Internal combustion engine and controller of internal combustion engine

Abstract

To provide an internal combustion engine and a controller of an internal combustion engine, capable of reducing hydrogen remaining in an intake port in a four-cycle port injection type internal combustion engine using hydrogen as fuel.SOLUTION: An internal combustion engine 1 is a port injection type internal combustion engine that injects hydrogen, which serves as fuel, toward an intake port 3c, and comprises a communication passage 30 that communicates a first space 31 inside the intake port 3c and a second space 32 outside the intake port 3c, and a communication switching unit 50 that switches a communication state of the communication passage 30. The communication switching unit 50 switches the communication state so that the communication passage 30 communicates them during a period where the intake valve 3a is closed.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an internal combustion engine and a control device for the internal combustion engine. [Background technology]

[0002] 2. Description of the Related Art Conventionally, in a gas engine for a vehicle using gas fuel such as natural gas, a configuration is known in which a surge tank is positioned below an intake valve head portion to suppress accumulation of gas fuel (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2000-064908 A Summary of the Invention [Problem to be solved by the invention]

[0004] In four-stroke port injection internal combustion engines, where hydrogen fuel is injected toward the intake port, hydrogen can remain in the intake port. In this case, for example, under high speed and high load conditions, when the intake valve opens, high temperature gas blows back from inside the cylinder, which can cause the hydrogen remaining in the intake port to ignite abnormally (backfire).

[0005] An object of the present invention is to provide an internal combustion engine and a control device for the internal combustion engine that are capable of reducing hydrogen remaining in an intake port in a four-stroke port injection type internal combustion engine that uses hydrogen as fuel. [Means for solving the problem]

[0006] One aspect of the present invention is a port injection type internal combustion engine that injects hydrogen as a fuel toward an intake port, and is equipped with a communication passage that connects a first space inside the intake port to a second space outside the intake port, and a communication switching unit that switches the communication state of the communication passage, where the communication switching unit switches the communication state so that the communication passage is connected while the intake valve is closed.

[0007] An internal combustion engine according to one aspect of the present invention is provided with a communication passage that communicates a first space in the intake port with a second space outside the intake port. The communication passage is switched between communication states by a communication switching unit, and is communicated while the intake valve is closed. As a result, while the intake valve is closed, the first space in the intake port communicates with the second space outside the intake port, making it possible to scavenge hydrogen in the intake port from the first space to the second space. Therefore, according to the internal combustion engine according to one aspect of the present invention, it is possible to reduce hydrogen remaining in the intake port in a four-stroke port injection type internal combustion engine that uses hydrogen as fuel.

[0008] In one embodiment, the communication switching unit may have a cylindrical member fixed to the intake valve and linked to the operation of the intake valve, and a housing portion including an inner wall surface that slides against an outer circumferential surface of the cylindrical member, the communication passage opening into the inner wall surface, and the outer circumferential surface of the cylindrical member may be configured not to block the opening of the communication passage while the intake valve is closed. In this case, the communication state of the communication passage can be switched by a mechanical configuration so as to be linked to the operation of the intake valve.

[0009] In one embodiment, the communication passage may be provided with a check valve that opens when the pressure in the first space is higher than the pressure in the second space. In this case, hydrogen in the intake port can be scavenged from the first space to the second space when the pressure in the first space is higher than the pressure in the second space, for example, in a high rotation speed and high load state.

[0010] Another aspect of the present invention is a control device for a port injection type internal combustion engine that injects hydrogen as a fuel toward an intake port, the internal combustion engine comprising a communication passage that connects a first space inside the intake port to a second space outside the intake port, and a communication switching unit that switches the communication state of the communication passage, the control device for the internal combustion engine comprising a control unit that controls the communication switching unit to switch the communication state based on the operating state of the internal combustion engine, and the control unit controls the communication switching unit so that the communication switching unit connects the communication passage during the period when the intake valve is closed.

[0011] In another aspect of the present invention, the internal combustion engine is provided with a communication passage that communicates a first space in the intake port with a second space outside the intake port. The communication switching unit is controlled by a control unit based on the operating state of the internal combustion engine. The communication passage has its communication state switched by the communication switching unit, and is communicated during a period when the intake valve is closed. As a result, during a period when the intake valve is closed, the first space in the intake port communicates with the second space outside the intake port, making it possible to scavenge hydrogen in the intake port from the first space to the second space. Therefore, according to the control device for an internal combustion engine according to another aspect of the present invention, it is possible to reduce hydrogen remaining in the intake port in a four-stroke port injection type internal combustion engine that uses hydrogen as fuel. Effect of the Invention

[0012] According to the present invention, it is possible to reduce hydrogen remaining in the intake port of a four-stroke port injection type internal combustion engine that uses hydrogen as fuel. [Brief description of the drawings]

[0013] [Figure 1] 1 is a schematic configuration diagram of an internal combustion engine according to an embodiment; [Diagram 2] FIG. 2 is a schematic cross-sectional view taken along line XX in FIG. [Diagram 3] 3 is an enlarged view of a main portion within the dashed frame in FIG. 2 when the communication passages are made to communicate with each other. [Figure 4] 3 is an enlarged view of a main portion within the dashed frame in FIG. 2 when the communication passages are not connected. [Diagram 5] 1 is a schematic configuration diagram of an internal combustion engine including an internal combustion engine control device according to an embodiment; [Figure 6] FIG. 6 is a schematic cross-sectional view taken along line XX in FIG. 5. [Figure 7] 6 is a flowchart showing an example of processing by the ECU in FIG. 5; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the drawings, the same or equivalent elements are designated by the same reference numerals, and duplicated explanations will be omitted.

[0015] [First embodiment] Fig. 1 is a schematic diagram of an internal combustion engine according to one embodiment. As shown in Fig. 1, the internal combustion engine 1 is configured as a port injection type hydrogen engine that injects hydrogen gas (hereinafter simply referred to as "hydrogen"), which is a fuel, toward an intake port. The internal combustion engine 1 is configured as a four-stroke reciprocating engine. The internal combustion engine 1 has a plurality of (for example, four) cylinders 2.

[0016] Fig. 2 is a schematic cross-sectional view taken along line XX in Fig. 1. As shown in Fig. 1 and Fig. 2, the internal combustion engine 1 has a cylinder head 3 including an intake valve 3a and an exhaust valve 3b, and a piston 5 provided in a cylinder 4.

[0017] An intake port 3c and an exhaust port (not shown) are formed in the cylinder head 3 so as to communicate with the combustion chamber 6. An intake valve 3a is provided at the downstream end of the intake port 3c. An exhaust valve 3b is provided at the upstream end of the exhaust port. A pipe 8 branched from the intake manifold is connected to the upstream side of the intake port 3c. The pipe 8 branched from the intake manifold forms part of an intake passage 7 of the internal combustion engine 1.

[0018] In the intake passage 7, for example, an air cleaner 16, a compressor 41 of a turbocharger 40, an intercooler 17, and a throttle valve 18 are arranged from upstream to downstream. In the exhaust passage 9, for example, a turbine 42 of the turbocharger 40 is arranged.

[0019] The internal combustion engine 1 may include an EGR unit 24 that recirculates a portion of the burnt gas generated in the combustion chamber 6 to the intake passage 7 as EGR (exhaust gas recirculation) gas. The EGR unit 24 may include an EGR passage 25, an EGR valve 26, an EGR cooler 27, a bypass passage 28, and a switching valve 29.

[0020] The internal combustion engine 1 includes an injector 11 that injects fuel toward the intake port 3c. For example, each of the injectors 11 is disposed for each intake port 3c. The injectors 11 are attached to a rail (not shown), and hydrogen is supplied to the injectors 11 from a fuel tank (not shown) via the rail.

[0021] In each cylinder 2, a combustion chamber 6 is defined by a cylinder head 3, a cylinder 4, and a piston 5. An ignition plug (not shown) is attached to the top of the combustion chamber 6. The internal combustion engine 1 takes in air and hydrogen via an intake valve 3a, burns the hydrogen in the combustion chamber 6 by ignition of the spark plug (not shown), and exhausts the exhaust gas produced by the combustion via an exhaust valve 3b.

[0022] The internal combustion engine 1 includes an ECU [Electronic Control Unit] 10. The ECU 10 is an electronic control unit that controls the internal combustion engine 1. The ECU 10 includes a CPU [Central Processing Unit], a ROM [Read Only Memory], a RAM [Random Access Memory], a communication circuit, and the like. For example, the ECU 10 loads a program stored in the ROM into the RAM and executes the program loaded into the RAM by the CPU, thereby achieving various functions. The ECU 10 may be composed of multiple electronic units.

[0023] An engine speed sensor 21 and an intake air amount sensor 22 are connected to the ECU 10 as sensors for acquiring the operating state of the internal combustion engine 1. The engine speed sensor 21 is a known detector that detects the engine speed of the internal combustion engine 1. The engine speed sensor 21 outputs a detection signal of the detected engine speed to the ECU 10. The intake air amount sensor 22 is a known detector that is provided in the intake passage 7 of the internal combustion engine 1 and detects a detection value related to the intake air amount of the internal combustion engine 1. The intake air amount sensor 22 outputs a detection signal of the intake air amount of the internal combustion engine 1 to the ECU 10.

[0024] The ECU 10 recognizes the operating state of the internal combustion engine 1 based on detection values ​​from various sensors. The ECU 10 calculates various control variables and the like based on the operating state of the internal combustion engine 1, and controls the internal combustion engine 1. For example, the ECU 10 controls the injector 11 so as to inject hydrogen supplied from the rail during the intake stroke when the intake valve 3a is open.

[0025] In the internal combustion engine 1, the intake valve 3a is installed in the cylinder head 3. The opening and closing of the intake valve 3a is controlled by an intake camshaft (not shown). For example, the intake camshaft rotates by utilizing the rotational motion transmitted from the crankshaft of the internal combustion engine 1 via a timing chain or the like. The intake valve 3a is pushed by the cam of the rotating intake camshaft via a valve lifter (not shown) or the like, and a valve spring (not shown) is compressed, causing the intake valve 3a to open. When the intake valve 3a is no longer pushed by the cam of the intake camshaft, the elastic force of the valve spring causes the intake valve 3a to close.

[0026] The intake valve 3a has a long, thin, rod-like valve stem 3d and a disk-shaped umbrella portion 3e formed at the tip of the valve stem 3d. The valve stem 3d is inserted into a cylindrical valve guide 3f embedded in the cylinder head 3. The valve stem 3d is guided by the valve guide 3f so that it reciprocates while inserted in the valve guide 3f when the intake valve 3a opens and closes.

[0027] FIG. 3 is an enlarged view of the main part within the broken line frame in FIG. 2 when the communication passage is connected. FIG. 4 is an enlarged view of the main part within the broken line frame in FIG. 2 when the communication passage is not connected. As shown in FIG. 3 and FIG. 4, the cylinder head 3 of the internal combustion engine 1 is provided with a communication passage 30 that communicates a first space 31 in the intake port 3c with a second space 32 outside the intake port 3c. The first space 31 is a space inside the intake port 3c, and is a space where hydrogen injected from the injector 11 may remain. The second space 32 is a space outside the intake port 3c, and is a space to which hydrogen remaining in the intake port 3c will go. In the example of FIG. 3, the second space 32 is an upper space 33 of the cylinder head 3. The upper space 33 of the cylinder head 3 is a space covered by a head cover (not shown). The second space 32 is, for example, a space that houses an intake camshaft.

[0028] The communication passage 30 is, for example, a through hole that connects the intake port 3c and the upper space 33. The through hole of the communication passage 30 may extend in a straight line, or may be curved so as to avoid the passage of the cooling water. The communication passage 30 is not limited to being tubular, and may, for example, connect the spaces of one or more chambers formed in the cylinder head 3 to communicate with the intake port 3c and the upper space 33.

[0029] A tubular member 51 is fixed to the valve stem 3d of the intake valve 3a. The tubular member 51 is, for example, a cylindrical member coaxial with the valve stem 3d. The tubular member 51 has an outer diameter larger than that of the valve guide 3f, for example. A chamfered portion 51b may be formed around the entire circumference of the tubular member 51 on the tip side (umbrella portion 3e side) of the valve stem 3d on the outer circumferential surface 51a of the tubular member 51. The outer circumferential surface 51a of the tubular member 51 may have a uniform outer diameter except for the chamfered portion 51b.

[0030] The bottom surface of the cylindrical member 51 on the opposite side to the umbrella portion 3e faces the bottom surface of the valve guide 3f on the umbrella portion 3e side. The cylindrical member 51 is fixed to the valve stem 3d so that, for example, when the intake port 3c is closed, the bottom surface of the cylindrical member 51 on the opposite side to the umbrella portion 3e abuts against the bottom surface of the valve guide 3f on the umbrella portion 3e side. The cylindrical member 51 can be fixed integrally to the valve stem 3d by, for example, shrink fitting. Such a cylindrical member 51 is fixed to the intake valve 3a and is linked to the operation of the intake valve 3a. The cylindrical member 51 reciprocates integrally with the valve stem 3d by the same amount of movement as the opening and closing operation of the intake valve 3a in conjunction with the opening and closing operation of the intake valve 3a.

[0031] The cylindrical member 51 is accommodated in the accommodation portion 52 so as to be capable of reciprocating motion in conjunction with the opening and closing motion of the intake valve 3a. The accommodation portion 52 is a recess provided in the cylinder head 3 of the internal combustion engine 1 so as to accommodate the cylindrical member 51. The accommodation portion 52 is a recess that defines, for example, a cylindrical space so as to define a space having a cross section corresponding to the outer circumferential shape of the cylindrical member 51.

[0032] A tapered surface 52b is formed on the umbrella portion 3e side of the accommodation portion 52 so as to correspond to the chamfered portion 51b of the cylindrical member 51. The tapered surface 52b is a step formed over approximately half the circumference of the inner wall surface 52a of the accommodation portion 52 in the circumferential direction with respect to the cylinder head 3 in a portion of the accommodation portion 52 where the intake port 3c does not pass. Even if the cylindrical member 51 should come off the valve stem 3d, the chamfered portion 51b of the cylindrical member 51 is caught on the tapered surface 52b, thereby preventing the cylindrical member 51 from falling off.

[0033] When assembling the intake valve 3a, the chamfered portion 51b and the tapered surface 52b can have an inclination angle and a width of the flat portion such that the valve stem 3d with the cylindrical member 51 fixed integrally therewith can be inserted into the accommodation portion 52 while being inclined with respect to the valve guide 3f. It is sufficient that the valve stem 3d is coaxial with the valve guide 3f when the cylindrical member 51 is inserted into the accommodation portion 52 so that the chamfered portion 51b passes through the tapered surface 52b.

[0034] The inner wall surface 52a of the accommodating portion 52 slides against the outer circumferential surface 51a of the tubular member 51 when the tubular member 51 reciprocates. Since the tubular member 51 is cylindrical, the tubular member 51 can rotate relative to the inner wall surface 52a of the accommodating portion 52 in the circumferential direction even when the tubular member 51 rotates around the axis integrally with the valve stem 3d.

[0035] The communication passage 30 opens to the inner wall surface 52a of the accommodation portion 52. For example, the communication passage 30 opens to the inner wall surface 52a of the accommodation portion 52 on the side opposite to the intake port 3c. When the intake valve 3a is closed, the communication passage 30 opens to a position on the inner wall surface 52a of the accommodation portion 52 that is not blocked by the cylindrical member 51. The communication passage 30 opens to a position on the inner wall surface 52a of the accommodation portion 52 that is blocked by the cylindrical member 51 that has moved by a predetermined valve opening amount when the intake valve 3a opens by a predetermined valve opening amount.

[0036] The predetermined valve opening amount means the valve opening amount of the intake valve 3a at which the communication state of the communication passage 30 is switched. The communication state of the communication passage 30 includes a state in which the communication passage 30 is not blocked and communicates the first space 31 and the second space 32, and a state in which the communication passage 30 is blocked and does not communicate the first space 31 and the second space 32. As an example, the predetermined valve opening amount can be about 1 mm to 2 mm when the valve lift of the intake valve 3a is 10 mm.

[0037] In the internal combustion engine 1 having such a configuration, hydrogen injected by the injector 11 during the period when the intake valve 3a is open may remain after the intake valve 3a is closed. As shown in FIG. 3, during the period when the intake valve 3a is closed and during the period when the intake valve 3a is open less than a predetermined valve opening amount, the opening of the communication passage 30 is not blocked by the outer peripheral surface 51a of the cylindrical member 51, and the first space 31 and the second space 32 are in communication with each other. This allows the remaining hydrogen to be scavenged from the first space 31 to the second space 32. On the other hand, as shown in FIG. 4, during the period when the intake valve 3a is open more than the predetermined valve opening amount, the opening of the communication passage 30 is blocked by the outer peripheral surface 51a of the cylindrical member 51, and the first space 31 and the second space 32 are not in communication with each other.

[0038] In other words, the cylindrical member 51 and the accommodating portion 52 cooperate to switch the communication state so that the communication passage 30 is communicated during the period when the intake valve 3a is closed and during the period when the intake valve 3a is open less than a predetermined valve opening amount. The cylindrical member 51 and the accommodating portion 52 cooperate to switch the communication state so that the communication passage 30 is not communicated during the period when the intake valve 3a is open to a predetermined valve opening amount or more (period when the intake valve 3a is not closed). That is, the cylindrical member 51 and the accommodating portion 52 constitute a communication switching portion 50 that switches the communication state of the communication passage 30.

[0039] Incidentally, the communication passage 30 may be provided with a check valve 34 that opens when the pressure in the first space 31 is higher than the pressure in the second space 32. The check valve 34 may be a known one-way valve or a PCV valve.

[0040] For example, in a situation where high-temperature gas is likely to blow back from inside the cylinder when the intake valve opens, such as under high-speed and high-load conditions, the pressure in the first space 31 is likely to be higher than the pressure in the second space 32. In such a situation, the check valve 34 opens to connect the communication passage 30, making it easier to scavenge residual hydrogen in the intake port 3c from the first space 31 to the second space 32. In addition, in a situation where there is little risk of high-temperature gas blowing back, such as under low-load conditions, the check valve 34 does not open to connect the communication passage 30, thereby preventing, for example, oil mist from flowing back into the intake port 3c and affecting the air-fuel ratio.

[0041] [Action and Effects] In the internal combustion engine 1 as described above, the communication passage 30 is provided to communicate the first space 31 in the intake port 3c with the second space 32 outside the intake port 3c. The communication state of the communication passage 30 is switched by the communication switching unit 50, and the communication passage 30 is made to communicate during the period when the intake valve 3a is closed. As a result, during the period when the intake valve 3a is closed, the first space 31 in the intake port 3c communicates with the second space 32 outside the intake port 3c, and it becomes possible to scavenge hydrogen in the intake port 3c from the first space 31 to the second space 32. Therefore, according to the internal combustion engine 1, it is possible to reduce hydrogen remaining in the intake port 3c in the four-stroke port injection type internal combustion engine 1 that uses hydrogen as fuel. Note that by mechanically realizing the switching of the communication state, it is possible to omit the addition of an actuator or the like that would be required when electronically realizing it.

[0042] The communication switching unit 50 has a cylindrical member 51 fixed to the intake valve 3a and linked to the operation of the intake valve 3a, and a housing portion 52 including an inner wall surface 52a that slides against an outer circumferential surface 51a of the cylindrical member 51. The communication passage 30 opens into the inner wall surface 52a, and the outer circumferential surface 51a of the cylindrical member 51 is configured not to block the opening of the communication passage 30 while the intake valve 3a is closed. This makes it possible to mechanically switch the communication state of the communication passage 30 in linkage with the operation of the intake valve 3a.

[0043] The communication passage 30 is provided with a check valve 34 that opens when the pressure in the first space 31 is higher than the pressure in the second space 32. This makes it possible to scavenge hydrogen in the intake port 3c from the first space 31 to the second space 32 when the pressure in the first space 31 is higher than the pressure in the second space 32, for example, in a high rotation speed and high load state.

[0044] [Second embodiment] Fig. 5 is a schematic diagram of an internal combustion engine equipped with an internal combustion engine control device according to one embodiment. Fig. 6 is a schematic cross-sectional view taken along line XX in Fig. 5. The second embodiment differs from the first embodiment in that the communication switching unit is controlled by the control unit.

[0045] 5 and 6, the control device 100 for an internal combustion engine according to one embodiment includes an ECU 10A (controller) that controls a solenoid valve 35 (communication switching unit) to switch the communication state based on the operating state of the internal combustion engine 1A. In the internal combustion engine 1A, for example, the cylindrical member 51 of the first embodiment may be omitted.

[0046] The ECU 10A controls the solenoid valve 35 so that the solenoid valve 35 opens the communication passage 30 while the intake valve 3a is closed. The ECU 10A controls the solenoid valve 35 so that the solenoid valve 35 does not open the communication passage 30 while the intake valve 3a is open. The solenoid valve 35 may be any valve that can switch the communication state of the communication passage 30, such as a known solenoid valve.

[0047] The ECU 10A recognizes whether the intake valve 3a is open or closed based on the operating state of the internal combustion engine 1A. In the ECU 10A, a cam position sensor for detecting the cam position of the intake camshaft may be used as a sensor for acquiring the operating state of the internal combustion engine 1A in addition to the engine rotation sensor 21 and the intake amount sensor 22.

[0048] Note that "the intake valve is closed" may mean a state in which the opening amount of the intake valve 3a is equal to or less than a predetermined intake valve closing judgment value. "The intake valve is closed" may mean a state in which the opening amount of the intake valve 3a is zero. The opening amount of the intake valve 3a may be the lift amount of the intake valve 3a from a state in which the intake valve 3a is seated on the valve seat.

[0049] An example of processing by the ECU 10A will be described with reference to Fig. 7. Fig. 7 is a flowchart showing an example of processing by the ECU in Fig. 5. The processing in Fig. 7 is executed, for example, while the internal combustion engine 1A is in operation.

[0050] 7, the ECU 10A acquires the operating state of the internal combustion engine 1A in S10. In S10, the ECU 10A recognizes whether the intake valve 3a is open or closed as the operating state of the internal combustion engine 1A.

[0051] In S11, the ECU 10A determines whether the intake valve 3a is closed. If it is determined that the intake valve 3a is closed (S11: YES), in S12, the ECU 10A controls the solenoid valve 35 so that the solenoid valve 35 opens the communication passage 30. On the other hand, if it is determined that the intake valve 3a is open (S11: NO), in S13, the ECU 10A controls the solenoid valve 35 so that the solenoid valve 35 does not open the communication passage 30. Thereafter, the ECU 10A ends the process of FIG. 7.

[0052] In the control device 100 for an internal combustion engine according to the second embodiment, the internal combustion engine 1A is provided with a communication passage 30 that communicates a first space 31 in the intake port 3c with a second space 32 outside the intake port 3c. The solenoid valve 35 is controlled by the ECU 10A based on the operating state of the internal combustion engine 1A. The communication passage 30 is switched by the solenoid valve 35 and is communicated during the period when the intake valve 3a is closed. As a result, during the period when the intake valve 3a is closed, the first space 31 in the intake port 3c communicates with the second space 32 outside the intake port 3c, making it possible to scavenge hydrogen in the intake port 3c from the first space 31 to the second space 32. Therefore, according to the control device 100 for an internal combustion engine, it is possible to reduce hydrogen remaining in the intake port 3c in the four-stroke port injection type internal combustion engine 1A that uses hydrogen as fuel.

[0053] [Variations] Although the embodiments according to the present invention have been described above, the present invention is not limited to the above-described embodiments.

[0054] In the above-described embodiments, the second space is exemplified as a space accommodating the intake camshaft, but is not limited thereto. For example, the second space may be a space inside the crankcase, or may be a space other than the intake port 3c, such as a separately installed collection tank.

[0055] In the first embodiment, the cylindrical member 51 fixed to the valve stem 3d and the accommodation portion 52 constitute the communication switching portion 50, but this is not intended to be limiting. Any configuration may be used as long as the communication state of the communication passage 30 is switched in conjunction with the operation of the intake valve by being fixed to the intake valve. For example, instead of a separate cylindrical member 51, an expanded diameter portion such as a cylindrical member may be formed on the valve stem itself.

[0056] In each of the above embodiments, the tapered surface 52b is a step formed in the circumferential direction of the inner wall surface 52a of the accommodation portion 52 with respect to the cylinder head 3 in the portion of the accommodation portion 52 where the intake port 3c does not pass, but is not limited thereto. For example, the tapered surface may be a step formed in the circumferential direction of the inner wall surface 52a of the accommodation portion 52 with respect to the cylinder head 3 in the portion of the accommodation portion 52 where the intake port 3c passes, on the opposite side to the tapered surface 52b. This configuration can be achieved by forming the accommodation portion deeper and moving the position of the communication passage 30 to a deeper position of the accommodation portion. In this case, since the tapered surface is located on the opposite side of the opening of the communication passage 30, when the chamfered portion 51b is guided by the tapered surface, the cylindrical member 51 is pressed in the direction of the opening of the communication passage 30. By utilizing this force, the sealing performance of the cylindrical member 51 in blocking the opening of the communication passage 30 can be improved.

[0057] In each of the above embodiments, the internal combustion engine 1, 1A is equipped with the turbocharger 40, but it may be equipped with another type of supercharger, or may not be equipped with a supercharger. The internal combustion engine may be provided with an electric blower or the like in the intake passage 7. What is important is that the pressure in the first space is higher than the pressure in the second space when the engine is in an operating state in which residual hydrogen is scavenged. [Explanation of symbols]

[0058] 1, 1A... internal combustion engine, 3a... intake valve, 3c... intake port, 10A... ECU (control unit), 30... communication passage, 31... first space, 32... second space, 34... check valve, 35... solenoid valve (communication switching unit), 50... communication switching unit, 51... cylindrical member, 51a... outer circumferential surface, 52... accommodation portion, 52a... inner wall surface, 100... control device for internal combustion engine.

Claims

1. A port injection type internal combustion engine in which hydrogen fuel is injected toward an intake port, a communication passage that communicates a first space in the intake port with a second space outside the intake port; A communication switching unit that switches the communication state of the communication passage, The communication switching unit switches the communication state so as to cause the communication passage to communicate while an intake valve is closed.

2. the communication switching portion includes a cylindrical member fixed to the intake valve and interlocked with the operation of the intake valve, and a housing portion including an inner wall surface that slides against an outer circumferential surface of the cylindrical member, The communication passage opens to the inner wall surface, 2. The internal combustion engine according to claim 1, wherein the outer peripheral surface of the tubular member does not block the opening of the communication passage while the intake valve is closed.

3. 3. The internal combustion engine according to claim 1, wherein the communication passage is provided with a check valve that opens when the pressure in the first space is higher than the pressure in the second space.

4. A control device for a port injection type internal combustion engine that injects hydrogen fuel toward an intake port, the internal combustion engine includes a communication passage that communicates a first space in the intake port with a second space outside the intake port, and a communication switching unit that switches a communication state of the communication passage, the control device for the internal combustion engine includes a control unit that controls the communication switching unit to switch the communication state based on an operating state of the internal combustion engine, The control unit controls the communication switching unit so that the communication switching unit opens the communication passage while an intake valve is closed.

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