Internal combustion engine controller, and control method for internal combustion engine

Abstract

To provide a control part capable of appropriately controlling an internal combustion engine even when noise is mixed into a state signal.SOLUTION: A controller 12 for an internal combustion engine 10 which has a throttle drive part 24 driving a throttle valve 22 includes: a control part 72 controlling the internal combustion engine; and a driving circuit 70 driving the throttle drive part. The driving circuit transmits to the control part a signal group connecting a plurality of state signals indicating the state of driving circuit every prescribed cycle. The control unit controls the internal combustion engine on the basis of state signals occupying a majority of the plurality of state signals by making a majority decision of the plurality of state signals included in a received signal group.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] The following Patent Document 1 discloses an in-cylinder pressure detection device that detects the in-cylinder pressure, which is the pressure in the cylinder of an internal combustion engine. The in-cylinder pressure detection device corrects the detected in-cylinder pressure according to the intake pressure acquired during the intake stroke of the cylinder to be detected. This prevents the accuracy of the corrected in-cylinder pressure from being reduced by noise caused by ignition by the spark plug. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-197083 A Summary of the Invention [Problem to be solved by the invention]

[0004] Recently, there has been a demand for a better control device for an internal combustion engine and a control method for an internal combustion engine. [Means for solving the problem]

[0005] A first aspect of the present invention provides a control device for an internal combustion engine, comprising a control unit for controlling an internal combustion engine, and a drive circuit for driving a throttle drive unit which drives a throttle valve, wherein the drive circuit transmits a signal group including a plurality of status signals indicating a state of the drive circuit to the control unit at predetermined intervals, and the control unit controls the internal combustion engine based on the status signal which accounts for the majority of the plurality of status signals by making a majority decision on the plurality of status signals included in the received signal group.

[0006] A second aspect of the present invention provides a method for controlling an internal combustion engine, comprising: a transmitting step in which a drive circuit that drives a throttle drive unit that drives a throttle valve transmits a signal group consisting of a plurality of status signals indicating a state of the drive circuit to a control unit that controls the internal combustion engine at a predetermined period; a receiving step in which the control unit receives the signal group; and a control step in which the control unit controls the internal combustion engine based on the state signal that occupies the majority of the plurality of state signals by making a majority decision on the plurality of state signals included in the received signal group. Effect of the Invention

[0007] According to the present invention, it is possible to provide a better control device for an internal combustion engine and a control method for an internal combustion engine. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of an internal combustion engine and a control device that controls the internal combustion engine. [Diagram 2] FIG. 2 is a diagram illustrating the status signal. [Diagram 3] FIG. 3 is a time chart of the processes performed in the control unit and the drive circuit. [Figure 4] FIG. 4 is a flowchart showing the throttle control process performed in the control unit. [Diagram 5] FIG. 5 is a flowchart showing the majority decision process performed in the control unit. [Figure 6] FIG. 6 is a flow chart showing signal group transmission performed in the drive circuit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The internal combustion engine includes a throttle valve and a throttle drive unit that drives the throttle valve. The control device for the internal combustion engine includes a control unit that controls the internal combustion engine and a drive circuit that drives the throttle drive unit. The drive circuit transmits a status signal indicating the status of the drive circuit to the control unit at predetermined intervals. The control unit controls the internal combustion engine based on the received status signal.

[0010] When a discharge occurs in the spark plug of the internal combustion engine to ignite the air-fuel mixture, noise may be mixed into the status signal, causing a bit error. When a bit error occurs, the content of the status signal generated in the drive circuit differs from the content of the status signal received by the control unit. When the cycle at which the drive circuit transmits the status signal matches the ignition interval of the spark plug of the internal combustion engine, noise may be mixed into the status signal every time the drive circuit transmits a status signal.

[0011] For example, if the internal combustion engine is a four-cylinder engine, the ignition interval of the spark plug is 2 ms when the rotation speed is 15,000 rpm. If the period in which the drive circuit transmits the status signal is 2 ms, the ignition interval of the spark plug of the internal combustion engine will match when the rotation speed is 15,000 rpm. If the state in which the period in which the drive circuit transmits the status signal matches the ignition interval of the spark plug of the internal combustion engine continues for a long period of time, there is a risk that the control unit will not be able to properly control the internal combustion engine.

[0012] The control device for an internal combustion engine according to the present disclosure allows the control unit to appropriately control the internal combustion engine even when noise is mixed into the status signal. Also, the control method for an internal combustion engine according to the present disclosure allows the control unit to appropriately control the internal combustion engine even when noise is mixed into the status signal.

[0013] [Configuration of the internal combustion engine and control device] 1 is a schematic diagram of an internal combustion engine 10 and a control device 12 that controls the internal combustion engine 10. The internal combustion engine 10 is an engine mounted on a saddle-type vehicle such as a motorcycle. The internal combustion engine 10 may be mounted on a moving body other than a saddle-type vehicle. The internal combustion engine 10 is not limited to being mounted on a moving body, and may be mounted on a device installed on the ground such as a residential generator. The fuel used in the internal combustion engine 10 is, for example, gasoline. The fuel used in the internal combustion engine 10 may also be diesel, biomass ethanol, liquefied petroleum gas, etc.

[0014] The internal combustion engine 10 is equipped with an electronically controlled throttle 14, a fuel injector 16, an ignition device 18, and an exhaust purification device 20.

[0015] The electronically controlled throttle 14 has a throttle valve 22, a throttle drive unit 24, and a throttle position sensor 26. The throttle valve 22 is a butterfly throttle that adjusts the amount of air supplied to an intake port 30 provided upstream of an intake valve 28. The throttle drive unit 24 is a motor. The throttle drive unit 24 drives the throttle valve 22 to open and close the throttle valve 22. The throttle position sensor 26 detects the opening degree of the throttle valve 22.

[0016] The fuel injection device 16 has a fuel injection valve 32. The fuel injection valve 32 is provided in the intake port 30. The fuel injection valve 32 injects fuel into the intake port 30. This generates a mixture of fuel and air. If the internal combustion engine 10 is a direct fuel injection engine, the fuel injection valve 32 may be provided in the cylinder head 40 and directly inject fuel into the combustion chamber 34.

[0017] The ignition device 18 has an ignition plug 36 and an ignition coil 38. The ignition plug 36 and the ignition coil 38 are provided in a cylinder head 40. The ignition plug 36 discharges electricity in the combustion chamber 34 to ignite the air-fuel mixture. The ignition coil 38 boosts the voltage of a battery (not shown). The ignition plug 36 uses the boosted electricity to discharge electricity.

[0018] The exhaust purification device 20 has a three-way catalyst 42. The three-way catalyst 42 is provided in an exhaust port 46 downstream of an exhaust valve 44. The three-way catalyst 42 removes harmful substances contained in the gas discharged from the combustion chamber 34 by means of a catalyst.

[0019] The internal combustion engine 10 is equipped with various sensors for detecting the operating state of the internal combustion engine 10. The internal combustion engine 10 is equipped with an intake air temperature sensor 48, an intake pressure sensor 50, a crank angle sensor 52, a coolant temperature sensor 54, and an oxygen concentration sensor 56.

[0020] The intake air temperature sensor 48 is provided in the intake duct 58 upstream of the throttle valve 22. The intake air temperature sensor 48 detects the temperature in the intake duct 58. The intake air pressure sensor 50 is provided in the intake port 30. The intake air pressure sensor 50 detects the pressure in the intake port 30. The crank angle sensor 52 detects the rotation angle of the crankshaft 60. The crank angle sensor 52 detects the rotation angle of the crankshaft 60 based on a pulse signal generated by a protrusion of a signal rotor 62 that rotates together with the crankshaft 60. The cooling water temperature sensor 54 is provided in the cylinder 64. The cooling water temperature sensor 54 detects the temperature of the cooling water in the cooling water jacket. The oxygen concentration sensor 56 is provided in the exhaust port 46 upstream of the three-way catalyst 42. The oxygen concentration sensor 56 detects the concentration of oxygen contained in the gas discharged from the combustion chamber 34.

[0021] The control device 12 includes a calculation unit 66, a storage unit 68, and a drive circuit 70. The calculation unit 66 is a processor such as a central processing unit (CPU) or a graphics processing unit (GPU). The calculation unit 66 has a control unit 72. The control unit 72 is realized by executing a program stored in the storage unit 68 in the calculation unit 66. At least a part of the control unit 72 may be realized by an integrated circuit such as an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA). At least a part of the control unit 72 may be realized by an electronic circuit including discrete devices.

[0022] The storage unit 68 is a computer-readable storage medium. The storage unit 68 is configured by a volatile memory (not shown) and a non-volatile memory (not shown). The volatile memory is, for example, a random access memory (RAM). The non-volatile memory is, for example, a read only memory (ROM), a flash memory, etc. Data, etc. are stored in, for example, the volatile memory. Programs, tables, maps, etc. are stored in, for example, the non-volatile memory. At least a part of the storage unit 68 may be provided in the above-mentioned processor, integrated circuit, etc.

[0023] The drive circuit 70 is a motor driver that drives the throttle drive unit 24 based on a command from the control unit 72. The drive circuit 70 transmits a status signal indicating the status of the drive circuit 70 to the control unit 72. The drive circuit 70 and the control unit 72 are connected by a communication bus 74.

[0024] The communication bus 74 is a Serial Peripheral Interface (SPI). The SPI is a clock-synchronized serial interface. The communication bus 74 provided between the drive circuit 70 and the control unit 72 has four signal lines. The four signal lines are CLK (Clock), MISO (Master In Slave Out), MOSI (Master Out Slave In), and CS (Chip Select). CLK is a signal line that transmits a clock signal from the control unit 72 to the drive circuit 70. MISO is a signal line that transmits information from the drive circuit 70 to the control unit 72. MOSI is a signal line that transmits information from the control unit 72 to the drive circuit 70. CS is a signal line that transmits a signal that selects an integrated circuit (IC) with which the control unit 72 communicates. Although only the drive circuit 70 is shown in FIG. 1 as a communication partner of the control unit 72, in reality, the control unit 72 communicates with a plurality of ICs including the drive circuit 70.

[0025] [About status signals] FIG. 2 is a diagram for explaining the status signal. The status signal is an 8-bit signal. The drive circuit 70 has a self-diagnosis function. For example, when the drive circuit 70 detects that an overcurrent has occurred in the drive circuit 70, the drive circuit 70 places information indicating that an overcurrent has occurred in the drive circuit 70 in the status signal. For example, the second bit of the status signal being "1" indicates that an overcurrent has occurred in the drive circuit 70. For example, when the drive circuit 70 detects that an overheat state of the drive circuit 70 has occurred, the drive circuit 70 places information indicating that an overheat state of the drive circuit 70 has been detected in the status signal. For example, the first bit of the status signal being "1" indicates that an overheat state of the drive circuit 70 has been detected.

[0026] 3 is a time chart of the processing performed in the control unit 72 and the drive circuit 70. The control unit 72 performs chip select to switch the CS signal of the communication bus 74 connecting the control unit 72 and the drive circuit 70 from "1" to "0". This selects the drive circuit 70 as a communication partner of the control unit 72. When the drive circuit 70 is selected as a communication partner of the control unit 72, the drive circuit 70 transmits a status signal to the control unit 72 using the MISO of the communication bus 74.

[0027] The control unit 72 selects the drive circuit 70 three times in succession. As a result, the drive circuit 70 transmits a status signal to the control unit 72 three times in succession. Here, the three transmitted status signals are defined as status signal A, status signal B, and status signal C. A signal group is formed by connecting three status signals together with the status signal A, status signal B, and status signal C. The status signal A, status signal B, and status signal C transmitted from the drive circuit 70 are transmitted consecutively within a short period of time (2 ms), so that the information contained in the status signal A, status signal B, and status signal C is usually the same. The number of status signals contained in the signal group may be three or more. The number of status signals contained in the signal group may be an odd number. If the number of status signals contained in the signal group is an odd number of three or more, the majority decision described below can be reliably performed.

[0028] The control unit 72 selects the drive circuit 70 three times per predetermined period (e.g., 2 ms). That is, the drive circuit 70 transmits a group of signals to the control unit 72 for each predetermined period. In other words, the drive circuit 70 transmits a status signal to the control unit 72 three times for each predetermined period.

[0029] The period during which the drive circuit 70 transmits the signal group matches the ignition interval of the spark plug 36 when the rotation speed of the internal combustion engine 10 is a predetermined rotation speed. For example, if the internal combustion engine 10 is a four-cylinder engine, the ignition interval of the spark plug 36 is 2 ms when the rotation speed is 15,000 rpm. When the period during which the drive circuit 70 transmits the signal group is 2 ms, the ignition interval of the spark plug 36 when the rotation speed of the internal combustion engine 10 is 15,000 rpm matches the period during which the drive circuit 70 transmits the signal group.

[0030] The control unit 72 receives the signal group. The control unit 72 performs a majority decision on three status signals included in the received signal group. The majority decision adopts a status signal that is the majority of the three status signals. In other words, the majority decision adopts one of two or more status signals having the same information among the three status signals. For example, when noise is mixed into the status signal B and the information of the status signal B is different from the information of the status signal A and the information of the status signal C, the control unit 72 adopts one of the status signals A and C, which are the status signals indicating the majority among the three status signals of the signal group, by the majority decision. Since noise occurs in an extremely short time, it is rare for noise to be mixed into two or more status signals among the three status signals. When the signal group includes an odd number of status signals, 5 or more, one status signal among the status signals having the largest number of status signals having the same information among the multiple status signals included in the signal group may be adopted by the majority decision.

[0031] The control unit 72 controls the electronically controlled throttle 14 based on the state signal adopted by majority decision. For example, when the information of the state signal indicates an abnormality such as an overcurrent in the drive circuit 70 or overheating of the drive circuit 70, the control unit 72 controls the electronically controlled throttle 14 to minimize the opening of the throttle valve 22. This allows the internal combustion engine 10 to maintain a low rotation speed even when the throttle drive unit 24 cannot be driven due to an abnormality in the drive circuit 70. That is, the control unit 72 can appropriately control the internal combustion engine 10. When an abnormality in the drive circuit 70 is detected, the drive of the throttle drive unit 24 may be prohibited. When an abnormality in the drive circuit 70 is detected, the operation of the internal combustion engine 10 may be stopped by prohibiting the ignition of the mixture by the ignition plug 36. When an abnormality in the drive circuit 70 is detected, the operation of the internal combustion engine 10 may be stopped by prohibiting the injection of fuel into the intake port 30 by the fuel injection valve 32.

[0032] [Throttle control processing] 4 is a flowchart showing the throttle control process performed in the control unit 72. The control unit 72 repeatedly executes the throttle control process at a predetermined cycle.

[0033] In step S1, the control unit 72 assigns "0" to a counter N. Then, the process proceeds to step S2.

[0034] In step S2, the control unit 72 switches the CS signal of the communication bus 74 connecting the control unit 72 and the drive circuit 70 from "1" to "0." This selects the drive circuit 70 as a communication partner of the control unit 72. Then, the process proceeds to step S3.

[0035] In step S3, the control unit 72 receives the status signal transmitted by the drive circuit 70. After that, the process proceeds to step S4.

[0036] In step S4, the control unit 72 switches the CS signal of the communication bus 74 connecting the control unit 72 and the drive circuit 70 from "0" to "1." This causes the drive circuit 70 to be deselected as a communication partner of the control unit 72. Then, the process proceeds to step S5.

[0037] In step S5, the control unit 72 increments the counter N. After that, the process proceeds to step S6.

[0038] In step S6, the control unit 72 determines whether the counter N is equal to or greater than 3. If it is determined that the counter N is equal to or greater than 3, the control unit 72 proceeds to step S7. If it is determined that the counter N is less than 3, the control unit 72 returns to step S2.

[0039] In step S7, the control unit 72 determines whether or not the control unit 72 has received the signal group. If it is determined that the control unit 72 has received the signal group, the process proceeds to step S8. If it is determined that the control unit 72 has not received the signal group, the throttle control process ends.

[0040] When the control unit 72 receives three status signals after repeating the processes of steps S2 to S4 three times, the control unit 72 determines that the control unit 72 has received a signal group. When the control unit 72 does not receive three status signals after repeating the processes of steps S2 to S4 three times, the control unit 72 determines that the control unit 72 has not received a signal group.

[0041] If it is determined that the control unit 72 has not received the group of signals, the status signals received in the throttle control processing of the current cycle may be discarded, and processing from step S8 onwards may be performed based on the three status signals received in the throttle control processing of the previous cycle.

[0042] In step S8, the control unit 72 performs majority decision processing. Then, the process proceeds to step S9. The majority decision processing will be described in detail later.

[0043] In step S9, the electronically controlled throttle 14 is controlled based on the state signal adopted by the majority decision process, after which the throttle control process ends.

[0044] 5 is a flowchart showing the majority decision process performed in the control unit 72. The majority decision process is executed every time step S4 of the throttle control process is performed. Here, the received signal group includes three status signals, status signal A, status signal B, and status signal C.

[0045] In step S11, the control unit 72 determines whether the information of the status signal A and the information of the status signal B are the same. If it is determined that the information of the status signal A and the information of the status signal B are the same, the process proceeds to step S12. If it is determined that the information of the status signal A and the information of the status signal B are different, the process proceeds to step S13.

[0046] In step S12, the control unit 72 adopts the status signal A from among the three status signals in the signal group, and then ends the majority decision process.

[0047] In step S13, the control unit 72 determines whether the information of the status signal A and the information of the status signal C are the same. If it is determined that the information of the status signal A and the information of the status signal C are the same, the process proceeds to step S14. If it is determined that the information of the status signal A and the information of the status signal C are different, the process proceeds to step S15.

[0048] In step S14, the control unit 72 adopts the status signal A from among the three status signals in the signal group, and then ends the majority decision process.

[0049] In step S15, the control unit 72 determines whether the information of the status signal B is the same as the information of the status signal C. If it is determined that the information of the status signal B is the same as the information of the status signal C, the process proceeds to step S16. If it is determined that the information of the status signal B is different from the information of the status signal C, the process proceeds to step S17.

[0050] In step S16, the control unit 72 adopts the status signal B from the three status signals in the signal group, and then ends the majority decision process.

[0051] In step S17, the control unit 72 adopts the status signal adopted in the previous majority decision process as the status signal for the current majority decision process, and then ends the majority decision process.

[0052] [Signal group transmission processing] 6 is a flowchart showing the signal group transmission performed in the drive circuit 70. The drive circuit 70 repeatedly executes the signal group transmission process at a predetermined cycle.

[0053] In step S21, the drive circuit 70 judges whether or not the drive circuit 70 has been selected as a communication partner of the control unit 72. When the CS signal of the communication bus 74 connecting the control unit 72 and the drive circuit 70 is "0", the drive circuit 70 judges that the drive circuit 70 has been selected as a communication partner of the control unit 72. When the CS signal of the communication bus 74 connecting the control unit 72 and the drive circuit 70 is "1", the drive circuit 70 judges that the drive circuit 70 has not been selected as a communication partner of the control unit 72. When it is judged that the drive circuit 70 has been selected as a communication partner of the control unit 72, the process proceeds to step S22. When it is judged that the drive circuit 70 has not been selected as a communication partner of the control unit 72, the signal group transmission process is terminated.

[0054] In step S22, the drive circuit 70 transmits a status signal to the control unit 72 using the MISO of the communication bus 74. Thereafter, the signal group transmission process ends.

[0055] In addition to the above disclosure, the following notes are also disclosed.

[0056] (Appendix 1) A control device (12) for an internal combustion engine (10) having a throttle drive unit (24) that drives a throttle valve (22), comprising a control unit (72) that controls the internal combustion engine, and a drive circuit (70) that drives the throttle drive unit, the drive circuit transmits a signal group consisting of a series of status signals indicating a state of the drive circuit to the control unit at predetermined intervals, and the control unit controls the internal combustion engine based on the status signal that occupies the majority of the multiple status signals by making a majority decision on the multiple status signals included in the received signal group. With this configuration, even if noise is mixed into some of the multiple status signals included in the signal group, the control unit can appropriately control the internal combustion engine.

[0057] (Appendix 2) In the control device for an internal combustion engine described in Supplementary Note 1, the group of signals includes an odd number of the state signals. With this configuration, the control unit can reliably make a majority decision.

[0058] (Appendix 3) In the control device for an internal combustion engine described in Supplementary Note 1, the internal combustion engine may have an ignition plug (36) that ignites a mixture of fuel and air, an ignition interval at which the spark plug ignites the mixture may vary depending on a rotation speed of the internal combustion engine, and the predetermined period may coincide with the ignition interval when the rotation speed of the internal combustion engine is a predetermined rotation speed. With this configuration, even if noise is mixed into the state signal every time the drive circuit transmits a group of signals, the control unit can appropriately control the internal combustion engine.

[0059] (Appendix 4) A method for controlling an internal combustion engine having a throttle drive unit that drives a throttle valve, the method comprising: a transmission step in which a drive circuit that drives the throttle drive unit transmits a signal group including a series of status signals indicating a state of the drive circuit to a control unit that controls the internal combustion engine at a predetermined cycle, a reception step in which the control unit receives the signal group, and a control step in which the control unit performs a majority decision on the multiple status signals included in the received signal group, thereby controlling the internal combustion engine based on the status signal that occupies the majority of the multiple status signals. With this configuration, even if noise is mixed into some of the multiple status signals included in the signal group, the control unit can appropriately control the internal combustion engine.

[0060] The present invention is not limited to the above disclosure, and various configurations can be adopted without departing from the gist of the present invention. [Explanation of symbols]

[0061] 10: internal combustion engine; 12: control device; 22: throttle valve; 24: throttle drive section; 36: ignition plug; 70: drive circuit; 72: control section

Claims

1. A control device for an internal combustion engine having a throttle drive unit that drives a throttle valve, A control unit that controls the internal combustion engine; A drive circuit that drives the throttle drive unit; Equipped with the drive circuit transmits a signal group including a series of status signals indicating a status of the drive circuit to the control unit at predetermined intervals; The control unit controls the internal combustion engine based on the status signal that accounts for the majority of the multiple status signals included in the received signal group.

2. 2. The control device for an internal combustion engine according to claim 1, A control device for an internal combustion engine, wherein the group of signals includes an odd number of the status signals.

3. 2. The control device for an internal combustion engine according to claim 1, The internal combustion engine has a spark plug that ignites a mixture of fuel and air, an ignition interval at which the spark plug ignites the air-fuel mixture is changed according to a rotation speed of the internal combustion engine; A control device for an internal combustion engine, wherein the predetermined period corresponds to the ignition interval when the rotation speed of the internal combustion engine is a predetermined rotation speed.

4. A method for controlling an internal combustion engine having a throttle drive unit that drives a throttle valve, comprising: a transmission step in which a drive circuit that drives the throttle drive unit transmits a signal group including a series of status signals indicating a state of the drive circuit to a control unit that controls the internal combustion engine at predetermined intervals; a receiving step in which the control unit receives the group of signals; a control step in which the control unit performs a majority decision on a plurality of the status signals included in the received signal group, thereby controlling the internal combustion engine based on the status signal that occupies a majority of the plurality of the status signals; A method for controlling an internal combustion engine comprising:

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