Internal combustion engine

Abstract

To provide an internal combustion engine capable of improving exhaust emission during cold start of the internal combustion engine.SOLUTION: A first injection valve injects fuel into an intake path. A second injection valve injects fuel into the intake path, and is located on the upstream side of the first injection valve in the intake path. A second angle formed by a second center line of a second injection region where fuel is injected by the second injection valve and a center line of the intake path is smaller than a first angle formed by a first center line of a first injection region where fuel is injected by the first injection valve and the center line of the intake path. The second injection region is in contact with an inner surface of the intake path.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an internal combustion engine. [Background technology]

[0002] Known examples of inventions relating to conventional internal combustion engines include the internal combustion engine described in Patent Document 1 and the internal combustion engine described in Patent Document 2. The internal combustion engine described in Patent Document 1 is equipped with a first fuel injection valve with a large spray particle size and a second fuel injection valve with a small spray particle size. The internal combustion engine described in Patent Document 1 prevents deterioration of exhaust emissions when the internal combustion engine is started at low temperatures. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-262174 A Summary of the Invention [Problem to be solved by the invention]

[0004] As described above, various internal combustion engines have been proposed for improving exhaust emissions during cold start of the internal combustion engine. SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide an internal combustion engine capable of improving exhaust emissions during cold start of the internal combustion engine. [Means for solving the problem]

[0005] One aspect of the present invention is An internal combustion engine having a combustion chamber and an intake passage connected to the combustion chamber, The internal combustion engine includes an intake valve, a first injector, and a second injector, The first injection valve injects fuel into the intake path, the second injection valve injects fuel into the intake passage and is located upstream of the first injection valve in the intake passage; the intake valve is located downstream of the first injection valve and the second injection valve in the intake path, and opens and closes the intake path;

[0006] a second angle formed by a second center line of a second injection region, into which fuel is injected by the second injection valve, and a center line of the intake passage, is smaller than a first angle formed by a first center line of a first injection region, into which fuel is injected by the first injection valve, and the center line of the intake passage; The second injection area is in contact with an inner surface of the intake passage. It is an internal combustion engine. Effect of the Invention

[0007] According to the present invention, exhaust emissions during cold start of an internal combustion engine can be improved. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of an internal combustion engine 10 . [Diagram 2] FIG. 2 is an enlarged view of the intake path R1. [Diagram 3] FIG. 3 is a timing chart showing the operation of the internal combustion engine 10 during cold start. [Figure 4] FIG. 4 is a timing chart showing the operation of the internal combustion engine 10 after warming up. [Diagram 5] FIG. 5 is a flowchart executed by the control device 100. [Figure 6] FIG. 6 is a diagram showing the state of fuel injection during the injection period T1. [Figure 7] FIG. 7 is a flowchart showing the details of step S2. [Figure 8] FIG. 8 is a map used by the control device 100. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] (Embodiment) [Structure of an internal combustion engine]

[0010] Hereinafter, the structure of an internal combustion engine 10 according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram of the internal combustion engine 10. FIG. 2 is an enlarged view of the intake path R1. In FIG. 1 and FIG. 2, the directions in which the piston 18 moves are defined as the upward direction and the downward direction. However, the upward direction and the downward direction in this specification are directions defined for the convenience of explanation, and may not coincide with the upward direction and the downward direction when the internal combustion engine 10 is actually used.

[0011] The internal combustion engine 10 is used, for example, as a power source for an automobile. The internal combustion engine 10 is, for example, a four-stroke gasoline engine. Note that the internal combustion engine 10 in FIG. 1 is an engine having one cylinder, but generally, an engine having multiple cylinders. When the internal combustion engine 10 is an engine having multiple cylinders, the multiple cylinders are arranged in one row, two rows, or four rows. The internal combustion engine 10 includes an engine body 12, a crankshaft 14, a connecting rod 16, a piston 18, an intake valve 20, an exhaust valve 22, an ignition plug 24, and an ignition coil 26.

[0012] The engine body 12 includes a cylinder block 12a, a cylinder head 12b, and a crankcase 12c. The cylinder block 12a is provided with a cylinder Sy. The cylinder Sy has a cylindrical shape with a central axis extending along the vertical axis.

[0013] The cylinder head 12b is located on the cylinder block 12a. The cylinder head 12b is fixed to the cylinder block 12a. The cylinder head 12b is provided with a combustion chamber Sp. The combustion chamber Sp is located above the cylinder Sy. The combustion chamber Sp is connected to the cylinder Sy.

[0014] The cylinder head 12b is provided with an intake port P1 and an exhaust port P2. The intake port P1 and the exhaust port P2 are connected to the combustion chamber Sp. The intake port P1 is a part of the intake path R1. The intake path R1 is a path through which air or a mixture of fuel and air passes. The exhaust port P2 is a part of the exhaust path R2. The exhaust path R2 is a path through which exhaust gas passes. In this way, the internal combustion engine 10 is provided with the combustion chamber Sp, the intake path R1 connected to the combustion chamber Sp, and the exhaust path R2.

[0015] The crankcase 12c is located below the cylinder block 12a. The crankcase 12c is fixed to the cylinder block 12a. The engine body 12 as described above is made of cast iron.

[0016] The crankshaft 14 is supported by the cylinder block 12a and the crankcase 12c and can rotate about a rotation axis that is perpendicular to the vertical axis. The piston 18 is located in the cylinder Sy. The piston 18 has a cylindrical shape. The piston 18 can move upward and downward.

[0017] The connecting rod 16 connects the crankshaft 14 and the piston 18. As a result, when the crankshaft 14 rotates, the piston 18 moves up and down. The combustion chamber Sp described above is a space surrounded by the piston 18 and the cylinder head 12b when the piston 18 is located at top dead center (TDC).

[0018] The intake valve 20 is supported by the cylinder head 12b. The intake valve 20 is located downstream of a first injector 29 and a second injector 30, which will be described later, in the intake path R1. The intake valve 20 opens and closes the intake path R1. When the intake valve 20 opens the intake path R1, a mixture of fuel and air flows from the intake path R1 into the combustion chamber Sp. The exhaust valve 22 is supported by the cylinder head 12b. The exhaust valve 22 opens and closes the exhaust path R2. When the exhaust valve 22 opens the intake path R1, exhaust flows from the Sp to the exhaust path R2. The intake valve 20 and the exhaust valve 22 as described above are driven by a valve mechanism (not shown).

[0019] The spark plug 24 is fixed to the cylinder head 12b. The spark plug 24 includes a center electrode and a ground electrode. The center electrode and the ground electrode are exposed to the combustion chamber Sp.

[0020] The ignition coil 26 applies a high voltage between the center electrode and the ground electrode of the spark plug 24 based on an ignition signal from the control device 100, which will be described later. This generates a spark between the center electrode and the ground electrode of the spark plug 24, igniting the fuel in the combustion chamber Sp.

[0021] The internal combustion engine 10 further includes an intake manifold 27, an exhaust manifold 28, a first injector 29, a second injector 30, a throttle valve 32, a throttle position sensor 34, an air flow meter 36, a water temperature sensor 38, and a crank angle sensor 40.

[0022] The intake manifold 27 is connected to the cylinder head 12b. The intake manifold 27 is a part of the intake path R1. The exhaust manifold 28 is connected to the cylinder head 12b. The exhaust manifold 28 is a part of the exhaust path R2.

[0023] The first injection valve 29 is fixed to the cylinder head 12b. As shown in FIG. 2, the intake path R1 has a straight section S0 that extends linearly. In this embodiment, the downstream end of the straight section S0 is connected to the combustion chamber Sp. The first injection valve 29 is located in the straight section S0. The first injection valve 29 injects fuel into the intake path R1. The first injection valve 29 has a first injection angle θ1. The first injection angle θ1 will be described below.

[0024] As shown in FIG. 2, the first injection valve 29 has a first injection area A1 having a conical shape. The first injection area A1 has a first center line C1. The first center line C1 extends from the first injection valve 29 toward the downstream of the intake path R1. That is, the first injection valve 29 injects fuel toward the downstream of the intake path R1. When viewed in a direction perpendicular to the first center line C1, an acute angle formed at the apex of the first injection area A1 is defined as a first injection angle θ1. The first injection area A1, the first injection angle θ1, and the first center line C1 are parameters measured when no air flow is generated in the intake path R1.

[0025] The second injector 30 is fixed to the intake manifold 27. The second injector 30 is located upstream of the first injector 29 in the intake path R1. In this embodiment, the second injector 30 is located in a straight section S0. The second injector 30 injects fuel into the intake path R1. As shown in FIG. 2, the second injector 30 has a second injection angle θ2. The definitions of the second injection area A2, the second center line C2, and the second injection angle θ2 are the same as those of the first injection area A1, the first center line C1, and the first injection angle θ1, and therefore will not be described. The second injection angle θ2 of the second injector 30 is greater than the first injection angle θ1 of the first injector 29.

[0026] Here, the center line of the intake path R1 is defined as the center line C0. The direction in which air flows in the intake path R1 is called the intake direction. The center line C0 is a line obtained by connecting the centers of gravity of the figure formed by the intake path R1 in a cross section perpendicular to the intake direction. The second angle θ12 is an angle formed by the second center line C2 of the second injection area A2, where fuel is injected by the second injection valve 30, and the center line C0 of the intake path R1. The first angle θ11 is an angle formed by the first center line C1 of the first injection area A1, where fuel is injected by the first injection valve 29, and the center line C0 of the intake path R1. The second angle θ12 is smaller than the first angle θ11. Here, it is preferable that the second angle θ12 is set so that the projected area of ​​the second injection area A2 onto the inner surface of the intake path R1 is maximized.

[0027] Furthermore, the second injection area A2 is in contact with the inner surface of the intake path R1. That is, the outer edge of the second injection area A2 intersects with the inner surface of the intake path R1. As a result, the fuel injected by the second injection valve 30 adheres to the inner surface of the intake path R1.

[0028] In addition, the average particle size of the fuel injected by the second injector 30 is smaller than the average particle size of the fuel injected by the first injector 29. In other words, the pressure at which the second injector 30 injects fuel is higher than the pressure at which the first injector 29 injects fuel.

[0029] When the internal combustion engine 10 has a plurality of cylinders, the first injector 29 and the second injector 30 are provided for each cylinder.

[0030] As shown in Fig. 1, the throttle valve 32 is located upstream of the first injector 29 and the second injector 30 in the intake path R1. The throttle valve 32 opens and closes the intake path R1 in response to the driver's operation of the accelerator pedal. In this way, the throttle valve 32 adjusts the amount of air supplied to the combustion chamber Sp. The throttle position sensor 34 detects the open / closed state of the throttle valve 32.

[0031] The air flow meter 36 is located in the intake path R1 upstream of the throttle valve 32. The air flow meter 36 detects the amount of air passing through the intake path R1.

[0032] The water temperature sensor 38 is provided in the engine body 12. The water temperature sensor 38 detects the water temperature of the engine body 12. The water temperature is the temperature of the cooling water for the engine body 12.

[0033] The crank angle sensor 40 is provided in the engine body 12. The crank angle sensor 40 detects the rotation angle of the crankshaft 14.

[0034] The internal combustion engine 10 further includes a control device 100. The control device 100 is an ECU (Engine Control Unit). The control device 100 controls the operation of the internal combustion engine 10 based on signals from a throttle position sensor 34, an air flow meter 36, a water temperature sensor 38, and a crank angle sensor 40. Specifically, the control device 100 controls the timing of fuel injection by the first injector 29 and the second injector 30, and the timing of ignition by the spark plug 24. [Operation of the internal combustion engine 10]

[0035] Next, the operation of the internal combustion engine 10 will be described with reference to the drawings. Fig. 3 is a timing chart showing the operation of the internal combustion engine 10 at cold start. Fig. 4 is a timing chart showing the operation of the internal combustion engine 10 after warming up.

[0036] During a cold start shown in Fig. 3, the control device 100 causes the second injection valve 30 to inject fuel during an injection period T1 spanning an exhaust stroke and an intake stroke. During the injection period T1, the first injection valve 29 does not inject fuel. The injection period T1 includes a synchronous injection period Ta and an asynchronous injection period Tb. The synchronous injection period Ta and the asynchronous injection period Tb will be described.

[0037] The synchronous injection is an operation in which the control device 100 causes the first injector 29 and / or the second injector 30 to inject fuel based on a signal from the crank angle sensor 40. The synchronous injection period Ta is a period during which the synchronous injection is performed. On the other hand, the asynchronous injection is an operation in which the control device 100 causes the first injector 29 and / or the second injector 30 to inject fuel without being based on a signal from the crank angle sensor 40. In this embodiment, the asynchronous injection is performed immediately before the synchronous injection during cold start. The asynchronous injection period Tb is a period during which the synchronous injection is performed.

[0038] After warming up as shown in Fig. 4, the control device 100 causes the first injector 29 to inject fuel during an injection period T2 spanning an exhaust stroke and an intake stroke. During the injection period T2, the second injector 30 does not inject fuel. The injection period T2 includes a synchronous injection period Ta.

[0039] Next, the operation performed by the control device 100 will be described with reference to the drawings. Fig. 5 is a flowchart executed by the control device 100. Fig. 6 is a diagram showing the state of fuel injection during the injection period T1. Fig. 7 is a flowchart showing the details of step S2. Fig. 8 is a map used by the control device 100.

[0040] The control device 100 determines whether the water temperature is lower than a first predetermined temperature based on a signal from the water temperature sensor 38 (step S1). In step S1, the control device 100 determines whether or not the engine is in a cold start state. Therefore, the first predetermined temperature is set to the water temperature at the time of cold start. The first predetermined temperature is, for example, 60 degrees. If the water temperature is lower than the first predetermined temperature, the process proceeds to step S2. If the water temperature is equal to or higher than the first predetermined temperature (higher than the first predetermined temperature), the process proceeds to step S3.

[0041] When the water temperature is lower than the first predetermined temperature, the control device 100 performs a first mode fuel injection (step S2). The first mode fuel injection is a fuel injection mode shown in Fig. 3. That is, when the water temperature is lower than the first predetermined temperature, the control device 100 causes the second injection valve 30 to inject fuel. Step S2 will be described below with reference to Figs. 6 and 7.

[0042] The time te in FIG. 6 is the timing when the injection period T1 ends. The time tb is the timing of the bottom dead center. In the "period before the time te in FIG. 6", the second injection valve 30 injects fuel. Then, at "time te", the second injection valve 30 injects the last fuel particle P. It is desirable that this fuel particle P reaches the combustion chamber Sp before the time tb. In the period after the time tb, the piston 18 rises. Therefore, the blowback of the mixture to the intake port P1 occurs. It is preferable that the amount of the mixture blown back is small. Therefore, it is sufficient that the fuel particle P reaches the combustion chamber Sp before the time tb when the blowback of the mixture occurs. Then, the control device 100 may determine the time te of the injection period T1 so that the fuel particle P reaches the combustion chamber Sp before the time tb when the blowback of the mixture occurs.

[0043] Therefore, the velocity of the fuel particle P is defined as v. The distance from the second injector 30 to the combustion chamber Sp is defined as L. In this case, the following formula (1) holds. v(tb-te)>L (1) That is, the time te only needs to satisfy the following formula (2). te <tb-L / v···(2)

[0044] The speed v generally depends on the rotation speed N of the crankshaft 14 and the opening degree φ of the throttle valve 32. That is, as the rotation speed N of the crankshaft 14 increases, the speed v increases. As the opening degree φ of the throttle valve 32 increases, the speed v increases. A storage unit (not shown) stores the map of FIG. 8. The map shows the relationship between the rotation speed Nm, the opening degree φn, and the time tmn. m and n are natural numbers. The map is set by experiments and simulations. The time tmn is the time from the time tt of the top dead center to the time te, as shown in FIG. 3. That is, if the time tmn is determined, the time te is determined.

[0045] The control device 100 calculates the rotation speed N of the crankshaft 14 based on a signal from the crank angle sensor 40 (step S11). Furthermore, the control device 100 calculates the opening degree φ of the throttle valve 32 based on a signal from the throttle position sensor 34 (step S12). Then, the control device 100 determines the time tmn by referring to the map of FIG. 8 based on the rotation speed N of the crankshaft 14 and the opening degree φ of the throttle valve 32 (step S13). This allows the control device 100 to determine the time te. Then, the control device 100 makes the second injector 30 inject fuel so that the fuel injection is completed at the determined time te. Through the above steps S11 to S13, the control device 100 controls the second injector 30 so that the fuel (fuel grain P) injected by the second injector 30 at the timing (time te) when the synchronous injection ends reaches the combustion chamber Sp before the timing (time tb) when the piston 18 is located at the bottom dead center. After that, the process proceeds to step S4.

[0046] If the water temperature is equal to or higher than the first predetermined temperature, the control device 100 performs a second mode fuel injection (step S3). The second mode fuel injection is a fuel injection mode shown in Fig. 4. That is, if the water temperature is higher than the first predetermined temperature, the control device 100 causes the first injector 29 to inject fuel and does not cause the second injector 30 to inject fuel. After this, the process proceeds to step S4.

[0047] In step S4, the control device 100 judges whether or not to end this process (step S4). The control device 100 judges, for example, whether or not the driver has turned off the ignition. If this process is not to be ended, this process returns to step S1. [effect]

[0048] According to the internal combustion engine 10, it is possible to improve exhaust emissions during cold start of the internal combustion engine 10. More specifically, during cold start, fuel is difficult to vaporize. Therefore, in a conventional general internal combustion engine, the amount of fuel injected is increased so that the internal combustion engine can be easily started.

[0049] However, in a port injection type internal combustion engine, fuel adheres to the inner surface of the port and the valve. Because the inner surface of the port is away from the combustion chamber, the temperature of the inner surface of the port does not increase easily. Therefore, the fuel adhering to the port may flow into the combustion chamber in a large amount in a liquid state. In this case, the liquid fuel adheres to the inner surface of the cylinder. Some of this liquid fuel is not burned during the expansion stroke and exhaust stroke, but vaporizes and flows out into the exhaust port. This increases unburned HC and worsens exhaust emissions. This tendency is particularly noticeable when starting the internal combustion engine in a low temperature state.

[0050] Incidentally, an internal combustion engine described in Patent Document 1 is known. The internal combustion engine described in Patent Document 1 is equipped with a first fuel injection valve with a large spray particle size and a second fuel injection valve with a small spray particle size. During cold start, fuel is injected by the second fuel injection valve. The internal combustion engine described in Patent Document 1 as described above can prevent fuel from adhering to the intake port.

[0051] However, in the internal combustion engine described in Patent Document 1, the fuel injection amount is increased during cold start, so a large amount of fuel adheres to the vicinity of the intake valve before the intake valve opens. Therefore, there is still room for improvement in exhaust emissions in the internal combustion engine described in Patent Document 1.

[0052] Therefore, in the internal combustion engine 10, the second angle θ12 formed by the second center line C2 of the second injection area A2 where the fuel is injected by the second injection valve 30 and the center line C0 of the intake passage R1 is smaller than the first angle θ11 formed by the first center line C1 of the first injection area A1 where the fuel is injected by the first injection valve 29 and the center line C0 of the intake passage R1. Furthermore, the second injection area A2 is in contact with the inner surface of the intake passage R1. When the second angle θ12 is reduced in this manner, the second injection area A2 comes in contact with a wide area of ​​the inner surface of the intake passage R1. In particular, the second injection valve 30 is located upstream of the first injection valve 29 in the intake passage R1. Therefore, the distance from the second injection valve 30 to the intake valve 20 is long. Therefore, the fuel injected by the second injection valve 30 is widely and thinly attached to the inner surface of the intake passage R1 in the section from the second injection valve 30 to the intake valve 20. Therefore, the fuel adhering to the inner surface of the intake passage R1 is easily vaporized. When such a second injection valve 30 is used during cold start of the internal combustion engine 10, the generation of unburned HC is suppressed, and exhaust emissions during cold start (especially during start at low temperature) are improved.

[0053] According to the internal combustion engine 10, exhaust emissions during cold start of the internal combustion engine can also be improved for the following reasons. More specifically, the average particle diameter of the fuel injected by the second injector 30 is smaller than the average particle diameter of the fuel injected by the first injector 29. As a result, the fuel injected by the second injector 30 adheres more thinly to the inner surface of the intake path R1 in the section from the second injector 30 to the intake valve 20. Therefore, the fuel adhered to the inner surface of the intake path R1 is more likely to vaporize. When such a second injector 30 is used during cold start of the internal combustion engine 10, the generation of unburned HC is suppressed, and exhaust emissions during cold start (particularly during start at low temperatures) are improved.

[0054] According to the internal combustion engine 10, exhaust emissions during cold start of the internal combustion engine can also be improved for the following reasons. More specifically, the second injection angle θ2 of the second injector 30 is greater than the first injection angle θ1 of the first injector 29. As a result, the fuel injected by the second injector 30 adheres more thinly to the inner surface of the intake path R1 in the section from the second injector 30 to the intake valve 20. Therefore, the fuel adhered to the inner surface of the intake path R1 is more likely to vaporize. When such a second injector 30 is used during cold start of the internal combustion engine 10, the generation of unburned HC is suppressed, and exhaust emissions during cold start (particularly during start at low temperatures) are improved. In the internal combustion engine 10, the second injection valve 30 is located in the straight section S0. This makes it easier for the fuel injected by the second injection valve 30 to reach the combustion chamber Sp.

[0055] According to the internal combustion engine 10, the control device 100 controls the second injector 30 so that the fuel (fuel grain P) injected by the second injector 30 at the timing (time te) when the synchronous injection ends reaches the combustion chamber Sp before the timing (time tb) when the piston 18 is at the bottom dead center. As a result, at the time tb when the blow-back of the mixture starts, the flow of the mixture containing the fuel injected by the second injector 30 into the combustion chamber Sp is completed. As a result, the amount of the mixture blown back is reduced.

[0056] According to the internal combustion engine 10, the second injection valve 30 is fixed to the intake manifold 27. This increases the distance from the second injection valve 30 to the intake valve 20. As a result, the fuel injected by the second injection valve 30 adheres more thinly to the inner surface of the intake path R1 in the section from the second injection valve 30 to the intake valve 20. Therefore, the fuel adhered to the inner surface of the intake path R1 is more likely to vaporize. When such a second injection valve 30 is used during a cold start of the internal combustion engine 10, the generation of unburned HC is suppressed, and exhaust emissions during cold start (particularly during start at low temperatures) are improved.

[0057] (Other embodiments) The internal combustion engine according to the present invention is not limited to the internal combustion engine 10, and can be modified within the scope of the invention.

[0058] The fuel may be a fuel other than gasoline. The fuel may be a hydrocarbon fuel other than gasoline, or may be an alcohol fuel such as bioethanol fuel.

[0059] The synchronous injection period Ta of the second injector 30 may be shorter than the synchronous injection period (injection period T2) of the first injector 29. The pressure at which the second injector 30 injects fuel is higher than the pressure at which the first injector 29 injects fuel. This is because the second injector 30 can inject more fuel in a short period of time.

[0060] It should be noted that the first injector 29 is fixed to the cylinder head 12b. However, the first injector 29 may be fixed to the intake manifold 27. The second injector 30 is fixed to the intake manifold 27. However, the second injector 30 may be fixed to the cylinder head 12b.

[0061] In addition, the first injector 29 may inject fuel together with the second injector 30 during the injection period T1.

[0062] The second injection valve 30 may be located in a curved section of the intake path R1, instead of in the straight section S0.

[0063] The internal combustion engine 10 may be equipped with an oil temperature sensor. The oil temperature sensor detects the oil temperature of the internal combustion engine 10. The oil noise is the temperature of the lubricating oil of the internal combustion engine 10. When the oil temperature is lower than a second predetermined temperature, the control device 100 causes the second injection valve 30 to inject fuel, and when the oil temperature is higher than the second predetermined temperature, the control device 100 causes the first injection valve 29 to inject fuel and does not cause the second injection valve 30 to inject fuel. The second injection angle θ2 of the second injector 30 may be equal to or smaller than the first injection angle θ1 of the first injector 29. The average particle diameter of the fuel injected by the second injector 30 may be equal to or larger than the average particle diameter of the fuel injected by the first injector 29 .

[0064] The control device 100 determines the time tmn based on the rotation speed N of the crankshaft 14 and the opening degree φ of the throttle valve 32. However, the control device 100 may determine the time tmn based on the rotation speed N of the crankshaft 14, the opening degree φ of the throttle valve 32, and other parameters. The other parameters are, for example, the opening degree of the accelerator pedal and the amount of air flowing through the intake path R1.

[0065] The automobile may be a four-wheeled automobile, a three-wheeled automobile, or a two-wheeled automobile. A two-wheeled automobile is a leaning vehicle in which the body leans in the same direction as the direction of travel around the corner. A three-wheeled automobile may be a leaning vehicle, or may be a vehicle that rolls in the opposite direction to the direction of travel around the corner.

[0066] The internal combustion engine 10 may be used as a power source for vehicles other than automobiles. Also, the internal combustion engine 10 may be used as a generator for generating electric power for an EV (Electric Vehicle). [Explanation of symbols]

[0067] 10: Internal combustion engine 12: Main body of the engine 12a: Cylinder block 12b: Cylinder head 12c: Crankcase 14: Crankshaft 16: Connecting rod 18: Piston 20: Intake valve 22: Exhaust valve 24: Spark plug 26: Ignition coil 27: Intake manifold 28: Exhaust manifold 29: First injector 30: Second injector 32: Throttle valve 34: Throttle position sensor 36: Air flow meter 38: Water temperature sensor 40: Crank angle sensor 100: Control device A1: 1st injection area A2:Second injection area C0: Center line C1: 1st center line C2: 2nd center line P: Fuel grain P1: Intake port P2: Exhaust port R1: Intake path R2: Exhaust route S0: Straight section Sp: Combustion chamber Sy: Cylinder T1, T2: Injection period Ta: Synchronous injection period Tb: Asynchronous injection period

Claims

1. An internal combustion engine having a combustion chamber and an intake passage connected to the combustion chamber, The internal combustion engine includes an intake valve, a first injector, and a second injector. The first injection valve injects fuel into the intake path, the second injection valve injects fuel into the intake passage and is located upstream of the first injection valve in the intake passage, the intake valve is located downstream of the first injection valve and the second injection valve in the intake path, and opens and closes the intake path; a second angle formed by a second center line of a second injection region, into which fuel is injected by the second injection valve, and a center line of the intake passage, is smaller than a first angle formed by a first center line of a first injection region, into which fuel is injected by the first injection valve, and the center line of the intake passage; The second injection area is in contact with an inner surface of the intake passage. Internal combustion engine.

2. The intake path has a straight section that extends linearly, The second injection valve is located in the straight section.

2. The internal combustion engine of claim 1.

3. The internal combustion engine further includes a control device, The control device controls the second injection valve so that the fuel injected by the second injection valve at the timing when the synchronous injection ends reaches the combustion chamber before the timing when the piston is located at the bottom dead center.

3. An internal combustion engine according to claim 1 or 2.

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