Residual hydrogen and water vapor treatment system for crankcase of hydrogen energy engine

Abstract

The invention belongs to the technical field of internal combustion engines, particularly discloses a hydrogen energy engine crankcase residual hydrogen and water vapor treatment system, and aims to solve the problems of potential safety hazards caused by hydrogen accumulation and engine oil emulsification caused by water vapor condensation in the prior art. The system comprises key components such as a crankcase, an oil-gas separator, a Venturi tube, a fireproof assembly and a hydrogen concentration alarm. Hydrogen-containing gas in the crankcase is driven to flow through negative pressure generated by the Venturi effect, and hydrogen is promoted to spontaneously combust by high-temperature gas introduced by the catalytic converter, so that residual hydrogen and water vapor are safely discharged. Meanwhile, the system is provided with a hydrogen concentration sensor and an alarm, the hydrogen concentration is monitored in real time, and safe operation is ensured. The system does not need complex anti-explosion design, has the advantages of being high in safety, high in environmental protection performance, good in economical efficiency and the like, and is suitable for hydrogen energy engines and other gas fuel engines.

Description

Technical Field

[0001] The present invention relates to the technical field of internal combustion engines, and particularly to a system for treating residual hydrogen and water vapor in the crankcase of a hydrogen energy engine, which is applicable to various gas fuel engines, and especially applicable to a hydrogen energy engine system. Background Art

[0002] The crankcase ventilation system of traditional internal combustion engines usually reintroduces lubricating oil vapor and fuel vapor into the intake system for combustion, and dilutes the gas in the crankcase with fresh air to reduce the concentration of combustibles. However, the gas components in the crankcase of a hydrogen energy engine are significantly different from those of a conventional internal combustion engine, which mainly consists of air, hydrogen, and a small amount of lubricating oil vapor. Due to the extremely small molecular weight of hydrogen, it is very easy to penetrate into the crankcase through the micro-gaps of seals. When the mixing concentration of hydrogen and air exceeds 4% (volume fraction), if it contacts a fire source (such as frictional high temperature or electrostatic spark), it will cause violent combustion or even explosion, seriously threatening the safety of vehicles and personnel.

[0003] In the prior art, the solution of introducing gas into the intake system for secondary combustion through the crankcase ventilation pipeline has significant defects: on the one hand, hydrogen molecules have strong diffusivity and low density, and it is difficult for the traditional pipeline system to effectively discharge hydrogen, resulting in continuous accumulation of hydrogen in the crankcase; on the other hand, the method relying on dilution with fresh air has limited efficiency and cannot completely eliminate the explosion risk of high-concentration hydrogen. In addition, the existing explosion-proof designs (such as adding complex sensors or redundant sealing structures) have problems of high cost and high system complexity, and it is difficult to meet the actual application requirements.

[0004] More seriously, the product of hydrogen combustion (water vapor) is likely to condense in the crankcase under low-temperature conditions. After mixing with engine oil, it may cause engine oil emulsification, resulting in lubrication failure and wear of key components. The existing ventilation system lacks targeted treatment for this, further exacerbating the safety hazards and maintenance burden of the hydrogen energy engine.

[0005] Therefore, there is an urgent need for an innovative solution that can efficiently discharge the residual hydrogen and water vapor in the crankcase, avoid explosion risks, and does not rely on complex explosion-proof designs, so as to promote the safe and practical development of hydrogen energy engine technology. Summary of the Invention

[0006] The purpose of the present invention is to provide a system for treating residual hydrogen and water vapor in the crankcase of a hydrogen energy engine to solve the above problems existing in the prior art.

[0007] To achieve the above purpose, the present invention provides the following solution: A system for treating residual hydrogen and water vapor in the crankcase of a hydrogen energy engine, comprising:

[0008] A crankcase, which has a ventilation air inlet and a ventilation air outlet;

[0009] An oil-gas separator, the inlet end of the oil-gas separator is communicated with the ventilation exhaust port, the exhaust end is connected to a first exhaust pipe, and the first exhaust pipe is communicated with the engine exhaust pipe;

[0010] An oil return passage, one end of the oil return passage is fixedly connected and communicated at the bottom of the oil-gas separator, and the other end is fixedly connected and communicated with the crankcase. The separated oil enters the oil return passage by gravity and flows back to the crankcase along the oil return passage;

[0011] A Venturi tube, the Venturi tube is arranged at the intersection of the first exhaust pipe and the engine exhaust pipe. The Venturi tube includes a contraction section, a throat section and a diffusion section, and an A port, a B port and a C port are respectively arranged at the starting end of the contraction section, the throat section and the end of the diffusion section. The A port is connected to a catalytic converter, the B port is connected to the first exhaust pipe, and the C port is connected to the end of the engine exhaust pipe; the Venturi tube forms a negative pressure at the B port through the Venturi effect to drive the hydrogen-containing gas in the crankcase to flow in, and uses the high-temperature gas introduced from the catalytic converter to promote the self-ignition of the hydrogen-containing gas.

[0012] In some alternative embodiments of the present invention, a ventilation outlet check valve is provided on the first exhaust pipe between the oil-gas separator and the Venturi tube.

[0013] In some alternative embodiments of the present invention, a fire prevention component is further provided on the first exhaust pipe between the oil-gas separator and the Venturi tube.

[0014] In some alternative embodiments of the present invention, the fire prevention component is a fire prevention metal mesh arranged in the inner cavity of the metal pipe.

[0015] In some alternative embodiments of the present invention, a ventilation air supply check valve is provided at the ventilation air supply port of the crankcase.

[0016] In some alternative embodiments of the present invention, a hydrogen concentration sensor is provided at the top inside the crankcase, and the hydrogen concentration sensor is used to monitor the hydrogen concentration inside the crankcase in real time.

[0017] In some alternative embodiments of the present invention, a hydrogen concentration alarm is further provided on the engine exhaust pipe at the rear end of the C port of the Venturi tube.

[0018] In some alternative embodiments of the present invention, the hydrogen concentration alarm includes a hydrogen concentration sensor and an audible and visual alarm, and the hydrogen concentration sensor is electrically connected to a data recording and transmission module.

[0019] In some alternative embodiments of the present invention, a labyrinth structure is provided inside the oil-gas separator for separating the oil and gas in the crankcase gas.

[0020] In some alternative embodiments of the present invention, the Venturi tube is made of stainless steel.

[0021] The present invention discloses the following technical effects:

[0022] The present invention provides a system for treating residual hydrogen and water vapor in the crankcase of a hydrogen engine. By newly designing the crankcase ventilation pipeline, without the need for an additional electric actuator, the Venturi tube structure is utilized to drive the flow of crankcase gas, the metal temperature of the exhaust pipe is used to ignite hydrogen, and the combustion gas containing water vapor is discharged through the exhaust pipe, avoiding the risks of explosion in the crankcase of a hydrogen engine and high water content in the engine oil. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0024] Figure 1 It is a schematic diagram of the system for treating residual hydrogen and water vapor in the crankcase of the hydrogen engine of the present invention;

[0025] Figure 2 It is a schematic structural diagram of the stainless steel Venturi tube in the treatment system of the present invention.

[0026] In the figure: 1, crankcase; 2, ventilation air supply check valve; 3, oil-gas separator; 4, ventilation outlet check valve; 5, fire prevention component; 6, Venturi tube; 7, hydrogen concentration alarm; 8, catalytic converter; 9, oil return passage; 10, first exhaust pipe. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0028] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0029] Referring to Figure 1 and Figure 2 As shown, the present invention provides a system for treating residual hydrogen and water vapor in the crankcase of a hydrogen engine, including a crankcase 1, an oil-gas separator 3, a fire prevention component 5, a Venturi tube 6, a hydrogen concentration alarm 7, a catalytic converter 8, and an oil return passage 9.

[0030] In this embodiment, the crankcase 1 is a part of the hydrogen engine body, which is used to accommodate and protect transmission components such as the crankshaft and connecting rod, and at the same time provide a relatively enclosed and stable environment for these components to ensure the normal operation of the hydrogen engine. During the operation of the hydrogen engine, a certain amount of gas will be generated in the crankcase 1, and the gas contains hydrogen.

[0031] The explosion process of the crankcase 1 of a hydrogen engine is usually closely related to hydrogen leakage. Hydrogen molecules are very small and easily leak through the tiny gaps of the seals. During the operation of the engine, incomplete sealing of the piston rings may cause hydrogen in the combustion chamber to leak into the crankcase 1. Once hydrogen enters the crankcase 1, it will mix with air to form an explosive mixture.

[0032] When the hydrogen concentration in the crankcase 1 reaches 4% - 75% (volume fraction), this mixture is within the explosion limit range. At this time, if there are ignition sources such as high temperature, sparks, static electricity, or heat generated by bearing friction, an explosion may be triggered. For example, the high-temperature components inside the engine or the heat generated by mechanical friction may become ignition sources.

[0033] Therefore, the explosion risk of the crankcase 1 of a hydrogen engine needs to be controlled through strict sealing design, real-time monitoring of hydrogen concentration, and optimization of the ventilation system.

[0034] In this embodiment, the crankcase 1 is made of high-strength aluminum alloy material, and a hydrogen concentration sensor (integrated on the top of the box body) is provided inside. The hydrogen concentration sensor monitors the hydrogen concentration in real time. The crankcase 1 has a ventilation air inlet and a ventilation air outlet. A ventilation air inlet check valve 2 is installed at the ventilation air inlet, which only allows external fresh air to flow in one way, and is used to dilute the hydrogen in the box. The ventilation air outlet is connected to an oil-gas separator 3 through a pipeline.

[0035] In this embodiment, the inlet end of the oil-gas separator 3 is connected to the ventilation air outlet, and the exhaust end is connected to a first exhaust pipe 10, and the first exhaust pipe 10 is connected to the engine exhaust pipeline. The oil-gas separator 3 is connected to the crankcase 1 through a high-temperature resistant rubber hose, and is used to separate the oil and gas in the gas of the crankcase 1. The separated oil flows back to the crankcase 1 through an oil return passage 9, reducing the oil loss.

[0036] In a specific embodiment, a spiral maze structure is provided inside the oil-gas separator 3 to reduce the gas flow rate and efficiently separate the oil and gas.

[0037] In this embodiment, the oil return passage 9 is connected to the bottom of the oil-gas separator 3 and communicates with the crankcase 1. The oil separated by the oil-gas separator 3 flows back to the bottom of the crankcase 1 along the oil return passage 9 under the action of gravity and mixes with the engine oil.

[0038] In this embodiment, the fire prevention component 5 is composed of a metal pipe and a multi-layer honeycomb fire prevention metal net inside, and is installed at the outlet end of the oil-gas separator 3. It can withstand the high temperature from the engine exhaust pipe, prevent the reverse propagation of flames, and avoid the gas in the front-section pipeline from being ignited by high temperature or fire sources.

[0039] In this embodiment, a ventilation and exhaust check valve 4 is provided on the first exhaust pipe 10 between the oil-gas separator 3 and the Venturi tube 6. Both the ventilation and exhaust check valve 4 and the fire prevention component 5 are located on the first exhaust pipe 10, and their installation positions are adjustable.

[0040] In this embodiment, the Venturi tube 6 is connected to the exhaust pipe. The Venturi tube 6 is arranged at the intersection of the first exhaust pipe 10 and the engine exhaust pipe. The Venturi tube 6 includes a contraction section, a throat section, and a diffusion section, and an A port, a B port, and a C port are respectively provided at the start of the contraction section, the throat section, and the end of the diffusion section. The A port is connected to the catalytic converter 8, the B port is connected to the first exhaust pipe 10, and the C port is connected to the end of the engine exhaust pipe. The Venturi effect forms a negative pressure at the B port to drive the gas flow in the crankcase 1; the A port introduces high-temperature exhaust gas (above 800 °C), and uses the high temperature to promote the spontaneous combustion of hydrogen and discharge water vapor.

[0041] The Venturi effect is a phenomenon in fluid mechanics, which refers to the phenomenon that when a fluid (gas or liquid) flows through a narrow section with a suddenly reduced cross-sectional area in a pipeline, the flow rate will increase, and at the same time the static pressure will decrease. Its core principle is Bernoulli's law (the pressure will drop when the kinetic energy of the fluid increases). The Venturi tube 6 usually consists of three parts: a contraction section, a throat section, and a diffusion section. The contraction section accelerates the fluid flow rate, resulting in the lowest pressure at the narrowest part of the throat section. The flow rate and pressure are restored in the diffusion section.

[0042] The hydrogen-containing gas is mixed with the high-temperature exhaust gas at the throat of the Venturi tube 6, and the temperature instantaneously rises above 570 °C, triggering the spontaneous combustion reaction of hydrogen. The water vapor produced by combustion is discharged from the C port along with the tail gas, avoiding condensation into the crankcase 1.

[0043] In a specific embodiment, as Figure 2 shown, the diameter d of the throat section is 1 / 3 of that from the engine exhaust pipe to D. The cone angles of the contraction section and the diffusion section are 15° - 20° and 12° - 18° respectively. The A port is connected to the catalytic converter 8 to introduce high-temperature exhaust gas above 800 °C; the B port is connected to the first exhaust pipe 10 through a flange, and a negative pressure of -10 kPa is formed at the throat using the Venturi effect to drive the gas flow in the crankcase 1; the C port is connected to the tail gas discharge pipe (i.e., the end of the engine exhaust pipe), and the water vapor after combustion is discharged therefrom.

[0044] It should be understood that in practical applications, for engines with different displacements, the ratio of the throat diameter d of the venturi tube 6 to the diameter D of the engine exhaust pipe is adjusted to satisfy 0.25D ≤ d ≤ 0.4D to ensure the matching of negative pressure efficiency and flow rate.

[0045] In a specific embodiment, the venturi tube 6 is made of stainless steel.

[0046] In a specific embodiment, the inner wall of the venturi tube 6 is coated with ceramics to improve the high-temperature resistance performance (up to 1200 °C) and extend the service life.

[0047] In this embodiment, a hydrogen concentration alarm 7 is further provided on the engine exhaust pipe at the rear end of the C port of the venturi tube 6. The hydrogen concentration alarm 7 can be located inside the rear pipe of the stainless steel venturi tube 6 or at a position near the exhaust gas that can be contacted. The hydrogen concentration alarm 7 can test the hydrogen concentration in the gas and give an alarm to avoid potential safety hazards caused by system failure.

[0048] Specifically, in an optional embodiment, the hydrogen concentration alarm 7 is integrated downstream of the C port of the venturi tube 6 and uses an electrochemical sensor with a detection range of 0 - 10% (volume concentration). When it exceeds 4%, it triggers an audible and visual alarm and transmits data to the vehicle-mounted ECU through the CAN bus.

[0049] In a specific embodiment, the hydrogen concentration alarm 7 includes a hydrogen concentration sensor and an audible and visual alarm, and the hydrogen concentration sensor is electrically connected to a data recording and transmission module.

[0050] In some optional embodiments, the hydrogen and water vapor treatment system for the crankcase of the hydrogen energy engine further includes an intelligent control system, specifically a PID controller, which dynamically adjusts the opening degree of the air intake check valve according to the data of the hydrogen concentration sensor to achieve closed-loop control. During the low-temperature startup stage (<50 °C), the electric heating module is started to preheat the venturi tube 6 to ensure the reliability of hydrogen self-ignition.

[0051] In some optional embodiments, a booster pump is added at the A port of the venturi tube 6 to compensate for the insufficient negative pressure caused by the thin air when applied in high-altitude areas.

[0052] The working principle and process of the embodiment of the present invention are as follows:

[0053] When the engine starts to work, high-temperature exhaust gas and crankcase 1 gas are generated. The crankcase 1 gas accumulates in the crankcase 1, and the temperature of the high-temperature exhaust gas further rises to over 800 °C after flowing through the catalytic converter 8. Subsequently, the high-temperature exhaust gas enters the venturi tube 6 through the A port of the venturi tube 6. Under the action of the venturi effect, a negative pressure is formed at the B port of the venturi tube 6.

[0054] At this time, the pressure of the gas in the crankcase 1 is atmospheric pressure at the front end of the first exhaust pipe 10 and negative pressure at the rear end. Under the action of the pressure difference, the gas in the crankcase 1 begins to flow along the first exhaust pipe 10 towards the venturi tube 6. At the same time, fresh air enters the crankcase 1 through the ventilation air supply check valve 2, mixes with the gas in the crankcase 1, and dilutes the hydrogen concentration and water vapor in the crankcase 1.

[0055] The diluted gas in the crankcase 1 first flows through the oil-gas separator 3. In the oil-gas separator 3, the gas undergoes maze deceleration and then completes the oil-liquid separation. The separated liquid enters the bottom of the crankcase 1 through the oil return passage 9 and mixes with the engine oil; the separated hydrogen-containing gas then flows through the fireproof metal mesh through the ventilation outlet check valve 4 and finally enters through port B of the venturi tube 6.

[0056] At this time, the high-temperature exhaust gas processed by the catalytic converter 8 and the high-temperature metal wall surface meet the hydrogen-containing gas. The hydrogen-containing gas spontaneously ignites under high-temperature conditions, generating water and the hydrogen disappears. At the same time, the water vapor in the crankcase 1 is also discharged through this passage and enters the atmosphere.

[0057] In a specific experimental example, the following experimental data were obtained using the hydrogen engine crankcase residual hydrogen and water vapor treatment system according to the embodiment of the present invention:

[0058] parameter measured value industry standard hydrogen concentration in crankcase 1 ≤1.8％ ≤4％ oil-gas separation efficiency 97％ ≥85％ self-ignition trigger temperature 580℃ ≥570℃ system response time 2.3s ≤5s

[0059] Compared with the prior art, the embodiment of the present invention discloses at least the following beneficial effects:

[0060] In terms of safety, through the dual mechanisms of negative pressure drive and high-temperature spontaneous combustion, the hydrogen concentration in the crankcase 1 is controlled below the lower explosion limit, and no additional explosion-proof structure is required.

[0061] In terms of environmental protection, the catalytic converter 8 synchronously treats pollutants such as NOx, and the tail gas emissions meet the national VI standards.

[0062] In terms of economy, the oil-gas separation efficiency is ≥95%, and the engine oil replacement cycle is extended by 30%; the system has no electric components, and the maintenance cost is reduced by 40%.

[0063] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0064] The embodiments described above are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the spirit of the present invention's design, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A hydrogen engine crankcase residual hydrogen and water vapor treatment system, characterized in that: include: A crankcase (1), wherein the crankcase (1) has a ventilation air supply port and a ventilation air exhaust port; An oil-gas separator (3), the inlet end of the oil-gas separator (3) being in communication with the ventilation exhaust port, the exhaust end of the oil-gas separator (3) being connected to a first exhaust pipe (10), and the first exhaust pipe (10) being in communication with an exhaust pipeline of the engine; An oil return passage (9), one end of which is fixedly connected to and communicated with the bottom of the oil-gas separator (3), and the other end of which is fixedly connected to and communicated with the crankcase (1); separated oil enters the oil return passage (9) by gravity and flows back to the crankcase (1) along the oil return passage (9); A venturi tube (6) is provided at the intersection of a first exhaust pipe (10) and an engine exhaust pipeline, the venturi tube (6) comprises a contraction section, a throat section and a diffusion section, and is provided with an A port, a B port and a C port at the beginning of the contraction section, the throat section and the end of the diffusion section, respectively, the A port is connected to a catalytic converter (8), the B port is connected to the first exhaust pipe (10), and the C port is connected to the end of the engine exhaust pipeline; the venturi tube (6) forms a negative pressure at the B port through the venturi effect to drive the hydrogen-containing gas in the crankcase (1) to flow in, and uses the high-temperature gas introduced from the catalytic converter (8) to promote the self-ignition of the hydrogen-containing gas.

2. The hydrogen engine crankcase residual hydrogen and water vapor treatment system according to claim 1, characterized in that: A ventilation and air outlet one-way valve (4) is provided on the first exhaust pipe (10) between the oil-gas separator (3) and the venturi tube (6).

3. The hydrogen engine crankcase residual hydrogen and water vapor treatment system according to claim 1, characterized in that: A fireproof component (5) is also provided on the first exhaust pipe (10) between the oil-gas separator (3) and the venturi tube (6).

4. The hydrogen engine crankcase residual hydrogen and water vapor treatment system according to claim 3, characterized in that: The fireproof component (5) is a fireproof metal mesh arranged in the inner cavity of the metal tube.

5. The hydrogen engine crankcase residual hydrogen and water vapor treatment system according to claim 1, characterized in that: The ventilation and air supply port of the crankcase (1) is provided with a ventilation and air supply one-way valve (2).

6. The hydrogen engine crankcase residual hydrogen and water vapor treatment system according to claim 1, characterized in that: A hydrogen concentration sensor is provided at the top of the crankcase (1), and the hydrogen concentration sensor is used to monitor the hydrogen concentration in the crankcase (1) in real time.

7. The hydrogen engine crankcase residual hydrogen and water vapor treatment system according to claim 1, characterized in that: A hydrogen concentration alarm (7) is also provided on the engine exhaust pipeline at the rear end of the C port of the venturi tube (6).

8. The hydrogen engine crankcase residual hydrogen and water vapor treatment system according to claim 7, characterized in that: The hydrogen concentration alarm (7) comprises a hydrogen concentration sensor and an audible and visual alarm, and the hydrogen concentration sensor is connected to a data recording and transmission module by telecommunication.

9. The hydrogen engine crankcase residual hydrogen and water vapor treatment system according to claim 1, characterized in that: The oil-gas separator (3) is provided with a labyrinth structure inside, which is used to separate the oil and gas in the crankcase (1).

10. The hydrogen engine crankcase residual hydrogen and water vapor treatment system according to claim 1, characterized in that: The Venturi tube (6) is made of stainless steel.

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