Internal combustion engine system

Abstract

The object of the present invention is to provide an internal combustion engine system that can reduce the amount of pressure increase in the intake path when backfire occurs. [Solution] The internal combustion engine system according to the present invention comprises an internal combustion engine, an intake path, a detonation path, a throttle valve, a detonation valve, and a control device. The intake path is connected to the internal combustion engine. The throttle valve is provided in the intake path. The detonation path is connected to the intake path between the internal combustion engine and the throttle valve. The detonation valve is provided in the detonation path. When backfire occurs, the opening of the detonation valve increases, and the control device changes the opening of the throttle valve.

Description

Technical Field

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

Background Art

[0002] As an invention related to a conventional internal combustion engine system, for example, an exhaust gas recirculation valve described in Patent Document 1 is known. This exhaust gas recirculation valve has a function as a relief valve. Specifically, when backfire occurs, the exhaust gas recirculation valve opens by the pressure in the intake passage. Thereby, the exhaust gas recirculation valve described in Patent Document 1 can reduce the pressure in the intake passage.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As described above, there is a need for an internal combustion engine system that can reduce the amount of increase in the pressure of the intake passage when backfire occurs.

[0005] Therefore, an object of the present invention is to provide an internal combustion engine system that can reduce the amount of increase in the pressure of the intake passage when backfire occurs.

Means for Solving the Problems

[0006] The first aspect is that the internal combustion engine system includes an internal combustion engine, an intake passage, an explosion relief passage, a throttle valve, an explosion relief valve, and a control device, the intake passage is connected to the internal combustion engine, the throttle valve is provided in the intake passage, The explosion path is connected to the intake path between the internal combustion engine and the throttle valve. The aforementioned detonation valve is provided in the detonation path, When a backfire occurs, the opening of the detonation valve increases, and the control device changes the opening of the throttle valve. It is an internal combustion engine system.

[0007] The second aspect is, The aforementioned internal combustion engine system further includes a pressure sensor. The pressure sensor outputs a pressure signal indicating the intake path pressure in the intake path between the internal combustion engine and the throttle valve. The control device determines whether or not backfire has occurred by determining, based on the pressure signal, whether or not the intake path pressure has become greater than the first pressure. This is the internal combustion engine system described on the first side.

[0008] The third aspect is, The second pressure is greater than the first pressure. The third pressure is greater than the second pressure. If the intake path pressure is greater than the second pressure and less than the third pressure, the control device reduces the opening of the throttle valve and increases the opening of the detonation valve. If the intake path pressure is greater than the third pressure, the control device increases the opening of the throttle valve and also increases the opening of the detonation valve. This is the internal combustion engine system described on the second side.

[0009] The fourth aspect is, The aforementioned internal combustion engine system further includes an opening degree sensor, The opening degree sensor outputs an opening degree signal indicating the opening degree of the throttle valve. The second pressure is greater than the first pressure. When the intake passage pressure is greater than the first pressure and less than the second pressure, and the opening degree of the throttle valve is greater than a predetermined opening degree, the control device does not change the opening degree of the throttle valve and does not increase the opening degree of the explosion valve. When the intake passage pressure is greater than the first pressure and less than the second pressure, and the opening degree of the throttle valve is less than a predetermined opening degree, the control device does not change the opening degree of the throttle valve and increases the opening degree of the explosion valve. The internal combustion engine system according to the third aspect.

[0010] The fifth aspect is The control device calculates the intake passage pressure based on the differential value of the pressure signal. The internal combustion engine system according to the second or third aspect.

Advantages of the Invention

[0011] According to the present invention, it is possible to reduce the amount of increase in the pressure of the intake passage when backfire occurs.

Brief Description of the Drawings

[0012] [Figure 1] FIG. 1 is a block diagram of the vehicle 1. [Figure 2] FIG. 2 is a configuration diagram of the internal combustion engine system 2. [Figure 3] FIG. 3 is a flowchart executed by the control device 100. [Figure 4] FIG. 4 is a graph showing the relationship between the intake passage pressure P0 and the time t. [Figure 5] FIG. 5 is a flowchart executed by the control device 100.

Modes for Carrying Out the Invention

[0013] (Embodiment) [Structure of Vehicle 1] The structure of a vehicle 1 equipped with an internal combustion engine system 2 according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of the vehicle 1. FIG. 2 is a configuration diagram of the internal combustion engine system 2.

[0014] The vehicle 1 is, for example, a four-wheel automobile. As shown in FIG. 1, the vehicle 1 includes an internal combustion engine system 2, an electric motor 3, a left front wheel 5FL, a right front wheel 5FR, a left rear wheel 5BL, and a right rear wheel 5BR.

[0015] The electric motor 3 generates power by receiving power supply. The electric motor 3 rotates the left front wheel 5FL and the right front wheel 5FR. The internal combustion engine system 2 generates power by burning fuel. The fuel is hydrogen. The internal combustion engine system 2 rotates the left front wheel 5FL and the right front wheel 5FR. Thus, the vehicle 1 is a hybrid vehicle.

[0016] As shown in FIG. 2, the internal combustion engine system 2 includes an internal combustion engine 10, an intake passage R11, an exhaust passage R12, an explosion relief passage R13, a throttle valve 32, an opening sensor 33, an air cleaner 34, an explosion relief valve 36, a pressure sensor 40, a torque sensor 42, and a control device 100.

[0017] The internal combustion engine 10 is a four-cycle engine that uses hydrogen as fuel. In FIG. 2, although one cylinder is shown, the internal combustion engine 10 includes three cylinders. However, since the structures of the three cylinders are the same, the description will focus on one cylinder. 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, a spark plug 24, a ignition coil 26, and an injector 29.

[0018] The engine body 12 includes a cylinder block 12a, a cylinder head 12b, and a crankcase 12c. A cylinder Sy is provided in the cylinder block 12a. The cylinder Sy has a cylindrical shape having a central axis extending along the vertical axis.

[0019] The cylinder head 12b is located on top of 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 on top of the cylinder Sy. The combustion chamber Sp is connected to the cylinder Sy.

[0020] The cylinder head 12b is provided with an intake port PI and an exhaust port PO. The intake port PI is connected to the combustion chamber Sp. The intake path R11 is a pipe through which air passes. The intake path R11 is connected to the intake port PI. In other words, the intake path R11 is connected to the internal combustion engine 10.

[0021] The air cleaner 34 is located in the intake path R11. The air cleaner 34 removes foreign matter from the intake air. The throttle valve 32 is located in the intake path R11. The throttle valve 32 is located downstream of the air cleaner 34. The throttle valve 32 opens and closes the intake path R11 under the control of the control device 100 (described later). As a result, the throttle valve 32 adjusts the amount of air (intake volume) supplied to the internal combustion engine 10.

[0022] The injector 29 is supported by the cylinder head 12b. The injector 29 injects fuel into the combustion chamber Sp of the internal combustion engine 10. In other words, the internal combustion engine 10 employs a direct injection system. This forms a fuel-air mixture in the combustion chamber Sp.

[0023] The exhaust port PO is connected to the combustion chamber Sp. The exhaust path R12 is the piping through which the exhaust gas passes. The exhaust path R12 is connected to the exhaust port PO. In other words, the exhaust path R12 is connected to the internal combustion engine 10.

[0024] The crankcase 12c is located below the cylinder block 12a. The crankcase 12c is fixed to the cylinder block 12a. The engine body 12 described above is made of cast iron.

[0025] The crankshaft 14 is supported by the cylinder block 12a and the crankcase 12c. The crankshaft 14 can rotate about a rotation axis perpendicular to the vertical axis.

[0026] The piston 18 is located within the cylinder Sy. The piston 18 has a cylindrical shape. The piston 18 can move upward and downward.

[0027] 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 mentioned above is the space enclosed by the piston 18 and the cylinder head 12b when the piston 18 is at top dead center (TDC).

[0028] The intake valve 20 is supported by the cylinder head 12b. The intake valve 20 opens and closes the intake port PI. When the intake valve 20 opens the intake port PI, air flows from the intake path R11 through the intake port PI into the combustion chamber Sp.

[0029] The exhaust valve 22 is supported by the cylinder head 12b. The exhaust valve 22 opens and closes the exhaust port PO. When the exhaust valve 22 is open, exhaust gas flows from Sp through the exhaust port PO to the exhaust path R12. The intake valve 20 and exhaust valve 22 described above are driven by a valve train mechanism (not shown).

[0030] 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 ground electrode are exposed to the combustion chamber Sp.

[0031] The ignition coil 26 is electrically connected to the spark plug 24. Based on the ignition signal from the control device 100, the ignition coil 26 applies a high voltage between the center electrode and the ground electrode of the spark plug 24. 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.

[0032] The detonation path R13 is connected to the intake path R11 between the internal combustion engine 10 and the throttle valve 32. More specifically, the detonation path R13 has a first end t1 and a second end t2. The first end t1 is connected to the intake path R11 between the internal combustion engine 10 and the throttle valve 32. The second end t2 is open.

[0033] The detonation valve 36 is located in the detonation path R13. The detonation valve 36 opens and closes the detonation path R13 under the control of the control device 100 (described later). In this way, the detonation valve 36 adjusts the amount of air flowing out from the intake path R11. The detonation valve 36 is an electromagnetic valve. The detonation valve 36 includes, for example, a canopy valve that can seal the detonation path R13. This prevents air from the intake path R11 from flowing into the detonation path R13 when the detonation valve 36 is in a fully closed state.

[0034] The pressure sensor 40 outputs a pressure signal Sig1 indicating the intake path pressure P0 of the intake path R11 between the internal combustion engine 10 and the throttle valve 32. When the intake path pressure P0 increases, the voltage of the pressure signal Sig1 increases. When the intake path pressure P0 decreases, the voltage of the pressure signal Sig1 decreases. In this embodiment, the pressure sensor 40 is a general intake pressure sensor used in vehicles.

[0035] The opening degree sensor 33 outputs an opening degree signal Sig2 indicating the opening degree φ0 of the throttle valve 32. When the opening degree φ0 increases, the voltage of the opening degree signal Sig2 increases. When the opening degree φ0 decreases, the voltage of the opening degree signal Sig2 decreases. The opening degree φ0 is the value obtained by dividing the current opening amount of the throttle valve 32 by the opening amount of the throttle valve 32 when it is fully open and multiplying by 100. The opening amount is the angle of the throttle valve 32. When the throttle valve 32 is in the fully open state, the angle of the throttle valve 32 when it is in the fully closed state is 0 degrees when the throttle valve 32 is fully open.

[0036] The torque sensor 42 outputs a torque signal Sig3 that indicates the magnitude of the torque T1 output by the internal combustion engine 10. When the torque T1 increases, the voltage of the torque signal Sig3 increases. When the torque T1 decreases, the voltage of the torque signal Sig3 decreases. The torque sensor 42 is mounted, for example, on the crankshaft 14.

[0037] The control device 100 controls the operation of the internal combustion engine 10 and the electric motor 3. In this embodiment, the control device 100 controls the amount of fuel injected by the injector 29 and the timing of the discharge of the spark plug 24. Furthermore, the control device 100 controls the operation of the throttle valve 32 and the detonation valve 36. The control device 100 is, for example, an ECU (Engine Control Unit) and includes a circuit board and electronic components.

[0038] [Operation of Internal Combustion Engine System 2] Next, the operation of the internal combustion engine system 2 will be explained with reference to the drawings. Figures 3 and 5 are flowcharts executed by the control device 100. Figure 4 is a graph showing the relationship between the intake path pressure P0 and time t. The vertical axis represents the intake path pressure P0, and the horizontal axis represents time t.

[0039] First, let me explain the prerequisites. At the start, the opening degree φ10 of the detonation valve 36 is 0%. In other words, the state of the detonation valve 36 is fully closed.

[0040] Furthermore, the second pressure P2 is greater than the first pressure P1. The third pressure P3 is greater than the second pressure P2. If the intake path pressure P0 is less than the first pressure P1, no backfire occurs. If the intake path pressure P0 is greater than or equal to the first pressure P1, backfire occurs. If the intake path pressure P0 is greater than or equal to the first pressure P1 and less than the second pressure P2, backfire occurs to the extent that the air cleaner 34 is not damaged. If the intake path pressure P0 is greater than or equal to the second pressure P2 and less than the third pressure P3, backfire occurs to the extent that the air cleaner 34 is damaged but the throttle valve 32 is not damaged. If the intake path pressure P0 is greater than or equal to the third pressure P3, backfire occurs to the extent that the throttle valve 32 is damaged.

[0041] First, the control device 100 acquires a pressure signal Sig1 from the pressure sensor 40 (step S1). Then, the control device 100 calculates the derivative value p0 by differentiating the intake path pressure P0 indicated by the pressure signal Sig1 (step S2). Here, we will explain why the control device 100 calculates the derivative value p0.

[0042] As described above, the pressure sensor 40 is a general intake pressure sensor used in vehicle 1. As shown in the graph in Figure 4, the upper limit P10 of the pressure that the pressure sensor 40 can measure is relatively small. On the other hand, the intake path pressure P0 when backfire occurs is relatively large. Therefore, the pressure sensor 40 cannot measure the intake path pressure P0 when backfire occurs. The control device 100 calculates the intake path pressure P0 based on the differential value p0 (slope) of the pressure signal Sig1.

[0043] Next, the control device 100 determines whether the intake path pressure P0 is greater than or equal to the first pressure P1 (step S3). More specifically, a memory device (not shown) stores the first derivative value p1 corresponding to the first pressure P1. The control device 100 determines whether the derivative value p0 calculated in step S2 is greater than or equal to the first derivative value p1. If the derivative value p0 is less than the first derivative value p1, the control device 100 determines that the intake path pressure P0 is less than the first pressure P1. After this, the process proceeds to step S4. If the derivative value p0 is greater than or equal to the first derivative value p1, the control device 100 determines that the intake path pressure P0 is greater than or equal to the first pressure P1. After this, the process proceeds to step S5.

[0044] If the intake path pressure P0 is less than the first pressure, the control device 100 determines that no backfire has occurred. Therefore, the control device 100 maintains the state of the detonation valve 36 in a fully closed state and maintains the opening degree φ0 of the throttle valve 32 at the current opening degree (step S4). In other words, the control device 100 performs normal control on the throttle valve 32. Normal control means that the control device 100 controls the opening degree φ0 of the throttle valve 32 based on the amount the accelerator pedal is depressed, the rotational speed of the internal combustion engine 10, the opening degree φ0, the intake path pressure P0 (intake pressure), the vehicle speed and the oxygen concentration in the exhaust gas, as well as a preset map (not shown).

[0045] If the intake path pressure P0 is greater than or equal to the first pressure P1, the control device 100 determines that a backfire has occurred. In this way, the control device 100 determines whether a backfire has occurred by determining whether the intake path pressure P0 has become greater than the first pressure P1 based on the pressure signal Sig1. Then, the control device 100 determines whether the intake path pressure P0 is greater than or equal to the second pressure P2 (step S5). More specifically, a memory device (not shown) stores the second derivative value p2 corresponding to the second pressure P2. The second pressure P2 is greater than the first pressure P1. Therefore, the second derivative value p2 is greater than the first derivative value p1. The control device 100 determines whether the derivative value p0 calculated in step S2 is greater than or equal to the second derivative value p2. If the derivative value p0 is less than the second derivative value p2, the control device 100 determines that the intake path pressure P0 is less than the second pressure P2. After this, the process proceeds to step S6. If the differential value p0 is greater than or equal to the second differential value p2, the control device 100 determines that the intake path pressure P0 is greater than or equal to the second pressure P2. After this, the process proceeds to step S9.

[0046] If the intake path pressure P0 is less than the second pressure P2, the control device 100 determines that backfire is occurring to an extent that does not damage the air cleaner 34. The control device 100 determines whether the opening degree φ0 indicated by the opening degree signal Sig2 is less than or equal to a predetermined opening degree φ1 (step S6). If the opening degree φ0 is greater than the predetermined opening degree φ1, the process proceeds to step S7. If the opening degree φ0 is less than or equal to the predetermined opening degree φ1, the process proceeds to step S8.

[0047] If the opening degree φ0 is greater than the predetermined opening degree φ1, the control device 100 maintains the state of the detonation valve 36 in a fully closed state and maintains the opening degree φ0 of the throttle valve 32 (step S7). If the intake path pressure P0 is greater than the first pressure P1 and less than the second pressure P2, and the opening degree φ0 of the throttle valve 32 is greater than the predetermined opening degree φ1, the control device 100 does not change the opening degree φ0 of the throttle valve 32 and does not increase the opening degree φ10 of the detonation valve 36. In this way, if the opening degree φ0 of the throttle valve 32 is large, when the intake path pressure P0 rises, air in the intake path R11 will flow out from the throttle valve 32. Therefore, even if the control device 100 maintains the state of the detonation valve 36 in a closed state, the intake path pressure P0 is less likely to rise. Also, the strength of the backfire is such that the air cleaner 34 is not damaged. Therefore, the air cleaner 34 is less likely to be damaged. After this, the process proceeds to step S12.

[0048] If the opening degree φ0 is less than or equal to a predetermined opening degree φ1, the control device 100 opens the detonation valve 36 to its fully open state and maintains the opening degree φ0 of the throttle valve 32 (step S8). If the intake path pressure P0 is greater than the first pressure P1 and less than the second pressure P2, and the opening degree φ0 of the throttle valve 32 is less than the predetermined opening degree φ1, the control device 100 does not change the opening degree φ0 of the throttle valve 32 and increases the opening degree φ10 of the detonation valve 36. In this way, if the opening degree φ0 of the throttle valve 32 is small, the air cleaner 34 is less likely to be damaged by the rise in intake path pressure P0 caused by backfire. Therefore, the control device 100 does not change the opening degree φ0 of the throttle valve 32. After this, the process proceeds to step S12.

[0049] If the intake path pressure P0 is greater than or equal to the second pressure P2, the control device 100 determines whether the intake path pressure P0 is greater than or equal to the third pressure P3 (step S9). More specifically, a memory device (not shown) stores the third derivative value p3 corresponding to the third pressure P3. The third pressure P3 is greater than the second pressure P2. Therefore, the third derivative value p3 is greater than the second derivative value p2. The control device 100 determines whether the derivative value p0 calculated in step S2 is greater than or equal to the third derivative value p3. If the derivative value p0 is less than the third derivative value p3, the control device 100 determines that the intake path pressure P0 is less than the third pressure P3. After this, the process proceeds to step S10. If the derivative value p0 is greater than or equal to the third derivative value p3, the control device 100 determines that the intake path pressure P0 is greater than or equal to the third pressure P3. After this, the process proceeds to step S11.

[0050] If the intake path pressure P0 is less than the third pressure P3, the control device 100 determines that a backfire has occurred that is not severe enough to damage the air cleaner 34 but not the throttle valve 32. The control device 100 opens the detonation valve 36 completely and closes the throttle valve 32 completely (step S10). If the intake path pressure P0 is greater than the second pressure P2 and less than the third pressure P3, the control device 100 decreases the opening degree φ0 of the throttle valve 32 and increases the opening degree φ10 of the detonation valve 36. In this way, when a backfire occurs, the opening degree φ10 of the detonation valve 36 increases and the control device 100 changes the opening degree φ0 of the throttle valve 32. This makes it less likely for the air cleaner 34 to be damaged by the rise in intake path pressure P0 caused by the backfire. After this, the process proceeds to step S12.

[0051] If the intake path pressure P0 is greater than or equal to the third pressure P3, the control device 100 determines that a backfire has occurred that is severe enough to damage the throttle valve 32. The control device 100 opens both the detonation valve 36 and the throttle valve 32 to their full positions (step S11). If the intake path pressure P0 is greater than the third pressure P3, the control device 100 increases the opening degree φ0 of the throttle valve 32 and increases the opening degree φ10 of the detonation valve 36. In this way, when a backfire occurs, the opening degree φ10 of the detonation valve 36 increases, and the control device 100 changes the opening degree φ0 of the throttle valve 32. This makes it less likely for the throttle valve 32 to be damaged by the rise in intake path pressure P0 caused by the backfire. After this, the process proceeds to step S12.

[0052] In step S12, the control device 100 determines whether or not to terminate this process (step S12). In step S12, the control device 100 determines whether or not the driver has stopped the internal combustion engine 10. If the driver has stopped the internal combustion engine 10, the control device 100 determines to terminate this process. If the driver has not stopped the internal combustion engine 10, the control device 100 determines not to terminate this process. In this case, the process returns to step S1.

[0053] Incidentally, while the control device 100 is executing the flowchart shown in Figure 4, it is also executing the flowchart shown in Figure 5. More specifically, when backfire occurs, the control device 100 may open the detonation valve 36 to a fully open state. In this case, the fuel decreases due to the backfire, and the A / F ratio increases. As a result, the torque T1 output by the internal combustion engine 10 decreases. Therefore, the control device 100 compensates for the decrease in torque T1 output by the internal combustion engine 10 with torque T2 from the electric motor 3 by executing the flowchart shown in Figure 5.

[0054] First, the control device 100 acquires a torque signal Sig3 from the torque sensor 42 (step S21). The control device 100 determines whether the amount of fluctuation of the torque T1 indicated by the torque signal Sig3 is greater than or equal to a predetermined value (step S22). The predetermined value is a value that the driver would find uncomfortable. If the amount of fluctuation of the torque T1 is greater than or equal to the predetermined value, the process proceeds to step S23. If the amount of fluctuation of the torque T1 is not greater than or equal to the predetermined value, the process returns to step S21.

[0055] If the amount of fluctuation in torque T1 is greater than or equal to a predetermined value, the control device 100 drives the electric motor 3 (step S23). More specifically, a memory device (not shown) stores a table showing the relationship between the amount of fluctuation in torque T1 and the torque T2 output by the electric motor 3. The control device 100 causes the electric motor 3 to output a torque T2 corresponding to the torque T1 indicated by the torque signal Sig3 acquired in step S21. After this, the process proceeds to step S24.

[0056] Next, the control device 100 determines whether or not to terminate this process (step S24). In step S24, the control device 100 determines whether or not the driver has stopped the internal combustion engine 10. If the driver has stopped the internal combustion engine 10, the control device 100 determines to terminate this process. If the driver has not stopped the internal combustion engine 10, the control device 100 determines not to terminate this process. In this case, the process returns to step S21.

[0057] [effect] According to the internal combustion engine system 2, the increase in intake path pressure P0 when backfire occurs can be reduced. More specifically, when backfire occurs, the opening degree φ10 of the detonation valve 36 increases, and the control device 100 changes the opening degree φ0 of the throttle valve 32. As a result, the air in the intake path R11 flows out of the intake path R11 through the detonation valve 36. Consequently, according to the internal combustion engine system 2, the increase in intake path pressure P0 when backfire occurs can be reduced.

[0058] According to the internal combustion engine system 2, the probability of damage to the throttle valve 32 and air cleaner 34 due to backfire can be reduced. More specifically, when backfire occurs, the opening degree φ10 of the detonation valve 36 increases, and the control device 100 changes the opening degree φ0 of the throttle valve 32. Therefore, the opening degree φ0 of the throttle valve 32 can be changed according to the intensity of the backfire. As a result, the control device 100 can control the throttle valve 32 to an opening degree φ0 suitable for protecting the throttle valve 32, and also to an opening degree φ0 suitable for protecting the detonation valve 36.

[0059] According to the internal combustion engine system 2, the probability of damage to the throttle valve 32 and air cleaner 34 due to backfire can be reduced. More specifically, when the intake path pressure P0 is greater than the second pressure P2 and less than the third pressure P3, the control device 100 decreases the opening degree φ0 of the throttle valve 32 and increases the opening degree φ10 of the detonation valve 36. This makes it less likely for the air cleaner 34 to be damaged by the rise in intake path pressure P0 caused by backfire. Also, when the intake path pressure P0 is greater than the third pressure P3, the control device 100 increases the opening degree φ0 of the throttle valve 32 and increases the opening degree φ10 of the detonation valve 36. This makes it less likely for the throttle valve 32 to be damaged by the rise in intake path pressure P0 caused by backfire.

[0060] According to the internal combustion engine system 2, the probability of damage to the throttle valve 32 and air cleaner 34 due to backfire can be reduced. When the intake path pressure P0 is greater than the first pressure P1 and less than the second pressure P2, and the opening degree φ0 of the throttle valve 32 is greater than a predetermined opening degree φ1, the control device 100 does not change the opening degree φ0 of the throttle valve 32 and does not increase the opening degree φ10 of the detonation valve 36. In this way, when the opening degree φ0 of the throttle valve 32 is large, if the intake path pressure P0 rises, air in the intake path R11 will flow out from the throttle valve 32. Therefore, the control device 100 maintains the state of the detonation valve 36 in the closed state. This makes it difficult for the intake path pressure P0 to rise. However, the intensity of the backfire is not strong enough to damage the air cleaner 34. Therefore, the air cleaner 34 is less likely to be damaged. When the intake path pressure P0 is greater than the first pressure P1 and less than the second pressure P2, and the opening degree φ0 of the throttle valve 32 is less than a predetermined opening degree φ1, the control device 100 does not change the opening degree φ0 of the throttle valve 32, but increases the opening degree φ10 of the explosion valve 36. The opening degree φ0 of the throttle valve 32 is small. Therefore, the air cleaner 34 is less likely to be damaged by the rise in intake path pressure P0 caused by backfire.

[0061] According to the internal combustion engine system 2, a general intake pressure sensor used in vehicle 1 can be used as the pressure sensor 40. More specifically, as shown in Figure 3, the upper limit P10 of the pressure that a general intake pressure sensor used in vehicle 1 can measure is relatively small. On the other hand, the intake path pressure P0 when backfire occurs is relatively large. Therefore, a general intake pressure sensor used in vehicle cannot measure the intake path pressure P0 when backfire occurs. Thus, the control device 100 calculates the intake path pressure P0 based on the first derivative value p1 of the pressure signal Sig1. As a result, according to the internal combustion engine system 2, a general intake pressure sensor used in vehicle can be used as the pressure sensor 40.

[0062] In the internal combustion engine system 2, the fuel is hydrogen. Hydrogen is more easily ignited than hydrocarbon fuels. Therefore, backfire is more likely to occur. Consequently, when the internal combustion engine system 2 is applied to the internal combustion engine 10, which uses hydrogen as fuel, the probability of damage to the throttle valve 32 and air cleaner 34 due to backfire can be effectively reduced.

[0063] (Other embodiments) The internal combustion engine system according to the present invention is not limited to internal combustion engine system 2, but can be modified within the scope of its gist.

[0064] In addition, the pressure sensor 40 may be a pressure sensor capable of measuring the intake air path pressure P0 at the time of backfire, instead of a general intake pressure sensor used in the vehicle 1. In this case, the control device 100 does not need to calculate the first derivative value p1.

[0065] Furthermore, in step S23, the control device 100 may advance the ignition timing of the spark plug 24 or increase the amount of fuel injected by the injector 29. However, if the throttle valve 32 is fully closed in step S10, the internal combustion engine 10 will stall. In such a case, it is not possible to advance the ignition timing or increase the amount of fuel injected. Therefore, the control device 100 drives the electric motor 3.

[0066] Furthermore, the fuel may not be hydrogen. For example, the fuel may be a hydrocarbon-based fuel such as gasoline or alcohol.

[0067] The first pressure P1 to the third pressure P3 may be a constant value determined by experiments, etc., or it may be a value that fluctuates according to the driving conditions of vehicle 1.

[0068] The detonation valve 36 is a solenoid valve, but it may also be a spring-type valve.

[0069] The explosion release valve 36 may also be an EGR (Exhaust Gas Recirculation) valve.

[0070] In step S3, the control device 100 may determine whether the intake path pressure P0 is greater than the first pressure P1.

[0071] In step S5, the control device 100 may determine whether the intake path pressure P0 is greater than the second pressure P2.

[0072] In step S9, the control device 100 may determine whether the intake path pressure P0 is greater than the third pressure P3.

[0073] In step S6, the control device 100 may determine whether the opening degree φ0 indicated by the opening degree signal Sig2 is smaller than a predetermined opening degree φ1. [Explanation of Symbols]

[0074] 1: Vehicle 2: Internal combustion engine system 3: Electric motor 10: Internal combustion engine 32: Throttle valve 33: Opening degree sensor 34: Air cleaner 36: Detonation valve 40: Pressure sensor 42: Torque sensor 100: Control device P0: Intake path pressure P1: First pressure P10: Upper limit P2: Second pressure P3: Third pressure PI: Intake port PO: Exhaust port R11: Intake path R12: Exhaust path R13: Detonation path Sig1: Pressure signal Sig2: Opening signal Sig3: Torque signal φ0, φ10: Opening degree φ1: Determined opening degree

Claims

1. The internal combustion engine system comprises an internal combustion engine, an intake path, a detonation path, a throttle valve, a detonation valve, and a control device. The intake path is connected to the internal combustion engine, The throttle valve is provided in the intake path, The explosion path is connected to the intake path between the internal combustion engine and the throttle valve. The aforementioned detonation valve is provided in the detonation path, When a backfire occurs, the opening of the detonation valve increases, and the control device changes the opening of the throttle valve. Internal combustion engine system.

2. The aforementioned internal combustion engine system further includes a pressure sensor. The pressure sensor outputs a pressure signal indicating the intake path pressure in the intake path between the internal combustion engine and the throttle valve. The control device determines whether or not backfire has occurred by determining, based on the pressure signal, whether or not the intake path pressure has become greater than the first pressure. The internal combustion engine system according to claim 1.

3. The second pressure is greater than the first pressure. The third pressure is greater than the previous second pressure. If the intake path pressure is greater than the second pressure and less than the third pressure, the control device reduces the opening of the throttle valve and increases the opening of the detonation valve. If the intake path pressure is greater than the third pressure, the control device increases the opening of the throttle valve and also increases the opening of the detonation valve. The internal combustion engine system according to claim 2.

4. The aforementioned internal combustion engine system further includes an opening degree sensor, The opening degree sensor outputs an opening degree signal indicating the opening degree of the throttle valve. The second pressure is greater than the first pressure. If the intake path pressure is greater than the first pressure and less than the second pressure, and the throttle valve opening is greater than a predetermined opening, the control device does not change the throttle valve opening and does not increase the explosion valve opening. If the intake path pressure is greater than the first pressure and less than the second pressure, and the throttle valve opening is less than a predetermined opening, the control device does not change the throttle valve opening and increases the explosion valve opening. The internal combustion engine system according to claim 3.

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