CN109751107A - Sensing system - Google Patents

Sensing system Download PDF

Info

Publication number
CN109751107A
CN109751107A CN201811311725.7A CN201811311725A CN109751107A CN 109751107 A CN109751107 A CN 109751107A CN 201811311725 A CN201811311725 A CN 201811311725A CN 109751107 A CN109751107 A CN 109751107A
Authority
CN
China
Prior art keywords
temperature
exhaust
sensor
sensor element
target
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN201811311725.7A
Other languages
Chinese (zh)
Inventor
森广锦司
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toyota Motor Corp
Original Assignee
Toyota Motor Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Toyota Motor Corp filed Critical Toyota Motor Corp
Publication of CN109751107A publication Critical patent/CN109751107A/en
Pending legal-status Critical Current

Links

Classifications

    • 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
    • F01N11/00—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity
    • 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
    • F01N11/00—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity
    • F01N11/002—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity the diagnostic devices measuring or estimating temperature or pressure in, or downstream of the exhaust apparatus
    • F01N11/005—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity the diagnostic devices measuring or estimating temperature or pressure in, or downstream of the exhaust apparatus the temperature or pressure being estimated, e.g. by means of a theoretical model
    • 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
    • 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
    • F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
    • F01N2560/06—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being a temperature sensor
    • 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
    • F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
    • F01N2560/20—Sensor having heating means
    • 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
    • F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
    • F01N2900/06—Parameters used for exhaust control or diagnosing
    • F01N2900/14—Parameters used for exhaust control or diagnosing said parameters being related to the exhaust gas
    • F01N2900/1404—Exhaust gas temperature
    • 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
    • F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
    • F01N2900/06—Parameters used for exhaust control or diagnosing
    • F01N2900/14—Parameters used for exhaust control or diagnosing said parameters being related to the exhaust gas
    • F01N2900/1411—Exhaust gas flow rate, e.g. mass flow rate or volumetric flow rate
    • 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
    • F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
    • F01N2900/06—Parameters used for exhaust control or diagnosing
    • F01N2900/16—Parameters used for exhaust control or diagnosing said parameters being related to the exhaust apparatus, e.g. particulate filter or catalyst
    • F01N2900/1602—Temperature of exhaust gas apparatus
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/40—Engine management systems

Abstract

This disclosure relates to a kind of sensing system.The sensing system has: temperature prediction portion, and prediction is provided with the temperature of the exhaust of the internal combustion engine at the position of exhaust sensor；And control unit, it is to control heater so that the temperature of sensor element approaches the control unit for being contained in the target temperature of preset range, in the case where predicted temperature is higher than fiducial temperature, comparing target temperature in the range lower than fiducial temperature when predicted temperature Gao Shiyu predicted temperature is low reduces, in the case where predicted temperature is lower than fiducial temperature, comparing target temperature in the range higher than fiducial temperature when predicted temperature Gao Shiyu predicted temperature is low is reduced.

Description

Sensing system
Technical field
The present invention relates to sensing systems.
Background technique
In the sensor of the ingredient included in the exhaust of detection internal combustion engine, exists to have sensor element is added The sensor of the heater of heat.For example, even, identical air-fuel ratio, detected value also can root for air-fuel ratio sensor It changes according to the temperature of sensor element, so by control heater so that the temperature of sensor element is in predetermined model In enclosing, to maintain the detection accuracy of air-fuel ratio.Additionally, it is known that have in order to change to specific exhaust gas composition (such as NOx, HC, CO detection sensitivity) and the technology for adjusting the temperature of sensor element within a predetermined range (for example, referring to patent document 1). In the technology described in patent document 1, it when the operating being easy to produce in high load capacity etc. under dilute air-fuel ratio of NOx, improves Sensor element temperature is so that the reactivity to NOx is got higher, when being easy to produce under the dense air-fuel ratio of HC, CO in underload etc. Operating when, reduce sensor element temperature so that the reactivity to HC, CO is got higher.
Existing technical literature
Patent document
Patent document 1: Japanese Unexamined Patent Publication 2003-314350 bulletin
Summary of the invention
Problems to be solved by the invention
Even if utilizing heater so that the temperature of sensor element is predetermined to maintain the detection accuracy of sensor Mode in range has adjusted the temperature of sensor element, such as in the case that internal combustion engine operates under high loads, because of exhaust Temperature it is high so even if not heated using heater, sensor element also receives heat from exhaust and temperature rises, so When further increasing the temperature of sensor element using heater, the temperature of sensor element is possible to become excessively high and deviate Preset range.That is, the detection accuracy of sensor is likely to decrease.
The present invention is the invention made in view of problem as described above, and its object is to by the temperature of sensor element It maintains in suitable range.
Technical teaching for solving the problem was
Technical solution of the present invention first is that a kind of sensing system, the sensing system have: exhaust sensor, setting In the exhaust channel of internal combustion engine, the heater for having sensor element and being heated to the sensor element；Temperature prediction Portion, prediction are provided with the temperature of the exhaust of the internal combustion engine at the position of the exhaust sensor；And control unit, it is control The heater so that the sensor element temperature close to be contained in preset range target temperature control unit, by Temperature, that is, predicted temperature of the exhaust of temperature prediction portion prediction feelings higher than the fiducial temperature for being contained in the preset range Under condition, make the target temperature in the range lower than the fiducial temperature when the predicted temperature is high with the predicted temperature Compared to reducing when low, in the case where the predicted temperature is lower than the fiducial temperature, make the target temperature than the base It is reduced compared with when the predicted temperature is low in the high range of quasi- temperature when the predicted temperature is high.
Exhaust sensor is that can adjust the sensor of the temperature of sensor element by controlling the energization to heater. Even if receiving heat not by heater from exhaust by sensor element, being seized heat by exhaust, the temperature of sensor element can also It can change.Here, although it is contemplated that feedback control is carried out to heater, so that the temperature of sensor element is close to target Temperature, but when controlling after the temperature in sensor element actually changes to the energization of heater, relative to sensing The temperature change of device element, the power control delay of heater, the temperature of sensor element may deviate from preset range.This Outside, preset range is the temperature range of the detection accuracy of exhaust sensor within the allowable range, is the work based on sensor element The range of property temperature range.It, can also be in addition, preset range is also possible to the range equal with the field of activity of sensor element Be in order to there are ampleness so that the temperature of sensor element does not deviate by the range of field of activity and specific activity narrow range.Sensing The fiducial temperature of the temperature of device element can be exhaust sensor detection accuracy become highest when temperature or be also possible to The central temperature of temperature range when the detection accuracy of exhaust sensor is as highest.In addition, fiducial temperature is also possible to make a reservation for The central temperature of range.
The temperature of exhaust around exhaust sensor can be passed according to the operating condition of internal combustion engine and from internal combustion engine to exhaust Thermal capacity in exhaust system between sensor etc. is predicted.That is, the temperature for the exhaust flowed out from internal combustion engine and the fortune of internal combustion engine It is related to turn state, even if so can also predict it before gas actually is discharged from internal combustion engine.In addition, from internal combustion engine When the gas of discharge circulates in exhaust system by exhaust system seize heat and temperature reduce.Its temperature reductions also can be preparatory It is predicted.Therefore, even if before the exhaust of internal combustion engine reaches around exhaust sensor, it can also predict that the exhaust reaches exhaust Temperature when around sensor.Also, if the temperature based on the exhaust predicted occurs that the temperature of sensor element in advance Variation is then able to suppress the temperature change delay this case of temperature adjustment relative to exhaust of sensor element.That is, predicting Exhaust temperature it is higher than fiducial temperature in the case where, so that the target temperature of sensor element is reduced lower than fiducial temperature, by Even if the temperature of this exhaust is got higher, the temperature of sensor element can be also reduced in advance.In addition, the temperature ratio of the exhaust in prediction In the case that fiducial temperature is low, the target temperature of sensor element is made to improve higher than fiducial temperature, even if the thus temperature of exhaust Degree is lower, and can also improve the temperature of sensor element in advance.In turn, and pre- so that when the temperature of the exhaust of prediction is higher The temperature of the exhaust of survey is compared when lower, reduces the target temperature of sensor element, even if thus the temperature of exhaust is got higher, The temperature of sensor element can be reduced in advance according to the temperature of exhaust, in addition, even if the temperature of exhaust is lower, it also being capable of basis The temperature of exhaust improves the temperature of sensor element in advance.In addition, by making target temperature change within a predetermined range, energy Enough target temperature is inhibited to become excessively high, become too low.Therefore, the temperature of sensor element can be maintained suitable range It is interior.
In addition, the sensing system is also equipped with volume forecasting portion, the fortune of the volume forecasting portion based on the internal combustion engine The flow of the exhaust for the internal combustion engine at position for turning state to predict to be provided with the exhaust sensor, the control unit, When the flow for the exhaust predicted by the volume forecasting portion is more, when few with the flow for the exhaust predicted by the volume forecasting portion It is bigger compared to the bias that the target temperature can be made to deviate the fiducial temperature.
In the same manner as the temperature of the exhaust around exhaust sensor, the flow and internal combustion engine of the exhaust around exhaust sensor Operating condition etc. it is related, so can be predicted according to operating condition of internal combustion engine etc..That is, even if internal combustion engine row Before gas reaches exhaust sensor, the flow when exhaust reaches around exhaust sensor can be also predicted.Here, in the temperature of exhaust In the case that degree is higher than the temperature of sensor element, the flow of exhaust is more, then the faster rising of the temperature of sensor element.Separately Outside, in the case where the temperature of exhaust is lower than the temperature of sensor element, the flow of exhaust is more, then the temperature of sensor element Faster reduction.That is, when the flow of exhaust is more, compared with when the flow of exhaust is less, the temperature change of sensor element Speed becomes faster.Even if the temperature for the sensor element assuming that the temperature of exhaust is identical and being finally reached is identical, reach this most Time until whole temperature is also different according to the flow of exhaust.In contrast, if making target temperature according to the flow of exhaust Degree changes, then can not only be according to the temperature being finally reached, also can be according to the speed of the temperature change of sensor element To set target temperature.Even if in this case, being also able to suppress target temperature by setting target temperature within a predetermined range Become excessively high, become too low.In addition, in the case where the bias for further increasing target temperature deviation fiducial temperature is this kind of, It shows as further decreasing target temperature when target temperature is lower than fiducial temperature, be showed when target temperature is higher than fiducial temperature To further increase target temperature.
In addition, the sensing system is also equipped with accelerator opening sensor, the temperature prediction portion can be based on by institute The accelerator opening that accelerator opening sensor detects is stated to predict the temperature of the exhaust.
The operating condition of internal combustion engine changes according to accelerator opening, so the operating of accelerator opening and internal combustion engine State is related.Therefore, accelerator opening is related with the temperature of exhaust flowed out from internal combustion engine, so accelerator opening can be based on To predict the temperature for the exhaust flowed out from internal combustion engine.The exhaust reach exhaust sensor around when temperature also can as it is above-mentioned that Sample is predicted.Therefore, the temperature of the exhaust around exhaust sensor can be easily predicted based on accelerator opening.
In addition, the sensing system is also equipped with accelerator opening sensor, the volume forecasting portion can be based on by institute The accelerator opening that accelerator opening sensor detects is stated to predict the flow of the exhaust.
The flow of exhaust around exhaust sensor also changes according to accelerator opening, so can be based on acceleration Device aperture easily predicts the flow of the exhaust around exhaust sensor.
In addition, the upper limit can be arranged to pace of change when making the target temperature change in the control unit.
The upper limit is set by the pace of change to target temperature, the temperature for being able to suppress exhaust sensor mutates, institute With the deviation for being able to suppress the damage of exhaust sensor, being able to suppress generation detected value.
In addition, technical solution of the present invention first is that a kind of sensing system, the sensing system have: exhaust sensing Device is set to the exhaust channel of internal combustion engine, the heater for having sensor element and being heated to the sensor element；Add Fast device jaw opening sensor；And control unit, the heater is controlled so that the temperature of the sensor element is approached and is contained in The target temperature of preset range, the control unit are contained in institute in the temperature ratio for making the exhaust around the exhaust sensor In the case where stating accelerator opening as the fiducial temperature height of preset range, make the target temperature than the fiducial temperature It is reduced compared with the accelerator opening hour in low range when the accelerator opening is big, the exhaust is sensed In the case where the temperature of exhaust around device such accelerator opening lower than the fiducial temperature, make the target temperature than It is reduced compared with the accelerator opening hour in the high range of the fiducial temperature when the accelerator opening is big.
As described above, accelerator opening is related with the temperature of exhaust around the exhaust sensor in future, so even if not The temperature for predicting the exhaust around the exhaust sensor in future, also can be based on the direct setting sensor element of accelerator opening Target temperature.
Invention effect
In accordance with the invention it is possible to the temperature of sensor element be maintained in suitable range.
Detailed description of the invention
Fig. 1 is the figure for showing the outline structure of internal combustion engine and its gas handling system that embodiment is related to and exhaust system.
Fig. 2 is the cross-sectional view of air-fuel ratio sensor.
Fig. 3 be show the temperature ET and sensor element of the exhaust around the air-fuel ratio sensor of prediction target temperature it is inclined The figure of the relationship of offset (target offset amount) from fiducial temperature.
Fig. 4 is the figure for correcting target offset amount shown in Fig. 3.
Fig. 5 is to show hypothesis to make pushing away for various values of the target temperature of sensor element with fiducial temperature in the case where constant The time diagram of shifting.
Fig. 6 is to show to implement pushing away for the various values in the case that the sensor element impedance that embodiment 1 is related to controls The time diagram of shifting.
Fig. 7 is the flow chart for showing the process of the duty ratio in the element impedance control that setting embodiment 1 is related to.
Fig. 8 is the duty ratio shown in the element impedance control that setting embodiment 1 is related to and the flow for not considering exhaust In the case where process flow chart.
Fig. 9 is the flow chart for showing the process of the duty ratio in the element impedance control that setting embodiment 2 is related to.
Specific embodiment
Embodiment for carrying out the present invention is illustrated referring to the drawings.But, in present embodiment It for the size of the structural elements of middle record, material, shape, its relative configuration etc., is recorded as long as no special, just not purport The scope of the present invention is only being defined in above-mentioned record.
(embodiment 1)
Fig. 1 is the figure for showing the outline structure of internal combustion engine 1 of the present embodiment and its gas handling system and exhaust system. Internal combustion engine 1 is the petrol engine for being equipped on vehicle 50.In addition, present embodiment can also be suitable for diesel engine.Exhaust Access 2 is connected to internal combustion engine 1.Exhaust channel 2 is provided with catalyst 3, but the not required structure of the catalyst 3.
In turn, in the air-fuel ratio for the exhaust for being provided with detection inflow catalyst 3 than the exhaust channel 2 by the upstream of catalyst 3 Air-fuel ratio sensor 11 and detection inflow catalyst 3 exhaust temperature temperature sensor 12.The air-fuel ratio sensor 11 It is the lambda sensor of such as carrying current formula, is generated and the generally proportionate output of air-fuel ratio on wide air/fuel region.This Outside, air-fuel ratio sensor 11 is not limited to the lambda sensor of carrying current formula, is also possible to such as electromotive force formula (concentration cell formula) Lambda sensor.In addition, in the present embodiment, air-fuel ratio sensor 11 is equivalent to the exhaust sensor in the present invention.
Fig. 2 is the cross-sectional view of air-fuel ratio sensor 11.Air-fuel ratio sensor 11 includes the air-fuel ratio for carrying out and being vented (can also Think oxygen concentration) the sensor element 11A exported accordingly and the heater 11B that sensor element 11A is heated.It passes Sensor component 11A includes solid electrolyte layer 101, the room A lateral electrode 102, the room B lateral electrode 103, diffusion law speed floor 104.Solid electricity Solution matter floor 101 separates the room A being communicated with the atmosphere and the room B being connected to the inside of exhaust channel 2.Solid electrolyte layer 101 by Zirconium oxide (Zr2O3) etc. cellular insulant materials constitute.The room the A side wall surface of solid electrolyte layer 101 is provided with the A formed by platinum Room lateral electrode 102 is provided with the room the B lateral electrode 103 formed by platinum in the room the B side wall surface of solid electrolyte layer 101.The room B side electricity The surface of pole 103 is covered by diffusion law speed layer 104, and a part for the exhaust flowed in exhaust channel 2 passes through diffusion law speed layer 104 inside and contacted with the room B lateral electrode 103.In addition, state of the heater 11B in the room A side to be clamped by insulating substrate 105 Setting.
In the air-fuel ratio sensor 11 of such structure, apply when between the room A lateral electrode 102 and the room B lateral electrode 103 When predetermined voltage, by the application of the voltage, electric current corresponding with the oxygen concentration in exhaust flows in air-fuel ratio sensor 11. The electric current is related with air-fuel ratio, so air-fuel ratio sensor 11 detects air-fuel ratio based on the electric current.
In addition, being respectively arranged with the fuel of the spark plug 5 for generating electric spark and injection fuel in each cylinder of internal combustion engine 1 Injection valve 6.In addition, intake channel 7 is connected to internal combustion engine 1.Intake channel 7 is provided with air flow meter 23 and air throttle 8.It is empty Air-flow meter 23 is the sensor for detecting the inhaled air volume of internal combustion engine 1.The inhaled air volume of the adjustment internal combustion engine 1 of air throttle 8.
Also, it is provided with the ECU10 as electronic control unit together in internal combustion engine 1 as control device (control Device).It is stored with the program of control internal combustion engine 1, emission-control equipment etc. in ECU10, according to the program, ECU10 controls internal combustion engine 1, emission-control equipment etc..In ECU10, other than above-mentioned various sensors, it is also electrically connected with turn of output and internal combustion engine 1 The crankshaft position sensor 21 of fast corresponding signal exports signal corresponding with aperture (accelerator opening) of accelerator pedal The vehicle speed sensor 24 of accelerator opening sensor 22, output signal corresponding with the side line of vehicle 50, the output of each sensor It is worth to ECU10 and transmits.
Therefore, ECU10 will appreciate that the internal-combustion engine rotational speed of the detection based on crankshaft position sensor 21, be opened based on accelerator Spend the operating condition of the internal combustion engines 1 such as the engine load rate of detection of sensor 22.On the other hand, spark plug 5, fuel injection valve 6, air throttle 8 and heater 11B are connected to ECU10 via electrical wiring, and are controlled by the ECU10 them.That is, logical Cross ECU10 control ignition timing, fuel injection amount, fuel injection timing, throttle opening, heater 11B temperature.
ECU10 sets the mesh for internal combustion engine 1 based on the accelerator opening detected by accelerator opening sensor 22 Mark torque.In addition, first passing through experiment or simulation etc. in advance finds out the relationship of accelerator opening and target torque, and it is stored in ECU10. Also, ECU10 controls internal combustion engine 1, to realize the target torque (so that the torque of internal combustion engine 1 becomes target torque).By this The control of sample is known as torque-demand control.The torque-demand control be well known control, be execute air throttle 8 aperture control and Ignition timing control of spark plug 5 etc. is to realize the control of target torque.That is, calculating target section based on target torque Valve opening, and calculate and realized required for target torque on the basis of the inhaled air volume under the target throttle opening Ignition timing.That is, ignition timing is set as optimum igniting timing (MBT on the basis of above-mentioned inhaled air volume by presumption (Minimum Advance for Best Torque)) when the torque that can obtain, according to target torque relative to the presumption torque Ratio calculate the retardation (from the retardation of MBT) of ignition timing, execute aperture control and the spark plug 5 of air throttle 8 Ignition timing control, with the retardation that obtains above-mentioned calculated target throttle opening and ignition timing, (target ignition is just When), it is thus target torque by the direct torque of internal combustion engine 1.In addition, ECU10 is opened based on accelerator in torque-demand control Degree, the engine load rate of the internal-combustion engine rotational speed and future that calculate future.
In addition, ECU10 carries out feedback control to fuel injection amount or throttle opening, so that by air-fuel ratio sensor 11 The air-fuel ratio (detection air-fuel ratio) detected becomes target air-fuel ratio.The control is known as air-fuel ratio feedback control.
In addition, ECU10 in order to maintain the detection accuracy of air-fuel ratio sensor 11, controls heater 11B, so that The temperature of sensor element 11A is in preset range.When the temperature departure of the sensor element 11A preset range, air-fuel It can change than the detected value of sensor 11 and the correlation of actual air-fuel ratio, so the sky based on air-fuel ratio sensor 11 The detection accuracy of combustion ratio is lower.The preset range is the range of the active temperature of sensor element 11A (such as from 650 DEG C Range to 750 DEG C).In this case, the temperature of sensor element 11A can be by the impedance of sensor element 11A come table It is existing.That is, in the presence of when the temperature of sensor element 11A is got higher impedance become smaller this relationship.In the present embodiment, setting indicates The target impedance of target temperature, detection indicate the actual impedance of the actual temperature of sensor element 11A, and ECU10 is to heating The output of device 11B carries out feedback control, so that actual impedance is consistent with target impedance.The control is known as sensor element Impedance control.In addition, the element impedance control in present embodiment is a temperature controlled example of sensor element 11A, The temperature that can also implement sensor element 11A by other controls controls.
In sensor element impedance control, even if ECU10 receives heat from exhaust according to air-fuel ratio sensor 11, is vented Heat is seized, the temperature of the sensor element 11A of air-fuel ratio sensor 11 is also at the mode in preset range and sets target temperature (target impedance) carries out duty ratio control to heater 11B, so that the temperature of sensor element 11A is consistent with target temperature.
The temperature of sensor element 11A is adjusted by sensor element impedance control.But there are following situations: interior The temperature that combustion engine rate of load condensate gets higher and is vented can be got higher, due to receiving heat, the temperature of sensor element 11A from the exhaust of the high temperature It can rise.In this case, the temperature of sensor element 11A rises in which can be not dependent on sensor element impedance control, so The temperature of sensor element 11A is possible to become the upper limit for height than preset range.On the other hand, there are following situations: internal combustion engine The temperature that rate of load condensate is lower and is vented can be lower, since the exhaust of the low temperature seizes heat, the temperature of sensor element 11A can under Drop.In this case, it is controlled by sensor element impedance, the temperature of sensor element 11A rises, but is being seized by exhaust In the case that the amount of heat is more, the temperature of sensor element 11A is possible to become lower than the lower limit of preset range.
Then, ECU10 is pre-adjusted based on the temperature (predicted temperature) for the exhaust predicted around air-fuel ratio sensor 11 The temperature of sensor element 11A.That is, comparing sensor element by the temperature of the exhaust around air-fuel ratio sensor 11 in the future The temperature of 11A is low and in the case that the temperature of sensor element 11A is likely to decrease, actually make to pass in the low exhaust of the temperature Before the temperature of sensor component 11A reduces, the temperature of sensor element 11A is improved in advance.At this point, the target in element impedance control Temperature improves.On the other hand, pass through temperature of the temperature than sensor element 11A of the exhaust around air-fuel ratio sensor 11 in future Degree it is high and in the case that the temperature of sensor element 11A is possible to rising, actually make sensor first in the high exhaust of the temperature Before the temperature of part 11A rises, the temperature of sensor element 11A is reduced in advance.
The prediction of the temperature of exhaust around air-fuel ratio sensor 11 utilizes the internal combustion engine calculated in torque-demand controls Revolving speed and engine load rate carry out.The temperature of internal-combustion engine rotational speed and engine load rate and the gas being discharged from internal combustion engine 1 There are correlativities, find out the relationship so first passing through experiment or simulation etc. in advance and mapped and are stored in ECU10.Separately Outside, during circulation in exhaust channel 2 in the exhaust flowed out from internal combustion engine 1 until reaching air-fuel ratio sensor 11, row Heat possessed by gas sheds via the wall facing external of exhaust channel 2, so the temperature of exhaust reduces.The drop of the temperature of the exhaust Low amounts is influenced by the thermal capacity for the component that the exhaust system until from internal combustion engine 1 to air-fuel ratio sensor 11 has, institute The temperature of the exhaust around air-fuel ratio sensor 11 is calculated to consider these thermal capacity.
For example, being predicted based on the internal-combustion engine rotational speed and engine load rate that are calculated in torque-demand controls from internal combustion engine The temperature of the exhaust of 1 outflow, to the temperature predicted multiplied by pre-determined factor, thus, it is possible to predict that the exhaust reaches air-fuel ratio to pass Temperature when 11 surrounding of sensor.The pre-determined factor can also be set according to the flow for the exhaust flowed out from internal combustion engine 1.That is, row The flow of gas is fewer, then influenced by the thermal capacity of exhaust system it is bigger, so reach air-fuel ratio sensor 11 until row The temperature reductions of gas are bigger.In advance first pass through experiment or simulation etc. find out the relationship of the flow of exhaust and pre-determined factor and by its Mappingization and be stored in ECU10.In addition, there are correlativities with inhaled air volume for the flow of exhaust, so can also be based on suction Enter air capacity to obtain pre-determined factor.
In addition, for example in view of the thermal capacity of exhaust system be it is constant, first pass through experiment or simulation etc. in advance and find out internal combustion engine Relationship and mapped of revolving speed and engine load rate and the temperature of the exhaust around air-fuel ratio sensor 11 and be stored in ECU10.Alternatively, it is also possible to be, dissipating in the physical model or exhaust channel 2 by considering the heat dissipation in exhaust channel 2 The mapping of heat or calculating formula etc. find out the heat dissipation capacity in exhaust channel 2, based on the heat dissipation capacity and the row flowed out from internal combustion engine 1 The temperature of gas is come temperature when predicting that the exhaust reaches air-fuel ratio sensor 11.
Fig. 3 is the target for showing the temperature ET and sensor element 11A of the exhaust around the air-fuel ratio sensor 11 of prediction The figure of the relationship of the offset (target offset amount) of temperature departure fiducial temperature.The delivery temperature ET of horizontal axis is according to internal combustion engine 1 Operating condition prediction air-fuel ratio sensor 11 around exhaust temperature, based on torque-demand control used in accelerate Device aperture calculates.Fiducial temperature shown in Fig. 3 refers to the fiducial temperature of sensor element 11A, for example, 700 DEG C.The benchmark Temperature is the temperature as benchmark so that when the mode that the temperature of sensor element 11A is in preset range is controlled Degree.In addition, the detection accuracy that fiducial temperature is also possible to air-fuel ratio sensor 11 becomes highest temperature.Therefore, it is indicated by ET3 Delivery temperature ET indicate prediction air-fuel ratio sensor 11 around exhaust temperature and sensor element 11A fiducial temperature It is equal.
The target offset amount of the longitudinal axis in Fig. 3 indicates the deviation benchmark temperature when target temperature of setting sensor element 11A The offset of degree."+30 " in target offset amount indicate to keep the target temperature of sensor element 11A 30 DEG C higher than fiducial temperature, " 0 " indicates to keep the target temperature of sensor element 11A equal with fiducial temperature, and " -30 " indicate the target for making sensor element 11A Temperature reduces by 30 DEG C than fiducial temperature.
In the case where delivery temperature ET ratio ET3 is low, the delivery temperature ET around the air-fuel ratio sensor 11 of prediction can compare Fiducial temperature is low.In this case, when the low exhaust of temperature actually arrives in air-fuel ratio sensor 11, it is possible to have little time into Row the heating based on heater 11B and sensor element 11A temperature reduce.Therefore, air-fuel ratio sensor is being predicted 11 weeks The temperature for the exhaust enclosed becomes in the situation (predicting the situation that delivery temperature ET becomes lower than ET3) lower than fiducial temperature, in advance First improve the temperature of sensor element 11A.In this case, in the target for making the sensor element 11A in element impedance control Temperature improve it is higher than fiducial temperature in the state of carry out element impedance control.
In Fig. 3, delivery temperature ET be ET1 between ET2 in the case where, delivery temperature ET is smaller, makes target offset It measures bigger.That is, the delivery temperature ET of prediction is lower, then make target offset amount bigger, it is pre- thus according to the delivery temperature ET of prediction First improve the temperature of sensor element 11A.In addition, becoming target offset amount continuously according to delivery temperature ET in Fig. 3 Change, but can also be used as substitution, it is made periodically to change.
On the other hand, the upper limit of target offset amount is set as+30 DEG C.Therefore, the situation low in delivery temperature ET ratio ET1 Under, target offset amount is fixed to+30 DEG C.In addition, in the case where deviation occurs in the prediction of delivery temperature, sensor element The temperature of 11A may deviate from preset range, so making the upper limit of target offset amount, there are a degree of ampleness.That is, so that The target temperature for obtaining sensor element 11A becomes in the range narrower than preset range (such as 650 DEG C to 750 DEG C range) The mode of change sets the upper limit of target offset amount.But the upper limit of target offset amount can also increase to it is upper with preset range Limit (such as 750 DEG C) corresponding offset (such as+50 DEG C).In this way, adjusting the target of sensor element 11A within a predetermined range Temperature, so being able to suppress the temperature of the sensor element 11A when heater 11B heats sensor element 11A becomes It is excessively high and this case that can deviate preset range.ET1 is the sensor element when increasing target offset amount according to delivery temperature The temperature of 11A is possible to the upper limit value of the delivery temperature of the upper limit more than preset range.
In addition, even if delivery temperature ET ratio ET3 is low, when delivery temperature ET when ET2 is between ET3 target offset amount also by It is set as 0.Here, prediction delivery temperature ET close to fiducial temperature, so even if prediction delivery temperature ET than benchmark temperature Spend it is low in the case where, the amount of the heat seized from sensor element 11A is few, so in the range of the temperature, even if not making target Temperature changes, and the temperature of sensor element 11A is also the value close to fiducial temperature.Therefore, when delivery temperature ET ET2 extremely When between ET3, target offset amount is set as 0 without bringing it about variation.Thereby, it is possible to simplified controls.But it is also possible to Be, though delivery temperature ET in ET2 between ET3, also with delivery temperature ET when ET1 is between ET2 identical, delivery temperature The ET the low, keeps target offset amount bigger.Even if target temperature or target offset amount is not made to change, ET2 can be used as energy Enough temperature convergences by sensor element 11A is found out in the lower limit of the delivery temperature ET in preset range.
In the case where delivery temperature ET ratio ET3 high, the delivery temperature ET around the air-fuel ratio sensor 11 of prediction becomes It is higher than fiducial temperature.In this case, when the high exhaust of temperature actually arrives in air-fuel ratio sensor 11, it is possible to even if subtracting Lack the heating amount based on heater 11B and has little time cooling also to which the temperature of sensor element 11A rises.Therefore, it is predicting The temperature of exhaust around to air-fuel ratio sensor 11 becomes the situation higher than fiducial temperature, and (predicting delivery temperature ET becomes to compare The situation of ET3 high) under, the temperature of sensor element 11A is reduced in advance.In this case, make the biography in element impedance control The target temperature of sensor component 11A reduce it is lower than fiducial temperature in the state of carry out element impedance control.
In Fig. 3, in delivery temperature ET in the case where ET4 is between ET5, the delivery temperature ET the big, makes target offset It measures smaller.That is, the delivery temperature ET of prediction is higher, then make target offset amount smaller, it is pre- thus according to the delivery temperature ET of prediction First reduce the temperature of sensor element 11A.In addition, becoming target offset amount continuously according to delivery temperature ET in Fig. 3 Change, but can also be used as substitution, it is made periodically to change.
It on the other hand, is -30 DEG C by the lower limit set of target offset amount.Therefore, in the situation of delivery temperature ET ratio ET5 high Under, target offset amount is fixed to -30 DEG C.In addition, in the case where deviation occurs in the prediction of delivery temperature, sensor element The temperature of 11A may deviate from preset range, so making the lower limit of target offset amount, there are a degree of ampleness.That is, according to The mode for changing the target temperature of sensor element 11A in the range narrower than preset range is set under target offset amount Limit.But the lower limit of target offset amount also can reduce offset corresponding with the lower limit of preset range (such as 650 DEG C) (such as -50 DEG C).Temperature of the temperature that ET5 is sensor element 11A possibly lower than the lower limit of preset range.So, Due to adjusting the target temperature of sensor element 11A within a predetermined range, so being able to suppress the temperature meeting of sensor element 11A This case that become too low and deviate preset range.ET5 is the sensor member when reducing target offset amount according to delivery temperature Lower limit value of the temperature of part 11A possibly lower than the delivery temperature of the lower limit of preset range.
In addition, even if delivery temperature ET ratio ET3 high, when delivery temperature ET when ET3 is between ET4 target offset amount also by It is set as 0.Here, since the delivery temperature ET of prediction is close to fiducial temperature, so even if the delivery temperature ET in prediction compares base In the case that quasi- temperature is high, the amount for giving the heat of sensor element 11A is also few, so in the range of the temperature, even if not making Target temperature changes, and the temperature of sensor element 11A is also the value close to fiducial temperature.Therefore, when delivery temperature ET exists When ET3 is between ET4, target offset amount is set as 0 without bringing it about variation.Thereby, it is possible to simplified controls.But Can be, though delivery temperature ET in ET3 between ET4, also identical, the exhaust when ET4 is between ET5 with delivery temperature ET The temperature ET the low, keeps target offset amount smaller.Even if target temperature or target offset amount is not made to change, ET4 can also make For the temperature convergence of sensor element 11A can be found out in the upper limit of the delivery temperature ET in preset range.ET1,ET2, Respectively value can first pass through in advance experiment or simulation etc. to find out by ET3, ET4, ET5.
In addition, being vented the amount of the heat seized from sensor element 11A per unit time can also send out according to the flow of exhaust Changing.Therefore, other than considering delivery temperature ET, it is also contemplated that the flow of exhaust sets target offset amount.For example, In the case that ET3 in delivery temperature ET ratio Fig. 3 is low, even if delivery temperature ET is identical, the flow of exhaust is more, then sensor The speed that the temperature of element 11A reduces also becomes bigger.On the other hand, the situation of the ET3 high in delivery temperature ET ratio Fig. 3 Under, even if delivery temperature ET is identical, the flow of exhaust is more, then the speed that the temperature of sensor element 11A rises also becomes to get over Greatly.In this way, correspondingly with the flow of exhaust, the speed of the temperature change of sensor element 11A creates a difference, so also having can The temperature of energy sensor element 11A will not change immediately as delivery temperature ET but need to spend a degree of time.Therefore, When being made the target offset amount of sensor element 11A change according to delivery temperature ET, it is possible to relative to sensor member The increase and decrease amount of heat in part 11A, target offset amount can exceedingly change and the predetermined model of temperature departure of sensor element 11A It encloses.
Accordingly it is also possible to correct target offset amount according to the flow of exhaust.For the stream around air-fuel ratio sensor 11 For the prediction of the flow of logical exhaust because with controlled in torque-demand used in accelerator opening or in torque-demand The internal-combustion engine rotational speed calculated in control is related with engine load rate, so carrying out the prediction based on these values.In addition, interior Combustion engine revolving speed and engine load rate with when internal combustion engine 1 is operated with the internal-combustion engine rotational speed and engine load rate from internal combustion engine 1 The flow of exhaust when the exhaust arrival air-fuel ratio sensor 11 of outflow is related, so first passing through experiment or simulation etc. in advance to find out The relationship and mapped and be stored in ECU10.
Fig. 4 is the figure for correcting target offset amount shown in Fig. 3.The longitudinal axis is the delivery temperature ET of prediction, and horizontal axis is pre- The extraction flow EQ of survey.Extraction flow EQ is the row around the air-fuel ratio sensor 11 predicted according to the operating condition of internal combustion engine 1 The flow of gas is calculated based on accelerator opening used in controlling in torque-demand." not correcting " in Fig. 4 indicates not correct Target offset amount shown in Fig. 3, " small " expression is so that the mode (side that negative value becomes larger that target offset amount shown in Fig. 3 becomes smaller Formula) it is modified, it is " big " to indicate so that the mode (mode that positive value becomes larger) that target offset amount shown in Fig. 3 becomes larger is repaired Just.
As shown in figure 4, in the case where the extraction flow EQ of prediction is fewer than predetermined amount of flow, no matter the delivery temperature ET of prediction How, all amendments without the target offset amount based on extraction flow EQ.Predetermined amount of flow described herein is by based on Fig. 3 Shown in target offset amount the temperature of sensor element 11A can be controlled within a predetermined range implementing element impedance control Extraction flow upper limit value.That is, extraction flow EQ is to sensor element in the case where extraction flow EQ is fewer than predetermined amount of flow The influence that the temperature of 11A rises or temperature reduces is small, so the amendment without target offset amount corresponding with extraction flow EQ. Therefore, relationship according to Fig.3, carrys out the target temperature of setting sensor element 11A.
On the other hand, even if in the case where the extraction flow EQ of prediction is more than predetermined amount of flow, if delivery temperature ET is Temperature near fiducial temperature, the then influence that extraction flow EQ rises the temperature of sensor element 11A or temperature reduces are small.Cause This, since the temperature departure preset range of sensor element 11A can be inhibited, so without mesh corresponding with extraction flow EQ Mark the amendment of offset.Therefore, relationship according to Fig.3, carrys out the target temperature of setting sensor element 11A.Exhaust at this time The lower and upper limit of temperature ET can be set to ET2 and ET4 in Fig. 3, also can be set to the value different from ET2 and ET4.The value Experiment or simulation etc. can be first passed through in advance to find out.
In addition, in the range of using " small " expression in Fig. 4, even if delivery temperature ET is identical, also so that the exhaust of prediction Flow it is more when the small mode of target offset amount of target offset amount when becoming fewer than the flow of the exhaust of prediction (that is, so that Obtain target temperature and deviate the mode that the bias of fiducial temperature becomes much larger) it is modified.It is pre- in the extraction flow EQ ratio of prediction In the case where the upper limit for height for the range that constant flow is more and the delivery temperature ET ratio of prediction is not with " correcting " indicates, because from being vented receiving Heat and caused by sensor element 11A the speed that rises of temperature and the flow of exhaust correspondingly become larger.Therefore, according to exhaust Flow corrects the target offset amount obtained based on Fig. 3.But the lower limit of revised target offset amount is set as shown in Fig. 3 Lower limit (such as -30 DEG C).Inhibit the sensor member in the case where deviation occurs in the prediction of delivery temperature or extraction flow as a result, This case that the temperature departure preset range of part 11A.In the range, delivery temperature ET high and extraction flow EQ is more, thus in advance The temperature for measuring sensor element 11A can be further up, so passing through the temperature for further decreasing sensor element 11A in advance It is more than the upper limit of preset range to inhibit the temperature of sensor element 11A.
On the other hand, in Fig. 4 use " big " expression in the range of, even if delivery temperature ET is identical, also so that predict The big mode of target offset amount when target offset amount when the flow of exhaust is more becomes fewer than the flow of the exhaust of prediction (that is, So that target temperature deviates the mode that the bias of fiducial temperature becomes much larger) it is modified.In the extraction flow EQ of prediction More than predetermined amount of flow and in the case that the lower limit of range that the delivery temperature ET ratio of prediction is indicated with " not correcting " is low, because being vented Seize heat and caused by sensor element 11A the speed that reduces of temperature and the flow of exhaust correspondingly become larger.Therefore, according to row The flow of gas corrects the target offset amount obtained based on Fig. 3.But the upper limit of revised target offset amount is set as Fig. 3 institute The upper limit (such as+30 DEG C) shown.Inhibit to sense in the case where deviation occurs in the prediction of delivery temperature or extraction flow as a result, This case that the temperature departure preset range of device element 11A.In the range, delivery temperature ET is low and extraction flow EQ is more, by This temperature for predicting sensor element 11A can further decrease, so by further increasing sensor element 11A's in advance Temperature come inhibit sensor element 11A temperature be lower than preset range lower limit.
In addition, being provided with the range of " not correcting " but it is also possible to be alternatively, being not provided with " not correcting " in Fig. 4 Range, if delivery temperature ET is identical, so that target temperature when extraction flow EQ is more deviates the bias of fiducial temperature Bias when fewer than extraction flow EQ big mode corrects target offset amount.
Furthermore, it is possible to by target offset amount shown in Fig. 3 multiplied by the correction factor obtained by relationship shown in Fig. 4 Obtain new target offset amount, can also first pass through experiment or simulation etc. in advance find out delivery temperature ET and extraction flow EQ with The relationship and mapped of target offset amount and be stored in ECU10.
Fig. 5 is to show to assume the constant various values in the case where benchmark temperature of the target temperature of sensor element 11A Passage time diagram.Speed, accelerator opening, the temperature of exhaust, the flow of exhaust, sensor element are successively indicated from upper Temperature, the duty ratio (heater duty cycle) of heater 11B of 11A.The temperature of exhaust and the flow of exhaust are passed in air-fuel ratio Value around sensor 11 is equal with the flow of the temperature of the exhaust of above-mentioned prediction and the exhaust of prediction.Sensor element 11A Temperature in chain-dotted line indicate that the target temperature in element impedance control, solid line indicate actual temperature.In addition, in Fig. 5, The constant target temperature of sensor element 11A is benchmark temperature.Fig. 5, which can also be used as, is implementing previous element impedance control In the case where time diagram.
Become larger in T1 accelerator opening to which speed rises.In the gas that T1 is discharged from internal combustion engine 1 until reaching air-fuel ratio It is spent until sensor 11 a degree of time (time until from T1 to T2).T2 after the operating lag, air-fuel ratio The temperature of exhaust around sensor 11 and the flow of exhaust start to increase.In Fig. 5, compare benchmark in the temperature of the exhaust of T2 Temperature is low, so the increase of the flow with exhaust, the amount of the heat seized from sensor element 11A increases.Therefore, in exhaust After the increase of flow, start to reduce in the temperature of T3 sensor element 11A.
Increase heater duty cycle from T3 in order to increase the temperature of sensor element 11A, but sensor element 11A Temperature has little time to rise, and the temperature of sensor element 11A reduces.The temperature reduction of sensor element 11A continues to arranges in T4 The temperature of gas reaches fiducial temperature.Therefore, during until playing T4 from T3, the temperature of sensor element 11A becomes than pre- The lower limit for determining range is low.When the temperature being vented in T4 is more than fiducial temperature, by being vented come heating sensor element 11A, institute Terminated with the temperature reduction of sensor element 11A.Therefore, heater duty cycle becomes hardly to increase.Hereafter and, by adding Hot device 11B and exhaust carry out heating sensor element 11A, so the temperature of sensor element 11A rises.
Become 0 in T5 accelerator opening, speed starts to reduce.Adjoint accelerator opening becomes 0 and speed reduces, exhaust Flow tails off, so even if the temperature of exhaust becomes fiducial temperature hereinafter, due to can be by heater 11B to sensor element 11A is heated, so the temperature of sensor element 11A also persistently rises.Hereafter, the temperature of sensor element 11A reaches base Quasi- temperature.
In this way, when by the target temperature of sensor element 11A it is constant be benchmark temperature when, in the low situation of the temperature of exhaust Under, the temperature of sensor element 11A becomes lower than the lower limit of preset range sometimes.
On the other hand, Fig. 6 is shown implement sensor element impedance of the present embodiment control in the case where The time diagram of the passage of various values.In the same manner as Fig. 5, Cong Shangqi successively indicates speed, accelerator opening, the temperature of exhaust, row The flow of gas, the temperature of sensor element 11A, the duty ratio of heater 11B.In addition, speed, accelerator opening in Fig. 6, row The temperature of gas, the passage of the flow of exhaust are identical as the passage in Fig. 5.In addition, sensor element resistance of the present embodiment Anti- control is since T11.
When T11 accelerator opening becomes larger, the temperature of ECU10 prediction exhaust and the flow of exhaust, sensor element 11A Target temperature change immediately.With the exhaust of the accelerator opening in T11 increased around accordingly air-fuel ratio sensor 11 Temperature and the flow of exhaust change in T12, but the rising of more early than T12 the target temperature for starting sensor element 11A. That is, the temperature of the exhaust of prediction is lower than fiducial temperature and predicts the flow of exhaust and will increase, so the preparatory raising from T11 The target temperature of sensor element 11A, so that the temperature of sensor element 11A does not reduce.Therefore, heater accounts for from T11 Sky is than increasing.Hereafter and, the temperature of exhaust and the flow of exhaust are successively predicted, adjusts sensor element 11A corresponding to which Target temperature.
It is reached around air-fuel ratio sensor 11 in the exhaust of the T11 temperature predicted and flow in T12.At this point, even if The actual temperature of sensor element 11A become than fiducial temperature is high and the flow for the exhaust that temperature is low increases, also inhibit pass The temperature of sensor component 11A becomes lower than the lower limit of preset range.
In addition, the temperature of exhaust reaches fiducial temperature in T13.Therefore, after T13, heating sensor element 11A quilt Heating exhaust gas, so reducing target temperature so that the temperature of sensor element 11A reduces.Therefore, heater duty cycle also subtracts It is small.Also, start to reduce in T14 speed.
In this way, the flow for working as the exhaust of the temperature and prediction according to the exhaust of prediction makes the target temperature of sensor element 11A When degree changes, even if being also able to suppress sensor element 11A in the case where more than low in the temperature of exhaust and exhaust flow Temperature become lower than the lower limit of preset range.
Fig. 7 is the flow chart for showing the process for setting the duty ratio in element impedance control of the present embodiment.This Flow chart is executed at every predetermined time by ECU10.In addition, element impedance control is separately executed by ECU10.
The temperature for predicting exhaust in step s101 predicts the flow of exhaust in step s 102.Exhaust described herein Temperature and the flow of exhaust be the temperature of exhaust around air-fuel ratio sensor 11 and the flow of exhaust.Based in torque-demand The internal-combustion engine rotational speed and engine load rate calculated in control calculates the temperature of the exhaust in future and the flow of exhaust.In the calculating It is middle to use mapping.This is mapped as also allowing for the temperature of exhaust caused by shedding of heat when circulating in exhaust channel 2 because being vented Spend reduced mapping.In addition, in the present embodiment, ECU10 is and handling step S101 as temperature prediction portion It plays a role.In addition, in the present embodiment, ECU10 is played and handling step S102 as volume forecasting portion Effect.
In step s 103, temperature based on the exhaust calculated in step s101 and the exhaust calculated in step s 102 Flow calculate sensor element 11A target temperature.Mapping is used in the calculating of the target temperature.
In step S104, the duty ratio in element impedance control is calculated.The relationship of target temperature and duty ratio is led in advance Experiment or simulation etc. are crossed to find out.Also, the duty ratio calculated in step S104 in step s105, is set as element resistance Duty ratio in anti-control.In addition, in the present embodiment, ECU10 is and handling step S103 to step S105 It plays a role as control unit.
In addition, if the temperature of sensor element 11A mutates, sensor element 11A damage sometimes, sensor element The characteristic of 11A changes and detected value deviates.It therefore, can also be with when changing the target temperature of sensor element 11A Target temperature is set gradually to change ands upper limit etc. is arranged in the pace of change to target temperature to inhibit sensor element 11A Damage, detected value deviation.The upper limit of the pace of change of target temperature is as the damage for being able to suppress sensor element 11A The deviation pace of change within the allowable range of the detected value of pace of change or air-fuel ratio sensor 11, first pass through in advance experiment or Simulation etc. is found out.
In the present embodiment, the temperature of exhaust and the flow of exhaust are predicted, and based on these values come setting sensor member The target temperature of part 11A, but can also be used as substitution, only predict the temperature of exhaust, and based on the value come setting sensor element The target temperature of 11A.That is, being also possible to set target offset amount based on relationship shown in Fig. 3, but without being based on Fig. 4 institute The amendment for the relationship shown.Here, the flow of exhaust is more, then in the case where the temperature of the exhaust of prediction is higher than fiducial temperature The easier rising of the temperature of sensor element 11A.On the other hand, the situation lower than fiducial temperature in the temperature of the exhaust of prediction Under, the flow of exhaust is more, then the temperature of sensor element 11A is more easily reduced.Accordingly, it is considered to which the flow of exhaust passes to set The target temperature of sensor component 11A can be realized the higher temperature control of precision.But even if in the flow for not considering exhaust In the case where, it also can be according to the variation of the temperature of exhaust come the target temperature of setting sensor element 11A, so can not also Set target temperature with considering the flow of exhaust.
Fig. 8 is to show the duty ratio set in element impedance control of the present embodiment and the flow for not considering exhaust In the case where process flow chart.This flow chart is executed at every predetermined time by ECU10.In addition, element impedance controls It is separately executed by ECU10.
In step s 201, the temperature of exhaust is predicted.The temperature of exhaust described herein indicates air-fuel ratio sensor 11 weeks The temperature for the exhaust enclosed.The row for calculating future based on the internal-combustion engine rotational speed calculated in torque-demand controls and engine load rate The temperature of gas.Mapping is used in the calculating.This is mapped as also allowing for dissipating for heat when circulating in exhaust channel 2 because being vented The mapping that the temperature of exhaust caused by out reduces.In addition, in the present embodiment, ECU10 is by handling step S201 And it plays a role as temperature prediction portion.
In step S202, the temperature based on the exhaust calculated in step s 201 calculates the target of sensor element 11A Temperature.Mapping is used in the calculating of the target temperature.
In step S203, the duty ratio in element impedance control is calculated.The relationship of target temperature and duty ratio is led in advance Experiment or simulation etc. are crossed to find out.Also, in step S204, the duty ratio calculated in step S203 is set as element resistance Duty ratio in anti-control.In addition, in the present embodiment, ECU10 is and handling step S202 to step S204 It plays a role as control unit.
As discussed above, according to the present embodiment, the extraction flow of delivery temperature and prediction based on prediction The target temperature in element impedance control is set, before delivery temperature and extraction flow actually change changes sensor The temperature of element 11A, so being able to suppress this case that the temperature for having little time to adjust sensor element 11A.Thereby, it is possible to will pass The temperature of sensor component 11A maintains within a predetermined range, so being able to suppress the detection accuracy of air-fuel ratio sensor 11 reduces.
It is also contemplated that even if based on prediction delivery temperature and extraction flow make sensor element 11A's in advance In the case that temperature changes, the exhaust of the temperature of the prediction is also reached before the temperature change of sensor element 11A is completed The case where air-fuel ratio sensor 11.That is, the temperature that may also have little time to carry out sensor element 11A sometimes adjusts.But even if In this case, the temperature adjustment of sensor element 11A is begun to before also actually arriving in from exhaust.Therefore, with passing The temperature of sensor component 11A starts sensor element 11A temperature adjustment after changing is compared, and can start to pass earlier The temperature of sensor component 11A adjusts, so a degree of effect is anticipated.
In addition, in the present embodiment, enumerates and be illustrated for air-fuel ratio sensor 11, but can also be suitable for tool The other sensors of having heaters.For example, in the case where controlling heater in PM sensor, NOx sensor, HC sensor Also it can be applicable in the same manner as present embodiment.In addition, in the present embodiment based on being obtained in torque-demand controls in Combustion engine revolving speed and engine load rate predict delivery temperature, but can also be used as substitution, are directly detected by temperature sensor 12 The temperature for the gas being discharged from internal combustion engine 1.In such a situation it is preferred that temperature sensor 12 is configured as close possible to 1 ground of internal combustion engine. Also, detect that the exhaust of temperature reaches sky and circulation in exhaust channel 2 by the temperature sensor 12 by further estimating Temperature until firing than sensor 11 reduces, and can predict the temperature of the exhaust around air-fuel ratio sensor 11.In addition, being not limited to The internal-combustion engine rotational speed and engine load rate obtained in torque-demand control, due to being based on being detected by crankshaft position sensor 21 Internal-combustion engine rotational speed out and the engine load rate detected by accelerator opening sensor 22 can be estimated and be discharged from internal combustion engine 1 Gas temperature, so can also predict the temperature of the exhaust around air-fuel ratio sensor 11 based on the temperature of the gas. The temperature or the exhaust around air-fuel ratio sensor 11 of internal-combustion engine rotational speed and engine load and the gas from the discharge of internal combustion engine 1 The relationship of temperature can first pass through in advance experiment or simulation etc. to find out.
In addition, the aperture of air throttle 8 is related with the temperature of gas being discharged from internal combustion engine 1, so solar term can also be based on Door 8 aperture come predict from internal combustion engine 1 be discharged gas temperature.It is flowed in exhaust channel 2 by further estimating the exhaust Logical and until reaching air-fuel ratio sensor 11 temperature reduces, and can predict the temperature of the exhaust around air-fuel ratio sensor 11.
(embodiment 2)
In the embodiment 1, the temperature of exhaust and the flow of exhaust are predicted based on accelerator opening etc., are based on the prediction To the temperature of exhaust and the flow of exhaust carry out the target temperature of setting sensor element 11A.On the other hand, in embodiment 2 In, according to the target temperature of the direct setting sensor element 11A of accelerator opening.Here, become much larger in accelerator opening In the case of, the requirement torque of internal combustion engine 1 becomes much larger, so inhaled air volume and fuel injection amount increase, the temperature of exhaust becomes Get Geng Gao, and the flow being vented becomes more.Similarly, in the case where accelerator opening becomes smaller situation, internal combustion engine 1 is wanted Torque is asked to become smaller, so the temperature of exhaust becomes lower, and the flow being vented becomes less.Like this, accelerator is opened It spends related with the flow of the temperature of exhaust and exhaust.Therefore, in present embodiment, the case where accelerator opening becomes much larger Under, the temperature of sensor element 11A may become higher, so further decreasing the temperature of sensor element 11A in advance.It is another Aspect, in the case where accelerator opening becomes smaller situation, the temperature of sensor element 11A may become lower, so pre- advanced The temperature of one step raising sensor element 11A.
Fig. 9 is the flow chart for showing the process for setting the duty ratio in element impedance control of the present embodiment.This Flow chart is executed at every predetermined time by ECU10.In addition, element impedance control is separately executed by ECU10.
In step S301, accelerator opening is detected.Accelerator opening is detected by accelerator opening sensor 22.In step In rapid S302, the target temperature of sensor element 11A is calculated based on the accelerator opening detected in step S301.In the mesh It marks in the calculating of temperature using mapping.The mapping so that sensor element 11A when big accelerator opening target temperature ratio The target temperature of the sensor element 11A of accelerator opening hour low mode is set.Indicate accelerator opening and sensor The mapping of the relationship of the target temperature of element 11A first passes through experiment or simulation etc. in advance to find out and be stored in ECU10.In addition, should It is mapped as mapping as following: in the temperature for making the exhaust around air-fuel ratio sensor 11 than the base of sensor element 11A In the case where accelerator opening as quasi- temperature height, the target temperature of sensor element 11A is made to reduce lower than fiducial temperature, The temperature of exhaust around air-fuel ratio sensor 11 such accelerator lower than the fiducial temperature of sensor element 11A is opened In the case where degree, the target temperature of sensor element 11A is made to improve higher than fiducial temperature.In turn, this is mapped as target temperature Such mapping within a predetermined range.In addition it is also possible to be, ECU10 stores physical model or calculating formula to replace mapping, and root The target temperature of sensor element 11A is calculated according to these.
In step S303, the duty ratio in element impedance control is calculated.The relationship of target temperature and duty ratio is led in advance Experiment or simulation etc. are crossed to find out.Also, the duty ratio calculated in step S303 in step s 304, is set as element resistance Duty ratio in anti-control.In addition, in the present embodiment, ECU10 is and handling step S302 to step S304 It plays a role as control unit.
So, the temperature of sensor element 11A can be easily controlled based on accelerator opening.

Claims (6)

1. a kind of sensing system, has:
Exhaust sensor is set to the exhaust channel of internal combustion engine, has sensor element and adds to the sensor element The heater of heat；
Temperature prediction portion, prediction are provided with the temperature of the exhaust of the internal combustion engine at the position of the exhaust sensor；And
Control unit is to control the heater so that the close target for being contained in preset range of the temperature of the sensor element The control unit of temperature is contained in the preset range in the temperature, that is, predicted temperature ratio for the exhaust predicted by the temperature prediction portion Fiducial temperature it is high in the case where, keep the target temperature high in the predicted temperature in the range lower than the fiducial temperature When compared with when the predicted temperature is low reduce, in the case where the predicted temperature is lower than the fiducial temperature, make the mesh Marking temperature reduces compared with when the predicted temperature is low in the range higher than the fiducial temperature when the predicted temperature is high.
2. sensing system according to claim 1,
It is also equipped with volume forecasting portion, the volume forecasting portion is provided with the exhaust based on the operating condition prediction of the internal combustion engine The flow of the exhaust of the internal combustion engine at the position of sensor,
The control unit is predicted when the flow for the exhaust predicted by the volume forecasting portion is more with by the volume forecasting portion Exhaust flow it is few when it is bigger compared to the bias for making the target temperature deviate the fiducial temperature.
3. sensing system according to claim 1 or 2,
Accelerator opening sensor is also equipped with,
The temperature prediction portion exhaust is predicted based on the accelerator opening detected by the accelerator opening sensor Temperature.
4. sensing system according to claim 2,
Accelerator opening sensor is also equipped with,
The volume forecasting portion exhaust is predicted based on the accelerator opening detected by the accelerator opening sensor Flow.
5. sensing system according to any one of claims 1 to 4,
The upper limit is arranged to pace of change when making the target temperature change in the control unit.
6. a kind of sensing system, has:
Exhaust sensor is set to the exhaust channel of internal combustion engine, has sensor element and adds to the sensor element The heater of heat；
Accelerator opening sensor；And
Control unit controls the heater so that the close target temperature for being contained in preset range of the temperature of the sensor element Degree,
The control unit is making benchmark of the temperature of the exhaust around the exhaust sensor than being contained in the preset range In the case where accelerator opening as temperature height, make the target temperature in the range lower than the fiducial temperature described It is reduced compared with the accelerator opening hour when accelerator opening is big, in the temperature for making the exhaust around the exhaust sensor In the case where spending such accelerator opening lower than the fiducial temperature, make the target temperature higher than the fiducial temperature It is reduced compared with the accelerator opening hour in range when the accelerator opening is big.
CN201811311725.7A 2017-11-07 2018-11-06 Sensing system Pending CN109751107A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2017214657A JP2019085926A (en) 2017-11-07 2017-11-07 Sensor system
JP2017-214657 2017-11-07

Publications (1)

Publication Number Publication Date
CN109751107A true CN109751107A (en) 2019-05-14

Family

ID=66328390

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201811311725.7A Pending CN109751107A (en) 2017-11-07 2018-11-06 Sensing system

Country Status (3)

Country Link
US (1) US20190136738A1 (en)
JP (1) JP2019085926A (en)
CN (1) CN109751107A (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017014772A1 (en) * 2015-07-22 2017-01-26 Cummins Inc. System and method for controlling exhaust gas temperature

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0994345A2 (en) * 1998-10-13 2000-04-19 Denso Corporation Power supply control system for heater used in gas concentration sensor
CA2299933A1 (en) * 1999-03-04 2000-09-04 Toyota Jidosha Kabushiki Kaisha Control device for an air-fuel ratio sensor
CN101363809A (en) * 2007-08-08 2009-02-11 雅马哈发动机株式会社 Gas sensor, air-fuel ratio controller, and transportation apparatus
CN101592095A (en) * 2007-12-07 2009-12-02 通用汽车环球科技运作公司 Oxygen sensor heater control strategy
CN102189991A (en) * 2010-03-12 2011-09-21 通用汽车环球科技运作有限责任公司 Control system and method for oxygen sensor heater control
CN103140819A (en) * 2010-10-06 2013-06-05 罗伯特·博世有限公司 Method for adjusting a temperature of a sensor element
CN103562533A (en) * 2011-06-02 2014-02-05 博世株式会社 Heater control device for oxygen concentration sensor
CN105697167A (en) * 2014-12-12 2016-06-22 福特环球技术公司 Oxygen sensor control responsive to resistance and impedance

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0994345A2 (en) * 1998-10-13 2000-04-19 Denso Corporation Power supply control system for heater used in gas concentration sensor
CA2299933A1 (en) * 1999-03-04 2000-09-04 Toyota Jidosha Kabushiki Kaisha Control device for an air-fuel ratio sensor
CN101363809A (en) * 2007-08-08 2009-02-11 雅马哈发动机株式会社 Gas sensor, air-fuel ratio controller, and transportation apparatus
CN101592095A (en) * 2007-12-07 2009-12-02 通用汽车环球科技运作公司 Oxygen sensor heater control strategy
CN102189991A (en) * 2010-03-12 2011-09-21 通用汽车环球科技运作有限责任公司 Control system and method for oxygen sensor heater control
CN103140819A (en) * 2010-10-06 2013-06-05 罗伯特·博世有限公司 Method for adjusting a temperature of a sensor element
CN103562533A (en) * 2011-06-02 2014-02-05 博世株式会社 Heater control device for oxygen concentration sensor
CN105697167A (en) * 2014-12-12 2016-06-22 福特环球技术公司 Oxygen sensor control responsive to resistance and impedance

Also Published As

Publication number Publication date
US20190136738A1 (en) 2019-05-09
JP2019085926A (en) 2019-06-06

Similar Documents

Publication Publication Date Title
US8603310B2 (en) Gas-concentration/humidity detection apparatus
JP5126388B2 (en) Gas sensor control device
JP7055641B2 (en) Combustion control method for vehicle engine and vehicle engine system
JP2006161625A (en) Exhaust temperature estimating device for internal combustion engine
US10753305B2 (en) Combustion control method in vehicle engine and engine system for vehicle
US20170067386A1 (en) Exhaust gas purification device for internal combustion engine
JP3800068B2 (en) Gas concentration sensor heater control device
US6712054B2 (en) Device and method for measuring element temperature of air-fuel ratio sensor, and device and method for controlling heater of air-fuel ratio sensor
CN101389953B (en) Temperature control apparatus for heater-equipped sensor
JP5696789B2 (en) Control device for internal combustion engine
CN109751107A (en) Sensing system
US10718285B2 (en) Combustion control method in vehicle engine and engine system for vehicle
US11078858B2 (en) Control apparatus for an internal combustion engine
JP3524373B2 (en) Heater control device for air-fuel ratio sensor
US20170356392A1 (en) Control device of internal combustion engine
JP6756317B2 (en) Internal combustion engine exhaust system
CN107532533A (en) Air-fuel ratio control device and air/fuel ratio control method
JP2000356618A (en) Measuring method for characteristic of gas concentration sensor
CN110131061A (en) Sensing system
JP4556504B2 (en) Concentration detector
JP5565295B2 (en) Exhaust gas recirculation control device for internal combustion engine
JPH0610739A (en) Air-fuel ratio controller of engine
CN105612336B (en) It can avoid the engine control system of the error detection of sensor
JP2022153758A (en) Sensor element and gas sensor
JP2022153759A (en) Sensor element and gas sensor

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
WD01 Invention patent application deemed withdrawn after publication

Application publication date: 20190514

WD01 Invention patent application deemed withdrawn after publication