空燃比制御の目標値を補正する目標値補正部(25)を備え、
前記制御部(25)は、前記目標値補正部(25)による補正後の前記目標値を用いて前記空燃比制御を行うことを特徴とする内燃機関の制御装置。 - 前記出力電圧変動情報演算部(25)は、前記出力電圧変動情報として前記ガスセンサ(21)の直流抵抗値を演算し、
前記目標値補正部(25)は、前記定電流供給時の定電流値と前記直流抵抗値から前記出力電圧変動分を求め、該出力電圧変動分を用いて前記目標値を補正することを特徴とする請求項13に記載の内燃機関の制御装置。 - 前記出力電圧変動情報に基づいて前記定電流供給部(27)の異常の有無を判定する異常診断部(25)と、
前記異常診断部(25)により前記定電流供給部(27)の異常有りと判定された場合に、前記目標値補正部(25)による前記目標値の補正を禁止する禁止部(25)と
を備えていることを特徴とする請求項13又は14に記載の内燃機関の制御装置。
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- 2013-01-22 US US14/376,243 patent/US20150025778A1/en not_active Abandoned
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WO2014196131A1 (ja) * | 2013-06-04 | 2014-12-11 | 株式会社デンソー | ガスセンサ制御装置 |
JP2014235104A (ja) * | 2013-06-04 | 2014-12-15 | 株式会社デンソー | ガスセンサ制御装置 |
WO2015019583A1 (ja) * | 2013-08-09 | 2015-02-12 | 株式会社デンソー | ガスセンサ制御装置 |
JP2015034803A (ja) * | 2013-08-09 | 2015-02-19 | 株式会社デンソー | ガスセンサ制御装置 |
US20160201540A1 (en) * | 2013-08-09 | 2016-07-14 | Denso Corporation | Gas sensor control device |
US9845719B2 (en) | 2013-08-09 | 2017-12-19 | Denso Corporation | Gas sensor control device |
Also Published As
Publication number | Publication date |
---|---|
JP5907345B2 (ja) | 2016-04-26 |
JP2013178227A (ja) | 2013-09-09 |
US20150025778A1 (en) | 2015-01-22 |
DE112013000829T5 (de) | 2014-12-04 |
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