CN114962034A - Hybrid vehicle type engine wide-area oxygen sensor degradation diagnosis method - Google Patents

Hybrid vehicle type engine wide-area oxygen sensor degradation diagnosis method Download PDF

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Publication number
CN114962034A
CN114962034A CN202210642965.5A CN202210642965A CN114962034A CN 114962034 A CN114962034 A CN 114962034A CN 202210642965 A CN202210642965 A CN 202210642965A CN 114962034 A CN114962034 A CN 114962034A
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Prior art keywords
oxygen sensor
wide
fault
equivalence ratio
ratio
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CN114962034B (en
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李京
王冬
张珍
张德全
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Dongfeng Motor Corp
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Dongfeng Motor Corp
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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
    • F02D41/22—Safety or indicating devices for abnormal conditions
    • F02D41/222—Safety or indicating devices for abnormal conditions relating to the failure of sensors or parameter detection devices
    • 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
    • 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
    • F02D41/22—Safety or indicating devices for abnormal conditions
    • 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
    • F02D41/3005—Details not otherwise provided for
    • 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

The invention discloses a hybrid vehicle type engine wide-area oxygen sensor degradation diagnosis method, which comprises the following steps: collecting an oxygen concentration signal of exhaust gas in an exhaust pipe after combustion through a wide-range oxygen sensor; calculating an air-fuel ratio according to the oxygen concentration signal to generate an actual air-fuel ratio signal; controlling the fuel injection quantity and the fuel injection timing of the engine to adjust the air-fuel ratio according to the air-fuel ratio signal to generate an adjusted actual air-fuel ratio signal; respectively establishing an actual fuel equivalence ratio and a target fuel equivalence ratio according to the ideal air-fuel ratio, the adjusted actual air-fuel ratio and a preset target air-fuel ratio; and selecting corresponding degradation diagnosis according to the ratio of the oxygen storage amount of the catalyst to the total oxygen storage amount, and judging whether the wide-area oxygen sensor fails. According to the invention, the fuel equivalence ratio reflection conditions in the air-fuel ratio control process of different degrees are monitored under the steady state working condition, and whether the wide-range oxygen sensor is deteriorated or invalid is verified.

Description

Hybrid vehicle type engine wide-area oxygen sensor degradation diagnosis method
Technical Field
The invention belongs to the field of engine control, and particularly relates to a method for diagnosing degradation of a wide-range oxygen sensor of a hybrid vehicle engine.
Background
The wide-range oxygen sensor is an important sensor as closed-loop control of the air-fuel ratio, and can accurately output a signal of the air-fuel ratio.
In the light automobile pollutant emission limit and measurement method (sixth stage of china), the diagnostic requirements for the front oxygen sensor are explicitly set forth: OBD systems monitor the failure of pre-oxygen sensors (sensors for fuel control, conventional switch-type oxygen sensors and/or wide-area or universal sensors) including output voltage, response rate and parameters that may affect emissions.
The hybrid vehicle type (including an engine, a driving motor and a generator) is a popular vehicle type at present, and the hybrid vehicle type includes the engine. The range and the running time of the engine running working condition in the hybrid vehicle type are much narrower than those of a transmission gasoline vehicle, and the purpose is to improve the fuel economy, the vehicle drivability, the emission performance, the NVH and the like.
When the wide-area oxygen sensor has performance faults, if the rich-lean change of the air-fuel ratio cannot be accurately reflected, the wide-area oxygen sensor needs to be diagnosed in time. After the fault occurs, the fault post-treatment is carried out in time, so that the influence on fuel economy, vehicle drivability, emission performance, NVH and the like is reduced.
Disclosure of Invention
The invention aims to provide a method for diagnosing the degradation of a wide-range oxygen sensor of a hybrid vehicle engine, which monitors the fuel equivalence ratio reflection condition in the air-fuel ratio control process of different degrees under the steady-state working condition and verifies whether the wide-range oxygen sensor is degraded and invalid or not.
In order to solve the technical problems, the technical scheme of the invention is as follows: the method for diagnosing the degradation of the wide-range oxygen sensor of the hybrid vehicle engine comprises the following steps:
collecting an oxygen concentration signal of exhaust gas in an exhaust pipe after combustion through a wide-range oxygen sensor;
calculating an air-fuel ratio according to the oxygen concentration signal to generate an actual air-fuel ratio signal;
controlling the fuel injection quantity and the fuel injection timing of the engine to adjust the air-fuel ratio according to the air-fuel ratio signal to generate an adjusted actual air-fuel ratio signal;
respectively establishing an actual fuel equivalence ratio and a target fuel equivalence ratio according to the ideal air-fuel ratio, the adjusted actual air-fuel ratio and a preset target air-fuel ratio; wherein, the actual fuel equivalence ratio is represented as the ratio of the adjusted actual air-fuel ratio to the ideal air-fuel ratio, and the target fuel equivalence ratio is represented as the ratio of the target air-fuel ratio to the ideal air-fuel ratio;
and selecting corresponding degradation diagnosis according to the ratio of the oxygen storage amount of the catalyst to the total oxygen storage amount, and judging whether the wide-range oxygen sensor fails.
Before the degradation diagnosis is carried out, working condition detection is carried out, and the working condition detection comprises the following steps:
the rotating speed of the engine is in a certain range; the relevant diagnosis of the engine speed does not have faults;
the engine has no oil cut;
the heating of the wide-range oxygen sensor is completed, namely the wide-range oxygen sensor is within the normal working temperature; no fault occurs in the wide-range oxygen sensor heating diagnosis;
the accelerator is not fully opened, and the opening degree of an accelerator pedal is in a certain range; the accelerator opening sensor diagnoses no fault;
the temperature of the engine cooling water exceeds a certain value; the cooling temperature sensor is diagnosed without fault;
the temperature of the intake manifold of the engine exceeds a certain value; no fault occurs in the intake manifold temperature sensor diagnosis;
when the running time of the engine exceeds a certain value, the engine is successfully warmed up;
the air inflow in the air inlet cylinder is in a certain range; relevant diagnosis for monitoring or calculating the air input does not have faults;
the vehicle speed exceeds a certain value; the related diagnosis of the vehicle speed does not have fault;
and when the working condition is met, allowing the wide-range oxygen sensor to enter the degradation diagnosis.
After the operating mode condition satisfies, carry out operating mode stable condition and detect, operating mode stable condition includes:
the engine speed fluctuates within a certain range;
the opening degree of an accelerator pedal fluctuates within a certain range;
the vehicle speed fluctuates within a certain range;
the amount of intake air entering the cylinder fluctuates within a certain range;
and after the working condition stable condition and the working condition are both met, performing degradation diagnosis on the wide-range oxygen sensor.
After the working condition stable condition and the working condition are both met, when the ratio of the oxygen storage amount of the catalyst to the total oxygen storage amount is smaller than a first oxygen storage amount threshold value r1, periodically controlling the target fuel equivalence ratio, wherein the oxygen storage amount of the catalyst is insufficient at the moment, and the first preset time T is used Base Performing an enrichment operation, the enrichment operation comprising: increasing the oxygen concentration and setting the equivalence ratio of the enriched target fuel oil to r FEQRRichBase Greater than 1, and then for a second preset time T Min Performing a lean-down operation, the lean-down operation comprising: reducing the oxygen concentration and setting the lean target fuel equivalence ratio to r FEQRLeanBase Less than 1; alternately repeating the enrichment operation and the enleanment operation for N0 times respectively, recording the actual fuel equivalence ratio fed back by the upstream wide-range oxygen sensor in real time, and calculating the first partial-concentration reflecting time T of the actual fuel equivalence ratio RichResDn And a second rich partial reflecting time T RichResUp (ii) a Wherein T is Base Greater than T Min ；
T RichResDn The method for judging the initial calculation time comprises the following steps: actual fuel equivalence ratio and r in current sampling period FEQRRichBase Is less than the preset difference value delta C, and the actual fuel equivalence ratio and r in the next sampling period FEQRRichBase Is greater than or equal to Δ C; before the actual fuel equivalence ratio in the subsequent sampling period is greater than 1 +/-delta C for the first time, the actual fuel equivalence ratio in the current sampling period is greater than or equal to the actual fuel equivalence ratios in all the subsequent sampling periods;
T RichResDn the judgment method for ending the calculation time comprises the following steps: the absolute value of the difference between the actual fuel equivalence ratio and 1 in the current sampling period is smaller than deltaC, and the absolute value of the difference between the actual fuel equivalence ratio and 1 in the next sampling period is larger than or equal to deltaC; the actual fuel equivalence ratio is greater than r for the first time in the subsequent sampling period FEQRLeanBase Before +/-Delta C, the actual fuel equivalence ratio of the current sampling period is greater than or equal to the actual fuel equivalence ratios of all the subsequent sampling periods;
T RichResUp the method for starting to calculate the time comprises the following steps: the absolute value of the difference between the actual fuel equivalence ratio and 1 in the current sampling period is smaller than deltaC, and the absolute value of the difference between the actual fuel equivalence ratio and 1 in the next sampling period is larger than or equal to deltaC; the actual fuel equivalence ratio is greater than r for the first time in the subsequent sampling period FEQRRichBase Before +/-Delta C, the actual fuel equivalence ratio of the current sampling period is less than or equal to the actual fuel equivalence ratios of all the subsequent sampling periods;
T RichResUp method for ending calculation time: actual fuel equivalence ratio and r in current sampling period FEQRRichBase Is less than deltac and the actual fuel equivalence ratio in the next sampling period is less than r FEQRRichBase Is greater than or equal to Δ C; before the actual fuel equivalence ratio in the subsequent sampling period is greater than 1 +/-delta C for the first time, the actual fuel equivalence ratio in the current sampling period is greater than or equal to the actual fuel equivalence ratios in all the subsequent sampling periods;
at T RichResDn Read three elements T arbitrarily RichResDn11 ，T RichResDn12 And T RichResDn13 ，T RichResDn N0 elements corresponding to the enrichment operation times exist in the array, the initial 2 elements and the tail 2 elements are removed to obtain (N0-4) elements, and the average value corresponding to the (N0-4) elements is calculated to obtain
Figure BDA0003682917720000041
Figure BDA0003682917720000042
And
Figure BDA0003682917720000043
at T RichResUp Read three elements T arbitrarily RichResUp11 ，T RichResUp12 And T RichResUp13 ，T RichResUp Corresponding enrichment operation in arrayRemoving the initial 2 elements and the tail 2 elements of the N0 elements of the times to obtain (N0-4) elements, and calculating the average value corresponding to the (N0-4) elements to obtain
Figure BDA0003682917720000044
Figure BDA0003682917720000045
And
Figure BDA0003682917720000046
and when any one of the following conditions occurs, judging that the wide-area oxygen sensor has a fault:
Figure BDA0003682917720000047
is greater than
Figure BDA0003682917720000048
Judging that the wide-area oxygen sensor has a fault; wherein
Figure BDA0003682917720000049
The average cylinder fresh air intake flow after entering the diagnosis; d 2 ，d 1 ，d 0 Respectively a second evaluation coefficient, a first evaluation coefficient and an initial evaluation coefficient, wherein d 2 ，d 1 ，d 0 At different r FEQRRichBase Then, the fitting data is obtained according to the calibration matching data of the fault oxygen sensor and the fault-free oxygen sensor;
(2)
Figure BDA0003682917720000051
is greater than
Figure BDA0003682917720000052
Judging that the wide-area oxygen sensor has a fault; d 5 ，d 4 ，d 3 Respectively a fifth evaluation coefficient, a fourth evaluation coefficient and a third evaluation coefficient, wherein d 5 ，d 4 ，d 3 At different r FEQRRichBase Then, the fitting data is obtained according to the calibration fitting data of the fault oxygen sensor and the fault-free oxygen sensor;
(3)
Figure BDA0003682917720000053
and
Figure BDA0003682917720000054
the absolute value of the difference between the two values,
Figure BDA0003682917720000055
and
Figure BDA0003682917720000056
the absolute value of the difference between the two values,
Figure BDA0003682917720000057
and
Figure BDA0003682917720000058
any one of the absolute values of the difference is greater than
Figure BDA0003682917720000059
Judging that the wide-area oxygen sensor has a fault; d is a radical of 9 ，d 8 Respectively a ninth evaluation coefficient and an eighth evaluation coefficient, wherein d 9 ，d 8 At a different place
Figure BDA00036829177200000510
Then, the fitting data is obtained according to the calibration matching data of the fault oxygen sensor and the fault-free oxygen sensor;
when any fault is determined in the above 3 types of fault diagnosis, the degradation diagnosis is not performed in the current driving cycle.
After the working condition stable condition and the working condition are both met, when the ratio of the oxygen storage amount of the catalyst to the total oxygen storage amount is larger than or equal to a first oxygen storage amount threshold value r1 and smaller than or equal to a second oxygen storage amount threshold value r2, the target fuel equivalence ratio is periodically controlled, the oxygen storage amount of the catalyst is sufficient at the moment, and the first preset time T is used for Base Carrying out an enrichment operation and then setting a first preset time T Base Carrying out a thinning operation; repeating the enrichment operation and the lean-down operation for N0 times alternately, recording the actual fuel equivalence ratio fed back by the upstream wide-range oxygen sensor in real time, and calculating the first rich-bias reflecting time T of the actual fuel equivalence ratio RichResDn Second rich reflecting time T RichResUp First partial dilution reflecting time T LeanResDn And a second lean reflection time T LeanResUp ；
T LeanResDn The method for judging the initial calculation time comprises the following steps: the absolute value of the difference between the actual fuel equivalence ratio and 1 in the current sampling period is smaller than a preset difference value delta C, and the absolute value of the difference between the actual fuel equivalence ratio and 1 in the next sampling period is larger than or equal to delta C; the actual fuel equivalence ratio is greater than r for the first time in the subsequent sampling period FEQRLeanBase Before +/-Delta C, the actual fuel equivalence ratio of the current sampling period is greater than or equal to the actual fuel equivalence ratios of all the subsequent sampling periods;
T LeanResDn the judgment method for ending the calculation time comprises the following steps: actual fuel equivalence ratio and r in current sampling period FEQRLeanBase Is less than deltac and the actual fuel equivalence ratio is compared with r in the next sampling period FEQRLeanBase Is greater than or equal to Δ C; before the actual fuel equivalence ratio in the subsequent sampling period is greater than 1 +/-delta C for the first time, the actual fuel equivalence ratio in the current sampling period is greater than or equal to the actual fuel equivalence ratios in all the subsequent sampling periods;
T LeanResUp the method for starting to calculate the time comprises the following steps: actual fuel equivalence ratio and r in current sampling period FEQRLeanBase Is less than deltac and the actual fuel equivalence ratio is compared with r in the next sampling period FEQRLeanBase Is greater than or equal to Δ C; before the actual fuel equivalence ratio in the subsequent sampling period is greater than 1 +/-delta C for the first time, the actual fuel equivalence ratio in the current sampling period is less than or equal to the actual fuel equivalence ratios in all the subsequent sampling periods;
T LeanResUp method for ending calculation time: the absolute value of the difference between the actual fuel equivalence ratio and 1 in the current sampling period is smaller than deltaC, and the difference between the actual fuel equivalence ratio and 1 in the next sampling period is absoluteFor values greater than or equal to Δ C; the actual fuel equivalence ratio is greater than r for the first time in the subsequent sampling period FEQRLeanBase Before +/-Delta C, the actual fuel equivalence ratio of the current sampling period is greater than or equal to the actual fuel equivalence ratios of all the subsequent sampling periods;
at T LeanResDn Read three elements T arbitrarily LeanResDn11 ，T LeanResDn12 And T LeanResDn13 ，T LeanResDn N0 elements corresponding to the number of enrichment operations exist in the array, the initial 2 elements and the tail 2 elements are removed to obtain (N0-4) elements, and the average value corresponding to the (N0-4) elements is calculated to obtain
Figure BDA0003682917720000061
Figure BDA0003682917720000062
And
Figure BDA0003682917720000063
at T LeanResUp Respectively corresponding to read T LeanResUp11 ，T LeanResUp12 And T LeanResUp13 ，T LeanResUp N0 elements corresponding to the enrichment operation times exist in the array, the initial 2 elements and the tail 2 elements are removed to obtain (N0-4) elements, and the average value corresponding to the (N0-4) elements is calculated to obtain
Figure BDA0003682917720000064
And
Figure BDA0003682917720000065
and when any one of the following conditions occurs, judging that the wide-area oxygen sensor has a fault:
(4)
Figure BDA0003682917720000066
and
Figure BDA0003682917720000067
at any time inIs greater than
Figure BDA0003682917720000071
Judging that the wide-area oxygen sensor has a fault;
(5)
Figure BDA0003682917720000072
and
Figure BDA0003682917720000073
is greater than
Figure BDA0003682917720000074
Judging that the wide-area oxygen sensor has a fault;
(6)
Figure BDA0003682917720000075
and
Figure BDA0003682917720000076
the absolute value of the difference between the two values,
Figure BDA0003682917720000077
and
Figure BDA0003682917720000078
the absolute value of the difference between the two values,
Figure BDA0003682917720000079
and
Figure BDA00036829177200000710
the absolute value of the difference between the two values,
Figure BDA00036829177200000711
and
Figure BDA00036829177200000712
the absolute value of the difference between the two values,
Figure BDA00036829177200000713
and
Figure BDA00036829177200000714
the absolute value of the difference between the two values,
Figure BDA00036829177200000715
and
Figure BDA00036829177200000716
any one of the absolute values of the difference is greater than
Figure BDA00036829177200000717
Judging that the wide-area oxygen sensor has a fault; d 7 ，d 6 Respectively is, wherein d 7 ，d 6 At different r FEQRRichBase Then, the fitting data is obtained according to the calibration matching data of the fault oxygen sensor and the fault-free oxygen sensor;
(7)
Figure BDA00036829177200000718
and
Figure BDA00036829177200000719
the absolute value of the difference between the two values,
Figure BDA00036829177200000720
and
Figure BDA00036829177200000721
the absolute value of the difference between the two values,
Figure BDA00036829177200000722
and
Figure BDA00036829177200000723
the absolute value of the difference between the two values,
Figure BDA00036829177200000724
and
Figure BDA00036829177200000725
the absolute value of the difference between the two values,
Figure BDA00036829177200000726
and
Figure BDA00036829177200000727
the absolute value of the difference between the two values,
Figure BDA00036829177200000728
and
Figure BDA00036829177200000729
any one of the absolute values of the difference is greater than
Figure BDA00036829177200000730
Judging that the wide-area oxygen sensor has a fault;
when any fault is determined in the above 4 types of fault diagnosis, the degradation diagnosis is not performed in the current driving cycle.
After the working condition stable condition and the working condition are both met, when the ratio of oxygen storage amount of the catalyst to total oxygen storage amount is greater than r2, the oxygen storage amount is too high at the moment, and the first preset time T is used Base Performing a lean-down operation, and then performing a second preset time T Min Carrying out thickening operation; alternately repeating the lean operation and the rich operation for N0 times, recording the actual fuel equivalence ratio fed back by the upstream wide-range oxygen sensor in real time, and calculating the first lean reflection time T of the actual fuel equivalence ratio LeanResDn And a second lean reflection time T LeanResUp ；
And when any one of the following conditions occurs, judging that the wide-area oxygen sensor has a fault:
(8)
Figure BDA00036829177200000731
and
Figure BDA00036829177200000732
is greater than
Figure BDA00036829177200000733
Judging that the wide-area oxygen sensor has a fault;
(9)
Figure BDA0003682917720000081
and
Figure BDA0003682917720000082
is greater than
Figure BDA0003682917720000083
Judging that the wide-area oxygen sensor has a fault;
(10)
Figure BDA0003682917720000084
and
Figure BDA0003682917720000085
the absolute value of the difference between the two values,
Figure BDA0003682917720000086
and
Figure BDA0003682917720000087
the absolute value of the difference between the two values,
Figure BDA0003682917720000088
and
Figure BDA0003682917720000089
any one of the absolute values of the difference is greater than
Figure BDA00036829177200000810
Judging that the wide-area oxygen sensor has a fault;
when any fault is determined in the above 3 types of fault diagnosis, the degradation diagnosis is not performed in the current driving cycle.
The stoichiometric air-fuel ratio was 14.3.
r1 is 0.13.
r2 is 0.89.
The predetermined difference Δ C is 0.002.
Compared with the prior art, the invention has the beneficial effects that:
the method monitors the fuel equivalence ratio reflection condition in the air-fuel ratio control process of different degrees under the steady state working condition, and can verify whether the wide-range oxygen sensor is deteriorated or invalid.
Drawings
FIG. 1 is a schematic flow chart of an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
The technical scheme of the invention is as follows: a method for diagnosing deterioration of a wide-range oxygen sensor of a hybrid vehicle engine.
The control system comprises an engine controller EMS, a wide-range oxygen sensor intelligent driving chip and a wide-range oxygen sensor.
The wide-range oxygen sensor is used for providing a current oxygen concentration signal in exhaust gas in the exhaust pipe after combustion to an engine controller EMS;
the intelligent driving chip of the wide-area oxygen sensor collects and processes an oxygen concentration signal monitored by the wide-area oxygen sensor, converts the oxygen concentration signal into an air-fuel ratio related signal, and heats the wide-area oxygen sensor to ensure that the oxygen sensor works at a normal temperature;
and the engine controller EMS adjusts the air-fuel ratio in the engine cylinder by controlling the fuel injection quantity, the fuel injection timing and the like of the engine according to the air-fuel ratio related signal in the exhaust pipe processed by the intelligent chip of the wide-range oxygen sensor.
The oxygen concentration in the exhaust pipe is too low and is called as 'over-concentration'; too high a concentration of oxygen in the exhaust pipe is called "over-lean";
the wide-range oxygen sensor provides the current concentration of air in the exhaust pipe to an engine controller EMS, and the current concentration is represented by using the reciprocal of an excess air coefficient lambda, namely a fuel equivalence ratio, in the embodiment, FEQR is used for representing the fuel equivalence ratio:
Figure BDA0003682917720000091
then setting the target air-fuel ratio may be done by setting the target FEQR, then there is a target
Figure BDA0003682917720000092
"actual fuel" refers to the actual amount of fuel entering the cylinder per unit time, "actual air" refers to the actual amount of fresh air entering the cylinder per unit time, "target fuel" refers to the target amount of fuel entering the cylinder per unit time, "target air" refers to the target amount of fresh air entering the cylinder per unit time, "ideal air" refers to the ideal amount of fresh air entering the cylinder per unit time, and "ideal fuel" refers to the ideal amount of fuel entering the cylinder per unit time. The "target" is not equal to the "ideal", the target value can be actively changed according to the engine operating conditions, but the ideal value is determined by the oil.
When the engine is out of oil, the FEQR is 0; when the concentration is too high, the FEQR is more than 1; when the concentration is too dilute, the FEQR is less than 1; when the FEQR is equal to 1, the air-fuel ratio is currently at the stoichiometric air-fuel ratio (FEQR is equal to 1, which means the ratio of the actual air amount to the actual fuel amount, and the ratio of the stoichiometric air amount to the stoichiometric fuel amount are equal to each other, the stoichiometric air-fuel ratio is 14.3 in the present embodiment).
Fault diagnosis of the wide-range oxygen sensor needs to be carried out under certain working conditions;
1. the rotating speed of the engine is in a certain range; engine speed related diagnostics (crankshaft signal and cam signal diagnostics) are not faulted;
2. the engine has no oil cut;
3. the oxygen sensor heating is completed, i.e. the oxygen sensor is already within normal operating temperature; no fault occurs in the heating diagnosis of the oxygen sensor;
4. the accelerator is not fully opened (the accelerator is fully opened to enrich the air-fuel ratio under the full accelerator so as to improve the torque capacity of the full accelerator), and the opening degree of an accelerator pedal is in a certain range (less than or equal to 95%); the accelerator opening sensor diagnoses no fault;
5. the temperature of the engine cooling water exceeds a certain value; the cooling temperature sensor is diagnosed to have no fault;
6. the temperature of the intake manifold of the engine exceeds a certain value; no fault occurs in the intake manifold temperature sensor diagnosis;
7. when the running time of the engine exceeds a certain value, the engine is successfully warmed up;
8. the air inflow in the air inlet cylinder is in a certain range; relevant diagnostics for monitoring or calculating intake air amount (e.g., intake manifold pressure, throttle sensor, and throttle motor, etc.) do not fail.
9. The vehicle speed exceeds a certain value; vehicle speed related diagnostics are not faulted.
After the working condition is met, the fault diagnosis of the wide-range oxygen sensor is allowed to enter, but in the diagnosis process, the working condition needs to be ensured to be stable:
1. the engine speed fluctuates within a certain range; this example takes. + -. 20rpm
2. The opening degree of an accelerator pedal fluctuates within a certain range; this example takes. + -. 2%
3. The vehicle speed fluctuates within a certain range; this example takes. + -.2 kmph
4. The amount of intake air taken into the cylinder fluctuates within a certain range. In this example, +/-2 mgpl is taken
And after all the working condition conditions and the working condition stable conditions are met, performing fault diagnosis on the wide-range oxygen sensor.
In any process of fault diagnosis of the wide-range oxygen sensor, if any one of the working condition conditions (except the condition of the actual air-fuel ratio) is not met or any one of the working condition stable conditions (except the condition of the actual air-fuel ratio) is not met, the diagnosis is stopped, and the diagnosis is started again after the next working condition is met.
a) Once the ratio of the catalyst oxygen storage amount to the total oxygen storage amount is not less than r1 (0.13 in the present embodiment) and not more than r2 (0.89 in the present embodiment), the failure diagnosis of b and c in the present driving cycle is not completed. The oxygen storage amount of the catalyst is enough, and the emission is less influenced by actively controlling the air-fuel ratio to be rich or lean at the moment.
Periodically controlling target FEQR after all working condition conditions and working condition stable conditions are met, namely, controlling air-fuel ratio time T by enrichment Base (time T) Base In this example, 1.4s is taken, and the target FEQR is set to r FEQRRichBase Greater than 1), followed by lean-down control of the air-fuel ratio for a preset time T Base (setting target FEQR as r FEQRLeanBase Less than 1), repeatedly controlling for N0 times (10 can be taken in the embodiment, namely 10 periodically controlling FEQR) in such a way, recording the actual FEQR fed back by the upstream wide-area oxygen sensor in real time, and calculating the partial concentration reflecting time T of the actual FEQR RichResDn And T RichResUp Calculating the actual FEQR partial-thin reflecting time T LeanResDn And T LeanResUp 。
T RichResDn The method for starting to calculate the time comprises the following steps: actual FEQR and r at current sampling period (all sampling periods in this embodiment take 2ms) FEQRRichBase The absolute value of the difference is smaller than Δ C (in this embodiment, Δ C is 0.002), and the actual FEQR and r in the next sampling period FEQRRichBase Is not less than Δ C. Before the actual FEQR appears for the first time in the subsequent sampling period to be more than 1 +/-delta C, the actual FEQR of the current sampling period is not less than the actual FEQR of all the subsequent sampling periods.
T RichResDn The method for ending the calculation of the time comprises the following steps: the absolute value of the difference between the actual FEQR and 1 in the current sampling period is smaller than deltaC, and the absolute value of the difference between the actual FEQR and 1 in the next sampling period is not smaller than deltaC. Actual FEQR first occurrence of more than r in subsequent sampling periods FEQRLeanBase Before Δ C, the actual FEQR for the current sampling period is not less than the actual FEQR for all of the subsequent sampling periods.
T RichResUp The method for starting to calculate the time comprises the following steps: the absolute value of the difference between the actual FEQR and 1 in the current sampling period is smaller than deltaC, and the absolute value of the difference between the actual FEQR and 1 in the next sampling period is not smaller than deltaC. Actual FEQR first appears to be greater than r in subsequent sampling periods FEQRRichBase Before Δ C, the actual FEQR for the current sampling period is not greater than the actual FEQR for all of the subsequent sampling periods.
T RichResUp Method for ending calculation time:pre-sampling period actual FEQR and r FEQRRichBase Is less than Δ C (in this embodiment, Δ C is 0.002), and the actual FEQR and r are obtained in the next sampling period FEQRRichBase Is not less than Δ C. Before the actual FEQR appears for the first time in the subsequent sampling period to be more than 1 +/-delta C, the actual FEQR of the current sampling period is not less than the actual FEQR of all the subsequent sampling periods.
T LeanResDn The method for starting to calculate the time comprises the following steps: the absolute value of the difference between the actual FEQR and 1 in the current sampling period is smaller than deltaC, and the absolute value of the difference between the actual FEQR and 1 in the next sampling period is not smaller than deltaC. Actual FEQR first occurrence of greater than r in subsequent sampling cycles FEQRLeanBase Before Δ C, the actual FEQR for the current sampling period is not less than the actual FEQR for all of the subsequent sampling periods.
T LeanResDn Method for ending calculation time: actual FEQR and r at current sampling period FEQRLeanBase The absolute value of the difference is smaller than Δ C (in this embodiment, Δ C is 0.002), and the actual FEQR and r in the next sampling period FEQRLeanBase Is not less than Δ C. Before the actual FEQR appears for the first time in the subsequent sampling period to be more than 1 +/-delta C, the actual FEQR of the current sampling period is not more than the actual FEQR of all the subsequent sampling periods.
T LeanResUp The method for starting to calculate the time comprises the following steps: actual FEQR and r at current sampling period FEQRLeanBase The absolute value of the difference is smaller than Δ C (in this embodiment, Δ C is 0.002), and the actual FEQR and r in the next sampling period FEQRLeanBase Is not less than Δ C. Before the actual FEQR appears for the first time in the subsequent sampling period to be more than 1 +/-delta C, the actual FEQR of the current sampling period is not more than the actual FEQR of all the subsequent sampling periods.
T LeanResUp Method for ending calculation time: the absolute value of the difference between the actual FEQR and 1 in the current sampling period is smaller than deltaC, and the absolute value of the difference between the actual FEQR and 1 in the next sampling period is not smaller than deltaC. Actual FEQR first appears to be greater than r in subsequent sampling cycles FEQRLeanBase Before Δ C, the actual FEQR for the current sampling period is not greater than the actual FEQR for all of the subsequent sampling periods.
Reading the current actual FEQR, the actual FEQR at the time of entry diagnosis, sets the target FEQR r FEQRRichBase The present examples are FEQR +0.02, FEQR +0.05, FEQR +0.1, and target FEQR ═ r FEQRLeanBase Taking 2FEQR-r FEQRRichBase (i.e., N0 cycles of FEQR +0.02 and FEQR-0.02, N0 cycles of FEQR +0.05 and FEQR-0.05, and N0 cycles of FEQR +0.1 and FEQR-0.1).
T RichResDn Respectively correspond to read T RichResDn11 ，T RichResDn12 And T RichResDn13 And all the N-numbered arrays are composed of N0 numbers, the number of heads is 2, the number of tails is 2 are eliminated (the data deviation caused by the instability of a control system when FEQR active control is just introduced is avoided, so that the data accuracy is improved), N0-4 numbers are obtained, and the average value corresponding to the N0-4 numbers is calculated to obtain the average value
Figure BDA0003682917720000131
And
Figure BDA0003682917720000132
T RichResUp respectively correspond to the read T RichResUp11 ，T RichResUp12 And T RichResUp13 And all the N-numbered arrays are composed of N0 numbers, the number of the heads is 2, the number of the tails is 2, N0-4 is obtained, and the average value corresponding to the number of the heads N0-4 is calculated to obtain
Figure BDA0003682917720000133
And
Figure BDA0003682917720000134
T LeanResDn respectively correspond to the read T LeanResDn11 ，T LeanResDn12 And T LeanResDn13 And all the N-numbered arrays are composed of N0 numbers, the number of the heads is 2, the number of the tails is 2, N0-4 is obtained, and the average value corresponding to the number of the heads N0-4 is calculated to obtain
Figure BDA0003682917720000135
And
Figure BDA0003682917720000136
T LeanResUp respectively correspond to the read T LeanResUp11 ，T LeanResUp12 And T LeanResUp13 And the number of the arrays is N0, the number of the heads is 2, the number of the tails is 2, the number of the heads is N0-4, and the average value corresponding to the number of the heads N0-4 is calculated to obtain
Figure BDA0003682917720000137
And
Figure BDA0003682917720000138
the wide area oxygen sensor fails if any of the following occurs:
1.
Figure BDA0003682917720000139
and
Figure BDA00036829177200001310
any 1 of 6 times greater than
Figure BDA00036829177200001311
The wide-area oxygen sensor fails; wherein
Figure BDA00036829177200001312
The average cylinder fresh air intake flow after entering the diagnostics. d 2 ，d 1 ，d 0 Respectively taking the value of-80.232 (ms mgps) 2 ) 3520.23(ms mgps),0.034(ms), at different r FEQRRichBase And then, obtaining the fitting data according to the fault oxygen sensor and the fault-free oxygen sensor.
2.
Figure BDA00036829177200001313
And
Figure BDA00036829177200001314
any 1 of 6 times greater than
Figure BDA00036829177200001315
The wide-area oxygen sensor fails; d 5 ，d 4 ，d 3 Respectively take 4538.245 (ms/mgps) 2 ) -1108.524(ms/mgps),77.376(ms), at different r FEQRRichBase And then, obtaining the fitting data according to the fault oxygen sensor and the fault-free oxygen sensor.
3.
Figure BDA0003682917720000141
And
Figure BDA0003682917720000142
the absolute value of the difference (or
Figure BDA0003682917720000143
And
Figure BDA0003682917720000144
the absolute value of the difference, or
Figure BDA0003682917720000145
And
Figure BDA0003682917720000146
the absolute value of the difference therebetween),
Figure BDA0003682917720000147
and
Figure BDA0003682917720000148
the absolute value of the difference (or
Figure BDA0003682917720000149
And
Figure BDA00036829177200001410
the absolute value of the difference, or
Figure BDA00036829177200001411
And
Figure BDA00036829177200001412
absolute value of difference) is greater than
Figure BDA00036829177200001413
The wide-area oxygen sensor fails; d is a radical of 7 ，d 6 The values are respectively 0.12(ms) and 2.376(ms) at different r FEQRRichBase And then, obtaining the fitting data according to the fault oxygen sensor and the fault-free oxygen sensor.
4.
Figure BDA00036829177200001414
And
Figure BDA00036829177200001415
the absolute value of the difference (or
Figure BDA00036829177200001416
And
Figure BDA00036829177200001417
the absolute value of the difference, or
Figure BDA00036829177200001418
And
Figure BDA00036829177200001419
the absolute value of the difference between them),
Figure BDA00036829177200001420
and
Figure BDA00036829177200001421
the absolute value of the difference (or
Figure BDA00036829177200001422
And
Figure BDA00036829177200001423
the absolute value of the difference, or
Figure BDA00036829177200001424
And
Figure BDA00036829177200001425
absolute value of difference) is greater than
Figure BDA00036829177200001426
The wide-area oxygen sensor fails; d 9 ，d 8 The values are respectively 0.201(ms) and 0.531(ms), and the values are different
Figure BDA00036829177200001427
And then, obtaining the fitting data according to the fault oxygen sensor and the fault-free oxygen sensor.
After any fault occurs in the above 4 fault diagnoses, the driving cycle is not diagnosed any more.
b) Once the ratio of the oxygen storage amount of the catalyst to the total oxygen storage amount is smaller than r1 (0.13 is taken in the embodiment), the fault diagnosis of a and c in the driving cycle is not completed.
After all working condition conditions and working condition stable conditions are met, the oxygen storage amount is insufficient at the moment, and in order to reduce the influence on emission, the target FEQR is periodically controlled, namely the air-fuel ratio time T is controlled to be enriched Base (time T) Base In this example, 1.4s is taken, and the target FEQR is set to r FEQRRichBase Greater than 1), then immediately set the target FEQR to r FEQRLeanBase Less than 1 time T Min (time T) Min 0.1s is taken in the embodiment), the control is repeated for N0 times (10 is taken in the embodiment, namely 10 periodic control FEQR are taken), the actual FEQR fed back by the upstream wide-area oxygen sensor is recorded in real time, and the partial concentration reflecting time T of the actual FEQR is calculated RichResDn And T RichResUp . Obtained by the same method
Figure BDA0003682917720000151
Figure BDA0003682917720000152
And
Figure BDA0003682917720000153
the same method is used for fault diagnosis:
1.
Figure BDA0003682917720000154
any 1 of 3 times greater than
Figure BDA0003682917720000155
The wide-area oxygen sensor fails; wherein
Figure BDA0003682917720000156
The average cylinder fresh air intake flow after entering the diagnostics. d is a radical of 2 ，d 1 ，d 0 Respectively taking the value of-80.232 (ms mgps) 2 ) 3520.23(ms mgps),0.034(ms), at different r FEQRRichBase And then, obtaining the fitting data according to the fault oxygen sensor and the fault-free oxygen sensor.
2.
Figure BDA0003682917720000157
Any 1 of 3 times greater than
Figure BDA0003682917720000158
The wide-area oxygen sensor fails; d 5 ，d 4 ，d 3 Respectively take 4538.245 (ms/mgps) 2 ) 1108.524(ms/mgps),77.376(ms), at different r FEQRRichBase And then, obtaining the fitting data according to the fault oxygen sensor and the fault-free oxygen sensor.
3.
Figure BDA0003682917720000159
And
Figure BDA00036829177200001510
the absolute value of the difference (or
Figure BDA00036829177200001511
And
Figure BDA00036829177200001512
the absolute value of the difference, or
Figure BDA00036829177200001513
And
Figure BDA00036829177200001514
absolute value of difference) of greater than
Figure BDA00036829177200001515
The wide-area oxygen sensor fails; d 9 ，d 8 The values are respectively 0.201(ms) and 0.531(ms), and the values are different
Figure BDA00036829177200001516
And then, obtaining the fitting data according to the fault oxygen sensor and the fault-free oxygen sensor.
And after any fault occurs in the above 3 fault diagnoses, the driving cycle is not diagnosed any more.
c) Once the ratio of the oxygen storage amount of the catalyst to the total oxygen storage amount is larger than r2 (0.89 is taken in the embodiment), and the fault diagnosis of a and b is not finished in the driving cycle.
After all working condition conditions and working condition stable conditions are met, the oxygen storage amount is not enough, and in order to reduce the influence on the emission, the target FEQR is periodically controlled, namely the thinning ratio time T is reduced Base (time T) Base In this example, 1.4s is taken, and the target FEQR is set to r FEQRRichBase Small 1), then set the target FEQR to r FEQRLeanBase Less than 1 time T Min (time T) Min 0.1s is taken in the embodiment), the control is repeated for N0 times (10 is taken in the embodiment, namely 10 periodic control FEQR are taken), the actual FEQR fed back by the upstream wide-area oxygen sensor is recorded in real time, and the partial dilution reflecting time T of the actual FEQR is calculated LeanResDn And T LeanResUp . Obtained by the same method
Figure BDA0003682917720000161
Figure BDA0003682917720000162
And
Figure BDA0003682917720000163
and
Figure BDA0003682917720000164
the same method is used for fault diagnosis:
1.
Figure BDA0003682917720000165
and
Figure BDA0003682917720000166
any 1 time of 3 is greater than
Figure BDA0003682917720000167
The wide-area oxygen sensor fails; wherein
Figure BDA0003682917720000168
The average cylinder fresh air intake flow rate after the diagnosis is entered. d 2 ，d 1 ，d 0 Respectively taking the value of-80.232 (ms mgps) 2 ) 3520.23(ms mgps),0.034(ms), at different r FEQRRichBase And then, obtaining the fitting data according to the fault oxygen sensor and the fault-free oxygen sensor.
2.
Figure BDA0003682917720000169
And
Figure BDA00036829177200001610
any 1 time of 3 is greater than
Figure BDA00036829177200001611
The wide-area oxygen sensor fails; d 5 ，d 4 ，d 3 Respectively take 4538.245 (ms/mgps) 2 ) -1108.524(ms/mgps),77.376(ms), at different r FEQRRichBase And then, obtaining the fitting data according to the fault oxygen sensor and the fault-free oxygen sensor.
3.
Figure BDA00036829177200001612
And
Figure BDA00036829177200001613
the absolute value of the difference (or
Figure BDA00036829177200001614
And
Figure BDA00036829177200001615
the absolute value of the difference, or
Figure BDA00036829177200001616
And
Figure BDA00036829177200001617
absolute value of difference) is greater than
Figure BDA00036829177200001618
The wide-area oxygen sensor fails; d is a radical of 9 ，d 8 The values are respectively 0.201(ms) and 0.531(ms), and the values are different
Figure BDA00036829177200001619
And then, obtaining the fitting data according to the fault oxygen sensor and the fault-free oxygen sensor.
And after any fault occurs in the above 3 fault diagnoses, the driving cycle is not diagnosed any more.
It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (10)

1. The method for diagnosing the deterioration of the wide-range oxygen sensor of the hybrid vehicle engine is characterized by comprising the following steps:
collecting an oxygen concentration signal of exhaust gas in an exhaust pipe after combustion through a wide-range oxygen sensor;
calculating an air-fuel ratio according to the oxygen concentration signal to generate an actual air-fuel ratio signal;
controlling the fuel injection quantity and the fuel injection timing of the engine to adjust the air-fuel ratio according to the air-fuel ratio signal, and generating an adjusted actual air-fuel ratio signal;
respectively establishing an actual fuel equivalence ratio and a target fuel equivalence ratio according to the ideal air-fuel ratio, the adjusted actual air-fuel ratio and a preset target air-fuel ratio; wherein, the actual fuel equivalence ratio is represented as the ratio of the adjusted actual air-fuel ratio to the ideal air-fuel ratio, and the target fuel equivalence ratio is represented as the ratio of the target air-fuel ratio to the ideal air-fuel ratio;
and selecting corresponding degradation diagnosis according to the ratio of the oxygen storage amount of the catalyst to the total oxygen storage amount, and judging whether the wide-area oxygen sensor fails.
2. The hybrid vehicle engine wide-range oxygen sensor degradation diagnosis method according to claim 1, wherein before performing degradation diagnosis, condition detection is performed, the condition detection including:
the rotating speed of the engine is in a certain range; the relevant diagnosis of the engine speed does not have faults;
the engine has no oil cut;
the heating of the wide-range oxygen sensor is completed, namely the wide-range oxygen sensor is within the normal working temperature; no fault occurs in the wide-area oxygen sensor heating diagnosis;
the accelerator is not fully opened, and the opening degree of an accelerator pedal is in a certain range; the accelerator opening sensor diagnoses no fault;
the temperature of the engine cooling water exceeds a certain value; the cooling temperature sensor is diagnosed without fault;
the temperature of the intake manifold of the engine exceeds a certain value; no fault occurs in the intake manifold temperature sensor diagnosis;
when the running time of the engine exceeds a certain value, the engine is successfully warmed up;
the air inflow in the air inlet cylinder is in a certain range; relevant diagnosis for monitoring or calculating the air input does not have faults;
the vehicle speed exceeds a certain value; the relevant diagnosis of the vehicle speed does not have fault;
and when the working condition is met, allowing the wide-range oxygen sensor to enter the degradation diagnosis.
3. The hybrid vehicle type engine wide-area oxygen sensor degradation diagnosis method according to claim 2, characterized in that after the operating condition is satisfied, the operating condition stable condition detection is performed, the operating condition stable condition including:
the engine speed fluctuates within a certain range;
the opening degree of an accelerator pedal fluctuates within a certain range;
the vehicle speed fluctuates within a certain range;
the amount of intake air entering the cylinder fluctuates within a certain range;
and after the working condition stable condition and the working condition are both met, performing degradation diagnosis on the wide-range oxygen sensor.
4. The method of claim 3, wherein after both steady-state and steady-state operating conditions are met, the target fuel equivalence ratio is periodically controlled when the ratio of the oxygen storage capacity of the catalyst to the total oxygen storage capacity is less than a first threshold value r1, and the oxygen storage capacity of the catalyst is insufficient for a first predetermined period of time TBase Performing an enrichment operation, the enrichment operation comprising: increasing the oxygen concentration and setting the equivalence ratio of the enriched target fuel oil to r FEQRRichBase Greater than 1, and then for a second preset time T Min Performing a lean-down operation, the lean-down operation comprising: reducing the oxygen concentration and setting the lean target fuel equivalence ratio to r FEQRLeanBase Less than 1; repeating the enrichment operation and the lean-down operation for N0 times alternately, recording the actual fuel equivalence ratio fed back by the upstream wide-range oxygen sensor in real time, and calculating the first rich-bias reflecting time T of the actual fuel equivalence ratio RichResDn And a second rich partial reflecting time T RichResUp (ii) a Wherein T is Base Greater than T Min ；
T RichResDn The method for judging the initial calculation time comprises the following steps: actual fuel equivalence ratio and r in current sampling period FEQRRichBase Is less than the preset difference value Delta C, and actually burns in the next sampling periodOil equivalence ratio and r FEQRRichBase Is greater than or equal to Δ C; before the actual fuel equivalence ratio in the subsequent sampling period is greater than 1 +/-delta C for the first time, the actual fuel equivalence ratio in the current sampling period is greater than or equal to the actual fuel equivalence ratios in all the subsequent sampling periods;
T RichResDn the judgment method for ending the calculation time comprises the following steps: the absolute value of the difference between the actual fuel equivalence ratio and 1 in the current sampling period is smaller than deltaC, and the absolute value of the difference between the actual fuel equivalence ratio and 1 in the next sampling period is larger than or equal to deltaC; the actual fuel equivalence ratio is greater than r for the first time in the subsequent sampling period FEQRLeanBase Before +/-Delta C, the actual fuel equivalence ratio of the current sampling period is greater than or equal to the actual fuel equivalence ratios of all the subsequent sampling periods;
T RichResUp the method for starting to calculate the time comprises the following steps: the absolute value of the difference between the actual fuel equivalence ratio and 1 in the current sampling period is smaller than deltaC, and the absolute value of the difference between the actual fuel equivalence ratio and 1 in the next sampling period is larger than or equal to deltaC; the actual fuel equivalence ratio is greater than r for the first time in the subsequent sampling period FEQRRichBase Before +/-Delta C, the actual fuel equivalence ratio of the current sampling period is less than or equal to the actual fuel equivalence ratios of all the subsequent sampling periods;
T RichResUp method for ending calculation time: actual fuel equivalence ratio and r in current sampling period FEQRRichBase Is less than deltac and the actual fuel equivalence ratio in the next sampling period is less than r FEQRRichBase Is greater than or equal to Δ C; before the actual fuel equivalence ratio in the subsequent sampling period is greater than 1 +/-delta C for the first time, the actual fuel equivalence ratio in the current sampling period is greater than or equal to the actual fuel equivalence ratios in all the subsequent sampling periods;
at T RichResDn Read three elements T arbitrarily RichResDn11 ，T RichResDn12 And T RichResDn13 ，T RichResDn N0 elements corresponding to the enrichment operation times exist in the array, the initial 2 elements and the tail 2 elements are removed to obtain (N0-4) elements, and the average value corresponding to the (N0-4) elements is calculated to obtain
Figure FDA0003682917710000031
Figure FDA0003682917710000032
And
Figure FDA0003682917710000033
at T RichResUp Read three elements T arbitrarily RichResUp11 ，T RichResUp12 And T RichResUp13 ，T RichResUp N0 elements corresponding to the enrichment operation times exist in the array, the initial 2 elements and the tail 2 elements are removed to obtain (N0-4) elements, and the average value corresponding to the (N0-4) elements is calculated to obtain
Figure FDA0003682917710000034
Figure FDA0003682917710000035
And
Figure FDA0003682917710000036
and when any one of the following conditions occurs, judging that the wide-area oxygen sensor has a fault:
(1)
Figure FDA0003682917710000037
is greater than
Figure FDA0003682917710000041
Judging that the wide-area oxygen sensor has a fault; wherein
Figure FDA0003682917710000042
The average cylinder fresh air intake flow after entering the diagnosis; d 2 ，d 1 ，d 0 Respectively a second evaluation coefficient, a first evaluation coefficient and an initial evaluation coefficient, whereind 2 ，d 1 ，d 0 At different r FEQRRichBase Then, the fitting data is obtained according to the calibration matching data of the fault oxygen sensor and the fault-free oxygen sensor;
(2)
Figure FDA0003682917710000043
is greater than
Figure FDA0003682917710000044
Judging that the wide-area oxygen sensor has a fault; d 5 ，d 4 ，d 3 Respectively a fifth evaluation coefficient, a fourth evaluation coefficient and a third evaluation coefficient, wherein d 5 ，d 4 ，d 3 At different r FEQRRichBase Then, the fitting data is obtained according to the calibration matching data of the fault oxygen sensor and the fault-free oxygen sensor;
(3)
Figure FDA0003682917710000045
and
Figure FDA0003682917710000046
the absolute value of the difference between the two values,
Figure FDA0003682917710000047
and
Figure FDA0003682917710000048
the absolute value of the difference between the two values,
Figure FDA0003682917710000049
and
Figure FDA00036829177100000410
any one of the absolute values of the difference is greater than
Figure FDA00036829177100000411
Judging that the wide-area oxygen sensor has a fault; d 9 ，d 8 Are respectively the ninthAn evaluation coefficient and an eighth evaluation coefficient, wherein d 9 ，d 8 In a different place
Figure FDA00036829177100000412
Then, the fitting data is obtained according to the calibration matching data of the fault oxygen sensor and the fault-free oxygen sensor;
when any fault is determined in the above 3 types of fault diagnosis, the degradation diagnosis is not performed in the current driving cycle.
5. The method of claim 4, wherein after both steady-state and steady-state operating conditions are met, the target fuel equivalence ratio is periodically controlled when the ratio of the catalyst oxygen storage to the total oxygen storage is greater than or equal to a first threshold r1 and less than or equal to a second threshold r2, the catalyst oxygen storage being sufficient for a first predetermined time T Base Carrying out an enrichment operation and then setting a first preset time T Base Carrying out a thinning operation; repeating the enrichment operation and the lean-down operation for N0 times alternately, recording the actual fuel equivalence ratio fed back by the upstream wide-range oxygen sensor in real time, and calculating the first rich-bias reflecting time T of the actual fuel equivalence ratio RichResDn Second rich reflecting time T RichResUp First partial dilution reflecting time T LeanResDn And a second lean reflection time T LeanResUp ；
T LeanResDn The method for judging the initial calculation time comprises the following steps: the absolute value of the difference between the actual fuel equivalence ratio and 1 in the current sampling period is smaller than a preset difference value delta C, and the absolute value of the difference between the actual fuel equivalence ratio and 1 in the next sampling period is larger than or equal to delta C; the actual fuel equivalence ratio is greater than r for the first time in the subsequent sampling period FEQRLeanBase Before +/-Delta C, the actual fuel equivalence ratio of the current sampling period is greater than or equal to the actual fuel equivalence ratios of all the subsequent sampling periods;
T LeanResDn the judgment method for ending the calculation time comprises the following steps: actual fuel equivalence ratio and r in current sampling period FEQRLeanBase Is less than deltac and the next sampling cycleReal fuel equivalence ratio and r FEQRLeanBase Is greater than or equal to Δ C; before the actual fuel equivalence ratio in the subsequent sampling period is greater than 1 +/-delta C for the first time, the actual fuel equivalence ratio in the current sampling period is greater than or equal to the actual fuel equivalence ratios in all the subsequent sampling periods;
T LeanResUp the method for starting to calculate the time comprises the following steps: actual fuel equivalence ratio and r in current sampling period FEQRLeanBase Is less than deltac and the actual fuel equivalence ratio is compared with r in the next sampling period FEQRLeanBase Is greater than or equal to Δ C; before the actual fuel equivalence ratio in the subsequent sampling period is greater than 1 +/-delta C for the first time, the actual fuel equivalence ratio in the current sampling period is less than or equal to the actual fuel equivalence ratios in all the subsequent sampling periods;
T LeanResUp method for ending calculation time: the absolute value of the difference between the actual fuel equivalence ratio and 1 in the current sampling period is smaller than deltaC, and the absolute value of the difference between the actual fuel equivalence ratio and 1 in the next sampling period is larger than or equal to deltaC; the actual fuel equivalence ratio is greater than r for the first time in the subsequent sampling period FEQRLeanBase Before +/-Delta C, the actual fuel equivalence ratio of the current sampling period is greater than or equal to the actual fuel equivalence ratios of all the subsequent sampling periods;
at T LeanResDn Read three elements T arbitrarily LeanResDn11 ，T LeanResDn12 And T LeanResDn13 ，T LeanResDn N0 elements corresponding to the enrichment operation times exist in the array, the initial 2 elements and the tail 2 elements are removed to obtain (N0-4) elements, and the average value corresponding to the (N0-4) elements is calculated to obtain
Figure FDA0003682917710000051
Figure FDA0003682917710000052
And
Figure FDA0003682917710000053
at T LeanResUp Read three elements T arbitrarily LeanResUp11 ，T LeanResUp12 And T LeanResUp13 ，T LeanResUp N0 elements corresponding to the number of enrichment operations exist in the array, the initial 2 elements and the tail 2 elements are removed to obtain (N0-4) elements, and the average value corresponding to the (N0-4) elements is calculated to obtain
Figure FDA0003682917710000061
Figure FDA0003682917710000062
And
Figure FDA0003682917710000063
and when any one of the following conditions occurs, judging that the wide-area oxygen sensor has a fault:
(4)
Figure FDA0003682917710000064
and
Figure FDA0003682917710000065
is greater than
Figure FDA0003682917710000066
Judging that the wide-area oxygen sensor has a fault;
(5)
Figure FDA0003682917710000067
and
Figure FDA0003682917710000068
is greater than
Figure FDA0003682917710000069
Judging that the wide-area oxygen sensor has a fault;
(6)
Figure FDA00036829177100000610
and
Figure FDA00036829177100000611
the absolute value of the difference between the two values,
Figure FDA00036829177100000612
and
Figure FDA00036829177100000613
the absolute value of the difference between the two values,
Figure FDA00036829177100000614
and
Figure FDA00036829177100000615
the absolute value of the difference between the two values,
Figure FDA00036829177100000616
and
Figure FDA00036829177100000617
the absolute value of the difference between the two values,
Figure FDA00036829177100000618
and
Figure FDA00036829177100000619
the absolute value of the difference between the two values,
Figure FDA00036829177100000620
and
Figure FDA00036829177100000621
any one of the absolute values of the difference is greater than
Figure FDA00036829177100000622
Judging that the wide-area oxygen sensor has a fault; d 7 ，d 6 Respectively a seventh evaluation coefficient and a sixth evaluation coefficient, wherein d 7 ，d 6 At different r FEQRRichBase Then, the fitting data is obtained according to the calibration fitting data of the fault oxygen sensor and the fault-free oxygen sensor;
(7)
Figure FDA00036829177100000623
and
Figure FDA00036829177100000624
the absolute value of the difference between the two values,
Figure FDA00036829177100000625
and
Figure FDA00036829177100000626
the absolute value of the difference between the two values,
Figure FDA00036829177100000627
and
Figure FDA00036829177100000628
the absolute value of the difference between the two values,
Figure FDA00036829177100000629
and
Figure FDA00036829177100000630
the absolute value of the difference between the two values,
Figure FDA00036829177100000631
and
Figure FDA00036829177100000632
the absolute value of the difference between the two values,
Figure FDA00036829177100000633
and
Figure FDA00036829177100000634
any one of the absolute values of the difference is greater than
Figure FDA00036829177100000635
Judging that the wide-area oxygen sensor has a fault;
when any fault is determined in the above 4 types of fault diagnosis, the degradation diagnosis is not performed in the current driving cycle.
6. The method of claim 5, wherein the oxygen storage amount is too high for the first predetermined time T when the ratio of the oxygen storage amount of the catalyst to the total oxygen storage amount is greater than r2 after both the steady-state condition and the steady-state condition are satisfied Base Performing a lean-down operation, and then performing a second preset time T Min Carrying out thickening operation; alternately repeating the lean operation and the rich operation for N0 times, recording the actual fuel equivalence ratio fed back by the upstream wide-range oxygen sensor in real time, and calculating the first lean reflection time T of the actual fuel equivalence ratio LeanResDn And a second lean reaction time T LeanResUp ；
And when any one of the following conditions occurs, judging that the wide-area oxygen sensor has a fault:
(8)
Figure FDA0003682917710000071
and
Figure FDA0003682917710000072
is greater than
Figure FDA0003682917710000073
Judging that the wide-area oxygen sensor has a fault;
(9)
Figure FDA0003682917710000074
and
Figure FDA0003682917710000075
is greater than
Figure FDA0003682917710000076
Judging that the wide-area oxygen sensor has a fault;
(10)
Figure FDA0003682917710000077
and
Figure FDA0003682917710000078
the absolute value of the difference between the two values,
Figure FDA0003682917710000079
and
Figure FDA00036829177100000710
the absolute value of the difference between the two values,
Figure FDA00036829177100000711
and
Figure FDA00036829177100000712
any one of the absolute values of the difference is greater than
Figure FDA00036829177100000713
Judging that the wide-area oxygen sensor has a fault;
when any fault is determined in the above 3 types of fault diagnosis, the degradation diagnosis is not performed in the current driving cycle.
7. The hybrid vehicle engine wide-range oxygen sensor degradation diagnosis method according to claim 1, characterized in that a stoichiometric air-fuel ratio is 14.3.
8. The hybrid vehicle engine wide-range oxygen sensor deterioration diagnosis method according to claim 4 or 5, wherein r1 is 0.13.
9. The hybrid vehicle engine wide-range oxygen sensor deterioration diagnosis method according to claim 5 or 6, wherein r2 is 0.89.
10. The hybrid vehicle engine wide-range oxygen sensor deterioration diagnosis method according to any one of claims 4 to 6, wherein the preset difference value Δ C is 0.002.
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