Internal combustion engine with sub-combustion chamber

Abstract

To provide an internal combustion engine with an auxiliary combustion chamber excellent in ignitability.SOLUTION: An internal combustion engine 1 includes a main combustion chamber 41, an auxiliary combustion chamber 43 provided at the upper center in the main combustion chamber 41, a first intake port 2a and a second intake port 2b for supplying intake air into the main combustion chamber 41, a first injector 60 provided in the first intake port 2a, and a second injector 61 provided in the second intake port 2b. The first injector 60 is arranged so that a first injection hole 62 faces the center in the main combustion chamber 41, and injects fuel having penetration force higher than the second injector 61.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an internal combustion engine having a sub-combustion chamber in a main combustion chamber.

Background Art

[0002] Many internal combustion engines such as gasoline engines used in automobiles have an injector (fuel injection valve) that injects fuel into an intake passage or a combustion chamber, and an ignition device (ignition plug) disposed facing the combustion chamber in a cylinder. Furthermore, Patent Document 1 discloses an internal combustion engine provided with a sub-combustion chamber in a combustion chamber (main combustion chamber). In the internal combustion engine described in Patent Document 1, an air-fuel mixture having a relatively high fuel concentration is supplied into the sub-combustion chamber, and the air-fuel mixture in the sub-combustion chamber is ignited by an ignition device, so that flames are ejected from the sub-combustion chamber into the main combustion chamber to burn the air-fuel mixture in the main combustion chamber. As a result, the ignitability of the air-fuel mixture in the main combustion chamber can be improved to improve the output of the internal combustion engine, or the fuel concentration in the main combustion chamber can be lowered to improve the fuel efficiency.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in an internal combustion engine having a sub-combustion chamber in the main combustion chamber as described above, it is difficult for an injector that injects fuel into an intake passage (intake port) to appropriately supply a thick air-fuel mixture to the sub-combustion chamber and a relatively thin air-fuel mixture to the main combustion chamber due to the influence of the airflow associated with intake and exhaust. In particular, a strong airflow is generated in the combustion chamber, and the strength of the airflow changes depending on the operating state of the internal combustion engine. Therefore, it is difficult to efficiently supply fuel to the sub-combustion chamber and appropriately increase the fuel concentration over a wide operating range.

[0005] The present invention was made to solve these problems, and aims to provide an internal combustion engine with a sub-combustion chamber that has a sub-combustion chamber in the main combustion chamber and an injector provided in the intake port, by efficiently supplying fuel from the injector to the sub-combustion chamber to provide an internal combustion engine with excellent ignition performance. [Means for solving the problem]

[0006] To achieve the above objective, the internal combustion engine with a sub-combustion chamber of the present invention comprises a main combustion chamber and an internal combustion chamber within the main combustion chamber. central A sub-combustion chamber provided therein, a first intake port and a second intake port that supply intake air to the main combustion chamber, a first injector provided in the first intake port, and a second injector provided in the second intake port, A control unit that controls the first injector and the second injector, An internal combustion engine having the following: The first injector is provided such that the fuel injection hole faces the center of the main combustion chamber and injects fuel with higher penetrating power than the second injector. Furthermore, the control unit controls the first injector to inject fuel with lower penetration power compared to the low-load operating region, which has a lower load than the high-load operating region, in a predetermined high-load operating region of the internal combustion engine with a sub-combustion chamber. It is characterized by the following:

[0007] This results in the main combustion chamber central The first injector supplies fuel with high penetration power to the sub-combustion chamber located in the sub-combustion chamber. Therefore, fuel can be efficiently supplied to the sub-combustion chamber from the first injector, increasing the fuel concentration in the sub-combustion chamber and improving ignition performance. 。

[0008] Also, In high-load operating conditions, the injection of highly penetrating fuel from the first injector is suppressed, reducing the intensity of the flame in the sub-combustion chamber. Consequently, the flame propagating from the sub-combustion chamber to the main combustion chamber is prevented from becoming excessively strong, thus protecting the internal combustion engine. Preferably, the first injector has an injector valve that controls the fuel injection amount by changing the lift amount and lift time, and the control unit may reduce the lift amount and increase the lift time of the injector valve of the first injector to weaken the penetrating force of the fuel injection of the first injector.

[0009] This makes it easy to reduce the penetration force of fuel injection from the first injector by controlling the injector valve of the first injector. Preferably, when the control unit reduces the penetration force of the first injector, it controls the start of the lift of the injector valve to be earlier than before the penetration force was reduced. This allows the amount of fuel injected per unit time from the first injector to be reduced compared to before the penetration force was weakened, thereby reducing the penetration force, while also allowing the timing of the end of fuel injection to be kept constant regardless of the change in penetration force.

[0010] Preferably, the system includes a control unit that controls the first injector and the second injector, and the control unit can switch between a first injection mode in which fuel with higher penetration power than that of the second injector is injected from the first injector, and a second injection mode in which fuel with higher penetration power than that of the first injector is injected from the second injector, and it is preferable to switch to the second injection mode when the first injection mode is performed for a predetermined period of time.

[0011] As a result, a second injection mode, in which a fuel with high penetration power is injected, is switched between the first and second injectors at predetermined intervals. This suppresses the fuel injected from the injectors from adhering unevenly to either the first or second intake port, and promotes the evaporation of the adhering fuel. Preferably, the first injector has a first injection hole and a second injection hole as fuel injection holes, the first injection hole is provided to face the sub-combustion chamber and injects fuel with higher penetration power than the second injector, and the second injection hole is provided to face the main combustion chamber and injects fuel with lower penetration power than the first injection hole.

[0012] As a result, fuel is injected not only from the second injector but also from the second injection hole of the first injector towards the main combustion chamber, allowing fuel to be injected more evenly throughout the main combustion chamber, promoting the cooling effect on the walls of the main combustion chamber and suppressing knocking. Furthermore, the internal combustion engine with a sub-combustion chamber of the present invention is an internal combustion engine having a main combustion chamber, a sub-combustion chamber provided in the main combustion chamber, a first intake port and a second intake port for supplying intake air to the main combustion chamber, a first injector provided in the first intake port, and a second injector provided in the second intake port, wherein the first injector and the second injector are characterized in that they have a first injection hole provided so as to face the center of the main combustion chamber, and a second injection hole provided so as to face the main combustion chamber and for injecting fuel with lower penetrating power than the first injection hole.

[0013] As a result, high-penetration fuel is injected from the first injection holes of the first and second injectors into the sub-combustion chamber located within the main combustion chamber, while low-penetration fuel is injected into the main combustion chamber from the second injection holes. Therefore, fuel can be efficiently supplied to the sub-combustion chamber from the first and second injectors, increasing the fuel concentration in the sub-combustion chamber and improving ignition performance. [Effects of the Invention]

[0014] According to the internal combustion engine with a sub-combustion chamber of the present invention, sufficient fuel can be supplied to the sub-combustion chamber to generate a strong flame, thereby improving ignition in the main combustion chamber. This promotes combustion in the main combustion chamber, improving output while suppressing a decrease in fuel efficiency. [Brief explanation of the drawing]

[0015] [Figure 1] This is a diagram showing the configuration of the intake and exhaust system of an internal combustion engine according to one embodiment of the present invention. [Figure 2] This is a top view showing the positions of the intake and exhaust ports and spark plug in the internal combustion engine of the first embodiment. [Figure 3]It is an image diagram of fuel injection in a low load operation region of an internal combustion engine according to the first embodiment. [Figure 4] It is a timing diagram showing an example of injection timing and injection amount in a low load operation region of an internal combustion engine according to the first embodiment. [Figure 5] It is an image diagram of fuel injection supply in a high load operation region of an internal combustion engine according to the first embodiment. [Figure 6] It is a timing diagram showing an example of injection timing and injection amount in a high load operation region of an internal combustion engine according to the first embodiment. [Figure 7] It is an image diagram of fuel injection supply in an internal combustion engine according to the second embodiment. [Figure 8] It is a perspective view showing an example of the structure of a fuel injection hole of an injector. [Figure 9] It is an image diagram of fuel injection supply in an internal combustion engine according to the third embodiment. [Figure 10] It is an image diagram of fuel injection supply in an internal combustion engine according to a reference embodiment.

Embodiments for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described based on the drawings. FIG. 1 is a configuration diagram of an intake and exhaust system of an internal combustion engine 1 according to an embodiment of the present invention. As shown in FIG. 1, the internal combustion engine 1 (internal combustion engine with a sub - combustion chamber) of the present embodiment is a port - injection gasoline engine having an injector 3 that injects gasoline as fuel into an intake port 2.

[0017] In the intake passage 5 of the internal combustion engine 1 of the present embodiment, an air cleaner 6, an inter - cooler 7, and a throttle valve 8 are provided along the intake flow toward the intake port 2. In the exhaust passage 11 of the internal combustion engine 1, an upstream exhaust purification catalyst 12 and a downstream exhaust purification catalyst 13 are provided along the exhaust flow from the exhaust port 31. Further, the internal combustion engine 1 is provided with a supercharger (turbocharger) 15 and an EGR system 16.

[0018] The supercharger 15 includes a turbine (not shown) which is rotationally driven by the exhaust gas, and a compressor (not shown) which rotates in conjunction with the turbine and compresses the intake air in the intake passage 5. The turbine is located in the exhaust passage 11 between the exhaust port 31 and the upstream exhaust gas purification catalyst 12, and the compressor is located in the intake passage 5 between the air cleaner 6 and the intercooler 7. The EGR system 16 includes an EGR passage 20 that connects the exhaust passage 11 and the intake passage 5 of the internal combustion engine 1, an EGR valve 21 that changes the flow area of ​​the EGR passage 20, and an EGR cooler 22 that cools the exhaust gas passing through the EGR passage 20. The EGR passage 20 connects the exhaust passage 11 between the upstream exhaust purification catalyst 12 and the downstream exhaust purification catalyst 13, and the intake passage 5 between the air cleaner 6 and the compressor of the supercharger 15.

[0019] Furthermore, the exhaust passage 11 is equipped with a wastegate valve 25 that opens and closes a passage that bypasses the turbine of the supercharger 15. The intake passage 5 is equipped with a recirculation valve 26 that opens and closes a passage that bypasses the compressor of the supercharger 15. Figure 2 is a top view showing the positions of the intake and exhaust ports 2, 31 and the spark plug 35 in the internal combustion engine 1 of the first embodiment.

[0020] As shown in Figure 2, the internal combustion engine 1 is equipped with two intake ports 2 and two exhaust ports 31 for each cylinder 30. In addition, each of the two intake ports 2 is equipped with an intake valve 32, and each of the two exhaust ports 31 is equipped with an exhaust valve 33. Each intake port 2 has one injector 3, meaning there are two injectors for each cylinder 30.

[0021] In the upper part of cylinder 30 of the internal combustion engine 1 (cylinder head 34), two intake ports 2 are arranged side by side on one side of the center, and two exhaust ports 31 are arranged side by side on the other side. As shown in Figures 1 and 2, a spark plug 35 is provided in the center of the cylinder head 34. The cylinder head 34 is provided with a partition wall 42 that surrounds the central electrode of the spark plug 35.

[0022] Inside the cylinder 30 is a main combustion chamber 41, which is a roughly cylindrical space surrounded by the cylinder, cylinder head 34, and piston formed in the cylinder block. Furthermore, the space in the upper central part of the main combustion chamber 41 is provided as a sub-combustion chamber 43, surrounded by a partition wall 42. Multiple communication holes 44 are opened in the partition wall 42, and the main combustion chamber 41 and the sub-combustion chamber 43 are in communication with each other through the communication holes 44.

[0023] The internal combustion engine 1 is operated and controlled by a control unit 50 (control unit). The control unit 50 consists of an output device, a memory device (ROM, RAM, non-volatile RAM, etc.), a central processing unit (CPU), etc. The control unit 50 receives input such as crank angle, intake air temperature, exhaust air temperature, and EGR gas temperature, and operates and controls the injectors 3, spark plugs 35, throttle valve 8, EGR valve 21, wastegate valve 25, recirculation valve 26, etc.

[0024] Figure 3 is an illustrative diagram of fuel injection supply in the low-load operating region of the internal combustion engine 1 of the first embodiment. Figure 4 is a timing diagram showing an example of injection timing (crank angle) and injection amount in the low-load operating region of the internal combustion engine 1 of the first embodiment. In the internal combustion engine 1 of the first embodiment, of the two injectors 3 provided in each of the two intake ports 2, the first injector 60 provided in one of the first intake ports 2a has a first injection hole 62 that injects fuel toward the center of the cylinder 30, i.e., the vicinity of the sub-combustion chamber 43. That is, the first injection hole 62 is provided so as to face the center of the cylinder 30, or in other words, so as to coincide with the center of the cylinder 30. The second injector 61 provided in the other second intake port 2b has a second injection hole 63 that injects fuel toward the main combustion chamber 41. It is preferable that the second injection hole 63 is provided in such a orientation that the injected fuel is carried by the airflow and diffused evenly within the cylinder 30.

[0025] The first injection hole 62 of the first injector 60 only needs to be configured so that the injected fuel flows mainly into the sub-combustion chamber 43. It may be configured to inject directly into the sub-combustion chamber 43, or it may be configured so that the injected fuel flows indirectly into the sub-combustion chamber 43. Furthermore, the sub-combustion chamber 43 may be slightly offset from the center of the main combustion chamber 41. That is, even if the sub-combustion chamber 43 is located offset to one side from the vicinity of the center of the main combustion chamber 41, the other end of the sub-combustion chamber 43 is located near the center of the main combustion chamber 41, i.e., in a place where the fuel concentration is high due to the fuel injected from the first injector 60, so fuel is supplied into the sub-chamber during the compression stroke.

[0026] Furthermore, the first injection port 62 is set to inject fuel with higher penetration power than the second injection port 63. High penetration power fuel injection is injection that is less affected by intake airflow and has a high ability to deliver fuel to the desired region (sub-combustion chamber 43). For example, the first injection port 62 can be made smaller than the second injection port 63, or the fuel injection pressure from the first injection port 62 can be set higher than that from the second injection port 63, so that the fuel injected from the first injection port 62 is injected with more force (higher penetration power) than the fuel injected from the second injection port 63.

[0027] The second injector 61 injects homogeneous fine-particle premixed fuel into the main combustion chamber 41 through the second injection hole 63. Furthermore, it is preferable that the fuel injected from the first injection hole 62 does not directly hit the shaft of the intake valve 32 or the wall surface of the cylinder 30. As shown in Figures 3 and 4, in the internal combustion engine 1 of the first embodiment, in the low-load operating region where the load is below a predetermined value (for example, the operating region where supercharging by the supercharger 15 is not possible), the second injector 61 injects fuel from the second injection hole 63 from the end of the exhaust stroke and continues fuel injection across the intake stroke.

[0028] The first injector 60 injects fuel from the first injection hole 62 in a shorter time during the intake stroke. For example, the amount of fuel injected per unit time from the first injection hole 62 of the first injector 60 is greater than the amount of fuel injected per unit time from the second injection hole 63 of the second injector 61, and the fuel injection time from the first injection hole 62 of the first injector 60 is shorter than the fuel injection time from the second injection hole 63 of the second injector 61.

[0029] Furthermore, it is preferable to make the timing of the end of fuel injection from the first injection hole 62 of the first injector 60 and the timing of the end of fuel injection from the second injection hole 63 of the second injector 61 approximately the same. Figure 5 is an illustrative diagram of fuel injection supply in the high-load operating region of the internal combustion engine 1 of the first embodiment. Figure 6 is a timing diagram showing an example of injection timing and injection amount in the high-load operating region of the internal combustion engine 1 of the first embodiment.

[0030] As shown in Figures 5 and 6, in the internal combustion engine 1 of the first embodiment, in the high-load operating region where the load is above a predetermined value (for example, the operating region in which supercharging by the supercharger 15 is possible), the second injector 61 injects fuel from the second injection hole 63 from the end of the exhaust stroke, similar to the low-load operating region, and injects fuel across the intake stroke. However, the amount of fuel injected per unit time is set to increase as the load increases, and more specifically, the opening of the throttle valve 8 is controlled as the load increases, and the amount of fuel injected is controlled according to the opening of the throttle valve 8. In this embodiment, the fuel injection amounts of the first injector 60 and the second injector 61 are controlled so that the air-fuel ratio in the main combustion chamber 41 is stoichiometric. The first injector 60 injects fuel from the first injection hole 62 from the end of the exhaust stroke and injects fuel across the intake stroke. The fuel injection start timings for the first injector 60 and the second injector 61 are approximately the same, and the fuel injection end timings are also approximately the same, or the fuel injection from the first injector 60 may be delayed until later than that of the second injector 61 depending on the load.

[0031] As described above, the internal combustion engine 1 of the first embodiment is equipped with a sub-combustion chamber 43 surrounded by a partition wall 42 in the upper central part of the main combustion chamber 41. The partition wall 42 is provided with a communication hole 44 that connects the main combustion chamber 41 and the sub-combustion chamber 43, and the spark plug 35 ignites the air-fuel mixture in the sub-combustion chamber 43. As a result, the flame generated by ignition in the sub-combustion chamber 43 is ejected from the communication hole 44 and propagates to the main combustion chamber 41, efficiently burning the air-fuel mixture in the main combustion chamber 41.

[0032] Each cylinder 30 of the internal combustion engine has two intake ports 2 (2a, 2b), and injectors 3 (60, 61) are provided at intake ports 2a and 2b, respectively. The first injection hole 62 of one of the first injectors 60 is positioned to face the center of the main combustion chamber 41. Fuel is injected from the other second injector 61 toward the main combustion chamber 41. In the low-load operating range of the internal combustion engine 1, the first injection hole 62 of the first injector 60 injects fuel with higher penetration power than the fuel injected from the second injector 61.

[0033] This allows fuel to be efficiently supplied from the first injector to the sub-combustion chamber 43 located in the upper center of the main combustion chamber 41. Therefore, sufficient fuel can be supplied to the sub-combustion chamber 43, increasing the fuel concentration (isovolume) in the sub-combustion chamber 43 and improving ignition. Furthermore, the propagation of the flame from the sub-combustion chamber 43 allows the fuel-air mixture in the main combustion chamber 41 to burn stably and efficiently.

[0034] In the high-load operating range, the first injector 60 injects fuel with low penetration power from the first injection hole 62, similar to the second injector 61. This suppresses the supply of fuel to the sub-combustion chamber 43, thereby preventing the generation of strong flames in the sub-combustion chamber 43 and protecting the cylinder 30. In the high-load operating range, the first injector 60 and the second injector 61 inject more fuel in response to the load, and the overall fuel concentration in the cylinder 30 increases, so ignition can be ensured even without supplying fuel with high penetration power to the sub-combustion chamber 43 from the first injector 60.

[0035] In the high-load operating range, the fuel injection from the first injector 60 is performed by reducing the lift amount of the injector valve of the first injector 60 to reduce the fuel injection amount per unit time and increasing the lift time to increase the fuel injection time, compared to the fuel injection from the first injector 60 in the low-load operating range. This makes it easy to weaken the penetration force of the fuel injection from the first injector 60 in the high-load operating range.

[0036] Furthermore, in the high-load operating range, the lift start of the injector valve of the first injector 60, i.e., the start of fuel injection from the first injector 60, is advanced compared to the low-load operating range, thereby increasing the lift time. This reduces the amount of fuel injected per unit time from the first injector 60, thereby weakening the penetration force, and also makes it possible to make the fuel injection termination timing of the first injector 60 and the second injector 61 the same in both the high-load and low-load operating ranges. By making the fuel injection termination timing of the first injector 60 and the second injector 61 the same regardless of the load, the fuel supply termination timing can be appropriately set in relation to the opening and closing timing of the intake valve 32 and the exhaust valve 33, and the ignition timing.

[0037] Other embodiments of the present invention will be described below, but only the differences from the first embodiment will be described. Figure 7 is an illustrative diagram of the fuel injection supply in the internal combustion engine 70 of the second embodiment. Figure 8 is a perspective view showing an example of the structure of the fuel injection port of the first injector 60. As shown in Figures 7 and 8, in the internal combustion engine 70 of the second embodiment, the first injector 60 is provided with an injection hole for injecting fuel into the center of the cylinder 30 and an injection hole for injecting fuel toward the main combustion chamber 41. That is, of the two injectors 3 provided in each of the two intake ports 2, the first injector 60 provided in one of the first intake ports 2a has a first injection hole 62 for injecting fuel toward the center of the cylinder 30 and a second injection hole 63 for injecting fuel toward the main combustion chamber 41. The first injection hole 62 of the first injector 60 is positioned to face the center of the cylinder 30, and the second injection hole 63 of the first injector 60 is positioned to face the side wall of the cylinder 30. In the low-load operating range, fuel is injected from both the first injection hole 62 and the second injection hole 63. This makes it possible to supply fuel to the entire main combustion chamber 41 with minimal unevenness. Therefore, the cooling effect on the wall surface of the main combustion chamber 41 can be promoted and knocking can be suppressed. In the high-load operating range, fuel injection from the first injection hole 62 of the first injector 60 may be stopped and fuel injection may be performed only from the second injection hole 63, or the penetrating force of fuel injection from the first injection hole 62 may be reduced by reducing the lift amount of the injector valve of the first injector 60.

[0038] Figure 9 shows an internal combustion engine of the third embodiment. 80 This is an illustrative diagram of fuel injection supply in the system. Note that in Figure 9 and Figure 10, which will be described later, a fuel injection with high penetration power is used. solid line The arrows indicate the penetration power, and the dashed arrows indicate fuel injections with low penetration power. Third Embodiment of Internal Combustion Engine 80 Next, injectors 60a and 60b, each having a first injection hole 62 similar to the first injector 60 of the first embodiment, are placed at both of the two intake ports 2a and 2b.

[0039] The control unit 50 then periodically switches between a first injection mode, in which a fuel with high penetration power is injected from the first injector 60a towards the sub-combustion chamber 43, and a second injection mode, in which a fuel with high penetration power is injected from the second injector 60b towards the sub-combustion chamber 43, when injecting fuel from the first injection hole 62 towards the sub-combustion chamber 43. Specifically, in the first injection mode, the lift amount of the injector valve of the second injector 60b is reduced and the lift time is increased, thereby making the fuel injected from the first injection hole 62 of the first injector 60a have higher penetration power than the fuel injected from the first injection hole 62 of the second injector 60b. Similarly, in the second injection mode, the lift amount of the injector valve of the first injector 60a is reduced and the lift time is increased, thereby making the fuel injected from the first injection hole 62 of the first injector 60a have lower penetration power than the fuel injected from the first injection hole 62 of the second injector 60b. For example, the system can be switched after a predetermined engine operating time, after a predetermined number of injections from the first injection hole 62, or after a predetermined cumulative value of the fuel injection amount from the first injection hole 62. In the third embodiment, fuel from the injector with lower penetration power, i.e., the second injector 60b in the first injection mode and the first injector 60a in the second injection mode, is also injected towards the sub-combustion chamber 43 (center of cylinder 30). However, because these fuels have low penetration power, they diffuse and are supplied to the entire main combustion chamber 41 with minimal unevenness.

[0040] This results in the internal combustion engine of the third embodiment. 80 So, the injection of fuel for the sub-combustion chamber 43 The injector is periodically switched between the first injector 60a and the second injector 60b. Therefore, the injection is biased towards either the first intake port 2a or the second intake port 2b. This can suppress the adhesion of fuel injected from cubators 60a and 60b. This promotes the evaporation of fuel adhering to the first intake port 2a and the second intake port 2b, thereby stimulating the internal combustion engine This can improve the exhaust performance and fuel efficiency of the Kan 70. Furthermore, the third embodiment is the first indicator Injector 60a and second injector 60b are similar to the first injector 60 of the second embodiment. The injectors 60a and 60b having a first injection hole 62 and a second injection hole 63 may also be used. In this case, in the first injection mode, fuel is injected from the first injection hole 62 of the second injector 60b. You may prohibit the injection of fuel, or reduce the lift amount of the injector valve. By increasing the time, the fuel injected from the first injection hole 62 of the second injector 60b The penetrating force may be reduced to approximately the same level as the fuel injected from the first injection port 62.

[0041] Figure 10 shows Reference form internal combustion engine 90 This is an illustrative diagram of the fuel injection supply in the system. As shown in Figure 10, Reference form In the internal combustion engine 90, as in the internal combustion engine 70 of the second embodiment, injectors 60 (60a, 60b) having first injection holes 62 and second injection holes 63 are arranged in both of the two intake ports 2a and 2b. Then, for example in the low-load operating region, fuel is supplied to the sub-combustion chamber 43 by high-penetration injection from the first injection holes 62 of each injector and 60a, 60b, and fuel is supplied to the main combustion chamber 41 by low-penetration injection from the second injection holes 63 of each injector 60a, 60b.

[0042] As a result, in the low-load operating range, sufficient fuel is supplied to the sub-combustion chamber 43 to improve ignition performance, and fuel can be supplied to the main combustion chamber 41 evenly throughout the entire chamber with minimal unevenness. The present invention is not limited to the embodiments described above. For example, in the above embodiments, the detailed structure of each injector and the inside of the cylinder of the internal combustion engine may be modified as appropriate. Furthermore, the internal combustion engine of the present invention can be applied to various types of internal combustion engines, such as those used for driving automobiles. [Explanation of Symbols]

[0043] 1, 70, 80, 90 Internal Combustion Engines 2a First intake port 2b Second intake port 41 Main combustion chamber 43. Sub-combustion chamber 50 Control Unit (Control Section) 60, 60a First injector 61, 60b Second injector 62 1st injection hole (fuel injection hole) 63 2nd injection hole (fuel injection hole)

Claims

1. The main combustion chamber, A sub-combustion chamber is provided in the center of the main combustion chamber, A first intake port and a second intake port that supply intake air to the main combustion chamber, A first injector provided in the first intake port, and a second injector provided in the second intake port, An internal combustion engine with a sub-combustion chamber, having a control unit for controlling the first injector and the second injector, The first injector is provided such that its fuel injection port faces the center of the main combustion chamber, and it injects fuel with higher penetration power than the second injector. The control unit controls the first injector to inject fuel with lower penetration power compared to the low-load operating region, which has a lower load than the high-load operating region, in a predetermined high-load operating region of the internal combustion engine with a sub-combustion chamber. An internal combustion engine with a secondary combustion chamber, characterized by the features described above.

2. The first injector has an injector valve that controls the fuel injection amount by changing the lift amount and lift time, The control unit, By reducing the lift amount of the injector valve of the first injector and increasing the lift time, the penetrating force of the fuel injection of the first injector is weakened. An internal combustion engine with a sub-combustion chamber as described in claim 1.

3. The control unit, When reducing the penetration force of the first injector, the injector valve is controlled to start lifting earlier than before the penetration force was reduced. The internal combustion engine with a sub-combustion chamber according to claim 2.

4. The system includes a control unit that controls the operation of the first injector and the second injector, The control unit can switch between a first injection mode in which fuel with higher penetration power than that of the second injector is injected from the first injector, and a second injection mode in which fuel with higher penetration power than that of the first injector is injected from the second injector. When the first injection mode is performed for a predetermined period of time, the system switches to the second injection mode. An internal combustion engine with a sub-combustion chamber as described in claim 1.

5. The first injector has a first injection hole and a second injection hole as fuel injection holes, The first injection port is provided so as to face the sub-combustion chamber and injects fuel with higher penetration power than the second injector. The second injection port is provided so as to face the main combustion chamber and injects fuel with lower penetrating power than the first injection port. An internal combustion engine with a sub-combustion chamber as described in claim 1.

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