An engine crankcase ventilation system

Abstract

The application provides an engine crankcase ventilation system, comprising a cylinder head, a cylinder head exhaust chamber of the cylinder head being communicated with a cylinder head exhaust chamber of the crankcase through a cylinder head internal oil gas return channel, a first crankcase internal oil gas return channel, a second crankcase internal oil gas return channel, a third crankcase internal oil gas return channel, a fourth crankcase internal oil gas return channel, an oil pan exhaust chamber of an oil pan and the cylinder head exhaust chamber; the cylinder head exhaust chamber is communicated with a transmission case exhaust chamber of a transmission case, a crankcase longitudinal separation channel and a flywheel housing upper horizontal oil gas channel at a free end; the cylinder head exhaust chamber is communicated with a flywheel housing exhaust chamber of a flywheel housing, a flywheel housing internal vertical oil gas channel, a flywheel housing upper horizontal oil gas channel, a breather and a flywheel housing oil return channel at a transmission end; and the breather oil return channel is communicated with the oil pan exhaust chamber. The engine crankcase ventilation system effectively reduces breather separation pressure, reduces oil consumption and air pollution.

Description

Technical Field

[0001] This invention belongs to the field of engine technology, and in particular relates to an engine crankcase ventilation system. Background Technology

[0002] The engine crankcase ventilation system is an effective measure to prevent excessive crankcase pressure, ensure crankcase sealing, reduce oil consumption, and improve emissions. With the increase in engine power density and increasingly stringent emission standards, higher requirements are placed on the crankcase ventilation system. While ensuring the reliability of the crankcase seal, it is necessary to more effectively reduce the oil content in the air-fuel mixture to ensure that emission performance meets the required standards.

[0003] In existing technology, engine crankcase ventilation systems typically rely on the pressure difference to draw the oil-air mixture accumulated in the crankcase upwards through vertical channels in the cylinder head into the valve chamber. After mixing with the gases within the valve chamber, the mixture directly enters the breather. This results in a high oil content in the valve chamber directly entering the breather. Furthermore, there is no dedicated oil-air separation channel before the mixture enters the breather, preventing timely and effective separation of engine oil, leading to increased engine oil consumption and worsened emissions.

[0004] For example, patent application CN200910251447.5 discloses a ventilation channel for a crankcase ventilation system, including a cylinder head ventilation channel and an oil-gas separator. A sealed pipe is used for gas transport between the cylinder head ventilation channel and the inlet of the oil-gas separator, avoiding direct contact between the oil-gas mixture and lubricating oil before the inlet of the oil-gas separator, effectively reducing the lubricating oil content in the oil-gas mixture. Although this patent uses a sealed pipe for gas-gas transport, the sealing effect is poor due to the significant vibration during engine operation. Furthermore, the sealed pipe is located inside the cylinder head cover, which increases the design difficulty of the cylinder head cover, making it harder to implement and resulting in a complex structure and manufacturing difficulties. It also increases the volume of the cylinder head cover, thus increasing the overall engine size. Summary of the Invention

[0005] In view of this, the present invention aims to provide an engine crankcase ventilation system to effectively reduce the oil content in the air-fuel mixture before the breather, reduce oil consumption, and improve emission performance.

[0006] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0007] An engine crankcase ventilation system includes a crankcase, a transmission case, an oil pan, a flywheel housing, a breather, and a cylinder head. The cylinder head exhaust chamber is connected to an oil-gas return channel within the cylinder head, a first crankcase oil-gas return channel, and a second crankcase oil-gas return channel. The second crankcase oil-gas return channel is connected to the oil pan exhaust chamber within the oil pan via a third crankcase oil-gas return channel and a fourth crankcase oil-gas return channel. The oil pan exhaust chamber is connected to the crankcase exhaust chamber within the crankcase. The crankcase exhaust chamber is located at a free end and... The transmission case exhaust chamber is connected to the transmission case exhaust chamber, which is connected to the crankcase longitudinal separation channel and the horizontal oil-gas channel on the flywheel housing; the crankcase exhaust chamber is connected to the flywheel housing exhaust chamber at the transmission end, which is connected to the flywheel housing exhaust chamber through the vertical oil-gas channel inside the flywheel housing and the horizontal oil-gas channel on the flywheel housing; the horizontal oil-gas channel on the flywheel housing is connected to the breather through the breather inlet channel; the lowest point of the horizontal oil-gas channel on the flywheel housing is connected to the flywheel housing return oil channel, and the breather return oil channel is connected to the oil pan exhaust chamber through the oil pan return oil channel.

[0008] Furthermore, the lower wall of the longitudinal separation channel of the crankcase has a downwardly inclined structure.

[0009] Furthermore, before the oil and gas enter the breather, it adopts an independent separation channel consisting of a longitudinal separation channel in the crankcase, a vertical oil and gas channel inside the flywheel housing, and a horizontal oil and gas channel on the flywheel housing.

[0010] Furthermore, an oil return channel is provided at the lowest point of the horizontal oil and gas channel on the flywheel housing, and an oil pan return channel is provided in the oil pan.

[0011] Compared with existing technologies, the engine crankcase ventilation system of the present invention has the following advantages:

[0012] (1) The engine crankcase ventilation system of the present invention leads the oil and gas in the cylinder head exhaust gas chamber to the oil pan exhaust gas chamber at the lowest point of the engine for the first separation of oil and gas. Then the oil and gas are separated together with the oil and gas in the crankcase through the oil and gas separation channels such as the crankcase and flywheel housing. All oil and gas use independent separation channels before entering the breather, which is conducive to the return of the separated oil and avoids the oil and gas containing a large amount of oil in the crankcase from directly entering the breather. This effectively reduces the content of lubricating oil in the oil-gas mixture before the breather, reduces the separation pressure of the breather, and reduces oil consumption and air pollution. Attached Figure Description

[0013] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0014] Figure 1 This is a top view of the engine described in an embodiment of the present invention;

[0015] Figure 2 for Figure 1 BB cross-sectional view;

[0016] Figure 3 for Figure 1 CC section view;

[0017] Figure 4 for Figure 1 FF sectional view;

[0018] Figure 5 for Figure 1 AA section view;

[0019] Figure 6 for Figure 1 DD sectional view;

[0020] Figure 7 for Figure 6 EE sectional view.

[0021] Explanation of reference numerals in the attached figures:

[0022] 1-Crankcase; 2-Transmission case; 3-Oil pan; 4-Flywheel housing; 5-Breaser; 6-Cylinder head; 7-Longitudinal separation channel of crankcase; 8-Vertical oil-gas passage inside flywheel housing; 9-Horizontal oil-gas passage on flywheel housing; 10-Breaser inlet passage; 11-Flywheel housing return oil passage; 12-Oil pan return oil passage; 13-Oil-gas return passage inside cylinder head; 14-Oil-gas return passage inside the first crankcase; 15-Oil-gas return passage inside the second crankcase; 16-Oil-gas return passage inside the third crankcase; 17-Oil-gas return passage inside the fourth crankcase; 100-Crankcase exhaust gas chamber; 200-Transmission case exhaust gas chamber; 300-Flywheel housing exhaust gas chamber; 400-Cylinder head exhaust gas chamber; 500-Oil pan exhaust gas chamber. Detailed Implementation

[0023] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0024] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention 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 the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0025] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" 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; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0027] An engine crankcase ventilation system, such as Figures 1 to 7As shown, the system includes a crankcase 1, a transmission case 2, an oil pan 3, a flywheel housing 4, a breather 5, and a cylinder head 6. The cylinder head exhaust chamber 400 of the cylinder head 6 is connected to the cylinder head oil-gas return channel 13, the first crankcase oil-gas return channel 14, and the second crankcase oil-gas return channel 15. The second crankcase oil-gas return channel 15 is connected to the oil pan exhaust chamber 500 of the oil pan 3 via the third crankcase oil-gas return channel 16 and the fourth crankcase oil-gas return channel 17. The oil pan exhaust chamber 500 is connected to the crankcase exhaust chamber 100 of the crankcase 1. The crankcase exhaust chamber 100 is connected to the transmission case 2 at its free end. The transmission case exhaust chamber 200 is connected to the crankcase longitudinal separation channel 7 and the flywheel housing horizontal oil-gas channel 9; the crankcase exhaust chamber 100 is connected to the flywheel housing exhaust chamber 300 of the flywheel housing 4 at the transmission end; the flywheel housing exhaust chamber 300 is connected to the flywheel housing horizontal oil-gas channel 9 through the vertical oil-gas channel 8 inside the flywheel housing; the flywheel housing horizontal oil-gas channel 9 is connected to the breather 5 through the breather inlet channel 10; the lowest point of the flywheel housing horizontal oil-gas channel 9 is connected to the flywheel housing return oil channel 11; the breather return oil channel 11 is connected to the oil pan exhaust chamber 500 through the oil pan return oil channel 12.

[0028] The engine crankcase ventilation system of this invention guides the oil and gas in the cylinder head exhaust chamber to the oil pan exhaust chamber at the lowest point of the engine for initial oil-gas separation. Then, the oil and gas, together with the oil and gas in the crankcase, are separated through oil-gas separation channels such as the crankcase and flywheel housing. All oil and gas use independent separation channels before entering the breather, which facilitates the return of separated oil and prevents oil and gas containing a large amount of oil in the crankcase from directly entering the breather. This effectively reduces the lubricating oil content in the oil-gas mixture before the breather, lowers the breather separation pressure, and reduces oil consumption and air pollution.

[0029] like Figure 2 , Figure 3 , Figure 4 As shown, the oil return from the lubrication valve train of each cylinder and the leakage gas generated from the valve guide will accumulate in the exhaust gas chamber 400 of each cylinder head. The oil and oil-gas mixture in the exhaust gas chamber 400 of each cylinder head will enter the horizontal oil-gas return channel 15 in the second crankcase through the oil-gas return channel 13 in the cylinder head and the oil-gas return channel 14 in the first crankcase, and then enter the exhaust gas chamber 500 in the oil pan through the oil-gas return channel 16 in the third crankcase and the oil-gas return channel 17 in the fourth crankcase. The separated oil will flow back to the oil pan reservoir.

[0030] like Figure 5 As shown, the oil pan exhaust chamber 500 and the crankcase exhaust chamber 100 are connected. The mixed oil and gas from the cylinder head enters the oil pan exhaust chamber 500 and then enters the crankcase exhaust chamber 100 to mix with the oil and gas in the crankcase.

[0031] like Figure 5 As shown, the crankcase exhaust chamber 100 is connected to the transmission case exhaust chamber 200 at its free end. A portion of the oil and gas in the crankcase enters the transmission case exhaust chamber 200 through the free end of the crankcase exhaust chamber 100, and then enters the horizontal oil and gas passage 9 on the flywheel housing through the longitudinal separation channel 7 of the crankcase. The lower wall of the inner cavity of the longitudinal separation channel 7 of the crankcase has a downward sloping structure. The oil separated through this channel flows back along the lower wall and then back to the oil pan reservoir through the transmission case exhaust chamber.

[0032] like Figure 5 As shown, the crankcase exhaust gas chamber 100 is connected to the flywheel housing exhaust gas chamber 300 at the transmission end. Another part of the oil and gas in the crankcase enters the flywheel housing exhaust gas chamber 300 through the transmission end of the crankcase exhaust gas chamber 100, and then enters the horizontal oil and gas channel 9 on the flywheel housing through the vertical oil and gas channel 8 inside the flywheel housing.

[0033] like Figure 6 , Figure 7 As shown, the oil and gas entering the horizontal oil and gas passage 9 on the flywheel housing enter the breather 5 through the inlet breather passage 10. A return oil passage 11 is provided at the lowest point of the horizontal oil and gas passage 9 on the flywheel housing (near the breather installation position), and an oil pan return oil passage 12 is provided in the oil pan to ensure that the oil separated from the horizontal oil and gas passage 9 on the flywheel housing and the oil separated from the breather 5 flows smoothly back into the oil pan.

[0034] In the ventilation system channel design, the oil and gas in the cylinder head exhaust chamber 400 first flow back to the oil pan exhaust chamber 500, which is located at the lowest point of the engine, to achieve the first separation of oil and gas. Then, it is further separated together with the oil and gas in the crankcase, so that the oil and gas in the cylinder head exhaust chamber 400 are fully separated before entering the breather, effectively reducing the separation pressure of the breather.

[0035] In terms of ventilation system channel settings, before the crankcase enters the breather, it adopts independent separation channels: the longitudinal separation channel 7 of the crankcase, the vertical oil-gas channel 8 inside the flywheel housing, and the horizontal oil-gas channel 9 on the flywheel housing. Oil and gas can be further separated in the independent channels, avoiding oil and gas containing a large amount of engine oil from directly entering the breather, effectively reducing the separation pressure of the breather and reducing engine oil consumption.

[0036] In terms of the ventilation system channel design, the lower wall of the longitudinal separation channel 7 of the crankcase is designed with a downward sloping structure, which facilitates the smooth return of the separated oil and effectively prevents the separated oil from being carried to the next channel by the oil and gas in the channel, thereby reducing the oil content in the oil-gas mixture.

[0037] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An engine crankcase ventilation system, characterized in that: The system includes a crankcase, transmission case, oil pan, flywheel housing, breather, and cylinder head. The cylinder head exhaust chamber is connected to the cylinder head oil-gas return channel, the first crankcase oil-gas return channel, and the second crankcase oil-gas return channel. The second crankcase oil-gas return channel is connected to the oil pan exhaust chamber via the third and fourth crankcase oil-gas return channels. The oil and gas in the cylinder head exhaust chamber enter the oil pan exhaust chamber through the aforementioned channels, achieving initial oil-gas separation. The separated oil flows back to the oil pan reservoir. The oil pan exhaust chamber is connected to the crankcase exhaust chamber of the crankcase. The mixed oil and gas in the oil pan exhaust chamber enter the crankcase exhaust chamber and mix with the oil and gas in the crankcase. The crankcase exhaust chamber is connected to the transmission case exhaust chamber at the free end, and the transmission case exhaust chamber is connected to the horizontal oil-gas passage on the flywheel housing through the longitudinal separation channel of the crankcase; the crankcase exhaust chamber is connected to the flywheel housing exhaust chamber at the transmission end, and the flywheel housing exhaust chamber is connected to the horizontal oil-gas passage on the flywheel housing through the vertical oil-gas passage inside the flywheel housing; the horizontal oil-gas passage on the flywheel housing is connected to the breather through the breather inlet channel; the lowest point of the horizontal oil-gas passage on the flywheel housing is connected to the flywheel housing return oil passage, and the breather return oil passage is connected to the oil pan exhaust chamber through the oil pan return oil passage; the oil separated from the horizontal oil-gas passage on the flywheel housing and the oil separated from the breather flow back to the oil pan through the corresponding return oil passage.

2. The engine crankcase ventilation system according to claim 1, characterized in that: The lower wall of the longitudinal separation channel of the crankcase has a downward sloping structure.

3. The engine crankcase ventilation system according to claim 1, characterized in that: Before the oil and gas enter the breather, independent separation channels are used, including a longitudinal separation channel in the crankcase, a vertical oil and gas channel inside the flywheel housing, and a horizontal oil and gas channel on the flywheel housing.

4. The engine crankcase ventilation system according to claim 1, characterized in that: An oil return channel is set at the lowest point of the horizontal oil and gas passage on the flywheel housing, and an oil return channel is set in the oil pan.

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