Method and device for assessing the oil-gas separation capacity of a crankcase ventilation system

Abstract

The present application provides a method and device for evaluating the oil-gas separation capability of a crankcase ventilation system, the method comprising the steps of: operating a target engine at a corresponding target operating condition to produce a first blow-by gas having a corresponding first flow rate; operating a supply engine at a corresponding supply operating condition together with the target engine to produce a second blow-by gas, the second blow-by gas flowing from a second crankcase to a first crankcase at a corresponding second flow rate to flow together with the first blow-by gas from the first crankcase to a first intake manifold via a first part-load breather pipe and a first full-load breather pipe, while a first oil collection bottle and a second oil collection bottle collect oil present in the first blow-by gas and the second blow-by gas; and evaluating the oil-gas separation capability of the crankcase ventilation system at the corresponding target operating condition based on a sum of the corresponding first flow rate and the corresponding second flow rate when oil appears in at least one of the first oil collection bottle and the second oil collection bottle.

Description

Technical Field

[0001] This application relates to the technical field of evaluating the oil-gas separation capability of a crankcase ventilation system, and more specifically to a method and apparatus for evaluating the oil-gas separation capability of a crankcase ventilation system. Background Technology

[0002] As is well known, when an engine is running, some unburned air-fuel mixture and exhaust gases leak into the crankcase through the gap between the piston rings and cylinders, forming piston leakage. This piston leakage mixes with hot engine oil splashed in the crankcase, forming blow-by gas. This blow-by gas then enters the crankcase ventilation system, such as a crankcase forced ventilation system. In this system, the engine oil in the blow-by gas is filtered out and flows back to the oil pan through the oil return port. The filtered blow-by gas then enters the combustion chamber through the full-load breather, partial-load breather, and intake manifold to re-particulate in combustion. The oil-gas separation function of the crankcase ventilation system not only increases the service life of the engine oil and reduces particulate emissions and environmental pollution, but also extends engine life to a certain extent.

[0003] However, as the engine ages and wears, the clearance between the piston rings and cylinders widens, increasing the flow rate and velocity of piston leakage. Consequently, the amount of oil carried in the blow-by gas also increases, making oil-gas separation more difficult. If the crankcase ventilation system is poorly designed with inadequate oil-gas separation capabilities, a large amount of oil will ultimately flow into the combustion chamber and participate in combustion. This can cause knocking, carbon buildup, and coking, or even engine delusion and damage to friction pairs. Furthermore, the oil-gas separation capabilities of different crankcase ventilation system designs are a key focus for engineers during the design process.

[0004] Therefore, in the bench test of the crankcase ventilation system, it is necessary to evaluate the oil-gas separation capability of the crankcase ventilation system, and blow-by flow rate is an important variable for evaluating the oil-gas separation capability of the crankcase ventilation system.

[0005] Currently, the increased blow-by gas flow is mainly simulated by adding air to the crankcase. However, the composition of air is very different from that of blow-by gas, and it cannot accurately represent the impact of blow-by gas flow on the oil-gas separation capability of the crankcase ventilation system. Summary of the Invention

[0006] One objective of this application is to provide a method and apparatus for evaluating the oil-gas separation capability of a crankcase ventilation system, which can be used to evaluate the oil-gas separation capability of the crankcase ventilation system after an increase in blow-by gas in the crankcase, providing support for product design and optimization, and ensuring vehicle safety.

[0007] According to one aspect of this application, a method is provided for evaluating the oil-gas separation capability of a crankcase ventilation system, the crankcase ventilation system being part of a target engine and including a first crankcase, a first partial-load breather, and a first full-load breather. The target engine also includes a first intake manifold fluidly connected to the first crankcase via the first partial-load breather and the first full-load breather. The method includes the steps of: providing an air-supplying engine including a second crankcase; fluidly connecting the second crankcase in series to the first crankcase; fluidly connecting a first oil collector in series to the first partial-load breather; fluidly connecting a second oil collector in series to the first full-load breather; and causing the target engine to... The engine operates under a corresponding target operating condition to generate a first blow-by gas with a corresponding first flow rate; the gas-supplying engine operates under a corresponding gas-supply operating condition in conjunction with the target engine to generate a second blow-by gas, the second blow-by gas flowing from the second crankcase to the first crankcase with a corresponding second flow rate, and flowing together with the first blow-by gas from the first crankcase to the first intake manifold via a first partial-load breather and a first full-load breather, while a first oil collector and a second oil collector collect the engine oil present in the first and second blow-by gases; and the oil-gas separation capability of the crankcase ventilation system under the corresponding target operating condition is evaluated based on the sum of the corresponding first flow rate and the corresponding second flow rate when engine oil is present in at least one of the first and second oil collectors.

[0008] Optionally, the gas-supply engine further includes a second partial-load breather pipe and a second full-load breather pipe, and a second intake manifold fluidly connected to the second crankcase via the second partial-load breather pipe and the second full-load breather pipe, wherein the step of fluidly connecting the second crankcase in series to the first crankcase includes: disconnecting the fluid connection between the second crankcase and the second intake manifold; and fluidly connecting the second crankcase to the first crankcase via an additional pipe.

[0009] Optionally, the step of disconnecting the fluid communication between the second crankcase and the second intake manifold includes: removing the second partial load breather and the second full load breather; and sealing the port of the second crankcase for connection to the second partial load breather; and the step of making the second crankcase fluidly connected to the first crankcase by means of an additional pipe includes: opening an installation interface on the first crankcase; and connecting the additional pipe to the installation interface and the port of the second crankcase for connection to the second full load breather.

[0010] Optionally, a flow regulating device is provided in the auxiliary pipe to regulate the second blow-by gas flowing from the second crankcase to the first crankcase to a corresponding second flow rate.

[0011] Optionally, the flow regulating device is configured to regulate a corresponding second flow based on a corresponding first flow, such that the sum of the corresponding first flow and the corresponding second flow is equal to one of a plurality of preset flow rates designed to evaluate the oil-gas separation capability of the crankcase ventilation system under a corresponding target operating condition.

[0012] Optionally, the original flow rate of the second blow-by gas generated when the gas-supply engine operates under the corresponding gas supply conditions is greater than or equal to the maximum flow rate of blow-by gas that the crankcase ventilation system can withstand under the corresponding target conditions.

[0013] Optionally, before connecting the second crankcase in series with the first crankcase, the different initial flow rates of the second blow-by gas generated when the gas-supply engine is operating under different gas supply conditions are measured.

[0014] Optionally, before connecting the second crankcase in series with the first crankcase, the different first flow rates of the first blow-by gas generated by the target engine under different target operating conditions are measured.

[0015] Optionally, different target operating conditions characterize different speeds and different loads of the target engine.

[0016] According to another aspect of this application, an apparatus is provided for evaluating the oil-gas separation capability of a crankcase ventilation system, the crankcase ventilation system forming part of a target engine and including a first crankcase, a first partial-load breather, and a first full-load breather. The target engine also includes a first intake manifold fluidly connected to the first crankcase via the first partial-load breather and the first full-load breather. The apparatus is configured to perform a method for evaluating the oil-gas separation capability of the crankcase ventilation system. The apparatus includes: a supply engine including a second crankcase, wherein the second crankcase is fluidly connected in series to the first crankcase; a first oil collection bottle fluidly connected in series to the first partial-load breather; and a second oil collection bottle fluidly connected in series to the first full-load breather. ; and a controller configured to: operate a target engine under a corresponding target operating condition to generate a first blow-by gas with a corresponding first flow rate; operate a supply engine under a corresponding supply operating condition in conjunction with the target engine to generate a second blow-by gas, the second blow-by gas flowing from a second crankcase to a first crankcase at a corresponding second flow rate, and flowing together with the first blow-by gas from the first crankcase to a first intake manifold via a first partial load breather and a first full load breather, while a first oil collector and a second oil collector collect oil present in the first and second blow-by gases; and evaluate the oil-gas separation capability of the crankcase ventilation system under the corresponding target operating condition based on the sum of the corresponding first flow rate and the corresponding second flow rate when oil is present in at least one of the first and second oil collectors.

[0017] The method and apparatus provided in this application for evaluating the oil-gas separation capability of a crankcase ventilation system utilize a gas-supplying engine to provide realistic blow-by gas, thus better simulating the actual situation of increased piston leakage flow due to engine wear and aging. Furthermore, it improves the convenience of testing and reduces testing costs.

[0018] Other features and advantages of this application will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0019] The accompanying drawings, which form part of this specification, illustrate embodiments of this application and, together with the specification, serve to explain the principles of this application.

[0020] Figure 1 This is a schematic diagram of an apparatus for evaluating the oil-gas separation capability of a crankcase ventilation system according to one embodiment of this application, and a target engine equipped with the apparatus.

[0021] Figure 2 This is a flowchart of a method for evaluating the oil-gas separation capability of a crankcase ventilation system according to one embodiment of this application. Detailed Implementation

[0022] Various exemplary embodiments of this application will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of this application.

[0023] Techniques, devices, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, devices, and equipment should be considered part of the specification.

[0024] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary implementations may have different values.

[0025] In this article, "upstream" and "downstream" are both relative to the direction of cross-flow of gas, which will be described in detail below.

[0026] A method for evaluating the oil-gas separation capability of a crankcase ventilation system according to one embodiment of this application (hereinafter referred to as the evaluation method) can be used to evaluate the oil-gas separation capability of the crankcase ventilation system of a target engine 100. For example... Figure 1 As shown, the exemplary target engine 100 mainly includes: multiple cylinders, in Figure 1Only one cylinder 12 is schematically shown; a piston 14 reciprocating within each cylinder; a crankshaft 16 connected to the piston 14; a crankcase ventilation system; and a first intake manifold 18 from which air-containing intake air enters the cylinder to form an air-fuel mixture with fuel injected by a fuel injector (not shown). The air-fuel mixture burns within the cylinder, causing the piston 14 to reciprocate within the cylinder 12, which in turn causes the crankshaft 16 to rotate, generating drive torque.

[0027] An exemplary crankcase ventilation system includes: a first crankcase 20, in which a crankshaft 16 is housed; an oil-gas separator (not shown) integrated into the first crankcase 20; a first part-load breather 22; a first full-load breather 24; and an air filter 26, which is fluidly connected to a first intake manifold 18 via a first intake line 28 to supply filtered air to the first intake manifold 18, the amount of air entering the first intake manifold 18 being controlled by a throttle valve 30 disposed in the first intake line 28. The first crankcase 20 has a first interface 32 for connecting to the first part-load breather 22 and a second interface 34 for connecting to the first full-load breather 24, wherein the first interface 32 and the second interface 34 are located downstream of the oil-gas separator. Correspondingly, the first intake manifold 18 has a third interface 36 for connecting to the first part-load breather 22, the third interface 36 being located downstream of the throttle valve 30. Additionally, the first intake manifold 28 is also provided with a fourth port 38 for connecting to the first full-load breathing manifold 24, wherein the fourth port 38 is located between the throttle valve 30 and the first air filter 26. Thus, the first partial-load breathing manifold 22 can be connected to the first port 32 and the third port 36 respectively to fluidly connect the first crankcase 20 to the first intake manifold 18, while the first full-load breathing manifold 24 can be connected to the second port 34 and the fourth port 38 respectively to fluidly connect the first crankcase 20 to the first intake manifold 28 and, consequently, to the first intake manifold 18.

[0028] When the target engine 100 operates under different conditions (e.g., different speeds, different torques, etc.), a portion of the high-pressure air-fuel mixture in cylinder 12 leaks into the first crankcase 20 through the gap between the piston rings of piston 14 and cylinder 12, forming piston leakage. This piston leakage mixes with splashed high-temperature engine oil to form blow-by gas. In addition to engine oil, blow-by gas also includes unburned air-fuel mixture, water vapor, and exhaust gases from combustion, making its composition quite complex.

[0029] On the one hand, the crankcase ventilation system can filter the blow-by gas flowing from the first crankcase 20 using an oil-gas separator, and guide the oil separated from the blow-by gas back to the oil pan, preventing the oil from directly entering the cylinder 12 for combustion and generating a large amount of carbon soot particles, which would affect the power and emissions of the target engine 100. On the other hand, the crankcase ventilation system can send the filtered blow-by gas to the first intake manifold 18 using the first partial-load breather pipe 22 and the first full-load breather pipe 24, so that the filtered blow-by gas can be recycled. Therefore, it is necessary to pay attention to the oil-gas separation capability of the crankcase ventilation system to ensure the normal, safe, and efficient operation of the target engine 100.

[0030] The apparatus for evaluating the oil-gas separation capability of a crankcase ventilation system (hereinafter referred to as the evaluation apparatus) proposed in this application can be used to perform bench tests on the crankcase ventilation system of a target engine 100 to effectively evaluate whether the design of the crankcase ventilation system meets the requirements and provide support for the development and improvement of parts. Moreover, such an evaluation apparatus can improve the convenience of testing and reduce testing costs.

[0031] Continue to refer to Figure 1 The exemplary evaluation device mainly includes a gas supply engine 200, whose important function is to supplement blow-by gas to the crankcase ventilation system of the target engine 100. In the following text, for ease of distinction, the blow-by gas generated when the target engine 100 is operating is referred to as the first blow-by gas, and the blow-by gas generated when the gas supply engine 200 is operating is referred to as the second blow-by gas.

[0032] Similar in structure to or identical to the exemplary target engine 100, the air supply engine 200 includes a second crankcase 40, a second partial-load breather (not shown), a second full-load breather (not shown), and a second intake manifold 42. The second crankcase 40 has a first port 44 (indicated by a dot) for connection to the second partial-load breather and a second port 46 for connection to the second full-load breather. The second intake manifold 42 correspondingly has a third port 48 (indicated by a dot) for connection to the second partial-load breather. The second intake line 43 also correspondingly has a fourth port 50 (indicated by a dot) for connection to the second full-load breather.

[0033] To allow the second blow-by gas generated during the operation of the air supply engine 200 to flow from the second crankcase 40 to the first crankcase 20, the second crankcase 40 needs to be fluidly connected to the first crankcase 20. For this purpose, the air supply engine 200 requires minor modifications. First, the fluid connection between the second crankcase 40 and the second intake manifold 42 is disconnected, for example, by removing the second partial-load breather and the second full-load breather, and sealing the first port 44, the third port 48, and the fourth port 50. Then, the second crankcase 40 is fluidly connected to the first crankcase 20 by means of an additional pipe 54, for example, by creating a mounting port 52 on the first crankcase 20 and connecting the additional pipe 54 to the mounting port 52 and the second port 46, respectively. Optionally, a hole can be drilled near the bottom of the first crankcase 20 to provide the mounting port 52; it is understood that the location of the mounting port 52 is not limited to this.

[0034] Optionally, a flow regulating device 56 is provided in the auxiliary pipe 54 to regulate the flow rate of the second blow-by gas flowing from the second crankcase 40 to the first crankcase 20 via the auxiliary pipe 54. For example, the flow regulating device 56 may be a flow meter with a bypass valve or a flow regulating valve.

[0035] Understandably, corresponding sensors are installed at various components of the target engine 100 to continuously detect variables related to the operating state of the target engine 100, thereby determining whether the target engine 100 is operating normally. For example, the oil temperature in the oil pan, the oil temperature in the main oil passage, the temperature of the inlet and outlet water used to cool the target engine 100, the oil pressure in the main oil passage fluidly connected to the oil pump, and the gas pressure in the crankcase can be detected.

[0036] An exemplary assessment apparatus also includes a first oil collection bottle 58 which is in series fluid communication with the first partial load breathing tube 22 and a second oil collection bottle 60 which is in series fluid communication with the first full load breathing tube 24.

[0037] like Figure 2 As shown, the exemplary evaluation method implemented by the exemplary evaluation apparatus includes the following steps:

[0038] S100. Provides an air-supply engine 200 including a second crankcase 40;

[0039] S110. The second crankcase 40 is connected in series with the first crankcase 20 in fluid communication;

[0040] S120. Connect the first oil collection bottle 58 in series to the first partial load breathing tube 22 in a fluid manner;

[0041] S130. Connect the second oil collection bottle 60 in series to the first full-load breathing tube 24 in a fluid connection;

[0042] S140. The target engine 100 is operated under the corresponding target operating conditions to generate a first blow-by gas with a corresponding first flow rate;

[0043] S150. The air-supplying engine 200 operates in conjunction with the target engine 100 under a corresponding air-supply condition to generate a second blow-by gas. The second blow-by gas flows from the second crankcase 40 to the first crankcase 20 at a corresponding second flow rate, and together with the first blow-by gas, flows from the first crankcase 20 to the first intake manifold 18 via the first partial-load breather pipe 22 and the first full-load breather pipe 24. Simultaneously, the first oil collector 58 and the second oil collector 60 collect the engine oil present in the first and second blow-by gases; and

[0044] S160. Evaluate the oil-gas separation capability of the crankcase ventilation system under the corresponding target operating condition based on the sum of the corresponding first flow rate and the corresponding second flow rate when oil appears in at least one of the first oil collection bottle 58 and the second oil collection bottle 60.

[0045] It is worth noting that, since the exemplary evaluation methods provided in this application are intended to be performed using exemplary evaluation apparatus, the features of the exemplary evaluation methods and the features of the exemplary evaluation apparatus described herein may correspond to, combine with, and be interchanged with each other.

[0046] Alternatively, the above steps can be performed in a different manner. Figure 2 The order in which they occur is indicated. For example, Figure 2 Two consecutive boxes can actually be executed in largely parallel order, or sometimes in reverse order, depending on the steps involved.

[0047] Table 1 schematically illustrates the variables required to set up and obtain for evaluating the oil-gas separation capability of a crankcase ventilation system under different target operating conditions using an exemplary evaluation method. In the bench test, the speed and load of the target engine 100 can be controlled by a controller to obtain different first flow rates of the first blow-by gas at different speeds and loads of the target engine 100.

[0048] Table 1

[0049]

[0050] Optionally, the flow regulating device 56 is configured to adjust a corresponding second flow rate based on a corresponding first flow rate, such that the sum of the corresponding first and second flow rates equals one of a plurality of preset flow rates designed to evaluate the oil-gas separation capability of the crankcase ventilation system under a corresponding target operating condition. For example, the plurality of preset flow rates may be stepped or continuously increasing to observe whether, after the target engine 100 operates at each of the plurality of preset flow rates for a period of time (e.g., half an hour) under the corresponding target operating condition, oil traces, such as those visible to the naked eye or detectable by sensors, appear in at least one of the first oil collection bottle 58 and the second oil collection bottle 60, thereby evaluating the oil-gas separation capability of the crankcase ventilation system under the corresponding target operating condition. For example, the sum of the corresponding first and second flow rates when oil appears in at least one of the first and second oil collection bottles 58 and 60 can be used as the maximum blow-by flow rate that the target engine 100 can withstand under the corresponding target operating condition.

[0051] Understandably, when the sum of the corresponding first flow rate and the corresponding second flow rate equals the last preset flow rate among the plurality of preset flow rates, if no engine oil is present in either the first oil collection bottle 58 or the second oil collection bottle 60, then the oil-gas separation capability of the crankcase ventilation system under the corresponding target operating condition is evaluated as excellent. Therefore, the last preset flow rate is the maximum flow rate of blow-by gas that the target engine 100 can withstand under the corresponding target operating condition.

[0052] Optionally, to ensure that the sum of the corresponding first flow rate of the first blow-by gas flowing through the first partial load breathing tube 22 and the first full load breathing tube 24 reaches the last preset flow rate, the corresponding original flow rate of the second blow-by gas generated by the air supply engine 200 when operating under the corresponding air supply condition should be greater than or equal to the last preset flow rate. In other words, the corresponding air supply condition of the air supply engine 200 is determined based on the corresponding target condition of the target engine 100, so that the corresponding original flow rate of the second blow-by gas can reach the last preset flow rate independently. Then, the corresponding original flow rate of the second blow-by gas is adjusted to the corresponding second flow rate by the flow regulating device 56, so that the second blow-by gas is delivered from the second crankcase 40 to the first crankcase 20 at the corresponding second flow rate.

[0053] Optionally, before connecting the second crankcase 40 in series with the first crankcase 20, the different first flow rates of the first blow-by gas generated by the target engine 100 under different target operating conditions can be measured in advance. When the target engine 100 operates under the corresponding target operating conditions at a speed and load controlled by the controller, the corresponding first flow rate of the first blow-by gas under the corresponding target operating conditions of the target engine 100 can be obtained directly by looking up the table shown in Table 2.

[0054] Table 2

[0055]

[0056] Optionally, before connecting the second crankcase 40 in series with the first crankcase 20, the different original flow rates of the second blow-by gas generated when the gas supply engine 200 operates under different gas supply conditions can be measured in advance. When the gas supply engine 200 operates under the corresponding gas supply conditions at the speed and load controlled by the controller, the corresponding original flow rate of the second blow-by gas under the corresponding gas supply conditions of the gas supply engine 200 can be obtained directly by looking up the table shown in Table 3.

[0057] Table 3

[0058]

[0059] It is understandable that different operating conditions should at least include the maximum torque point and rated power point of the target engine 100, and different operating conditions should cover the full-load operating state and the partial-load operating state of the target engine 100.

[0060] For example, when the speed and torque of the target engine 100 are controlled by the controller to simulate the full-load working state of the target engine 100 when the accelerator pedal is fully depressed or the throttle opening is 100%, the presence of oil in the second oil collection bottle 60 can be selectively observed or sensed to evaluate the oil-gas separation capability of the crankcase ventilation system, especially in relation to the first full-load breather pipe 24.

[0061] For example, when the speed and torque of the target engine 100 are controlled by the controller to simulate the partial load operation of the target engine 100 when the accelerator pedal is not fully depressed or the throttle opening is greater than 0 and less than 100%, for example, when the target engine 100 is running at low speed and low load, the presence of oil in the first oil collection bottle 58 can be selectively observed or sensed to evaluate the oil-gas separation capability of the crankcase ventilation system, especially related to the first partial load breather pipe 22.

[0062] While some specific embodiments of this application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of this application. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this application. The scope of this application is defined by the appended claims.

Claims

1. A method for evaluating the oil-gas separation capability of a crankcase ventilation system, the crankcase ventilation system constituting part of a target engine (100) and including a first crankcase (20), a first partial-load breather (22), and a first full-load breather (24), the target engine (100) further including a first intake manifold (18) fluidly connected to the first crankcase (20) via the first partial-load breather (22) and the first full-load breather (24), characterized in that, The method includes the following steps: A gas-powered engine (200) including a second crankcase (40) is provided; The second crankcase (40) is fluidly connected in series to the first crankcase (20); The first oil collection bottle (58) is connected in series to the first partial load breathing tube (22); The second oil collection bottle (60) is connected in series to the first full-load breathing tube (24); The target engine (100) is made to operate under the corresponding target conditions to generate a first blow-by gas with a corresponding first flow rate; The gas-supply engine (200) operates in conjunction with the target engine (100) under corresponding gas supply conditions to generate a second blow-by gas. This second blow-by gas flows from the second crankcase (40) to the first crankcase (20) at a corresponding second flow rate, and together with the first blow-by gas, flows from the first crankcase (20) to the first intake manifold (18) via the first partial-load breather pipe (22) and the first full-load breather pipe (24). Simultaneously, the first oil collector (58) and the second oil collector (60) collect the oil present in the first and second blow-by gases; and The oil-gas separation capability of the crankcase ventilation system under the corresponding target operating condition is evaluated based on the sum of the corresponding first flow rate and the corresponding second flow rate when oil is present in at least one of the first oil collection bottle (58) and the second oil collection bottle (60).

2. The method for evaluating the oil-gas separation capability of a crankcase ventilation system according to claim 1, characterized in that, The gas-powered engine (200) also includes a second partial-load breather and a second full-load breather, and a second intake manifold (42) fluidly connected to the second crankcase (40) via the second partial-load breather and the second full-load breather, wherein the step of fluidly connecting the second crankcase (40) in series to the first crankcase (20) includes: Disconnect the fluid connection between the second crankcase (40) and the second intake manifold (42); and The second crankcase (40) is fluidly connected to the first crankcase (20) by means of an additional pipe (54).

3. The method for evaluating the oil-gas separation capability of a crankcase ventilation system according to claim 2, characterized in that, The steps of disconnecting the fluid communication between the second crankcase (40) and the second intake manifold (42) include: Remove the second partial load breathing tube and the second full load breathing tube; and Seal the port of the second crankcase (40) for connection to the second partial load breathing tube; and The steps of fluidly connecting the second crankcase (40) to the first crankcase (20) by means of an additional pipe (54) include: An installation interface (52) is provided on the first crankcase (20); and Connect the additional tube (54) to the mounting interface (52) and the port of the second crankcase (40) for connecting to the second full-load breathing tube.

4. The method for evaluating the oil-gas separation capability of a crankcase ventilation system according to claim 2 or 3, characterized in that, A flow regulating device (56) is provided in the auxiliary pipe (54) to regulate the second blow-by gas flowing from the second crankcase (40) to the first crankcase (20) to a corresponding second flow rate.

5. The method for evaluating the oil-gas separation capability of a crankcase ventilation system according to claim 4, characterized in that, The flow regulating device (56) is configured to regulate a corresponding second flow based on a corresponding first flow, such that the sum of the corresponding first flow and the corresponding second flow is equal to one of a plurality of preset flow rates designed to evaluate the oil-gas separation capability of the crankcase ventilation system under a corresponding target operating condition.

6. The method for evaluating the oil-gas separation capability of a crankcase ventilation system according to any one of claims 1 to 5, characterized in that, The original flow rate of the second blow-by gas generated when the gas-supply engine (200) operates under the corresponding gas supply conditions is greater than or equal to the maximum flow rate of blow-by gas that the crankcase ventilation system can withstand under the corresponding target conditions.

7. The method for evaluating the oil-gas separation capability of a crankcase ventilation system according to claim 6, characterized in that, Before connecting the second crankcase (40) in series with the first crankcase (20), the different original flow rates of the second blow-by gas generated by the gas-supply engine (200) under different gas supply conditions are measured.

8. The method for evaluating the oil-gas separation capability of a crankcase ventilation system according to any one of claims 1 to 7, characterized in that, Before connecting the second crankcase (40) in series with the first crankcase (20), measure the different first flow rates of the first blow-by gas generated by the target engine (100) under different target operating conditions.

9. The method for evaluating the oil-gas separation capability of a crankcase ventilation system according to claim 8, characterized in that, Different target operating conditions characterize different speeds and different loads of the target engine (100).

10. An apparatus for evaluating the oil-gas separation capability of a crankcase ventilation system, the crankcase ventilation system forming part of a target engine (100) and including a first crankcase (20), a first partial-load breather (22), and a first full-load breather (24), the target engine (100) further including a first intake manifold (18) fluidly connected to the first crankcase (20) by means of the first partial-load breather (22) and the first full-load breather (24), the apparatus being configured to perform the method according to any one of claims 1 to 9, characterized in that, The device includes: An air-supplying engine (200) including a second crankcase (40), wherein the second crankcase (40) is in series fluid communication with the first crankcase (20); The first oil collection bottle (58) is connected in series with the first part-load breathing tube (22) in fluid communication; A second oil collection bottle (60) is connected in series with the first full-load breathing tube (24) in fluid communication; and The controller is configured as follows: The target engine (100) is made to operate under the corresponding target conditions to generate a first blow-by gas with a corresponding first flow rate; The gas-supply engine (200) operates in conjunction with the target engine (100) under corresponding gas supply conditions to generate a second blow-by gas. This second blow-by gas flows from the second crankcase (40) to the first crankcase (20) at a corresponding second flow rate, and together with the first blow-by gas, flows from the first crankcase (20) to the first intake manifold (18) via the first partial-load breather pipe (22) and the first full-load breather pipe (24). Simultaneously, the first oil collector (58) and the second oil collector (60) collect the oil present in the first and second blow-by gases; and The oil-gas separation capability of the crankcase ventilation system under the corresponding target operating condition is evaluated based on the sum of the corresponding first flow rate and the corresponding second flow rate when oil is present in at least one of the first oil collection bottle (58) and the second oil collection bottle (60).

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