Internal combustion engine

Abstract

The present invention provides an internal combustion engine that can suppress the increase in the force acting on the injector. [Solution] An internal combustion engine 10 using gaseous fuel comprises a delivery pipe 50, a cylinder head 30, an injector 60, and an elastic member 70. The cylinder head 30 has an insertion hole 31C that opens into the combustion chamber 13 of the internal combustion engine 10. The injector 60 has a body 61 connected to the delivery pipe 50 and a nozzle 62 extending from the body 61 and inserted into the insertion hole 31C, and injects the gaseous fuel in the delivery pipe 50 into the combustion chamber 13 from the nozzle 62. The elastic member 70 is positioned in a compressed state between the body 61 and the cylinder head 30 and applies a force to the body 61 that pushes it toward the delivery pipe 50.

Description

Technical Field

[0001] The present disclosure relates to an internal combustion engine.

Background Art

[0002] The internal combustion engine disclosed in Patent Document 1 includes a clamp member having two arm portions that support an injector and a bolt hole into which a fixing bolt is attached. The clamp member supports the injector with the two arm portions, and fixes the injector to the cylinder head by fixing the fixing bolt to the cylinder head.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of Invention

Problems to be Solved by the Invention

[0004] Incidentally, in order to position the injector, a method of pressing the injector toward the cylinder head by an elastic member such as a spring is conceivable. When the injector is pressed toward the cylinder head by the elastic member, the force pressing the injector toward the cylinder head needs to be larger than the combustion pressure of the internal combustion engine.

[0005] In particular, when using a fuel that tends to increase the combustion pressure of the internal combustion engine, such as gaseous fuel, the combustion pressure of the internal combustion engine tends to increase, so the force pressing the injector toward the cylinder head also increases. For this reason, a force exceeding the magnitude of the force required for positioning the injector acts on the injector.

Means for Solving the Problems

[0006] An internal combustion engine for solving the above problems is an internal combustion engine that uses a gaseous fuel, comprising: a delivery pipe for storing the gaseous fuel; a cylinder head having an insertion hole opening into the combustion chamber of the internal combustion engine; a main body connected to the delivery pipe; an injector having a nozzle extending from the main body and inserted into the insertion hole, which injects the gaseous fuel in the delivery pipe from the nozzle into the combustion chamber; and an elastic member disposed in a compressed state between the main body and the cylinder head, which applies a force to the main body that pushes it toward the delivery pipe.

[0007] With the above configuration, the injector is pushed toward the delivery pipe by the elastic member, so it is not necessary to make the elastic load greater than the combustion pressure load. Therefore, it is possible to suppress the increase in the force acting on the injector. [Effects of the Invention]

[0008] The internal combustion engine of this disclosure can suppress the increase in the force acting on the injector. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic diagram of an internal combustion engine. [Figure 2] Figure 2 is a perspective view of the injector. [Figure 3] Figure 3 is a perspective view of the connection point between the injector and the elastic member. [Modes for carrying out the invention]

[0010] (Embodiment) The internal combustion engine 10 of this disclosure will be described with reference to Figures 1 to 3. The internal combustion engine 10 shown in Figure 1 is a power source for a vehicle. The internal combustion engine 10 uses a gaseous fuel. The gaseous fuel is, for example, hydrogen fuel. The gaseous fuel may also be natural gas fuel.

[0011] <Overall Configuration of an Internal Combustion Engine> The internal combustion engine 10 comprises a cylinder block 20. The interior of the cylinder block 20 is divided, for example, by four cylinders 11.

[0012] Each cylinder 11 opens at the top surface of the cylinder block 20. A piston 12 is housed inside each cylinder 11. The piston 12 is capable of reciprocating within the cylinder 11. The piston 12 is connected to the crankshaft via a connecting rod. The connecting rod and crankshaft are not shown in the illustration.

[0013] The internal combustion engine 10 includes a cylinder head 30. The cylinder head 30 is positioned above the cylinder block 20. The cylinder head 30 is located above the combustion chamber 13. The cylinder head 30 includes a cylinder head body 31 and a cover 32. A valve train and the like are positioned on the upper surface of the cylinder head body 31. The cover 32 is fixed to the upper end of the cylinder head body 31 so as to cover the cylinder head body 31 and the valve train and the like.

[0014] The cylinder head body 31 is fixed to the upper end of the cylinder block 20. The cylinder head body 31 has a recess 31A. The recess 31A is located on the lower surface of the cylinder head body 31. The recess 31A is recessed upward in the axial direction of the cylinder 11. The combustion chamber 13 is partitioned by the inner wall of the recess 31A, the inner wall of the cylinder 11, and the top surface of the piston 12.

[0015] The cylinder head body 31 is provided with a first through-hole 31B that connects to the combustion chamber 13. The first through-hole 31B penetrates the cylinder head body 31 in the vertical direction. The cover 32 of the cylinder head 30 is provided with a second through-hole 32A. The second through-hole 32A is located in substantially the same position as each of the first through-holes 31B in the cylinder head body 31 within the cover 32. The axis of the second through-hole 32A is on the same straight line as the axis of the first through-hole 31B.

[0016] An injector 60 is inserted into the first through hole 31B and the second through hole 32A. The injector 60 is attached to the cylinder head 30 by being inserted into the first through hole 31B and the second through hole 32A.

[0017] The first through hole 31B includes an insertion hole 31C in which a nozzle 62 of the injector 60 described later is disposed. The insertion hole 31C opens to the combustion chamber 13 of the internal combustion engine 10. The insertion hole 31C is provided below the cylinder head main body 31.

[0018] <Fuel supply device> The internal combustion engine 10 includes a fuel supply device 40. The fuel supply device 40 includes a delivery pipe 50 that stores gaseous fuel, an injector 60, and an elastic member 70. In FIG. 1, the cylinder block 20 and the cylinder head 30 are shown in a cross-sectional view, and the fuel supply device 40 is shown in a side view.

[0019] <Delivery pipe> Gaseous fuel is supplied to the delivery pipe 50 by a fuel pump. The delivery pipe 50 has a substantially cylindrical shape. The delivery pipe 50 has a pipe main body 51 and branch portions 52. The pipe main body 51 extends above the cylinder head 30 in the direction in which the cylinders 11 are arranged.

[0020] The branch portion 52 has a substantially cylindrical shape. The branch portion 52 protrudes from the pipe main body 51 toward the first through hole 31B and the second through hole 32A of the cylinder head 30. An injector 60 that supplies fuel to the internal combustion engine 10 is connected to each branch portion 52.

[0021] <Injector> As shown in FIG. 2, the injector 60 has a main body 61 and a nozzle 62. The main body 61 has a substantially cylindrical shape. The main body 61 is connected to the delivery pipe 50. The nozzle 62 extends from the main body 61. The outer diameter of the nozzle 62 is smaller than the outer diameter of the main body 61.

[0022] As shown in Figure 1, with the injector 60 mounted on the cylinder head 30, at least a portion of the nozzle 62 positioned in the insertion hole 31C of the cylinder head 30 is located inside the combustion chamber 13. The injector 60 injects gaseous fuel from the nozzle 62 into the combustion chamber 13 of the internal combustion engine 10.

[0023] In the axial direction of the injector 60, the end of the nozzle 62 opposite to the main body 61 is called the tip 60B of the injector 60. In the axial direction of the injector 60, the end of the main body 61 opposite to the nozzle 62 is called the base end 60A of the injector 60.

[0024] As shown in Figure 2, an O-ring 63 is attached to the base end 60A of the injector 60. When the injector 60 is attached to the delivery pipe 50, the base end 60A of the injector 60 is inserted into the cylinder of the branch section 52. The gap between the outer surface of the main body 61 and the inner surface of the branch section 52 is sealed by the O-ring 63.

[0025] The gaseous fuel stored in the delivery pipe 50 flows from the base end 60A of the injector 60 toward the tip end 60B of the injector 60. In the following explanation, the base end 60A side of the injector 60 may be referred to as the upper side, and the tip end 60B side as the lower side.

[0026] As shown in Figure 2, the main body 61 includes a flange 61A. The flange 61A protrudes from the outer circumferential surface of the main body 61 over its entire circumference. When the injector 60 is viewed from the axial direction of the injector 60, the flange 61A is ring-shaped. As shown in Figure 1, the diameter of the flange 61A is larger than the diameter of the first through hole 31B.

[0027] As shown in Figure 2, the portion of the main body 61 closer to the base end 60A than the flange 61A includes a stepped portion 61B in which the shape of the outer circumference of the main body 61 changes in a stepped manner. In the stepped portion 61B, the outer diameter of the main body 61 becomes smaller towards the base end 60A of the injector 60.

[0028] The main body 61 includes a projection 61C. The projection 61C is a flat, rectangular tube. The projection 61C protrudes from the outer circumferential surface of the main body 61. The projection 61C is located on the base end 60A side of the main body 61, relative to the flange 61A. The projection 61C extends with an inclination such that its tip 60B is located upward.

[0029] A connector 61D for transmitting electrical signals is connected to the tip 60B of the protruding portion 61C. The connector 61D is a roughly rectangular box shape with an opening on the top. Multiple terminals located inside the connector 61D are connected to a solenoid valve or the like built into the injector 60.

[0030] <Elastic material> As shown in Figures 1 and 3, the elastic member 70 is positioned in a compressed state between the body 61 of the injector 60 and the cylinder head 30. The upper end of the elastic member 70 contacts the lower end of the branch 52 of the delivery pipe 50. The lower end of the elastic member 70 contacts the upper end of the cover 32 of the cylinder head 30. The elastic member 70 is mounted on the injector 60 at a position below the flange 61A of the injector 60.

[0031] An example of an elastic member 70 is a spring 71. In plan view, the spring 71 has a C-shape. The spring 71 has at least one slit 72 extending in the circumferential direction of the spring 71. The spring 71 is provided with a plurality of slits 72. Each slit 72 is provided in the spring 71 in a vertical direction. The spring 71 is able to stretch and contract in the vertical direction by elastic deformation of the spring 71 so that the groove width of each slit 72 decreases.

[0032] The spring 71 in this embodiment has a clamping structure for gripping the body 61 of the injector 60. The spring 71 is attached to the injector 60 by gripping the body 61 of the injector 60.

[0033] The elastic member 70 applies a force to the main body 61 that pushes it toward the delivery pipe 50. The force that pushes the main body 61 toward the cylinder head 30 is defined as the fuel pressure load F1. The force that the elastic member 70 applies to the main body 61 is defined as the elastic load F2. The force that pushes the injector 60 toward the delivery pipe 50 is defined as the combustion pressure load F3. In Figure 1, the directions of the fuel pressure load F1, the elastic load F2, and the combustion pressure load F3 are indicated by arrows.

[0034] The fuel pressure load F1 is generated by the pressure of the gaseous fuel supplied from the delivery pipe 50 to the injector 60. The combustion pressure load F3 is generated by the combustion pressure in the combustion chamber 13. The fuel pressure load F1 is less than the sum of the elastic load F2 and the combustion pressure load F3. Preferably, the elastic load F2 is greater than the fuel pressure load F1.

[0035] The effects of this embodiment will now be explained. (1) In this embodiment, the internal combustion engine 10 uses gaseous fuel. The internal combustion engine 10 comprises a delivery pipe 50, a cylinder head 30, an injector 60, and an elastic member 70. The delivery pipe 50 stores the gaseous fuel. The cylinder head 30 has an insertion hole 31C that opens into the combustion chamber 13 of the internal combustion engine 10. The injector 60 has a body 61 connected to the delivery pipe 50 and a nozzle 62 extending from the body 61 and inserted into the insertion hole 31C. The injector 60 injects the gaseous fuel in the delivery pipe 50 into the combustion chamber 13 from the nozzle 62. The elastic member 70 is positioned in a compressed state between the body 61 and the cylinder head 30. The elastic member 70 applies a force to the body 61 that pushes it toward the delivery pipe 50.

[0036] According to the above configuration, the elastic member 70 pushes the injector 60 toward the delivery pipe 50, so it is not necessary to make the elastic load F2 greater than the combustion pressure load F3. Therefore, it is possible to suppress the increase in the force acting on the injector 60.

[0037] (2) The fuel pressure load F1 is smaller than the sum of the elastic load F2 and the combustion pressure load F3. Therefore, the elastic member 70 always presses the injector 60 against the delivery pipe 50. Thus, the injector 60 can be positioned appropriately.

[0038] <Example of changes> This disclosure may be implemented with modifications as follows. This disclosure and the following examples of modifications may be combined with each other to the extent that they do not conflict with each other technically.

[0039] The location of the injector 60 is not limited to the first through-hole 31B and the second through-hole 32A of the cylinder head 30. For example, the injector 60 may be placed in a through-hole provided on the side of the cylinder block 20, and gaseous fuel may be injected by the injector 60 from the side of the cylinder 11.

[0040] The shape of the body 61 of the injector 60 is not limited to the examples of the embodiment. The portion of the body 61 closer to the base end 60A than the flange 61A may be, for example, rectangular. The injector 60 only needs to be able to inject fuel from at least the tip 60B.

[0041] The number of cylinders 11 is not limited to the examples of the embodiment. The number of cylinders 11 may be five or more, or three or fewer. The structure of spring 71 is not limited to the examples of embodiments. Spring 71 may have a structure such as a coil spring. [Explanation of Symbols]

[0042] 10...Internal combustion engine, 13...Combustion chamber, 30...Cylinder head, 31C...Insertion hole, 50...Delivery pipe, 60...Injector, 61...Main body, 62...Nozzle, 70...Elastic member.

Claims

1. An internal combustion engine that uses gaseous fuel, A delivery pipe for storing the aforementioned gaseous fuel, A cylinder head having an insertion hole that opens into the combustion chamber of the internal combustion engine, An injector having a main body connected to the delivery pipe and a nozzle extending from the main body and inserted into the insertion hole, which injects the gaseous fuel in the delivery pipe from the nozzle into the combustion chamber, The system includes an elastic member that is positioned in a compressed state between the main body and the cylinder head, and that applies a force to the main body that pushes the main body toward the delivery pipe. Internal combustion engine.

2. The force that pushes the main body toward the cylinder head, generated by the pressure of the gaseous fuel supplied from the delivery pipe to the injector, is defined as the fuel pressure load. The force that the elastic member applies to the main body is defined as the elastic load. When the force generated by the combustion pressure in the combustion chamber that pushes the injector toward the delivery pipe is defined as the combustion pressure load, The aforementioned fuel pressure load is less than the sum of the elastic load and the combustion pressure load. The internal combustion engine according to claim 1.

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