A vehicle engine ventilation system and control method

Abstract

This application discloses a vehicle engine ventilation system and control method, relating to the field of vehicle engine technology. The system includes: an engine cylinder head cover with a blow-by air intake port; an oil-gas separator with its intake end connected to the blow-by air intake port; a turbocharger connected to an air filter via an intake manifold; a three-way valve including an intake end, a first outlet end, and a second outlet end; and a controller for controlling the first outlet end to open and the second outlet end to close, while simultaneously shutting off the exhaust fan, to allow blow-by air to enter the turbocharger, when the engine is running; and for controlling the first outlet end to close and the second outlet end to open, while simultaneously controlling the exhaust fan to operate for a preset duration, when the engine is stopped and the engine coolant temperature exceeds a temperature threshold, to draw blow-by air to the EGP (Electronic Gas Boost System). The ventilation system and method of this application combine autonomous ventilation with closed-loop passive ventilation, which neither pollutes the atmosphere nor damages the engine lubricating oil.

Description

Technical Field

[0001] This application relates to the field of vehicle engine technology, specifically to a vehicle engine ventilation system and control method. Background Technology

[0002] Currently, with the rapid updates to heavy-duty vehicle emission regulations, the sixth stage emission standard has been released. Compared to the China V emission standard, the China VI standard imposes stricter requirements on the testing methods for heavy-duty vehicle engines. In the current China VI engine crankcase ventilation process, fresh air passes through an air filter and enters the turbocharger compressor, becoming high-temperature, high-pressure gas. This gas is then cooled by an intercooler before entering the engine combustion chamber, where it undergoes combustion with fuel. Most of the exhaust gas produced after combustion reaches the turbocharger turbine through the exhaust pipe, driving the turbine to perform work on the compressor. A small portion of the exhaust gas leaks into the engine crankcase through the gaps between the piston, piston rings, and cylinder bores.

[0003] In related technologies, for exhaust gas that leaks into the engine crankcase through the gap between the piston, piston rings and cylinder bore, open ventilation can be used, that is, the exhaust gas in the crankcase is directly discharged into the air; or, passive closed ventilation can be used, that is, the exhaust gas enters the intake pipe before the turbocharger compressor after passing through the oil-gas separator of the closed crankcase ventilation system.

[0004] However, the above-mentioned open ventilation process will pollute the atmosphere; in the above-mentioned passive closed ventilation process, when the engine is stopped, the gas in the crankcase ventilation system cannot be discharged, and the condensate and acidic substances after the gas condenses will damage the engine lubricating oil. Summary of the Invention

[0005] In view of the deficiencies in the prior art, the purpose of this application is to provide a vehicle engine ventilation system and control method to solve the problems of open ventilation causing air pollution and closed ventilation damaging engine lubricating oil in the related technologies.

[0006] The first aspect of this application provides a vehicle engine ventilation system, comprising: The engine cylinder head cover has a blow-by port on it; The oil-gas separator has its inlet end connected to the gas extraction port for cross-contamination. The turbocharger is connected to the air filter via the intake manifold; The three-way valve includes an inlet end, a first outlet end and a second outlet end. The inlet end is connected to the oil-gas separator, the first outlet end is connected to the main inlet pipe, and the second outlet end is connected to the exhaust fan. The controller is used to obtain the engine speed; When the engine speed is greater than a first threshold, the controller determines that the engine is running; when the engine speed is less than a second threshold, the controller determines that the engine is stopped; the first threshold is greater than the second threshold. When the engine is running, the first outlet is opened and the second outlet is closed, and the exhaust fan is turned off to allow blow-by gas to enter the turbocharger; it is also used to close the first outlet and open the second outlet when the engine is stopped and the engine coolant temperature is higher than the temperature threshold, and to turn on the exhaust fan for a preset time to draw blow-by gas to the after-treatment system EGP; when the exhaust fan reaches the preset time, the exhaust fan is turned off again. A balance line is used to connect the air filter to the engine cylinder block, with the air intake end of the air filter connected to the atmosphere; When the engine is running, the controller is also used to control the balance pipeline to shut off; when the engine is stopped and the engine coolant temperature is greater than the temperature threshold, the controller is also used to control the balance pipeline to connect.

[0007] In some embodiments, a shut-off valve is provided on the aforementioned balancing pipeline.

[0008] In some embodiments, the three-way valve is a two-position three-way valve, which is disposed on a curved pipe. The curved pipe includes a first pipe section connecting the oil-gas separator and the air inlet, a second pipe section connecting the air intake manifold and the first air outlet, and a third pipe section connecting the exhaust fan and the second air outlet.

[0009] In some embodiments, the above-described vehicle engine ventilation system further includes: Intercooler, which is used to cool down the high-pressure gas after passing through the turbocharger; The intake manifold connects the intercooler and the engine cylinder block.

[0010] In some embodiments, the above-described vehicle engine ventilation system further includes: The exhaust manifold connects the engine cylinder head and the turbocharger turbine. The exhaust tailpipe connects the turbocharger turbine and the EGP aftertreatment system.

[0011] A second aspect of this application provides a control method based on the aforementioned vehicle engine ventilation system, comprising the following steps: The controller determines the engine status; When the controller determines that the engine is running, it opens the first outlet of the three-way valve and closes the second outlet of the three-way valve, while simultaneously turning off the exhaust fan to allow blow-by gas to enter the turbocharger. When the controller determines that the engine is stopped and the engine coolant temperature is higher than the temperature threshold, it controls the first exhaust end to close and the second exhaust end to open. At the same time, it controls the exhaust fan to open for a preset time to draw out the blow-by air to the EGP after-treatment system.

[0012] In some embodiments, before the controller determines the engine status, it further includes: Obtain the engine speed, and a first threshold and a second threshold for the engine speed; When the engine speed is greater than the first threshold, the controller determines that the engine is running. When the engine speed is less than the second threshold, the controller determines that the engine is in a stopped state; the first threshold is greater than the second threshold.

[0013] In some embodiments, the system further includes a balance line for connecting the air filter to the engine cylinder block, the balance line being provided with a shut-off valve; When the controller determines that the engine is running, the controller controls the above-mentioned shut-off valve to close, thereby shutting off the above-mentioned balance pipeline. When the controller determines that the engine is stopped and the engine coolant temperature is higher than the temperature threshold, the controller controls the above-mentioned shut-off valve to open so as to connect the above-mentioned balance pipeline.

[0014] The beneficial effects of the technical solution provided in this application include: The vehicle engine ventilation system and control method of this application utilize a blow-by gas intake port on the cylinder head cover to facilitate the separation of blow-by gas through an oil-gas separator. When the engine is running, the controller controls the opening of the first outlet of the three-way valve and the closing of the second outlet, while simultaneously shutting off the exhaust fan, so that the outlet of the oil-gas separator is connected to the intake manifold. At this time, under the negative pressure of the intake manifold, the blow-by gas separated by oil-gas is mixed with fresh air after air filtering, and after being pressurized by the turbocharger, it enters the engine cylinder for combustion and power generation. When the engine is stopped and the engine coolant temperature is higher than the temperature threshold, the controller also controls the closing of the first outlet of the three-way valve and the opening of the second outlet, while simultaneously controlling the exhaust fan to be turned on for a preset duration. At this time, the outlet of the oil-gas separator is connected to the exhaust fan, so that the blow-by gas after oil-gas separation is drawn to the EGP for after-treatment. Because it uses a combination of autonomous ventilation and closed passive ventilation, the crankcase blow-by gas is introduced into the cylinder for combustion by means of the pressure difference between the crankcase and the intake air during closed passive ventilation. When the engine is stopped and the water temperature is higher than the temperature threshold, autonomous ventilation is used to introduce the blow-by gas in the crankcase into the aftertreatment device for purification before being discharged into the atmosphere. Therefore, it will not pollute the atmosphere or damage the engine lubricating oil. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a system schematic diagram of the engine operating state in an embodiment of this application; Figure 2 This is a schematic diagram of the system in the engine shutdown state in an embodiment of this application; Figure 3 This is a flowchart of the control method in the embodiments of this application.

[0017] Figure label: 1. Oil-gas separator; 2. Turbocharger; 3. Intake manifold; 4. Air filter; 5. Three-way valve; 6. Exhaust fan; 7. Controller; 8. EGP; 9. Balance line; 10. Engine cylinder block; 11. Shut-off valve; 12. Turning pipe; 13. Intercooler; 14. Intake manifold; 15. Exhaust manifold; 16. Exhaust tailpipe. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0019] This application provides a vehicle engine ventilation system that solves the problems in related technologies where open ventilation causes air pollution and closed ventilation damages engine lubricating oil.

[0020] like Figure 1 and Figure 2 As shown, the vehicle engine ventilation system of this embodiment includes an engine cylinder head cover, an oil-gas separator 1, a turbocharger 2, a three-way valve 5, and a controller 7.

[0021] The aforementioned engine cylinder head cover has a blow-by port to facilitate the discharge of blow-by gas that has entered the crankcase along the gap between the piston and the cylinder block, thereby ensuring pressure balance between the crankcase and the outside environment.

[0022] The air inlet of the oil-gas separator 1 is connected to the blow-by air intake port. In this embodiment, a curved exhaust pipe is connected between the oil-gas separator 1 and the cylinder head cover to facilitate the connection between the blow-by air intake port and the oil-gas separator 1 through the curved exhaust pipe.

[0023] The aforementioned turbocharger 2 is connected to the air filter 4 via the intake manifold 3. In this embodiment, fresh air is filtered by the air filter 4 and then enters the compressor of the turbocharger 2 through the intake manifold 3, becoming high-temperature and high-pressure gas.

[0024] The aforementioned three-way valve 5 includes an inlet end, a first outlet end, and a second outlet end. The inlet end is connected to the oil-gas separator 1, the first outlet end is connected to the intake manifold 3, and the second outlet end is connected to the exhaust fan 6. When the first outlet end of the three-way valve 5 is open and the second outlet end is closed, the outlet end of the oil-gas separator 1 is connected to the intake manifold 3; when the second outlet end of the three-way valve 5 is open and the first outlet end is closed, the outlet end of the oil-gas separator 1 is connected to the exhaust fan 6.

[0025] The controller 7 is used to control the first exhaust end to open and the second exhaust end to close when the engine is running, and at the same time to turn off the exhaust fan 6 so that blow-by gas enters the turbocharger 2; the controller 7 is also used to control the first exhaust end to close and the second exhaust end to open when the engine is stopped and the engine coolant temperature is greater than the temperature threshold, and at the same time to control the exhaust fan 6 to open for a preset time so as to draw blow-by gas to the after-processor EGP (Exhaust Gas Processor) 8.

[0026] Optionally, the controller 7 is also used to turn off the exhaust fan 6 again when the exhaust fan 6 has been turned on for the preset duration.

[0027] The vehicle engine ventilation system of this embodiment has a blow-by air intake port on the cylinder head cover to facilitate the separation of blow-by air through an oil-gas separator. When the engine is running, the controller controls the first outlet of the three-way valve to open and the second outlet to close, while simultaneously shutting off the exhaust fan, so that the outlet of the oil-gas separator is connected to the intake manifold. At this time, under the negative pressure of the intake manifold, the blow-by air that has undergone oil-gas separation mixes with the fresh air after air filtering, and after being pressurized by the turbocharger, it enters the engine cylinder for combustion to do power. When the engine is stopped and the engine coolant temperature is higher than the temperature threshold, the controller also controls the first outlet of the three-way valve to close and the second outlet to open, while simultaneously controlling the exhaust fan to be turned on for a preset time. At this time, the outlet of the oil-gas separator is connected to the exhaust fan, so that the blow-by air after oil-gas separation is drawn to the EGP for post-treatment steps through the exhaust fan. Because it uses a combination of autonomous ventilation and closed passive ventilation, the crankcase blow-by gas is introduced into the cylinder for combustion by means of the pressure difference between the crankcase and the intake air during closed passive ventilation. When the engine is stopped and the water temperature is higher than the temperature threshold, autonomous ventilation is used to introduce the blow-by gas in the crankcase into the after-treatment system for purification before being discharged into the atmosphere. Therefore, it will not pollute the atmosphere or damage the engine lubricating oil.

[0028] Preferably, the controller 7 is an ECU (Electronic Control Unit). The ECU consists of a microprocessor, memory, input / output interface, analog-to-digital converter, and large-scale integrated circuits for shaping and driving.

[0029] In this embodiment, the vehicle engine ventilation system further includes an engine cylinder block and an engine cylinder head.

[0030] Based on the above embodiments, in this embodiment, the vehicle engine ventilation system further includes a balance pipe 9, which is used to connect the air filter 4 to the engine cylinder block 10, and the air intake end of the air filter 4 is connected to the atmosphere.

[0031] Alternatively, in other embodiments, the aforementioned balance pipe 9 can also be used to connect the aforementioned air filter 4 to the engine cylinder head.

[0032] In this embodiment, when the engine is running, the controller 7 is also used to control the balance pipeline 9 to shut off, so as to disconnect the air filter 4 from the engine cylinder block 10.

[0033] When the engine is stopped and the engine coolant temperature is higher than the temperature threshold, the controller 7 is also used to control the connection of the balance pipe 9 to connect the air filter 4 and the engine cylinder block 10.

[0034] Furthermore, the aforementioned balance pipeline 9 is equipped with a shut-off valve 11. When the engine is running, the aforementioned controller 7 is used to close the shut-off valve 11 to disconnect the balance pipeline 9; when the engine is stopped and the engine coolant temperature is greater than the temperature threshold, the aforementioned controller 7 is used to open the shut-off valve 11 to connect the aforementioned balance pipeline 9.

[0035] Optionally, when the engine is stopped and the engine coolant temperature is greater than the temperature threshold, the controller 7 can also be used to open the shut-off valve 11 for the preset duration to connect the balance pipeline 9; and when the preset duration is reached, close the shut-off valve 11 again to disconnect the balance pipeline 9.

[0036] Based on the above embodiments, in this embodiment, the three-way valve 5 is a two-position three-way valve, which is installed on the curved pipe 12. The curved pipe 12 includes a first pipe section, a second pipe section, and a third pipe section. The first pipe section is used to connect the oil-gas separator 1 to the air inlet of the two-position three-way valve, the second pipe section is used to connect the main air intake pipe 3 to the first air outlet of the two-position three-way valve, and the third pipe section is used to connect the exhaust fan 6 to the second air outlet of the two-position three-way valve.

[0037] Preferably, the system further includes an intercooler 13 and an intake manifold 14. The intercooler 13 is used to cool down the high-pressure gas passing through the turbocharger 2; the intake manifold 14 is used to connect the intercooler 13 and the engine cylinder block 10.

[0038] Alternatively, in other embodiments, the intake manifold 14 can also be used to connect the air filter 4 to the engine cylinder head.

[0039] Furthermore, the aforementioned system also includes an exhaust manifold 15 and an exhaust tailpipe 16. The exhaust manifold 15 connects the engine cylinder head and the turbocharger 2 turbine; the exhaust tailpipe 16 connects the turbocharger 2 turbine and the EGP8.

[0040] Most of the exhaust gas produced after engine combustion passes through exhaust manifold 15 to the turbine of turbocharger 2 to drive the turbine to rotate and do work on the compressor. Finally, it passes through exhaust tailpipe 16 to enter EGP8 for after-treatment before being discharged into the atmosphere.

[0041] Based on the above embodiments, in this embodiment, the controller 7 is also used to acquire the engine speed.

[0042] When the engine speed is greater than the first threshold, the controller 7 determines that the engine is running; when the engine speed is less than the second threshold, the controller 7 determines that the engine is stopped; the first threshold is greater than the second threshold.

[0043] Preferably, the first threshold is 100 rpm; the second threshold is 10 rpm.

[0044] In this embodiment, the engine's starting speed is generally between 150-200 rpm. Therefore, when the engine speed is greater than 100 rpm, it can be determined that the engine is running, and the blow-by gas generated at this time can be introduced into the cylinder for combustion. Furthermore, due to the zero-drift phenomenon of the sensor, even when the engine is not running, there may still be a reading. To avoid misjudging the engine status, a second threshold is set: when the engine speed is less than 10 rpm, the engine is determined to be in a stopped state. At this time, the blow-by gas cannot enter the engine for combustion and can only enter the EGP8 for purification through the exhaust fan 6.

[0045] Furthermore, when the controller 7 determines that the engine is in a stopped state, the controller 7 is also used to obtain the engine coolant temperature.

[0046] Preferably, the temperature threshold for the engine coolant temperature can be set according to the actual vehicle model.

[0047] In this embodiment, the temperature threshold of the engine coolant temperature can be set to 90°C.

[0048] In other embodiments, the temperature threshold for the engine coolant temperature can also be set to 85°C.

[0049] Preferably, the preset duration is 60 seconds. That is, when the controller 7 determines that the engine speed is greater than 100 rpm and the engine coolant temperature is greater than 90°C, the controller 7 controls the second outlet of the two-position three-way valve to open, the shut-off valve to open, and the exhaust fan to be energized. All actions are performed for 60 seconds to draw the blow-by gas to the EGP8 for purification. Subsequently, the exhaust fan can be turned off, the shut-off valve can be disconnected, and the second outlet can be closed.

[0050] In other embodiments, different preset activation durations can be set for different engine coolant temperatures. For higher engine coolant temperatures, a longer preset activation duration can be set. Optionally, when the engine coolant temperature is greater than 85°C and less than or equal to 90°C, the corresponding preset duration is 45 seconds; when the engine coolant temperature is greater than 90°C and less than or equal to 95°C, the corresponding preset duration is 60 seconds; and when the engine coolant temperature is greater than 95°C, the corresponding preset duration is 100 seconds.

[0051] In this embodiment, the blow-by gas intake is located on the engine cylinder head cover. After the blow-by gas comes out, it first enters the oil-gas separator for oil-gas separation. The separated gas can be determined according to the engine operating status to either enter the intake manifold 3 to participate in combustion, or enter the EGP8 for purification and then be discharged from the engine. At this time, the ECU determines whether to use autonomous or passive ventilation based on the engine operating status, which is controlled by the actuator two-position three-way valve.

[0052] like Figure 1 As shown, when the engine speed is greater than 100 rpm, the ECU determines that the engine is running. At this time, the ECU issues a command: the two-position three-way valve is in position 1, and the shut-off valve is in the closed state; at this time, the exhaust fan is also in the closed state. The two-position three-way valve is connected to the intake manifold. Under the action of the negative pressure of the intake manifold, the blow-by air enters the intake manifold through the two-position three-way valve, mixes with the fresh air after air filter, and enters the engine cylinder for combustion and power after being pressurized by the turbocharger.

[0053] like Figure 2 As shown, when the engine speed is less than 10 rpm and the engine coolant temperature is greater than 90℃, the ECU issues a command: the two-position three-way valve is in position 2, the shut-off valve is open, and the exhaust fan is energized. All actions are performed for 60 seconds. At this time, the three-way valve, exhaust fan, and EGP are connected. Under the suction of the exhaust fan, the blow-by gas enters the EGP through the two-position three-way valve and the exhaust fan, is purified, and then discharged into the atmosphere. In order to maintain the pressure balance inside and outside the engine, fresh air will enter the engine through the air filter and shut-off valve due to the pressure difference.

[0054] like Figure 3As shown, this application also provides an embodiment of a control method based on the above-described vehicle engine ventilation system, the control method specifically including the following steps: S1. Controller 7 determines the engine status. At this time, controller 7 can obtain the engine speed and engine coolant temperature to determine the status.

[0055] S2. When the controller 7 determines that the engine is running, the controller 7 controls the first outlet of the three-way valve 5 to open and the second outlet of the three-way valve 5 to close, and at the same time shuts off the exhaust fan 6 so that blow-by gas enters the turbocharger 2. S3. When the controller 7 determines that the engine is in a stopped state and the engine coolant temperature is greater than the temperature threshold, the controller 7 controls the first exhaust end to close and the second exhaust end to open, and at the same time controls the exhaust fan 6 to open for a preset time to draw in blow-by air to EGP8.

[0056] Furthermore, when the exhaust fan 6 has been on for the preset duration, the controller 7 turns off the exhaust fan 6 again.

[0057] The order of steps S2 and S3 can be reversed.

[0058] Preferably, when the controller 7 determines that the engine is in a stopped state and the engine water temperature is greater than the temperature threshold, the controller 7 controls the second air outlet to open for a preset time, and then the second air outlet can be closed again.

[0059] In this embodiment, when the engine is running, the controller opens the first outlet of the three-way valve and closes the second outlet, while simultaneously shutting off the exhaust fan. This connects the outlet of the oil-gas separator to the intake manifold. Under the negative pressure of the intake manifold, the blow-by gas separated by the oil-gas separator mixes with the fresh air filtered by the air filter, and after being pressurized by the turbocharger, it enters the engine cylinder for combustion. When the engine is off and the engine coolant temperature exceeds a certain threshold, the controller closes the first outlet of the three-way valve and opens the second outlet, while simultaneously controlling the exhaust fan to operate for a preset duration. In this case, the outlet of the oil-gas separator connects to the exhaust fan, allowing the blow-by gas separated by the oil-gas separator to be drawn to the EGP for post-treatment. This combination of autonomous ventilation and closed passive ventilation avoids both air pollution and damage to the engine lubricating oil.

[0060] Furthermore, in step S1 above, before the controller 7 determines the engine status, the following steps are also included: First, obtain the engine speed, and the first and second thresholds for the engine speed.

[0061] Then, when the engine speed is greater than the first threshold, the controller 7 determines that the engine is running; when the engine speed is less than the second threshold, the controller 7 determines that the engine is stopped; the first threshold is greater than the second threshold.

[0062] Furthermore, when the controller 7 determines that the engine is in a stopped state, the following steps are also included: Obtain the current engine coolant temperature and compare it with a temperature threshold.

[0063] If the engine coolant temperature is less than or equal to the temperature threshold, there is no need to turn on the exhaust fan 6 to suck in blow-by gases.

[0064] Based on the above embodiments, in this embodiment, the system further includes a balance pipe 9 for connecting the air filter 4 and the engine cylinder block 10, and the balance pipe 9 is provided with a shut-off valve 11.

[0065] When the controller 7 determines that the engine is running, the controller 7 controls the shut-off valve 11 to close, thereby shutting off the balance line 9, so as to prevent fresh air filtered by the air filter 4 from entering the engine directly without passing through the supercharger 2.

[0066] When the controller 7 determines that the engine is in a stopped state and the engine water temperature is greater than the temperature threshold, the controller 7 controls the above-mentioned shut-off valve 11 to open so as to connect the above-mentioned balance pipeline 9.

[0067] Optionally, when the engine is stopped and the engine coolant temperature is greater than the temperature threshold, the controller 7 can also control the shut-off valve 11 to open for the preset duration, and close the shut-off valve 11 again when the preset duration is reached, so as to disconnect the balance pipeline 9.

[0068] Based on the above embodiments, this embodiment further includes the following steps before determining the engine status: First, a first threshold and a second threshold for pre-stored engine speed.

[0069] Then, the temperature threshold of the engine coolant temperature and the preset duration of the opening time of the exhaust fan 6 and the shut-off valve 11 are obtained.

[0070] The engine coolant temperature threshold and the preset duration for opening the exhaust fan 6 and shut-off valve 11 can be set according to the specific vehicle model. Furthermore, the system also includes an intercooler 13 and an intake manifold 14. The intercooler 13 cools down the high-pressure gas passing through the turbocharger 2 before it enters the engine cylinder block 10 through the intake manifold 14.

[0071] In this embodiment, the system further includes an exhaust manifold 15 and an exhaust tailpipe 16. The exhaust manifold 15 connects the engine cylinder head and the turbocharger 2 turbine; the exhaust tailpipe 16 connects the turbocharger 2 turbine and the EGP8.

[0072] In this embodiment, autonomous ventilation uses an electronic exhaust fan to draw out the blow-by air in the crankcase and introduces it into the EGP for purification through a pipeline. At the same time, fresh air is introduced into the crankcase to maintain the pressure balance inside and outside the machine.

[0073] The control method of this embodiment is applicable to the above-mentioned ventilation systems. It adopts a combination of autonomous ventilation and closed passive ventilation. In closed passive ventilation, the blow-by gas in the crankcase is introduced into the cylinder for combustion by means of the pressure difference between the crankcase and the intake air. When the engine is stopped and the water temperature is higher than the temperature threshold, autonomous ventilation is adopted to introduce the blow-by gas in the crankcase into the after-processor for purification and then discharge it into the atmosphere. Therefore, it will not pollute the atmosphere or damage the engine lubricating oil.

[0074] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0075] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0076] The above are merely specific embodiments of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A vehicle engine ventilation system characterized by, It includes: The engine cylinder head cover has a blow-by port on it; The oil-gas separator (1) has its inlet end connected to the gas extraction port; The turbocharger (2) is connected to the air filter (4) through the intake manifold (3); The three-way valve (5) includes an inlet end, a first outlet end and a second outlet end. The inlet end is connected to the oil-gas separator (1), the first outlet end is connected to the main inlet pipe (3), and the second outlet end is connected to the exhaust fan (6). Controller (7), which is used to obtain engine speed; When the engine speed is greater than the first threshold, the controller (7) determines that the engine is running; when the engine speed is less than the second threshold, the controller (7) determines that the engine is stopped; the first threshold is greater than the second threshold. When the engine is running, the first outlet is opened and the second outlet is closed, and the exhaust fan (6) is turned off at the same time to allow blow-by gas to enter the turbocharger (2); it is also used to close the first outlet and open the second outlet when the engine is stopped and the engine water temperature is greater than the temperature threshold, and to turn on the exhaust fan (6) for a preset time to draw blow-by gas to the after-treatment EGP (8), and turn off the exhaust fan (6) again when the preset time is reached. Balance pipe (9) is used to connect the air filter (4) to the engine cylinder block (10), and the air intake end of the air filter (4) is connected to the atmosphere; When the engine is running, the controller (7) is also used to control the balance pipe (9) to shut off; when the engine is stopped and the engine water temperature is greater than the temperature threshold, the controller (7) is also used to control the balance pipe (9) to connect.

2. The vehicle engine ventilation system as described in claim 1, characterized in that: The balance pipeline (9) is equipped with a shut-off valve (11).

3. The vehicle engine ventilation system as described in claim 1, characterized in that: The three-way valve (5) is a two-position three-way valve, which is installed on the curved pipe (12). The curved pipe (12) includes a first pipe section connecting the oil-gas separator (1) and the air inlet, a second pipe section connecting the main air inlet pipe (3) and the first air outlet, and a third pipe section connecting the exhaust fan (6) and the second air outlet.

4. The vehicle engine ventilation system as described in claim 1, characterized in that, The system also includes: Intercooler (13), which is used to cool down the high-pressure gas passing through the booster (2); The intake manifold (14) is used to connect the intercooler (13) and the engine cylinder block (10).

5. The vehicle engine ventilation system as described in claim 1, characterized in that, The system also includes: Exhaust manifold (15) connects the engine cylinder head and the turbocharger (2) turbine; The exhaust tailpipe (16) connects to the turbocharger (2) turbine and EGP (8).

6. A control method based on the vehicle engine ventilation system of claim 1, characterized in that, It includes the following steps: The controller (7) determines the engine status; When the controller (7) determines that the engine is running, it controls the first outlet of the three-way valve (5) to open and the second outlet of the three-way valve (5) to close, and at the same time shuts off the exhaust fan (6) so that blow-by gas enters the turbocharger (2). When the controller (7) determines that the engine is in a stopped state and the engine water temperature is greater than the temperature threshold, it controls the first air outlet to close and the second air outlet to open, and at the same time controls the exhaust fan (6) to open for a preset time to draw out the blow-by air to the after-processor EGP (8).

7. The control method as described in claim 6, characterized in that, Before the controller (7) determines the engine status, it also includes: Obtain the engine speed, and a first threshold and a second threshold for the engine speed; When the engine speed is greater than the first threshold, the controller (7) determines that the engine is in operation. When the engine speed is less than the second threshold, the controller (7) determines that the engine is in a stopped state; the first threshold is greater than the second threshold.

8. The control method as described in claim 7, characterized in that, The system also includes a balance line (9) for connecting the air filter (4) and the engine cylinder block (10), and the balance line (9) is provided with a shut-off valve (11). When the controller (7) determines that the engine is running, the controller (7) controls the shut-off valve (11) to close, thereby shutting off the balance pipeline (9). When the controller (7) determines that the engine is in a stopped state and the engine water temperature is greater than the temperature threshold, the controller (7) controls the shut-off valve (11) to open so as to connect the balance pipeline (9).

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