CN107542558A - Catalyst converter diagnosed system and method - Google Patents
Catalyst converter diagnosed system and method Download PDFInfo
- Publication number
- CN107542558A CN107542558A CN201610482005.1A CN201610482005A CN107542558A CN 107542558 A CN107542558 A CN 107542558A CN 201610482005 A CN201610482005 A CN 201610482005A CN 107542558 A CN107542558 A CN 107542558A
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- China
- Prior art keywords
- oxygen sensor
- post
- catalyst
- processing module
- time
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- 239000003054 catalyst Substances 0.000 title claims abstract description 75
- 238000000034 method Methods 0.000 title claims abstract description 25
- 239000001301 oxygen Substances 0.000 claims abstract description 74
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 74
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 43
- 238000002405 diagnostic procedure Methods 0.000 claims description 18
- 238000003745 diagnosis Methods 0.000 claims description 16
- 238000006243 chemical reaction Methods 0.000 claims description 4
- 230000014759 maintenance of location Effects 0.000 claims description 3
- 239000000203 mixture Substances 0.000 abstract description 4
- 238000002485 combustion reaction Methods 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 4
- 239000000446 fuel Substances 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 3
- 238000000746 purification Methods 0.000 description 3
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 2
- 229910002091 carbon monoxide Inorganic materials 0.000 description 2
- 230000003197 catalytic effect Effects 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 238000011144 upstream manufacturing Methods 0.000 description 2
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000001010 compromised effect Effects 0.000 description 1
- 239000000356 contaminant Substances 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
Classifications
-
- 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
Landscapes
- Exhaust Gas After Treatment (AREA)
Abstract
The present invention relates to a kind of catalyst converter diagnosed system and method, it includes：Post oxygen sensor, it is arranged at the exhaust end downstream of catalyst converter；And processing module, it couples with post oxygen sensor.The signal using post oxygen sensor can be only needed by using the catalyst converter diagnosed system and method for the present invention, and dense dilute state of combustion mixture need not be made to change, so as to improve the control efficiency of engine and operational efficiency, reduce and discharge and reduce integral vehicle cost.
Description
Technical Field
The present invention relates to the field of vehicle catalyst diagnostics, and more particularly, to a catalyst diagnostic system and method that utilizes a signal of a post-oxygen sensor to diagnose catalyst status.
Background
A catalyst is often provided as a purification device on a vehicle in order to purify various pollutants from exhaust gas discharged from an engine (typically, a gasoline engine). These contaminants include, but are not limited to, carbon monoxide (CO), hydrocarbons (Hydrocarbon), and Nitrogen Oxides (NO)x) And the like. It is known in the art that catalysts may experience a reduction or even failure in purification or conversion efficiency with use. In the event of a reduction or failure of the catalyst efficiency, the effectiveness of the purification of the vehicle exhaust will be compromised. For this reason, the national emission standard of GB18352.5-2013 (national emission standard of V) puts more stringent requirements on catalyst diagnosis.
A common method is to detect the state of the catalyst by detecting the oxygen storage capacity of the catalyst, such as a dual oxygen sensor active detection method. Specifically, the catalyst is connected in series on the engine exhaust pipe, and two oxygen sensors, also called a front oxygen sensor and a rear oxygen sensor, are provided in the exhaust pipe upstream and downstream of the catalyst, respectively. When the engine is in a specific operating condition, an Electronic Control Unit (ECU) actively enriches and reduces combustible mixture entering the engine. In this process, the front oxygen sensor and the rear oxygen sensor measure the interval time of the rich-lean state change of the combustible mixture. This measurement process adversely affects the closed-loop control of the engine fuel because it requires a change in rich-lean condition of the combustible mixture.
It is therefore desirable to devise a catalyst diagnostic system and method that overcomes at least one of the above-referenced problems.
Disclosure of Invention
An object of the present invention is to provide a catalyst diagnostic system that may be provided without a front oxygen sensor. It is also an object of the present invention to provide a catalyst diagnostic method. The catalyst diagnostic method only needs to utilize the signal of the rear oxygen sensor.
The purpose of the invention is realized by the following technical scheme:
a catalyst diagnostic system, wherein it comprises:
a rear oxygen sensor disposed downstream of an exhaust end of the catalyst; and
a processing module coupled with the post-oxygen sensor.
In the catalyst diagnosis system, the processing module is an ECU or an electronic control unit.
A catalyst diagnostic method, wherein it comprises the steps of:
(1) judging engine stable conditions and catalyst diagnosis conditions;
(2) the processing module collects signals through the rear oxygen sensor at intervals;
(3) the processing module processes the signals collected from the rear oxygen sensor;
(4) the processing module calculates the oxygen storage capacity of the catalyst by using the processed post-oxygen sensor signal;
(5) and judging the diagnosis result.
The catalyst diagnostic method described above, wherein the processing module collects signals from the post-oxygen sensor at 15.6ms intervals.
The catalyst diagnosis method comprises the step of processing the voltage value of the signal acquired from the rear oxygen sensor by the processing module.
The catalyst diagnosis method described above, wherein the processing module processes the voltage value of the post-oxygen sensor signal acquired from the post-oxygen sensor according to the following formula:
wherein:
FT N[]a high-pass filtered value for time N;
FT N[-1]a high-pass filtered value at the time of N-1;
FT N[-2]the high-pass filtered value at the time of N-2;
the signal value of the post oxygen sensor at the time N;
the signal value of the post-oxygen sensor at the time of N-1;
the signal value of the post-oxygen sensor at the N-2 moment is obtained; and is
The time difference between two adjacent times of the serial numbers is the time interval of the processing module for acquiring signals from the rear oxygen sensor;
B1、B2、A3 andAand 2 is a filter coefficient.
In the catalyst diagnosis method, if the filtered value of the post-oxygen sensor signal in the next calculation period is smaller than the filtered value in the previous calculation period, the ECU will keep the filtered value of the post-oxygen sensor signal in the previous calculation period until the filtered value in the next calculation period is larger than the value.
The catalyst diagnostic method described above, wherein the maximum retention time is 50 calculation cycles.
The catalyst diagnostic method described above, wherein the processing module calculates the catalyst oxygen storage capacity using the following formula:
wherein,K aare conversion coefficients.
In the catalyst diagnosis method, the processing module is an ECU or an electronic control unit.
The invention has the beneficial effects that: by adopting the catalytic converter diagnosis system and method provided by the invention, the state of the catalytic converter can be judged only by utilizing the signal of the rear oxygen sensor, and the rich-lean state of the combustible mixed gas is not required to be changed, so that the control efficiency and the operation efficiency of an engine are improved, the emission is reduced, and the cost of the whole vehicle is reduced.
Drawings
The present invention will be described in further detail below with reference to the drawings and preferred embodiments, but those skilled in the art will appreciate that the drawings are only drawn for the purpose of illustrating the preferred embodiments and therefore should not be taken as limiting the scope of the invention. Furthermore, unless specifically stated otherwise, the drawings are intended to be conceptual in nature or configuration of the described objects and may be exaggerated in nature and are not necessarily drawn to scale.
FIG. 1 is a schematic diagram of a prior art catalyst diagnostic system.
FIG. 2 is a schematic diagram of one embodiment of a catalyst diagnostic system of the present invention.
FIG. 3 is a flow chart of one embodiment of a catalyst diagnostic method of the present invention.
Detailed Description
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Those skilled in the art will appreciate that the description is illustrative only, and is not to be construed as limiting the scope of the invention.
First, it should be noted that the terms top, bottom, upward, downward and the like are defined relative to the directions in the drawings, and they are relative terms, and thus can be changed according to the different positions and different practical states in which they are located. These and other directional terms should not be construed as limiting terms.
Furthermore, it should be noted that any single technical feature described or implied in the embodiments herein, or any single technical feature shown or implied in the figures, can still be combined between these technical features (or their equivalents) to obtain other embodiments of the invention not directly mentioned herein.
Moreover, in the different figures, the same reference numerals indicate the same or substantially the same components.
FIG. 1 is a schematic diagram of a prior art catalyst diagnostic system. In which the catalyst 10 is connected in series on a line 20, the gas in the line 20 moving generally in the direction indicated by arrow a. A front oxygen sensor 11 is disposed upstream of the catalyst 10, and a rear oxygen sensor 12 is disposed downstream of the catalyst 10, the front and rear oxygen sensors 11, 12 being coupled to a processing module 30 (e.g., ECU), respectively. The processing module 30 is configured to collect data from the front and rear oxygen sensors 11, 12 in order to monitor the state of the catalyst.
FIG. 2 is a schematic diagram of one embodiment of a catalyst diagnostic system of the present invention. In contrast to the prior art catalyst diagnostic system shown in FIG. 1, it eliminates the front oxygen sensor 11.
FIG. 3 is a flow chart of one embodiment of a catalyst diagnostic method of the present invention. Wherein the processing module calculates the oxygen storage capacity of the catalyst using the vibration frequency and amplitude of the signal measured by the rear oxygen sensor 12 in different states of the catalyst. Specifically, the method comprises the following diagnosis steps:
(1) judging engine stable conditions and catalyst diagnosis conditions;
(2) the ECU acquires signals through a rear oxygen sensor at intervals;
(3) the ECU processes the voltage value of the signal acquired from the rear oxygen sensor;
(4) the ECU calculates the oxygen storage capacity of the catalyst by using the processed post-oxygen sensor signal;
(5) and judging the diagnosis result.
Specifically, in a preferred embodiment of the present invention, in step (2), the ECU collects signals from the post-oxygen sensor at time intervals of 15.6 ms. In step (3), the ECU digitally high-pass filters the voltage value of the signal collected from the post-oxygen sensor according to the following formula:
wherein:
FT N[]a high-pass filtered value for time N;
FT N[-1]a high-pass filtered value at the time of N-1;
FT N[-2]the high-pass filtered value at the time of N-2;
the signal value of the post oxygen sensor at the time N;
the signal value of the post-oxygen sensor at the time of N-1;
the signal value of the post-oxygen sensor at the N-2 moment is obtained;
B1、B2、A3 andAand 2 is a filter coefficient.
It should be noted that, preferably, the time difference between two adjacent time instants is a time interval of the processing module collecting the signal from the post-oxygen sensor. In other words, in the above preferred embodiment, the time difference between time N and time N-1 is equal to the time interval between the times when the ECU collects signals from the post-oxygen sensor, e.g., 15.6 ms; the time difference between time N-1 and time N-2 is also equal to the time interval. And the high-pass filtered value at the starting instant, i.e. instant 0, is 0.
Furthermore, provision is preferably made in step (3) to avoid unpredictable factors from influencing the diagnostic result of the catalyst. Specifically, if the filtered value of the post-oxygen sensor signal of the next calculation period is less than the filtered value of the previous calculation period, the ECU will retain the filtered value of the post-oxygen sensor signal of the previous period until the filtered value of the next calculation period is greater than this value. In the preferred embodiment, the maximum retention time is 50 calculation cycles.
In step (4), the ECU integrates and converts the filtered signal of the rear oxygen sensor to obtain the oxygen storage capacity value of the catalystFN [N]The formula is as follows:
wherein,Kaare conversion coefficients.
As will be readily appreciated by those skilled in the art,B1、B2、A3、A2 andKthe value of a may be determined based on different engine and exhaust system configurations and parameters, and may also be determined by performing experimentation, data acquisition, and data processing and fitting processes.
In step (5), the ECU judges that the diagnosis result of the catalyst, such as the oxygen storage capacity of the catalyst, is normal, and then judges that the diagnosis result is passed; and if the oxygen storage capacity of the catalyst is abnormal, determining that the catalyst is invalid.
In a preferred embodiment of the present invention, the processing module 30 is an ECU. However, the processing module 30 of the present invention may be other control modules on the vehicle, such as a vehicle controller or an engine controller, etc., according to actual needs. The catalyst diagnostic method of the present invention may be implemented either in a software module in the processing module 30 or by a separate or discrete circuit module.
As will be appreciated by those skilled in the art, the catalyst diagnostic system and method of the present invention need only employ data from the rear oxygen sensor, and thus the front oxygen sensor may not be provided in the catalyst diagnostic system, thereby reducing costs. It is also understood that the catalyst diagnostic method of the present invention may be applied to existing catalyst diagnostic systems.
It will also be appreciated by those skilled in the art that the above-described catalyst diagnostic system and method does not require rich-lean switching of the engine's fuel mixer, and therefore does not affect closed-loop control of the engine fuel, thereby improving engine control and operating efficiency, reducing emissions, and reducing overall vehicle cost.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and selecting appropriate materials and using any incorporated methods. The scope of the invention is defined by the claims and encompasses other examples that occur to those skilled in the art. Such other examples are to be considered within the scope of the invention as determined by the claims, provided that they include structural elements that do not differ from the literal language of the claimed solution, or that they include equivalent structural elements with insubstantial differences from the literal language of the claimed solution.
Claims (10)
1. A catalyst diagnostic system, comprising:
a rear oxygen sensor disposed downstream of an exhaust end of the catalyst; and
a processing module coupled with the post-oxygen sensor.
2. The catalyst diagnostic system of claim 1 wherein the processing module is an ECU or an electronic control unit.
3. A catalyst diagnostic method characterized by comprising the steps of:
(1) judging engine stable conditions and catalyst diagnosis conditions;
(2) the processing module collects signals through the rear oxygen sensor at intervals;
(3) the processing module processes the signals collected from the post-oxygen sensor;
(4) the processing module calculates a catalyst oxygen storage capacity using the processed post-oxygen sensor signal;
(5) and judging the diagnosis result.
4. The catalyst diagnostic method of claim 3 wherein the processing module collects signals from the post-oxygen sensor at 15.6ms intervals.
5. The catalyst diagnostic method of claim 3, wherein the processing module processes a voltage value of the signal collected from the post-oxygen sensor.
6. The catalyst diagnostic method of claim 3 wherein the processing module processes the voltage value of the post-oxygen sensor signal collected from the post-oxygen sensor according to the following equation:
wherein:
FT N[]a high-pass filtered value for time N;
FT N[-1]a high-pass filtered value at the time of N-1;
FT N[-2]the high-pass filtered value at the time of N-2;
the signal value of the post oxygen sensor at the time N;
the signal value of the post-oxygen sensor at the time of N-1;
the signal value of the post-oxygen sensor at the N-2 moment is obtained; and is
The time difference between two adjacent moments is the time interval of the processing module for acquiring signals from the post-oxygen sensor;
B1、B2、A3 andAand 2 is a filter coefficient.
7. The catalyst diagnostic method according to claim 6, wherein if the filtered value of the post-oxygen sensor signal of the subsequent calculation period is less than the filtered value of the previous calculation period, the ECU retains the filtered value of the post-oxygen sensor signal of the previous calculation period until the filtered value of the subsequent calculation period is greater than the filtered value.
8. The catalyst diagnostic method according to claim 7, wherein the maximum retention time is 50 calculation cycles.
9. The catalyst diagnostic method of claim 7, wherein the processing module calculates a catalyst oxygen storage capacity using the following equation:
wherein,K aare conversion coefficients.
10. The catalyst diagnostic method according to any one of claims 3 to 9, wherein the processing module is an ECU or an electronic control unit.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610482005.1A CN107542558B (en) | 2016-06-28 | 2016-06-28 | Catalyst diagnostic system and method |
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| CN201610482005.1A CN107542558B (en) | 2016-06-28 | 2016-06-28 | Catalyst diagnostic system and method |
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| CN107542558B CN107542558B (en) | 2020-06-23 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112879133A (en) * | 2019-11-29 | 2021-06-01 | 北京车和家信息技术有限公司 | Catalyst diagnosis method and device and vehicle |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5372036A (en) * | 1993-11-22 | 1994-12-13 | Ford Motor Company | Exhaust leak detection |
| US6691020B2 (en) * | 2001-06-19 | 2004-02-10 | Ford Global Technologies, Llc | Method and system for optimizing purge of exhaust gas constituent stored in an emission control device |
| CN101832172A (en) * | 2010-04-23 | 2010-09-15 | 北京锐意泰克汽车电子有限公司 | Fault diagnosis method for three-way catalytic converter of automobile |
| CN105089746A (en) * | 2014-05-20 | 2015-11-25 | 现代自动车株式会社 | Exhaust gas processing apparatus and method |
| CN105673169A (en) * | 2016-01-27 | 2016-06-15 | 潍柴动力股份有限公司 | Method and device used for monitoring three-way catalyst in engine exhaust system |
-
2016
- 2016-06-28 CN CN201610482005.1A patent/CN107542558B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5372036A (en) * | 1993-11-22 | 1994-12-13 | Ford Motor Company | Exhaust leak detection |
| US6691020B2 (en) * | 2001-06-19 | 2004-02-10 | Ford Global Technologies, Llc | Method and system for optimizing purge of exhaust gas constituent stored in an emission control device |
| CN101832172A (en) * | 2010-04-23 | 2010-09-15 | 北京锐意泰克汽车电子有限公司 | Fault diagnosis method for three-way catalytic converter of automobile |
| CN105089746A (en) * | 2014-05-20 | 2015-11-25 | 现代自动车株式会社 | Exhaust gas processing apparatus and method |
| CN105673169A (en) * | 2016-01-27 | 2016-06-15 | 潍柴动力股份有限公司 | Method and device used for monitoring three-way catalyst in engine exhaust system |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112879133A (en) * | 2019-11-29 | 2021-06-01 | 北京车和家信息技术有限公司 | Catalyst diagnosis method and device and vehicle |
| CN112879133B (en) * | 2019-11-29 | 2021-11-19 | 北京车和家信息技术有限公司 | Catalyst diagnosis method and device and vehicle |
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| CN107542558B (en) | 2020-06-23 |
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