阅读说明：本技术 蒸发系统泄露诊断方法 (Evaporation system leakage diagnosis method ) 是由 李凯 迟佳男 刘发明 温敏 徐洪伟 侯金 于 2021-08-13 设计创作，主要内容包括：本发明公开了一种蒸发系统泄露诊断方法,包括：对相关部件进行故障检测；判断是否满足相关诊断条件；在相关部件正常,且满足相关诊断条件时,关闭碳罐电磁阀和碳罐通风阀；监测油箱内的油蒸汽产生率是否小于预设值,若否,则不进行诊断；若是,则通过真空度衰减测试判断蒸发系统是否泄露。本发明的蒸发系统泄露诊断方法,通过对油箱内油蒸汽的监测,避免油蒸汽产生带来的影响,避免误判；通过对油箱真空度衰减情况进行精确判别,能够有效的监测蒸发系统的气密性,避免外部因素对真空度的影响,避免误判。(The invention discloses a leakage diagnosis method for an evaporation system, which comprises the following steps: carrying out fault detection on related components; judging whether relevant diagnosis conditions are met; when the relevant parts are normal and the relevant diagnosis conditions are met, closing the carbon tank electromagnetic valve and the carbon tank ventilation valve; monitoring whether the oil vapor generation rate in the oil tank is smaller than a preset value or not, and if not, not diagnosing; if yes, judging whether the evaporation system leaks or not through a vacuum degree attenuation test. According to the leakage diagnosis method for the evaporation system, the oil vapor in the oil tank is monitored, so that the influence caused by the oil vapor is avoided, and the misjudgment is avoided; through accurately judging the vacuum degree attenuation condition of the oil tank, the air tightness of the evaporation system can be effectively monitored, the influence of external factors on the vacuum degree is avoided, and misjudgment is avoided.)

1. A method of diagnosing a leak in an evaporation system, comprising:

carrying out fault detection on related components;

judging whether relevant diagnosis conditions are met;

when the relevant parts are normal and the relevant diagnosis conditions are met, closing the carbon tank electromagnetic valve and the carbon tank ventilation valve;

monitoring whether the oil vapor generation rate in the oil tank is smaller than a preset value or not, and if not, not diagnosing;

if yes, judging whether the evaporation system leaks or not through a vacuum degree attenuation test.

2. The method for diagnosing leakage of an evaporation system according to claim 1, wherein the determining whether the evaporation system leaks or not through a vacuum degree decay test is performed when the oil vapor generation rate in the oil tank is less than a preset value, specifically comprising:

and judging whether the evaporation system leaks or not through a total attenuation test, a sectional attenuation test and a slope convex test.

3. The method for diagnosing leakage of an evaporation system according to claim 2, wherein the step of determining whether the evaporation system leaks through a total attenuation test, a segmental attenuation test and a slope convex test specifically comprises the steps of:

establishing vacuum degree and carrying out vacuum degree attenuation test;

judging whether the attenuation slope is greater than a preset value;

if so, performing attenuation subsection test and subsection slope convex test, and judging whether the attenuation subsection test and the subsection slope convex test are larger than respective set values;

if so, judging that the evaporation system has leakage, and if not, judging that the evaporation system does not have leakage;

and if the attenuation slope is not greater than the preset value, judging that the evaporation system has no leakage.

4. The evaporative system leak diagnostic method of claim 3, wherein the establishing a vacuum level and performing a vacuum level decay test specifically comprises:

closing a carbon tank vent valve, opening a carbon tank electromagnetic valve, pumping the vacuum degree of an oil tank to a preset value, and then closing the carbon tank electromagnetic valve for attenuation test;

the judging whether the attenuation slope is greater than the preset value of the attenuation slope specifically comprises:

and judging whether the total attenuation slope of the vacuum degree is greater than a preset attenuation slope value within a preset time.

5. The method for diagnosing leakage of an evaporation system according to claim 3, wherein when the attenuation slope is greater than a predetermined value, the attenuation section test and the section slope convex test are performed to determine whether the attenuation section test and the section slope convex test are greater than respective set values, specifically comprising:

carrying out a subsection attenuation test, and dividing the total attenuation preset time into a plurality of small time segments;

when the subsection attenuation test is carried out, whether the vacuum degree attenuation slope of any subsection is larger than the preset value of the subsection attenuation slope is judged;

and performing a convex test of the segmentation slope, and judging whether the difference value between the vacuum degree attenuation slope of the current segment and the vacuum degree attenuation slope of the previous segment is greater than a convex preset value of the segmentation slope.

6. The method for diagnosing leakage of an evaporation system according to claim 1, wherein the detecting of the failure of the related component specifically comprises:

after the vehicle starts to run, the relevant parts are subjected to short circuit detection and/or open circuit detection.

7. The evaporative system leak diagnostic method as defined in claim 1, wherein the associated components include a canister solenoid valve, a canister vent valve, a tank pressure sensor, and a fuel level sensor.

8. The method for diagnosing leakage of an evaporation system according to claim 1, wherein the determining whether the relevant diagnostic condition is satisfied specifically includes:

obtaining vehicle parameters;

and judging whether the acquired vehicle parameters meet preset parameter requirements or not.

9. The evaporative system leak diagnostic method of claim 8, wherein the vehicle parameters include vehicle status parameters and/or vehicle environmental parameters, the vehicle status parameters including: the cooling liquid temperature, the oil level, the rotation speed and the vehicle speed, and the vehicle environmental parameters comprise the ambient temperature and the altitude.

10. The evaporative system leak diagnostic method as defined in claim 1, further comprising:

when the evaporation system is judged to have no leakage, the fault is not reported;

and when the leakage fault of the evaporation system is judged, the diagnosis result is output through the vehicle-mounted computer and the fault is reported.

Technical Field

The invention relates to the technical field of fuel automobiles, in particular to a leakage diagnosis method for an evaporation system.

Background

With the development and progress of society, the national degree of importance for the environment is higher and higher, and the influence of automobiles on the atmosphere as a carrier using traditional energy sources is also more and more concerned. The On-Board Diagnostic System (OBD) System is required by the national six regulations to monitor the air tightness of the vaporization System and prevent fuel leakage into the atmosphere. Therefore, when the pipeline of the evaporation system has leakage, the leakage can be accurately judged.

At present, the leakage condition of a fuel pipeline in an evaporation system is monitored and diagnosed by establishing vacuum pressure, then monitoring the attenuation condition of the vacuum pressure in a closed space, and if the attenuation quantity is larger in a certain time, judging that the pipeline has leakage. Relates to a carbon tank, a carbon tank electromagnetic valve, a carbon tank ventilation valve, an oil pump, an oil level sensor, an oil tank pressure sensor and other parts. The influence of relevant factors on the vacuum degree is not considered, and the condition of inaccurate diagnosis can be caused. For example, the reduction of the vacuum degree may be a large change in the vacuum degree due to the generation of oil vapor, or may be an abnormal fluctuation in the attenuation of the vacuum degree due to the external force applied to the oil tank, thereby affecting the determination.

Therefore, a method for diagnosing leakage of an evaporation system is needed.

Disclosure of Invention

The invention aims to provide a leakage diagnosis method for an evaporation system, which aims to solve the problems in the prior art, can monitor oil gas and an attenuation process and realize omnibearing and accurate judgment.

The invention provides a leakage diagnosis method for an evaporation system, which comprises the following steps:

carrying out fault detection on related components;

judging whether relevant diagnosis conditions are met;

when the relevant parts are normal and the relevant diagnosis conditions are met, closing the carbon tank electromagnetic valve and the carbon tank ventilation valve;

monitoring whether the oil vapor generation rate in the oil tank is smaller than a preset value or not, and if not, not diagnosing;

if yes, judging whether the evaporation system leaks or not through a vacuum degree attenuation test.

The method for diagnosing leakage of an evaporation system, preferably, when the oil vapor generation rate in the oil tank is less than a preset value, determining whether the evaporation system leaks through a vacuum degree attenuation test, specifically including:

and judging whether the evaporation system leaks or not through a total attenuation test, a sectional attenuation test and a slope convex test.

The method for diagnosing leakage of an evaporation system as described above, wherein preferably, the determining whether the evaporation system leaks through a total attenuation test, a segmental attenuation test and a slope convex test specifically includes:

establishing vacuum degree and carrying out vacuum degree attenuation test;

judging whether the attenuation slope is greater than a preset value;

if so, performing attenuation subsection test and subsection slope convex test, and judging whether the attenuation subsection test and the subsection slope convex test are larger than respective set values;

if so, judging that the evaporation system has leakage, and if not, judging that the evaporation system does not have leakage;

and if the attenuation slope is not greater than the preset value, judging that the evaporation system has no leakage.

The method for diagnosing leakage of an evaporation system, wherein preferably, the establishing of the vacuum degree and the vacuum degree decay testing specifically include:

closing a carbon tank vent valve, opening a carbon tank electromagnetic valve, pumping the vacuum degree of an oil tank to a preset value, and then closing the carbon tank electromagnetic valve for attenuation test;

the judging whether the attenuation slope is greater than the preset value of the attenuation slope specifically comprises:

and judging whether the total attenuation slope of the vacuum degree is greater than a preset attenuation slope value within a preset time.

The method for diagnosing leakage of an evaporation system as described above, wherein preferably, when the attenuation slope is greater than a preset value, the attenuation section test and the section slope convex test are performed to determine whether the attenuation section test and the section slope convex test are greater than respective corresponding set values, and specifically includes:

carrying out a subsection attenuation test, and dividing the total attenuation preset time into a plurality of small time segments;

when the subsection attenuation test is carried out, whether the vacuum degree attenuation slope of any subsection is larger than the preset value of the subsection attenuation slope is judged;

and performing a convex test of the segmentation slope, and judging whether the difference value between the vacuum degree attenuation slope of the current segment and the vacuum degree attenuation slope of the previous segment is greater than a convex preset value of the segmentation slope.

The method for diagnosing leakage of an evaporation system as described above, wherein preferably, the performing fault detection on the relevant component specifically includes:

after the vehicle starts to run, the relevant parts are subjected to short circuit detection and/or open circuit detection.

The evaporation system leakage diagnosis method as described above, wherein preferably the relevant components include a canister solenoid valve, a canister vent valve, a tank pressure sensor, and a fuel level sensor.

The method for diagnosing leakage of an evaporation system as described above, wherein preferably, the determining whether the relevant diagnostic condition is satisfied includes:

obtaining vehicle parameters;

and judging whether the acquired vehicle parameters meet preset parameter requirements or not.

The evaporation system leakage diagnosis method as described above, wherein preferably, the vehicle parameter includes a vehicle state parameter and/or a vehicle environment parameter, and the vehicle state parameter includes: the cooling liquid temperature, the oil level, the rotation speed and the vehicle speed, and the vehicle environmental parameters comprise the ambient temperature and the altitude.

The method for diagnosing leakage of an evaporation system as described above, wherein preferably, the method for diagnosing leakage of an evaporation system further comprises:

when the evaporation system is judged to have no leakage, the fault is not reported;

and when the leakage fault of the evaporation system is judged, the diagnosis result is output through the vehicle-mounted computer and the fault is reported.

The invention provides a leakage diagnosis method for an evaporation system, which avoids the influence caused by oil vapor generation and avoids misjudgment by monitoring the oil vapor in an oil tank; by accurately judging the vacuum degree attenuation condition of the oil tank, the air tightness of the evaporation system can be effectively monitored, the influence of external factors on the vacuum degree is avoided, and misjudgment is avoided; when the integral attenuation degree is smaller than a set value, judging that no leakage exists, and when the integral attenuation degree is larger than the set value, carrying out a subsection attenuation test and a subsection slope convex test to ensure that the attenuation process is normal, and accurately judging the attenuation degree, thereby accurately judging the air tightness of the evaporation system and eliminating the influence of the outside on the attenuation process.

Drawings

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described with reference to the accompanying drawings, in which:

FIG. 1 is a flow chart of an embodiment of a method for diagnosing leaks in an evaporative system provided by the present invention;

fig. 2 is a schematic view of an operating principle of an embodiment of the leak diagnosis method for an evaporation system provided by the invention.

Detailed Description

Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative and is in no way intended to limit the disclosure, its application, or uses. The present disclosure may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. It should be noted that: the relative arrangement of parts and steps, the composition of materials, numerical expressions and numerical values set forth in these embodiments are to be construed as merely illustrative, and not as limitative, unless specifically stated otherwise.

As used in this disclosure, "first", "second": and the like, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The word "comprising" or "comprises", and the like, means that the element preceding the word covers the element listed after the word, and does not exclude the possibility that other elements are also covered. "upper", "lower", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships may also be changed accordingly.

In the present disclosure, when a specific component is described as being located between a first component and a second component, there may or may not be intervening components between the specific component and the first component or the second component. When it is described that a specific component is connected to other components, the specific component may be directly connected to the other components without having an intervening component, or may be directly connected to the other components without having an intervening component.

All terms (including technical or scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs unless specifically defined otherwise. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail, but are intended to be part of the specification where appropriate.

At present, the condition that a fuel pipeline in an evaporation system leaks is monitored and diagnosed without considering the influence of relevant factors on the vacuum degree, so that the condition of inaccurate diagnosis can be caused. For example, the reduction of the vacuum degree may be a large change in the vacuum degree due to the generation of oil vapor, or may be an abnormal fluctuation in the attenuation of the vacuum degree due to the external force applied to the oil tank, thereby affecting the determination.

Therefore, at present, for the air tightness detection of an evaporation system, only the vacuum degree is simply established, the attenuation condition of the vacuum degree is monitored, the judgment is made only by roughly utilizing the pressure difference between the starting point and the end point of the vacuum degree, the influence of factors such as oil vapor, external environment and the like on the vacuum degree in practice and the attenuation process are not fully considered, the monitoring result is inaccurate, and the problem of false alarm fault occurs.

The fuel evaporation system includes: three ports of carbon tank electromagnetic valve, carbon tank ventilation valve and fuel tank cover, and the whole space enveloped by the three ports. Wherein the carbon tank solenoid valve sets up on the pipeline between carbon tank desorption mouth and the air intake manifold for the flow of control carbon tank desorption mouth and air intake manifold between pipeline.

As shown in fig. 1 and fig. 2, in an actual implementation process, the method for diagnosing leakage of an evaporation system provided in this embodiment specifically includes the following steps:

and step S1, carrying out fault detection on the related components.

Specifically, after the vehicle starts to operate, short circuit detection and/or disconnection detection are/is performed on relevant components. The related components refer to components related to the evaporation system, and exemplarily comprise a carbon tank solenoid valve, a carbon tank vent valve, a fuel tank pressure sensor and a fuel level sensor.

Step S2, it is determined whether the relevant diagnosis condition is satisfied.

In an embodiment of the evaporation system leakage diagnosis method of the present invention, the step S2 may specifically include:

and step S21, vehicle parameters are acquired.

Wherein the vehicle parameters comprise vehicle state parameters and/or vehicle environment parameters. Specifically, the vehicle state parameters include: coolant temperature, oil level, rotational speed, and vehicle speed. The vehicle environmental parameters include ambient temperature and altitude.

And step S22, judging whether the acquired vehicle parameters meet preset parameter requirements.

And step S3, when the relevant parts are normal and the relevant diagnosis conditions are met, closing the carbon tank electromagnetic valve and the carbon tank vent valve.

And step S4, monitoring whether the oil vapor generation rate in the oil tank is smaller than a preset value, and if not, not diagnosing.

And step S5, if yes, judging whether the evaporation system leaks or not through a vacuum degree attenuation test.

In the invention, whether the evaporation system leaks or not is judged through a total attenuation test, a sectional attenuation test and a slope convex test. In an embodiment of the evaporation system leakage diagnosis method of the present invention, the step S5 may specifically include:

and step S51, establishing vacuum degree and carrying out vacuum degree attenuation test.

Specifically, the carbon tank vent valve is closed, the carbon tank electromagnetic valve is opened, the carbon tank electromagnetic valve is closed after the vacuum degree of the oil tank is pumped to a preset value, and the attenuation test is carried out.

And step S52, judging whether the attenuation slope is larger than a preset value.

Specifically, within a preset time, whether the total attenuation slope of the vacuum degree is greater than a preset attenuation slope value is judged.

And step S53, if yes, performing attenuation subsection test and subsection slope convex test, and judging whether the attenuation subsection test and the subsection slope convex test are larger than respective set values.

When the attenuation slope is greater than the preset value, performing an attenuation section test and a section slope convex test, and determining whether the attenuation section test and the section slope convex test are greater than respective set values, specifically including:

and step S531, performing a segmental attenuation test, and dividing the total attenuation preset time into a plurality of small time segments.

Step S532, when the subsection attenuation test is carried out, whether the vacuum degree attenuation slope of any subsection is larger than the subsection attenuation slope preset value or not is judged.

Step S533, a convex segment slope test is performed, and it is determined whether the difference between the vacuum degree attenuation slope of the current segment and the vacuum degree attenuation slope of the previous segment is greater than a convex segment slope preset value.

By step S533, it can be ensured that the attenuation is performed normally linearly.

And step S54, if yes, judging that the evaporation system has leakage, and if not, judging that the evaporation system has no leakage.

And step S55, if the attenuation slope is not greater than the preset value, judging that the evaporation system has no leakage.

When the related components are all normal and the related diagnosis conditions are all met, the system controls the carbon tank electromagnetic valve and the carbon tank vent valve to be closed, whether the oil vapor generation rate in the oil tank is smaller than a preset value or not is monitored, if so, the system controls the carbon tank vent valve to be closed and controls the carbon tank electromagnetic valve to be opened, the carbon tank electromagnetic valve is closed after the vacuum degree of the oil tank is pumped to the preset value, and the attenuation test is carried out. Firstly, judging the total attenuation slope of the vacuum degree within a preset time, and when the total attenuation slope is greater than a preset value, carrying out a subsection attenuation test, namely dividing the total attenuation preset time into a plurality of small sections of time, wherein the attenuation slope of the vacuum degree of any subsection is greater than the preset value; and then, carrying out a convex test of the sectional slope, namely, ensuring that the difference value between the vacuum degree attenuation slope of the current section and the vacuum degree attenuation slope of the previous section does not exceed a preset value, and ensuring that the attenuation is carried out normally and linearly. Therefore, when the total attenuation test, the subsection attenuation test and the slope convex test all meet the failure condition, the leakage of the evaporation system is judged.

Further, in some embodiments of the present invention, the method for diagnosing leakage of an evaporation system further comprises:

when the evaporation system is judged to have no leakage, the fault is not reported;

and when the leakage fault of the evaporation system is judged, the diagnosis result is output through the vehicle-mounted computer and the fault is reported.

According to the leakage diagnosis method for the evaporation system, provided by the embodiment of the invention, the influence caused by oil vapor is avoided and the misjudgment is avoided by monitoring the oil vapor in the oil tank; by accurately judging the vacuum degree attenuation condition of the oil tank, the air tightness of the evaporation system can be effectively monitored, the influence of external factors on the vacuum degree is avoided, and misjudgment is avoided; when the integral attenuation degree is smaller than a set value, judging that no leakage exists, and when the integral attenuation degree is larger than the set value, carrying out a subsection attenuation test and a subsection slope convex test to ensure that the attenuation process is normal, and accurately judging the attenuation degree, thereby accurately judging the air tightness of the evaporation system and eliminating the influence of the outside on the attenuation process.

Thus, various embodiments of the present disclosure have been described in detail. Some details that are well known in the art have not been described in order to avoid obscuring the concepts of the present disclosure. It will be fully apparent to those skilled in the art from the foregoing description how to practice the presently disclosed embodiments.

Although some specific embodiments of the present disclosure have been described in detail by way of example, it should be understood by those skilled in the art that the foregoing examples are for purposes of illustration only and are not intended to limit the scope of the present disclosure. It will be understood by those skilled in the art that various changes may be made in the above embodiments or equivalents may be substituted for elements thereof without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.