Hydrogen engine

Abstract

A hydrogen engine is provided which reduces the possibility of damage to an injector that injects hydrogen due to the influence of heat in a combustion chamber. A hydrogen engine (1) that supplies hydrogen as fuel into a combustion chamber (7) has an injector (51) that injects hydrogen, a pressure accumulation chamber (61) that communicates with an injection hole (52) of the injector, a communication hole (62) that communicates with the pressure accumulation chamber and the combustion chamber, and a pressure accumulation chamber defining portion (63) that is provided between the injector and the combustion chamber and defines the pressure accumulation chamber and the communication hole. The pressure accumulation chamber defining portion is formed separately from the injector and has a thermal conductivity that is higher than the thermal conductivity of a combustion chamber wall that defines the combustion chamber.

Description

Technical Field

[0001] This disclosure relates to hydrogen engines. Background Technology

[0002] Previously, engines that directly inject gaseous fuel into the combustion chamber were known (Patent Documents 1 and 2). In particular, Patent Document 1 disclosed an engine that uses hydrogen as gaseous fuel. Furthermore, in the rotary engine described in Patent Document 1, a hydrogen injector is arranged facing the combustion chamber 100° ahead of the top dead center of the compression stroke. As a result, even if premature ignition occurs in the combustion chamber, the hydrogen injector is located at the end of the flame and pressure wave, thus reducing the risk of damage to the hydrogen injector.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2007-162633

[0006] Patent Document 2: Japanese Patent Application Publication No. 2002-221037 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] Furthermore, hydrogen burns rapidly, has a low minimum ignition energy, and a wide combustible range when mixed with air, making it easy for the flame to reach the vicinity of the combustion chamber walls. Therefore, if the hydrogen injector is positioned facing the combustion chamber, even if it is located in a position where the flame and pressure waves are not easily accessible, the possibility of the hydrogen injector being damaged by the heat from the combustion chamber cannot be sufficiently reduced.

[0009] In view of the above issues, the purpose of this disclosure is to reduce the possibility of damage to the hydrogen injector due to the heat inside the combustion chamber.

[0010] Methods for solving problems

[0011] The main purpose of this disclosure is as follows.

[0012] (1) A hydrogen engine that supplies hydrogen as fuel to a combustion chamber, wherein:

[0013] The injector sprays hydrogen gas.

[0014] The accumulator chamber is connected to the nozzle of the injector;

[0015] The connecting hole communicates with the accumulator chamber and the combustion chamber; and

[0016] A pressure accumulator defining section is provided between the injector and the combustion chamber, defining the pressure accumulator chamber and the communicating hole.

[0017] The accumulator chamber is formed separately from the injector and has thermal conductivity greater than that of the combustion chamber wall that defines the combustion chamber.

[0018] (2) The hydrogen engine described in (1) above,

[0019] There is one or more connecting holes.

[0020] At least one of the connecting holes is formed as an axis having an angle relative to the axis of the nozzle of the injector.

[0021] (3) The hydrogen engine described in (2) above,

[0022] It also has a piston that reciprocates within a cylinder that defines the combustion chamber.

[0023] At least one of the connecting holes is formed as an axis that extends obliquely toward the piston side in the injection direction relative to the axis of the nozzle of the injector.

[0024] (4) The hydrogen engine according to (2) or (3) above,

[0025] It also includes a spark plug configured to be exposed to the combustion chamber and to ignite the hydrogen-air mixture.

[0026] At least one of the connecting holes is formed as having an axis that extends obliquely from the ignition portion of the spark plug relative to the axis of the injector's nozzle.

[0027] (5) The hydrogen engine described in (4) above,

[0028] There are two or more connecting holes.

[0029] At least two of the connecting holes are formed with an axis extending laterally in a direction that, when viewed in the axial direction of the combustion chamber, extends to both sides of the ignition portion that clamps the spark plug.

[0030] (6) The hydrogen engine according to any one of (1) to (5) above,

[0031] The accumulator chamber demarcation section forms part of the cylinder head that demarcates the combustion chamber.

[0032] (7) The hydrogen engine according to any one of (1) to (5) above,

[0033] The accumulator chamber demarcation section is configured as a separate component from the cylinder head that demarcates the combustion chamber.

[0034] (8) The hydrogen engine according to any one of (1) to (7) above,

[0035] The connecting hole is formed such that its total flow path cross-sectional area is smaller than that of the accumulator chamber, thus becoming a throttling section relative to the accumulator chamber.

[0036] (9) The hydrogen engine according to (8) above,

[0037] The connecting hole is formed such that its total flow path cross-sectional area is larger than the flow path cross-sectional area at the throttling section of the injector, so that when hydrogen is injected from the injector, the flow rate of hydrogen at the throttling section of the injector becomes a predetermined flow rate.

[0038] (10) The hydrogen engine according to any one of (1) to (9) above,

[0039] The accumulator chamber is formed with the same axis as the nozzle of the injector.

[0040] (11) The hydrogen engine according to any one of (1) to (10) above,

[0041] It also has a check valve located in the accumulator chamber.

[0042] The check valve allows fluid to flow from the injector to the connecting hole and prevents fluid from flowing from the connecting hole to the injector.

[0043] (12) The hydrogen engine described in (11) above,

[0044] It also has a force-applying component that applies force to the check valve toward the nozzle of the injector.

[0045] The force-applying component is fixed to the injector.

[0046] Invention Effects

[0047] According to this disclosure, the possibility of damage to the hydrogen injector due to heat from the combustion chamber can be reduced. Attached Figure Description

[0048] Figure 1 This is a partial cross-sectional view of the engine according to the first embodiment, shown in a schematic manner.

[0049] Figure 2 It is a partial bottom view that roughly shows the bottom surface of the cylinder head.

[0050] Figure 3 This is an enlarged view of the cylinder head portion surrounding the spark plugs and injectors. Figure 2A sectional view taken during observation of line III-III.

[0051] Figure 4 It is a cross-sectional view showing an enlarged portion of the cylinder head surrounding the injector.

[0052] Figure 5 This is an enlarged view of a portion of the cylinder head around the injector involved in a variant example. Figure 4 The same sectional view.

[0053] Figure 6 This is an enlarged view of a portion of the cylinder head around the injector involved in another variation. Figure 4 The same sectional view.

[0054] Figure 7 This is an enlarged view of a portion of the cylinder head surrounding the injector according to the second embodiment. Figure 4 The same sectional view.

[0055] Figure 8 This is an enlarged view of a portion of the cylinder head surrounding the injector according to the third embodiment. Figure 4 The same sectional view.

[0056] Figure 9 It is a diagram that roughly illustrates the operation of the check valve.

[0057] Figure 10 It is a diagram that roughly shows the structure around the accumulator.

[0058] Figure 11 It is a diagram that roughly shows the structure around the accumulator.

[0059] Figure 12 It is a diagram that roughly shows the structure around the accumulator.

[0060] Figure 13 This is an enlarged view of the cylinder head surrounding the injector when the accumulator demarcation member is installed. Figure 4 The same sectional view.

[0061] Figure 14 It is a general illustration of the structure surrounding the accumulator chamber. Figure 12 The same diagram. Detailed Implementation

[0062] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. It should be noted that in the following description, the same reference numerals are used to refer to the same constituent elements.

[0063] First Implementation Method

[0064] <Overall Structure of the Engine>

[0065] First, refer to Figure 1 and Figure 2 The overall structure of the hydrogen engine (hereinafter also referred to as "engine") 1 according to the first embodiment will be described. In the hydrogen engine, hydrogen gas is directly injected into the combustion chamber as fuel. Figure 1 This is a partial cross-sectional view of the engine 1 according to this embodiment, shown in a schematic manner. Figure 1 As shown, engine 1 includes cylinder block 2, cylinder head 3, piston 4, and connecting rod 5.

[0066] The cylinder block 2 has a plurality of cylinders 6 arranged in an array. The cylinder head 3 is configured to abut against the cylinder block 2 at the abutment plane A and is configured to block one end of the cylinders 6 formed in the cylinder block 2. The cylinder block 2 and the cylinder head 3 are made of metals such as aluminum alloy and cast iron.

[0067] Piston 4 is configured to reciprocate within cylinder 6, which is formed within cylinder block 2. Piston 4 is connected to connecting rod 5 via piston pin. Connecting rod 5 is connected to crankshaft (not shown) via crankshaft pin. Connecting rod 5 functions to convert the reciprocating motion of piston 4 into rotational motion of crankshaft. Furthermore, combustion chamber 7, for burning a mixture of air and hydrogen, is defined by the walls of cylinder 6 in cylinder block 2, cylinder head 3, and piston 4. Within combustion chamber 7, the mixture of air and hydrogen... Figure 1 The direction indicated by the middle arrow generates a swirling flow of the mixed gas.

[0068] Figure 2 This is a partial bottom view that schematically shows the bottom surface of the cylinder head 3. In particular, Figure 2 A portion of the cylinder head 3, located at the position blocking one of the cylinders 6, is shown in a schematic diagram. Additionally, in Figure 2 The injector 51, accumulator 61 and connecting hole 62, which will be described later, are depicted in the text. However, since they are located inside the cylinder head 3, they are not visible from the bottom side of the cylinder head 3. They are depicted for ease of understanding.

[0069] like Figure 1 and Figure 2 As shown, an intake port 11 and an exhaust port 12 are formed in the cylinder head 3. The intake port 11 faces the combustion chamber 7 and communicates with the combustion chamber 7 through an intake opening 13 formed in the cylinder head 3. Similarly, the exhaust port 12 faces the combustion chamber 7 and communicates with the combustion chamber 7 through an exhaust opening 14 formed in the cylinder head 3.

[0070] like Figure 2As shown, in this embodiment, each combustion chamber 7 is provided with two intake openings 13 and two exhaust openings 14. The two intake openings 13 are arranged in the same direction as the arrangement direction of the plurality of cylinders 6 (hereinafter also referred to as the "cylinder arrangement direction"). Similarly, the two exhaust openings 14 are arranged in the same direction as the cylinder arrangement direction. With respect to the central plane C that passes through the center of each cylinder 6 and extends in the cylinder arrangement direction, two intake openings 13 are provided on one side and two exhaust openings 14 are provided on the other side.

[0071] like Figure 1 As shown, the cylinder head 3 is formed such that the upper surface of the combustion chamber 7 has two inclined surfaces: an intake-side inclined surface 17 and an exhaust-side inclined surface 18. The intake-side inclined surface 17 is formed such that its height (the length of the cylinder 6 along the Z-direction from the abutment plane A) gradually increases from the edge of the intake opening side towards the central plane C. The exhaust-side inclined surface 18 is formed such that its height gradually increases from the edge of the exhaust opening side towards the central plane C. Therefore, the upper surface of the combustion chamber 7 is inclined such that it is highest at the central plane C.

[0072] In addition, the cylinder head 3 is provided with an intake valve 21 for opening and closing the intake opening 13, an exhaust valve 31 for opening and closing the exhaust opening 14, a spark plug 41 for igniting the mixture in the combustion chamber 7, and an injector 51 for directly injecting hydrogen into the combustion chamber 7.

[0073] The intake valve 21 includes a valve stem 22 and a valve core 23 fixed to one end of the valve stem 22. The intake valve 21 is disposed within the cylinder head 3 in such a way that it can slide in the direction in which the valve stem 22 extends, i.e., in the axial direction of the intake valve 21. The intake valve 21 is lifted in its axial direction by an intake valve mechanism (not shown).

[0074] Similarly, the exhaust valve 31 includes a valve stem 32 and a valve core 33 fixed to one end of the valve stem 32. The exhaust valve 31 is disposed within the cylinder head 3 in such a way that it can slide in the direction in which the valve stem 32 extends, i.e., in the axial direction of the exhaust valve 31. The exhaust valve 31 is lifted in its axial direction by an exhaust valve mechanism (not shown).

[0075] The spark plug 41 is mounted on the cylinder head 3 such that, when viewed in the Z direction (i.e., the axis of the combustion chamber 7) along the axis of the cylinder 6, it is located approximately at the center of the combustion chamber 7 on its upper surface. Therefore, the spark plug 41 is configured to be exposed to the combustion chamber 7. The spark plug 41 has an electrode 42 at its end that functions as an ignition part for igniting the air-fuel mixture. Thus, when viewed in the Z direction along the axis of the cylinder 6, the electrode 42 of the spark plug 41 is located approximately at the center of the combustion chamber 7 near its upper surface.

[0076] <Structure around the injector>

[0077] Next, besides Figure 1 and Figure 2 In addition, refer to Figure 3 and Figure 4 The structure of the cylinder head 3 surrounding the injector 51 will be explained. Figure 3 This is an enlarged view of a portion of the cylinder head 3 surrounding the spark plug 41 and injector 51, along... Figure 2 A sectional view taken when observing line III-III. Additionally, Figure 4 This is an enlarged view of the cylinder head 3 surrounding the injector 51. Figure 3 An enlarged sectional view of a portion. It should be noted that... Figure 4 In the image, only the top of the injector 51 is depicted in a cross-section.

[0078] like Figure 2 As shown, the injector 51 is positioned closer to the intake opening side than the central plane C. In particular, in this embodiment, the injector 51 is positioned between the two intake openings 13 and near the outer periphery of the cylinder 6 to inject hydrogen. It should be noted that the injector 51 may not be positioned between the intake openings 13, or it may be positioned between the exhaust openings 14 and near the center of the combustion chamber 7 on the cylinder head 3.

[0079] In addition, such as Figure 4 As shown, the injector 51 has a nozzle 52 at its top for injecting hydrogen. The nozzle 52 is formed so that its axis is the same as the axis of the injector 51 (in the figure, both the axis of the injector 51 and the axis of the nozzle 52 are represented by X). In this embodiment, the nozzle 52 is formed such that the flow path cross-sectional area in the section perpendicular to the main flow direction of the hydrogen is minimized in the injector 51. Therefore, in this embodiment, the nozzle 52 functions as a throttling section for the flow of hydrogen in the injector 51. It should be noted that the nozzle 52 may also be formed such that its axis faces a direction different from the axis X of the injector 51. Alternatively, the injector 51 may also be formed such that the flow path cross-sectional area around the valve core of the needle valve or the like that opening and closing the nozzle 52 is minimized in the injector 51. In this case, the area around the valve core of the needle valve or the like functions as a throttling section for the flow of hydrogen.

[0080] In addition, such as Figure 3 and Figure 4As shown, the injector 51 is disposed within a bore 45 formed in the cylinder head 3. The bore 45 is open to the outside of the cylinder head 3 in such a way that the injector 51 can be inserted. The bore 45 is formed with a cross-sectional shape perpendicular to its axial direction that is approximately the same as or slightly larger than the cross-sectional shape of the injector 51. In addition, the portion of the bore 45 having a cross-sectional shape (circular in this embodiment) that is approximately the same as the cylindrical portion 53 with a circular cross-section that is thinner than other portions on the top side of the injector 51 has an axial length that is longer than the axial length of the cylindrical portion 53. Furthermore, the injector 51 is fixed within the bore 45 by any method, such as supporting its rear portion with another component fixed to the cylinder head 3.

[0081] In addition, such as Figure 3 and Figure 4 As shown, a pressure accumulator 61, a connecting hole 62, and a pressure accumulator demarcation section 63 defining these pressure accumulators 61 and connecting holes 62 are provided between the injector 51 and the combustion chamber 7. Figure 4 As shown, the accumulator chamber 61 communicates with the nozzle 52 of the injector 51 and with the connecting hole 62. Furthermore, the connecting hole 62 communicates with the accumulator chamber 61 and with the combustion chamber 7. In particular, in this embodiment, the connecting hole 62 is formed as an opening on the end face of the accumulator chamber 61 opposite to the injector 51 side. However, the connecting hole 62 may also be formed as an annular side opening of the accumulator chamber 61 in addition to the end face opposite to the injector 51 side.

[0082] The accumulator 61 is formed with the same axis as the axis X of the nozzle 52 of the injector 51. Therefore, the annular sidewalls defining the accumulator 61 can be suppressed from becoming a flow path resistance for the hydrogen ejected from the injector 51. Furthermore, in this embodiment, the accumulator 61 has a cross-sectional shape in a section perpendicular to the axis X that is approximately the same as the cross-sectional shape of the top of the injector 51 where the nozzle 52 is located (i.e., the cross-sectional shape of the cylindrical portion 53). Therefore, in this embodiment, the accumulator 61 has a circular cross-sectional shape. In addition, the flow path cross-sectional area of ​​the accumulator 61 (i.e., the cross-sectional area in a section perpendicular to the axis X) is approximately the same as the cross-sectional area of ​​the top of the injector 51. Therefore, the accumulator 61 has a flow path cross-sectional area larger than the flow path cross-sectional area of ​​the nozzle 52 by an amount corresponding to the thickness of the wall portion surrounding the nozzle 52 of the injector 51. In this embodiment, the accumulator 61 is formed within the bore 45 of the cylinder head 3, and is formed such that the length in the axial direction of the portion of the bore 45 having a cross-sectional shape substantially the same as that of the cylindrical portion 53 of the injector 51 is longer than the length in the X-direction of the axial direction of the cylindrical portion 53. It should be noted that the accumulator 61 may also have a cross-sectional shape other than a circle, such as a polygonal shape or an elliptical shape.

[0083] It should be noted that the accumulator 61 may also be formed with an axis different from the axis X of the nozzle 52. In addition, the accumulator 61 may also have a cross-sectional shape different from the cross-sectional shape of the top of the injector 51. Furthermore, the flow path cross-sectional area of ​​the accumulator 61 may be larger or smaller than the cross-sectional area of ​​the top of the injector 51.

[0084] In this embodiment, two connecting holes 62 are provided. Specifically, in this embodiment, from... Figure 2 As can be seen, the connecting holes 62 are arranged side by side when viewed along the Z-axis of the cylinder 6. Furthermore, the cross-sectional shape of the connecting holes 62 in a section perpendicular to the main flow direction of hydrogen is approximately circular. In addition, in this embodiment, the two connecting holes 62 are formed so that their cross-sectional shapes are identical, and therefore their flow path cross-sectional areas are identical. It should be noted that the connecting holes 62 may also have cross-sectional shapes other than circular, such as polygonal or elliptical shapes.

[0085] Furthermore, the two connecting holes 62 are configured such that their total flow path cross-sectional area is smaller than that of the accumulator chamber 61. As a result, the connecting holes 62 function as throttling points in the flow of hydrogen relative to the accumulator chamber 61.

[0086] In addition, the two connecting holes 62 are configured such that their total flow path cross-sectional area is larger than the flow path cross-sectional area at the throttling section of the injector 51, so that when hydrogen is injected from the injector 51, the flow velocity of the hydrogen at the throttling section (orifice 52 in this embodiment) of the injector 51 becomes a predetermined flow velocity (sonic speed in this embodiment). Specifically, for example, the total flow path cross-sectional area of ​​the two connecting holes 62 is, for example, more than 1.75 times the flow path cross-sectional area at the throttling section of the injector 51. In this way, by achieving a predetermined flow velocity (e.g., sonic speed) when hydrogen is injected from the injector 51, the amount of hydrogen supplied to the combustion chamber 7 can be adjusted based solely on the time the injector 51 is opened, thereby easily controlling the amount of hydrogen supplied to the combustion chamber 7.

[0087] In addition, in this embodiment, such as Figure 2 and Figure 4 As shown, the two connecting holes 62 are each formed with an axis Y at an angle relative to the axis X of the nozzle 52 of the injector 51. In particular, in this embodiment, as... Figure 4 As shown, the axis Y of the two connecting holes 62 extends obliquely toward the piston 4 side (in the direction from the cylinder head 3 to the cylinder block 2 in the direction of hydrogen injection from the nozzle 52 of the injector 51, relative to the axis X of the nozzle 52 of the injector 51. That is, as Figure 4As shown, the axis Y of the two connecting holes 62 extends obliquely relative to the axis X of the injector 51 in a cross section containing the axis Z of the cylinder 6 and the axis X of the injector 51. The oblique angle α at this time is, for example, 5-30°, 7-20° or 10-15°.

[0088] Moreover, in this embodiment, such as Figure 2 As shown, the axis Y of the two connecting holes 62 extends obliquely relative to the axis X of the nozzle 52 of the injector 51, such that it is separated from the electrode 42 of the spark plug 41. That is, as Figure 2 As shown, when viewed along the Z-axis of the cylinder 6, the Y-axis of each of the two connecting holes 62 extends obliquely relative to the X-axis of the nozzle 52 extending through the spark plug 41. The oblique angle β at this time is, for example, 5–45°, 7–35°, or 10–20°. Furthermore, as... Figure 2 As shown, when viewed along the Z-axis of the cylinder 6, the axes Y of the two connecting holes 62 extend in opposite directions relative to the axis X of the nozzle 52. Therefore, in this embodiment, as... Figure 2 As shown, when viewed in the direction of the axis Y of the two connecting holes 62 along the axis Z of the cylinder 6, the axis Y extends in the direction that expands to both sides of the electrode 42 that clamps the spark plug 41.

[0089] The accumulator chamber demarcation section 63 is located around the injector 51, the accumulator chamber 61, and the connecting hole 62. In particular, in this embodiment, the accumulator chamber demarcation section 63 is configured as part of the cylinder head 3. Therefore, the accumulator chamber demarcation section 63 is a portion of the cylinder head 3 located around the accumulator chamber 61 and the connecting hole 62. Therefore, the accumulator chamber demarcation section 63 is formed of the same material as the cylinder head 3 (i.e., the combustion chamber wall that demarcates the combustion chamber 7). Therefore, the accumulator chamber demarcation section 63 has the same thermal conductivity as the cylinder head 3. On the other hand, the cylinder head 3 and the injector 51 are formed separately, thereby the accumulator chamber demarcation section 63 is formed separately from the injector 51.

[0090] In this hydrogen engine 1, when hydrogen is injected from the nozzle 52 of the injector 51, the injected hydrogen passes through the accumulator 61 and the connecting hole 62 and is injected into the combustion chamber 7 through the connecting hole 62. As described above, the hydrogen is injected from the nozzle 52 at a speed that is the speed of sound at the throttling section of the injector 51, and then flows through the accumulator 61 and the connecting hole 62 at a speed slower than the speed of sound before being injected into the combustion chamber 7. Furthermore, when injected from the connecting hole 62, the hydrogen is mainly injected into the combustion chamber 7 in the direction of the axis Y of the connecting hole 62.

[0091] <Effect>

[0092] Furthermore, as mentioned above, hydrogen burns rapidly, has a low minimum ignition energy, and a wide flammability range when mixed with air. Consequently, the quenching distance is short, and the flame reaches near the wall of combustion chamber 7. Therefore, the temperature of components exposed to combustion chamber 7 is more likely to rise. In addition, due to the low minimum ignition energy of hydrogen, premature ignition (early ignition) and other abnormal combustion are prone to occur. In the event of such abnormal combustion, components exposed to combustion chamber 7 will be exposed to high temperatures.

[0093] In contrast, in this embodiment, the accumulator 63, located between the injector 51 and the combustion chamber 7, is part of the cylinder head 3 and has the same thermal conductivity as the cylinder head 3. Therefore, it is cooled together with the cylinder head 3 by cooling water or the like flowing within the cylinder head 3. Furthermore, an accumulator 61 and a connecting hole 62 are provided between the injector 51 and the combustion chamber 7. Therefore, the injector 51 is positioned at a location retracted from the other walls of the combustion chamber 7. Consequently, the flame within the combustion chamber 7 is less likely to reach the tip of the injector 51. This prevents the injector 51 from being stably maintained at a high temperature and thus from being damaged, and also prevents damage to the injector 51 in cases such as premature ignition.

[0094] Furthermore, in this embodiment, the total flow path cross-sectional area of ​​the connecting hole 62 is smaller than that of the accumulator chamber 61. Thus, due to the smaller flow path cross-sectional area of ​​the connecting hole 62, the flame in the combustion chamber 7 is less likely to reach the accumulator chamber 61. Therefore, this also helps to prevent the injector 51 from maintaining a high temperature and prevents damage to the injector 51.

[0095] Furthermore, in this embodiment, the connecting hole 62 has an axis Y with an arbitrary angle relative to the axis X of the nozzle 52 of the injector 51. Therefore, the injector 51 can be positioned at a location retracted from the other walls defining the combustion chamber 7, and hydrogen can be injected in a desired direction determined by the axis Y, other than the axis X direction of the nozzle 52 of the injector 51. Additionally, since the stoichiometric air-fuel ratio of the hydrogen mixture is low, a large amount of hydrogen needs to be supplied to the combustion chamber 7. Therefore, the cross-sectional area of ​​the nozzle 52 of the injector 51 is preferably as large as possible, making it difficult to align the orientation and shape of the nozzle 52 with the optimal injection direction. In contrast, in this embodiment, since the injection into the combustion chamber 7 is performed through the connecting hole 62 in the optimal injection direction, the nozzle 52 of the injector 51 can be formed to extend in the axis X direction of the injector 51, allowing for a large flow path cross-sectional area of ​​the injector 51.

[0096] Furthermore, in this embodiment, the axis Y of the connecting hole 62 is inclined at an angle α toward the piston 4 relative to the axis X of the nozzle 52 of the injector 51 (in... Figure 1 and Figure 4The cylinder head 3 extends at an angle (downwards). Therefore, it can prevent hydrogen injected into the combustion chamber 7 through the connecting hole 62 from coming into contact with the high-temperature uneven parts on the lower surface of the cylinder head 3 in the early stage, thereby suppressing abnormal combustion such as premature ignition.

[0097] Furthermore, in this embodiment, the axis Y of the connecting hole 62 extends obliquely at an angle β relative to the axis X of the nozzle 52 of the injector 51, thus moving away from the electrode 42 of the spark plug 41. Therefore, the concentration of the air-fuel mixture near the electrode 42 of the spark plug 41, which becomes hot, can be suppressed, thereby preventing premature ignition near the spark plug 41. Additionally, in this embodiment, the axes Y of the two connecting holes 62 extend laterally in a direction that sandwiches the electrode 42 of the spark plug 41. Therefore, while suppressing an excessively high concentration of the air-fuel mixture near the electrode 42 of the spark plug 41, a certain level of air-fuel mixture can be formed around the electrode 42 of the spark plug 41, thereby enabling ignition of the air-fuel mixture using the spark plug 41.

[0098] <Variation Example>

[0099] In the above embodiment, the engine 1 is provided with two connecting holes 62. However, one or more connecting holes are sufficient, or multiple connecting holes may be provided. Therefore, it is sufficient to provide one or more connecting holes 62 in the engine 1. Thus, the engine 1 may also have only one connecting hole 62, or it may have three or more connecting holes 62.

[0100] In addition, in the above embodiment, each connecting hole 62 is formed such that its axis Y extends at an angle relative to the axis X of the nozzle 52 of the injector 51. However, all or part of one or more connecting holes 62 may also be formed such that its axis Y extends in the same direction as the axis X of the nozzle 52. Furthermore, at least a portion of the connecting holes 62 may also extend its axis Y relative to the axis X of the nozzle 52 in a manner that does not depart from the electrode 42 of the spark plug 41.

[0101] Furthermore, in the above embodiment, the axes Y of the two connecting holes 62 are inclined at the same angle α towards the axis Z of the cylinder 6 relative to the axis X of the nozzle 52. However, the axes Y of the two connecting holes 62 can also be inclined at different angles towards the axis Z of the cylinder 6 relative to the axis X of the nozzle 52 (i.e., in...). Figure 4 The axis Y of the two connecting holes 62 is tilted at the same angle β in opposite directions relative to the axis X of the nozzle 52 when viewed in the Z direction of the cylinder 6. However, when viewed in the Z direction of the cylinder 6, the axis Y of the two connecting holes 62 may also be tilted at the same angle in the same direction relative to the axis X of the nozzle 52 (i.e., in...). Figure 2 (They can all be tilted upwards or downwards). Alternatively, when viewed along the axis Y of the two connecting holes 62 in the direction of the axis Z of the cylinder 6, they can also be tilted at different angles relative to the axis X of the nozzle 52 in opposite or the same directions.

[0102] Figure 5 This is an enlarged view of a portion of the cylinder head 3 surrounding the injector 51 in a modified example. Figure 4 The same sectional view. In Figure 5 In the example shown, engine 1 has four connecting holes 62. (As shown...) Figure 5 As shown, two connecting holes 62 are arranged along the Z-axis of cylinder 6, and these connecting holes 62 are inclined at different angles relative to the X-axis of nozzle 52. In particular, in this modified example, the connecting holes 62 located on the side opposite to piston 4 (the upper side in the figure) have a smaller angle of inclination than the connecting holes 62 located on the side of piston 4 (the lower side in the figure). Furthermore, in this modified example, when viewed along the Z-axis of cylinder 6, each of the two connecting holes 62 is inclined at the same angle β in opposite directions relative to the X-axis of nozzle 52. By forming the connecting holes 62 in this way, hydrogen gas can be diffused extensively into the combustion chamber 7.

[0103] Figure 6 This is an enlarged view of a portion of the cylinder head 3 surrounding the injector 51, as described in another variation. Figure 4 The same sectional view. In Figure 6 In the example shown, only the connecting hole 62 is provided in the engine 1. Furthermore, the connecting hole 62 is formed such that its axis Y extends along the axis X of the nozzle 52 of the injector 51. By making the connecting hole 62 in this structure, the forming and machining of the connecting hole 62 becomes easier.

[0104] Furthermore, in the above embodiment, the flow path cross-sectional area of ​​the accumulator 61 is formed to be larger than the flow path cross-sectional area of ​​the nozzle 52 of the injector 51. However, the flow path cross-sectional area of ​​the accumulator 61 may also be formed to be approximately the same as the flow path cross-sectional area of ​​the nozzle 52 of the injector 51. In addition, in the above embodiment, the total flow path cross-sectional area of ​​the plurality of connecting holes 62 is formed to be smaller than the flow path cross-sectional area of ​​the accumulator 61. However, when a plurality of connecting holes 62 are provided, the plurality of connecting holes 62 may also be formed to have a total flow path cross-sectional area approximately the same as the flow path cross-sectional area of ​​the accumulator 61. Furthermore, in this embodiment, the total flow path cross-sectional area of ​​the connecting holes 62 is formed to be larger than the flow path cross-sectional area at the throttling section of the injector 51. However, the connecting holes 62 may also be formed to have a flow path cross-sectional area approximately the same as the flow path cross-sectional area at the throttling section of the injector 51.

[0105] Furthermore, in the above embodiment, the hydrogen engine 1 only has an injector 51 that directly injects hydrogen into the combustion chamber 7. However, the hydrogen engine 1 may also have an injector that injects hydrogen or other fuel into the intake passage such as the air intake 11, in addition to the injector 51 that directly injects hydrogen into the combustion chamber 7.

[0106] Second Implementation Method

[0107] Next, refer to Figure 7 The hydrogen engine 1 according to the second embodiment will be described. The structure of the hydrogen engine 1 according to the second embodiment is basically the same as that of the hydrogen engine 1 according to the first embodiment. Therefore, the following description will focus on the parts that are different in structure from the hydrogen engine 1 according to the first embodiment.

[0108] Figure 7 This is an enlarged view of a portion of the cylinder head 3 surrounding the injector 51 according to the second embodiment. Figure 4 The same sectional view. (e.g.) Figure 7 As shown, the bore 45 formed in the cylinder head 3 has a cross-sectional shape that is perpendicular to its axial direction and larger than the cross-sectional shape of the cylindrical portion 53 of the injector 51. Furthermore, in this embodiment, a pressure accumulator defining member 63' is provided near the top end of the cylindrical portion 53 of the injector 51, between the inner surface of the bore 45 and the outer surface of the cylindrical portion 53. The pressure accumulator defining member 63' is provided between the injector 51 and the combustion chamber 7, and functions as a pressure accumulator defining portion that defines the pressure accumulator 61 and the connecting hole 62. Therefore, in this embodiment, the pressure accumulator defining portion is configured as a separate component from the cylinder head 3 that defines the combustion chamber 7.

[0109] In this embodiment, the accumulator chamber demarcation member 63' is formed of the same material as the cylinder head 3, i.e., a metal such as aluminum alloy or cast iron. Therefore, in this embodiment, the accumulator chamber demarcation member 63' has the same thermal conductivity and corrosion resistance as the cylinder head 3. However, the accumulator chamber demarcation member 63' may also be formed of another material with thermal conductivity higher than that of the cylinder head 3 used as a combustion chamber wall. In addition, the accumulator chamber demarcation member 63' may also be formed of another material with corrosion resistance higher than that of the cylinder head 3. Specifically, the accumulator chamber demarcation member 63' may also be formed of, for example, beryllium copper.

[0110] like Figure 7As shown, the accumulator chamber defining member 63' has a hole 64 for inserting the injector 51. The hole 64 is formed with a cross-sectional shape perpendicular to its axial direction that is approximately the same as or slightly larger than the cross-sectional shape of the cylindrical portion 53 of the injector 51. Furthermore, the accumulator chamber defining member 63' is pressed into the hole 45 of the cylinder head 3, and is configured such that when the injector 51 is inserted, the tip of the injector 51 does not reach the bottom surface of the hole 64 of the accumulator chamber defining member 63'. Thus, an accumulator chamber 61 is formed between the tip of the injector 51 and the bottom surface of the hole 64 of the accumulator chamber defining member 63'.

[0111] According to this embodiment, since the accumulator chamber defining portion is configured as a separate component from the cylinder head 3, it is easier to form the connecting hole 62, thereby improving the machining accuracy of the connecting hole 62. In addition, the accumulator chamber defining portion can be formed using a material with higher thermal conductivity and corrosion resistance than the cylinder head 3, thereby improving the cooling performance around the tip of the injector 51 and suppressing deformation and blockage of the connecting hole 62 caused by corrosion.

[0112] Third Implementation Method

[0113] Next, refer to Figures 8-12 The hydrogen engine 1 according to the third embodiment will be described. The structure of the hydrogen engine 1 according to the third embodiment is basically the same as that of the hydrogen engine 1 according to the first embodiment. Therefore, the following description will focus on the parts that are different in structure from the hydrogen engine 1 according to the first embodiment.

[0114] Figure 8 This is an enlarged view of the portion of the cylinder head 3 surrounding the injector 51 according to the third embodiment. Figure 4 The same sectional view. (e.g.) Figure 8 As shown, the engine 1 according to this embodiment has a spherical check valve 65 and a coil spring 66 that applies force to the check valve 65 toward the nozzle 52 of the injector 51.

[0115] A check valve 65 and a coil spring 66 are disposed within the accumulator chamber 61. The check valve 65 and the coil spring 66 are configured such that their axes coincide with the axis X of the nozzle 52 of the injector 51. The coil spring 66 is disposed on the end face of the opening of the communication hole 62 in the accumulator chamber 61. In addition, the check valve 65 is disposed between the coil spring 66 and the injector 51.

[0116] Figure 9 This is a diagram that roughly illustrates the operation of the check valve 65. Figure 9 (A) illustrates a combustion state where no hydrogen is injected from the injector 51 and no mixture is generated in the combustion chamber 7. Additionally, Figure 9(B) shows the state where hydrogen gas is being ejected from injector 51. In addition, Figure 9 (C) shows the combustion state in which a mixture is generated in the combustion chamber 7.

[0117] like Figure 9 As shown in (A), when no hydrogen is injected from the injector 51 and no combustion of the mixture is generated in the combustion chamber 7, the check valve 65 is forced by the coil spring 66 against the nozzle 52 of the injector 51, closing the nozzle 52. Furthermore, as... Figure 9 As shown in (B), when hydrogen is injected from the injector 51, the check valve 65 opens due to the pressure of the hydrogen. In other words, when hydrogen is injected from the nozzle 52, the coil spring 66 exerts a force on the check valve 65 towards the nozzle 52, causing the check valve 65 to open due to the pressure of the hydrogen. As a result, hydrogen flows from the injector 51 toward the connecting hole 62. On the other hand, as... Figure 9 As shown in (C), when a mixture is being burned in the combustion chamber 7, the check valve 65 is closed by the pressure inside the combustion chamber 7. As a result, the flow of gas generated by combustion in the combustion chamber 7 into the nozzle 52 of the injector 51 via the connecting hole 62 and the accumulator 61 can be suppressed. That is, in this embodiment, the check valve 65 is configured to allow the flow of hydrogen (fluid) from the injector 51 to the connecting hole 62 and to prohibit the flow of combustion gas (fluid) from the connecting hole 62 to the injector 51.

[0118] According to this embodiment, the check valve 65 prevents combustion gases from flowing back from the combustion chamber 7 through the nozzle 52 into the injector 51. Therefore, the durability of the injector 51 can be improved.

[0119] It should be noted that in the third embodiment described above, the check valve 65 is a spherical valve, and a coil spring 66 is used as the force-applying member that applies force to the check valve 65 toward the nozzle 52 of the injector 51. However, as the check valve 65, any valve shape other than a spherical valve, such as a plate valve or a cylindrical valve, can be used. In addition, as the force-applying member, any elastic member such as a disc spring or a leaf spring can be used.

[0120] Figures 10-12 This is a diagram that schematically shows the structure surrounding the accumulator chamber 61. In particular, Figures 10-12 The structure around the accumulator 61 is shown, with the check valve 65 and the force-applying components having different structures from each other.

[0121] Figure 10 An example is shown where a plate valve 65a is used as a check valve and a conical helical spring 66a is used as a force-applying component. Figure 10 (A) shows a cross-sectional view around the accumulator chamber 61. Figure 10 (B) shows along Figure 10(A) is a cross-sectional view of the pressure accumulator 61 as observed by line BB. Figure 10 As shown in (B), the plate valve 65a is configured such that its outer periphery partially contacts the inner surface of the accumulator compartment 63. This restricts the movement of the plate valve 65a in a direction perpendicular to the main flow direction of hydrogen. Furthermore, the plate valve 65a is configured such that its outer periphery partially separates from the inner surface of the accumulator compartment 63. This allows hydrogen to flow between the plate valve 65a and the inner surface of the accumulator compartment 63.

[0122] in addition, Figure 11 An example is shown where a cylindrical valve 65b is used as a check valve and a disc spring 66b is used as a force-applying component. Figure 11 (A) shows a cross-sectional view around the accumulator chamber 61. Figure 11 (B) shows along Figure 11 (A) is a cross-sectional view of the pressure accumulator 61 observed along line BB. Additionally, Figure 11 (C) is a top view of the coil spring 66b. For example... Figure 11 As shown in (C), the coil spring 66b has an annular portion 67 that contacts the inner surface of the accumulator chamber demarcation portion 63 and is placed on the end face of the opening of the communication hole 62 of the accumulator chamber 61, and a plurality of elastic portions 68 extending inward from the annular portion 67. The plurality of elastic portions 68 exert force on the cylindrical valve 65b and are arranged circumferentially separated from each other, through which hydrogen gas flows.

[0123] and, Figure 12 An example is shown where a ball valve 65 is used as a check valve and a disc spring 66b is used as a force-applying component. Figure 12 (A) shows a cross-sectional view around the accumulator chamber 61. Figure 12 (B) is a top view of the coil spring 66b.

[0124] Furthermore, in the third embodiment described above, the accumulator defining portion 63 is formed as part of the cylinder head 3 in the same manner as in the first embodiment. However, the accumulator defining portion can also be configured as a separate accumulator defining member 63' from the cylinder head 3, similar to the second embodiment. Figure 13 This is an enlarged view of the cylinder head 3 surrounding the injector 51 when the accumulator chamber demarcation member 63' is provided. Figure 4 The same sectional view. In Figure 13 In the example shown, the accumulator defining member 63' is disposed in the bore 45 of the cylinder head 3, and a spherical check valve 65 and a coil spring 66 are disposed in the accumulator 61 defined by the accumulator defining member 63'.

[0125] Furthermore, in the third embodiment described above, the helical spring 66, serving as a force-applying component, is mounted on the end face of the opening of the communication hole 62 in the accumulator 61. However, the force-applying component may also be fixed to the injector 51. Figure 14 This is a schematic representation of the structure surrounding the accumulator chamber 61. Figure 12 The same diagram. (As shown) Figure 14 As shown, the force-applying member 66' has an annular portion 67' formed in a cylindrical shape and a plurality of elastic portions 68 extending inward from the end of the annular portion 67' opposite to the injector 51 side. The end of the annular portion 67' on the injector 51 side is pressed into the outer surface of the injector 51, thereby fixing it to the injector 51. Therefore, in Figure 14 In the example shown, the force-applying component 66' is fixed to the injector 51. By fixing the force-applying component to the injector 51 in this way, it is easy to assemble the check valve and the force-applying component.

[0126] The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments, and various modifications and variations can be implemented within the scope of the claims.

[0127] Explanation of reference numerals in the attached figures

[0128] 1. Hydrogen engine

[0129] 2 Cylinder Block

[0130] 3. Cylinder head

[0131] 6 cylinders

[0132] 7 Combustion Chamber

[0133] 41 Spark plugs

[0134] 42 electrodes

[0135] 45 Hole Section

[0136] 51 Injector

[0137] 52 nozzles

[0138] 61. Accumulator

[0139] 62 connecting holes

[0140] 63. Accumulator chamber designation section.

Claims

1. A hydrogen engine that supplies hydrogen gas as fuel to a combustion chamber, wherein, have: The injector sprays hydrogen gas. The accumulator chamber is connected to the nozzle of the injector; The connecting hole communicates with the accumulator chamber and the combustion chamber; and A pressure accumulator defining section is provided between the injector and the combustion chamber, defining the pressure accumulator chamber and the communicating hole. The accumulator chamber demarcation section is formed separately from the injector and has thermal conductivity exceeding that of the combustion chamber wall that demarcates the combustion chamber. The accumulator chamber demarcation section forms part of the cylinder head that demarcates the combustion chamber. The connecting hole is formed such that its total flow path cross-sectional area is smaller than that of the accumulator chamber, thus acting as a throttling section relative to the accumulator chamber. The connecting hole is formed such that its total flow path cross-sectional area is larger than the flow path cross-sectional area at the throttling section of the injector, so that when hydrogen is injected from the injector, the flow rate of hydrogen at the throttling section of the injector becomes a predetermined flow rate.

2. The hydrogen engine according to claim 1, There is one or more connecting holes. At least one of the connecting holes is formed as an axis having an angle relative to the axis of the nozzle of the injector.

3. The hydrogen engine according to claim 2, It also has a piston that reciprocates within a cylinder that defines the combustion chamber. At least one of the connecting holes is formed as having an axis that extends obliquely toward the piston side in the injection direction relative to the axis of the nozzle of the injector.

4. The hydrogen engine according to claim 2 or 3, It also includes a spark plug configured to be exposed to the combustion chamber and to ignite the hydrogen-air mixture. At least one of the connecting holes is formed as having an axis that extends obliquely relative to the axis of the injector orifice, such that it is away from the ignition portion of the spark plug.

5. The hydrogen engine according to claim 4, There are two or more connecting holes. At least two of the connecting holes are formed with an axis extending laterally in a direction that, when viewed in the axial direction of the combustion chamber, extends to both sides of the ignition portion that clamps the spark plug.

6. The hydrogen engine according to claim 1 or 2, The accumulator chamber is formed with the same axis as the nozzle of the injector.

7. The hydrogen engine according to claim 1 or 2, It also has a check valve located in the accumulator chamber. The check valve allows fluid to flow from the injector to the connecting hole and prevents fluid from flowing from the connecting hole to the injector.

8. The hydrogen engine according to claim 7, It also has a force-applying component that applies force to the check valve toward the nozzle of the injector. The force-applying component is fixed to the injector.

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