A method for determining a structure of a crankcase blow-by hole

Abstract

This invention relates to the field of crankcase technology and discloses a method for determining the blow-by port structure of a crankcase. The method includes: obtaining the total blow-by volume of each cylinder in the crankcase; setting a preset value for the minimum cross-sectional area of ​​the blow-by channel on the wall of each target main bearing; simulating the blow-by channels on the wall of each target main bearing based on the total blow-by volume of each cylinder and the preset value of the minimum cross-sectional area of ​​each blow-by channel; determining the simulated value of the minimum cross-sectional area of ​​the blow-by channel on each target main bearing wall when the blow-by flow velocity in each blow-by channel is less than or equal to a preset flow velocity; determining the initial structure of the blow-by port on each target main bearing wall based on the simulated value of the minimum cross-sectional area of ​​the blow-by channel on each target main bearing wall; and determining the target structure of the blow-by port on the corresponding target main bearing wall based on the identification results and the initial structure of the blow-by port. The crankcase blow-by port structure determined by this method can balance the pressure between the cylinders in the crankcase while ensuring that the safety factor of the target main bearing wall meets the requirements.

Description

Technical Field

[0001] This invention relates to the field of crankcase technology, and in particular to a method for determining the structure of crankcase blow-through holes. Background Technology

[0002] The target main bearing walls of the crankcase (e.g., the main bearing wall between two adjacent cylinders and the main bearing wall at the end of the crankcase connected to the flywheel housing) are typically equipped with blow-through holes to balance the pressure between the cylinders in the crankcase and to reduce weight. However, in the prior art, the design of the crankcase blow-through holes cannot simultaneously balance the pressure between the cylinders in the crankcase and ensure that the safety factor of the target main bearing wall meets the requirements. Summary of the Invention

[0003] This invention provides a method for determining the crankcase blow-through hole structure. The crankcase blow-through hole structure determined by this method can balance the pressure between the cylinders of the crankcase while ensuring that the safety factor of the target main bearing wall meets the requirements.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] A method for determining the structure of a crankcase blow-through hole includes:

[0006] Obtain the total blow-by gas volume of each cylinder in the crankcase;

[0007] Set a preset value for the minimum cross-sectional area of ​​the blow-by channel on the main bearing wall of each target level. Based on the total blow-by volume of each cylinder and the preset value for the minimum cross-sectional area of ​​the blow-by channel on the main bearing wall of each target level, perform simulation processing on the blow-by channel of the main bearing wall of each target level. When the blow-by flow velocity in the blow-by channel of the main bearing wall of each target level is less than or equal to the preset flow velocity, determine the simulation value of the minimum cross-sectional area of ​​the blow-by channel on the main bearing wall of each target level.

[0008] The initial structure of the air leakage hole in the main bearing wall of each target grade is determined based on the simulation value of the minimum cross-sectional area of ​​the air leakage channel on the wall of each target grade. The initial structure of the air leakage hole includes the shape and position of the air leakage hole.

[0009] Based on the identification results and the initial structure of the vent hole, the target structure of the vent hole in the target main bearing wall is determined; wherein, the identification results indicate whether the safety factor of the target main bearing wall meets the preset conditions.

[0010] When determining the crankcase blow-through hole structure using the method provided by this invention, the blow-through hole structure of the crankcase is simulated based on the total blow-through volume of each cylinder and the preset value of the minimum cross-sectional area of ​​the blow-through channel on the target main bearing wall of each gear. The simulated value of the minimum cross-sectional area of ​​the blow-through channel on the target main bearing wall of each gear is determined when the blow-through flow velocity in the blow-through channel of each gear is less than or equal to the preset flow velocity. The initial structure of the blow-through hole on the target main bearing wall of each gear is determined based on the simulated value of the minimum cross-sectional area of ​​the blow-through channel on the target main bearing wall of each gear. The target structure of the blow-through hole on the corresponding target main bearing wall is determined based on the identification results and the initial structure of the blow-through hole. This method can balance the pressure between the cylinders of the crankcase and ensure that the safety factor of the target main bearing wall of each gear meets the preset conditions.

[0011] Optionally, determining the target structure of the corresponding vent hole in the target main bearing wall based on the identification result and the initial structure of the vent hole specifically includes:

[0012] When the identification result indicates that the safety factor of the corresponding target main bearing wall meets the preset conditions, the initial structure of the air leakage hole is taken as the target structure of the air leakage hole;

[0013] When the identification result indicates that the safety factor of the target main bearing wall does not meet the preset conditions, the air leakage hole structure on the target main bearing wall is reset, and the identification result of whether the safety factor of the target main bearing wall meets the preset conditions after the air leakage hole structure is reset is obtained; the target structure of the air leakage hole of the target main bearing wall is determined according to the identification result and the reset structure of the air leakage hole.

[0014] Optionally, when the identification result indicates that the safety factor of the corresponding target main bearing wall does not meet the preset conditions, the air leakage hole structure on the corresponding target main bearing wall is reset, and the identification result of whether the safety factor of the target main bearing wall meets the preset conditions after the air leakage hole structure is reset is obtained; the target structure of the air leakage hole on the target main bearing wall is determined according to the identification result and the reset structure of the air leakage hole, specifically including:

[0015] When the identification result indicates that the safety factor of the target main bearing wall does not meet the preset conditions, a flange is set at the opening of the corresponding air leakage hole, and the identification result of whether the safety factor of the target main bearing wall meets the preset conditions after the flange is set is obtained.

[0016] When the identification result after setting the flange indicates that the safety factor of the corresponding target main bearing wall meets the preset conditions, the structure of the air leakage hole after setting the flange is taken as the target structure of the air leakage hole.

[0017] If the identification result after setting the flange indicates that the safety factor of the target main bearing wall does not meet the preset conditions, then the shape and / or position of the vent hole is reset, and the identification result of whether the safety factor of the target main bearing wall meets the preset conditions after resetting the vent hole structure is obtained again, until the identification result indicates that the safety factor of the target main bearing wall meets the preset conditions.

[0018] Optionally, the safety factor of the target main bearing wall in each grade includes both static strength and fatigue strength safety factors. When the static strength of the target main bearing wall is greater than or equal to the preset static strength value, and the fatigue strength safety factor of the target main bearing wall is greater than or equal to the preset fatigue strength safety factor value, the identification result indicates that the safety factor of the corresponding target main bearing wall meets the preset condition.

[0019] When the static strength of the target main bearing wall is less than the preset static strength value, and / or the fatigue strength safety factor of the target main bearing wall is less than the preset fatigue strength safety factor value, the identification result indicates that the safety factor of the corresponding target main bearing wall does not meet the preset condition.

[0020] Optionally, the total blow-by gas volume includes the leakage between the piston and piston rings in the corresponding cylinder block.

[0021] Optionally, the total amount of blow-by gas also includes at least one of the following: turbocharger leakage, air compressor leakage, and valve guide leakage.

[0022] Optionally, the preset value for the minimum cross-sectional area of ​​the blow-by passage on the wall of the target main bearing for each gear is determined by simulating the blow-by passage on the wall of the target main bearing for each gear based on the total blow-by volume of each cylinder and the preset value for the minimum cross-sectional area of ​​the blow-by passage on the wall of the target main bearing for each gear. Specifically, this includes:

[0023] The three-dimensional simulation model of the respiratory system is obtained when the minimum cross-sectional area of ​​the air leakage channel on the wall of the target main bearing for each grade is extracted as a preset value.

[0024] Based on the three-dimensional simulation model of the respiratory system, a blow-through flow rate is applied to each cylinder bore;

[0025] The simulation of the piston's downward and upward movement disturbs the gas during the entire combustion cycle of the engine, and the blow-by gas velocity in the blow-by port is extracted.

[0026] Based on the airflow velocity in each of the aforementioned air-passing holes, adjust the cross-sectional area of ​​the air-passing holes in each of the target main bearing walls until the airflow velocity in the air-passing channels of each target main bearing wall is less than or equal to a preset velocity; wherein, when the airflow velocity in the air-passing channels of each target main bearing wall is less than or equal to the preset velocity, the cross-sectional area of ​​each of the aforementioned air-passing holes is the simulated value of the minimum cross-sectional area of ​​the corresponding air-passing channel.

[0027] Optionally, the flange is a circumferentially closed structure, or the flange is arc-shaped, with the arc-shaped flange surrounding a portion of the corresponding vent hole.

[0028] Optionally, the cross-sectional shape of the gas leakage hole is circular, elliptical, or trapezoidal.

[0029] Optionally, when the cross-section of the blow-by port is elliptical, the major axis of the elliptical blow-by port is parallel to the height direction of the engine; when the cross-section of the blow-by port is trapezoidal, the height direction of the trapezoidal blow-by port is parallel to the height direction of the engine. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the crankcase structure using the method for determining the crankcase blow-through hole structure provided in this embodiment of the invention.

[0031] Figure 2 A flowchart illustrating the method for determining the crankcase blow-through hole structure provided in an embodiment of the present invention;

[0032] Figure 3 This is a partial flowchart of the method for determining the crankcase blow-through hole structure provided in an embodiment of the present invention.

[0033] Icons: 1-Target main bearing wall; 11-Air leakage hole; 12-Flanged edge. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Please combine Figure 1 and Figure 2 This embodiment provides a method for determining the structure of a crankcase blow-through hole, including:

[0036] Step S1: Obtain the total blow-by gas volume of each cylinder in the crankcase;

[0037] Step S2: Set the preset value of the minimum cross-sectional area of ​​the blow-by channel on the main bearing wall 1 of each target level. Based on the total blow-by of each cylinder and the preset value of the minimum cross-sectional area of ​​the blow-by channel on the main bearing wall 1 of each target level, perform simulation processing on the blow-by channel of the main bearing wall 1 of each target level. When the blow-by flow velocity in the blow-by channel of the main bearing wall 1 of each target level is less than or equal to the preset flow velocity, determine the simulation value of the minimum cross-sectional area of ​​the blow-by channel on the main bearing wall 1 of each target level.

[0038] For example, the simulation processing of the gas leakage channel of the main bearing wall 1 of each target can be carried out through system-level simulation, and the preset flow rate can be (10±0.5)m / s.

[0039] When the flow velocity in the blow-by channel of the target main bearing wall 1 is not the preset flow velocity, the preset value of the minimum cross-sectional area of ​​the blow-by channel on the target main bearing wall 1 is adjusted. Then, based on the total blow-by volume of each cylinder and the preset value of the minimum cross-sectional area of ​​the blow-by channel on the target main bearing wall 1 after adjustment, the blow-by channel of each target main bearing wall 1 is simulated again until the flow velocity in the blow-by channel of each target main bearing wall 1 is less than or equal to the preset flow velocity.

[0040] Step S3: Determine the initial structure of the air leakage hole 11 of the main bearing wall 1 of each target based on the simulation value of the minimum cross-sectional area of ​​the air leakage channel on each target main bearing wall 1. The initial structure of the air leakage hole 11 includes the shape and position of the air leakage hole 11.

[0041] Step S4: Determine the target structure of the vent hole 11 of the corresponding target main bearing wall 1 based on the identification results and the initial structure of the vent hole 11; wherein, the identification results characterize whether the safety factor of the corresponding target main bearing wall 1 meets the preset conditions.

[0042] It is worth noting that when the air leakage hole 11 of the target main bearing wall 1 is the target structure, the cross-sectional area of ​​the air leakage hole 11 is greater than or equal to the simulated value of the minimum cross-sectional area of ​​the air leakage channel on the corresponding target main bearing wall 1.

[0043] When determining the crankcase blow-through hole structure 11 using the method provided in this embodiment, the blow-through hole structure 11 of the crankcase is simulated based on the total blow-through volume of each cylinder and the preset value of the minimum cross-sectional area of ​​the blow-through channel on the target main bearing wall 1 of each gear. The simulated value of the minimum cross-sectional area of ​​the blow-through channel on the target main bearing wall 1 of each gear is determined when the blow-through flow velocity in the blow-through channel of each gear is less than or equal to the preset flow velocity. The initial structure of the blow-through hole 11 of each gear target main bearing wall 1 is determined based on the simulated value of the minimum cross-sectional area of ​​the blow-through channel on the target main bearing wall 1 of each gear. The target structure of the blow-through hole 11 of the corresponding target main bearing wall 1 is determined based on the identification results and the initial structure of the blow-through hole 11. This method can balance the pressure between the cylinders of the crankcase and ensure that the safety factor of the target main bearing wall 1 of each gear meets the preset conditions.

[0044] In one specific implementation, the total blow-by gas amount Q includes the corresponding leakage gas amount Q between the piston and piston rings in the cylinder block. h The leakage rate between the piston and piston rings in a single cylinder can be calculated through piston ring assembly dynamics simulation. This calculation result includes instantaneous leakage and average leakage. The maximum instantaneous leakage is selected as the leakage rate Q between the piston and piston rings. h Q h This accounts for approximately 80% of the total air leakage in the engine.

[0045] Furthermore, in another optional implementation, the total blow-by gas amount also includes the turbocharger leakage amount Q. z Air compressor leakage Q k and valve guide leakage Q d At least one of the three. Specifically, turbocharger leakage, i.e., the leakage of air from the turbocharger bearing and sealing ring clearance into the crankcase through the oil return pipe, can be measured through component testing and accounts for approximately 5% of the total engine leakage. Air compressor leakage, also measured through component testing, accounts for approximately 15% of the total engine leakage. Valve guide leakage, i.e., the leakage of air from the valve stem guide and valve stem clearance into the crankcase, accounts for approximately 1% of the total engine leakage and is negligible.

[0046] In one optional implementation, the cross-sectional shape of the blow-by port 11 is circular, elliptical, or trapezoidal. For example, when the cross-section of the blow-by port 11 is elliptical, the major axis of the elliptical blow-by port 11 is parallel to the height direction of the engine; when the cross-section of the blow-by port 11 is trapezoidal, the height direction of the trapezoidal blow-by port 11 is parallel to the height direction of the engine.

[0047] Of course, in other implementations, the cross-sectional shape of the vent 11 can also be irregular.

[0048] In one specific implementation, step S4, determining the target structure of the vent holes 11 in the main bearing wall 1 of each grade based on the identification results and the initial structure of the vent holes 11, specifically includes:

[0049] When the identification result indicates that the safety factor of the corresponding target main bearing wall 1 meets the preset conditions, the initial structure of the vent hole 11 is taken as the target structure of the vent hole 11.

[0050] When the identification result indicates that the safety factor of the corresponding target main bearing wall 1 does not meet the preset conditions, the structure of the blow-through hole 11 on the corresponding target main bearing wall 1 is reset, and the identification result of whether the safety factor of the target main bearing wall 1 after resetting the blow-through hole 11 structure is obtained; the target structure of the blow-through hole 11 of the target main bearing wall 1 is determined according to the identification result and the structure of the reset blow-through hole 11. Thus, the crankcase blow-through hole 11 structure determined by the crankcase blow-through hole structure determination method provided in this embodiment can both balance the pressure between the cylinders of the crankcase and ensure that the safety factor of the target main bearing wall 1 of each gear meets the preset conditions.

[0051] Further, in an optional implementation, when the identification result indicates that the safety factor of the corresponding target main bearing wall 1 does not meet the preset conditions, the structure of the vent hole 11 on the corresponding target main bearing wall 1 is reset, and the identification result of whether the safety factor of the target main bearing wall 1 meets the preset conditions after the vent hole 11 structure is reset is obtained; the target structure of the vent hole 11 of the target main bearing wall 1 is determined according to the identification result and the structure of the reset vent hole 11, specifically including:

[0052] Step S401: When the identification result indicates that the safety factor of the corresponding target main bearing wall 1 does not meet the preset conditions, a flange 12 is set at the opening of the corresponding vent hole 11, and the identification result of whether the safety factor of the target main bearing wall 1 meets the preset conditions after the flange 12 is set is obtained.

[0053] For example, the flange 12 can be a circumferentially closed structure, or an arc-shaped structure, with the arc-shaped flange 12 surrounding a portion of the corresponding vent hole 11. The thickness (i.e., the dimension of the flange 12 in the axial direction of the vent hole 11) and width (i.e., the dimension of the flange 12 in the radial direction of the vent hole 11) of the flange 12 can be based on simulation recommendations.

[0054] Step S402: When the identification result after setting the flange 12 indicates that the safety factor of the corresponding target main bearing wall 1 meets the preset conditions, the structure of the air leakage hole 11 after setting the flange 12 is taken as the target structure of the air leakage hole 11.

[0055] Step S403: If the identification result after setting the flange 12 indicates that the safety factor of the target main bearing wall 1 does not meet the preset conditions, then the shape and / or position of the vent hole 11 is reset, and the identification result of whether the safety factor of the target main bearing wall 1 meets the preset conditions is obtained again after resetting the structure of the vent hole 11, until the identification result indicates that the safety factor of the target main bearing wall 1 meets the preset conditions.

[0056] In one optional implementation, the safety factor of each target main bearing wall 1 includes both static strength and fatigue strength safety factors. When the static strength of the target main bearing wall 1 is greater than or equal to the preset static strength value, and the fatigue strength safety factor of the target main bearing wall 1 is greater than or equal to the preset fatigue strength safety factor value, the identification result indicates that the safety factor of the corresponding target main bearing wall 1 meets the preset conditions.

[0057] When the static strength of the target main bearing wall 1 is less than the preset static strength value, and / or the fatigue strength safety factor of the target main bearing wall 1 is less than the preset fatigue strength safety factor value, the identification result indicates that the safety factor of the corresponding target main bearing wall 1 does not meet the preset conditions.

[0058] The static strength calculation and fatigue safety factor calculation of the target main bearing wall 1 can be performed with reference to existing technology, which will not be elaborated here.

[0059] It is worth noting that the static strength calculation results need to meet the tensile strength of the target main bearing wall 1. The tensile strength of the target main bearing wall 1 is determined by the structural form of the cylinder block, the displacement of the engine, and the level of existing technology. For example, in one specific implementation, the tensile strength of the target main bearing wall 1 is greater than or equal to 220 MPa.

[0060] The fatigue safety factor needs to be checked to see if the fatigue safety factor obtained from the global model simulation meets the limit requirement of 1.1, and whether the fatigue safety factor of the sub-model meets the limit requirement of 1.05.

[0061] When both the fatigue safety factor and static strength requirements are met, the structure of the vent hole 11 is the target structure. In one specific implementation, if the fatigue safety factor obtained from the global model simulation of the corresponding target main bearing wall 1 is greater than or equal to the limit requirement of 1.1, and the fatigue safety factor of the sub-model is greater than or equal to the limit requirement of 1.05, then it is considered that the fatigue strength safety factor of the target main bearing wall 1 is greater than or equal to the preset value of the fatigue strength safety factor.

[0062] In another specific implementation, if the fatigue safety factor of the sub-model is greater than or equal to the limit requirement of 1.05, then it is considered that the fatigue strength safety factor of the target main bearing wall 1 is greater than or equal to the preset value of the fatigue strength safety factor.

[0063] In one alternative implementation, such as Figure 3 As shown, step S2 involves setting a preset value for the minimum cross-sectional area of ​​the blow-by passage on the target main bearing wall 1 for each gear. Based on the total blow-by volume of each cylinder and the preset value for the minimum cross-sectional area of ​​the blow-by passage on the target main bearing wall 1 for each gear, the blow-by passage of the target main bearing wall 1 for each gear is simulated. When the blow-by flow velocity in the blow-by passage of the target main bearing wall 1 for each gear is less than or equal to the preset flow velocity, the simulated value for the minimum cross-sectional area of ​​the blow-by passage on the target main bearing wall 1 for each gear is determined. Specifically, this includes:

[0064] Step S21: Extract the three-dimensional simulation model of the respiratory system when the minimum cross-sectional area of ​​the air leakage channel on the main bearing wall 1 of each target gear is a preset value. That is, the airflow channel model inside the crankcase when the minimum cross-sectional area of ​​the air leakage channel on the main bearing wall 1 of each target gear is a preset value. The three-dimensional simulation model of the respiratory system can be obtained by removing (i.e., subtracting) the non-airflow channel model from the maximum boundary model.

[0065] The maximum boundary model is the sum of the cylinder core model and the oil pan cavity model of the cylinder block. For the truss engine block, it also includes the truss sand core model. The non-airflow channel model, i.e., the structural component model within the crankcase, includes the crankshaft and connecting rod structure model, the oil model stored in the oil pan during engine operation, and the oil filter piping and support model, etc. The influence of peripheral piping is relatively small and can be ignored when establishing the simulation model.

[0066] Step S22: Apply blow-by flow rate to each cylinder bore based on the three-dimensional simulation model of the respiratory system, where Q z and Q k The steady-state value, that is, a constant value, is Q. h This represents the maximum calculated leakage rate of a single-cylinder piston. For example, the maximum calculated leakage rate of a single-cylinder piston for a certain engine model is 19.62 L / min.

[0067] Step S23: Simulate the disturbance of gas caused by the piston's downward and upward movement during the entire combustion cycle of the engine, and extract the flow velocity in the blow-by port 11.

[0068] Taking a four-cylinder engine as an example, calculate the disturbance of airflow in the crankcase caused by the piston's downward and upward movements within a 720° turning angle.

[0069] Step S24: Adjust the cross-sectional area of ​​the blow-through hole 11 of each target main bearing wall 1 according to the blow-through air velocity in the blow-through hole 11 until the blow-through air velocity between the crankcase cylinders is less than or equal to the preset velocity; wherein, when the blow-through air velocity between the crankcase cylinders is less than or equal to the preset velocity, the cross-sectional area of ​​the blow-through hole 11 is the simulated value of the minimum cross-sectional area of ​​the blow-through channel.

[0070] In related technologies, due to the overall layout requirements of the engine, the oil return points of the turbocharger and air compressor are sometimes arranged in the crankcase of the same cylinder. Because the oil and gas contain gas, the oil and gas pressure in this cylinder is significantly higher than that in other cylinders. When determining the crankcase blow-through hole structure 11 using the method provided in this embodiment, it is possible to ensure uniform crankcase pressure among cylinders while maximizing the safety factor of the target main bearing wall 1.

[0071] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for determining the structure of a crankcase blow-through hole, characterized in that, include: Obtain the total blow-by gas volume of each cylinder in the crankcase; Set a preset value for the minimum cross-sectional area of ​​the blow-by channel on the main bearing wall of each target level. Based on the total blow-by volume of each cylinder and the preset value for the minimum cross-sectional area of ​​the blow-by channel on the main bearing wall of each target level, perform simulation processing on the blow-by channel of the main bearing wall of each target level. When the blow-by flow velocity in the blow-by channel of the main bearing wall of each target level is less than or equal to the preset flow velocity, determine the simulation value of the minimum cross-sectional area of ​​the blow-by channel on the main bearing wall of each target level. The initial structure of the air leakage hole in the main bearing wall of each target grade is determined based on the simulation value of the minimum cross-sectional area of ​​the air leakage channel on the wall of each target grade. The initial structure of the air leakage hole includes the shape and position of the air leakage hole. Based on the identification results and the initial structure of the air leakage hole, the target structure of the corresponding air leakage hole in the target main bearing wall is determined; wherein, the identification results characterize whether the safety factor of the corresponding target main bearing wall meets the preset conditions; The preset value for the minimum cross-sectional area of ​​the blow-by channel on the main bearing wall of each target bearing is set. Based on the total blow-by volume of each cylinder and the preset value for the minimum cross-sectional area of ​​the blow-by channel on the main bearing wall of each target bearing, the blow-by channel of each target bearing is simulated. When the blow-by velocity in the blow-by channel of each target bearing is less than or equal to the preset velocity, the simulated value for the minimum cross-sectional area of ​​the blow-by channel on the main bearing wall of each target bearing is determined. Specifically, this includes: The three-dimensional simulation model of the respiratory system is obtained when the minimum cross-sectional area of ​​the air leakage channel on the wall of the target main bearing for each grade is extracted as a preset value. Based on the three-dimensional simulation model of the respiratory system, a blow-through flow rate is applied to each cylinder bore; The simulation of the piston's downward and upward movement disturbs the gas during the entire combustion cycle of the engine, and the blow-by gas velocity in the blow-by port is extracted. Based on the airflow velocity in each of the aforementioned air-passing holes, adjust the cross-sectional area of ​​the air-passing holes in each of the target main bearing walls until the airflow velocity in the air-passing channels of each target main bearing wall is less than or equal to a preset velocity; wherein, when the airflow velocity in the air-passing channels of each target main bearing wall is less than or equal to the preset velocity, the cross-sectional area of ​​each of the aforementioned air-passing holes is the simulated value of the minimum cross-sectional area of ​​the corresponding air-passing channel.

2. The method for determining the crankcase blow-through hole structure according to claim 1, characterized in that, The step of determining the target structure of the corresponding vent hole in the target main bearing wall based on the identification result and the initial structure of the vent hole specifically includes: When the identification result indicates that the safety factor of the corresponding target main bearing wall meets the preset conditions, the initial structure of the air leakage hole is taken as the target structure of the air leakage hole; When the identification result indicates that the safety factor of the target main bearing wall does not meet the preset conditions, the air leakage hole structure on the target main bearing wall is reset, and the identification result of whether the safety factor of the target main bearing wall meets the preset conditions after the air leakage hole structure is reset is obtained; the target structure of the air leakage hole of the target main bearing wall is determined according to the identification result and the reset structure of the air leakage hole.

3. The method for determining the crankcase blow-through hole structure according to claim 2, characterized in that, When the identification result indicates that the safety factor of the corresponding target main bearing wall does not meet the preset conditions, the air leakage hole structure on the corresponding target main bearing wall is reset, and the identification result of whether the safety factor of the target main bearing wall meets the preset conditions after the air leakage hole structure is reset is obtained. Based on the identification results and the reconfigured structure of the vent hole, the target structure of the vent hole in the target main bearing wall is determined, specifically including: When the identification result indicates that the safety factor of the target main bearing wall does not meet the preset conditions, a flange is set at the opening of the corresponding air leakage hole, and the identification result of whether the safety factor of the target main bearing wall meets the preset conditions after the flange is set is obtained. When the identification result after setting the flange indicates that the safety factor of the corresponding target main bearing wall meets the preset conditions, the structure of the air leakage hole after setting the flange is taken as the target structure of the air leakage hole. If the identification result after setting the flange indicates that the safety factor of the target main bearing wall does not meet the preset conditions, then the shape and / or position of the vent hole is reset, and the identification result of whether the safety factor of the target main bearing wall meets the preset conditions after resetting the vent hole structure is obtained again, until the identification result indicates that the safety factor of the target main bearing wall meets the preset conditions.

4. The method for determining the crankcase blow-through hole structure according to any one of claims 1-3, characterized in that, The safety factor of the target main bearing wall in each grade includes both static strength and fatigue strength safety factors. When the static strength of the target main bearing wall is greater than or equal to the preset static strength value, and the fatigue strength safety factor of the target main bearing wall is greater than or equal to the preset fatigue strength safety factor value, the identification result indicates that the safety factor of the corresponding target main bearing wall meets the preset conditions. When the static strength of the target main bearing wall is less than the preset static strength value, and / or the fatigue strength safety factor of the target main bearing wall is less than the preset fatigue strength safety factor value, the identification result indicates that the safety factor of the corresponding target main bearing wall does not meet the preset condition.

5. The method for determining the crankcase blow-through hole structure according to any one of claims 1-3, characterized in that, The total amount of blow-by includes the amount of air leakage between the piston and piston rings in the corresponding cylinder.

6. The method for determining the crankcase blow-through hole structure according to claim 5, characterized in that, The total amount of blow-by gas also includes at least one of the following: turbocharger leakage, air compressor leakage, and valve guide leakage.

7. The method for determining the crankcase blow-through hole structure according to claim 3, characterized in that, The flange is a circumferentially closed structure, or the flange is arc-shaped, with the arc-shaped flange surrounding a portion of the corresponding air leakage hole.

8. The method for determining the crankcase blow-through hole structure according to any one of claims 1-3, characterized in that, The cross-sectional shape of the gas leakage hole is circular, elliptical, or trapezoidal.

9. The method for determining the crankcase blow-through hole structure according to claim 8, characterized in that, When the cross-section of the blow-by port is elliptical, the major axis of the elliptical blow-by port is parallel to the height direction of the engine; when the cross-section of the blow-by port is trapezoidal, the height direction of the trapezoidal blow-by port is parallel to the height direction of the engine.

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