CN115126584B - A method and device for detecting removal of a three-way catalytic converter - Google Patents

Abstract

The application discloses a method and a device for detecting removal of a three-way catalyst. The method comprises the following steps: controlling the engine to resume supplying fuel to deoxidize the three-way catalyst; in the deoxidation process of the three-way catalyst, determining the change trend of the detection value of the rear oxygen sensor according to the detection values of the rear oxygen sensor at a plurality of different moments; when the change trend indicates that there is an inflection point detection value among the post-oxygen sensor detection values at a plurality of different times, it is determined that the three-way catalyst is removed. In the deoxidizing process of the three-way catalyst, the removal detection of the three-way catalyst is carried out by combining the detection value of the rear oxygen sensor, if the inflection point detection value exists in the change trend corresponding to the detection value of the rear oxygen sensor, the three-way catalyst is removed under the abnormal condition that the rear oxygen sensor is transformed can be represented, so that the accurate judgment of whether the three-way catalyst is removed or not is realized.

Description

A method and device for detecting removal of a three-way catalytic converter

Technical Field

The present application relates to the field of automobile engineering technology, and in particular to a method and device for detecting removal of a three-way catalytic converter.

Background technique

The three-way catalytic converter is an exhaust gas treatment device installed in the exhaust system of the engine. It can convert harmful gases such as carbon monoxide, hydrocarbons, and nitrogen oxides in the exhaust gas into harmless carbon dioxide, water, and nitrogen through redox reactions. However, since the three-way catalytic converter contains precious metals, it is often removed by humans to steal the precious metals, resulting in the inability to properly treat the exhaust gas, causing environmental pollution.

In order to solve this problem, it is generally possible to determine whether the three-way catalytic converter has been removed by detecting its conversion efficiency. When the conversion efficiency of the three-way catalytic converter decreases, it is determined that the three-way catalytic converter has been removed. However, when the three-way catalytic converter is removed, if the rear oxygen sensor is modified, that is, a cavity is added to the rear oxygen sensor, then the conversion efficiency of the three-way catalytic converter detected thereafter may be similar to the conversion efficiency when the three-way catalytic converter is installed, resulting in an inability to effectively and accurately determine whether the three-way catalytic converter has been removed.

Summary of the invention

The embodiments of the present application provide a method and device for detecting removal of a three-way catalytic converter, so as to accurately and effectively determine whether the three-way catalytic converter has been removed.

In a first aspect, an embodiment of the present application provides a method for detecting removal of a three-way catalytic converter, comprising:

Controlling the engine to resume fuel supply to deoxygenate the three-way catalytic converter;

During the deoxygenation process of the three-way catalytic converter, determining a change trend of the detection value of the rear oxygen sensor according to the detection values of the rear oxygen sensor at multiple different moments;

When the variation trend indicates that there is an inflection point detection value among the rear oxygen sensor detection values at the plurality of different times, it is determined that the three-way catalyst is removed.

Optionally, determining a change trend of the rear oxygen sensor detection value according to the rear oxygen sensor detection values at a plurality of different moments includes:

Determining an average value of the rear oxygen sensor detection values at the plurality of different moments according to the rear oxygen sensor detection values at the plurality of different moments;

The change trend is determined according to the average value and a preset reference average value when the three-way catalytic converter is not removed.

Optionally, determining the change trend according to the average value and a preset reference average value when the three-way catalytic converter is not removed includes:

When the average value matches the preset reference average value, the change trend is determined as a steady upward trend; the steady upward trend is used to indicate that the inflection point detection value does not exist in the rear oxygen sensor detection values at the plurality of different moments;

When the average value does not match the preset reference average value, the change trend is determined as a fluctuating upward trend; the fluctuating upward trend is used to indicate that the inflection point detection value exists in the rear oxygen sensor detection values at the plurality of different moments.

Optionally, before controlling the engine to resume supplying fuel, the method further includes:

The engine is controlled to enter a reverse drag condition to store oxygen in the three-way catalytic converter until a front oxygen sensor detection value is equal to a preset front oxygen sensor detection value.

Optionally, the method further comprises:

When the rear oxygen sensor detection value is greater than or equal to a preset rear oxygen sensor detection value, and/or the change trend of the front oxygen sensor detection value does not conform to a preset change trend, the collection of the rear oxygen sensor detection value is stopped.

In a second aspect, an embodiment of the present application provides a three-way catalytic converter removal detection device, comprising:

A deoxygenation control module, used for controlling the engine to resume supplying fuel so as to deoxygenate the three-way catalytic converter;

A variation trend determination module, used for determining, during the deoxygenation process of the three-way catalytic converter, a variation trend of the detection value of the rear oxygen sensor according to the detection values of the rear oxygen sensor at multiple different moments;

The removal detection module is used to determine that the three-way catalytic converter is removed when the change trend indicates that there is an inflection point detection value in the rear oxygen sensor detection values at the multiple different time points.

Optionally, the change trend determination module specifically includes:

A first determining module, configured to determine an average value of the rear oxygen sensor detection values at the plurality of different moments according to the rear oxygen sensor detection values at the plurality of different moments;

The second determination module is used to determine the change trend according to the average value and a preset reference average value when the three-way catalytic converter is not removed.

Optionally, the second determining module is specifically configured to:

When the average value matches the preset reference average value, the change trend is determined as a steady upward trend; the steady upward trend is used to indicate that the inflection point detection value does not exist in the rear oxygen sensor detection values at the plurality of different moments;

When the average value does not match the preset reference average value, the change trend is determined as a fluctuating upward trend; the fluctuating upward trend is used to indicate that the inflection point detection value exists in the rear oxygen sensor detection values at the plurality of different moments.

Optionally, the device further comprises:

The oxygen storage control module is used to control the engine to enter a reverse drag condition so as to store oxygen in the three-way catalytic converter until the front oxygen sensor detection value is equal to a preset front oxygen sensor detection value.

Optionally, the device further comprises:

The data processing module is used to stop collecting the rear oxygen sensor detection value when the rear oxygen sensor detection value is greater than or equal to a preset rear oxygen sensor detection value and/or the change trend of the front oxygen sensor detection value does not conform to the preset change trend.

It can be seen from the above technical solutions that the embodiments of the present application have the following advantages:

In the embodiment of the present application, the engine can be controlled to resume the supply of fuel to deoxygenate the three-way catalytic converter, and then during the deoxygenation process of the three-way catalytic converter, the change trend of the detection value of the rear oxygen sensor is determined according to the detection value of the rear oxygen sensor at multiple different times. In this way, when the change trend indicates that there is an inflection point detection value in the detection value of the rear oxygen sensor at multiple different times, it can be determined that the three-way catalytic converter is removed. Since the rear oxygen sensor can monitor the oxygen content in the exhaust gas treated by the three-way catalytic converter, and the modification of the rear oxygen sensor will cause the change of the detection value of the rear oxygen sensor to be delayed, therefore, during the deoxygenation process of the three-way catalytic converter, the removal detection of the three-way catalytic converter can be performed in combination with the detection value of the rear oxygen sensor. If there is an inflection point detection value in the change trend corresponding to the detection value of the rear oxygen sensor, it can be characterized that the rear oxygen sensor has been modified and the three-way catalytic converter has been removed. This abnormal situation can be characterized, thereby achieving accurate judgment of whether the three-way catalytic converter has been removed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a flow chart of a method for detecting removal of a three-way catalytic converter provided in an embodiment of the present application;

FIG2 is a flow chart of an implementation method for determining a vehicle speed threshold provided by an embodiment of the present application;

FIG3 is a schematic diagram of the structure of a three-way catalytic converter removal detection device provided in an embodiment of the present application.

Detailed ways

As mentioned above, the inventors found in their research on the three-way catalytic converter that in order to detect whether the three-way catalytic converter has been removed artificially and to prevent the theft of precious metals, it is generally possible to determine whether the three-way catalytic converter has been removed by detecting the conversion efficiency of the three-way catalytic converter. When the conversion efficiency of the three-way catalytic converter decreases, it is determined that the three-way catalytic converter has been removed. However, in the case where the three-way catalytic converter is removed, if the rear oxygen sensor is modified, that is, a cavity is added to the rear oxygen sensor, then the conversion efficiency of the three-way catalytic converter detected thereafter may be similar to the conversion efficiency when the three-way catalytic converter is installed, resulting in an inability to effectively and accurately determine whether the three-way catalytic converter has been removed.

In order to solve the above problems, the embodiment of the present application provides a method for detecting the removal of a three-way catalytic converter. The method may include: first controlling the engine to resume supplying fuel to deoxygenate the three-way catalytic converter, and then during the deoxygenation process of the three-way catalytic converter, determining the change trend of the rear oxygen sensor detection value according to the rear oxygen sensor detection values at multiple different times. In this way, when the change trend indicates that there is an inflection point detection value in the rear oxygen sensor detection values at multiple different times, it can be determined that the three-way catalytic converter has been removed.

Since the rear oxygen sensor can monitor the oxygen content in the exhaust gas after being treated by the three-way catalytic converter, and the modification of the rear oxygen sensor will cause a delay in the change of the rear oxygen sensor detection value, the three-way catalytic converter removal detection can be performed in combination with the rear oxygen sensor detection value. If there is an inflection point detection value in the change trend corresponding to the rear oxygen sensor detection value, it can indicate that the rear oxygen sensor has been modified and the three-way catalytic converter has been removed, thereby achieving accurate judgment on whether the three-way catalytic converter has been removed.

In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

FIG1 is a flow chart of a method for detecting removal of a three-way catalytic converter provided in an embodiment of the present application.

As shown in FIG. 1 , the removal detection method of the three-way catalytic converter provided in the embodiment of the present application may include:

S101: Control the engine to resume fuel supply to deoxygenate the three-way catalytic converter.

In an embodiment of the present application, before controlling the engine to resume fuel supply, the engine can be controlled to enter a reverse towing condition to store oxygen in the three-way catalytic converter until the front oxygen sensor detection value is equal to the preset front oxygen sensor detection value. The reverse towing condition refers to a condition in which the vehicle engine has no power demand when running on downhill, gliding and other road conditions. When the engine enters the reverse towing condition, the engine does not spray fuel and there is no combustion in the engine cylinder. Therefore, air can enter the exhaust pipe, allowing the catalyst in the three-way catalytic converter to absorb oxygen and complete oxygen storage. Generally speaking, when the oxygen in the three-way catalytic converter is in a saturated state, the front oxygen sensor detection value can reach the preset front oxygen sensor detection value, for example, the front oxygen sensor λ value (excess air coefficient) can be equal to the preset front oxygen sensor λ value of 16.

When controlling the engine to resume fuel supply, the oxygen in the three-way catalytic converter can be removed first, and the change in the detection value of the rear oxygen sensor can be detected during the deoxygenation process, so as to complete the removal detection of the three-way catalytic converter during the deoxygenation process of the three-way catalytic converter. This can accurately and effectively determine whether the three-way catalytic converter has been removed without affecting the normal operation of the engine.

S102: During the deoxygenation process of the three-way catalytic converter, determining a change trend of the rear oxygen sensor detection value according to the rear oxygen sensor detection values at multiple different moments.

Here, the rear oxygen sensor detection value can be reflected as the rear oxygen voltage. The present application embodiment does not specifically limit the selection conditions for the time of collecting the rear oxygen sensor detection value. For example, starting from the time when the front oxygen sensor detection value begins to decrease, the rear oxygen sensor detection values at 5 different times can be collected at random until the rear oxygen sensor detection value is greater than or equal to the preset rear oxygen sensor detection value.

In addition, the embodiment of the present application may not specifically limit the process of determining the change trend of the rear oxygen sensor detection value. For ease of understanding, the embodiment of the present application may provide multiple possible implementations for illustration.

In a possible implementation, the rear oxygen sensor detection values at multiple different times can be converted into a change trend of the rear oxygen sensor detection value by drawing a trend graph. The trend graph can be embodied as one or more of a line graph, a curve graph, and a bar graph. In the line graph and the curve graph, the rise or fall of the line and the curve can represent the increase or decrease of the rear oxygen sensor detection value at multiple different times; in the bar graph, the length of the column is used to represent the increase or decrease of the rear oxygen sensor detection value at multiple different times. In this way, the change trend of the rear oxygen sensor detection value can be obtained more intuitively and clearly, which helps to conveniently determine whether the three-way catalytic converter has been removed later.

In another possible implementation, the change trend of the rear oxygen sensor detection value can be obtained by analyzing the average value of the rear oxygen sensor detection value at multiple different times. In this way, there is no need to draw a trend chart, which helps to reduce the complexity of the removal detection of the three-way catalytic converter. For technical details, please refer to the introduction below.

In addition, in order to improve the accuracy of the rear oxygen sensor detection value, and thus accurately and effectively determine whether the three-way catalytic converter has been removed, the rear oxygen sensor detection value may be stopped from being collected when the rear oxygen sensor detection value is greater than or equal to the preset rear oxygen sensor detection value, and/or the change trend of the front oxygen sensor detection value does not conform to the preset change trend. Since the rear oxygen sensor detection value is greater than or equal to the preset rear oxygen sensor detection value, and the change trend of the front oxygen sensor detection value does not conform to the preset change trend, these two situations may affect the change trend of the rear oxygen sensor detection value. Therefore, when the above two situations occur, the rear oxygen sensor detection value may be stopped from being collected. Furthermore, if the above two situations occur, after determining the change trend of the rear oxygen sensor detection value, the rear oxygen sensor detection values collected at multiple different times may be cleared.

S103: When the variation trend indicates that there is an inflection point detection value in the rear oxygen sensor detection values at a plurality of different moments, it is determined that the three-way catalyst is removed.

For the case where a three-way catalytic converter is installed, when the engine resumes fuel supply to deoxygenate the three-way catalytic converter, the change in the rear oxygen sensor detection value will show a steady upward trend. For the case where the three-way catalytic converter is removed and a cavity is added to the rear oxygen sensor, when the engine resumes fuel supply to deoxygenate the three-way catalytic converter, the change in the rear oxygen sensor detection value will be delayed and rise instantly after the delay, showing a fluctuating upward trend. It can be seen that if there are inflection point detection values in the rear oxygen sensor detection values at multiple different times, it can indicate that the rear oxygen sensor has been modified and the three-way catalytic converter has been removed, which is an abnormal situation, so as to accurately judge whether the three-way catalytic converter has been removed.

Combined with the above S101-S103 related content, it can be known that in the embodiment of the present application, the engine can be controlled to resume the supply of fuel to deoxygenate the three-way catalytic converter, and then in the process of deoxygenating the three-way catalytic converter, the change trend of the detection value of the rear oxygen sensor is determined according to the detection value of the rear oxygen sensor at multiple different times. In this way, when the change trend indicates that there is an inflection point detection value in the detection value of the rear oxygen sensor at multiple different times, it can be determined that the three-way catalytic converter is removed. Since the rear oxygen sensor can monitor the oxygen content in the exhaust gas treated by the three-way catalytic converter, and the modification of the rear oxygen sensor will cause the change of the detection value of the rear oxygen sensor to be delayed, therefore, in the process of deoxygenating the three-way catalytic converter, the removal detection of the three-way catalytic converter can be performed in combination with the detection value of the rear oxygen sensor. If there is an inflection point detection value in the change trend corresponding to the detection value of the rear oxygen sensor, it can be characterized that the rear oxygen sensor has been modified and the three-way catalytic converter has been removed. This abnormal situation can be achieved, thereby accurately judging whether the three-way catalytic converter has been removed.

In order to conveniently determine whether the three-way catalytic converter is removed and reduce the complexity of the removal detection of the three-way catalytic converter, the embodiment of the present application can provide a possible implementation method for determining the change trend of the rear oxygen sensor detection value, which can specifically include S201-S202. S201 and S202 are described below in conjunction with the embodiments and the accompanying drawings.

FIG2 is a flow chart of an implementation method for determining a vehicle speed threshold provided by an embodiment of the present application. As shown in FIG2 , S201-S202 may specifically include:

S201: Determine an average value of the rear oxygen sensor detection values at a plurality of different moments according to the rear oxygen sensor detection values at a plurality of different moments.

S202: Determine a change trend based on the average value and a preset reference average value when the three-way catalytic converter is not removed.

The embodiments of the present application may not specifically limit the implementation method of determining the change trend. For ease of understanding, a possible implementation method is described below.

In a possible implementation, S202 may specifically include: when the average value matches the preset reference average value, determining the change trend as a steady upward trend; when the average value does not match the preset reference average value, determining the change trend as a fluctuating upward trend. The steady upward trend is used to indicate that there is no inflection point detection value in the detection values of the rear oxygen sensor at multiple different times; the fluctuating upward trend is used to indicate that there is an inflection point detection value in the detection values of the rear oxygen sensor at multiple different times. In addition, the average value matches the preset reference average value, which can be reflected in that the average value is equal to the preset reference average value, or that there is a negligible error between the average value and the preset reference average value; the average value does not match the preset reference average value, which can be reflected in that the difference between the average value and the preset average value is large. Since a preset reference average value when the three-way catalytic converter is not removed is preset, when the actual average value matches the preset reference average value, it can be considered that there is no inflection point detection value in the detection values of the rear oxygen sensor at multiple different times, that is, the detection trend of the detection value of the rear oxygen sensor is a steady upward trend. When the average value does not match the preset reference average value, it can be considered that there is an inflection point detection value in the detection values of the rear oxygen sensor at multiple different times, that is, the detection trend of the detection value of the rear oxygen sensor is a fluctuating upward trend.

In combination with the relevant contents of S201-S202 above, it can be known that in the embodiment of the present application, by using the average value of the rear oxygen sensor detection values at multiple different times and the preset benchmark average value when the three-way catalytic converter is not removed, it is possible to easily determine whether the three-way catalytic converter has been removed, and there is no need to draw a trend graph, thereby reducing the complexity of the three-way catalytic converter removal detection.

Based on the removal detection method of the three-way catalytic converter provided in the above embodiment, the present application embodiment further provides a removal detection device for the three-way catalytic converter. The removal detection device for the three-way catalytic converter is described below in conjunction with the embodiments and drawings.

FIG3 is a schematic diagram of the structure of a three-way catalytic converter removal detection device provided in an embodiment of the present application. In conjunction with FIG3 , the three-way catalytic converter removal detection device 300 provided in an embodiment of the present application may include:

The deoxygenation control module 301 is used to control the engine to resume supplying fuel so as to deoxygenate the three-way catalytic converter;

A change trend determination module 302 is used to determine a change trend of the rear oxygen sensor detection value according to the rear oxygen sensor detection values at multiple different moments during the deoxygenation process of the three-way catalytic converter;

The removal detection module 303 is used to determine that the three-way catalytic converter is removed when the variation trend indicates that there is an inflection point detection value in the rear oxygen sensor detection values at multiple different moments.

In the embodiment of the present application, through the cooperation of the deoxygenation control module 301, the change trend determination module 302 and the removal detection module 303, the removal detection of the three-way catalytic converter can be performed in combination with the detection value of the rear oxygen sensor during the deoxygenation process of the three-way catalytic converter. If there is an inflection point detection value in the change trend corresponding to the detection value of the rear oxygen sensor, it can be represented that the rear oxygen sensor has been modified and the three-way catalytic converter has been removed, thereby achieving accurate judgment on whether the three-way catalytic converter has been removed.

As an implementation manner, in order to accurately and effectively determine whether the three-way catalytic converter is removed, the change trend determination module 302 specifically includes:

A first determination module, configured to determine an average value of the rear oxygen sensor detection values at a plurality of different moments according to the rear oxygen sensor detection values at a plurality of different moments;

The second determination module is used to determine the change trend according to the average value and a preset reference average value when the three-way catalytic converter is not removed.

As an implementation manner, in order to accurately and effectively determine whether the three-way catalytic converter is removed, the second determination module is specifically configured to:

When the average value matches the preset reference average value, the change trend is determined as a steady upward trend; the steady upward trend is used to indicate that there is no inflection point detection value in the rear oxygen sensor detection values at multiple different moments;

When the average value does not match the preset reference average value, the change trend is determined as a fluctuating upward trend; the fluctuating upward trend is used to indicate that there are inflection point detection values in the rear oxygen sensor detection values at multiple different moments.

As an implementation manner, in order to accurately and effectively determine whether the three-way catalytic converter is removed, the three-way catalytic converter removal detection device 300 may further include:

The oxygen storage control module is used to control the engine to enter the reverse drag condition to store oxygen in the three-way catalytic converter until the front oxygen sensor detection value is equal to the preset front oxygen sensor detection value.

As an implementation manner, in order to accurately and effectively determine whether the three-way catalytic converter is removed, the three-way catalytic converter removal detection device 300 may further include:

The data processing module is used to stop collecting the rear oxygen sensor detection value when the rear oxygen sensor detection value is greater than or equal to the preset rear oxygen sensor detection value and/or the change trend of the front oxygen sensor detection value does not conform to the preset change trend.

The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims (8)

1. A method for detecting removal of a three-way catalytic converter, comprising: Controlling the engine to resume fuel supply to deoxygenate the three-way catalytic converter; During the deoxygenation process of the three-way catalytic converter, determining a change trend of the detection value of the rear oxygen sensor according to the detection values of the rear oxygen sensor at multiple different moments; When the variation trend indicates that there is an inflection point detection value in the plurality of rear oxygen sensor detection values at different times, determining that the three-way catalytic converter is removed; Wherein, determining the change trend of the rear oxygen sensor detection value according to the rear oxygen sensor detection values at multiple different moments includes: Determining an average value of the rear oxygen sensor detection values at the plurality of different moments according to the rear oxygen sensor detection values at the plurality of different moments; The change trend is determined according to the average value and a preset reference average value when the three-way catalytic converter is not removed. 2. The method according to claim 1, characterized in that the determining the change trend according to the average value and a preset reference average value when the three-way catalytic converter is not removed comprises: When the average value matches the preset reference average value, the change trend is determined as a steady upward trend; the steady upward trend is used to indicate that the inflection point detection value does not exist in the rear oxygen sensor detection values at the plurality of different moments; When the average value does not match the preset reference average value, the change trend is determined as a fluctuating upward trend; the fluctuating upward trend is used to indicate that the inflection point detection value exists in the rear oxygen sensor detection values at the plurality of different moments. 3. The method according to claim 1 or 2, characterized in that before controlling the engine to resume supplying fuel, the method further comprises: The engine is controlled to enter a reverse drag condition to store oxygen in the three-way catalytic converter until a front oxygen sensor detection value is equal to a preset front oxygen sensor detection value. 4. The method according to claim 1 or 2, characterized in that the method further comprises: When the rear oxygen sensor detection value is greater than or equal to a preset rear oxygen sensor detection value, and/or the change trend of the front oxygen sensor detection value does not conform to a preset change trend, the collection of the rear oxygen sensor detection value is stopped. 5. A three-way catalytic converter removal detection device, characterized in that it comprises: A deoxygenation control module, used for controlling the engine to resume supplying fuel so as to deoxygenate the three-way catalytic converter; A variation trend determination module, used for determining, during the deoxygenation process of the three-way catalytic converter, a variation trend of the detection value of the rear oxygen sensor according to the detection values of the rear oxygen sensor at multiple different moments; a removal detection module, configured to determine that the three-way catalytic converter is removed when the change trend indicates that there is an inflection point detection value in the rear oxygen sensor detection values at the plurality of different moments; The change trend determination module specifically includes: A first determining module, configured to determine an average value of the rear oxygen sensor detection values at the plurality of different moments according to the rear oxygen sensor detection values at the plurality of different moments; The second determination module is used to determine the change trend according to the average value and a preset reference average value when the three-way catalytic converter is not removed. 6. The device according to claim 5, characterized in that the second determining module is specifically used to: When the average value matches the preset reference average value, the change trend is determined as a steady upward trend; the steady upward trend is used to indicate that the inflection point detection value does not exist in the rear oxygen sensor detection values at the plurality of different moments; When the average value does not match the preset reference average value, the change trend is determined as a fluctuating upward trend; the fluctuating upward trend is used to indicate that the inflection point detection value exists in the rear oxygen sensor detection values at the plurality of different moments. 7. The device according to claim 5 or 6, characterized in that the device further comprises: The oxygen storage control module is used to control the engine to enter a reverse drag condition so as to store oxygen in the three-way catalytic converter until the front oxygen sensor detection value is equal to a preset front oxygen sensor detection value. 8. The device according to claim 5 or 6, characterized in that the device further comprises: The data processing module is used to stop collecting the detection value of the rear oxygen sensor when the detection value of the rear oxygen sensor is greater than or equal to a preset detection value of the rear oxygen sensor and/or the change trend of the detection value of the front oxygen sensor does not conform to the preset change trend.