Control system for auxiliary chamber type internal combustion engine

Abstract

To provide a control system for an auxiliary chamber type internal combustion engine that can form a mixture with a thick fuel concentration around an auxiliary chamber in a main combustion chamber in which a vortex flow is formed.SOLUTION: A control system for an auxiliary chamber type internal combustion engine includes: a main combustion chamber in which a vortex flow is formed; an auxiliary combustion chamber disposed to the main combustion chamber via a partition wall; and a fuel injection valve for injecting a fuel into the main combustion chamber. The fuel injection valve has a first injection that is injected along the vortex flow and a second injection that is injected toward the auxiliary combustion chamber.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a control system for an internal combustion engine with a separate combustion chamber. [Background technology]

[0002] Conventionally, a pre-combustion chamber type internal combustion engine has been known (see, for example, Patent Document 1). The pre-combustion chamber type internal combustion engine of Patent Document 1 comprises a main combustion chamber and a pre-combustion chamber, an ignition device disposed in the pre-combustion chamber, and a fuel injection valve disposed in the main combustion chamber. The pre-combustion chamber type internal combustion engine of Patent Document 1 is a passive type pre-combustion chamber type internal combustion engine that forms an air-fuel mixture in the pre-combustion chamber by supplying fuel injected from the main combustion chamber to the pre-combustion chamber. The air-fuel mixture formed in the pre-combustion chamber is ignited by an ignition device to form a flame. The flame formed in the pre-combustion chamber is injected into the main combustion chamber via a communication passage. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 7255673 Summary of the Invention [Problem to be solved by the invention]

[0004] In such a passive type pre-combustion chamber internal combustion engine, it is preferable to form a fuel-rich mixture around the pre-combustion chamber and supply the mixture to the pre-combustion chamber. In the pre-combustion chamber internal combustion engine of Patent Document 1, fuel is sprayed from the fuel injection valve to the outside of the pre-combustion chamber, forming a fuel-rich mixture around the pre-combustion chamber. Patent Document 1 does not disclose how fuel injection should be performed when a vortex is formed in the main combustion chamber.

[0005] An object of the present disclosure is to provide a control system for a pre-combustion chamber type internal combustion engine that can form a fuel-rich mixture around the pre-combustion chamber in the main combustion chamber where a vortex is formed. [Means for solving the problem]

[0006] The control system for an auxiliary combustion chamber type internal combustion engine according to the present disclosure comprises a main combustion chamber in which a vortex is formed, an auxiliary combustion chamber arranged with a partition wall between it and the main combustion chamber, and a fuel injection valve that injects fuel into the main combustion chamber, the fuel injection valve having a first injection that is injected along the vortex and a second injection that is injected toward the auxiliary combustion chamber. [Effects of the Invention]

[0007] According to this control system for a pre-combustion chamber internal combustion engine, the first injection is carried by the vortex to form a mixture around the main combustion chamber and supply a fuel spray around the pre-combustion chamber. The second injection is injected toward the pre-combustion chamber and supply a fuel spray around the pre-combustion chamber. The control system for a pre-combustion chamber internal combustion engine forms a layer of mixture around the main combustion chamber and a layer of high fuel concentration around the pre-combustion chamber by the first injection and the second injection. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a system diagram of a control system for an internal combustion engine with a pre-combustion chamber according to an embodiment of the present disclosure, and a side cross-sectional view of the vicinity of a communication passage showing an injection pattern. [Figure 2] FIG. 2 is a bottom cross-sectional view of the vicinity of a communication passage, illustrating the injection pattern of the pre-chamber type internal combustion engine according to the embodiment of the present disclosure. [Figure 3] 4 is a flowchart illustrating a control procedure executed by a control device according to an embodiment of the present disclosure. [Figure 4] FIG. 10 is a bottom cross-sectional view of the vicinity of a communication passage, illustrating an injection pattern of an internal combustion engine with a pre-combustion chamber according to another embodiment. [Figure 5] FIG. 10 is a bottom cross-sectional view of the vicinity of a communication passage, illustrating an injection pattern of an internal combustion engine with a pre-combustion chamber according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the sliding direction of piston 8 is indicated as P, the side where intake valve 14 is located is indicated as intake side IN, the side where exhaust valve 16 is located is indicated as exhaust side EX, and the direction in which ridge line X1 extends is indicated as ridge line direction X.

[0010] As shown in FIG. 1, the control system 1 for the auxiliary combustion chamber type internal combustion engine E includes a main combustion chamber 2, an auxiliary combustion chamber 3, a communication passage 4, an ignition device 6, a piston 8, a fuel injection valve 9, and a control device 20.

[0011] The main combustion chamber 2 is a space surrounded by the cylinder 10a of the cylinder block 10, the cylinder head 12, and the piston 8. In this embodiment, the main combustion chamber 2 has a pent roof shape, with two slopes formed toward the intake port 12a side and the exhaust port 12b side of the cylinder head 12. The main combustion chamber 2 is connected to the intake port 12a via an intake valve 14. The intake port 12a is connected, for example, to an intake passage (not shown). The intake port 12a in this embodiment forms a tumble flow T in the main combustion chamber 2. The main combustion chamber 2 is connected to the exhaust port 12b via an exhaust valve 16. The exhaust port 12b is connected, for example, to an exhaust passage (not shown).

[0012] The auxiliary combustion chamber 3 protrudes from the cylinder head 12 toward the main combustion chamber 2 and is separated from the main combustion chamber 2 by an auxiliary combustion chamber wall (an example of a partition wall) 5. The auxiliary combustion chamber 3 of this embodiment is located adjacent to the main combustion chamber 2 at the top of the pent roof shape, and has a space surrounded by the auxiliary combustion chamber wall 5. The center line C2 of the auxiliary combustion chamber 3 of this embodiment coincides with the center line C1 of the main combustion chamber 2.

[0013] The auxiliary combustion chamber wall 5 has a side wall 51 and a bottom wall 52. In this embodiment, the side wall 51 is formed in a cylindrical shape, and the bottom wall 52 is formed in a hollow hemispherical shape.

[0014] The communication passages 4 are provided in the auxiliary combustion chamber wall 5. As shown in Fig. 2, the communication passages 4 communicate between the main combustion chamber 2 and the auxiliary combustion chamber 3. In this embodiment, a total of eight communication passages 4 are provided: two in the direction of the ridge line X1 of the pent roof, three toward the intake side, and three toward the exhaust side.

[0015] As shown in Fig. 1, the ignition device 6 is disposed in the auxiliary combustion chamber 3. The ignition device 6 ignites the air-fuel mixture in the auxiliary combustion chamber 3 by discharging the current flowing through the ignition coil using the central electrode and the side electrode.

[0016] The piston 8 is housed in the cylinder 10a and slides within the cylinder 10a. The piston 8 surrounds the main combustion chamber 2 from below.

[0017] The fuel injection valve 9 injects fuel toward the main combustion chamber 2 and the auxiliary combustion chamber 3, forming an air-fuel mixture in the main combustion chamber 2 and the auxiliary combustion chamber 3. In this embodiment, the fuel injection valve 9 has a first fuel injection valve 9a and a second fuel injection valve 9b. The first fuel injection valve 9a is arranged on the exhaust side EX. The first fuel injection valve 9a is a direct injection type that injects fuel directly into the main combustion chamber 2. The second fuel injection valve 9b is arranged on the intake side IN. The second fuel injection valve 9b is also a direct injection type that injects fuel directly into the main combustion chamber 2. The injection amount Q1 of the first injection F1 is greater than the injection amount Q2 of the second injection F2.

[0018] The first fuel injector 9a injects the first injection F1. The first injection F1 is injected along the tumble flow T. More specifically, the tumble flow T flows toward the piston 8 in the sliding direction P on the exhaust side EX. The first fuel injector 9a injects the first injection F1 toward the bottom dead center side of the sliding direction P of the piston 8. As a result, the first injection F1 rides on the tumble flow T flowing toward the piston 8. The first injection F1 riding on the tumble flow T flows toward the top dead center side (cylinder head 12 side) in the sliding direction P on the intake side IN and flows around the auxiliary combustion chamber wall 5. Here, the direction along the tumble flow T may be any direction in which the angle between the central axis of the spray of the first injection F1 and the tangent to the tumble flow T is less than 90 degrees. The same applies to the direction along the swirl flow S described below.

[0019] As shown in FIG. 2, the first fuel injection valve 9a has multiple nozzle holes and injects the first injection F1 in multiple directions. In this embodiment, the first fuel injection valve 9a has a central nozzle hole F1a that injects toward the center line C2 of the auxiliary combustion chamber 3, and two side nozzle holes F1b that are arranged on both sides of the central nozzle hole F1a and inject the first injection F1 toward the ridge line X1. In other words, the first fuel injection valve 9a forms the first injection F1 in three different directions. Of the multiple nozzle holes of the first fuel injection valve 9a, the injection amount Qm of the central nozzle hole is greater than the injection amount Qs of the other nozzle holes. In this embodiment, the injection amount Qm of the central nozzle hole F1a is greater than the injection amount Qs of the side nozzle holes F1b.

[0020] The second injection F2 injects fuel toward the auxiliary combustion chamber wall 5. The second injection F2 collides with the auxiliary combustion chamber wall 5 and the spray diffuses. The second fuel injection valve 9b injects the second injection F2 toward the center line C2 of the auxiliary combustion chamber 3.

[0021] The control device 20 controls the injection timing of the first injection F1 and the injection timing of the second injection F2. The control device 20 is actually an ECU (Electronic Control Unit) configured by a microcomputer including an arithmetic unit, a memory, an input / output buffer, etc. The control device 20 controls the fuel injection valves 9 based on maps and programs stored in the memory. In this embodiment, the control device 20 is electrically connected to the first fuel injection valve 9a and the second fuel injection valve 9b, and controls the injection timing of the first injection F1 by the first fuel injection valve 9a and the injection timing of the second injection F2 by the second fuel injection valve 9b.

[0022] Next, a control procedure executed by the control device 20 will be described with reference to the flowchart of Fig. 3. The control device 20 starts the control procedure when an ignition switch (not shown) is turned on.

[0023] In step S1, the control device 20 determines whether the first injection F1 has been completed. The control device 20 may determine the injection amount Q1 of the first injection F1 according to the rotation speed and load of the pre-chamber internal combustion engine E. If the control device 20 determines that the first injection F1 has been completed (YES in step S1), the control device 20 proceeds to step S2.

[0024] In step S2, the control device 20 determines whether the intake valve 14 (an example of an intake valve) is closed. The control device 20 may determine whether it is time to close the intake valve 14 from the rotational position of the crankshaft, and determine that the intake valve 14 is closed. If the control device 20 determines that the intake valve 14 is closed (YES in step S2), the process proceeds to step S3.

[0025] In step S3, the control device 20 executes the second injection F2. The control device 20 may determine the injection amount Q2 of the second injection F2 according to the rotation speed and load of the pre-combustion chamber internal combustion engine E. After executing the second injection F2, the control device 20 proceeds to step S1. If the control device 20 determines that the first injection F1 has not been completed (NO in step S1), it continues the processing of step S1 until the first injection F1 is completed. If the control device 20 determines that the intake valve 14 has not been closed (NO in step S2), it continues the processing of step S2 until the intake valve 14 is closed.

[0026] In the auxiliary combustion chamber type internal combustion engine E configured as above, the first fuel injection F1 injected from the central nozzle F1a of the first fuel injection valve 9a rides on the tumble flow and flows to the periphery of the auxiliary combustion chamber wall 5. After flowing to the periphery of the auxiliary combustion chamber wall 5, the first fuel injection F1 hits the auxiliary combustion chamber wall 5 and is dispersed.

[0027] The control device 20 injects the first injection F1 before the second injection F2. As a result, the first injection F1 injected from the side nozzle F1b of the first fuel injection valve 9a is carried by the tumble flow T and diffuses, forming a layer of a mixture with a homogeneous air-fuel ratio along the cylinder 10a of the main combustion chamber 2 and the top surface of the piston 8.

[0028] The second injection F2 injected from the second fuel injection valve 9b collides with the auxiliary combustion chamber wall 5 and diffuses. As a result, the second injection F2 forms a layer of a fuel-rich mixture around the auxiliary combustion chamber wall 5. In this embodiment, the second injection F2 is injected after the first injection F1 is completed. As a result, the fuel concentration of the mixture around the auxiliary combustion chamber wall 5 formed by the first injection F1 can be further enriched by the second injection F2.

[0029] The control device 20 ends the first injection F1 before the second injection F2 is started. This makes it easier for a layer of a stoichiometric air-fuel mixture or a layer of a lean mixture with a low fuel concentration (lean) to form along the cylinder 10a and the top surface of the piston 8. On the other hand, a layer of a rich mixture with a high fuel concentration (rich) to form around the auxiliary combustion chamber wall 5. This allows the control system 1 of the auxiliary combustion chamber internal combustion engine E to achieve stratified charge combustion.

[0030] Furthermore, the control device 20 injects the second injection F2 after the intake valve 14 is closed. This allows the control system 1 of the auxiliary combustion chamber internal combustion engine E to prevent the second injection F2 from being blown back into the intake port 12a. As a result, a layer of a mixture with a higher fuel concentration is likely to be formed around the auxiliary combustion chamber wall 5.

[0031] The air-fuel mixture formed around the auxiliary combustion chamber wall 5 flows into the auxiliary combustion chamber 3 through the communication passage 4. The air-fuel mixture that flows into the auxiliary combustion chamber 3 is ignited by the ignition device 6. The ignited air-fuel mixture becomes a flame. The flame passes through the communication passage 4 and is injected into the main combustion chamber 2 as a jet flame.

[0032] As described above, according to the present disclosure, it is possible to provide a control system 1 for an internal combustion engine E with a pre-combustion chamber that can form a fuel-rich mixture around the pre-combustion chamber 3 in the main combustion chamber 2 where a vortex is formed.

[0033] <Other embodiments> Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments, and various modifications are possible within the scope of the gist of the invention. In particular, the multiple modifications described in this specification can be arbitrarily combined as necessary.

[0034] (a) In the above embodiment, the vortex formed in the main combustion chamber 2 is a tumble flow T. However, the present disclosure is not limited to this. As shown in FIG. 4 , the vortex may be a swirl flow S. More specifically, the control system 1 of the pre-combustion chamber internal combustion engine E may form a swirl flow S that flows along the cylinder 10a in the main combustion chamber 2 of the pre-combustion chamber internal combustion engine E. The control device 20 may control the first fuel injector 9a to inject the first injection F1 along the swirl flow S. The control device 20 may control the second fuel injector 9b to inject the second injection F2 toward the pre-combustion chamber wall 5. This allows the control device 20 to form a layer of a stoichiometric or lean mixture near the cylinder 10a and a layer of a rich mixture around the pre-combustion chamber wall 5. As a result, the control system 1 of the pre-combustion chamber internal combustion engine E can achieve stratified charge combustion.

[0035] (b) In the above embodiment, an example has been described in which the first injection F1 and the second injection F2 are performed using the first fuel injection valve 9a and the second fuel injection valve 9b, but the present disclosure is not limited to this. As shown in FIG. 5, the control system 1 for the pre-combustion chamber type internal combustion engine E may perform the first injection F1 and the second injection F2 using a single fuel injection valve 9. The control device 20 may control a single fuel injection valve 9. In this case, the fuel injection valve 9 may inject the first injection F1 along the tumble flow T (see FIG. 1) or along the swirl flow S (see FIG. 4). [Explanation of symbols]

[0036] 1: Control system for pre-chamber internal combustion engines E: Pre-chamber internal combustion engine 2: Main combustion chamber, 3: Auxiliary combustion chamber, 4: Connecting passage, 5: Auxiliary combustion chamber wall 6: Ignition device, 8: Piston 9: fuel injection valve, 9a: first fuel injection valve, 9b: second fuel injection valve 20: Control device F1: 1st injection, F2: 2nd injection

Claims

1. a main combustion chamber in which a vortex is formed; an auxiliary combustion chamber disposed between the main combustion chamber and the auxiliary combustion chamber via a partition wall; a fuel injection valve that injects fuel into the main combustion chamber; Equipped with The fuel injection valve A first jet that is jetted along the vortex; a second injection directed toward the auxiliary combustion chamber; having Control system for a pre-chamber internal combustion engine.

2. a control device for controlling the fuel injection valve; The control device controls the injection timing of the first injection and the injection timing of the second injection.

2. A control system for an internal combustion engine with a pre-combustion chamber according to claim 1.

3. The control device causes the first injection to start before the second injection.

3. A control system for an internal combustion engine with a pre-combustion chamber according to claim 2.

4. The control device terminates the first injection before the second injection is initiated.

3. A control system for an internal combustion engine with a pre-combustion chamber according to claim 2.

5. Further comprising an intake valve; The control device injects the second injection after the intake valve closes.

3. A control system for an internal combustion engine with a pre-combustion chamber according to claim 2.

6. The fuel injection valve includes a first fuel injection valve disposed on an exhaust side and a second fuel injection valve disposed on an intake side, the control device controls the first fuel injection valve to control the injection timing of the first injection, controlling the second fuel injection valve to control the injection timing of the second injection; 6. A control system for an internal combustion engine with a pre-combustion chamber according to claim 2.

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