Hydrogen engine
By designing fine connecting paths and rationally arranging the opening positions in the hydrogen engine, the problems of excessive pressure rise and flame propagation speed control caused by hydrogen combustion were solved, and the stability of pressure control and flame propagation was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- TOYOTA JIDOSHA KK
- Filing Date
- 2025-12-02
- Publication Date
- 2026-07-24
AI Technical Summary
In hydrogen engines, the flame generated by hydrogen combustion may flow through the connecting passage between the crankcase and the cylinder head, leading to excessive pressure rise and difficulty in controlling the flame propagation speed.
The design incorporates multiple connecting passages, with one or more passages being narrower than the others. The opening in the cylinder head is located above the oil level, while another or more passages are located below the oil level, in order to control the flame propagation speed and prevent oil blockage.
It effectively suppresses excessive pressure rise caused by hydrogen combustion, controls flame propagation speed, reduces flame area and chemical reaction amount, avoids the influence of engine oil on flame propagation, and facilitates adjustment of propagation speed.
Smart Images
Figure CN122447166A_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to hydrogen engines. Background Technology
[0002] Japanese Patent Application Publication No. 2005-140104 discloses an internal combustion engine. This internal combustion engine includes: a cylinder block, a crankcase connected to the lower part of the cylinder block, and a cylinder head connected to the upper part of the cylinder block. The aforementioned internal combustion engine has multiple connecting passages extending from the crankcase to the cylinder head.
[0003] In the case of hydrogen engines, sometimes a portion of the hydrogen injected into the combustion chamber leaks into the crankcase as blow-by gas and accumulates in the crankcase and cylinder head. This accumulated hydrogen can ignite and produce a flame. A flame originating in one of the crankcase or cylinder head components can potentially flow into the other through multiple pathways. Therefore, it is desirable to avoid excessive pressure rise caused by hydrogen combustion. Summary of the Invention
[0004] According to one aspect of this disclosure, a hydrogen engine is provided, comprising: a cylinder block; a crankcase connected to the lower part of the cylinder block; and a cylinder head connected to the upper part of the cylinder block. The hydrogen engine is provided with a plurality of connecting passages that connect the space inside the crankcase with the space inside the cylinder head, wherein one or more of the plurality of connecting passages is thinner than the remaining one or more of the plurality of connecting passages.
[0005] According to one aspect of this disclosure, a hydrogen engine is provided, comprising: a cylinder block; a crankcase connected to the lower part of the cylinder block; and a cylinder head connected to the upper part of the cylinder block. The hydrogen engine has a plurality of connecting passages that connect the space inside the crankcase with the space inside the cylinder head. The opening of one or more of the plurality of connecting passages into the space inside the cylinder head is located above the oil level inside the cylinder head. On the other hand, the opening of the remaining one or more of the plurality of connecting passages into the space inside the cylinder head is located below the oil level inside the cylinder head. Attached Figure Description
[0006] Figure 1 This is a diagram illustrating one embodiment of a hydrogen engine.
[0007] Figure 2 It is a diagram used to illustrate the speed of flame propagation.
[0008] Figure 3A This is a diagram illustrating the role of the comparative example.
[0009] Figure 3B It means Figure 1 The diagram shows the function of a hydrogen engine. Detailed Implementation
[0010] Hereinafter, a hydrogen engine according to one embodiment will be described with reference to the accompanying drawings.
[0011] <Structure of Hydrogen Engine 100>
[0012] Reference Figure 1 The structure of the hydrogen engine 100 will now be described. The hydrogen engine 100 includes: a cylinder block 10, a crankcase 12 connected to the lower part of the cylinder block 10, and a cylinder head 14 connected to the upper part of the cylinder block 10. A ventilation housing 14a is provided relative to the cylinder head 14.
[0013] The cylinder block 10 has a cylinder 34. A piston 36 reciprocates inside the cylinder 34. An intake passage 30 and an exhaust passage 32 are connected to the cylinder 34. The intake passage 30, from upstream, includes, in sequence: an air filter 38, a compressor 40a of a turbocharger 40, an intercooler 42, a throttle valve 44, and an intake manifold 46. The turbine impeller 40b of the turbocharger 40 is located in the exhaust passage 32.
[0014] The blow-by passage 50 extends from the crankcase 12 to the intake manifold 46. The blow-by passage 50 extends inside the cylinder block 10, the cylinder head 14, and the ventilation housing 14a. A PCV (Positive Crankcase Ventilation) valve 48 is located in the blow-by passage 50 between the intake manifold 46 and the ventilation housing 14a. The PCV valve 48 adjusts the amount of blow-by gas flowing in the blow-by passage 50.
[0015] The return passage 52 extends from the portion between the air filter 38 and the compressor 40a in the intake passage 30 to the ventilation housing 14a. The ventilation housing 14a communicates with the cylinder head 14. Multiple connection passages 20 are provided to connect the space inside the crankcase 12 with the space inside the cylinder head 14.
[0016] <Structure of multiple connected paths 20>
[0017] Multiple connecting passages 20 include connecting passage 20a and connecting passage 20b. Connecting passage 20a has an opening 22a that opens into a space within the cylinder head 14. The opening 22a is located above the oil level OS within the cylinder head 14. Connecting passage 20a is disposed outside the cylinder block 10. Connecting passage 20a is a pipe or hose. Connecting passage 20b has an opening 22b that opens into a space within the cylinder head 14. The opening 22b is located below the oil level OS within the cylinder head 14. Connecting passage 20b is disposed inside the cylinder block 10. Connecting passage 20b is a passage for returning engine oil supplied to components in the cylinder head 14 to the crankcase 12. The number of connecting passages 20a can be one or more. The number of connecting passages 20b can be one or more.
[0018] like Figure 1 As shown, connected path 20a is thinner than connected path 20b. That is, one or more connected paths 20 are thinner than the remaining one or more connected paths 20.
[0019] <The function of this implementation method>
[0020] When the intake manifold 46 becomes negatively pressurized, the PCV valve 48 opens. As a result, air flows in the following order: return path 52, ventilation housing 14a, cylinder head 14, connecting paths 20a and 20b, crankcase 12, and blow-by passage 50. This allows blow-by gas accumulated in the crankcase 12 to flow into the intake passage 30.
[0021] The hydrogen engine 100 includes: a cylinder block 10, a crankcase 12 connected to the lower part of the cylinder block 10, and a cylinder head 14 connected to the upper part of the cylinder block 10. It is provided with a plurality of connecting passages 20 that connect the space within the crankcase 12 to the space within the cylinder head 14. One or more of the connecting passages 20 are thinner than the remaining connecting passages 20.
[0022] The smaller the diameter of the connecting path 20, the faster the flame propagation speed U in the multiple connecting paths 20.
[0023] Reference Figure 2 Let's explain the flame front movement speed, or propagation speed U. When hydrogen, which accumulates as fly ash, ignites and produces a flame, a flame front is formed, serving as the boundary between the combusted and uncombustible gases. The flame front movement speed, or propagation speed U, is the sum of the turbulent combustion speed St and the flow velocity Adv caused by the expansion of the combusted gases.
[0024] Reference Figure 3A and Figure 3B The reason why the smaller the diameter of the connecting path 20, the faster the propagation speed U of the flame surface in the connecting path 20 is will be explained. Figure 3AThis is a comparative example where connecting paths 20A and 20B have the same diameter. Figure 3A The thick curve in crankcase 12 represents the current flame face. Figure 3A The thick curve in the cylinder head 14 represents the flame face moving from the crankcase 12 to the cylinder head 14. Figure 3B This embodiment indicates that connecting path 20a is thinner than connecting path 20b. Figure 3B The thick curve in crankcase 12 represents the current flame face. Figure 3B The thick curve in the cylinder head 14 represents the flame face moving from the crankcase 12 to the cylinder head 14.
[0025] The process of the flame generated in the crankcase 12 flowing into the cylinder head 14 via connecting passages 20a and 20b will be explained. As the flame surface expands in the crankcase 12, it reaches the portion of the connecting passage 20 that opens into the crankcase 12. As described above, the propagation velocity U is the sum of the turbulent combustion velocity St and the flow velocity Adv caused by the expansion of the combustible gas. Because the flow velocity Adv is caused by the expansion of the combustible gas, the smaller the cross-sectional area of the connecting passage 20, the faster the flow velocity Adv. Therefore, the propagation velocity U of the flame surface in the connecting passage 20 increases as the diameter of the connecting passage 20 decreases.
[0026] exist Figure 3A In the comparative example shown, the connecting passages 20A and 20B have the same diameter. Therefore, there is a high probability that the flames generated in the crankcase 12 will reach the cylinder head 14 almost simultaneously.
[0027] In contrast, in this embodiment, the connecting path 20a is narrower than the connecting path 20b. Therefore, a flame moving through the narrow connecting path 20a is more likely to reach the cylinder head 14 before a flame moving through the wide connecting path 20b.
[0028] <Effects of this implementation method>
[0029] (1) As described above, the flame moving through the narrow connecting path 20a is more likely to reach the cylinder head 14 first than the flame moving through the thick connecting path 20b. Therefore, this embodiment is more likely to suppress excessive pressure rise compared to the comparative example.
[0030] The reasons why this embodiment is more effective at suppressing excessive pressure rise compared to the comparative example will be explained. The amount of chemical reaction generated at the flame surface is proportional to the turbulent combustion rate St, the density of unburned gas, and the flame surface area, i.e., the flame area. Figure 3A In the comparative example shown, the flame generated in the space within the crankcase 12 is highly likely to arrive at the space within the cylinder head 14 almost simultaneously, therefore... Figure 3BThe flame area in this embodiment can be increased more easily than in the comparative example. A larger flame area means a greater amount of chemical reaction can also be achieved. This means a greater increase in pressure caused by the chemical reaction can also be achieved. Therefore, in this embodiment, excessive pressure rise is more easily suppressed compared to the comparative example.
[0031] The above describes the situation where the flame generated in the crankcase 12 flows into the cylinder head 14 via connecting passages 20a and 20b. The same applies to the situation where the flame generated in the cylinder head 14 flows into the crankcase 12 via connecting passages 20a and 20b.
[0032] (2) One or more of the multiple connecting paths 20 include a connecting path 20a that is narrower than the remaining one or more of the multiple connecting paths 20 and has an opening 22a that opens into the space inside the cylinder head 14 and is located above the oil level OS inside the cylinder head 14.
[0033] The aforementioned hydrogen engine 100 includes an opening 22a leading to a space within the cylinder head 14, and a narrow connecting passage 20a positioned above the oil level OS within the cylinder head 14. Because this narrow connecting passage 20a has an opening 22a positioned above the oil level OS within the cylinder head 14, it is less likely that engine oil will obstruct the propagation of the flame through this narrow connecting passage 20a. Therefore, the possibility of the flame generated in the crankcase 12 reaching the cylinder head 14 almost simultaneously is further reduced. Thus, according to the above structure, excessive pressure rise is easily suppressed.
[0034] (3) One or more of the multiple connecting paths 20 includes a connecting path 20a that is thinner than the remaining one or more of the multiple connecting paths 20 and is disposed outside the cylinder block 10.
[0035] According to the above structure, the propagation speed U can be easily adjusted by changing the communication path 20a disposed on the outside of the cylinder block 10. The propagation speed U can be easily adjusted without changing the internal structure of the cylinder block 10.
[0036] (4) The hydrogen engine 100 includes: a cylinder block 10, a crankcase 12 connected to the lower part of the cylinder block 10, and a cylinder head 14 connected to the upper part of the cylinder block 10. Multiple connecting passages 20 are provided to connect the space inside the crankcase 12 with the space inside the cylinder head 14. The opening 22a of one or more of the multiple connecting passages 20, which opens into the space inside the cylinder head 14, is located above the oil level OS inside the cylinder head 14. The opening 22b of the remaining one or more of the multiple connecting passages 20, which opens into the space inside the cylinder head 14, is located below the oil level OS inside the cylinder head 14.
[0037] In the connecting passage 20b, where the opening 22b into the space within the cylinder head 14 is located below the oil level OS within the cylinder head 14, oil blockage in the connecting passage 20b easily reduces the flame propagation speed U. Therefore, according to the above structure, the probability of the flame generated in the crankcase 12 reaching the cylinder head 14 almost simultaneously is low. Similarly, the probability of the flame generated in the cylinder head 14 reaching the crankcase 12 almost simultaneously is low. Therefore, excessive pressure rise caused by the combustion of hydrogen accumulated as blow-by gas is easily avoided.
[0038] (5) One or more of the multiple connecting paths 20 include an opening 22a that opens into the space inside the cylinder head 14 and is located above the oil level OS inside the cylinder head 14 and is disposed outside the cylinder block 10.
[0039] According to the above structure, the propagation speed U can be easily adjusted by changing the communication path 20a disposed on the outside of the cylinder block 10. The propagation speed U can be easily adjusted without changing the internal structure of the cylinder block 10.
[0040] <Example of Change>
[0041] This embodiment can be implemented by modification as follows. This embodiment and the following modifications can be combined with each other within the scope of technical inconsistency.
[0042] In the above embodiment, the opening 22a of the connecting passage 20a is located above the oil level OS inside the cylinder head 14. Alternatively, the opening 22a may be located below the oil level OS.
[0043] In the above embodiment, the connecting passage 20a is disposed on the outside of the cylinder block 10. Alternatively, the connecting passage 20a may be disposed inside the cylinder block 10.
[0044] In the above embodiment, the connecting passage 20a is thinner than the connecting passage 20b. Alternatively, the diameter of the connecting passage 20a can be the same as the diameter of the connecting passage 20b. The opening 22a leading to the space inside the cylinder head 14 is located above the oil level OS inside the cylinder head 14. Therefore, it is easy to avoid a situation where the flame propagation speed U in the connecting passage 20a decreases due to oil blockage. Therefore, the possibility that the flame generated in the crankcase 12 reaches the cylinder head 14 almost simultaneously through the connecting passages 20a and 20b is low.
Claims
1. A hydrogen engine, comprising: Cylinder block; The crankcase is connected to the lower part of the cylinder block; and The cylinder head is connected to the upper part of the cylinder block. The hydrogen engine has multiple connecting passages that connect the space inside the crankcase with the space inside the cylinder head, and one or more of the multiple connecting passages are thinner than the remaining one or more of the multiple connecting passages.
2. The hydrogen engine according to claim 1, wherein, One or more of the plurality of connecting paths include a connecting path that is narrower than one or more of the remaining connecting paths and whose opening into the space inside the cylinder head is located above the oil level inside the cylinder head.
3. The hydrogen engine according to claim 1 or 2, wherein, One or more of the plurality of connecting paths include a connecting path that is thinner than one or more of the remaining connecting paths and is disposed outside the cylinder block.
4. A hydrogen engine, comprising: Cylinder block; The crankcase is connected to the lower part of the cylinder block; and The cylinder head is connected to the upper part of the cylinder block. The hydrogen engine has multiple connecting passages that connect the space inside the crankcase with the space inside the cylinder head. The opening of one or more of the multiple connecting passages into the space inside the cylinder head is located above the oil level inside the cylinder head. On the other hand, the opening of the remaining one or more of the multiple connecting passages into the space inside the cylinder head is located below the oil level inside the cylinder head.
5. The hydrogen engine according to claim 4, wherein, One or more of the plurality of connecting paths include: an opening that opens into the space inside the cylinder head and is located above the oil level inside the cylinder head, and is disposed outside the cylinder block.