Method, device and system for determining a crankcase ventilation malfunction

Abstract

This application provides a method, apparatus, and system for determining crankcase ventilation faults. The method includes: determining an intake air flow rate based on actual temperature, a first actual pressure, and a second actual pressure, where the first actual pressure is the inlet pressure of the oil-gas separator under actual operating conditions, and the second actual pressure is the outlet pressure of the oil-gas separator under actual operating conditions; determining a first demand pressure based on the intake air flow rate and a first mapping relationship, where the first demand pressure is the inlet pressure of the oil-gas separator under normal operating conditions, defined as when the ventilation duct is neither detached nor leaking; and determining that a crankcase ventilation fault exists if the ratio of the first actual pressure to the first demand pressure is greater than a first preset value. This method solves the problem that existing detection methods based on the difference between atmospheric pressure and the pressure inside the crankcase piping cannot accurately detect crankcase ventilation faults.

Description

Technical Field

[0001] This application relates to the field of automotive technology, and more specifically, to a method, apparatus, computer-readable storage medium, and system for determining crankcase ventilation faults. Background Technology

[0002] For natural gas engines, closed crankcase ventilation systems are generally used to reduce crankcase exhaust gas emissions into the atmosphere. Existing crankcase ventilation strategies determine the presence of a ventilation fault by checking if the difference between atmospheric pressure and the pressure inside the crankcase piping is below a calibrated threshold. This method works well when the crankcase piping is completely disconnected. However, if the crankcase ventilation piping is leaking or not completely disconnected, the pressure inside the crankcase piping will still be much lower than atmospheric pressure, significantly reducing the accuracy of crankcase ventilation fault detection. Summary of the Invention

[0003] The main objective of this application is to provide a method, apparatus, computer-readable storage medium, and system for determining crankcase ventilation faults, in order to solve the problem that existing detection methods based on the difference between atmospheric pressure and crankcase pipeline pressure cannot accurately detect crankcase ventilation faults.

[0004] According to one aspect of the embodiments of this application, a method for determining a crankcase ventilation failure is provided. The crankcase is connected to a ventilation duct, and an oil-gas separator is provided on the ventilation duct. The method includes: acquiring an actual temperature, a first actual pressure, and a second actual pressure; determining an intake flow rate based on the actual temperature, the first actual pressure, and the second actual pressure, wherein the first actual pressure is the air pressure at the inlet of the oil-gas separator under actual operating conditions, the second actual pressure is the air pressure at the outlet of the oil-gas separator under actual operating conditions, the intake flow rate is the air volume entering the ventilation duct per unit time under actual operating conditions, and the actual temperature is the temperature inside the ventilation duct under actual operating conditions; determining a first demand pressure based on the intake flow rate and a first mapping relationship, wherein the first mapping relationship is a mapping relationship between the intake flow rate and the first demand pressure, and the first demand pressure is the air pressure at the inlet of the oil-gas separator under normal operating conditions, wherein normal operating conditions are conditions where the ventilation duct is neither detached nor leaking; and determining that the crankcase has a ventilation failure when the ratio of the first actual pressure to the first demand pressure is greater than a first preset value.

[0005] Optionally, determining the intake flow rate based on the actual temperature, the first actual pressure, and the second actual pressure includes: according to the formula The intake air flow rate is calculated, where Mf is the intake air flow rate, Ae is the diameter of the ventilation duct, Pus is the first actual pressure, R is the ideal gas constant, and T is the actual temperature. Let P be the stream function. i It is the ratio of the first actual pressure to the second actual pressure.

[0006] Optionally, before determining the first demand pressure based on the intake flow rate and the first mapping relationship, the method further includes: acquiring multiple intake flow rates and corresponding first demand pressures under normal operating conditions, wherein the intake flow rate and the first demand pressure correspond one-to-one; and determining the first mapping relationship based on all the intake flow rates and corresponding first demand pressures.

[0007] Optionally, according to the formula After calculating the intake flow rate, the method further includes: determining a second demand pressure based on the intake flow rate and the second mapping relationship, wherein the second demand pressure is the gas pressure at the outlet of the oil-gas separator under normal operating conditions, and the second mapping relationship is the mapping relationship between the intake flow rate and the second demand pressure; and determining that the crankcase has a ventilation fault if the ratio of the second actual pressure to the second demand pressure is greater than a second preset value.

[0008] Optionally, before determining the second demand pressure based on the intake flow rate and the second mapping relationship, the method further includes: acquiring multiple intake flow rates and corresponding second demand pressures under normal operating conditions, wherein the intake flow rate and the second demand pressure correspond one-to-one; and determining the second mapping relationship based on all the intake flow rates and corresponding second demand pressures.

[0009] Optionally, based on the condition that the ratio of the first actual pressure to the first demand pressure is greater than the first preset value, after determining that there is a ventilation failure in the crankcase, the method further includes: if the first failure time is greater than the first preset time, sending a crankcase ventilation failure message notification to the user terminal, wherein the first failure time is the duration during which the ratio of the first actual pressure to the first demand pressure is greater than the first preset value.

[0010] Optionally, based on the condition that the ratio of the second actual pressure to the second required pressure is greater than the second preset value, after determining that there is a ventilation failure in the crankcase, the method further includes: if the second failure time is greater than the second preset time, sending a crankcase ventilation failure message notification to the user terminal, wherein the second failure time is the duration during which the ratio of the second actual pressure to the second required pressure is greater than the second preset value.

[0011] According to another aspect of the embodiments of this application, a device for determining crankcase ventilation failure is also provided. The crankcase is connected to a ventilation duct, and an oil-gas separator is provided on the ventilation duct. The device includes: a first determining unit, configured to acquire an actual temperature, a first actual pressure, and a second actual pressure, and determine an intake flow rate based on the actual temperature, the first actual pressure, and the second actual pressure. The first actual pressure is the gas pressure at the inlet of the oil-gas separator under actual operating conditions, the second actual pressure is the gas pressure at the outlet of the oil-gas separator under the actual operating conditions, and the intake flow rate is the gas pressure per unit time under the actual operating conditions. The first unit is configured to determine the intake air volume of the ventilation duct, and the actual temperature is the temperature inside the ventilation duct under the actual operating conditions; the second unit is configured to determine the first demand pressure based on the intake air volume and the first mapping relationship, wherein the first mapping relationship is the mapping relationship between the intake air volume and the first demand pressure, and the first demand pressure is the air pressure at the inlet of the oil-gas separator under normal operating conditions, wherein the normal operating conditions are the conditions under which the ventilation duct is neither detached nor leaking; the third unit is configured to determine that the crankcase has a ventilation fault when the ratio of the first actual pressure to the first demand pressure is greater than a first preset value.

[0012] According to another aspect of the embodiments of this application, a computer-readable storage medium is also provided, the computer-readable storage medium including a stored program, wherein when the program is executed by a processor, the processor executes any of the methods for determining crankcase ventilation faults described above.

[0013] According to another aspect of the embodiments of this application, a crankcase ventilation fault determination system is also provided, comprising: a controller, a crankcase, a ventilation duct, an oil-gas separator, a first pressure sensor, a second pressure sensor, and a temperature sensor. The crankcase is connected to the ventilation duct. The temperature sensor and the oil-gas separator are sequentially disposed on the ventilation duct. The first pressure sensor is disposed at the inlet of the oil-gas separator, and the second pressure sensor is disposed at the outlet of the oil-gas separator. The first pressure sensor is used to detect the air pressure at the inlet of the oil-gas separator, and the second pressure sensor is used to detect the air pressure at the outlet of the oil-gas separator. The controller is communicatively connected to the first pressure sensor, the second pressure sensor, and the temperature sensor, respectively. The controller is used to execute any of the crankcase ventilation fault determination methods described above.

[0014] In the above-mentioned method for determining crankcase ventilation failure, firstly, the actual temperature, first actual pressure, and second actual pressure are obtained, and the intake flow rate is determined based on the actual temperature, first actual pressure, and second actual pressure. The first actual pressure is the air pressure at the inlet of the oil-gas separator under actual operating conditions, the second actual pressure is the air pressure at the outlet of the oil-gas separator under actual operating conditions, the intake flow rate is the air volume of the ventilation duct per unit time under actual operating conditions, and the actual temperature is the temperature inside the ventilation duct under actual operating conditions. Then, a first demand pressure is determined based on the intake flow rate and a first mapping relationship. The first mapping relationship is the mapping relationship between the intake flow rate and the first demand pressure. The first demand pressure is the air pressure at the inlet of the oil-gas separator under normal operating conditions, where the ventilation duct is neither detached nor leaking. Finally, if the ratio of the first actual pressure to the first demand pressure is greater than a first preset value, it is determined that the crankcase has a ventilation failure. This method first determines the airflow rate of the ventilation duct using the actual temperature, a first actual pressure, and a second actual pressure. Then, based on a pre-calibrated mapping relationship between the airflow rate and the first required pressure, it determines the first required pressure at which the airflow rate is reached, i.e., the inlet pressure of the oil-gas separator under normal operating conditions. Finally, if the ratio of the inlet pressure of the oil-gas separator under actual operating conditions to the inlet pressure of the oil-gas separator under normal operating conditions is greater than a first preset value, it determines that there is a ventilation fault in the crankcase. This method determines whether there is a ventilation fault in the crankcase based on the ratio of the inlet pressure of the oil-gas separator under actual operating conditions to the inlet pressure of the oil-gas separator under normal operating conditions, without involving atmospheric pressure. Therefore, even if the ventilation duct is not completely detached or leaking (i.e., the pressure inside the crankcase ventilation duct is less than atmospheric pressure), it can still accurately determine that there is a ventilation fault in the crankcase. This method solves the problem that existing detection methods based on the difference between atmospheric pressure and the pressure inside the crankcase duct cannot accurately detect crankcase ventilation faults. Attached Figure Description

[0015] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0016] Figure 1 A flowchart is shown for a method for determining crankcase ventilation failure according to an embodiment of this application;

[0017] Figure 2 A flowchart illustrating a method for determining crankcase ventilation failure according to a specific embodiment of this application is shown;

[0018] Figure 3 A flowchart illustrating a method for determining crankcase ventilation failure according to another specific embodiment of this application is shown;

[0019] Figure 4 A flowchart is shown for a method for determining crankcase ventilation failure according to another specific embodiment of this application;

[0020] Figure 5 A flowchart is shown for a method for determining crankcase ventilation failure according to another specific embodiment of this application;

[0021] Figure 6 A flowchart illustrating a method for determining crankcase ventilation failure according to a specific embodiment of this application is shown;

[0022] Figure 7 A schematic diagram of a crankcase ventilation failure determination device according to an embodiment of this application is shown. Detailed Implementation

[0023] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0024] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0025] It should be understood that when an element (such as a layer, film, region, or substrate) is described as being "on" another element, the element may be directly on the other element, or there may be an intermediate element present. Furthermore, in the specification and claims, when an element is described as being "connected" to another element, the element may be "directly connected" to the other element, or "connected" to the other element via a third element.

[0026] As mentioned in the background section, existing detection methods based on the difference between atmospheric pressure and crankcase piping pressure cannot accurately detect crankcase ventilation faults. To address this issue, in a typical embodiment of this application, a method, apparatus, computer-readable storage medium, and system for determining crankcase ventilation faults are provided.

[0027] According to an embodiment of this application, a method for determining crankcase ventilation failure is provided. The crankcase is connected to a ventilation duct, and an oil-gas separator is installed on the ventilation duct.

[0028] Figure 1 This is a flowchart of a method for determining crankcase ventilation failure according to an embodiment of this application. Figure 1 As shown, the method includes the following steps:

[0029] Step S101: Obtain the actual temperature, the first actual pressure, and the second actual pressure, and determine the air intake flow rate based on the actual temperature, the first actual pressure, and the second actual pressure. The first actual pressure is the gas pressure at the inlet of the oil-gas separator under actual operating conditions, the second actual pressure is the gas pressure at the outlet of the oil-gas separator under actual operating conditions, the air intake flow rate is the air intake volume of the ventilation duct per unit time under actual operating conditions, and the actual temperature is the temperature inside the ventilation duct under actual operating conditions.

[0030] This application does not limit the specific process of determining the intake flow rate based on the above-mentioned actual temperature, the above-mentioned first actual pressure and the above-mentioned second actual pressure, and any feasible method is within the protection scope of this application.

[0031] In an optional implementation, step S101 above includes:

[0032] Step S1011, according to the formula The above-mentioned intake flow rate was calculated, where Mf is the intake flow rate, Ae is the diameter of the ventilation duct, Pus is the first actual pressure, R is the ideal gas constant, and T is the actual temperature. Let P be the stream function. i This is the ratio of the first actual pressure to the second actual pressure.

[0033] In the above embodiments, the real-time acquired actual temperature, first actual pressure, and second actual pressure are substituted into the formula. In this process, the intake airflow is calculated to obtain the intake airflow of the ventilation duct in real time.

[0034] Step S102: Determine the first demand pressure based on the above-mentioned air intake flow rate and the first mapping relationship. The first mapping relationship is the mapping relationship between the above-mentioned air intake flow rate and the above-mentioned first demand pressure. The first demand pressure is the above-mentioned air pressure at the inlet of the above-mentioned oil-gas separator under normal operating conditions. The above-mentioned normal operating conditions are the conditions under which the above-mentioned ventilation duct is not detached and is not leaking.

[0035] To improve the accuracy of crankcase ventilation fault detection, in one optional embodiment, before step S102 above, as follows: Figure 2As shown, the above method also includes:

[0036] Step S201: Under the above-mentioned normal operating conditions, obtain multiple intake air flow rates and corresponding first demand pressures, wherein each intake air flow rate corresponds to one of the first demand pressures.

[0037] Step S202: Determine the first mapping relationship based on all the above-mentioned intake air flow rates and the corresponding first demand pressure.

[0038] In the above embodiments, such as Figure 3 As shown, before determining the first required pressure based on the intake flow rate and the corresponding relationship table (i.e., determining the first required pressure based on the intake flow rate and the first mapping relationship), it is necessary to calculate the correspondence table between the intake flow rate and the first required pressure. To make the correspondence between the intake flow rate and the first required pressure more realistic, the intake flow rate and the corresponding first required pressure of the ventilation duct under normal operating conditions (i.e., when the ventilation duct is not detached and there is no leakage) are selected. Usually, the intake flow rate and the first required pressure corresponding to multiple commonly used operating points of the engine under normal operating conditions are selected. Each operating point corresponds to one intake flow rate and one first required pressure. Then, a two-dimensional relationship table between the intake flow rate and the first required pressure is formed based on the selected operating point and the corresponding intake flow rate and the first required pressure. Furthermore, to ensure the accuracy of the correspondence between the intake flow rate and the first required pressure, a large number of intake flow rates and corresponding first required pressures need to be selected, thereby ensuring the accuracy of the first required pressure determined based on the intake flow rate, and thus ensuring the accuracy of the ratio of the first actual pressure to the first required pressure, thereby improving the accuracy of crankcase ventilation fault detection.

[0039] It should be noted that the first required pressure mentioned above is the gas pressure that the inlet of the oil-gas separator needs to reach when the first intake flow rate is achieved under normal operating conditions.

[0040] Step S103: If the ratio of the first actual pressure to the first required pressure is greater than the first preset value, it is determined that there is a ventilation failure in the crankcase.

[0041] To further improve the accuracy of crankcase ventilation fault detection, in another optional embodiment, based on the situation where the ratio of the first actual pressure to the first required pressure is greater than the first preset value, after step S103, as follows: Figure 3 As shown, the above method also includes:

[0042] Step S301: If the first fault time is greater than the first preset time, a crankcase ventilation fault message notification is sent to the user terminal. The first fault time is the duration during which the ratio of the first actual pressure to the first demand pressure is greater than the first preset value.

[0043] In the above embodiments, such as Figure 3 As shown, when the ratio of the first actual pressure to the first demand pressure is greater than the first preset value Q1, it can be determined that there is a crankcase ventilation fault. However, in order to avoid randomness, a crankcase ventilation fault notification is sent to the user terminal only when the duration of the first fault time, i.e., the ratio of the first actual pressure to the first demand pressure being greater than the first preset value Q1, is greater than the first preset time T1. This avoids random situations and improves the accuracy of crankcase ventilation fault detection.

[0044] To further improve the accuracy of crankcase ventilation fault detection, in another optional embodiment, after step S1011 above, as follows: Figure 4 As shown, the above method also includes:

[0045] Step S401: Determine the second demand pressure based on the above-mentioned air intake flow rate and the second mapping relationship. The second demand pressure is the gas pressure at the outlet of the oil-gas separator under the above-mentioned normal operating conditions. The second mapping relationship is the mapping relationship between the above-mentioned air intake flow rate and the above-mentioned second demand pressure.

[0046] Step S402: If the ratio of the second actual pressure to the second required pressure is greater than the second preset value, it is determined that the crankcase has the aforementioned ventilation failure.

[0047] In the above embodiments, when the ratio of the second actual pressure to the second required pressure is greater than the second preset value, it can also be determined that there is a ventilation fault in the crankcase. That is, as long as either the ratio of the first actual pressure to the first required pressure is greater than the first preset value or the ratio of the second actual pressure to the second required pressure is greater than the second preset value, it can be determined that there is a ventilation fault in the crankcase, thereby improving the accuracy of crankcase ventilation fault detection.

[0048] It should be noted that, taking into account the pressure loss caused by the resistance of the oil-gas separator, the first preset value is set to be greater than the second preset value.

[0049] To further improve the accuracy of crankcase ventilation fault detection, in another optional embodiment, before step S401 above, as follows: Figure 5 As shown, the above method also includes:

[0050] Step S501: Under the above-mentioned normal operating conditions, obtain multiple intake air flow rates and corresponding second demand pressures, with each intake air flow rate corresponding to the second demand pressure.

[0051] Step S502: Determine the second mapping relationship based on all the above-mentioned intake air flow rates and the corresponding second demand pressures.

[0052] In the above embodiments, such as Figure 6 As shown, before determining the second demand pressure based on the intake flow rate and the corresponding relationship table, i.e., before determining the second demand pressure based on the intake flow rate and the second mapping relationship, it is necessary to calculate the correspondence table between the intake flow rate and the second demand pressure. In order to make the correspondence between the intake flow rate and the second demand pressure more realistic, the intake flow rate and the corresponding second demand pressure of the ventilation duct under normal operating conditions, i.e., the ventilation duct is not detached and there is no leakage, are selected. Usually, the intake flow rate and the second demand pressure corresponding to multiple commonly used operating points of the engine under normal operating conditions are selected. Each operating point corresponds to one intake flow rate and one second demand pressure. Then, a two-dimensional relationship table between the intake flow rate and the second demand pressure is formed based on the intake flow rate and the second demand pressure corresponding to the selected operating points. Furthermore, in order to ensure the accuracy of the correspondence between the intake flow rate and the second demand pressure, a large number of intake flow rates and corresponding second demand pressures need to be selected to ensure the accuracy of the second demand pressure determined based on the intake flow rate, thereby ensuring the accuracy of the ratio of the second actual pressure and the second demand pressure, and thus improving the accuracy of crankcase ventilation fault detection.

[0053] It should be noted that the second demand pressure mentioned above is the gas pressure that the oil-gas separator outlet needs to reach when the second intake flow rate is reached under normal operating conditions.

[0054] To further improve the accuracy of crankcase ventilation fault detection, in an optional embodiment, based on the condition that the ratio of the second actual pressure to the second required pressure is greater than the second preset value, after step S402, the method further includes:

[0055] Step S601: If the second fault time is greater than the second preset time, a crankcase ventilation fault message notification is sent to the user terminal. The second fault time is the duration during which the ratio of the second actual pressure to the second required pressure is greater than the second preset value.

[0056] In the above embodiments, such as Figure 5 As shown, when the ratio of the second actual pressure to the second demand pressure is greater than the second preset value Q2, it can be determined that there is a crankcase ventilation fault. However, in order to avoid randomness, a crankcase ventilation fault notification is sent to the user terminal only when the duration of the second fault time, i.e., the ratio of the second actual pressure to the second demand pressure being greater than the second preset value Q2, is greater than the second preset time T2. This avoids random situations and improves the accuracy of crankcase ventilation fault detection.

[0057] In the above-mentioned method for determining crankcase ventilation failure, firstly, the actual temperature, first actual pressure, and second actual pressure are obtained, and the intake flow rate is determined based on the actual temperature, first actual pressure, and second actual pressure. The first actual pressure is the air pressure at the inlet of the oil-gas separator under actual operating conditions, the second actual pressure is the air pressure at the outlet of the oil-gas separator under actual operating conditions, the intake flow rate is the air volume of the ventilation duct per unit time under actual operating conditions, and the actual temperature is the temperature inside the ventilation duct under actual operating conditions. Then, a first demand pressure is determined based on the intake flow rate and a first mapping relationship. The first mapping relationship is the mapping relationship between the intake flow rate and the first demand pressure. The first demand pressure is the air pressure at the inlet of the oil-gas separator under normal operating conditions, where the ventilation duct is neither detached nor leaking. Finally, if the ratio of the first actual pressure to the first demand pressure is greater than a first preset value, it is determined that the crankcase has a ventilation failure. This method first determines the airflow rate of the ventilation duct using the actual temperature, a first actual pressure, and a second actual pressure. Then, based on a pre-calibrated mapping relationship between the airflow rate and the first required pressure, it determines the first required pressure at which the airflow rate is reached, i.e., the inlet pressure of the oil-gas separator under normal operating conditions. Finally, if the ratio of the inlet pressure of the oil-gas separator under actual operating conditions to the inlet pressure of the oil-gas separator under normal operating conditions is greater than a first preset value, it determines that there is a ventilation fault in the crankcase. This method determines whether there is a ventilation fault in the crankcase based on the ratio of the inlet pressure of the oil-gas separator under actual operating conditions to the inlet pressure of the oil-gas separator under normal operating conditions, without involving atmospheric pressure. Therefore, even if the ventilation duct is not completely detached or leaking (i.e., the pressure inside the crankcase ventilation duct is less than atmospheric pressure), it can still accurately determine that there is a ventilation fault in the crankcase. This method solves the problem that existing detection methods based on the difference between atmospheric pressure and the pressure inside the crankcase duct cannot accurately detect crankcase ventilation faults.

[0058] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0059] This application also provides a device for determining crankcase ventilation faults. It should be noted that this device can be used to execute the method for determining crankcase ventilation faults provided in this application. The following describes the device for determining crankcase ventilation faults provided in this application.

[0060] Figure 7 This is a schematic diagram of a crankcase ventilation fault determination device according to an embodiment of this application. Figure 7 As shown, the device includes:

[0061] The first determining unit 10 is used to acquire the actual temperature, the first actual pressure and the second actual pressure, and to determine the air intake flow rate based on the actual temperature, the first actual pressure and the second actual pressure. The first actual pressure is the air pressure at the inlet of the oil-gas separator under actual operating conditions, the second actual pressure is the air pressure at the outlet of the oil-gas separator under actual operating conditions, the air intake flow rate is the air intake volume of the ventilation duct per unit time under actual operating conditions, and the actual temperature is the temperature inside the ventilation duct under actual operating conditions.

[0062] This application does not limit the specific process of determining the intake flow rate based on the above-mentioned actual temperature, the above-mentioned first actual pressure and the above-mentioned second actual pressure, and any feasible method is within the protection scope of this application.

[0063] In one optional implementation, the determining unit includes:

[0064] The calculation module is used to calculate based on the formula. The above-mentioned intake flow rate was calculated, where Mf is the intake flow rate, Ae is the diameter of the ventilation duct, Pus is the first actual pressure, R is the ideal gas constant, T is the actual temperature, and φ(P) is the pressure of the first actual pressure. i ) is the stream function, P i This is the ratio of the first actual pressure to the second actual pressure.

[0065] In the above embodiments, the real-time acquired actual temperature, first actual pressure, and second actual pressure are substituted into the formula. In this process, the intake airflow is calculated to obtain the intake airflow of the ventilation duct in real time.

[0066] The second determining unit 20 is used to determine the first demand pressure based on the above-mentioned air intake flow rate and the first mapping relationship. The first mapping relationship is the mapping relationship between the above-mentioned air intake flow rate and the above-mentioned first demand pressure. The first demand pressure is the air pressure at the inlet of the above-mentioned oil-gas separator under normal operating conditions. The above-mentioned normal operating conditions are the conditions under which the above-mentioned ventilation duct is not detached and is not leaking.

[0067] To improve the accuracy of crankcase ventilation fault detection, in one optional embodiment, the above-mentioned device further includes:

[0068] The first acquisition unit is used to acquire multiple intake air flow rates and corresponding first demand pressures under the above-mentioned normal operating conditions, wherein the intake air flow rate and the first demand pressure correspond one-to-one.

[0069] The fourth determining unit is used to determine the first mapping relationship based on all the above-mentioned intake air flow rates and the corresponding first demand pressure.

[0070] In the above embodiments, such as Figure 3 As shown, before determining the first required pressure based on the intake flow rate and the corresponding relationship table (i.e., determining the first required pressure based on the intake flow rate and the first mapping relationship), it is necessary to calculate the correspondence table between the intake flow rate and the first required pressure. To make the correspondence between the intake flow rate and the first required pressure more realistic, the intake flow rate and the corresponding first required pressure of the ventilation duct under normal operating conditions (i.e., when the ventilation duct is not detached and there is no leakage) are selected. Usually, the intake flow rate and the first required pressure corresponding to multiple commonly used operating points of the engine under normal operating conditions are selected. Each operating point corresponds to one intake flow rate and one first required pressure. Then, a two-dimensional relationship table between the intake flow rate and the first required pressure is formed based on the selected operating point and the corresponding intake flow rate and the first required pressure. Furthermore, to ensure the accuracy of the correspondence between the intake flow rate and the first required pressure, a large number of intake flow rates and corresponding first required pressures need to be selected, thereby ensuring the accuracy of the first required pressure determined based on the intake flow rate, and thus ensuring the accuracy of the ratio of the first actual pressure to the first required pressure, thereby improving the accuracy of crankcase ventilation fault detection.

[0071] It should be noted that the first required pressure mentioned above is the gas pressure that the inlet of the oil-gas separator needs to reach when the first intake flow rate is achieved under normal operating conditions.

[0072] The third determining unit 30 is used to determine that the crankcase has a ventilation failure when the ratio of the first actual pressure to the first required pressure is greater than a first preset value.

[0073] To further improve the accuracy of crankcase ventilation fault detection, in another optional embodiment, based on the condition that the ratio of the first actual pressure to the first required pressure is greater than the first preset value, the device further includes:

[0074] The first sending unit is configured to send a crankcase ventilation fault notification to the user terminal when the first fault time is greater than the first preset time, wherein the first fault time is the duration during which the ratio of the first actual pressure to the first demand pressure is greater than the first preset value.

[0075] In the above embodiments, such as Figure 3As shown, when the ratio of the first actual pressure to the first demand pressure is greater than the first preset value Q1, it can be determined that there is a crankcase ventilation fault. However, in order to avoid randomness, a crankcase ventilation fault notification is sent to the user terminal only when the duration of the first fault time, i.e., the ratio of the first actual pressure to the first demand pressure being greater than the first preset value Q1, is greater than the first preset time T1. This avoids random situations and improves the accuracy of crankcase ventilation fault detection.

[0076] To further improve the accuracy of crankcase ventilation fault detection, in another optional embodiment, the above-mentioned device further includes:

[0077] The fifth determining unit is used to determine the second demand pressure based on the above-mentioned air intake flow rate and the second mapping relationship. The second demand pressure is the gas pressure at the outlet of the oil-gas separator under the above-mentioned normal operating conditions. The second mapping relationship is the mapping relationship between the above-mentioned air intake flow rate and the above-mentioned second demand pressure.

[0078] The sixth determining unit is used to determine that the crankcase has the aforementioned ventilation failure when the ratio of the second actual pressure to the second required pressure is greater than a second preset value.

[0079] In the above embodiments, when the ratio of the second actual pressure to the second required pressure is greater than the second preset value, it can also be determined that there is a ventilation fault in the crankcase. That is, as long as either the ratio of the first actual pressure to the first required pressure is greater than the first preset value or the ratio of the second actual pressure to the second required pressure is greater than the second preset value, it can be determined that there is a ventilation fault in the crankcase, thereby improving the accuracy of crankcase ventilation fault detection.

[0080] It should be noted that, taking into account the pressure loss caused by the resistance of the oil-gas separator, the first preset value is set to be greater than the second preset value.

[0081] To further improve the accuracy of crankcase ventilation fault detection, in another optional embodiment, the above-mentioned device further includes:

[0082] The second acquisition unit is used to acquire multiple intake air flow rates and corresponding second demand pressures under the above-mentioned normal operating conditions, wherein the intake air flow rate and the second demand pressure correspond one-to-one.

[0083] The seventh determining unit is used to determine the second mapping relationship based on all the above-mentioned intake flow rates and the corresponding second demand pressure.

[0084] In the above embodiments, such as Figure 6As shown, before determining the second demand pressure based on the intake flow rate and the corresponding relationship table, i.e., before determining the second demand pressure based on the intake flow rate and the second mapping relationship, it is necessary to calculate the correspondence table between the intake flow rate and the second demand pressure. In order to make the correspondence between the intake flow rate and the second demand pressure more realistic, the intake flow rate and the corresponding second demand pressure of the ventilation duct under normal operating conditions, i.e., the ventilation duct is not detached and there is no leakage, are selected. Usually, the intake flow rate and the second demand pressure corresponding to multiple commonly used operating points of the engine under normal operating conditions are selected. Each operating point corresponds to one intake flow rate and one second demand pressure. Then, a two-dimensional relationship table between the intake flow rate and the second demand pressure is formed based on the intake flow rate and the second demand pressure corresponding to the selected operating points. Furthermore, in order to ensure the accuracy of the correspondence between the intake flow rate and the second demand pressure, a large number of intake flow rates and corresponding second demand pressures need to be selected to ensure the accuracy of the second demand pressure determined based on the intake flow rate, thereby ensuring the accuracy of the ratio of the second actual pressure and the second demand pressure, and thus improving the accuracy of crankcase ventilation fault detection.

[0085] It should be noted that the second demand pressure mentioned above is the gas pressure that the oil-gas separator outlet needs to reach when the second intake flow rate is reached under normal operating conditions.

[0086] To further improve the accuracy of crankcase ventilation fault detection, in an optional embodiment, based on the condition that the ratio of the second actual pressure to the second required pressure is greater than the second preset value, the device further includes:

[0087] The second sending unit is used to send a crankcase ventilation fault notification to the user terminal when the second fault time is greater than the second preset time. The second fault time is the duration during which the ratio of the second actual pressure to the second required pressure is greater than the second preset value.

[0088] In the above embodiments, such as Figure 5 As shown, when the ratio of the second actual pressure to the second demand pressure is greater than the second preset value Q2, it can be determined that there is a crankcase ventilation fault. However, in order to avoid randomness, a crankcase ventilation fault notification is sent to the user terminal only when the duration of the second fault time, i.e., the ratio of the second actual pressure to the second demand pressure being greater than the second preset value Q2, is greater than the second preset time T2. This avoids random situations and improves the accuracy of crankcase ventilation fault detection.

[0089] In the aforementioned crankcase ventilation fault determination device, the first determination unit is used to acquire the actual temperature, the first actual pressure, and the second actual pressure, and determine the intake flow rate based on the actual temperature, the first actual pressure, and the second actual pressure. The first actual pressure is the air pressure at the inlet of the oil-gas separator under actual operating conditions, the second actual pressure is the air pressure at the outlet of the oil-gas separator under actual operating conditions, the intake flow rate is the air volume of the ventilation duct per unit time under actual operating conditions, and the actual temperature is the temperature inside the ventilation duct under actual operating conditions. The second determination unit is used to determine the first demand pressure based on the intake flow rate and a first mapping relationship. The first mapping relationship is the mapping relationship between the intake flow rate and the first demand pressure. The first demand pressure is the air pressure at the inlet of the oil-gas separator under normal operating conditions, where the ventilation duct is neither detached nor leaking. The third determination unit is used to determine that the crankcase has a ventilation fault when the ratio of the first actual pressure to the first demand pressure is greater than a first preset value. The device first determines the airflow rate of the ventilation duct using the actual temperature, a first actual pressure, and a second actual pressure. Then, based on a pre-calibrated mapping relationship between the airflow rate and the first required pressure, it determines the first required pressure at which the airflow rate is reached, i.e., the inlet pressure of the oil-gas separator under normal operating conditions. Finally, if the ratio of the inlet pressure of the oil-gas separator under actual operating conditions to the inlet pressure of the oil-gas separator under normal operating conditions is greater than a first preset value, it determines that there is a ventilation fault in the crankcase. This device determines whether there is a ventilation fault in the crankcase based on the ratio of the inlet pressure of the oil-gas separator under actual operating conditions to the inlet pressure of the oil-gas separator under normal operating conditions, without involving atmospheric pressure. Therefore, even if the ventilation duct is not completely detached or leaking (i.e., the pressure inside the crankcase ventilation duct is less than atmospheric pressure), it can still accurately determine that there is a ventilation fault in the crankcase. This device solves the problem that existing detection methods based on the difference between atmospheric pressure and the pressure inside the crankcase duct cannot accurately detect crankcase ventilation faults.

[0090] The aforementioned crankcase ventilation fault determination device includes a processor and a memory. The first determination unit, the second determination unit, and the third determination unit are all stored in the memory as program units, and the processor executes the aforementioned program units stored in the memory to achieve the corresponding functions.

[0091] The processor contains a kernel, which retrieves the corresponding program unit from memory. One or more kernels can be configured, and adjusting kernel parameters can address the problem that existing methods based on the difference between atmospheric pressure and crankcase piping pressure cannot accurately detect crankcase ventilation faults.

[0092] The memory may include non-permanent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0093] This application provides a computer-readable storage medium including a stored program, wherein when the program is executed by a processor, the processor executes the method for determining crankcase ventilation faults.

[0094] This application provides a system for determining crankcase ventilation faults, including: a controller, a crankcase, a ventilation duct, an oil-gas separator, a first pressure sensor, a second pressure sensor, and a temperature sensor. The crankcase is connected to the ventilation duct. The temperature sensor and the oil-gas separator are sequentially arranged on the ventilation duct. The first pressure sensor is located at the inlet of the oil-gas separator, and the second pressure sensor is located at the outlet of the oil-gas separator. The first pressure sensor is used to detect the air pressure at the inlet of the oil-gas separator, and the second pressure sensor is used to detect the air pressure at the outlet of the oil-gas separator. The controller is communicatively connected to the first pressure sensor, the second pressure sensor, and the temperature sensor, respectively. The controller is used to execute the method for determining crankcase ventilation faults.

[0095] In the above embodiment, the crankcase ventilation fault determination system includes: a controller, a crankcase, a ventilation duct, an oil-gas separator, a first pressure sensor, a second pressure sensor, and a temperature sensor. The crankcase is connected to the ventilation duct. The temperature sensor and the oil-gas separator are sequentially arranged on the ventilation duct. The first pressure sensor is located at the inlet of the oil-gas separator, and the second pressure sensor is located at the outlet of the oil-gas separator. The first pressure sensor is used to detect the air pressure at the inlet of the oil-gas separator, and the second pressure sensor is used to detect the air pressure at the outlet of the oil-gas separator. The controller is communicatively connected to the first pressure sensor, the second pressure sensor, and the temperature sensor, respectively. The controller is used to execute the crankcase ventilation fault determination method. The system's controller first determines the intake flow rate of the ventilation duct using the actual temperature obtained by a temperature sensor, the first actual pressure obtained by a first pressure sensor, and the second actual pressure obtained by a second pressure sensor. Then, based on a pre-calibrated mapping relationship between the intake flow rate and the first required pressure, it determines the first required pressure at which the intake flow rate is reached, i.e., the inlet pressure of the oil-gas separator under normal operating conditions. Finally, if the ratio of the inlet pressure of the oil-gas separator under actual operating conditions to the inlet pressure of the oil-gas separator under normal operating conditions is greater than a first preset value, it determines that there is a ventilation fault in the crankcase. This system determines whether there is a ventilation fault in the crankcase based on the ratio of the inlet pressure of the oil-gas separator under actual operating conditions to the inlet pressure of the oil-gas separator under normal operating conditions, without involving atmospheric pressure. Therefore, even if the ventilation duct is not completely detached or leaking (i.e., the pressure inside the crankcase ventilation duct is less than atmospheric pressure), it can still accurately determine that there is a ventilation fault in the crankcase. This system solves the problem that existing detection methods based on the difference between atmospheric pressure and the pressure inside the crankcase duct cannot accurately detect crankcase ventilation faults.

[0096] This application provides a device, which includes a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, it performs at least the following steps:

[0097] Step S101: Obtain the actual temperature, the first actual pressure, and the second actual pressure, and determine the air intake flow rate based on the actual temperature, the first actual pressure, and the second actual pressure. The first actual pressure is the gas pressure at the inlet of the oil-gas separator under actual operating conditions, the second actual pressure is the gas pressure at the outlet of the oil-gas separator under actual operating conditions, the air intake flow rate is the air intake volume of the ventilation duct per unit time under actual operating conditions, and the actual temperature is the temperature inside the ventilation duct under actual operating conditions.

[0098] Step S102: Determine the first demand pressure based on the above-mentioned air intake flow rate and the first mapping relationship. The first mapping relationship is the mapping relationship between the above-mentioned air intake flow rate and the above-mentioned first demand pressure. The first demand pressure is the above-mentioned air pressure at the inlet of the above-mentioned oil-gas separator under normal operating conditions. The above-mentioned normal operating conditions are the conditions under which the above-mentioned ventilation duct is not detached and is not leaking.

[0099] Step S103: If the ratio of the first actual pressure to the first required pressure is greater than the first preset value, it is determined that there is a ventilation failure in the crankcase.

[0100] The devices mentioned in this article can be servers, PCs, tablets, mobile phones, etc.

[0101] This application also provides a computer program product, which, when executed on a data processing device, is suitable for executing an initialization program having at least the following method steps:

[0102] Step S101: Obtain the actual temperature, the first actual pressure, and the second actual pressure, and determine the air intake flow rate based on the actual temperature, the first actual pressure, and the second actual pressure. The first actual pressure is the gas pressure at the inlet of the oil-gas separator under actual operating conditions, the second actual pressure is the gas pressure at the outlet of the oil-gas separator under actual operating conditions, the air intake flow rate is the air intake volume of the ventilation duct per unit time under actual operating conditions, and the actual temperature is the temperature inside the ventilation duct under actual operating conditions.

[0103] Step S102: Determine the first demand pressure based on the above-mentioned air intake flow rate and the first mapping relationship. The first mapping relationship is the mapping relationship between the above-mentioned air intake flow rate and the above-mentioned first demand pressure. The first demand pressure is the above-mentioned air pressure at the inlet of the above-mentioned oil-gas separator under normal operating conditions. The above-mentioned normal operating conditions are the conditions under which the above-mentioned ventilation duct is not detached and is not leaking.

[0104] Step S103: If the ratio of the first actual pressure to the first required pressure is greater than the first preset value, it is determined that there is a ventilation failure in the crankcase.

[0105] In the above embodiments of this application, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0106] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units described above can be a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0107] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0108] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0109] If the aforementioned integrated units are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a computer-readable storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned computer-readable storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0110] As can be seen from the above description, the embodiments of this application achieve the following technical effects:

[0111] 1) In the method for determining crankcase ventilation failure of this application, firstly, the actual temperature, the first actual pressure, and the second actual pressure are obtained, and the intake flow rate is determined based on the actual temperature, the first actual pressure, and the second actual pressure. The first actual pressure is the air pressure at the inlet of the oil-gas separator under actual operating conditions, the second actual pressure is the air pressure at the outlet of the oil-gas separator under actual operating conditions, the intake flow rate is the air volume of the ventilation duct per unit time under actual operating conditions, and the actual temperature is the temperature inside the ventilation duct under actual operating conditions. Then, a first demand pressure is determined based on the intake flow rate and a first mapping relationship. The first mapping relationship is the mapping relationship between the intake flow rate and the first demand pressure. The first demand pressure is the air pressure at the inlet of the oil-gas separator under normal operating conditions, where the ventilation duct is neither detached nor leaking. Finally, if the ratio of the first actual pressure to the first demand pressure is greater than a first preset value, it is determined that the crankcase has a ventilation failure. This method first determines the airflow rate of the ventilation duct using the actual temperature, a first actual pressure, and a second actual pressure. Then, based on a pre-calibrated mapping relationship between the airflow rate and the first required pressure, it determines the first required pressure at which the airflow rate is reached, i.e., the inlet pressure of the oil-gas separator under normal operating conditions. Finally, if the ratio of the inlet pressure of the oil-gas separator under actual operating conditions to the inlet pressure of the oil-gas separator under normal operating conditions is greater than a first preset value, it determines that there is a ventilation fault in the crankcase. This method determines whether there is a ventilation fault in the crankcase based on the ratio of the inlet pressure of the oil-gas separator under actual operating conditions to the inlet pressure of the oil-gas separator under normal operating conditions, without involving atmospheric pressure. Therefore, even if the ventilation duct is not completely detached or leaking (i.e., the pressure inside the crankcase ventilation duct is less than atmospheric pressure), it can still accurately determine that there is a ventilation fault in the crankcase. This method solves the problem that existing detection methods based on the difference between atmospheric pressure and the pressure inside the crankcase duct cannot accurately detect crankcase ventilation faults.

[0112] 2) In the crankcase ventilation fault determination device of this application, the first determination unit is used to acquire the actual temperature, the first actual pressure and the second actual pressure, and determine the intake flow rate based on the actual temperature, the first actual pressure and the second actual pressure. The first actual pressure is the air pressure at the inlet of the oil-gas separator under actual operating conditions, the second actual pressure is the air pressure at the outlet of the oil-gas separator under actual operating conditions, the intake flow rate is the air volume of the ventilation duct per unit time under actual operating conditions, and the actual temperature is the temperature inside the ventilation duct under actual operating conditions. The second determination unit is used to determine the first demand pressure based on the intake flow rate and the first mapping relationship. The first mapping relationship is the mapping relationship between the intake flow rate and the first demand pressure. The first demand pressure is the air pressure at the inlet of the oil-gas separator under normal operating conditions. The normal operating conditions are the conditions where the ventilation duct is not detached and does not leak. The third determination unit is used to determine that the crankcase has a ventilation fault when the ratio of the first actual pressure to the first demand pressure is greater than a first preset value. The device first determines the airflow rate of the ventilation duct using the actual temperature, a first actual pressure, and a second actual pressure. Then, based on a pre-calibrated mapping relationship between the airflow rate and the first required pressure, it determines the first required pressure at which the airflow rate is reached, i.e., the inlet pressure of the oil-gas separator under normal operating conditions. Finally, if the ratio of the inlet pressure of the oil-gas separator under actual operating conditions to the inlet pressure of the oil-gas separator under normal operating conditions is greater than a first preset value, it determines that there is a ventilation fault in the crankcase. This device determines whether there is a ventilation fault in the crankcase based on the ratio of the inlet pressure of the oil-gas separator under actual operating conditions to the inlet pressure of the oil-gas separator under normal operating conditions, without involving atmospheric pressure. Therefore, even if the ventilation duct is not completely detached or leaking (i.e., the pressure inside the crankcase ventilation duct is less than atmospheric pressure), it can still accurately determine that there is a ventilation fault in the crankcase. This device solves the problem that existing detection methods based on the difference between atmospheric pressure and the pressure inside the crankcase duct cannot accurately detect crankcase ventilation faults.

[0113] 3) The crankcase ventilation fault determination system of this application includes: a controller, a crankcase, a ventilation duct, an oil-gas separator, a first pressure sensor, a second pressure sensor, and a temperature sensor. The crankcase is connected to the ventilation duct. The temperature sensor and the oil-gas separator are sequentially arranged on the ventilation duct. The first pressure sensor is located at the inlet of the oil-gas separator, and the second pressure sensor is located at the outlet of the oil-gas separator. The first pressure sensor is used to detect the air pressure at the inlet of the oil-gas separator, and the second pressure sensor is used to detect the air pressure at the outlet of the oil-gas separator. The controller is communicatively connected to the first pressure sensor, the second pressure sensor, and the temperature sensor, respectively. The controller is used to execute the crankcase ventilation fault determination method. The system's controller first determines the intake flow rate of the ventilation duct using the actual temperature obtained by a temperature sensor, the first actual pressure obtained by a first pressure sensor, and the second actual pressure obtained by a second pressure sensor. Then, based on a pre-calibrated mapping relationship between the intake flow rate and the first required pressure, it determines the first required pressure at which the intake flow rate is reached, i.e., the inlet pressure of the oil-gas separator under normal operating conditions. Finally, if the ratio of the inlet pressure of the oil-gas separator under actual operating conditions to the inlet pressure of the oil-gas separator under normal operating conditions is greater than a first preset value, it determines that there is a ventilation fault in the crankcase. This system determines whether there is a ventilation fault in the crankcase based on the ratio of the inlet pressure of the oil-gas separator under actual operating conditions to the inlet pressure of the oil-gas separator under normal operating conditions, without involving atmospheric pressure. Therefore, even if the ventilation duct is not completely detached or leaking (i.e., the pressure inside the crankcase ventilation duct is less than atmospheric pressure), it can still accurately determine that there is a ventilation fault in the crankcase. This system solves the problem that existing detection methods based on the difference between atmospheric pressure and the pressure inside the crankcase duct cannot accurately detect crankcase ventilation faults.

[0114] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for determining crankcase ventilation failure, characterized in that, The crankcase is connected to a ventilation duct, and an oil-gas separator is installed on the ventilation duct. The method includes: The actual temperature, first actual pressure, and second actual pressure are obtained, and the air intake flow rate is determined based on the actual temperature, first actual pressure, and second actual pressure. The first actual pressure is the gas pressure at the inlet of the oil-gas separator under actual operating conditions, the second actual pressure is the gas pressure at the outlet of the oil-gas separator under actual operating conditions, the air intake flow rate is the amount of air entering the ventilation duct per unit time under actual operating conditions, and the actual temperature is the temperature inside the ventilation duct under actual operating conditions. The first demand pressure is determined based on the air intake flow rate and the first mapping relationship. The first mapping relationship is the mapping relationship between the air intake flow rate and the first demand pressure. The first demand pressure is the air pressure at the inlet of the oil-gas separator under normal operating conditions. The normal operating conditions are the conditions under which the ventilation duct is neither detached nor leaking. If the ratio of the first actual pressure to the first required pressure is greater than a first preset value, it is determined that the crankcase has a ventilation failure. Determining the intake flow rate based on the actual temperature, the first actual pressure, and the second actual pressure includes: according to the formula The intake air flow rate is calculated, where Mf is the intake air flow rate, Ae is the diameter of the ventilation duct, Pus is the first actual pressure, R is the ideal gas constant, and T is the actual temperature. (P) i ) is the stream function, P i It is the ratio of the first actual pressure to the second actual pressure.

2. The determination method according to claim 1, characterized in that, Before determining the first demand pressure based on the intake flow rate and the first mapping relationship, the method further includes: Under normal operating conditions, multiple intake air flow rates and corresponding first demand pressures are obtained, with each intake air flow rate corresponding to a first demand pressure. The first mapping relationship is determined based on all the intake airflow rates and the corresponding first demand pressure.

3. The determination method according to claim 1, characterized in that, According to the formula After calculating the intake air flow rate, the method further includes: Based on the air intake flow rate and the second mapping relationship, the second demand pressure is determined. The second demand pressure is the gas pressure at the outlet of the oil-gas separator under normal operating conditions. The second mapping relationship is the mapping relationship between the air intake flow rate and the second demand pressure. If the ratio of the second actual pressure to the second required pressure is greater than the second preset value, it is determined that the crankcase has the ventilation fault.

4. The determination method according to claim 3, characterized in that, Before determining the second demand pressure based on the intake flow rate and the second mapping relationship, the method further includes: Under the normal operating conditions, multiple intake air flow rates and corresponding second demand pressures are obtained, with each intake air flow rate corresponding to a one-to-one second demand pressure. The second mapping relationship is determined based on all the said intake air flow rates and the corresponding second demand pressure.

5. The determination method according to claim 1, characterized in that, Based on the condition that the ratio of the first actual pressure to the first required pressure is greater than the first preset value, after determining that there is a ventilation fault in the crankcase, the method further includes: If the first fault time is longer than the first preset time, a crankcase ventilation fault message is sent to the user terminal. The first fault time is the duration during which the ratio of the first actual pressure to the first required pressure is greater than the first preset value.

6. The determining method according to claim 3, characterized in that, Based on the condition that the ratio of the second actual pressure to the second required pressure is greater than the second preset value, after determining that there is a ventilation failure in the crankcase, the method further includes: If the second fault time is longer than the second preset time, a crankcase ventilation fault message is sent to the user terminal. The second fault time is the duration during which the ratio of the second actual pressure to the second required pressure is greater than the second preset value.

7. A device for determining crankcase ventilation failure, characterized in that, The crankcase is connected to a ventilation duct, and an oil-gas separator is installed on the ventilation duct. The device includes: The first determining unit is used to acquire the actual temperature, the first actual pressure, and the second actual pressure, and to determine the air intake flow rate based on the actual temperature, the first actual pressure, and the second actual pressure. The first actual pressure is the gas pressure at the inlet of the oil-gas separator under actual operating conditions, the second actual pressure is the gas pressure at the outlet of the oil-gas separator under actual operating conditions, the air intake flow rate is the amount of air entering the ventilation duct per unit time under actual operating conditions, and the actual temperature is the temperature inside the ventilation duct under actual operating conditions. The second determining unit is used to determine the first demand pressure based on the air intake flow rate and the first mapping relationship. The first mapping relationship is the mapping relationship between the air intake flow rate and the first demand pressure. The first demand pressure is the air pressure at the inlet of the oil-gas separator under normal operating conditions. The normal operating conditions are the conditions under which the ventilation duct is neither detached nor leaking. The third determining unit is used to determine that the crankcase has a ventilation failure when the ratio of the first actual pressure to the first required pressure is greater than a first preset value. The determining unit includes: a calculation module, used to calculate according to the formula The intake air flow rate is calculated, where Mf is the intake air flow rate, Ae is the diameter of the ventilation duct, Pus is the first actual pressure, R is the ideal gas constant, and T is the actual temperature. (P) i ) is the stream function, P i It is the ratio of the first actual pressure to the second actual pressure.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored program, wherein when the program is executed by a processor, the processor performs the method for determining crankcase ventilation failure as described in any one of claims 1 to 6.

9. A system for determining crankcase ventilation faults, characterized in that, include: The system comprises a controller, a crankcase, a ventilation duct, an oil-gas separator, a first pressure sensor, a second pressure sensor, and a temperature sensor. The crankcase is connected to the ventilation duct. The temperature sensor and the oil-gas separator are sequentially mounted on the ventilation duct. The first pressure sensor is located at the inlet of the oil-gas separator, and the second pressure sensor is located at the outlet of the oil-gas separator. The first pressure sensor is used to detect the air pressure at the inlet of the oil-gas separator, and the second pressure sensor is used to detect the air pressure at the outlet of the oil-gas separator. The controller is communicatively connected to the first pressure sensor, the second pressure sensor, and the temperature sensor, respectively. The controller is used to execute the crankcase ventilation fault determination method according to any one of claims 1 to 6.

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