Gas Nozzle Leakage Diagnosis Method and Vehicle

Abstract

The present invention belongs to the technical field of vehicles, and discloses a method for diagnosing gas nozzle leakage and a vehicle. The method for diagnosing gas nozzle leakage includes that when the ECU receives a power-off instruction, it queries the status information of the gas nozzle. If the status information of the gas nozzle shows that there is a leakage fault in the gas nozzle, it controls the ECU to power off. If the status information of the gas nozzle shows that there is no leakage fault in the gas nozzle, a gas nozzle leakage diagnosis is carried out before the ECU powers off. The gas nozzle leakage diagnosis before the ECU powers off includes: closing the gas cut-off valve and monitoring the gas pressure between the gas cut-off valve and the gas injection valve; calculating the gas pressure change rate within each preset interval duration within the first preset time, and making a judgment on the gas nozzle leakage diagnosis result. The judgment on the gas nozzle leakage diagnosis result includes: if the minimum value among the gas pressure change rates in the current gas nozzle leakage diagnosis is less than the preset gas pressure change rate, it is judged that there is a leakage fault in the gas nozzle.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicles, and particularly to a method for diagnosing gas nozzle leakage and a vehicle. Background Art

[0002] The gas nozzle is an important component of a gas engine. Leakage of the gas nozzle can cause an abnormal air-fuel ratio of the gas engine, deteriorate the exhaust gas emissions, and even endanger the running safety of the vehicle. As Figure 1 shown in the structural schematic diagram of the gas nozzle, in the existing method for diagnosing gas nozzle leakage, when the ECU (electronic control unit, also known as the in-vehicle computer) receives a power-off command, the gas injection valve 1 and the gas cut-off valve 2 are closed. At this time, the pipeline between the gas cut-off valve 2 and the gas injection valve 1 is equivalent to a sealed container, and the gas pressure drop within a certain period of time is calculated. If the gas pressure drop is lower than the limit value, it is considered that there is a leakage. Since when the gas injection valve 1 and the gas cut-off valve 2 are closed, the gas suddenly changes from a flowing state to a static state, which will cause the gas pressure between the gas cut-off valve 2 and the gas injection valve 1 to rise to a certain extent after the gas cut-off valve 2 is closed. This phenomenon of the gas pressure rising between the gas cut-off valve 2 and the gas injection valve 1 after the gas cut-off valve 2 is closed will result in that when there is a leakage in the gas nozzle but the leakage is relatively slight, the calculated gas pressure drop within a certain period of time by the existing gas nozzle leakage diagnosis method is smaller than the actual value, and even the drop amount is zero, thus leading to the failure to diagnose the slight leakage of the gas nozzle.

[0003] Therefore, there is an urgent need for a method for diagnosing gas nozzle leakage and a vehicle to solve the above problems. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for diagnosing gas nozzle leakage and a vehicle, which can effectively diagnose the slight leakage of the gas nozzle.

[0005] To achieve this purpose, the present invention adopts the following technical solutions:

[0006] A method for diagnosing gas nozzle leakage includes:

[0007] When the ECU receives a power-off command, query the gas nozzle status information. If the gas nozzle status information shows that there is a leakage fault in the gas nozzle, control the ECU to power off. If the gas nozzle status information shows that there is no leakage fault in the gas nozzle, perform the gas nozzle leakage diagnosis before the ECU powers off;

[0008] The gas nozzle leakage diagnosis before the ECU powers off includes:

[0009] Close the gas cut-off valve and monitor the gas pressure between the gas cut-off valve and the gas injection valve;

[0010] Calculate the gas pressure change rate between the gas cut-off valve and the gas injection valve within each preset interval duration during the first preset time, and judge the gas nozzle leakage diagnosis result;

[0011] The judgment of the gas nozzle leakage diagnosis result includes:

[0012] If the minimum value among the gas pressure change rates in the current gas nozzle leakage diagnosis is less than the preset gas pressure change rate, it is judged that the gas nozzle has a leakage fault, and the gas nozzle fault information is stored in the gas nozzle status information. The gas nozzle fault information includes that the gas nozzle is in a leakage state. If the minimum value among the gas pressure change rates in the current gas nozzle leakage diagnosis is not less than the preset gas pressure change rate, it is judged that the gas nozzle has no leakage fault.

[0013] Preferably, when the ECU does not receive a power-off command and the engine speed is less than the set speed, query the gas nozzle status information. If the gas nozzle status information shows that the gas nozzle has a leakage fault, control the ECU to power off. If the gas nozzle status information shows that the gas nozzle has no leakage fault, perform the gas nozzle leakage diagnosis before the ECU powers off.

[0014] Preferably, in the gas nozzle leakage diagnosis before the ECU powers off, after closing the gas cut-off valve, it further includes:

[0015] Wait for the second preset time, and then calculate the gas pressure change rate between the gas cut-off valve and the gas injection valve within each preset interval duration during the first preset time, and judge the gas nozzle leakage diagnosis result.

[0016] Preferably, after the ECU powers on, query the gas nozzle status information. If the gas nozzle status information shows that the gas nozzle has no leakage fault, perform the gas nozzle leakage diagnosis after the ECU powers on;

[0017] The gas nozzle leakage diagnosis after the ECU powers on includes:

[0018] Open the gas cut-off valve. After the third preset time, close the gas cut-off valve and monitor the gas pressure between the gas cut-off valve and the gas injection valve;

[0019] Calculate the gas pressure change rate between the gas cut-off valve and the gas injection valve within each preset interval duration during the fourth preset time, and judge the gas nozzle leakage diagnosis result.

[0020] Preferably, the gas nozzle fault information further includes the minimum value among the gas pressure change rates in the gas nozzle leakage diagnosis after the ECU powers on this time;

[0021] After the ECU is powered on, after querying the status information of the gas nozzle, it further includes that if the status information of the gas nozzle shows that there is a leakage fault in the gas nozzle, the gas nozzle leakage fault action table is queried according to the minimum value among the gas pressure change rates corresponding to the leakage fault, and the corresponding fault action is executed.

[0022] Preferably, if it is determined that there is a leakage fault in the gas nozzle during the gas nozzle leakage diagnosis after the current ECU is powered on, the gas nozzle leakage fault action table is queried according to the minimum value among the gas pressure change rates in the gas nozzle leakage diagnosis after the current ECU is powered on, and the corresponding fault action is executed.

[0023] Preferably, it further includes:

[0024] After the ECU is powered on, when receiving an engine start instruction, it is determined whether the time interval between the moment when the ECU is powered on and the moment when the engine start instruction is received is less than the sum of a third preset time and a fourth preset time;

[0025] If the time interval between the moment when the ECU is powered on and the moment when the engine start instruction is received is less than the sum of the third preset time and the fourth preset time, the gas nozzle leakage diagnosis after the current ECU is powered on is stopped.

[0026] Preferably, the gas nozzle leakage diagnosis before the ECU is powered off further includes that if the gas pressure between the gas cut-off valve and the gas injection valve is less than the set pressure when the gas cut-off valve is closed, the gas nozzle leakage diagnosis before the current ECU is powered off is stopped;

[0027] The gas nozzle leakage diagnosis after the ECU is powered on further includes that if the gas pressure between the gas cut-off valve and the gas injection valve is less than the set pressure when the gas cut-off valve is closed, the gas nozzle leakage diagnosis after the current ECU is powered on is stopped.

[0028] Preferably, the gas pressure change rate is equal to the ratio of the difference between the gas pressure value between the gas cut-off valve and the gas injection valve at the end of a preset interval duration and the gas pressure value between the gas cut-off valve and the gas injection valve at the start of the preset interval duration to the preset interval duration.

[0029] A vehicle performs gas nozzle leakage diagnosis using the gas nozzle leakage diagnosis method described in any one of the above.

[0030] Advantages of the present invention:

[0031] The gas nozzle leakage diagnosis method and vehicle of the present invention calculate the gas pressure change rate within each preset interval duration within the first preset time after closing the gas cut-off valve. As long as there is a leakage in the gas nozzle, even if the gas pressure between the gas cut-off valve and the gas injection valve rises after the gas cut-off valve is closed, the gas pressure change rate within each preset interval duration after the gas pressure rises can still accurately reflect whether there is a leakage in the gas nozzle. Therefore, by comparing the minimum value among the gas pressure change rates with the preset gas pressure change rate to determine whether there is a leakage fault in the gas nozzle, it can ensure that even a slight leakage of the gas nozzle can be effectively diagnosed. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a schematic structural diagram of a gas nozzle provided in the background art of the present invention;

[0033] Figure 2 is a flowchart of the gas nozzle leakage diagnosis method provided in an embodiment of the present invention;

[0034] Figure 3 is a flowchart of the gas nozzle leakage diagnosis before the ECU powers off provided in an embodiment of the present invention;

[0035] Figure 4 is a flowchart of the gas nozzle leakage diagnosis result judgment provided in an embodiment of the present invention;

[0036] Figure 5 is a flowchart of the gas nozzle leakage diagnosis before the ECU powers on provided in an embodiment of the present invention.

[0037] In the figure:

[0038] 1. Gas injection valve; 2. Gas cut-off valve; 3. Pressure sensor. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0039] The present invention will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only for explaining the present invention, rather than limiting the present invention. Additionally, it should be noted that for the sake of description, only parts related to the present invention are shown in the drawings, not all structures.

[0040] In the description of the present invention, unless otherwise clearly defined and limited, the terms "connected", "connected to", and "fixed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0041] In the present invention, unless otherwise clearly specified and defined, the first feature being "above" or "below" the second feature may include direct contact between the first and second features, or may include the first and second features not being in direct contact but being in contact through additional features therebetween. Moreover, the first feature being "above", "over" and "on top of" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "beneath" and "underneath" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the horizontal height of the first feature is less than that of the second feature.

[0042] In the description of this embodiment, the orientation or positional relationships such as "above", "below", "right", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of description and simplifying the operation, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0043] As Figures 2 - 4 shown, this embodiment provides a method for diagnosing gas nozzle leakage, including: when the ECU receives a power-off instruction, query the gas nozzle status information. If the gas nozzle status information shows that there is a leakage fault in the gas nozzle, control the ECU to power off. If the gas nozzle status information shows that there is no leakage fault in the gas nozzle, perform a gas nozzle leakage diagnosis before the ECU powers off; the gas nozzle leakage diagnosis before the ECU powers off includes: closing the gas cut-off valve 2, monitoring the gas pressure between the gas cut-off valve 2 and the gas injection valve 1. In this embodiment, the gas pressure between the gas cut-off valve 2 and the gas injection valve 1 is monitored by the pressure sensor 3; calculate the gas pressure change rate between the gas cut-off valve 2 and the gas injection valve 1 within each preset interval duration within the first preset time, and make a judgment on the gas nozzle leakage diagnosis result; the judgment on the gas nozzle leakage diagnosis result includes: if the minimum value among the gas pressure change rates in this gas nozzle leakage diagnosis is less than the preset gas pressure change rate, it is determined that there is a leakage fault in the gas nozzle, and store the gas nozzle fault information in the gas nozzle status information. The gas nozzle fault information includes that the gas nozzle is in a leakage state. If the minimum value among the gas pressure change rates in this gas nozzle leakage diagnosis is not less than the preset gas pressure change rate, it is determined that there is no leakage fault in the gas nozzle. When the judgment on the gas nozzle leakage diagnosis result is completed, the gas nozzle leakage diagnosis before the ECU powers off ends.

[0044] The gas nozzle leakage diagnosis method of this embodiment calculates the gas pressure change rate within each preset interval duration within the first preset time after the gas cut-off valve 2 is closed. As long as there is a leakage in the gas nozzle, even if the gas pressure between the gas cut-off valve 2 and the gas injection valve 1 rises after the gas cut-off valve 2 is closed, the gas pressure change rate within each preset interval duration after the gas pressure rises can still accurately reflect whether there is a leakage in the gas nozzle. Therefore, by comparing the minimum value among the gas pressure change rates with the preset gas pressure change rate, it can be determined whether there is a leakage fault in the gas nozzle, and it can ensure that even slight leakage of the gas nozzle can be effectively diagnosed.

[0045] The specific values of the first preset time and the preset interval duration are selected according to needs. In this embodiment, the first preset time is 2 seconds and the preset interval duration is 0.5 seconds. That is to say, the first preset time contains four preset interval durations. Calculating the gas pressure change rate within each preset interval duration within the first preset time means calculating the gas pressure change rates within four time periods: within 0.5 seconds after the gas cut-off valve 2 is closed, from 0.5 seconds to 1 second, from 1 second to 1.5 seconds, and from 1.5 seconds to 2 seconds. Comparing the minimum value among the four calculated gas pressure change rates with the preset gas pressure change rate to determine whether there is a leakage fault in the gas nozzle.

[0046] Optionally, when the ECU does not receive a power-off command and the engine speed is less than the set speed, query the gas nozzle status information. If the gas nozzle status information indicates that there is a leakage fault in the gas nozzle, control the ECU to power off. If the gas nozzle status information indicates that there is no leakage fault in the gas nozzle, perform a gas nozzle leakage diagnosis before the ECU powers off. In this embodiment, the set speed is the speed when the vehicle is close to stalling, and the specific value is selected according to needs. When the ECU does not receive a power-off command but the engine speed is less than the set speed, it means that the driver has performed a parking operation of directly cutting off the gas before the ECU powers off. That is to say, when the ECU does not receive a power-off command and the engine speed is less than the set speed and when the ECU receives a power-off command are two situations indicating that this driving cycle is about to end. Regardless of which of the two situations occurs, a gas nozzle leakage diagnosis is performed before the ECU powers off once, so that the gas nozzle leakage diagnosis method of this embodiment can timely diagnose newly occurring gas nozzle leakage faults during the vehicle operation at the end of this driving cycle, ensuring the normal air-fuel ratio of the gas engine and the safety of vehicle operation.

[0047] It should be noted that when the ECU does not receive a power-off command and the engine speed is less than the set speed, and when the ECU receives a power-off command, the gas injection control logic of the engine will control the gas injection valve 1 to close, and before the ECU powers on, the gas injection valve 1 is also in the closed state. Therefore, the gas nozzle leakage diagnosis method in this embodiment does not control the gas injection valve 1.

[0048] Optionally, in the gas nozzle leakage diagnosis before the ECU is powered off, after closing the gas shut-off valve, it also includes: waiting for a second preset time, and then calculating the gas pressure change rate between the gas shut-off valve 2 and the gas injection valve 1 in each preset interval time within the first preset time, and judging the gas nozzle leakage diagnosis result. Within a period of time after the gas injection valve 1 and the gas shut-off valve 2 are closed, the gas pressure between the gas shut-off valve 2 and the gas injection valve 1 will rise slightly as a whole, but the rising process is not stable, especially in the early stage after the gas injection valve 1 and the gas shut-off valve 2 are closed, the fluctuation is more violent, so after closing the gas shut-off valve, first wait for the second preset time, and after the end time with the largest gas pressure fluctuation between the gas shut-off valve 2 and the gas injection valve 1 has passed, calculate the gas pressure change rate between the gas shut-off valve 2 and the gas injection valve 1 in each preset interval time within the first preset time, and judge the gas nozzle leakage diagnosis result, which is conducive to improving the stability of the gas pressure change rate between the gas shut-off valve 2 and the gas injection valve 1 and avoiding false alarms. The specific value of the second preset time is selected according to needs.

[0049] Optionally, after the ECU is powered on, the gas nozzle status information is queried. If the gas nozzle status information shows that there is no leakage fault in the gas nozzle, the gas nozzle leakage diagnosis after the ECU is powered on is performed; the gas nozzle leakage diagnosis after the ECU is powered on includes: opening the gas shut-off valve 2 for a third preset time, closing the gas shut-off valve 2, monitoring the gas pressure between the gas shut-off valve 2 and the gas injection valve 1; calculating the gas pressure change rate between the gas shut-off valve 2 and the gas injection valve 1 within each preset interval time within the fourth preset time, and judging the gas nozzle leakage diagnosis result. When the gas nozzle leakage diagnosis result is judged, the gas nozzle leakage diagnosis after the ECU is powered on is completed. The gas nozzle status information after the ECU is powered on shows that the gas nozzle has no leakage fault, indicating that the gas nozzle leakage diagnosis before the ECU is powered off at the end of the previous driving cycle determines that the gas nozzle has no leakage fault, or the gas nozzle leakage diagnosis before the ECU is powered off at the end of the previous driving cycle determines that the gas nozzle has a leakage fault but the fault has been repaired. At this time, a gas nozzle leakage diagnosis after the ECU is powered on is performed so that the driver can know the exact state of the gas nozzle at the beginning of this driving cycle, avoiding the gas nozzle from the end of the previous driving cycle to the beginning of this driving cycle Leakage fault occurs and the driver does not know. The specific value of the fourth preset time is selected as needed. In this embodiment, the fourth preset time is the same as the first preset time in the gas nozzle leakage diagnosis before the ECU is powered off, and is selected as 2 seconds.

[0050] It should be noted that before the ECU power-down diagnosis starts, the engine is running, that is, the gas is flowing. When the gas injection valve and the gas cut-off valve are suddenly closed, the gas pressure between the gas cut-off valve 2 and the gas injection valve 1 fluctuates violently. Therefore, a separate delay time is required. During the power-up process, the engine is not running and there is an inflation process. The calibrated inflation time is generally slightly longer than the actual required time, which is equivalent to an additional delay. That is, when the gas cut-off valve is closed, the gas flow has stabilized and does not flow. Therefore, there will be no sudden increase in the gas pressure between the gas cut-off valve 2 and the gas injection valve 1 after the gas cut-off valve is closed. So, it is not necessary to wait for the second preset time before diagnosing the gas nozzle leakage as in the case of ECU power-down.

[0051] Optionally, the gas nozzle fault information further includes the minimum value among the gas pressure change rates in the gas nozzle leakage diagnosis after the ECU is powered on this time; after the ECU is powered on and the gas nozzle status information is queried, if the gas nozzle status information indicates that there is a leakage fault in the gas nozzle, then according to the minimum value among the gas pressure change rates corresponding to the leakage fault, the gas nozzle leakage fault action table is queried to execute the corresponding fault action. Different fault actions are executed according to the magnitude of the minimum value among the gas pressure change rates to distinguish between ordinary leakage and serious leakage. The gas nozzle leakage fault action table is pre-stored in the ECU.

[0052] Optionally, if it is determined that there is a leakage fault in the gas nozzle in the gas nozzle leakage diagnosis after the ECU is powered on this time, then according to the minimum value among the gas pressure change rates in the gas nozzle leakage diagnosis after the ECU is powered on this time, the gas nozzle leakage fault action table is queried to execute the corresponding fault action. Different fault actions are executed according to the magnitude of the minimum value among the gas pressure change rates to distinguish between ordinary leakage and serious leakage.

[0053] Optionally, such as Figure 5As shown, the gas nozzle leakage diagnosis method of this embodiment further includes: after the ECU is powered on, when receiving an engine start command, it is judged whether the time interval between the moment when the ECU is powered on and the moment when the engine start command is received is less than the sum of a third preset time and a fourth preset time; if the time interval between the moment when the ECU is powered on and the moment when the engine start command is received is less than the sum of the third preset time and the fourth preset time, the gas nozzle leakage diagnosis after this ECU power-on is stopped. The specific value of the third preset time is selected according to needs. In this embodiment, the third preset time is 1 second. When the driver starts the vehicle, it is divided into two stages. The first stage is when the ECU is powered on but the engine has not started running yet, and the second stage is when the engine start command is received, and at this time the vehicle enters the driving preparation stage. Due to the differences in vehicles and the driving habits of drivers, the time interval between the first stage and the second stage will vary. At the moment when the engine start command is received, if the time interval between the moment when the ECU is powered on and the moment when the engine start command is received is less than the sum of the third preset time and the first preset time, it means that the gas nozzle leakage diagnosis after this ECU power-on has not been completed yet. However, since the vehicle enters the driving preparation stage at this time, in order to avoid affecting the normal driving of the vehicle, the gas nozzle leakage diagnosis after this ECU power-on is stopped at this time.

[0054] Optionally, the gas nozzle leakage diagnosis before the ECU is powered off further includes that if the gas pressure between the gas cut-off valve 2 and the gas injection valve 1 is less than the set pressure when the gas cut-off valve 2 is closed, the gas nozzle leakage diagnosis before this ECU power-off is stopped; the gas nozzle leakage diagnosis after the ECU is powered on further includes that if the gas pressure between the gas cut-off valve 2 and the gas injection valve 1 is less than the set pressure when the gas cut-off valve 2 is closed, the gas nozzle leakage diagnosis after this ECU power-on is stopped. If the gas pressure between the gas cut-off valve 2 and the gas injection valve 1 is less than the set pressure when the gas cut-off valve 2 is closed, then the gas pressure between the gas cut-off valve 2 and the gas injection valve 1 is too low at this time, the pressure is unstable, and false alarms are likely to occur.

[0055] Optionally, the gas pressure change rate is equal to the ratio of the difference between the gas pressure value between the gas cut-off valve 2 and the gas injection valve 1 at the end of the preset interval duration and the gas pressure value between the gas cut-off valve 2 and the gas injection valve 1 at the start of the preset interval duration to the preset interval duration. If there is a leakage fault in the gas nozzle, then within each preset interval duration after the gas pressure between the gas cut-off valve 2 and the gas injection valve 1 rises after the gas cut-off valve 2 is closed, the gas pressure change rate should be negative. The more serious the gas nozzle leakage is, the smaller the gas pressure change rate is, and the larger the absolute value of the gas pressure change rate is.

[0056] For the gas nozzle leakage diagnosis method provided in this embodiment, when the post - power gas nozzle leakage diagnosis on the ECU of this driving cycle determines that there is no leakage fault in the gas nozzle or the post - power gas nozzle leakage diagnosis on the ECU fails to complete, another gas nozzle leakage diagnosis is performed when the ECU of this driving cycle receives a power - off command. Thus, newly - occurring gas nozzle leakage faults can be diagnosed in a timely manner, and it is ensured that at least one gas nozzle leakage diagnosis is completed in each driving cycle.

[0057] Optionally, after the gas nozzle fault is repaired, the gas nozzle fault information can be manually cleared.

[0058] This embodiment also provides a vehicle that uses the above - mentioned gas nozzle leakage diagnosis method to perform gas nozzle leakage diagnosis.

[0059] Obviously, the above - mentioned embodiments of the present invention are merely examples for clearly explaining the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, various obvious changes, re - adjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the implementation manners here. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. A method for diagnosing leakage of a gas nozzle, characterized in that, Including: After the ECU is powered on, query the status information of the gas nozzle. After querying the status information of the gas nozzle, it includes: If the status information of the gas nozzle shows that there is a leakage fault in the gas nozzle, query the gas nozzle leakage fault action table according to the minimum value among the gas pressure change rates corresponding to the leakage fault and execute the corresponding fault action; If the status information of the gas nozzle shows that there is no leakage fault in the gas nozzle, perform the gas nozzle leakage diagnosis after the ECU is powered on; The gas nozzle leakage diagnosis after the ECU is powered on includes: Open the gas cut-off valve (2), and after a third preset time, close the gas cut-off valve (2), and monitor the gas pressure between the gas cut-off valve (2) and the gas injection valve (1); Calculate the gas pressure change rate between the gas cut-off valve (2) and the gas injection valve (1) within each preset interval duration within a fourth preset time, and perform the judgment of the gas nozzle leakage diagnosis result; If the gas nozzle leakage diagnosis after the current ECU power-on determines that there is a leakage fault in the gas nozzle, query the gas nozzle leakage fault action table according to the minimum value among the gas pressure change rates in the gas nozzle leakage diagnosis after the current ECU power-on and execute the corresponding fault action; When the ECU receives the engine start command after being powered on, judge whether the time interval between the ECU power-on moment and the moment when the engine start command is received is less than the sum of the third preset time and the fourth preset time. If the time interval between the ECU power-on moment and the moment when the engine start command is received is less than the sum of the third preset time and the fourth preset time, stop the gas nozzle leakage diagnosis after the current ECU power-on; When the ECU receives the power-off command, query the status information of the gas nozzle. If the status information of the gas nozzle shows that there is a leakage fault in the gas nozzle, control the ECU to power off. If the status information of the gas nozzle shows that there is no leakage fault in the gas nozzle, perform the gas nozzle leakage diagnosis before the ECU powers off; The gas nozzle leakage diagnosis before the ECU powers off includes: Close the gas cut-off valve (2), and monitor the gas pressure between the gas cut-off valve (2) and the gas injection valve (1); Calculate the gas pressure change rate between the gas cut-off valve (2) and the gas injection valve (1) within each preset interval duration within a first preset time, and perform the judgment of the gas nozzle leakage diagnosis result; The judgment of the gas nozzle leakage diagnosis result includes: If the minimum value among the gas pressure change rates in the current gas nozzle leakage diagnosis is less than the preset gas pressure change rate, it is determined that there is a leakage fault in the gas nozzle, and store the gas nozzle fault information in the gas nozzle status information. The gas nozzle fault information includes that the gas nozzle is in a leakage state. If the minimum value among the gas pressure change rates in the current gas nozzle leakage diagnosis is not less than the preset gas pressure change rate, it is determined that there is no leakage fault in the gas nozzle.

2. The gas nozzle leakage diagnosis method according to claim 1, wherein When the ECU does not receive the power-off command and the engine speed is less than the set speed, query the status information of the gas nozzle. If the status information of the gas nozzle shows that there is a leakage fault in the gas nozzle, control the ECU to power off. If the status information of the gas nozzle shows that there is no leakage fault in the gas nozzle, perform the gas nozzle leakage diagnosis before the ECU powers off.

3. The gas nozzle leakage diagnosis method according to claim 1 or 2, characterized in that, Before the ECU is powered off, in the gas nozzle leakage diagnosis, after closing the gas cut-off valve, it further includes: Wait for a second preset time, and then calculate the gas pressure change rate between the gas cut-off valve (2) and the gas injection valve (1) within each preset interval duration during the first preset time, and judge the gas nozzle leakage diagnosis result.

4. The gas nozzle leakage diagnosis method according to claim 1, wherein, Before the ECU is powered off, the gas nozzle leakage diagnosis further includes that if the gas pressure between the gas cut-off valve (2) and the gas injection valve (1) is less than the set pressure when the gas cut-off valve (2) is closed, stop the gas nozzle leakage diagnosis before the ECU is powered off this time; After the ECU is powered on, the gas nozzle leakage diagnosis further includes that if the gas pressure between the gas cut-off valve (2) and the gas injection valve (1) is less than the set pressure when the gas cut-off valve (2) is closed, stop the gas nozzle leakage diagnosis after the ECU is powered on this time.

5. The gas nozzle leakage diagnosis method according to claim 1, characterized in that, The gas pressure change rate is equal to the ratio of the difference between the gas pressure value between the gas cut-off valve (2) and the gas injection valve (1) at the end of the preset interval duration and the gas pressure value between the gas cut-off valve (2) and the gas injection valve (1) at the start of the preset interval duration to the preset interval duration.

6. A vehicle, characterized in that, Use the gas nozzle leakage diagnosis method according to any one of claims 1-5 to conduct gas nozzle leakage diagnosis.

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