Monitoring method of crankcase ventilation system and crankcase ventilation system

Abstract

The present application provides a monitoring method for a crankcase ventilation system and a crankcase ventilation system. The crankcase ventilation system includes a crankcase assembly, an air-assisted oil-gas separator, a supercharger assembly, an intake manifold, and an external air source assembly. The crankcase assembly, the air-assisted oil-gas separator, the supercharger assembly, and the intake manifold form a circuit, and the external air source assembly is connected to the air-assisted oil-gas separator and provides a stable air source. While the crankcase ventilation system utilizes the external air source assembly to obtain high-efficiency oil-gas separation efficiency, it monitors the state of the crankcase ventilation system pipeline, the working state of the air-assisted oil-gas separator, and the emulsified state of the engine oil by obtaining the parameter value of the air-assisted oil-gas separator.

Description

Technical Field

[0001] The present application relates to the technical field of crankcase ventilation systems, and in particular to a monitoring method for a crankcase ventilation system and a crankcase ventilation system. Background Art

[0002] When the engine is working, the high-pressure combustible mixture and burned gas in the combustion chamber will more or less leak into the crankcase through the gap between the piston group and the cylinder, causing blowby. The components of blowby are unburned fuel gas, water vapor and exhaust gas, which will dilute the engine oil, reduce the performance of the engine oil, and accelerate the oxidation and deterioration of the engine oil. Water vapor condenses in the engine oil to form sludge and block the oil circuit. Acidic gases in the exhaust gas mix into the lubrication system, causing corrosion and accelerated wear of engine parts. Blowby can also cause the crankcase pressure to be too high and destroy the crankcase seal, causing the oil to leak and lose, causing the crankcase ventilation system to malfunction, the oil to emulsify and other problems, resulting in reduced engine performance or even damage to the engine.

[0003] Therefore, it is necessary to design a monitoring method for a crankcase ventilation system that solves the above technical problems. Summary of the invention

[0004] The present application provides a monitoring method for a crankcase ventilation system and a crankcase ventilation system. While utilizing an external air source component to obtain a high-efficiency oil-gas separation efficiency, the crankcase ventilation system monitors at least one of the state of the crankcase ventilation system pipeline, the working state of the air-assisted oil-gas separator, and the emulsified state of the engine oil by obtaining the parameter value of the air-assisted oil-gas separator.

[0005] According to a first aspect of an embodiment of this specification, a method for monitoring a crankcase ventilation system is provided.

[0006] The crankcase ventilation system includes a crankcase assembly, an air-assisted oil-gas separator, a supercharger assembly, an intake manifold and an external air source assembly, wherein the crankcase assembly, the air-assisted oil-gas separator, the supercharger assembly and the intake manifold form a circuit, the external air source assembly is connected to the air-assisted oil-gas separator and provides a stable air source, and the state of the crankcase ventilation system is monitored by monitoring the parameter value of the air-assisted oil-gas separator, including: monitoring the state of the crankcase ventilation system pipeline, wherein the parameter value includes the pressure value and the difference between the pressure at the oil-gas inlet and the air outlet of the air-assisted oil-gas separator; and / or

[0007] Monitoring the working state of the air-assisted oil-gas separator, wherein the parameter value includes the temperature value and the difference between the temperature value at the air inlet and the air outlet of the air-assisted oil-gas separator; and / or

[0008] The emulsification state of the engine oil is monitored, and the parameter value includes the temperature value of the oil and gas inlet of the air-assisted oil-gas separator.

[0009] Furthermore, the monitoring of the status of the crankcase ventilation system pipeline specifically includes the following methods:

[0010] Determine a first target pressure drop and a second target pressure drop corresponding to the oil and gas inlet and the gas outlet of the air-assisted oil and gas separator under different working conditions of the methanol engine, wherein the first target pressure drop is less than the second target pressure drop;

[0011] When the methanol engine is working, the pressure value at the oil and gas inlet and the pressure value at the gas outlet of the air-assisted oil and gas separator are obtained, and the actual pressure drop at the oil and gas inlet and the gas outlet of the air-assisted oil and gas separator is obtained;

[0012] comparing the actual pressure drop with the first target pressure drop and the second target pressure drop,

[0013] The pipeline status of the crankcase ventilation system is diagnosed according to the comparison result.

[0014] Further, diagnosing the pipeline status of the crankcase ventilation system according to the comparison result specifically includes:

[0015] When the actual pressure drop is less than or equal to the first target pressure drop, the crankcase ventilation system pressure is normal, and the diagnosis result is that the pipeline state is normal;

[0016] When the actual pressure drop is greater than the first target pressure drop and less than or equal to the second target pressure drop, the crankcase ventilation system pressure is abnormal, and the diagnosis result is that the pipeline is loose;

[0017] When the actual pressure drop is greater than the second target pressure drop, the crankcase ventilation system pressure is abnormal, and the diagnosis result is that the pipeline is disconnected.

[0018] Further, determining the first target pressure drop and the second target pressure drop corresponding to the oil and gas inlet and the gas outlet of the air-assisted oil and gas separator under different working conditions of the methanol engine specifically includes:

[0019] By measuring the pressure in the crankcase assembly and the pressure at the air outlet of the air-assisted oil-gas separator under multiple operating conditions of the methanol engine on a test bench, a plurality of pressure drops in the crankcase assembly and at the air outlet of the air-assisted oil-gas separator corresponding to the multiple operating conditions are obtained, wherein the plurality of pressure drops are obtained under two conditions: a normal pipeline and a loose pipeline;

[0020] Selecting a maximum value from a plurality of pressure drops obtained when the pipeline is in a normal state as a first target pressure drop;

[0021] A maximum value among a plurality of pressure drops obtained when the pipeline is in a loose state is selected as the second target pressure drop.

[0022] Furthermore, the pressure value at the oil and gas inlet of the air-assisted oil and gas separator is obtained by measuring the pressure in the crankcase assembly.

[0023] Furthermore, the monitoring of the working state of the air-assisted oil-gas separator specifically includes the following methods:

[0024] Determine a first target temperature drop and a second target temperature drop corresponding to the air inlet and the air outlet of the air-assisted oil-gas separator at the stable air source under different working conditions of the methanol engine, wherein the first target temperature drop is less than the second target temperature drop;

[0025] When the methanol engine is working, the temperature value at the air inlet of the stable air source of the air-assisted oil-gas separator and the temperature value at the air outlet of the air-assisted oil-gas separator are obtained, and the actual temperature drop at the oil-gas inlet and the air outlet of the air-assisted oil-gas separator is obtained;

[0026] Compare the actual temperature drop with the first target temperature drop and the second target temperature drop,

[0027] The working state of the air-assisted oil-gas separator is diagnosed according to the comparison result.

[0028] Further, the working state of the air-assisted oil-gas separator is diagnosed according to the comparison result, specifically including:

[0029] When the actual temperature drop is less than or equal to the first target temperature drop, the temperature of the air-assisted oil-gas separator is normal, and the diagnosis result is normal;

[0030] When the actual temperature drop is greater than the first target temperature drop and less than or equal to the second target temperature drop, the temperature of the air-assisted oil-gas separator is abnormal, and the diagnosis result is blockage;

[0031] When the actual temperature drop is greater than or equal to the second target temperature drop, the temperature of the air-assisted oil-gas separator is abnormal, and the diagnosis result is stuck.

[0032] Further, determining the first target temperature drop and the second target temperature drop corresponding to the air inlet and the air outlet of the air-assisted oil-gas separator at the stable air source under different working conditions of the methanol engine specifically includes:

[0033] By measuring the temperature of the stable air source inlet of the air-assisted oil-gas separator and the temperature at the air outlet of the air-assisted oil-gas separator under multiple operating conditions of the methanol engine on a test bench, multiple temperature drops at the stable air source inlet of the air-assisted oil-gas separator and the air outlet of the air-assisted oil-gas separator are obtained; the multiple temperature drops are obtained respectively when the air-assisted oil-gas separator is in a normal state and a blocked state;

[0034] Selecting a maximum value from a plurality of temperature drops obtained in a normal state of the air-assisted oil-gas separator as a first target temperature drop;

[0035] A maximum value among a plurality of temperature drops obtained when the air-assisted oil-gas separator is in a blocked state is selected as the second target temperature drop.

[0036] Furthermore, the monitoring of the emulsification state of the engine oil specifically includes the following method:

[0037] Determine the target temperature value of the oil and gas inlet of the air-assisted oil and gas separator under different working conditions of the methanol engine;

[0038] When the methanol engine is working, the temperature at the oil and gas inlet of the air-assisted oil and gas separator is obtained, and the actual temperature value of the oil and gas inlet of the air-assisted oil and gas separator under steady-state conditions is obtained;

[0039] Comparing the actual temperature value with the target temperature value,

[0040] Diagnose the oil emulsification status based on the comparison results:

[0041] When the actual temperature value is less than or equal to the target temperature value, the diagnosis result is normal;

[0042] When the actual temperature value is greater than the target temperature value, the diagnosis result is oil emulsification.

[0043] Further, determining the target temperature value of the oil and gas inlet of the air-assisted oil and gas separator under different working conditions of the methanol engine specifically includes:

[0044] By measuring the inlet temperature of the gas-assisted oil-gas separator of the methanol engine under different working conditions, different water temperatures, different speeds and different loads on the test bench, a plurality of temperature values ​​are obtained;

[0045] The maximum value among the obtained multiple temperature values ​​is selected as the target temperature value.

[0046] Further, the crankcase ventilation system controls the minimum air supply delivered by the external air source assembly to the air-assisted oil-gas separator according to the actual pressure value at the air outlet of the air-assisted oil-gas separator, including:

[0047] Determine a plurality of corresponding target pressure values ​​at the gas outlet of the air-assisted oil-gas separator under a plurality of operating conditions of the methanol engine;

[0048] When the methanol engine is working, measuring the actual pressure value at the air outlet of the air-assisted oil-gas separator;

[0049] Obtaining the operating condition of the methanol engine during measurement and the target pressure value corresponding to the operating condition;

[0050] comparing the actual pressure value with the obtained target pressure value;

[0051] The minimum air supply amount is controlled according to the comparison result.

[0052] Furthermore, the determination of the multiple target pressure values ​​corresponding to the gas outlet of the air-assisted oil-gas separator under multiple operating conditions of the methanol engine is obtained by the following method:

[0053] Measuring multiple pressure values ​​corresponding to the gas outlet of the air-assisted oil-gas separator under multiple operating conditions of the methanol engine on an engine bench;

[0054] The multiple pressure values ​​obtained by measurement are used as target pressure values ​​of the air outlet of the air-assisted oil-gas separator under multiple operating conditions of the methanol engine.

[0055] Furthermore, the external gas source component includes an electrically controlled proportional valve, and the minimum gas supply volume delivered by the external gas source component to the air-assisted oil-gas separator is controlled by adjusting the duty cycle of the electrically controlled proportional valve; the operating conditions of the methanol engine include the engine operating state, speed and load.

[0056] According to a second aspect of an embodiment of the present specification, a crankcase ventilation system is provided, comprising a crankcase assembly, an air-assisted oil-gas separator, a supercharger assembly, an intake manifold, an external air source assembly, a measuring assembly and a control unit, wherein the crankcase assembly, the air-assisted oil-gas separator, the supercharger assembly and the intake manifold are connected in sequence; the external air source assembly is connected to the air-assisted oil-gas separator, the external air source assembly comprises an external air source and an electrically controlled proportional valve, and the electrically controlled proportional valve is arranged between the external air source and the air-assisted oil-gas separator; the control unit is electrically connected to the external air source assembly and the measuring assembly; the measuring assembly comprises a pressure sensor and / or a temperature sensor.

[0057] Furthermore, the pressure sensor includes a front pressure sensor and a rear pressure sensor, and the front pressure sensor and the rear pressure sensor are used to measure the pressure at the oil and gas inlet and the gas outlet of the air-assisted oil-gas separator.

[0058] Furthermore, the temperature sensor also includes an air source temperature sensor and a rear temperature sensor. The air source temperature sensor is used to measure the temperature of the stable air source inlet of the air-assisted oil-gas separator, and the rear temperature sensor is used to measure the temperature at the air outlet of the air-assisted oil-gas separator.

[0059] Furthermore, the temperature sensor also includes a front temperature sensor, and the front temperature sensor is used to measure the temperature of the oil and gas inlet of the air-assisted oil and gas separator.

[0060] The present application has the following beneficial effects: while the crankcase ventilation system utilizes an external air source component to obtain high oil-gas separation efficiency, it monitors the state of the crankcase ventilation system pipeline, the working state of the air-assisted oil-gas separator and the emulsification state of the engine oil by obtaining the parameter value of the air-assisted oil-gas separator.

[0061] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the specification and, together with the description, serve to explain the principles of the specification.

[0063] Figure 1 is a schematic diagram of the crankcase ventilation system of the present application;

[0064] Figure 2 is a schematic diagram of the measurement components of this application;

[0065] Figure 3 is a flow chart of the present application for monitoring the status of the crankcase ventilation system pipeline;

[0066] Figure 4 is a schematic diagram of the present application for diagnosing the status of the crankcase ventilation system piping;

[0067] Figure 5 is a flow chart of obtaining the first target pressure drop and the second target pressure drop in the present application;

[0068] Figure 6 It is a flow chart of the present application for monitoring the working status of the air-assisted oil-gas separator;

[0069] Figure 7 It is a schematic diagram of the present application for diagnosing the working status of the air-assisted oil-gas separator;

[0070] Figure 8 is a flow chart of obtaining the first target temperature drop and the second target temperature drop in this application;

[0071] Fig. 9 is a flow chart of the present application for monitoring the emulsification state of engine oil;

[0072] Fig.10 is a schematic diagram of the present application for diagnosing the emulsified state of engine oil;

[0073] Fig.11 It is a flow chart of obtaining the target temperature value of this application;

[0074] Fig.12 This is a flow chart of regulating the driving gas volume in this application;

[0075] Fig.13 It is a schematic diagram of adjusting the driving gas volume in this application.

[0076] Description of reference numerals:

[0077] 10-crankcase assembly; 20-air-assisted oil-gas separator; 21-oil and gas inlet; 22-air outlet; 23-air inlet; 30-supercharger assembly; 31-supercharger; 32-intercooler; 40-intake manifold; 50-external air source assembly; 51-electrically controlled proportional valve; 52-external air source; 60-measuring assembly; 61-front pressure sensor; 62-rear pressure sensor; 63-air source temperature sensor; 64-rear temperature sensor; 65-front temperature sensor; 70-control unit. DETAILED DESCRIPTION

[0078] Here, the technical solutions in the embodiments (or "implementation methods") of the present application will be described clearly and completely in conjunction with the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements.

[0079] If there are terms involving directional indications or positional relationships in the embodiments of the present application (such as up, down, left, right, front, back, inside, outside, top, bottom, center, vertical, horizontal, longitudinal, transverse, length, width, counterclockwise, clockwise, axial, radial, circumferential, etc.), such terms are only used to explain the relative positional relationship, movement, etc. between the components under a certain specific posture (as shown in the accompanying drawings); if the specific posture changes, the directional indication or positional relationship will also change accordingly. In addition, the terms "first" and "second" in the embodiments of the present application are only used for the purpose of convenience of description and cannot be understood as indicating or implying relative importance.

[0080] Next, the embodiments of this specification are described in detail.

[0081] This embodiment discloses a monitoring method for a crankcase ventilation system, which is applied to a crankcase ventilation system of a methanol engine.

[0082] Reference Figure 1 and Figure 2As shown, the crankcase ventilation system includes a crankcase assembly 10, an air-assisted oil-gas separator 20, a supercharger assembly 30, an intake manifold 40, an external air source assembly 50, a measuring assembly 60 and a control unit 70. The crankcase assembly 10, the air-assisted oil-gas separator 20, the supercharger assembly 30 and the intake manifold 40 are sequentially connected to form a loop. A large amount of water vapor and a small amount of unburned methanol vapor are re-combusted and utilized again through the loop in the crankcase ventilation system.

[0083] The external air source assembly 50 is in communication with the air-assisted oil-gas separator 20, and provides a continuous and stable air source for the air-assisted oil-gas separator 20, so as to improve the separation efficiency of the air-assisted oil-gas separator 20. Specifically, the external air source assembly 50 includes an electric-controlled proportional valve 51 and an external air source 52, and the electric-controlled proportional valve 51 is arranged between the external air source 52 and the air-assisted oil-gas separator 20. The control unit 70 is electrically connected to the electric-controlled proportional valve 51 of the external air source assembly 50, and the control unit 70 controls the input amount of the external air source 52 by adjusting the opening of the electric-controlled proportional valve 51. The control unit 70 is also electrically connected to the measuring assembly 60, and obtains the parameter value of the measuring assembly 60, and then monitors the state of the crankcase ventilation system through the parameter value.

[0084] The measuring assembly 60 includes a pressure sensor and a temperature sensor. The pressure sensor includes a front pressure sensor 61 and a rear pressure sensor 62. The temperature sensor includes an air source temperature sensor 63, a rear temperature sensor 64, and a front temperature sensor 65. The front pressure sensor 61 is used to measure the pressure at the oil and gas inlet 21 of the air-assisted oil-gas separator 20, the rear pressure sensor 62 is used to measure the pressure at the air outlet 22 of the air-assisted oil-gas separator 20, the air source temperature sensor 63 is used to measure the temperature of the air source input to the external air source assembly 50, the rear temperature sensor 64 is used to measure the temperature at the air outlet 22 of the air-assisted oil-gas separator 20, and the front temperature sensor 65 is used to measure the temperature at the oil and gas inlet 21 of the air-assisted oil-gas separator 20.

[0085] The state of the crankcase ventilation system includes the state of the crankcase ventilation system pipeline, the working state of the air-assisted oil-gas separator and the emulsified state of the engine oil. The state of the crankcase ventilation system is monitored by obtaining different parameter values ​​in the above-mentioned measuring component 60.

[0086] When monitoring the status of the crankcase ventilation system pipeline, the parameter values ​​measured by the front pressure sensor 61 and the rear pressure sensor 62 include the pressure values ​​at the oil and gas inlet 21 and the outlet 22 of the air-assisted oil and gas separator 20, and the difference is obtained from the above two pressure values.

[0087] When monitoring the working status of the air-assisted oil-gas separator, the parameter values ​​measured by the air source temperature sensor 63 and the rear temperature sensor 64 include the temperature values ​​at the stable air source inlet 23 and the air outlet 22 of the air-assisted oil-gas separator 20, and the difference is obtained from the above two temperature values.

[0088] When monitoring the emulsified state of the engine oil, the parameter value measured by the front temperature sensor 65 includes the temperature value of the oil-gas inlet 21 of the air-assisted oil-gas separator 20 .

[0089] Reference Figure 3 , Figure 4 and Figure 5 As shown, monitoring the status of the crankcase ventilation system pipeline specifically includes the following methods:

[0090] S101: Determine a first target pressure drop and a second target pressure drop corresponding to the oil and gas inlet 21 and the gas outlet 22 of the air-assisted oil-gas separator 20 under different working conditions of the methanol engine, wherein the first target pressure drop is smaller than the second target pressure drop.

[0091] S102: When the methanol engine is working, the pressure value at the oil and gas inlet 21 of the air-assisted oil and gas separator 20 and the pressure value at the air outlet 22 of the air-assisted oil and gas separator 20 are obtained, and the actual pressure drop at the oil and gas inlet 21 and the air outlet 22 of the air-assisted oil and gas separator 20 is obtained.

[0092] The actual pressure drop is the difference between the pressure value at the oil-gas inlet 21 of the air-assisted oil-gas separator 20 and the pressure value at the air outlet 22 of the air-assisted oil-gas separator 20, and the difference here is greater than zero. In this embodiment, the pressure value at the air outlet 22 of the air-assisted oil-gas separator 20 is measured by the rear pressure sensor 62 arranged on the connecting pipeline between the air-assisted oil-gas separator 20 and the supercharger assembly 30, and the pressure value at the oil-gas inlet 21 of the air-assisted oil-gas separator 20 is measured by the front pressure sensor 61 arranged on the crankcase assembly 10.

[0093] S103: Compare the actual pressure drop with the first target pressure drop and the second target pressure drop.

[0094] S104: Diagnose the pipeline status of the crankcase ventilation system according to the comparison result.

[0095] The diagnosis method of pipeline status is:

[0096] When the actual pressure drop is less than or equal to the first target pressure drop, the crankcase ventilation system pressure is normal, and the diagnosis result is that the pipeline status is normal.

[0097] When the actual pressure drop is greater than the first target pressure drop and less than or equal to the second target pressure drop, the crankcase ventilation system pressure is abnormal, and the diagnosis result is that the pipeline is loose.

[0098] When the actual pressure drop is greater than the second target pressure drop, the crankcase ventilation system pressure is abnormal, and the diagnosis result is that the pipeline is disconnected.

[0099] It should be noted that the crankcase assembly 10 and the air-assisted oil-gas separator 20 correspond to multiple different working conditions under different working conditions at the outlet 22. The above diagnostic method can be used to warn in advance whether the pipes in the crankcase ventilation system are abnormal and whether the crankcase ventilation system has achieved a closed loop.

[0100] The first target pressure drop and the second target pressure drop corresponding to the oil and gas inlet 21 and the gas outlet 22 of the air-assisted oil and gas separator 20 under different working conditions of the methanol engine are determined by the following method:

[0101] S201: By measuring the pressure inside the crankcase assembly 10 and the pressure at the air outlet 22 of the air-assisted oil-gas separator 20 of the methanol engine under multiple operating conditions on the test bench, multiple pressure drops inside the crankcase assembly 10 and at the air outlet 22 of the air-assisted oil-gas separator 20 corresponding to the multiple operating conditions are obtained. The multiple pressure drops are obtained under two conditions: normal pipeline state and loose pipeline state.

[0102] S202: Selecting a maximum value from a plurality of pressure drops obtained when the pipeline is in a normal state as a first target pressure drop.

[0103] S203: Selecting a maximum value from a plurality of pressure drops obtained when the pipeline is in a loose state as a second target pressure drop.

[0104] Reference Figure 6 , Figure 7 and Figure 8 As shown, monitoring the working state of the air-assisted oil-gas separator 20 specifically includes the following methods:

[0105] S301: Determine the first target temperature drop and the second target temperature drop corresponding to the stable air source inlet 23 and the air outlet 22 of the air-assisted oil-gas separator 20 under different working conditions of the methanol engine, wherein the first target temperature drop is smaller than the second target temperature drop.

[0106] S302: When the methanol engine is working, the temperature value at the stable air source inlet 23 of the air-assisted oil-gas separator 20 and the temperature value at the air outlet 22 of the air-assisted oil-gas separator 20 are obtained, and the actual temperature drop at the stable air source inlet 23 and the air outlet 22 of the air-assisted oil-gas separator 20 is obtained.

[0107] The actual temperature drop is the difference between the temperature value at the stable air source inlet 23 of the air-assisted oil-gas separator 20 and the temperature value at the air outlet 22 of the air-assisted oil-gas separator 20, and the difference here is greater than zero. The temperature value at the stable air source inlet 23 of the air-assisted oil-gas separator 20 is measured by the air source temperature sensor 63 arranged on the connecting pipeline between the external air source assembly 50 and the air-assisted oil-gas separator 20, and the temperature value at the air outlet 22 of the air-assisted oil-gas separator 20 is measured by the rear temperature sensor 64 arranged on the connecting pipeline between the air-assisted oil-gas separator 20 and the supercharger assembly 30. In this embodiment, the rear temperature sensor 64 and the rear pressure sensor 62 are integrated together.

[0108] S303: Compare the actual temperature drop with the first target temperature drop and the second target temperature drop.

[0109] S304: Diagnose the working state of the air-assisted oil-gas separator 20 according to the comparison result.

[0110] Diagnosing the working state of the air-assisted oil-gas separator 20 according to the comparison result specifically includes:

[0111] When the actual temperature drop is less than or equal to the first target temperature drop, the temperature of the air-assisted oil-gas separator 20 is normal, and the diagnosis result is normal.

[0112] When the actual temperature drop is greater than the first target temperature drop and less than or equal to the second target temperature drop, the temperature of the air-assisted oil-gas separator 20 is abnormal, and the diagnosis result is blockage.

[0113] When the actual temperature drop is greater than the second target temperature drop, the temperature of the air-assisted oil-gas separator 20 is abnormal, and the diagnosis result is stuck.

[0114] Determining the first target temperature drop and the second target temperature drop corresponding to the stable air source air inlet 23 and the air outlet 22 of the air-assisted oil-gas separator 20 under different working conditions of the methanol engine specifically includes:

[0115] S401: By measuring the temperature of the stable air source inlet 23 of the air-assisted oil-gas separator 20 and the temperature at the air outlet 22 of the air-assisted oil-gas separator 20 of the methanol engine under multiple operating conditions on the test bench, multiple temperature drops at the stable air source inlet 23 of the air-assisted oil-gas separator 20 and the air outlet 22 of the air-assisted oil-gas separator 20 corresponding to the multiple operating conditions are obtained. The multiple temperature drops are obtained when the air-assisted oil-gas separator 20 is in normal and blocked states respectively.

[0116] S402: Selecting a maximum value from a plurality of temperature drops obtained in a normal state of the air-assisted oil-gas separator 20 as a first target temperature drop.

[0117] S403: Selecting a maximum value from a plurality of temperature drops obtained when the air-assisted oil-gas separator 20 is in a blocked state as a second target temperature drop.

[0118] Reference Fig. 9 , Fig.10 and Fig.11 As shown, monitoring the emulsification state of engine oil specifically includes the following methods:

[0119] S501: Determine the target temperature value of the oil and gas inlet 21 of the air-assisted oil and gas separator 20 under different working conditions of the methanol engine.

[0120] S502: When the methanol engine is working, the temperature at the oil and gas inlet 21 of the air-assisted oil and gas separator 20 is measured to obtain the actual temperature value of the oil and gas inlet 21 of the air-assisted oil and gas separator 20 under steady-state conditions.

[0121] The front temperature sensor 65 is used to measure the temperature of the oil-gas inlet 21 of the air-assisted oil-gas separator 20. The front temperature sensor 65 can be arranged on a pipeline connecting the crankcase assembly 10 and the oil-gas inlet 21 of the air-assisted oil-gas separator 20.

[0122] S503: Compare the actual temperature value with the target temperature value.

[0123] S504: Diagnose the emulsification state of the engine oil according to the comparison result.

[0124] Specifically, when the actual temperature value is less than or equal to the target temperature value, the diagnosis result is normal. When the actual temperature value is greater than the target temperature value, the diagnosis result is oil emulsification.

[0125] The target temperature value of the oil and gas inlet 21 of the air-assisted oil and gas separator 20 is determined under different working conditions of the methanol engine, and is obtained by the following method:

[0126] S601: On a test bench, a plurality of temperature values ​​are obtained by measuring the inlet temperature of the air-assisted oil-gas separator 20 of the methanol engine under different working conditions, different water temperatures, different speeds and different loads under the premise of selecting the engine oil grade.

[0127] S602: Selecting a maximum value from the obtained multiple temperature values ​​as a target temperature value.

[0128] Through sufficient testing on the bench, the effects of various oil qualities and air-assisted oil-gas separators 20 in different working states on the crankcase ventilation system can be identified, thereby improving the accuracy of the model. In addition, the end user can accurately identify the current state of the air-assisted oil-gas separator 20 during actual use.

[0129] It should be noted that when there is a problem with the pipeline, the air-assisted oil-gas separator 20 or the engine oil, it will be fed back to the control unit 70, and then fed back to the terminal through the control unit 70. The above three situations are independent of each other. When one or more of the above situations occur, the terminal will issue an early warning respectively.

[0130] Reference Fig.12 and Fig.13 As shown, the method of adjusting the driving gas volume includes:

[0131] S701: Determine multiple target pressure values ​​corresponding to the outlet of the air-assisted oil-gas separator 20 under multiple operating conditions of the methanol engine.

[0132] The method for determining the target pressure value includes: measuring a plurality of pressure values ​​corresponding to the outlet of the air-assisted oil-gas separator 20 of the methanol engine under a plurality of operating conditions at the initial stage of the engine bench calibration, and using the measured plurality of pressure values ​​as the target pressure values ​​of the outlet of the air-assisted oil-gas separator 20 of the methanol engine under a plurality of operating conditions. Each operating condition corresponds to a target pressure value.

[0133] S702: When the methanol engine is operating, measure the actual pressure value at the outlet of the air-assisted oil-gas separator 20.

[0134] In the present application, the front pressure sensor 61 is arranged on the crankcase assembly 10 , and the rear pressure sensor 62 is arranged on the connecting pipeline between the air-assisted oil-gas separator 20 and the supercharger assembly 30 .

[0135] S703: Obtain the operating condition of the methanol engine during measurement and the target pressure value corresponding to the operating condition.

[0136] The above-mentioned different operating conditions are related to the operating state, speed and operating load of the methanol engine.

[0137] S704: Compare the actual pressure value with the obtained target pressure value.

[0138] S705: Controlling the minimum air supply volume delivered by the external air source assembly 50 to the air-assisted oil-gas separator 20 according to the comparison result.

[0139] Specifically, the actual pressure values ​​measured after the methanol engine is started are compared to obtain the difference between the two pressure values. The minimum air supply required to be delivered by the external air source to the air-assisted oil-gas separator 20 is determined according to the difference, and the minimum air supply is achieved by adjusting the duty cycle of the electronically controlled proportional valve 51.

[0140] The crankcase ventilation system of the present application uses an external air source component to obtain high oil-gas separation efficiency. By monitoring the parameter values ​​of the air-assisted oil-gas separator 20, and combining the target values ​​of the oil with different degrees of degradation and the air-assisted oil-gas separator 20 in different aging states obtained by the previous bench calibration, the parameter values ​​are compared and analyzed with the target values ​​of the bench calibration, and the current state of the crankcase ventilation system can be accurately monitored. Users can use this to warn whether the current vehicle has a crankcase ventilation system failure, thereby avoiding the risk of hardware damage in advance.

[0141] It should be noted that the technical solutions or technical features described in the above embodiments can be combined or supplemented with each other without causing conflicts. The scope of protection of this application is not limited to the precise structures described in the above embodiments and shown in the drawings; all modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of this application should be included in the scope of protection of this application.

Claims

1. A method for monitoring a crankcase ventilation system, characterized in that: The crankcase ventilation system includes a crankcase assembly, an air-assisted oil-gas separator, a supercharger assembly, an intake manifold and an external air source assembly. The crankcase assembly, the air-assisted oil-gas separator, the supercharger assembly and the intake manifold form a loop. The external air source assembly is connected to the air-assisted oil-gas separator and provides a stable air source. The state of the crankcase ventilation system is monitored by obtaining a parameter value of the air-assisted oil-gas separator, including: Monitoring the status of the crankcase ventilation system pipeline, the parameter value includes the pressure value and the difference between the oil and gas inlet and the gas outlet of the air-assisted oil and gas separator; The method of monitoring the status of the crankcase ventilation system pipeline specifically includes the following methods: Determine a first target pressure drop and a second target pressure drop corresponding to the oil and gas inlet and the gas outlet of the air-assisted oil and gas separator under different working conditions of the methanol engine, wherein the first target pressure drop is less than the second target pressure drop; When the methanol engine is working, the pressure value at the oil and gas inlet and the pressure value at the gas outlet of the air-assisted oil and gas separator are obtained, and the actual pressure drop at the oil and gas inlet and the gas outlet of the air-assisted oil and gas separator is obtained; comparing the actual pressure drop with the first target pressure drop and the second target pressure drop; The pipeline status of the crankcase ventilation system is diagnosed according to the comparison result.

2. The method for monitoring a crankcase ventilation system according to claim 1, characterized in that: Diagnosing the pipeline status of the crankcase ventilation system according to the comparison result specifically includes: When the actual pressure drop is less than or equal to the first target pressure drop, the crankcase ventilation system pressure is normal, and the diagnosis result is that the pipeline state is normal; When the actual pressure drop is greater than the first target pressure drop and less than or equal to the second target pressure drop, the crankcase ventilation system pressure is abnormal, and the diagnosis result is that the pipeline is loose; When the actual pressure drop is greater than the second target pressure drop, the crankcase ventilation system pressure is abnormal, and the diagnosis result is that the pipeline is disconnected.

3. The method for monitoring a crankcase ventilation system according to claim 1, characterized in that: Determining the first target pressure drop and the second target pressure drop corresponding to the oil and gas inlet and the gas outlet of the air-assisted oil and gas separator under different working conditions of the methanol engine specifically includes: By measuring the pressure in the crankcase assembly and the pressure at the air outlet of the air-assisted oil-gas separator under multiple operating conditions of the methanol engine on a test bench, multiple pressure drops in the crankcase assembly and at the air outlet of the air-assisted oil-gas separator are obtained, and the multiple pressure drops are obtained under two conditions: a normal pipeline and a loose pipeline; Selecting a maximum value from a plurality of pressure drops obtained when the pipeline is in a normal state as a first target pressure drop; A maximum value among a plurality of pressure drops obtained when the pipeline is in a loose state is selected as the second target pressure drop.

4. The method for monitoring a crankcase ventilation system according to claim 1, characterized in that: The pressure value at the oil and gas inlet of the air-assisted oil and gas separator is obtained by measuring the pressure in the crankcase assembly.

5. A method for monitoring a crankcase ventilation system, characterized in that: The crankcase ventilation system includes a crankcase assembly, an air-assisted oil-gas separator, a supercharger assembly, an intake manifold and an external air source assembly. The crankcase assembly, the air-assisted oil-gas separator, the supercharger assembly and the intake manifold form a loop. The external air source assembly is connected to the air-assisted oil-gas separator and provides a stable air source. The state of the crankcase ventilation system is monitored by obtaining a parameter value of the air-assisted oil-gas separator, including: Monitoring the working state of the air-assisted oil-gas separator, wherein the parameter value includes the temperature value and the difference between the temperature value at the air inlet and the air outlet of the air-assisted oil-gas separator; The method of monitoring the working state of the air-assisted oil-gas separator specifically includes the following steps: Determine a first target temperature drop and a second target temperature drop corresponding to the air inlet and the air outlet of the air-assisted oil-gas separator at the stable air source under different working conditions of the methanol engine, wherein the first target temperature drop is less than the second target temperature drop; When the methanol engine is working, the temperature value at the air inlet of the stable air source of the air-assisted oil-gas separator and the temperature value at the air outlet of the air-assisted oil-gas separator are obtained, and the actual temperature drop at the oil-gas inlet and the air outlet of the air-assisted oil-gas separator is obtained; Comparing the actual temperature drop with the first target temperature drop and the second target temperature drop; The working state of the air-assisted oil-gas separator is diagnosed according to the comparison result.

6. The method for monitoring a crankcase ventilation system according to claim 5, characterized in that: Diagnosing the working state of the air-assisted oil-gas separator according to the comparison result specifically includes: When the actual temperature drop is less than or equal to the first target temperature drop, the temperature of the air-assisted oil-gas separator is normal, and the diagnosis result is normal; When the actual temperature drop is greater than the first target temperature drop and less than or equal to the second target temperature drop, the temperature of the air-assisted oil-gas separator is abnormal, and the diagnosis result is blockage; When the actual temperature drop is greater than or equal to the second target temperature drop, the temperature of the air-assisted oil-gas separator is abnormal, and the diagnosis result is stuck.

7. The method for monitoring a crankcase ventilation system according to claim 5, characterized in that: Determining the first target temperature drop and the second target temperature drop corresponding to the air inlet and the air outlet of the air-assisted oil-gas separator at the stable air source under different working conditions of the methanol engine specifically includes: By measuring the temperature of the stable air source inlet of the air-assisted oil-gas separator and the temperature at the air outlet of the air-assisted oil-gas separator under multiple operating conditions of the methanol engine on a test bench, multiple temperature drops at the stable air source inlet of the air-assisted oil-gas separator and the air outlet of the air-assisted oil-gas separator are obtained; the multiple temperature drops are obtained respectively when the air-assisted oil-gas separator is in a normal state and a blocked state; Selecting a maximum value from a plurality of temperature drops obtained in a normal state of the air-assisted oil-gas separator as a first target temperature drop; A maximum value among a plurality of temperature drops obtained when the air-assisted oil-gas separator is in a blocked state is selected as the second target temperature drop.

8. The method for monitoring a crankcase ventilation system according to claim 1 or 5, characterized in that: The crankcase ventilation system controls the minimum air supply delivered by the external air source component to the air-assisted oil-gas separator according to the actual pressure value at the air outlet of the air-assisted oil-gas separator, including: Determine a plurality of corresponding target pressure values ​​at the gas outlet of the air-assisted oil-gas separator under a plurality of operating conditions of the methanol engine; When the methanol engine is working, measuring the actual pressure value at the air outlet of the air-assisted oil-gas separator; Obtaining the operating condition of the methanol engine during measurement and the target pressure value corresponding to the operating condition; comparing the actual pressure value with the obtained target pressure value; The minimum air supply amount is controlled according to the comparison result.

9. The method for monitoring a crankcase ventilation system according to claim 8, characterized in that: The determination of the multiple target pressure values ​​corresponding to the gas outlet of the air-assisted oil-gas separator under multiple operating conditions of the methanol engine is obtained by the following method: Measuring multiple pressure values ​​corresponding to the gas outlet of the air-assisted oil-gas separator under multiple operating conditions of the methanol engine on an engine bench; The multiple pressure values ​​obtained by measurement are used as target pressure values ​​of the air outlet of the air-assisted oil-gas separator under multiple operating conditions of the methanol engine.

10. The method for monitoring a crankcase ventilation system according to claim 8, characterized in that: The external gas source component includes an electrically controlled proportional valve, and the minimum gas supply volume delivered by the external gas source component to the air-assisted oil-gas separator is controlled by adjusting the duty cycle of the electrically controlled proportional valve; the operating conditions of the methanol engine include the engine operating state, speed and load.

11. A crankcase ventilation system, characterized in that: A monitoring method for a crankcase ventilation system as described in claim 1 or 5, wherein the crankcase ventilation system includes a crankcase assembly, an air-assisted oil-gas separator, a supercharger assembly, an intake manifold, an external air source assembly, a measuring assembly and a control unit, wherein the crankcase assembly, the air-assisted oil-gas separator, the supercharger assembly and the intake manifold are connected in sequence; the external air source assembly is connected to the air-assisted oil-gas separator, and the external air source assembly includes an external air source and an electrically controlled proportional valve, and the electrically controlled proportional valve is arranged between the external air source and the air-assisted oil-gas separator; the control unit is electrically connected to the external air source assembly and the measuring assembly; the measuring assembly is used to measure the temperature or pressure of the air-assisted oil-gas separator to monitor the state of the crankcase ventilation system, and the measuring assembly includes a pressure sensor and / or a temperature sensor.

12. The crankcase ventilation system according to claim 11, characterized in that The pressure sensor comprises a front pressure sensor and a rear pressure sensor, and the front pressure sensor and the rear pressure sensor are used to measure the pressure at the oil and gas inlet and the gas outlet of the air-assisted oil and gas separator.

13. The crankcase ventilation system of claim 11, wherein: The temperature sensor also includes an air source temperature sensor and a rear temperature sensor. The air source temperature sensor is used to measure the temperature of the stable air source inlet of the air-assisted oil-gas separator, and the rear temperature sensor is used to measure the temperature at the air outlet of the air-assisted oil-gas separator.

14. The crankcase ventilation system of claim 11, wherein: The temperature sensor further comprises a front temperature sensor, and the front temperature sensor is used to measure the temperature of the oil and gas inlet of the air-assisted oil and gas separator.

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