阅读说明：本技术 一种诊断柴油机废气净化系统故障的试验方法 (Test method for diagnosing faults of exhaust gas purification system of diesel engine ) 是由 陈旭 柴启寅 刘凤阳 缪斯浩 陈猛 程凯 张导龑 于 2020-06-24 设计创作，主要内容包括：本申请涉及一种诊断柴油机废气净化系统故障的试验方法,属于发动机尾气后处理技术领域,该方法包括：将喷油嘴在氧化型催化器上游的排气通道内取出并放入容器内；启动柴油机控制喷油嘴向容器内喷射柴油；OBD系统监测氧化型催化器的物理量并上传至ECU电控单元；ECU电控单元诊断氧化型催化器的物理量超出设定阈值范围,并对氧化型催化器效率低故障报出；将喷油嘴安装在氧化型催化器上游的排气通道内；启动柴油机控制喷油嘴向排气通道内喷射柴油；OBD系统监测氧化型催化器的物理量并上传至ECU电控单元；ECU电控单元诊断氧化型催化器的物理量在设定阈值范围,并退出氧化型催化器效率低故障。本申请无需更换氧化型催化器样件,提高了试验效率。(The application relates to a test method for diagnosing faults of a diesel engine exhaust gas purification system, which belongs to the technical field of engine exhaust gas aftertreatment and comprises the following steps: taking out the oil nozzle from the exhaust passage at the upstream of the oxidation type catalytic converter and placing the oil nozzle into a container; starting a diesel engine to control an oil nozzle to spray diesel oil into the container; the OBD system monitors the physical quantity of the oxidation type catalyst and uploads the physical quantity to the ECU; the ECU diagnoses that the physical quantity of the oxidation type catalytic converter exceeds a set threshold range, and reports the low-efficiency fault of the oxidation type catalytic converter; installing an oil nozzle in an exhaust passage upstream of the oxidation catalyst; starting a diesel engine to control an oil nozzle to spray diesel oil into an exhaust passage; the OBD system monitors the physical quantity of the oxidation type catalyst and uploads the physical quantity to the ECU; and the ECU diagnoses that the physical quantity of the oxidation type catalyst is in a set threshold range, and exits the low-efficiency fault of the oxidation type catalyst. This application need not to change oxidation type catalytic converter appearance piece, has improved test efficiency.)

1. A test method for diagnosing a fault in an exhaust gas purification system of a diesel engine, the method comprising:

taking out the oil nozzle (2) from the exhaust passage (3) at the upstream of the oxidation type catalytic converter (4) and placing the oil nozzle into a container (10);

starting the diesel engine (1) to control the fuel injection nozzle (2) to inject diesel into the container (10) so as to store the diesel in the container (10);

the OBD system (5) monitors the physical quantity of the oxidation catalyst (4) and uploads the physical quantity to an ECU (electronic control unit) (6);

the ECU (6) diagnoses that the physical quantity of the oxidation type catalytic converter (4) exceeds a set threshold range, and reports the low-efficiency fault of the oxidation type catalytic converter (4);

installing an oil nozzle (2) in an exhaust passage (3) at the upstream of an oxidation type catalytic converter (4);

the diesel engine (1) is started again to control the oil nozzle (2) to inject diesel oil into the exhaust passage (3), so that the diesel oil is combusted in the oxidation type catalyst (4);

the OBD system (5) monitors the physical quantity of the oxidation catalyst (4) again and uploads the physical quantity to the ECU (6);

and the ECU (6) diagnoses that the physical quantity of the oxidation catalyst (4) is in a set threshold range, and exits the low-efficiency fault of the oxidation catalyst (4).

2. A test method for diagnosing a malfunction of an exhaust gas purification system for a diesel engine according to claim 1, wherein:

the diagnostic working condition is that the upstream temperature of the oxidation type catalytic converter (4) is 200-600 ℃.

3. A test method for diagnosing a malfunction of an exhaust gas purification system for a diesel engine according to claim 1, wherein:

the physical quantities of the oxidation catalyst (4) are:

calculating the calorific value Q1 of diesel oil according to the diesel oil flow injected by the oil injection nozzle (2);

calculating the calorific value Q2 increased by the oxidation catalyst (4) according to the temperatures of the upstream and downstream of the oxidation catalyst (4);

the conversion efficiency eta of the oxidation catalyst (4) is calculated according to the added calorific value Q2 of the oxidation catalyst (4) and the calorific value Q1 of the diesel oil.

4. A test method for diagnosing a malfunction of an exhaust gas purification system for a diesel engine according to claim 3, wherein:

the calorific value Q1 of diesel oil is calculated according to the diesel oil flow injected by the oil injection nozzle (2);

in the formula:

m is the mass of the diesel oil;

q is the heat value of the diesel oil of 12 kwh/kg;

the calorific value Q2 increased by the oxidation catalyst (4) is M C (T2-T1);

in the formula:

m is the mass of exhaust gas passing through the oxidation catalyst (4);

c is the specific heat capacity of exhaust gas;

t2 is the temperature downstream of the oxidation catalyst (4);

t1 is the temperature upstream of the oxidation catalyst (4);

the conversion efficiency η of the oxidation catalyst (4) is Q2/Q1.

5. A test method for diagnosing a malfunction of an exhaust gas purification system for a diesel engine according to claim 1, wherein:

a first temperature sensor (7) and a second temperature sensor (8) are respectively arranged at the upstream and downstream of the oxidation type catalytic converter (4), and the first temperature sensor (7) and the second temperature sensor (8) are both connected with the OBD system (5);

the first temperature sensor (7) is used for detecting the temperature at the upstream of the oxidation catalyst (4), and the second temperature sensor (8) is used for detecting the temperature at the downstream of the oxidation catalyst (4).

6. A test method for diagnosing a malfunction of an exhaust gas purification system for a diesel engine according to claim 1, wherein:

the diesel engine (1) is equipped with flowmeter (9), and flowmeter (9) are used for measuring the diesel oil flow, flowmeter (9) are connected with OBD system (5).

7. A test method for diagnosing a malfunction of an exhaust gas purification system for a diesel engine according to claim 1, wherein:

the inlet of the container (10) is larger than 1mm, and the height of the container (10) is larger than 10 mm.

8. A test method for diagnosing a malfunction of an exhaust gas purification system for a diesel engine according to claim 1, wherein:

the oil nozzle (2) is detachably connected with the exhaust channel (3) through threads.

9. A test method for diagnosing a malfunction of an exhaust gas purification system for a diesel engine according to claim 1, wherein:

the downstream of the oxidation type catalyst (4) is also sequentially communicated with a diesel particle catcher, an SCR catalyst and an ammonia gas catcher;

the diesel particulate filter is used for filtering PM particles, the SCR catalyst is used for filtering nitrogen oxides, and the ammonia gas catcher is used for filtering ammonia gas.

Technical Field

The application relates to the technical field of engine tail gas aftertreatment, in particular to a test method for diagnosing faults of a diesel engine exhaust gas purification system.

Background

Automobile exhaust emission has become a main atmospheric pollution source, and in order to reduce the influence of automobile exhaust on the environment, exhaust emitted by an engine sequentially passes through a DOC (Diesel oxidation Catalyst), a DPF (Diesel particulate Filter) and a SCR (Selective Catalytic Reduction) Catalyst and then is emitted into the atmosphere, so that the influence of automobile exhaust on the environment is reduced. The DOC is placed in front of the DPF and the SCR catalyst and used for converting carbon monoxide (CO) and Hydrocarbon (HC) in exhaust gas into harmless water (H20) and carbon dioxide (CO2), oxidizing Nitric Oxide (NO) in exhaust gas into nitrogen dioxide (NO2), accelerating the conversion speed and efficiency of subsequent SCR on nitrogen oxide (NOx), catalytically oxidizing fuel injected in front of the DOC, and raising the temperature in the DOC through combustion of the fuel, so that early preparation is made for DPF regeneration.

In order to meet the tail gas emission requirements of the national six-diesel engine, diesel engine manufacturers develop the national six-diesel engine, and the national six-diesel engine is matched with a post-treatment system of a Diesel Oxidation Catalyst (DOC) + a Diesel Particulate Filter (DPF) + a selective oxidation reduction device (SCR) in order to reduce NOx and particle emission in the tail gas of an engine.

According to the tail gas emission requirements of the national six-diesel engine, the DOC efficiency fault can be reported when the DOC efficiency is low, and the DOC efficiency fault can be quitted when the DOC efficiency is normal. In the related technology, a degraded sample piece without being coated with a DOC catalyst is prepared to verify DOC inefficiency fault report, and a post-treatment sample piece coated with the DOC catalyst is adopted to verify DOC inefficiency fault quitting.

Disclosure of Invention

The embodiment of the application provides a test method for diagnosing faults of a diesel engine exhaust gas purification system, and aims to solve the problems that in the related technology, special degradation samples and qualified samples need to be prepared for verifying DOC low-efficiency fault reporting and DOC normal reporting, and the DOC low-efficiency fault reporting and the DOC normal reporting are realized by replacing the samples in the verification process, so that the test efficiency is influenced.

The embodiment of the application provides a test method for diagnosing faults of an exhaust gas purification system of a diesel engine, which comprises the following steps:

taking out the oil nozzle from the exhaust passage at the upstream of the oxidation type catalytic converter and placing the oil nozzle into a container;

starting a diesel engine to control an oil nozzle to inject diesel oil into a container so that the diesel oil is stored in the container;

the OBD system monitors the physical quantity of the oxidation type catalyst and uploads the physical quantity to the ECU;

the ECU diagnoses that the physical quantity of the oxidation type catalytic converter exceeds a set threshold range, and reports the low-efficiency fault of the oxidation type catalytic converter;

installing an oil nozzle in an exhaust passage upstream of the oxidation catalyst;

starting the diesel engine to control the oil injection nozzle to inject diesel oil into the exhaust channel again so as to enable the diesel oil to be combusted in the oxidation type catalyst;

the OBD system monitors the physical quantity of the oxidation type catalyst again and uploads the physical quantity to the ECU;

and the ECU diagnoses that the physical quantity of the oxidation type catalyst is in a set threshold range, and exits the low-efficiency fault of the oxidation type catalyst.

In some embodiments: the diagnostic working condition is that the upstream temperature of the oxidation type catalyst is 200-600 ℃.

In some embodiments: the physical quantities of the oxidation catalyst are:

calculating the calorific value Q1 of diesel according to the diesel flow injected by the oil injection nozzle;

calculating the calorific value Q2 of the increase of the oxidation catalyst according to the temperatures of the upstream and downstream of the oxidation catalyst;

the conversion efficiency eta of the oxidation catalyst is calculated according to the calorific value Q2 added by the oxidation catalyst and the calorific value Q1 of diesel oil.

In some embodiments: calculating the calorific value Q1 ═ m × Q of diesel oil according to the diesel oil flow injected by the oil injection nozzle;

in the formula:

m is the mass of the diesel oil;

q is the heat value of the diesel oil of 12 kwh/kg;

the oxidation catalyst has an increased calorific value of Q2 ═ M × C (T2-T1);

in the formula:

m is the mass of exhaust passing through the oxidation catalyst;

c is the specific heat capacity of exhaust gas;

t2 is the temperature downstream of the oxidation catalyst;

t1 is the temperature upstream of the oxidation catalyst;

the conversion efficiency η of the oxidation catalyst is Q2/Q1.

In some embodiments: a first temperature sensor and a second temperature sensor are respectively arranged at the upstream and downstream of the oxidation type catalytic converter, and both the first temperature sensor and the second temperature sensor are connected with an OBD system;

the first temperature sensor is used for detecting the temperature at the upstream of the oxidation catalyst, and the second temperature sensor is used for detecting the temperature at the downstream of the oxidation catalyst.

In some embodiments: the diesel engine is equipped with the flowmeter, and the flowmeter is used for measuring the diesel oil flow, the flowmeter and OBD headtotail.

In some embodiments: the inlet of the vessel is greater than 1mm and the height of the vessel is greater than 10 mm.

In some embodiments: the oil nozzle is detachably connected with the exhaust channel through threads.

In some embodiments: the downstream of the oxidation type catalyst is also sequentially communicated with a diesel particle catcher, an SCR catalyst and an ammonia gas catcher;

the diesel particulate filter is used for filtering PM particles, the SCR catalyst is used for filtering nitrogen oxides, and the ammonia gas catcher is used for filtering ammonia gas.

The beneficial effect that technical scheme that this application provided brought includes:

the embodiment of the application provides a test method for diagnosing the fault of a diesel engine exhaust gas purification system, which is characterized in that an oil nozzle is taken out of an exhaust passage at the upstream of an oxidation type catalytic converter and is placed in a container; starting a diesel engine to control an oil nozzle to spray diesel oil into the container; the OBD system monitors the physical quantity of the oxidation type catalyst and uploads the physical quantity to the ECU; and the ECU diagnoses that the physical quantity of the oxidation type catalytic converter exceeds a set threshold range, and reports the low-efficiency fault of the oxidation type catalytic converter. Installing an oil nozzle in an exhaust passage upstream of the oxidation catalyst; the diesel engine is started again to control the oil injection nozzle to inject diesel oil into the exhaust channel so as to enable the diesel oil to be combusted in the oxidation type catalyst; the OBD system monitors the physical quantity of the oxidation type catalyst and uploads the physical quantity to the ECU; and the ECU diagnoses that the physical quantity of the oxidation type catalyst is in a set threshold range, and exits the low-efficiency fault of the oxidation type catalyst.

Therefore, when the testing method verifies that the efficiency of the oxidation type catalytic converter is low and the fault is reported, the oil injection nozzle is taken out from the exhaust channel at the upstream of the oxidation type catalytic converter and is placed into the container, the oil injection nozzle injects diesel oil into the container, the diesel oil is not injected into the oxidation type catalytic converter to be combusted, and the fault of the efficiency of the oxidation type catalytic converter can be reported. According to the test method, when the oxidation type catalytic converter exits from the low-efficiency fault, the oil injection nozzle is installed in the exhaust passage at the upper stream of the oxidation type catalytic converter, and the oil injection nozzle injects diesel oil into the exhaust passage so that the diesel oil is combusted in the oxidation type catalytic converter, and the low-efficiency fault of the oxidation type catalytic converter can exit. According to the method, the failure report of the oxidation type catalytic converter can be verified by disassembling the oil nozzle, the failure of exiting the oxidation type catalytic converter can be verified by installing the oil nozzle, the oxidation type catalytic converter sample does not need to be replaced, and the test efficiency is improved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic structural diagram of an embodiment of the present application;

fig. 2 is a flow chart of a method implemented by the present application.

Reference numerals:

1. a diesel engine; 2. an oil jet; 3. an exhaust passage; 4. an oxidation catalyst; 5. an OBD system; 6. an ECU electronic control unit; 7. a first temperature sensor; 8. a second temperature sensor; 9. a flow meter; 10. a container.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The embodiment of the application provides a test method for diagnosing faults of a diesel engine exhaust gas purification system, which can solve the problems that in the related technology, special degradation samples and qualified samples need to be prepared for verifying DOC low-efficiency fault reporting and DOC normal reporting, and in the verification process, the samples need to be replaced to report the oxidation catalyst low-efficiency faults and quit the oxidation catalyst low-efficiency faults, so that the test efficiency is influenced.

Referring to fig. 1 and 2, an embodiment of the present application provides a test method for diagnosing a fault of an exhaust gas purification system of a diesel engine, the method including the steps of:

s1, the fuel injection nozzle 2 is taken out of the exhaust passage 3 upstream of the oxidation catalyst 4 and placed in the container 10.

S2, starting the diesel engine 1, controlling the oil injection nozzle 2 to inject diesel oil into the container 10 when the diesel engine 1 is in a thermal WHTC circulation working condition and the upstream temperature of the oxidation type catalytic converter is 200-600 ℃ so as to enable the diesel oil to be stored in the container 10, wherein the inlet of the container 10 is larger than 1mm, the height of the container 10 is larger than 10mm, and the diesel oil is prevented from being directly discharged into the atmosphere and having fire risk and environmental pollution hazards.

S3, the OBD system 5 monitors the physical quantity of the oxidation catalyst 4 and uploads it to the ECU 6.

S4, the ECU 6 diagnoses that the physical quantity of the oxidation catalyst 4 exceeds the set threshold range, and reports the low efficiency fault of the oxidation catalyst.

S5, the oil nozzle 2 is installed in the exhaust channel 3 at the upstream of the oxidation type catalytic converter 4, and the oil nozzle 2 is detachably connected with the exhaust channel 3 through threads.

And S6, starting the diesel engine 1 again, controlling the oil nozzle 2 to inject diesel oil into the exhaust channel 3 when the diesel engine 1 is in a hot WHTC circulation working condition and the upstream temperature of the oxidation catalyst is 200-600 ℃, so that the diesel oil is combusted in the oxidation catalyst 4.

S7, the OBD system 5 again monitors the physical quantity of the oxidation catalyst 4 and uploads it to the ECU 6.

S8, the ECU 6 diagnoses that the physical quantity of the oxidation catalyst 4 is in the set threshold range, and exits the low-efficiency fault of the oxidation catalyst.

According to the test method, when the fault of low efficiency of the oxidation type catalyst is reported, the oil nozzle 2 is taken out of the exhaust channel 3 at the upstream of the oxidation type catalyst 4 and placed into the container 10, then the diesel engine 1 is started, the oil nozzle 2 is controlled to spray diesel oil into the container 10 under the working condition that the diesel engine 1 is in a hot WHTC cycle, so that the diesel oil is stored in the container 10, and no diesel oil is sprayed into the oxidation type catalyst 4 to be combusted, therefore, the temperature difference of the upstream and downstream of the oxidation type catalyst 4 is small, the oxidation efficiency of the oxidation type catalyst 4 is calculated according to the temperature of the upstream and downstream of the oxidation type catalyst 4 and the fuel quantity heat value of the diesel oil sprayed into an exhaust pipe, the oxidation efficiency of the oxidation type catalyst 4 is low, and the fault of the low efficiency of the oxidation type catalyst can be reported by the ECU 6.

According to the test method, when the fault that the oxidation type catalyst exits due to low efficiency is verified, the oil nozzle 2 is installed in the exhaust channel 3 at the upper stream of the oxidation type catalyst 4, then the diesel engine 1 is started, the oil nozzle 2 is controlled to spray diesel oil into the exhaust channel 3 under the working condition that the diesel engine 1 is in a hot WHTC circulation state, so that the diesel oil is oxidized and combusted in the oxidation type catalyst 4, the downstream temperature of the oxidation type catalyst 4 is greatly increased compared with the upstream temperature of the oxidation type catalyst 4, the oxidation efficiency of the oxidation type catalyst 4 is calculated according to the upstream and downstream temperatures of the oxidation type catalyst 4 and the fuel quantity heat value sprayed into the exhaust channel 3, the oxidation efficiency of the oxidation type catalyst is very high, and the fault that the oxidation type catalyst exits due to low efficiency can be realized by the ECU 6.

According to the method, the failure report of the low efficiency of the oxidation type catalyst can be verified by disassembling the oil nozzle 2, the failure of exiting the low efficiency of the oxidation type catalyst can be verified by installing the oil nozzle 2, the sample piece of the oxidation type catalyst does not need to be replaced, the test efficiency is improved, and the research and development test progress of the automobile is improved.

In some alternative embodiments: the embodiment of the application provides a test method for diagnosing the fault of a diesel engine exhaust gas purification system, and the physical quantity of an oxidation type catalyst of the method is as follows: calculating the calorific value Q1 of diesel according to the diesel flow injected by the oil injection nozzle; calculating the calorific value Q2 of the increase of the oxidation catalyst according to the temperatures of the upstream and downstream of the oxidation catalyst; the conversion efficiency eta of the oxidation catalyst is calculated according to the calorific value Q2 added by the oxidation catalyst and the calorific value Q1 of diesel oil.

Calculating the calorific value Q1 of diesel oil according to the diesel oil flow injected by the oil injection nozzle;

in the formula: m is the mass of the diesel oil; q is the heat value of the diesel oil of 12 kwh/kg.

The oxidation catalyst added calorific value Q2 ═ M × C (T2-T1);

in the formula: m is the mass of exhaust passing through the oxidation catalyst; c is exhaust specific heat capacity, and the exhaust specific heat capacity is 1-2 kJ/(kg K); t2 is the temperature downstream of the oxidation catalyst; t1 is the temperature upstream of the oxidation catalyst;

the conversion efficiency η of the oxidation catalyst is Q2/Q1.

In some alternative embodiments: referring to fig. 1, the embodiment of the present application provides a test method for diagnosing a fault of an exhaust gas purification system of a diesel engine, in which a first temperature sensor 7 and a second temperature sensor 8 are respectively arranged upstream and downstream of an oxidation catalyst 4, and both the first temperature sensor 7 and the second temperature sensor 8 are connected with an OBD system. The first temperature sensor 7 is used to detect the temperature upstream of the oxidation catalyst 4 and the second temperature sensor 8 is used to detect the temperature downstream of the oxidation catalyst 4. The diesel engine 1 is provided with a flowmeter 9, the flowmeter 9 is used for measuring the flow of diesel oil sprayed into the exhaust channel 3 by the oil nozzle 2, the flowmeter 9 is connected with the OBD system 5, the flowmeter 9 can measure the flow of diesel oil sprayed into the exhaust channel 3 by the oil nozzle 2 and convert the flow into a heat value, and the oxidation efficiency of the oxidation catalyst 4 can be obtained by comparing the heat value generated by the flow of the diesel oil with the actual heat value generated by the oxidation combustion of the oxidation catalyst 4.

When the testing method verifies that the fault of the low efficiency of the oxidation type catalytic converter is reported, the diesel oil is not sprayed into the oxidation type catalytic converter 4 to burn, so that the temperature difference of the upstream and downstream of the oxidation type catalytic converter 4 is very small, the oxidation efficiency of the oxidation type catalytic converter 4 is calculated according to the temperature of the upstream and downstream of the oxidation type catalytic converter 4 and the fuel quantity heat value of the diesel oil sprayed into the exhaust pipe, and the fault report of the low efficiency of the oxidation type catalytic converter can be verified.

According to the test method, when the fault that the oxidation type catalytic converter exits in low efficiency is verified, diesel oil is oxidized and combusted in the oxidation type catalytic converter 4, the temperature of the downstream of the oxidation type catalytic converter 4 is greatly increased compared with the temperature of the upstream of the oxidation type catalytic converter 4, the oxidation efficiency of the oxidation type catalytic converter 4 is calculated according to the temperature of the upstream and downstream of the oxidation type catalytic converter 4 and the calorific value of the fuel quantity sprayed into the exhaust channel 3, and the fault that the oxidation type catalytic converter exits in low efficiency can be verified.

In some alternative embodiments: the downstream of the oxidation catalyst 4 is also communicated with a diesel particulate filter, an SCR catalyst and an ammonia gas catcher in sequence; the diesel particle trap is used for filtering PM particles, the SCR catalyst is used for filtering nitrogen oxides, and the ammonia gas trap is used for filtering ammonia gas. A pressure sensor is arranged in the diesel particle catcher and used for detecting the gas pressure in the diesel particle catcher.

Principle of operation

The embodiment of the application provides a test method for diagnosing the fault of a diesel engine exhaust gas purification system, and the method is characterized in that when the method verifies that the efficiency of an oxidation type catalytic converter is low and the fault is reported, an oil nozzle 2 is taken out from an exhaust passage 3 at the upstream of the oxidation type catalytic converter 4 and is placed into a container 10; starting the diesel engine 1 to control the oil nozzle 2 to inject diesel oil into the container 10 so as to store the diesel oil in the container 10; the OBD system 5 monitors the physical quantity of the oxidation catalyst 4 and uploads the physical quantity to the ECU 6; and the ECU 6 diagnoses that the physical quantity of the oxidation catalyst 4 exceeds a set threshold range, and the ECU 6 reports the low-efficiency fault of the oxidation catalyst.

When the fault that the oxidation type catalytic converter is quitted and the efficiency is low is verified, the oil nozzle 2 is arranged in the exhaust passage 3 at the upstream of the oxidation type catalytic converter 4; starting the diesel engine 1 to control the oil nozzle 2 to inject diesel oil into the exhaust passage 3 so as to enable the diesel oil to be combusted in the oxidation type catalyst 4; the OBD system 5 monitors the physical quantity of the oxidation catalyst 4 and uploads the physical quantity to the ECU 6; the ECU 6 diagnoses that the physical quantity of the oxidation catalyst 4 is in a set threshold range, and the ECU 6 exits the low-efficiency fault of the oxidation catalyst.

Therefore, when the testing method of the application verifies that the efficiency of the oxidation type catalytic converter is low and the fault is reported, the oil nozzle 2 is taken out of the exhaust channel 3 at the upstream of the oxidation type catalytic converter 4 and is placed into the container 10, the oil nozzle 2 sprays diesel oil into the container 10, the diesel oil cannot be sprayed into the oxidation type catalytic converter 4 to be combusted, and the efficiency of the oxidation type catalytic converter can be reported. According to the test method, when the fault that the oxidation type catalytic converter exits from the low efficiency is verified, the oil spray nozzle 2 is installed in the exhaust passage 3 at the upper stream of the oxidation type catalytic converter 4, and the oil spray nozzle 2 sprays diesel oil into the exhaust passage 3, so that the diesel oil is combusted in the oxidation type catalytic converter 4, and the fault that the oxidation type catalytic converter exits from the low efficiency is realized. According to the method, the failure report of the oxidation type catalytic converter 4 with low efficiency can be verified by disassembling the oil nozzle 2, the failure of the oxidation type catalytic converter exiting from low efficiency can be verified by installing the oil nozzle 2, the oxidation type catalytic converter sample does not need to be replaced, and the test efficiency is improved.

In the description of the present application, it should be noted that the terms "upper", "lower", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, which are only for convenience in describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and operate, and thus, should not be construed as limiting the present application. Unless expressly stated or limited otherwise, the terms "mounted," "connected," and "connected" are intended to be inclusive and mean, for example, that they may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

It is noted that, in the present application, relational terms such as "first" and "second", and the like, are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The above description is merely exemplary of the present application and is presented to enable those skilled in the art to understand and practice the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.