Internal combustion engine control device

Abstract

In this internal combustion engine control device 100, during a process for calculating a throttle opening estimated value, a control unit 151 applies the throttle opening estimated value defined by using an intake pressure when the intake pressure that serves as a load correspondence value is equal to or less than a predetermined threshold, and applies the throttle opening estimated value defined by using a load correspondence value other than the intake pressure, when the intake pressure is larger than the predetermined threshold.

Description

Internal combustion engine control device

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

[0002] In recent years, when determining whether or not there is an abnormality in a throttle opening sensor that detects the throttle opening, which is the opening of the throttle valve of an internal combustion engine mounted on a vehicle, etc., a configuration is sometimes adopted in which an estimated throttle opening value is calculated to compare with the throttle opening value detected by the throttle opening sensor.

[0003] Under these circumstances, Patent Document 1 relates to a control device for a motorcycle and a vehicle, and discloses a configuration including actual opening acquisition units 11a, 11b that acquire an actual opening of a throttle valve of an electronic throttle of an internal combustion engine, an intake pressure acquisition unit 12 that acquires an intake pressure of the internal combustion engine, a rotational speed acquisition unit 13 that acquires the rotational speed of the internal combustion engine, an estimated opening calculation unit 14 that calculates an estimated opening of the throttle valve in accordance with the acquired intake pressure and rotational speed, a used opening determination unit 16 that determines an opening to be used as a feedback value in accordance with the estimated opening when the actual opening satisfies a malfunction condition, and a target opening determination unit 17 that restricts the generation of a target opening that exceeds a predetermined upper limit value when the actual opening satisfies a malfunction condition, one of which is a case where the actual opening differs from the estimated opening, and in which the estimated opening is calculated from the acquired intake pressure and rotational speed using a map or an arithmetic expression that associates the intake pressure, rotational speed, and estimated opening.

[0004] JP 2015-45284 A

[0005] However, according to the study by the present inventors, although the configuration of Patent Document 1 calculates the estimated opening by previously associating the intake pressure, the rotation speed, and the estimated opening, it has been found that when the estimated opening is calculated in correspondence with the intake pressure and the rotation speed, when the intake pressure is relatively low, an estimated value with sufficient accuracy for practical use can be obtained, but when the intake pressure is relatively high, an estimated value with sufficient accuracy for practical use cannot be obtained. In other words, it is believed that the configuration of Patent Document 1 has room for improvement in this respect.

[0006] The present invention has been made in light of the above considerations, and an object of the present invention is to provide an internal combustion engine control device that can obtain an estimated value of the throttle opening with sufficient accuracy for practical use.

[0007] In order to achieve the above object, one aspect of the present invention is an internal combustion engine control device that includes a control unit that executes a calculation process of a throttle opening estimation value, which is an estimate of the throttle opening, which is the opening of a throttle valve of the internal combustion engine, using a load correspondence value that corresponds to the load of the internal combustion engine, wherein in the calculation process, when the intake pressure as the load correspondence value is equal to or lower than a predetermined threshold, the control unit applies the throttle opening estimation value determined using the intake pressure, and when the intake pressure is greater than the predetermined threshold, applies the throttle opening estimation value determined using the load correspondence value other than the intake pressure.

[0008] According to an internal combustion engine control device of one aspect of the present invention, in the process of calculating the throttle opening estimated value, the control unit applies a throttle opening estimated value determined using the intake pressure when the intake pressure as a load corresponding value is equal to or lower than a predetermined threshold, while applying a throttle opening estimated value determined using a load corresponding value other than the intake pressure when the intake pressure is greater than the predetermined threshold.This makes it possible to switch the throttle opening estimated value for the predetermined intake pressure threshold, and to obtain a throttle opening estimated value with high accuracy that can be used appropriately in practical use.

[0009] Fig. 1 is a schematic diagram showing the configuration of an internal combustion engine control device according to an embodiment of the present invention, together with an internal combustion engine to which the same is applied. Fig. 2 is a schematic diagram showing an example of table data including a predetermined threshold value used in the calculation process of a throttle opening estimated value executed by the internal combustion engine control device according to this embodiment. Fig. 3A is a schematic diagram showing an example of data used in a region equal to or less than the predetermined threshold value in the table data shown in Fig. 2. Fig. 3B is a schematic diagram showing an example of data used in a region greater than the predetermined threshold value in the table data shown in Fig. 2. Fig. 4 is a flowchart showing an example of an abnormality response control process including the calculation process of a throttle opening estimated value executed by the internal combustion engine control device according to this embodiment.

[0010] Hereinafter, an internal combustion engine control device according to an embodiment of the present invention will be described in detail with reference to the drawings as appropriate.

[0011] <Configuration of Internal Combustion Engine> First, with reference to FIG. 1, the configuration of an internal combustion engine to which the internal combustion engine control device of this embodiment is applied will be described in detail.

[0012] FIG. 1 is a schematic diagram showing the configuration of an internal combustion engine control device according to this embodiment, together with an internal combustion engine to which the control device is applied.

[0013] As shown in FIG. 1 , the internal combustion engine 1 is typically a four-stroke reciprocating internal combustion engine mounted on a vehicle such as a motorcycle (not shown), and its operating state is controlled by an internal combustion engine control device 100. The internal combustion engine 1 includes a cylinder block 2. While the internal combustion engine 1 is shown in the figure as having only a single cylinder 2 a for ease of explanation, the internal combustion engine 1 may include multiple cylinders 2 a, and the cylinders 2 a may be arranged in an in-line, horizontally opposed, V-type, or other configuration. The internal combustion engine 1 is typically water-cooled, and a water temperature sensor 101 is provided in a cooling water passage 3 in the side wall of the cylinder block 2 to detect the temperature of the cooling water flowing through the cooling water passage 3. The water temperature sensor 101 outputs an electrical signal, exhibiting a voltage corresponding to the temperature of the cooling water flowing through the cooling water passage in the side wall of the cylinder block 2, to the internal combustion engine control device 100. If the internal combustion engine 1 is an air-cooled type, a temperature sensor (not shown) capable of detecting the temperature of the internal combustion engine 1 will be provided in the cylinder block 2 or the like instead of the water temperature sensor 101 .

[0014] A piston 4 is disposed inside the cylinder block 2. The piston 4 is connected to a crankshaft 6 via a connecting rod 5. A reluctor 7 is provided on the crankshaft 6, coaxially rotating with the crankshaft 6. A plurality of teeth 7a are provided on the outer periphery of the reluctor 7, arranged in a predetermined circumferential pattern. A crank angle sensor 102 is provided near the plurality of teeth 7a in a lower case (not shown) attached to the lower part of the cylinder block 2. The crank angle sensor 102 detects the rotation angle (rotational position) of the crankshaft 6, which is the rotational axis of the crankshaft 6 of the internal combustion engine 1, so that the internal combustion engine control device 100 can calculate the rotational speed (internal combustion engine rotation speed: number of revolutions) of the crankshaft and the position of the piston 4. The crank angle sensor 102 outputs an electrical signal, exhibiting high or low voltage, to the internal combustion engine control device 100, corresponding to the plurality of teeth 7a of the reluctor 7, which rotate with the rotation of the crankshaft 6, and the recesses between them.

[0015] A cylinder head 8 is attached to the top of the cylinder block 2. The inner wall surface of the cylinder block 2, the upper surface of the piston 4, and the inner wall surface of the cylinder head 8 cooperate to define an internal space which serves as a combustion chamber 9.

[0016] The cylinder block 2 and the cylinder head 8 are provided with a spark plug 10 for each cylinder 2a, which ignites an air-fuel mixture produced from fuel and air in the combustion chamber 9. The ignition operation of the spark plug 10 is controlled by the internal combustion engine control device 100, which controls the supply of electricity to an ignition coil (not shown).

[0017] The cylinder head 8 is provided with an intake valve 12 that freely opens and closes communication between the combustion chamber 9 and an intake passage 11a. The intake passage 11a is formed in the cylinder head 8 and an intake pipe 11 attached to the cylinder head 8. The intake pipe 11 is provided with a fuel injection valve 13 that injects fuel into the intake passage 11a and a throttle valve 14a that is located upstream of the fuel injection valve 13 and is a component of a throttle device 14. The intake pipe 11 is provided with an intake pressure sensor 103 between the intake valve 12 and the throttle valve 14a that detects the pressure (intake pressure) of air flowing into the intake pipe 11. The intake pressure sensor 103 outputs an electrical signal exhibiting a voltage corresponding to the intake pressure to the internal combustion engine control device 100. A throttle opening sensor 104 that detects the opening degree of the throttle valve 14a is attached to the main body of the throttle device 14, etc. The throttle opening sensor 104 outputs an electrical signal exhibiting a voltage corresponding to the opening of the throttle valve 14a (throttle opening) to the internal combustion engine control device 100. The fuel injection operation (valve opening operation) of the fuel injection valve 13 is controlled by the internal combustion engine control device 100 by controlling the supply of electricity to a solenoid valve (not shown). Here, the throttle opening detection system is a concept that includes not only the throttle opening sensor 104 but also an input circuit provided in the internal combustion engine control device 100 to receive the electrical signal output from the throttle opening sensor 104, and an electrical path such as electrical wiring between the throttle opening sensor 104 and the input circuit of the internal combustion engine control device 100. It should be noted that the fuel injection valve 13 may be a type that injects fuel directly into the combustion chamber 9.

[0018] An exhaust pipe 15 is attached to the cylinder head 8 on the opposite side of the intake pipe 11. An exhaust passage 15a communicating with the combustion chamber 9 is formed within the cylinder head 8 and the exhaust pipe 15. The cylinder head 8 is also provided with an exhaust valve 16 that freely opens and closes communication between the combustion chamber 9 and the exhaust passage 15a. A catalyst 17, typically a three-way catalyst, is provided in the exhaust pipe 15 downstream of the exhaust valve 16 to purify the exhaust gas discharged from the combustion chamber 9. An O2 sensor 105 is provided upstream of and adjacent to the catalyst 17 to detect the oxygen concentration in the exhaust gas. The O2 sensor 105 outputs an electrical signal, exhibiting a voltage corresponding to the oxygen concentration in the exhaust gas upstream of the catalyst 17, to the internal combustion engine control device 100. The O2 sensor may be provided not only upstream of the catalyst 17 but also downstream of the catalyst 17.

[0019] An accelerator opening sensor 106 is attached to a steering wheel or the like (not shown) of the vehicle, and detects the amount of operation (accelerator opening) of an accelerator grip or other accelerator operating member (not shown) of the vehicle. The accelerator opening sensor 106 outputs an electrical signal exhibiting a voltage corresponding to the accelerator opening to the internal combustion engine control device 100. In addition, a vehicle speed sensor 107 is attached to the front wheels (not shown) which are driven wheels of the vehicle, and the vehicle speed sensor 107 detects the rotation speed of the front wheels so that the internal combustion engine control device 100 calculates the vehicle speed. The vehicle speed sensor 107 outputs an electrical signal exhibiting a voltage corresponding to the rotation speed of the front wheels to the internal combustion engine control device 100. Note that the vehicle speed sensors may be attached not only to the front wheels but also to the rear wheels. Furthermore, the throttle device 14 is typically an electronically controlled type in which the throttle opening of the throttle valve 14a is controlled by the internal combustion engine control device 100 via a throttle motor, but it may also be a mechanical type in which the throttle opening changes directly and mechanically in response to the accelerator pedal position. If the throttle device 14 is a mechanical type, the throttle opening is determined only in accordance with the accelerator pedal position, whereas if the throttle device 14 is an electronically controlled type, the throttle opening is controlled based on the accelerator pedal position as well as other parameters.

[0020] <Configuration of Internal Combustion Engine Control Device> Next, with reference to FIGS. 2 to 3B in addition to FIG. 1, the configuration of the internal combustion engine control device 100 according to this embodiment will be described in detail.

[0021] Fig. 2 is a schematic diagram showing an example of table data including a predetermined threshold value used in the calculation process of the throttle opening estimated value executed by the internal combustion engine control device in this embodiment. Fig. 3A is a schematic diagram showing an example of data used in a region equal to or less than the predetermined threshold value in the table data shown in Fig. 2. Fig. 3B is a schematic diagram showing an example of data used in a region greater than the predetermined threshold value in the table data shown in Fig. 2.

[0022] First, as shown in FIG. 1, an internal combustion engine control device 100 is configured by an ECU (Electronic Control Unit), which is an electronic control device mounted on a vehicle and controls the operation of an internal combustion engine 1 .

[0023] Such an ECU is an arithmetic processing device consisting of a CPU (Central Processing Unit) 150, a memory (not shown), etc., in which the necessary control / processing programs and control / processing data are stored, and the CPU 150, the memory, etc. constitute a microcomputer.

[0024] Specifically, the CPU 150 includes a control unit 151. The control unit 151 controls the operation of the various control targets, such as the spark plug 10, the fuel injection valve 13, and the throttle valve 14a, based on values ​​acquired from electrical signals output from various sensors, namely, the water temperature sensor 101, the crank angle sensor 102, the intake pressure sensor 103, the throttle opening sensor 104, the O2 sensor 105, the accelerator opening sensor 106, and the vehicle speed sensor 107, and also reads out necessary control / processing programs and control / processing data from memory, and executes the control / processing programs to thereby control the operating state of the internal combustion engine 1. Note that in the drawing, the control unit 151 is shown as a functional block when the CPU 150 executes the control / processing programs.

[0025] The control unit 151 also executes a process for calculating a throttle opening estimated value, which is an estimated value of the throttle opening, using a load corresponding value corresponding to the load on the internal combustion engine 1 (throttle opening estimated value calculation process). The load corresponding value increases or decreases according to an increase or decrease in the load on the internal combustion engine 1. Typical examples of such load corresponding values ​​include the intake pressure calculated by the control unit 151 based on an electrical signal output from the intake pressure sensor 103, the angular acceleration of the crankshaft 6 of the internal combustion engine 1 (internal combustion engine angular acceleration) calculated by the control unit 151 based on an electrical signal output from the crank angle sensor 102, and, if the throttle device 14 is a mechanical type, the accelerator opening calculated by the control unit 151 based on an electrical signal output from the accelerator opening sensor 106. The following description will be given taking the intake pressure and the internal combustion engine angular acceleration as examples of such load corresponding values.

[0026] In the throttle opening estimated value calculation process, the control unit 151 applies a throttle opening estimated value previously determined using the intake pressure when the intake pressure as the load corresponding value is equal to or lower than a predetermined threshold, while applying a throttle opening estimated value previously determined using a load corresponding value other than the intake pressure when the intake pressure is higher than the predetermined threshold. Note that, in this case, the control unit 151 may apply a throttle opening estimated value previously determined using the intake pressure when the intake pressure as the load corresponding value is lower than the predetermined threshold, while applying a throttle opening estimated value previously determined using a load corresponding value other than the intake pressure when the intake pressure is higher than the predetermined threshold. This makes it possible to obtain a throttle opening estimated value with high accuracy that is suitable for practical use.

[0027] In this case, when the intake pressure is greater than a predetermined threshold, the control unit 151 preferably applies a throttle opening estimate that is previously defined using the angular acceleration of the internal combustion engine as a load-corresponding value other than the intake pressure. This makes it possible to obtain a more accurate throttle opening estimate that can be used appropriately in practice. The following description will be given taking the intake pressure and the angular acceleration of the internal combustion engine as examples of the load-corresponding value.

[0028] Specifically, it is preferable that the predetermined threshold value be determined in accordance with the internal combustion engine rotation speed and the intake pressure, the throttle opening estimate value applied when the intake pressure is equal to or less than the predetermined threshold value be determined in accordance with the internal combustion engine rotation speed and the intake pressure, and the throttle opening estimate value applied when the intake pressure is greater than the predetermined threshold value be determined in accordance with the internal combustion engine rotation speed and the internal combustion engine angular acceleration. This makes it possible to reliably obtain a more accurate throttle opening estimate value that is suitable for practical use by appropriately reflecting the influence of the internal combustion engine rotation speed.

[0029] Furthermore, the control unit 151 preferably calculates the throttle opening based on the electrical signal from the throttle opening sensor 104, determines whether or not there is an abnormality in the throttle opening detection system including the throttle opening sensor 104 based on the estimated throttle opening value and the throttle opening, and performs abnormality response control to address the abnormality if an abnormality is determined. Typical examples of such abnormality response control include stopping the ignition operation of the spark plug 10, stopping the fuel injection operation of the fuel injection valve 13, and, if the throttle device 14 is electronically controlled, fully closing the throttle valve 14a. This allows for appropriate abnormality response control to address an abnormality in the throttle opening detection system with a simple configuration that does not require multiple throttle opening sensors.

[0030] 2, which is used by the control unit 151 in the throttle opening estimated value calculation process, defines a two-axis orthogonal coordinate system with the internal combustion engine rotation speed on the horizontal axis and the intake air pressure on the vertical axis, and defines a predetermined threshold value for the intake air pressure that is set to gradually decrease as the internal combustion engine rotation speed increases. Note that, for convenience, the predetermined threshold value is shown in the figure as a value that forms a single continuous straight line, but it may also be a value that forms a single continuous curve, or may be a set of multiple discrete points (values).

[0031] Here, as shown in Fig. 2, when the coordinate value consisting of the internal combustion engine rotation speed value and the intake pressure value is in a lower region below a predetermined threshold, a throttle opening estimated value defined using the intake pressure is applied, while when the coordinate value consisting of the internal combustion engine rotation speed value and the intake pressure value is in an upper region above the predetermined threshold, a throttle opening estimated value defined using the internal combustion engine angular acceleration is applied. Note that in Fig. 2, when the coordinate value consisting of the internal combustion engine rotation speed value and the intake pressure value is in a region below the predetermined threshold, a throttle opening estimated value defined using the internal combustion engine angular acceleration may be applied, while when the coordinate value consisting of the internal combustion engine rotation speed value and the intake pressure value is in a region above the predetermined threshold, a throttle opening estimated value defined using the internal combustion engine angular acceleration may be applied.

[0032] 3A, a two-axis Cartesian coordinate system is defined, with the horizontal axis representing the internal combustion engine rotation speed and the vertical axis representing the intake pressure, and a plurality of throttle opening estimates are defined in accordance with the internal combustion engine rotation speed and the intake pressure, such that the intake pressure decreases as the internal combustion engine rotation speed increases. The diagram shows, as representative examples, a fully closed throttle opening estimate TH0 indicating that the throttle opening is zero, a 20% throttle opening estimate TH20 indicating that the throttle opening is 20%, a 40% throttle opening estimate TH40 indicating that the throttle opening is 40%, a 60% throttle opening estimate TH60 indicating that the throttle opening is 60%, and an 80% throttle opening estimate TH80 indicating that the throttle opening is 80%. These throttle opening estimated values ​​were obtained by noting that there is a correlation between the intake pressure value and the throttle opening value while corresponding to the internal combustion engine rotation speed value. Specifically, in this correlation, the internal combustion engine rotation speed value and the intake pressure value were each changed, and the throttle opening estimated values ​​TH0 to TH80 corresponding to these internal combustion engine rotation speed values ​​and intake pressure values ​​were each obtained.

[0033] However, according to the inventor's study of Figure 3A, it has been found that in region A, where the intervals between adjacent throttle opening estimates relative to the intake pressure are relatively wide, a highly accurate throttle opening estimate corresponding to the internal combustion engine speed and the intake pressure can be obtained, whereas in the remaining region, where the intervals between adjacent throttle opening estimates relative to the intake pressure are only relatively narrow, a highly accurate throttle opening estimate corresponding to the internal combustion engine speed and the intake pressure cannot be obtained. Therefore, when the intake pressure is in a region equal to or less than the predetermined intake pressure threshold value in Figure 2 according to the internal combustion engine speed, the throttle opening estimate is calculated using the throttle opening estimates TH0 to TH40 in region A. Note that, taking into consideration the pulsation of the intake pressure, it is typically preferable to use the lowest value (bottom value) of the intake pressure as the intake pressure value for calculating the throttle opening estimate.

[0034] 3B , a two-axis Cartesian coordinate system is defined, with the horizontal axis representing the rotational speed of the internal combustion engine 1 (internal combustion engine rotational speed) and the vertical axis representing the internal combustion engine angular acceleration. A plurality of throttle opening estimates are defined, each of which decreases as the internal combustion engine rotational speed increases, depending on the values ​​of the internal combustion engine rotational speed and the internal combustion engine angular acceleration. In the figure, throttle opening estimates TH0 to TH80 are shown as representative examples. These throttle opening estimates were obtained by focusing on the correlation between the value of the internal combustion engine angular acceleration and the value of the throttle opening, while corresponding to the value of the internal combustion engine rotational speed. Specifically, the throttle opening estimates TH0 to TH80 corresponding to the values ​​of the internal combustion engine rotational speed and the internal combustion engine angular acceleration were determined while varying the values ​​of the internal combustion engine rotational speed and the internal combustion engine angular acceleration, respectively, based on this correlation.

[0035] However, according to the inventor's study of Figure 3B, it has been found that in region B, where the interval between adjacent throttle opening estimates with respect to the internal combustion engine angular acceleration is relatively wide, a throttle opening estimate with high accuracy corresponding to the values ​​of the internal combustion engine rotation speed and the values ​​of the internal combustion engine angular acceleration can be obtained, whereas in the remaining region, where the interval between adjacent throttle opening estimates with respect to the internal combustion engine angular acceleration is only relatively narrow, a throttle opening estimate with high accuracy corresponding to the values ​​of the internal combustion engine rotation speed and the values ​​of the internal combustion engine angular acceleration cannot be obtained. Furthermore, since the internal combustion engine angular acceleration, particularly during the compression stroke of the internal combustion engine 1, is correlated with the intake pressure, it is possible to switch between a throttle opening estimate defined using the intake pressure and a throttle opening estimate defined using the internal combustion engine angular acceleration for the predetermined intake pressure threshold in Figure 2. 2, when the intake pressure value is greater than the predetermined intake pressure threshold value, the throttle opening estimated value TH60 and TH80 in this region B are applied to calculate the throttle opening estimated value. The value of the internal combustion engine angular acceleration is typically calculated based on the difference between the time required for the intake stroke of the internal combustion engine 1 and the time required for the compression stroke of the internal combustion engine 1. Although each of the throttle opening estimated values ​​TH0 to TH80 is shown as a single continuous straight line in FIGS. 3A and 3B for convenience, they may be values ​​that form a single continuous curve, or may be a set of multiple discrete points (values).

[0036] Furthermore, when throttle opening estimates TH0 to TH80 are applied in this manner in Figure 2, the predetermined threshold value may be defined to extend between throttle opening estimates TH40 and TH60. Note that even when the number of throttle opening estimates in Figures 3A and 3B is increased, thereby increasing the number of throttle opening estimates in Figure 2, the predetermined threshold value will still be defined to extend between the largest throttle opening estimate in region A in Figure 3A and the smallest throttle opening estimate in region B in Figure 3B.

[0037] <Example of abnormality response control processing including throttle opening estimated value calculation processing> An example of abnormality response control processing in which the internal combustion engine control device 100 having the above configuration executes abnormality response control will be described in detail below, further with reference to FIG. 4.

[0038] FIG. 4 is a flowchart showing an example of an abnormality response control process including a calculation process of a throttle opening degree estimated value executed by the internal combustion engine control device in this embodiment.

[0039] 4 typically starts when a power switch (not shown) of the vehicle is switched from an off state to an on state and the CPU 150 of the internal combustion engine control device 100 is put into operation, and the abnormality response control process proceeds to the processing of step S1. Note that this abnormality response control process is repeatedly executed by reading the necessary control program and control data from memory at predetermined intervals, such as every 10 ms, while the CPU 150 is in operation.

[0040] In the process of step S1, the control unit 151 calculates the throttle opening. Specifically, the control unit 151 calculates the throttle opening based on an electrical signal output from the throttle opening sensor 104 of the throttle opening detection system. This completes the process of step S1, and the abnormality response control process proceeds to the process of step S2.

[0041] In the process of step S2, the control unit 151 calculates the intake pressure. Specifically, the control unit 151 calculates the intake pressure based on the electrical signal output from the intake pressure sensor 103. This completes the process of step S2, and the abnormality response control process proceeds to the process of step S3.

[0042] In the process of step S3, the control unit 151 calculates the internal combustion engine rotation speed. Specifically, the control unit 151 calculates the internal combustion engine rotation speed based on the electrical signal output from the crank angle sensor 102. This completes the process of step S3, and the abnormality response control process proceeds to the process of step S4.

[0043] In the processing of step S4, the control unit 151 calculates the angular velocity difference between the intake stroke angular velocity calculated from the time required for the intake stroke of the internal combustion engine 1 and the compression stroke angular velocity calculated from the time required for the compression stroke of the internal combustion engine 1, and calculates the internal combustion engine angular acceleration by dividing this angular velocity difference by the time required for the compression stroke of the internal combustion engine 1. This completes the processing of step S4, and the abnormality response control processing proceeds to the processing of step S5.

[0044] In the process of step S5, the control unit 151 obtains a throttle opening estimate defined using the intake pressure. Specifically, the control unit 151 reads the table data shown in Fig. 3A from memory and obtains a throttle opening estimate included in the region of the intake pressure equal to or less than a predetermined threshold value (in the figure, the throttle opening estimate values ​​TH0 to TH40 defined using the intake pressure). This completes the process of step S5, and the abnormality response control process proceeds to the process of step S6.

[0045] In the process of step S6, the control unit 151 acquires a throttle opening estimate defined using the internal combustion engine angular acceleration. Specifically, the control unit 151 reads the table data shown in Fig. 3B from memory and acquires a throttle opening estimate included in a region where the intake pressure is greater than a predetermined threshold value (in the figure, the throttle opening estimate values ​​TH60 and TH80 defined using the internal combustion engine angular acceleration). This completes the process of step S6, and the abnormality response control process proceeds to the process of step S7.

[0046] In the process of step S7, the control unit 151 determines whether the intake pressure is equal to or less than a predetermined threshold. Specifically, the control unit 151 reads the table data shown in FIG. 2 from the memory and determines whether the value of the intake pressure calculated in the process of step S2 is equal to or less than a predetermined threshold corresponding to the value of the internal combustion engine rotation speed calculated in the process of step S3. If the result of the determination is that the intake pressure is equal to or less than the predetermined threshold (step S7: Yes), the control unit 151 proceeds to the process of step S8 in the abnormality response control process. On the other hand, if the intake pressure is not equal to or less than the predetermined threshold (is greater than the predetermined threshold) (step S7: No), the control unit 151 proceeds to the process of step S9 in the abnormality response control process.

[0047] In the process of step S8, the control unit 151 selects, from the throttle opening estimated values ​​acquired in the process of step S5, the one having the shortest distance (including zero distance) from the coordinate value formed by the intake pressure value calculated in the process of step S2 and the internal combustion engine rotation speed value calculated in the process of step S3, and calculates it as the throttle opening estimated value. This completes the process of step S8, and the abnormality response control process proceeds to the process of step S10.

[0048] In the process of step S9, the control unit 151 selects, from the throttle opening estimated values ​​acquired in the process of step S6, the one having the shortest distance (including zero distance) from the coordinate value formed by the internal combustion engine angular acceleration acquired in the process of step S4 and the internal combustion engine rotation speed calculated in the process of step S3, and calculates it as the throttle opening estimated value. This completes the process of step S9, and the abnormality response control process proceeds to the process of step S10.

[0049] In step S10, the control unit 151 determines whether or not there is an abnormality in the throttle opening detection system, including the throttle opening sensor 104. Specifically, if the absolute value of the deviation between the throttle opening value calculated in step S1 and the throttle opening estimated value calculated in step S8 or step S9 is equal to or greater than a predetermined value, the control unit 151 determines that there is an abnormality in the throttle opening detection system. Otherwise, the control unit 151 determines that there is no abnormality in the throttle opening detection system. Note that instead of such deviation, the ratio between the throttle opening value and the throttle opening estimated value may be used, and the predetermined value may be either one written in the program or read from memory. If the determination results in an abnormality in the throttle opening detection system (step S10: Yes), the control unit 151 proceeds to step S11 in the abnormality response control process. On the other hand, if there is no abnormality in the throttle opening detection system (step S10: No), the current series of abnormality response control processes ends.

[0050] In the process of step S11, the control unit 151 executes abnormality response control. Specifically, the control unit 151 executes all or part of the following: stopping the ignition operation of the spark plug 10; stopping the fuel injection operation of the fuel injection valve 13; and, if the throttle device 14 is electronically controlled, setting the throttle opening of the throttle valve 14a to the fully closed position. This completes the process of step S11, and ends the current series of abnormality response control processes.

[0051] In the first aspect of the internal combustion engine control device 100 in this embodiment described above, in the process of calculating the throttle opening estimate, the control unit 151 applies a throttle opening estimate defined using the intake pressure when the intake pressure as a load corresponding value is below a predetermined threshold, while applying a throttle opening estimate defined using a load corresponding value other than the intake pressure when the intake pressure is greater than the predetermined threshold.This makes it possible to switch the throttle opening estimate for the predetermined threshold value of the intake pressure, and to obtain a throttle opening estimate with high accuracy that can be used appropriately in practical use.

[0052] Furthermore, in the second aspect of the internal combustion engine control device 100 of this embodiment, in addition to the first aspect, when the intake pressure is greater than a predetermined threshold, the control unit 151 applies a throttle opening estimation value determined using the internal combustion engine angular acceleration, which is a load-corresponding value other than the intake pressure, so that a more accurate throttle opening estimation value that can be appropriately used in practical applications can be obtained.

[0053] Furthermore, in the third aspect of the internal combustion engine control device 100 of this embodiment, in addition to the second aspect, the predetermined threshold is defined according to the internal combustion engine rotation speed and the intake pressure, the throttle opening estimated value applied when the intake pressure is equal to or lower than the predetermined threshold is defined according to the internal combustion engine rotation speed and the intake pressure, and the throttle opening estimated value applied when the intake pressure is greater than the predetermined threshold is defined according to the internal combustion engine rotation speed and the internal combustion engine angular acceleration. Therefore, it is possible to reliably obtain a more accurate throttle opening estimated value that can be used appropriately in practical applications by appropriately reflecting the influence of the internal combustion engine rotation speed.

[0054] Furthermore, in a third aspect of the internal combustion engine control device 100 of this embodiment, in addition to any of the first to third aspects, the control unit 151 calculates the throttle opening based on an electrical signal from the throttle opening sensor 104, which outputs an electrical signal according to the throttle opening, and determines whether or not there is an abnormality in the throttle opening detection system including the throttle opening sensor 104 based on the throttle opening estimate value and the throttle opening, and if it determines that there is an abnormality, executes abnormality response control corresponding to the abnormality.Therefore, with a simple configuration that does not use multiple throttle opening sensors, it is possible to appropriately execute abnormality response control that responds to an abnormality in the throttle opening detection system.

[0055] The present invention is not limited to the above-described embodiments in terms of the type, shape, arrangement, number, etc. of the components, and it goes without saying that the components can be appropriately modified within the scope of the gist of the invention, such as by appropriately replacing them with components that have equivalent effects.

[0056] As described above, the present invention can provide an internal combustion engine control device that can obtain an estimated value of throttle opening with sufficient accuracy for practical use, and because of its versatile and universal nature, it is expected to be widely applicable to internal combustion engine control devices for motorcycles.

[0057] DESCRIPTION OF SYMBOLS 1...internal combustion engine 2...cylinder block 2a...cylinder 3...coolant passage 4...piston 5...connecting rod 6...crankshaft 7...reluctor 7a...tooth portion 8...cylinder head 9...combustion chamber 10...spark plug 11...intake pipe 11a...intake passage 12...intake valve 13...fuel injection valve 14...throttle device 14a...throttle valve 15...exhaust pipe 15a...exhaust passage 16...exhaust valve 17...catalyst 100...internal combustion engine control device 101...water temperature sensor 102...crank angle sensor 103...intake pressure sensor 104...throttle opening sensor 105...O2 sensor 106...accelerator opening sensor 107...vehicle speed sensor 150...CPU 151...control unit

Claims

1. An internal combustion engine control device having a control unit that executes a calculation process of a throttle opening estimation value, which is an estimate of the throttle opening, which is the opening of a throttle valve of an internal combustion engine, using a load corresponding value corresponding to the load of the internal combustion engine, wherein in the calculation process, the control unit applies the throttle opening estimation value defined using the intake pressure when the intake pressure as the load corresponding value is equal to or lower than a predetermined threshold, and applies the throttle opening estimation value defined using the load corresponding value other than the intake pressure when the intake pressure is greater than the predetermined threshold.

2. The internal combustion engine control device according to claim 1, characterized in that, when the intake pressure is greater than the predetermined threshold value, the control unit applies the throttle opening estimated value defined using the angular acceleration of the internal combustion engine, which is a load corresponding value other than the intake pressure.

3. The internal combustion engine control device as described in claim 2, characterized in that the predetermined threshold is determined according to the rotational speed and intake pressure of the internal combustion engine, the throttle opening estimation value applied when the intake pressure is equal to or lower than the predetermined threshold is determined according to the rotational speed and the intake pressure, and the throttle opening estimation value applied when the intake pressure is greater than the predetermined threshold is determined according to the rotational speed and the angular acceleration.

4. The control unit of an internal combustion engine control device as described in claim 1 or 2, characterized in that it calculates the throttle opening based on an electrical signal from a throttle opening sensor that outputs an electrical signal corresponding to the throttle opening, determines whether or not there is an abnormality in the throttle opening detection system including the throttle opening sensor based on the throttle opening estimated value and the throttle opening, and if it determines that there is an abnormality, executes abnormality response control corresponding to the abnormality.

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