A crankcase ventilation system for an opposed engine

Abstract

The application discloses a crankcase ventilation system for a horizontally-opposed engine, comprising an oil-gas separator, a timing cover, a crankcase pressure regulating valve and an intake manifold pressure stabilizing chamber. The oil-gas separator is fixedly connected with the timing cover, and three independent chambers, i.e., a left chamber, a right chamber and a lower chamber, are formed between the oil-gas separator and the timing cover. The left chamber is communicated with the intake manifold pressure stabilizing chamber through the crankcase pressure regulating valve, the right chamber is communicated with a clean side of an air filter, and the lower chamber is an oil return chamber and is communicated with an oil return passage inside an engine cylinder body. The oil-gas separator, the timing cover and the intake manifold pressure stabilizing chamber are integrated by the application, the structure is compact, the sealing is reliable, and the oil-gas separation efficiency is high. The double-path ventilation design can stably control the crankcase pressure under different working conditions. The oil return passage is built-in, and the safety is reliable. The application is suitable for small-displacement horizontally-opposed engines in the fields of automobile range extenders and low-altitude aircrafts.

Description

Technical Field

[0001] This invention relates to the field of engine equipment, and more specifically to a crankcase ventilation system for a horizontally opposed engine. Background Technology

[0002] A horizontally opposed engine is an internal combustion engine with cylinders arranged horizontally opposite each other. It is characterized by its small size, compact structure, and light weight, and can be widely used in automotive range extenders, low-altitude aircraft, and other fields. The crankcase ventilation system is an important component of the engine. Its function is to extract blow-by gases (containing oil vapor and combustion exhaust gases) from the crankcase and separate them. The separated gases are then introduced into the intake system to participate in combustion, while the separated engine oil flows back to the oil pan for recycling.

[0003] In the prior art, crankcase ventilation systems generally have the following defects: (1) Bulky structure with many parts. The oil-gas separator, intake manifold, PCV valve and other components of the existing crankcase ventilation system are mostly set up independently and connected by external pipelines, resulting in a bulky overall structure, too many external interfaces and complicated assembly. (2) Poor sealing reliability. The existing technology mostly uses sealing rings and bolt connections for sealing, resulting in many sealing points, a high risk of leakage, and bolt connections require a large installation space, which is not conducive to the miniaturization design of the engine. (3) Low oil-gas separation efficiency. The existing oil-gas separators mostly use simple baffle structures or cyclone separation structures, which have limited separation effect on fine oil droplets, especially when the separation effect is worse at low blow-by volume. (4) Single crankcase pressure regulation method. The existing technology mostly only regulates the crankcase pressure through the PCV valve, which has limited pressure regulation effect under different engine operating conditions and makes it difficult to ensure the stability of the crankcase pressure. (5) The return oil line is externally located, which has low reliability. Most of the existing return oil lines are externally located, extending from the oil-gas separator to the oil pan. They are easily affected by the external environment and may experience blockages or breakages. They also occupy external space of the engine.

[0004] Currently, Chinese Patent CN105019980B discloses an oil-gas separator in a crankcase forced ventilation system of an engine, comprising an oil-gas separator pipe in fluid communication with an intake pipe and an oil reservoir; and an input pipe including an input pipe hole disposed at an angle between 80 degrees and 100 degrees relative to the oil-gas separator pipe, the input pipe hole opening into the separator pipe at a position between the outlet and the inlet of the separator pipe.

[0005] While the oil-gas separator in the crankcase forced ventilation system of this engine improves the compactness of the PCV system, increases the amount of oil removed from the crankcase gases, reduces losses in the oil-gas separator, extends the engine's operating time, and reduces engine emissions, it does not solve the aforementioned problems.

[0006] Therefore, there is an urgent need to develop a crankcase ventilation system for horizontally opposed engines that is compact, highly integrated, reliably sealed, and has high oil-gas separation efficiency. Summary of the Invention

[0007] The purpose of this invention is to provide a crankcase ventilation system for a horizontally opposed engine to solve the technical problems in the prior art, such as bulky structure, poor sealing reliability, low oil-gas separation efficiency, single pressure regulation, and external oil return pipeline.

[0008] The above-mentioned technical objective of the present invention is achieved through the following technical solution: A crankcase ventilation system for a horizontally opposed engine, characterized in that it includes an oil-gas separator, a timing cover, a crankcase pressure regulating valve, and an intake manifold pressure regulating chamber; the oil-gas separator is fixedly connected to the timing cover, forming three independent chambers: a left chamber, a right chamber, and a lower chamber; the oil-gas separator is provided with a blow-by inlet, which is connected to the left and right chambers respectively; the left chamber is provided with a first oil-gas separation device, and the left chamber is connected to the intake manifold pressure regulating chamber through the crankcase pressure regulating valve; the right chamber is provided with an outlet and is connected to the clean side of the air filter; the lower chamber is an oil return chamber, which is connected to the left and right chambers respectively through an oil return hole, and the lower chamber is also connected to the engine block through an oil return channel.

[0009] The above technical solution adopts a three-chamber integrated design, which fixes the oil-gas separator to the timing cover to form three independent chambers: the left chamber, the right chamber, and the lower chamber. Combined with the dual-path ventilation structure and the built-in oil return channel, the crankcase ventilation system is highly integrated, eliminating a large number of external pipes and connection interfaces, and significantly reducing the system size and weight. It is particularly suitable for the compact space requirements of horizontally opposed engines.

[0010] Further configuration: The oil-gas separator and the intake manifold pressure regulating chamber are fixedly connected by welding to form a sub-assembly, which is then fixedly connected to the timing cover.

[0011] The above technical solution involves welding the oil-gas separator and the intake manifold pressure regulating chamber to form a sub-assembly, which is then connected to the timing cover. This eliminates the need for sealing rings and bolts, resulting in fewer sealing points, more reliable sealing, shorter assembly time, and lower manufacturing costs.

[0012] Further configuration: The crankcase pressure regulating valve is located in the internal space between the oil-gas separator and the intake manifold pressure regulating chamber.

[0013] The above technical solution involves placing the crankcase pressure regulating valve in the internal space between the oil-gas separator and the intake manifold pressure regulating chamber, thus avoiding loosening or damage caused by external environmental factors (high temperature, low temperature, high humidity, and human factors), and improving the safety and reliability of the system.

[0014] Further configuration: The first oil-gas separation device includes a perforated plate for accelerating the airflow and a nail plate for impacting and separating oil droplets.

[0015] Through the above technical solution: the first oil-gas separation device adopts an impact-type separation structure with a perforated plate and a nail plate. When the gas flows through the perforated plate, it is accelerated, and the fine oil droplets are captured and separated by high-speed impact on the nail plate. The oil-gas separation efficiency is high, especially the separation effect of fine oil droplets is significant.

[0016] Further configuration: The air outlet of the right chamber is a throttling orifice.

[0017] By adopting the above technical solution, the air outlet of the right chamber is designed with a throttling orifice, which can limit the flow of blow-by air from the crankcase and keep the crankcase pressure stable so as not to be too low.

[0018] Further configuration: The oil-gas separator and the timing cover are connected by welding or adhesive bonding.

[0019] By adopting the above technical solution, the oil-gas separator and the timing cover are connected by welding or adhesive bonding, eliminating the need for sealing rings and bolts, reducing sealing points, lowering the risk of leakage, and improving sealing reliability.

[0020] Further configuration: The oil-gas separator body and the engine cylinder block are sealed with end seals using sealing rings.

[0021] By adopting the above technical solution, the oil-gas separator body and the engine cylinder block are sealed with end seals using sealing rings, which ensures the sealing performance of the connection and prevents gas leakage or oil leakage.

[0022] Further configuration: The intake manifold pressure regulating chamber is also connected to the left intake manifold and the right intake manifold respectively.

[0023] By adopting the above technical solution, the intake manifold pressure regulating chamber is connected to the left intake manifold and the right intake manifold respectively, which is adapted to the intake requirements of the left and right cylinders of the horizontally opposed engine and ensures that the intake of each cylinder is uniform.

[0024] In summary, this application has the following beneficial effects: By organically combining three-chamber integrated design, dual-path ventilation structure, built-in oil return channel, welded connection, built-in PCV valve, and impact-type oil-gas separation, it achieves multiple technical effects such as compact structure, high integration, reliable sealing, high oil-gas separation efficiency, stable pressure regulation, and safety and reliability. It effectively solves the technical problems of bulky structure, poor sealing reliability, low oil-gas separation efficiency, single pressure regulation, and external oil return pipeline in existing technologies. It also has the following beneficial effects: (1) The structure is compact and highly integrated, eliminating a large number of external pipes and connection interfaces, greatly reducing the system volume and weight, and is particularly suitable for the compact space requirements of horizontally opposed engines.

[0025] (2) Reliable sealing and easy assembly. The oil-gas separator is connected to the intake manifold pressure regulating chamber by welding, and the oil-gas separator is also connected to the timing cover by welding or adhesive bonding. This eliminates the need for sealing rings and bolts, resulting in fewer sealing points, higher reliability, shorter assembly time, and reduced manufacturing costs.

[0026] (3) High oil-gas separation efficiency. The impact separation structure with perforated plate and nail plate is adopted. When the gas flows through the perforated plate, it is accelerated. The fine oil droplets are captured and separated by high-speed impact on the nail plate. The separation efficiency is high, especially the separation effect of fine oil droplets is significant.

[0027] (4) The crankcase pressure regulation method is diverse and the stability is good. The system has two ventilation paths: one path is connected to the intake manifold pressure regulating chamber through the crankcase pressure regulating valve, and the other path is connected to the clean side of the air filter through the throttling orifice. The two paths work together to stably control the crankcase pressure under different engine operating conditions.

[0028] (5) Built-in oil return channel, safe and reliable. The oil return channel is completely set inside the oil-gas separator, timing cover and engine block, avoiding the influence of the external environment on the oil return channel, eliminating the risk of oil return pipe blockage and breakage, and improving system reliability.

[0029] (6) The crankcase pressure regulating valve is built-in, ensuring high safety. The crankcase pressure regulating valve is located in the internal space formed by welding the oil-gas separator and the intake manifold pressure regulating chamber, avoiding loosening or damage caused by external environment (high temperature, low temperature, high humidity, human factors), making it safe and reliable. Attached Figure Description

[0030] The invention will be further described below with reference to the accompanying drawings.

[0031] Figure 1 This is a schematic diagram of the overall structure of the crankcase ventilation system for a horizontally opposed engine; Figure 2This is a side view of the crankcase ventilation system for a horizontally opposed engine; Figure 3 This is a cross-sectional structural diagram of the crankcase ventilation system for a horizontally opposed engine.

[0032] In the diagram, 1. Oil-gas separator; 2. Timing cover; 3. Crankcase pressure regulating valve; 4. Intake manifold pressure regulating chamber; 5. Left side chamber; 6. Right side chamber; 7. Lower side chamber; 8. Blow-through inlet; 9. First oil-gas separator; 10. Oil return hole connection; 11. Oil return channel; 12. Perforated plate; 13. Nail plate; 14. Throttling orifice; 15. End of sealing ring; 16. Left intake manifold; 17. Right intake manifold. Detailed Implementation

[0033] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0034] The technical solution adopted in this invention is: a crankcase ventilation system for a horizontally opposed engine, such as... Figure 1 , Figure 2 and Figure 3 As shown, it is suitable for small-displacement naturally aspirated horizontally opposed engines and can be used in fields such as automotive range extenders and low-altitude aircraft.

[0035] I. System Overall Structure The crankcase ventilation system mainly includes an oil-gas separator 1, a timing cover 2, a crankcase pressure regulating valve 3, an intake manifold pressure regulating chamber 4, a first oil-gas separator 9, a left intake manifold 16, and a right intake manifold 17.

[0036] The oil-gas separator 1 and the timing cover 2 are fixedly connected by vibration friction welding. The connection structure between the two divides the internal space into three independent chambers: the left chamber 5, the right chamber 6 and the lower chamber 7.

[0037] The top of the oil-gas separator 1 is provided with a blow-by inlet 8. Blow-by gas from the crankcase enters the interior of the oil-gas separator 1 through the blow-by inlet 8 and flows to the left chamber 5 and the right chamber 6 respectively.

[0038] The oil-gas separator 1 is fixedly connected to the intake manifold pressure regulating chamber 4 by welding, first forming a sub-assembly, and then welding this sub-assembly to the timing cover 2 as a whole. This connection method eliminates the need for sealing rings and bolts, ensuring reliable sealing, short assembly time, and low cost.

[0039] The crankcase pressure regulating valve 3 is located in the internal space between the oil-gas separator 1 and the intake manifold pressure regulating chamber 4, that is, inside the welded sub-assembly. This built-in design avoids loosening or damage caused by external environment (high temperature, low temperature, high humidity, human factors), ensuring safety and reliability.

[0040] The left intake manifold 16 and the right intake manifold 17 are respectively located on both sides below the intake manifold pressure regulating chamber 4 and are connected to the intake manifold pressure regulating chamber 4, respectively corresponding to the left and right cylinders of the horizontally opposed engine.

[0041] II. Structure and Function of Each Chamber 1. Left chamber 5 The left chamber 5 is equipped with a first oil-gas separation device 9, which includes a perforated plate 12 and a nail plate 13. The perforated plate 12 has multiple small perforations to accelerate the airflow; the nail plate 13 is located on the opposite side of the perforated plate 12 and has multiple protruding nail-like structures for impacting and separating oil droplets.

[0042] The outlet of the left chamber 5 is connected to the intake manifold pressure regulating chamber 4 via the crankcase pressure regulating valve 3. The crankcase pressure regulating valve 3 has a one-way shut-off function.

[0043] 2. Right chamber 6 An air outlet is provided on the side wall of the right chamber 6. The air outlet is a throttling orifice 14. The right chamber 6 is connected to the clean side of the air filter through the air outlet.

[0044] 3. Lower chamber 7 The lower chamber 7 is the oil return chamber, located below the left chamber 5 and the right chamber 6. The lower chamber 7 is connected to the left chamber 5 via an oil return hole 10, and is also connected to the right chamber 6 via an oil return hole 10.

[0045] The bottom of the lower chamber 7 is connected to the narrow oil return channel 11 inside the engine cylinder. The separated oil flows into the oil pan through the oil return channel 11 inside the cylinder, realizing the closed circulation of the oil.

[0046] The body of the oil-gas separator 1 is sealed with the end of the sealing ring 15 to ensure the sealing performance of the connection.

[0047] III. Working Principle 1. Idle speed and low load conditions When the engine is idling or under light load, the throttle opening is small, and due to the throttle effect, the vacuum level in the intake manifold pressure regulating chamber 4 is very high.

[0048] Blow-by gas from the crankcase enters the oil-gas separator 1 through the blow-by gas inlet 8 and mainly flows to the left chamber 5. When the blow-by gas flows through the perforated plate 12 of the first oil-gas separator 9, the small perforations significantly increase the flow velocity. The high-speed blow-by gas impacts the opposite nail plate 13, and the small oil droplets in the blow-by gas impact the nail-shaped structure surface of the nail plate 13 due to inertia. The flow velocity drops sharply, and under the action of gravity, it flows downward along the surface of the nail plate 13 and flows into the lower chamber 7 through the oil return hole.

[0049] After oil-gas separation, the bypass gas flows through crankcase pressure regulating valve 3 into intake manifold pressure regulating chamber 4. Because the intake manifold vacuum is very high at this time, the spring in crankcase pressure regulating valve 3 is compressed by the negative pressure on the intake side, pushing the valve core towards the outlet side, gradually blocking the outlet passage and achieving a throttling effect. This controls the pressure on the intake side of crankcase pressure regulating valve 3, i.e., the crankcase pressure, preventing the crankcase pressure from becoming too low.

[0050] As the throttle opening increases, the pressure in the intake manifold gradually rises, the compression of the spring in the crankcase pressure regulating valve 33 decreases, the valve core retracts under the spring force, the cross-sectional area of ​​the outlet passage increases, and more blow-by gas from the crankcase enters the intake manifold.

[0051] 2. High load and full load conditions When the engine is under heavy or full load, the throttle opening is large, the vacuum in the intake manifold pressure regulating chamber 4 is small or even positive pressure, and the blow-by gas mainly flows out through the right chamber 6.

[0052] Blow-by gas from the crankcase enters the right chamber 6 through the blow-by gas inlet 8, and flows into the lower chamber 7 through the oil return hole under the action of gravity.

[0053] The separated blow-by gas flows into the clean side of the air filter through the outlet (throttle orifice 14) of the right chamber 6, and then enters the intake manifold through the throttle valve. The throttle orifice 14 can limit the flow of blow-by gas from the crankcase, keeping the crankcase pressure stable.

[0054] 3. Oil return process The oil separated from the left chamber 5 and the right chamber 6 flows into the lower chamber 7 through their respective return holes under the influence of gravity. The oil in the lower chamber 7 flows into the oil pan through the narrow return channel 11 inside the engine cylinder, realizing the closed-loop circulation and reuse of the oil.

[0055] The entire oil return passage 11 is located inside the oil-gas separator 1, timing cover 2, and engine block, and is not affected by the external environment, thus avoiding the risk of blockage or breakage of the oil return passage 11.

[0056] Example 2 The difference between this embodiment and Embodiment 1 is that the oil-gas separator 1 and the timing cover 2 are connected by hot plate welding. Hot plate welding is suitable for welding large-area plastic parts, and it provides high welding strength and good sealing performance.

[0057] The other structures and working principles of this embodiment are the same as those of Embodiment 1, and will not be repeated here.

[0058] Example 3 The difference between this embodiment and Embodiment 1 is that the oil-gas separator 1 and the timing cover 2 are connected by adhesive bonding. Adhesive bonding is suitable for complex structures and difficult welding applications, and offers flexibility in the process.

[0059] The other structures and working principles of this embodiment are the same as those of Embodiment 1, and will not be repeated here.

[0060] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall fall within the scope of the invention.

Claims

1. A crankcase ventilation system for a horizontally opposed engine, characterized in that: It includes an oil-gas separator (1), a timing cover (2), a crankcase pressure regulating valve (3), and an intake manifold pressure regulating chamber (4); the oil-gas separator (1) is fixedly connected to the timing cover (2), and the two form three independent chambers, including a left chamber (5), a right chamber (6), and a lower chamber (7); the oil-gas separator (1) is provided with a blow-by inlet (8), which is connected to the left chamber (5) and the right chamber (6) respectively; The left chamber (5) is equipped with a first oil-gas separator (9). The left chamber (5) is connected to the intake manifold pressure regulating chamber (4) through the crankcase pressure regulating valve (3). The right chamber (6) is equipped with an air outlet and is connected to the clean side of the air filter. The lower chamber (7) is an oil return chamber, which is connected to the left chamber (5) and the right chamber (6) through an oil return hole (10). The lower chamber (7) is also connected to the inside of the engine block through an oil return channel (11).

2. The crankcase ventilation system for a horizontally opposed engine according to claim 1, characterized in that: The oil-gas separator (1) and the intake manifold pressure regulating chamber (4) are fixedly connected by welding to form a sub-assembly, and then fixedly connected to the timing cover (2).

3. The crankcase ventilation system for a horizontally opposed engine according to claim 2, characterized in that: The crankcase pressure regulating valve (3) is located in the internal space between the oil-gas separator (1) and the intake manifold pressure regulating chamber (4).

4. A crankcase ventilation system for a horizontally opposed engine according to claim 3, characterized in that: The first oil-gas separation device (9) includes a perforated plate (12) for accelerating the airflow and a nail plate (13) for impacting and separating oil droplets.

5. A crankcase ventilation system for a horizontally opposed engine according to claim 4, characterized in that: The air outlet of the right chamber (6) is a throttling orifice (14).

6. A crankcase ventilation system for a horizontally opposed engine according to claim 5, characterized in that: The oil-gas separator (1) and the timing cover (2) are connected by welding or adhesive bonding.

7. A crankcase ventilation system for a horizontally opposed engine according to claim 6, characterized in that: The oil-gas separator (1) body is sealed with the engine cylinder block by the end of the sealing ring (15).

8. A crankcase ventilation system for a horizontally opposed engine according to claim 7, characterized in that: The intake manifold pressure regulating chamber (4) is also connected to the left intake manifold (16) and the right intake manifold (17).

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