engine

Abstract

The present invention provides an engine that can reduce the number of parts and suppress backfire in the intake port even when using a port injection type injector. [Solution] The hydrogen engine 10 includes an intake port 24 and a port injection injector 34 provided in the cylinder head 16. The intake port 24 includes a common port portion 36, a first port portion 40 and a second port portion 42 branching off from the common port portion 36 at a branching point 38, and a first wall portion 44 and a second wall portion 46 provided on at least one of the first inner surface 48 on the piston top dead center side and the second inner surface 50 on the piston bottom dead center side of the inner circumferential surface of the intake port 24 and extending in the axial direction of the intake port 24. Viewed from the axial direction of the intake port 24, the first wall portion 44 is located on the first port portion 40 side of the branching point 38 and the second wall portion 46 is located on the second port portion 42 side of the branching point 38. The port injection injector 34 is provided near the branching point 38.

Description

Technical Field

[0001] The present invention relates to an engine, and more particularly to an engine having a branched intake port.

Background Art

[0002] An example of this type of conventional art is disclosed in Patent Document 1. The engine disclosed in Patent Document 1 is an engine provided with a combustion chamber, which includes a cylinder head in which an intake port communicating with the combustion chamber is formed, an intake valve having a head portion that opens and closes the open end of the intake port, a partition plate that divides the intake port into a first flow path and a second flow path, and a tumble valve that opens and closes one of the first flow path and the second flow path. The intake port has an upstream common port portion, and a first port portion and a second port portion branched from the common port portion. The partition plate has a common plate portion accommodated in the common port portion, a first plate portion accommodated in the first port portion, and a second plate portion accommodated in the second port portion.

[0003] In such an engine, for example, the tumble valve is operated to a closed position that closes the first flow path, and the first flow path is blocked by the tumble valve, whereby intake air flowing into the intake port from an intake manifold is guided to the combustion chamber via the second flow path of the intake port. That is, by operating the tumble valve to the closed position, most of the intake air passes through the second flow path of the intake port, so that the flow velocity of the intake air can be increased and the intake air can be caused to flow into the combustion chamber.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of Invention

Problem to be Solved by the Invention

[0005] Thus, while Patent Document 1 can increase the flow velocity of intake air and allow it to flow into the combustion chamber, this requires a partition plate and a tumble valve, resulting in a large number of parts. Furthermore, it does not mention anything about suppressing backfire in the intake port even when using a port injection type injector.

[0006] Therefore, the main objective of this invention is to provide an engine that can reduce the number of parts and suppress backfire in the intake port even when using a port injection type injector. [Means for solving the problem]

[0007] To achieve the above objective, an engine is provided comprising a cylinder, a piston reciprocally mounted within the cylinder, a cylinder head mounted on the cylinder, an intake port provided on the cylinder head for drawing air into a combustion chamber defined by the cylinder, piston, and cylinder head, and a port injection injector provided on the cylinder head for injecting gaseous fuel into the intake port, wherein the intake port includes an upstream common port section, a first port section and a second port section branching downstream from the common port section at a branching point, and a first wall section and a second wall section provided on at least one of the inner circumferential surface of the intake port, on the piston's top dead center side and on the piston's bottom dead center side, and extending in the axial direction of the intake port, wherein, viewed from the axial direction of the intake port, the first wall section is located on the first port section side of the branching point and the second wall section is located on the second port section side of the branching point, and the port injection injector is provided near the branching point.

[0008] In this invention, the first and second walls are provided on at least one of the first inner surface on the piston top dead center side and the second inner surface on the piston bottom dead center side of the inner circumferential surface of the intake port, extending in the axial direction of the intake port. Furthermore, viewed from the axial direction of the intake port, the first wall is located on the first port side of the branching point and the second wall is located on the second port side of the branching point. This allows for the formation of three flow paths, viewed from the axial direction of the intake port, between the outside of the first port and the first wall, between the first wall and the second wall, and between the outside of the second port and the second wall. This improves the flow velocity of fluids such as intake air passing through these flow paths and suppresses backflow of fluid into the intake port. Therefore, without requiring a valve or the like to switch flow paths, it is possible to suppress the residue of gaseous fuel injected from a port injection injector located near the branching point in the intake port, and even when gaseous fuel is injected into the intake port, backfire in the intake port can be suppressed.

[0009] Preferably, the first wall portion and the second wall portion are provided parallel to each other and connect the first inner surface and the second inner surface. In this case, preferably, the distance between the first wall portion and the second wall portion is 1 / 8 or more of the distance between the first inner surface and the second inner surface.

[0010] Preferably, the first wall and the second wall connect the first inner surface and the second inner surface and are arranged in a substantially inverted V shape when viewed from the axial direction of the intake port. In this case, preferably, the angle between the first wall and the second wall is 90 degrees or less.

[0011] Preferably, the first wall and the second wall connect the first inner surface and the second inner surface and are arranged in a substantially V-shape when viewed from the axial direction of the intake port. In this case, preferably, the angle between the first wall and the second wall is 100 degrees or less.

[0012] Preferably, the first wall portion and the second wall portion are arranged parallel to each other on the first inner surface.

[0013] Preferably, the first wall portion and the second wall portion are provided parallel to each other on the second inner surface.

[0014] Preferably, the first wall portion and the second wall portion extend from the second inner surface and are connected to each other to form a tunnel shape.

[0015] Preferably, the first and second wall portions are provided from the intake port inlet to at least the branching point.

[0016] Preferably, the first and second walls are provided beyond the branching point to the outlet side of the intake port. In this case, preferably, the first and second walls are formed from the middle of the axial direction on the inner circumferential surface of the intake port to the outlet of the intake port, without being formed at the inlet of the intake port. Also, in this case, preferably, the first and second walls are provided from the inlet side of the intake port to beyond the branching point to the outlet side of the intake port.

[0017] Preferably, the first wall portion and the second wall portion are each formed to a length greater than or equal to the axial distance from the downstream end to the outlet of the intake port, and are not formed all the way to the outlet of the intake port, but only from the inlet side of the intake port to a point in the axial direction on the inner circumferential surface of the intake port.

[0018] This invention can be suitably used in hydrogen engines that use hydrogen as a gaseous fuel. [Effects of the Invention]

[0019] According to this invention, an engine can be obtained that can reduce the number of parts and suppress backfire in the intake port even when using a port injection type injector. [Brief explanation of the drawing]

[0020] [Figure 1] This is a side view showing a hydrogen engine according to one embodiment of the present invention. [Figure 2] Figure 1 is a side view showing the main components of the hydrogen engine. [Figure 3] This is a cross-sectional view along line AA in Figure 2. [Figure 4]It is a perspective view showing a cylinder head. [Figure 5] It is a cross-sectional perspective view taken along line B-B of Figure 2. [Figure 6] It is a cross-sectional view taken along line C-C of Figure 2. [Figure 7] It is a diagram showing a comparative example. [Figure 8] (a) to (f) are diagrams showing modified examples in the case where the first wall portion and the second wall portion connect the first inner surface and the second inner surface and are provided parallel to each other. [Figure 9] (a) to (e) are diagrams showing modified examples in the case where the first wall portion and the second wall portion connect the first inner surface and the second inner surface and are provided in a substantially inverted V shape when viewed from the axial direction of the intake port, and (f) is a diagram showing a comparative example. [Figure 10] (a) to (f) are diagrams showing modified examples in the case where the first wall portion and the second wall portion connect the first inner surface and the second inner surface and are provided in a substantially V shape when viewed from the axial direction of the intake port. [Figure 11] (a) to (c) are diagrams showing modified examples of the first wall portion and the second wall portion. [Figure 12] (a) to (c) are diagrams showing modified examples in the case where the first wall portion and the second wall portion are not formed at the inlet of the intake port, but are formed from an axially intermediate position on the inner peripheral surface of the intake port to the outlet of the intake port. [Figure 13] (a) to (c) are diagrams showing modified examples in the case where the first wall portion and the second wall portion are formed from the inlet side of the intake port with a length equal to or greater than the axial distance from the downstream end to the outlet of the intake port, and (d) is a diagram showing a comparative example. [Figure 14] (a) to (c) are diagrams showing modified examples in the case where the first wall portion and the second wall portion are provided from the inlet side of the intake port to at least the branch point. [Mode for Carrying Out the Invention]

[0021] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0022] Referring to Figures 1 to 3, a hydrogen engine 10 according to one embodiment of the present invention is an engine that uses hydrogen as fuel and is mounted longitudinally. The hydrogen engine 10 includes a cylinder 12. A piston 14 is provided inside the cylinder 12 so as to be reciprocating. A cylinder head 16 is provided at one end of the cylinder 12 (the end on the piston's top dead center side), and a cylinder head cover 18 is provided on the upper part of the cylinder head 16. A crankcase 20 is provided at the other end of the cylinder 12 (the end on the piston's bottom dead center side). A crankshaft (not shown) is housed in the crankcase 20. The piston 14 and the crankshaft are connected by a connecting rod (not shown).

[0023] A bifurcated intake port 24 is provided in the cylinder head 16 to draw air into the combustion chamber 22 defined by the cylinder 12, piston 14, and cylinder head 16. A bifurcated exhaust port 26 is provided in the cylinder head 16 to exhaust air from the combustion chamber 22. Two intake valves 28 are provided in the cylinder head 16 to open and close the intake port 24, and two exhaust valves 30 are provided in the cylinder head 16 to open and close the exhaust port 26. Only one exhaust valve 30 is shown in Figure 3. A spark plug 32 is provided in the cylinder head 16 to ignite the combustion chamber 22. A port injection injector 34 is provided in the cylinder head 16 to inject hydrogen as gaseous fuel into the intake port 24.

[0024] Referring also to Figures 4 to 6, the intake port 24 includes an upstream common port section 36, a first port section 40 and a second port section 42 that branch downstream from the common port section 36 at a branching point 38, and a first wall section 44 and a second wall section 46 provided on the inner circumferential surface of the intake port 24. When the hydrogen engine 10 is mounted longitudinally, the first wall section 44 and the second wall section 46 become vertical walls extending in the vertical direction.

[0025] The first wall portion 44 and the second wall portion 46 extend in the axial direction of the intake port 24 (indicated by X in Figure 3) so as to connect the first inner surface 48 on the piston top dead center side and the second inner surface 50 on the piston bottom dead center side of the inner circumferential surface of the intake port 24 and to be parallel to each other. In this embodiment, the first wall portion 44 and the second wall portion 46 are provided from the inlet 52 of the intake port 24 to at least the branching point 38. Specifically, the first wall portion 44 is provided from the inlet 52 of the intake port 24 to the outlet 54 on the first port portion 40 side, and the second wall portion 46 is provided from the inlet 52 of the intake port 24 to the outlet 54 on the second port portion 42 side. The outlet 54 corresponds to the opening of the intake port 24 facing the combustion chamber 22, or in other words, to the valve seat. As shown in Figure 2, when viewed from the axial direction of the intake port 24, the first wall portion 44 is located on the first port portion 40 side of the branching point 38, and the second wall portion 46 is located on the second port portion 42 side of the branching point 38.

[0026] The two intake valves 28 are provided to open and close the outlets 54 on the first port section 40 side and the second port section 42 side, respectively. The port injection type injector 34 is provided near the branching point 38 and sprays hydrogen gas into the area S near the branching point 38 shown in Figure 6.

[0027] In this hydrogen engine 10, the first wall portion 44 and the second wall portion 46 are provided on at least one of the first inner surface 48 on the piston top dead center side and the second inner surface 50 on the piston bottom dead center side of the inner circumferential surface of the intake port 24, extending in the axial direction of the intake port 24. In this embodiment, the first wall portion 44 and the second wall portion 46 connect the first inner surface 48 and the second inner surface 50 and are provided parallel to each other. Furthermore, viewed from the axial direction of the intake port 24, the first wall portion 44 is located on the first port portion 40 side of the branching point 38 and the second wall portion 46 is located on the second port portion 42 side of the branching point 38. This allows for the formation of three flow paths between the outside of the first port portion 40 and the first wall portion 44, between the first wall portion 44 and the second wall portion 46, and between the outside of the second port portion 42 and the second wall portion 46, viewed from the axial direction of the intake port 24. In other words, an outer port can be formed between the outside of the first port portion 40 and the first wall portion 44, an inner port between the first wall portion 44 and the second wall portion 46, and an outer port can be formed between the outside of the second port portion 42 and the second wall portion 46. Therefore, the flow velocity of fluids such as intake air passing through the three flow paths can be improved, and backflow of fluid into the intake port 24 can be suppressed. Consequently, without requiring a valve or the like to switch the flow paths, it is possible to suppress the residue of hydrogen, which is a gaseous fuel injected from the port injection type injector 34 provided near the branching point 38, in the intake port 24, and backfire in the intake port 24 can be suppressed even when gaseous fuel is injected into the intake port 24. In other words, the number of parts can be reduced, and backfire in the intake port 24 can be suppressed even when a port injection type injector 34 is used.

[0028] This invention can be suitably used in hydrogen engines that use hydrogen as a gaseous fuel.

[0029] The following describes modified examples of the first and second wall sections.

[0030] Figure 7 shows a comparative example in which the intake port is divided into an upper first flow path and a lower second flow path in the direction of piston sliding by a partition plate 1 similar to that in Patent Document 1. In this comparative example, when air is drawn into the combustion chamber from the intake port under certain conditions, the flow velocity in the central area P near the outlet of the intake port is 8.6 m / s, and the flow velocity in the outer area Q is 7.4 m / s. The intake port of this comparative example includes a common port section and two branch port sections that branch downstream from the common port section, similar to the modified example described below.

[0031] Figures 8(a) to 8(f) show modified examples in which the first wall portion 44 and the second wall portion 46 connect the first inner surface 48 and the second inner surface 50 and are provided parallel to each other. In these modified examples, as shown in Figure 6, the first wall portion 44 and the second wall portion 46 are provided from the inlet 52 to the outlet 54 of the intake port 24 so as to extend in the axial direction of the intake port 24. The same applies to the modified examples shown in Figures 9 to 11.

[0032] In the modified examples shown in Figures 8(a) to 8(f), the distance between the first wall portion 44 and the second wall portion 46 is D, and the distance between the first inner surface 48 and the second inner surface 50 is E. The distance E is kept constant (40 mm), and the distance D is varied in 5 mm increments from 5 mm to 30 mm. Figures 8(a) to 8(f) show the flow velocity in the central area P and the outer area Q when air is drawn into the combustion chamber 22 from the intake port 24 under the same conditions as the comparative example in Figure 7 (the same applies to the comparative examples and modified examples in Figures 9 to 14). In the modified example in Figure 8(a), the flow velocity in the central area P near the outlet 54 of the intake port 24 is the same as in the comparative example in Figure 7, but the flow velocity in the outer area Q is higher, which suppresses backfire within the intake port 24. In each of the modified examples shown in Figures 8(b) to 8(f), the flow velocity in the central area P and the outer area Q near the outlet 54 of the intake port 24 is greater than in the comparative example shown in Figure 7, thereby suppressing backfire within the intake port 24. Therefore, it is preferable that the distance D between the first wall portion 44 and the second wall portion 46 is 1 / 8 or more of the distance E between the first inner surface 48 and the second inner surface 50.

[0033] Figures 9(a) to 9(e) show modified examples where the first wall portion 44a and the second wall portion 46a connect the first inner surface 48 and the second inner surface 50 and are arranged in a substantially inverted V shape when viewed from the axial direction of the intake port 24. Figure 9(f) shows a comparative example where the first wall portion 44a' and the second wall portion 46a' connect the first inner surface 48 and the second inner surface 50 and are arranged in a substantially inverted V shape when viewed from the axial direction of the intake port 24. In this case, the first wall portions 44a, 44a' and the second wall portions 46a, 46a' become slanted walls. In these modified and comparative examples, F is the distance between the first wall portions 44a, 44a' and the second wall portions 46a, 46a' on the first inner surface 48, and G is the angle between the first wall portions 44a, 44a' and the second wall portions 46a, 46a'. Then, the spacing F is kept constant (5 mm), and the angle G is varied from 20 degrees to 100 degrees. In each of the modified examples in Figures 9(a) to (e), the flow velocity in the central area P and the outer area Q near the outlet 54 of the intake port 24 is greater than in the comparative example shown in Figure 7, and backfire in the intake port 24 can be suppressed. In the comparative example in Figure 9(f), the flow velocity in the outer area Q near the outlet 54 of the intake port 24 is greater than in the comparative example shown in Figure 7, but the flow velocity in the central area P is smaller. Therefore, it is preferable that the angle G between the first wall portion 44a and the second wall portion 46a is 90 degrees or less.

[0034] Figures 10(a) to (f) show modified examples where the first wall portion 44b and the second wall portion 46b connect the first inner surface 48 and the second inner surface 50 and are arranged in a substantially V-shape when viewed from the axial direction of the intake port 24. In this case, the first wall portion 44b and the second wall portion 46b become slanted walls. In these modified examples, the distance between the first wall portion 44b and the second wall portion 46b on the second inner surface 50 is H, and the angle between the first wall portion 44b and the second wall portion 46b is I. The distance H is varied from 10 mm to 3 mm, and the angle I is varied from 20 degrees to 100 degrees. In each of the modified examples in Figures 10(a) to (f), the flow velocity in the central area P and the outer area Q near the outlet 54 of the intake port 24 is greater than in the comparative example shown in Figure 7, and backfire in the intake port 24 can be suppressed. Therefore, it is preferable that the angle I formed by the first wall portion 44b and the second wall portion 46b is 100 degrees or less.

[0035] Figure 11(a) shows a modified example in which the first wall portion 44c and the second wall portion 46c are provided parallel to each other on the first inner surface 48 without reaching the second inner surface 50. Figure 11(b) shows a modified example in which the first wall portion 44d and the second wall portion 46d are provided parallel to each other on the second inner surface 50 without reaching the first inner surface 48. Figure 11(c) shows a modified example in which the first wall portion 44e and the second wall portion 46e extend from the second inner surface 50 and are connected to each other to form a tunnel shape. In the modified example shown in Figure 11(a), the height J of the first wall portion 44c and the second wall portion 46c is approximately half the distance E between the first inner surface 48 and the second inner surface 50. In the modified example shown in Figure 11(b), the height J of the first wall portion 44d and the second wall portion 46d is approximately half the distance E between the first inner surface 48 and the second inner surface 50. In each of the modified examples shown in Figures 11(a) to 11(c), the flow velocity in the central area P and the outer area Q near the outlet 54 of the intake port 24 is greater than in the comparative example shown in Figure 7, thereby suppressing backfire within the intake port 24.

[0036] The variations in the length (depth direction) of the first and second wall sections will be explained below with reference to Figures 12 to 14.

[0037] Figures 12(a) to 12(c) show modified examples in which the first wall portion 44f and the second wall portion 46f are not formed at the inlet 52 of the intake port 24, but are formed from the middle of the axial direction on the inner circumferential surface of the intake port 24 to the outlet 54 of the intake port 24. In all of these modified examples, the first wall portion 44f and the second wall portion 46f are provided beyond the branching point 38 to the outlet 54 side of the intake port 24. In the modified examples shown in Figures 12 to 14, similar to the modified example shown in Figure 8(d), the first wall portion and the second wall portion connect the first inner surface and the second inner surface and are provided parallel to each other. In the modified examples shown in Figures 12(a) to 12(c), the distance from the inlet 52 of the intake port 24 to the upstream ends of the first wall portion 44f and the second wall portion 46f is denoted as K. The distance K is then varied in 20 mm increments from 20 mm to 60 mm. In each of the modified examples shown in Figures 12(a) to (c), the flow velocity in the central area P and the outer area Q near the outlet 54 of the intake port 24 is greater than in the comparative example shown in Figure 7, thereby suppressing backfire within the intake port 24.

[0038] Figures 13(a) to (c) show modified examples where the first wall portion 44g and the second wall portion 46g are formed from the inlet 52 side of the intake port 24, with a length equal to or greater than the axial distance L from the downstream end to the outlet 54 of the intake port 24. Figure 13(d) shows a comparative example where the first wall portion 44g' and the second wall portion 46g' are formed from the inlet 52 side of the intake port 24, with a length equal to or less than the axial distance L from the downstream end to the outlet 54 of the intake port 24. In Figures 13(a) and (b), the first wall portion 44g and the second wall portion 46g are formed from the inlet 52 of the intake port 24 to a point in the axial direction on the inner circumferential surface of the intake port 24, without being formed all the way to the outlet 54 of the intake port 24. In Figure 13(c), the first wall portion 44g and the second wall portion 46g are formed from the inlet 52 of the intake port 24 to the vicinity of the outlet 54. In these modified examples, the lengths of the first wall portion 44g and the second wall portion 46g are denoted as M. The length M is varied from 40 mm to 70 mm. In each modified example shown in Figures 13(a) to (c), the flow velocity in the central area P and the outer area Q near the outlet 54 of the intake port 24 is greater than in the comparative example shown in Figure 7, and backfire within the intake port 24 can be suppressed. In the comparative example shown in Figure 13(d), the flow velocity in the outer area Q near the outlet 54 of the intake port 24 is greater than in the comparative example shown in Figure 7, but the flow velocity in the central area P is smaller. Therefore, it is preferable that the first wall portion 44g and the second wall portion 46g are formed from the inlet 52 side of the intake port 24 with a length of at least L, which is the axial distance from the downstream end to the outlet 54 of the intake port 24.

[0039] Figures 14(a) to (c) show modified examples where the first wall portion 44h and the second wall portion 46h are provided from the inlet 52 side of the intake port 24 to at least the branching point 38. In Figure 14(a), the first wall portion 44h and the second wall portion 46h are provided up to the branching point 38. In Figures 14(b) and (c), the first wall portion 44h and the second wall portion 46h are provided beyond the branching point 38 to the outlet 54 side of the intake port 24. Also, in Figures 14(a) to (c), the first wall portion 44h and the second wall portion 46h are formed from the inlet 52 of the intake port 24. In these modified examples as well, the length of the first wall portion 44h and the second wall portion 46h is denoted as M. In these modified versions, the intake port 24 has a partition wall 56 extending axially on the inner circumferential surface of the intake port 24 in order to bring the branching point 38 closer to the inlet 52 of the intake port 24, with the length of the partition wall 56 being N. The overlap between the first wall portion 44h (second wall portion 46h) and the partition wall 56 is defined as O. The length N of the partition wall 56 is kept constant (30 mm), the lengths M of the first wall portion 44h and the second wall portion 46h are varied from 40 mm to 70 mm, and the overlap O is varied from 0 mm to 30 mm. In each of the modified versions shown in Figures 14(a) to (c), the flow velocity in the central area P and the outer area Q near the outlet 54 of the intake port 24 is greater than in the comparative example shown in Figure 7. Therefore, in the modified example shown in Figure 14(a), by providing the first wall portion 44h and the second wall portion 46h from the inlet 52 of the intake port 24 to the branching point 38, the flow velocity can be improved and backfire in the intake port 24 can be suppressed. In the modified examples shown in Figures 14(b) and (c), by providing the first wall portion 44h (second wall portion 46h) from the branching point 38 to the outlet 54 side of the intake port 24, and overlapping the first wall portion 44h (second wall portion 46h) with the partition wall 56, the flow velocity can be improved and backfire in the intake port 24 can be suppressed. In other words, in the modified examples shown in Figures 14(b) and (c), by providing the first wall portion 44h and the second wall portion 46h from the inlet 52 side of the intake port 24 to the outlet 54 side of the intake port 24 beyond the branching point 38, the flow velocity can be improved and backfire in the intake port 24 can be suppressed.

[0040] The modified examples shown in Figures 12 to 14 describe a case where the first wall portion and the second wall portion connect the first inner surface and the second inner surface and are provided parallel to each other, similar to the modified example shown in Figure 8(d), but the explanation is not limited to this. The modified examples shown in Figures 12 to 14 may also be modified according to the examples shown in Figures 8(a), (b), (c), (e), (f) and Figures 9 to 11.

[0041] In the embodiments described above, the case in which the hydrogen engine 10 is mounted vertically has been explained, but the invention is not limited to this. The hydrogen engine according to this invention may also be mounted horizontally. In this case, the first wall and the second wall become walls that extend in the horizontal direction.

[0042] The above-described embodiment illustrates the application of this invention to a hydrogen engine using hydrogen as a gaseous fuel, but it is not limited to this. This invention can also be applied to engines using natural gas as a gaseous fuel. [Explanation of Symbols]

[0043] 10 Hydrogen engine 12 cylinders 14 pistons 16 Cylinder head 22 Combustion chamber 24 intake ports 26 exhaust ports 34-port injection injector 36 Common Port Section 38 Branching Point 40 Port 1 Section 42 Second Port Section 44, 44a~44h, 44a', 44g' First wall 46, 46a~46h, 46a', 46g' Second wall 48 First Inner Surface 50 Second Inner Self 52 Intake port inlet 54 Intake port outlet D. Distance between the first wall and the second wall E Distance between the first inner surface and the second inner surface F Distance between the first wall and the second wall on the first inner surface G,I Angle between the first wall and the second wall H Distance between the first wall and the second wall on the second inner surface J Height of the first and second walls K Distance from the intake port inlet to the upstream end of the first wall (second wall) L: The axial distance from the downstream end of the first wall (second wall) to the outlet of the intake port. M Length of the first wall (second wall) N Length of partition O Overlap between the first wall (second wall) and the partition wall P: Central area near the outlet of the intake port Q: The outer area near the outlet of the intake port

Claims

1. Cylinder and A piston is provided within the cylinder so as to be reciprocable, A cylinder head provided on the cylinder, An intake port provided in the cylinder head for drawing air into the combustion chamber defined by the cylinder, the piston, and the cylinder head, The cylinder head is equipped with a port injection type injector for injecting gaseous fuel into the intake port, The intake port includes an upstream common port section, a first port section and a second port section branching downstream from the common port section at a branching point, and a first wall section and a second wall section provided on at least one of the first inner surface on the piston top dead center side and the second inner surface on the piston bottom dead center side of the inner circumferential surface of the intake port, and extending in the axial direction of the intake port. Viewed from the axial direction of the intake port, the first wall portion is located on the first port portion side of the branching point, and the second wall portion is located on the second port portion side of the branching point. The port injection type injector is provided near the branching point in the engine.

2. The engine according to claim 1, wherein the first wall portion and the second wall portion are provided parallel to each other and connect the first inner surface and the second inner surface.

3. The engine according to claim 2, wherein the distance between the first wall portion and the second wall portion is 1 / 8 or more of the distance between the first inner surface and the second inner surface.

4. The engine according to claim 1, wherein the first wall portion and the second wall portion connect the first inner surface and the second inner surface and are arranged in a substantially inverted V shape when viewed from the axial direction of the intake port.

5. The engine according to claim 4, wherein the angle between the first wall and the second wall is 90 degrees or less.

6. The engine according to claim 1, wherein the first wall portion and the second wall portion connect the first inner surface and the second inner surface and are arranged in a substantially V-shape when viewed from the axial direction of the intake port.

7. The engine according to claim 6, wherein the angle between the first wall and the second wall is 100 degrees or less.

8. The engine according to claim 1, wherein the first wall portion and the second wall portion are provided parallel to each other on the first inner surface.

9. The engine according to claim 1, wherein the first wall portion and the second wall portion are provided parallel to each other on the second inner surface.

10. The engine according to claim 1, wherein the first wall portion and the second wall portion extend from the second inner surface and are interconnected to form a tunnel shape.

11. The engine according to any one of claims 1 to 10, wherein the first wall portion and the second wall portion are provided from the inlet of the intake port to at least the branching point.

12. The engine according to any one of claims 1 to 10, wherein the first wall portion and the second wall portion are provided beyond the branching point to the outlet side of the intake port.

13. The engine according to claim 12, wherein the first wall portion and the second wall portion are not formed at the inlet of the intake port, but are formed from the middle of the axial direction on the inner circumferential surface of the intake port to the outlet of the intake port.

14. The engine according to claim 12, wherein the first wall portion and the second wall portion are provided from the inlet side of the intake port to the outlet side of the intake port beyond the branching point.

15. The engine according to any one of claims 1 to 10, wherein the first wall portion and the second wall portion each have a length greater than or equal to the axial distance from the downstream end to the outlet of the intake port, and are formed from the inlet side of the intake port to a point in the axial direction on the inner circumferential surface of the intake port without being formed all the way to the outlet of the intake port.

16. The engine according to claim 1, which is a hydrogen engine that uses hydrogen as the gaseous fuel.

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