Internal combustion engine control device

Abstract

To provide an internal combustion engine control device capable of appropriately setting ignition timing of an ignition plug on a timing advance side on which no abnormality has occurred and thus stabilizing an internal combustion engine when an abnormality has occurred only in an ignition plug on a timing delay side out of the two ignition plugs provided in the internal combustion engine.SOLUTION: In an internal combustion engine control device 50, compared to ignition timing of a first ignition plug 10a on a timing advance side of ignition timing of a second ignition plug 10b when both of the first ignition plug 10a and the second ignition plug 10b are in the normal state, an ignition control section 151 performs setting so as to delay the ignition timing of the first ignition plug 10a on the timing advance side of the ignition timing of the second ignition plug 10b when the first ignition plug 10a is in the normal state and the second ignition plug 10b is in the abnormal state.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an internal combustion engine control device that controls the ignition operation of two spark plugs provided for each cylinder of an internal combustion engine mounted on a vehicle, and also controls the fuel injection operation of an injector provided for each cylinder.

Background Art

[0002] In recent years, in an internal combustion engine, in order to improve the ignition performance of the air-fuel mixture generated in the combustion chamber and improve various characteristics such as exhaust gas characteristics and fuel consumption characteristics, a configuration in which a plurality of spark plugs are provided for one cylinder may be adopted.

[0003] Under such circumstances, Patent Document 1 relates to an ignition timing control device for a multi-point ignition internal combustion engine, and discloses a configuration in which a plurality of ignition gaps 11 to 14 are arranged in one combustion chamber 1, and the ignition timings of each of the ignition gaps 11 to 14 are different from each other.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, according to the inventor's research, the configuration of Patent Document 1 discloses a configuration in which multiple ignition gaps 11 to 14 are arranged in one combustion chamber 1, and the ignition timings of each of the ignition gaps 11 to 14 are made different from each other. However, it does not consider the situation in which an abnormality occurs in any of the multiple ignition gaps 11 to 14. It does not disclose or suggest how to set the ignition timing in the remaining ignition gaps that are not abnormal when an abnormality occurs in any of the multiple ignition gaps 11 to 14. It is thought that the combustion of the internal combustion engine tends to become unstable due to inappropriate ignition timing, and there is room for improvement.

[0006] The present invention was made after the above considerations, and aims to provide an internal combustion engine control device that can stabilize the combustion of an internal combustion engine by appropriately setting the ignition timing of the advancing spark plug, which is not malfunctioning, when a malfunction occurs only in the retarding spark plug of the two spark plugs provided in the internal combustion engine. [Means for solving the problem]

[0007] To achieve the above objectives, the present invention provides an internal combustion engine control device comprising: an ignition control unit that controls the ignition operation by a first spark plug and a second spark plug provided for one cylinder of an internal combustion engine; and a fuel supply control unit that controls the fuel supply operation to the internal combustion engine, wherein the first ignition timing of the first spark plug is set to be advanced compared to the second ignition timing of the second spark plug, and the ignition control unit is set to retard the first ignition timing when the first spark plug is in a normal state and the second spark plug is in an abnormal state, compared to the first ignition timing when both the first spark plug and the second spark plug are in a normal state. When the first spark plug is in the normal state and the second spark plug is in the abnormal state, the first ignition timing after retarding the first spark plug is set within the range between the first ignition timing in the normal state for the first spark plug and the second ignition timing in the normal state for the second spark plug. The ignition control unit sets the first ignition timing, when the first spark plug is in the normal state and the second spark plug is in the abnormal state, to retard the timing according to the engine speed and throttle opening, by multiplying the first ignition timing, which is calculated according to the engine speed and throttle opening using the ignition timing map for when both the first and second spark plugs are in the normal state, by a correction coefficient calculated according to the engine speed and throttle opening using the correction coefficient map for when the first spark plug is in the normal state and the second spark plug is in the abnormal state.This will be the first phase. [Effects of the Invention]

[0009] According to the internal combustion engine control device of the first aspect of the present invention, the ignition control unit sets the ignition timing of the first spark plug to be retarded compared to the ignition timing of the second spark plug when both the first and second spark plugs are in a normal state, which is advanced compared to the ignition timing of the second spark plug when the first spark plug is in a normal state and the second spark plug is in an abnormal state. Furthermore, when the first spark plug is in a normal state and the second spark plug is in an abnormal state, the first ignition timing of the first spark plug after retardation is set within the range between the first ignition timing in the normal state of the first spark plug and the second ignition timing in the normal state of the second spark plug. By doing so, if a malfunction occurs only in the retarded spark plug of the two spark plugs installed in the internal combustion engine, the ignition timing of the advanced spark plug, which is not malfunctioning, can be appropriately set, thereby stabilizing the combustion of the internal combustion engine.

[0010] Furthermore, this invention 1 According to the internal combustion engine control device in this phase, the ignition control unit determines the ignition timing of the first spark plug when the first spark plug is in a normal state and the second spark plug is in an abnormal state. The first ignition timing, calculated according to the engine speed and throttle opening of the internal combustion engine using an ignition timing map for when both the first and second spark plugs are in a normal state, is multiplied by a correction coefficient calculated according to the engine speed and throttle opening using a correction coefficient map for when the first spark plug is in a normal state and the second spark plug is in an abnormal state. By setting the ignition timing to retard according to the engine speed and throttle opening of the internal combustion engine, if a malfunction occurs only in the retarded spark plug of the two spark plugs installed in the internal combustion engine, the ignition timing of the advanced spark plug, which is not malfunctioning, can be set more appropriately, thereby stabilizing the combustion of the internal combustion engine. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a schematic diagram showing the configuration of an internal combustion engine control device (hereinafter sometimes referred to as an engine control device) in an embodiment of the present invention, together with an internal combustion engine (hereinafter sometimes referred to as an engine). [Figure 2]Figure 2 shows an example of an ignition timing correction coefficient map used by the engine control device in this embodiment. Figure 2(a) shows an example of a correction coefficient map that is applied when only the second spark plug is faulty and has ignition timing correction coefficient values ​​defined according to the engine speed and throttle opening values. Figure 2(b) shows an example of a correction coefficient map that is applied when only the first spark plug is faulty and has ignition timing correction coefficient values ​​defined according to the engine speed and throttle opening values. [Figure 3] Figure 3 is a flowchart showing an example of the correction coefficient calculation process of the engine control device in this embodiment. [Modes for carrying out the invention]

[0012] Hereinafter, with appropriate reference to the drawings, the engine control device according to an embodiment of the present invention will be described in detail.

[0013] <Engine Configuration> First, with reference to Figure 1, the configuration of the engine to which the engine control device in this embodiment is applied will be described in detail.

[0014] Figure 1 is a schematic diagram showing the configuration of the engine control device in this embodiment, along with the engine.

[0015] As shown in Figure 1, the engine 1 is typically mounted in a vehicle such as a motorcycle (not shown), is a four-stroke reciprocating internal combustion engine, and its operating state is controlled by an engine control device 50, and it is equipped with a cylinder block 2. For the sake of explanation, the figure shows the engine 1 as having a single cylinder 2a configuration, but the engine 1 may have multiple cylinders 2a, and the arrangement of the cylinders 2a may be in series, horizontally opposed, V-type, etc. The engine 1 is typically water-cooled, and a water temperature sensor 101 is provided in a cooling water passage (not shown) within the side wall of the cylinder block 2 to detect the temperature of the cooling water flowing through the passage. If the engine 1 is air-cooled, a temperature sensor (not shown) capable of detecting the temperature of the engine 1 will be provided in the cylinder block 2, etc., instead of the water temperature sensor 101.

[0016] A piston 4 is located inside the cylinder block 2. The piston 4 is connected to the crankshaft 6 via a connecting rod 5. The crankshaft 6 is provided with a recurctor 7 that rotates coaxially with it. Multiple teeth 7a are erected on the outer surface of the recurctor 7, arranged in a predetermined pattern in the circumferential direction. Near the multiple teeth 7a, a crank angle sensor 102 is provided in the lower part of the cylinder block 2 (not shown) to detect the rotation angle of the crankshaft 6, so that the engine control device 50 can detect the rotational speed of the engine 1.

[0017] A cylinder head 8 is mounted on top of the cylinder block 2. The internal space defined by the cooperation of 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 forms the combustion chamber 9.

[0018] The cylinder block 2 and cylinder head 8 are provided with two spark plugs 10a and 10b for each cylinder 2a, which ignite the fuel-air mixture generated in the combustion chamber 9. The ignition operation of spark plugs 10a and 10b is controlled by the engine control device 50, which controls the supply of current to the respective ignition coils L1 and L2. Spark plugs 10a and 10b are typically mass-produced, commercially available spark plugs of the same specifications. In the figure, one of them is shown mounted on the cylinder block 2 and the other on the cylinder head 8. However, the mounting locations of spark plugs 10a and 10b are not particularly limited, as long as they can ignite the fuel-air mixture in the combustion chamber 9 in a practically equivalent manner. For example, both may be mounted on the cylinder block 2 or the cylinder head 8. Furthermore, the ignition timing of spark plugs 10a and 10b is set differently from each other, with one advancing the other.

[0019] The cylinder head 8 is provided with an intake valve 12 that allows the combustion chamber 9 and the intake passage 11a to be opened and closed. The intake passage 11a is formed in the cylinder head 8 and the intake pipe 11 mounted to the cylinder head 8. The intake pipe 11 is provided with a fuel injector 13 that injects fuel into the intake passage 11a, and a throttle valve 14, which is a component of a throttle device (not shown) and is located upstream of the fuel injector 13. The intake pipe 11 is provided with an intake pressure sensor 103 between the intake valve 12 and the throttle valve 14 to detect the pressure of the air flowing into the intake pipe 11 (intake pressure). A throttle opening sensor 104 that detects the degree of opening of the throttle valve 14 is mounted on the main body of the throttle device. The fuel injection operation (valve opening operation) of the fuel injector 13 is controlled by controlling the supply of power to its solenoid valve (not shown). The fuel injector 13 may also inject fuel directly into the combustion chamber 9.

[0020] Further, an exhaust pipe 15 is attached to the cylinder head 8 on the opposite side of the intake pipe 11, and an exhaust passage 15a communicating with the combustion chamber 9 is formed in the cylinder head 8 and the exhaust pipe 15. Further, an exhaust valve 16 is provided in the cylinder head 8 to communicably connect the combustion chamber 9 and the exhaust passage 15a in an openable and closable manner. A catalyst 109, typically a three-way catalyst, for purifying the exhaust gas discharged from the combustion chamber 9 is provided in the exhaust pipe 15 on the downstream side of the exhaust valve 16, and an O2 sensor 110 for detecting the oxygen concentration in the exhaust gas is provided on the upstream side thereof close to the catalyst 109.

[0021] The water temperature sensor 101 outputs an electric signal presenting 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 engine control device 50. The crank angle sensor 102 outputs an electric signal presenting a high and low voltage corresponding to the plurality of tooth portions 7a of the reluctor 7 that rotates with the rotation of the crankshaft 6 and the recesses therebetween to the engine control device 50. The intake pressure sensor 103 outputs an electric signal presenting a voltage corresponding to the pressure of the air flowing into the intake pipe 11 (intake pressure) to the engine control device 50. The throttle opening sensor 104 outputs an electric signal presenting a voltage corresponding to the opening of the throttle valve 14 (throttle opening) to the engine control device 50. Further, the O2 sensor 110 outputs an electric signal presenting a voltage corresponding to the oxygen concentration in the exhaust gas on the upstream side of the catalyst 109 to the engine control device 50. Note that reference numeral 120 denotes a vehicle speed sensor 120 that detects the vehicle speed from the rotational speed of the front wheels, which are the driven wheels of the vehicle, and the vehicle speed sensor 120 outputs an electric signal presenting a voltage corresponding to the vehicle speed to the engine control device 50.

[0022] <Configuration of Engine Control Device> Next, referring further to FIG. 2, the configuration of the engine control device 50 in the present embodiment will be described in detail.

[0023] Figure 2 shows an example of an ignition timing correction coefficient map used by the engine control device in this embodiment. Figure 2(a) shows an example of a correction coefficient map applied when the first spark plug is normal and only the second spark plug is abnormal, and which has an ignition timing correction coefficient value defined according to the engine speed and throttle opening. Figure 2(b) shows an example of a correction coefficient map applied when the second spark plug is normal and only the first spark plug is abnormal, and which has an ignition timing correction coefficient value defined according to the engine speed and throttle opening. For convenience, spark plug 10a may be described as the first spark plug and spark plug 10b as the second spark plug, but spark plug 10a may be described as the second spark plug and spark plug 10b as the first spark plug.

[0024] First, as shown in Figure 1, the engine control device 50 is composed of an ECU (Electronic Control Unit) 150, which is an electronic control device mounted on the vehicle that controls the operation of the engine 1.

[0025] The ECU150 is a processing unit including a microcomputer consisting of a CPU (Central Processing Unit) and memory, and has memory and timers (not shown in the diagram). The memory stores the necessary control and processing programs and control and processing data. The ECU150 controls the operating state of the engine 1 by controlling the operation of various controlled objects such as spark plugs 10a and 10b and fuel injector 13, based on output signals from various sensors such as water temperature sensor 101, crank angle sensor 102, intake pressure sensor 103, throttle opening sensor 104, O2 sensor 110, and vehicle speed sensor 120, as well as by reading the necessary control and processing programs and control and processing data from memory and executing the control and processing programs.

[0026] Specifically, the ECU 150 includes an ignition control unit 151 that controls the ignition operation of spark plugs 10a and 10b by controlling the supply of power to ignition coils L1 and L2, a fuel injection control unit 152 that controls the fuel injection operation of fuel injector 13 by controlling the supply of power to fuel injector 13, and an abnormality determination unit 153 that determines whether or not there is an ignition abnormality in spark plugs 10a and 10b. In the figure, the ignition control unit 151, fuel injection control unit 152, and abnormality determination unit 153 are shown as functional blocks when executing the control and processing program.

[0027] The ignition control unit 151 refers to the data of the basic ignition timing map stored in memory and calculates the basic ignition timing for each of the spark plugs 10a and 10b according to the engine speed (engine rotational speed) calculated based on the output signal from the crank angle sensor 102 and the throttle opening calculated based on the output signal from the throttle opening sensor 104. It also refers to the data of the corrected ignition timing map stored in memory and calculates the corrected ignition timing for each of the spark plugs 10a and 10b according to the engine temperature calculated based on the output signal from the water temperature sensor 101. When the ignition control unit 151 calculates the ignition timing from the basic ignition timing and corrected ignition timing for each of the spark plugs 10a and 10b, it calculates the ignition timing of spark plug 10a as being advanced compared to the ignition timing of spark plug 10b. The ignition control unit 151 then performs ignition control to ignite spark plugs 10a and 10b by outputting drive signals to ignition coils L1 and L2, respectively, and energizing them in accordance with the ignition timings calculated from the basic ignition timing and corrected ignition timing for each spark plug 10a and 10b, such that the ignition timing of spark plug 10a is advanced compared to the ignition timing of spark plug 10b. The ignition timings calculated from the basic ignition timing and corrected ignition timing for spark plugs 10a and 10b in this manner are used as the normal ignition timings when the ignition capabilities of both spark plugs 10a and 10b are normal.

[0028] The fuel injection control unit 152 refers to the data of the basic fuel injection amount map stored in memory and calculates a basic fuel injection amount corresponding to the engine speed calculated based on the output signal from the crank angle sensor 102 and the throttle opening calculated based on the output signal from the throttle opening sensor 104. It also refers to the data of the corrected fuel injection amount map stored in memory and calculates a corrected fuel injection amount corresponding to the engine temperature calculated based on the output signal from the water temperature sensor 101. Then, at a predetermined fuel injection timing, the fuel injection control unit 152 outputs a drive signal to the fuel injection valve 13 to energize it and open it so that the fuel injection amount calculated from the basic fuel injection amount and the corrected fuel injection amount is injected into the intake passage 11a.

[0029] The abnormality determination unit 153 detects abnormalities in the electrical system from the ECU 150 through the ignition coil L1 to the spark plug 10a, thereby determining whether there is an abnormality in the ignition capability of the spark plug 10a (ignition abnormality). For this purpose, from a practical standpoint, it is preferable for the abnormality determination unit 153 to detect whether an abnormality such as a break in the wire or a short circuit has occurred in the primary voltage side electrical system, which has a lower voltage than the secondary voltage side electrical system of the ignition coil L1. For example, the abnormality determination unit 153 detects the voltage or current of the electrical wiring W1 that electrically connects the output terminals of the drive circuits for the spark plugs 10a (not shown) of the ECU 150 and the input terminals of the primary coils (not shown) of the ignition coil L1. If the detected voltage or current falls within a predetermined range indicating an abnormality (typically a range close to zero or less), the unit determines that an abnormality such as a break in the wire or a short circuit has occurred in the primary voltage side electrical system of the ignition coil L1, and determines that there is an abnormality in the ignition capability of the spark plug 10a. Furthermore, an abnormality in the ignition capability of the spark plug 10a means not only that the spark plug 10a does not ignite at all even when a drive signal for energizing the spark plug 10a is output from the ECU 150 via the ignition coil L1, but also that even if the spark plug 10a ignites to some extent, the ignition state is not sufficient to ignite the fuel-air mixture. In addition, the abnormality determination unit 153 detects an abnormality in the energization of the electrical system from the ECU 150 through the ignition coil L2 to the spark plug 10b, and determines whether or not there is an abnormality in the ignition capability (ignition abnormality) of the spark plug 10b. In such cases, similar to determining whether there is an abnormality in the ignition capability (ignition abnormality) of the spark plug 10b, the abnormality determination unit 153 detects the voltage or current of the electrical wiring W2 that electrically connects the output terminals of the drive circuits for the spark plugs 10b (not shown) of the ECU 150 and the input terminals of the primary coils (not shown) of the ignition coils L2. If the detected voltage or current falls within a predetermined range indicating an abnormality (typically a range close to zero or less), the unit determines that an electrical abnormality such as a break in the wire or a short circuit has occurred in the electrical system on the primary voltage side of the ignition coil L2, and determines that there is an abnormality in the ignition capability of the spark plug 10b.In this context, an abnormality in the ignition capability of the spark plug 10b means not only that the spark plug 10b does not ignite at all even when a drive signal for energizing the spark plug 10b is output from the ECU 150 via the ignition coil L2, but also that even if the spark plug 10b ignites to some extent, the ignition state is not sufficient to ignite the fuel-air mixture.

[0030] In this configuration, where the ignition timing of spark plug 10a is set to advance more than the ignition timing of spark plug 10b, if the abnormality determination unit 153 determines that there is no abnormality in the ignition capability of spark plug 10a and that it is normal, but determines that an abnormality has occurred in the ignition capability of spark plug 10b, the ignition control unit 151 sets the ignition timing of spark plug 10a to a retarded ignition timing compared to the ignition timing of spark plug 10a when both spark plugs 10a and 10b are determined to be normal. By retarding the ignition timing of spark plug 10a in this way, if there is an ignition abnormality in spark plug 10b, which has an ignition timing set to be retarded more than that of spark plug 10a, it becomes possible to bring the overall ignition state of one cylinder 2a of the engine 1 closer to the originally intended state, and stabilize the combustion of the air-fuel mixture in the combustion chamber 9 of that cylinder 2a. Furthermore, from the viewpoint of appropriately setting the amount of retardation for retarding the ignition timing of spark plug 10a, it is preferable to set the amount of retardation according to the engine speed and throttle opening, similar to the basic ignition timing. Also, from the viewpoint of bringing the overall ignition state closer to the originally intended state, it is preferable to set the ignition timing after retardation of spark plug 10a within the range between the original ignition timing without retardation at spark plug 10a and the original ignition timing without abnormalities at spark plug 10b.

[0031] Furthermore, it is conceivable that the abnormality detection unit 153 may determine that there is no abnormality in the ignition capability of spark plug 10b and that it is normal, but that an abnormality has occurred in the ignition capability of spark plug 10a. In such a case, the ignition control unit 151 may set the ignition timing of spark plug 10b to an advanced ignition timing compared to the ignition timing of spark plug 10a when both spark plugs 10a and 10b are determined to be normal. By advancing the ignition timing of spark plug 10b in this way, if there is an ignition abnormality in spark plug 10a, which is set to an ignition timing advanced compared to the ignition timing of spark plug 10b, it becomes possible to bring the overall ignition state of one cylinder 2a of the engine 1 closer to the originally intended state, and stabilize the combustion of the air-fuel mixture in the combustion chamber 9 of that cylinder 2a. Furthermore, from the viewpoint of appropriately setting the magnitude of the ignition timing advance of the spark plug 10b, it is preferable to set the magnitude of the advance according to the engine speed and throttle opening, similar to the basic ignition timing. Also, from the viewpoint of bringing the overall ignition state closer to the originally intended state, it is preferable to set the ignition timing after the advance of the spark plug 10b within the range between the original ignition timing without advance at the spark plug 10b and the original ignition timing without abnormalities at the spark plug 10a. In addition, from the viewpoint of suppressing the occurrence of knocking in the engine 1 and stabilizing the combustion itself, it is preferable to set the degree of advance to decrease as the throttle opening increases. On the other hand, from the viewpoint of protecting the catalytic converter 109, which is a three-way catalytic converter of the engine 1, it is preferable to set the degree of advance to increase as the throttle opening TH increases.

[0032] Furthermore, when the abnormality determination unit 153 determines that there is no abnormality in the ignition capacity of spark plug 10a and that it is normal, but determines that an abnormality has occurred in the ignition capacity of spark plug 10b, in order to reliably adjust the ignition state to be closer to the originally intended state, it is preferable for the ignition control unit 151 to use the correction coefficient map shown in Figure 2(a), and such a correction coefficient map is pre-stored as data in memory so as to be applied according to the spark plug 10a for which no abnormality has occurred in its ignition capacity. Similarly, when the abnormality determination unit 153 determines that there is no abnormality in the ignition capacity of spark plug 10b and that it is normal, but determines that an abnormality has occurred in the ignition capacity of spark plug 10a, in order to reliably adjust the ignition state to be closer to the originally intended state, it is preferable for the ignition control unit 151 to use the correction coefficient map shown in Figure 2(b), and such a correction coefficient map is pre-stored as data in memory so as to be applied according to the spark plug 10b for which no abnormality has occurred in its ignition capacity.

[0033] First, as an example, if the ignition capability of spark plug 10a as the first spark plug is determined to be normal with no abnormalities observed, but the ignition capability of spark plug 10b as the second spark plug is determined to be abnormal, the correction coefficient map shown in Figure 2(a) will be used. The correction coefficient map shown in Figure 2(a) is a map that has values ​​of correction coefficients XMAL111 to XMAL1nm defined according to the engine speed NE from NE1 to NEm (m is a natural number greater than 1) and the throttle opening TH from TH1 to THn (n is a natural number greater than 1), in order to accurately retard the ignition timing of spark plug 10a using such a correction coefficient map, similar to when the basic ignition timing is calculated according to the engine speed and throttle opening, and the data is stored in memory. Here, if we let THa (where a is a natural number greater than 1 and less than n) be the throttle opening corresponding to the intermediate load of engine 1, then the values ​​of the correction coefficients XMAL1a1 to XMAL1am will be the values ​​of the correction coefficients at the intermediate load, corresponding to each engine speed NE1 to NEm. The low-load side of engine 1 is the side of throttle opening TH that is smaller than throttle opening THa (smaller than THa and greater than or equal to TH1), and the high-load side of engine 1 is the side of throttle opening TH that is larger than throttle opening THa (greater than THa and less than or equal to THn). Furthermore, the values ​​of these correction coefficients XMAL111 to XMAL1nm are correction coefficients for retarding the rotation angle of engine 1, and are therefore typically set to positive values ​​less than 1.

[0034] If the ignition capability of spark plug 10a is determined to be normal and without any abnormalities, but the ignition capability of spark plug 10b is determined to be abnormal, the ignition control unit 151 refers to the data of the correction coefficient map stored in memory as shown in Figure 2(a) and calculates a correction coefficient corresponding to the engine speed calculated based on the output signal from the crank angle sensor 102 and the throttle opening calculated based on the output signal from the throttle opening sensor 104. By multiplying this correction coefficient by the normal ignition timing (ignition timing calculated from the basic ignition timing and the corrected ignition timing) when the ignition capabilities of both spark plugs 10a and 10b are normal, the ignition control unit 151 sets the ignition timing to be retarded compared to the ignition timing when both spark plugs 10a and 10b are determined to be normal.

[0035] As an example, if the ignition capability of spark plug 10b as the second spark plug is determined to be normal with no abnormalities, but the ignition capability of spark plug 10a as the first spark plug is determined to be abnormal, the correction coefficient map shown in Figure 2(b) will be used. The correction coefficient map shown in Figure 2(b) is a map that has values ​​of correction coefficients XMAL211 to XMAL2nm defined according to the engine speed NE from NE1 to NEm (m is a natural number greater than 1) and the throttle opening TH from TH1 to THn (n is a natural number greater than 1), in order to accurately advance the ignition timing of spark plug 10b using such a correction coefficient map, similar to when the basic ignition timing is calculated according to the engine speed and throttle opening, and the data is stored in memory. Here, if we let THa be the throttle opening corresponding to the intermediate load of engine 1, then the values ​​of the correction coefficients XMAL2a1 to XMAL2am correspond to the respective engine speeds NE1 to NEm, and the values ​​of the correction coefficients at the intermediate load are as follows: the low load side of engine 1 is the side of throttle opening TH that is smaller than the throttle opening THa (smaller than THa and greater than or equal to TH1), and the high load side of engine 1 is the side of throttle opening TH that is larger than the throttle opening THa (greater than THa and less than or equal to THn). Furthermore, the values ​​of these correction coefficients XMAL211 to XMAL2nm are the values ​​of the correction coefficients for advance ignition timing to increase the rotation angle of engine 1, and are therefore typically set to values ​​of 1 or greater. In addition, from the viewpoint of suppressing the occurrence of knocking in engine 1 and stabilizing the combustion itself, it is preferable that the values ​​of the correction coefficients be set to gradually approach 1 and decrease so that the degree of advance ignition timing decreases as the throttle opening TH increases from TH1 to THm. On the other hand, from the viewpoint of protecting the catalytic converter 109, which is a three-way catalytic converter of engine 1, it is preferable that the value of the correction coefficient be set to gradually increase from 1 so that the degree of ignition timing advance increases as the throttle opening TH increases from TH1 to THm.

[0036] If the ignition capability of spark plug 10b is determined to be normal and without any abnormalities, but the ignition capability of spark plug 10a is determined to be abnormal, the ignition control unit 151 refers to the correction coefficient map data stored in memory as shown in Figure 2(b) and calculates a correction coefficient corresponding to the engine speed calculated based on the output signal from the crank angle sensor 102 and the throttle opening calculated based on the output signal from the throttle opening sensor 104. By multiplying this correction coefficient by the normal ignition timing (ignition timing calculated from the basic ignition timing and the corrected ignition timing) when the ignition capabilities of both spark plugs 10a and 10b are normal, the ignition control unit 151 advances the ignition timing compared to the ignition timing when both spark plugs 10a and 10b are determined to be normal.

[0037] The engine control device 50, having the configuration described above, performs a correction coefficient calculation process including the abnormality determination process shown below. This process is performed when it is determined that the ignition capability of spark plug 10a is normal and no abnormalities are found, but an abnormality has occurred in the ignition capability of spark plug 10b, and also when it is determined that the ignition capability of spark plug 10b is normal and no abnormalities are found, but an abnormality has occurred in the ignition capability of spark plug 10a. In these cases, the engine control device 50 refers to the data of the correction coefficient map stored in memory, as shown in Figures 2(a) and (b), and calculates a correction coefficient corresponding to the engine speed calculated based on the output signal from the crank angle sensor 102 and the throttle opening calculated based on the output signal from the throttle opening sensor 104. The operation of the engine control device 50 when performing the correction coefficient calculation process will be explained below with reference to Figure 3.

[0038] <Calculation process for correction coefficient> Figure 3 is a flowchart showing an example of the correction coefficient calculation process of the engine control device in this embodiment.

[0039] The flowchart shown in Figure 3 begins when the ignition switch (not shown) changes from the off state to the on state and the ECU 150 starts up, and the correction coefficient calculation process proceeds to step S1. This correction coefficient calculation process is repeatedly executed at predetermined control cycles while the ECU 150 is running, by reading the necessary control / processing program and control / processing data from memory. For convenience, spark plug 10a will be referred to as the first spark plug and spark plug 10b as the second spark plug in this explanation.

[0040] In step S1, the abnormality determination unit 153 determines whether or not an ignition abnormality has occurred in the spark plug 10a. Specifically, the abnormality determination unit 153 detects the voltage applied to the electrical wiring W1 or the current flowing through the electrical wiring W1. If the detected voltage or current falls within a predetermined range indicating an abnormality, the unit determines that an electrical abnormality such as a break in the wire or a short circuit has occurred in the primary voltage side of the ignition coil L1, and determines that an abnormality has occurred in the ignition capability of the spark plug 10a. If the determination results in an ignition abnormality in the spark plug 10a, the abnormality determination unit 153 proceeds to step S2 to calculate the correction coefficient. On the other hand, if the determination results in no ignition abnormality in the spark plug 10a, the abnormality determination unit 153 proceeds to step S3 to calculate the correction coefficient. The data for the predetermined range indicating such abnormalities was referenced from data stored in memory.

[0041] In step S2, the abnormality determination unit 153 determines whether or not an ignition abnormality has occurred in the spark plug 10b. Specifically, the abnormality determination unit 153 detects the voltage applied to the electrical wiring W2 or the current flowing through the electrical wiring W2. If the detected voltage or current falls within a predetermined range indicating an abnormality, the unit determines that an electrical abnormality such as a break in the wire or a short circuit has occurred in the electrical system on the primary voltage side of the ignition coil L2, and determines that an abnormality has occurred in the ignition capability of the spark plug 10b. If the determination results in an ignition abnormality in the spark plug 10b, the abnormality determination unit 153 proceeds to step S4 to calculate the correction coefficient. On the other hand, if the determination results in no electrical abnormality occurring in the spark plug 10b, the abnormality determination unit 153 proceeds to step S5 to calculate the correction coefficient. The data for the predetermined range indicating such abnormalities was referenced from data stored in memory.

[0042] In step S3, the abnormality determination unit 153 determines whether or not an ignition abnormality has occurred in the spark plug 10b. Specifically, the abnormality determination unit 153 detects the voltage applied to the electrical wiring W2 or the current flowing through the electrical wiring W2. If the detected voltage or current falls within a predetermined range indicating an abnormality, the unit determines that an electrical abnormality such as a break in the wire or a short circuit has occurred in the electrical system on the primary voltage side of the ignition coil L2, and determines that an abnormality has occurred in the ignition capability of the spark plug 10b. If the determination results in an ignition abnormality in the spark plug 10b, the abnormality determination unit 153 proceeds to step S6 to calculate the correction coefficient. On the other hand, if the determination results in no electrical abnormality occurring in the spark plug 10b, the abnormality determination unit 153 proceeds to step S7 to calculate the correction coefficient. The data for the predetermined range indicating such abnormalities was referenced from data stored in memory.

[0043] In step S4, since an abnormality occurs in both spark plugs 10a and 10b, the ignition control unit 151 stops the supply of power to both spark plugs 10a and 10b via drive signals to forcibly stop their ignition operation, and the fuel injection control unit 152 stops the supply of power to the fuel injection valve 13 via drive signals to forcibly stop its fuel injection operation, thereby forcibly stopping the operation of the engine 1. With this, the process of step S4 is completed, and this series of correction coefficient calculation processes is finished.

[0044] In step S5, it is determined that the ignition capability of spark plug 10b is normal and no abnormalities were found, but an abnormality occurred in the ignition capability of spark plug 10a. In this case, the ignition control unit 151 calculates a correction coefficient. Specifically, the ignition control unit 151 refers to the correction coefficient map data stored in memory as shown in Figure 2(a) and calculates a correction coefficient value corresponding to the engine speed calculated based on the output signal from the crank angle sensor 102 and the throttle opening calculated based on the output signal from the throttle opening sensor 104. With this, the process of step S5 is completed, and this series of correction coefficient calculation processes is finished. Furthermore, the ignition control unit 151 multiplies the correction coefficient of the value calculated in this way by the normal ignition timing (the ignition timing calculated from the basic ignition timing and the corrected ignition timing) when both spark plugs 10a and 10b have normal ignition capabilities. As a result, the ignition control unit 151 sets an ignition timing that is more advanced than the ignition timing when it is determined that both spark plugs 10a and 10b are normal.

[0045] In step S6, it is determined that the ignition capability of spark plug 10b is normal and no abnormalities were found, but an abnormality occurred in the ignition capability of spark plug 10a. In this case, the ignition control unit 151 calculates a correction coefficient. Specifically, the ignition control unit 151 refers to the correction coefficient map data stored in memory as shown in Figure 2(b) and calculates a correction coefficient value corresponding to the engine speed calculated based on the output signal from the crank angle sensor 102 and the throttle opening calculated based on the output signal from the throttle opening sensor 104. With this, the process in step S5 is completed, and this series of correction coefficient calculation processes is finished. Furthermore, the ignition control unit 151 multiplies the correction coefficient of the value calculated in this way by the normal ignition timing (the ignition timing calculated from the basic ignition timing and the corrected ignition timing) when both spark plugs 10a and 10b have normal ignition capabilities. As a result, the ignition control unit 151 sets an ignition timing that is retarded compared to the ignition timing when it determines that both spark plugs 10a and 10b are normal.

[0046] In step S7, assuming that no abnormalities have occurred in either spark plug 10a or 10b, the ignition control unit 151 does not calculate the correction coefficient in cases where it determines that the ignition capacity of spark plug 10b is normal and no abnormalities have been found, but it determines that an abnormality has occurred in the ignition capacity of spark plug 10a, or where it determines that the ignition capacity of spark plug 10b is normal and no abnormalities have been found, but it determines that an abnormality has occurred in the ignition capacity of spark plug 10a. With this, the process of step S7 is completed, and this series of correction coefficient calculation processes is finished. In such cases, the ignition control unit 151 will calculate the normal ignition timing (the ignition timing calculated from the basic ignition timing and the corrected ignition timing) when the ignition capacity of both spark plugs 10a and 10b is normal.

[0047] In the internal combustion engine control device 50 of this embodiment, the ignition control unit 151 sets the ignition timing of the first spark plug 10a to be retarded compared to the ignition timing of the second spark plug 10b when both the first spark plug 10a and the second spark plug 10b are in a normal state, and to retard the ignition timing of the first spark plug 10a when the first spark plug 10a is in a normal state and the second spark plug 10b is in an abnormal state. In this way, if an abnormality occurs only in the retarded spark plug 10b of the two spark plugs 10a and 10b provided in the internal combustion engine 1, the ignition timing of the advanced spark plug 10a, which is not abnormal, can be appropriately set to stabilize the combustion of the internal combustion engine 1.

[0048] Furthermore, in the internal combustion engine control device 50 of this embodiment, the ignition control unit 151 sets the ignition timing of the first spark plug 10a to retard according to the rotational speed of the internal combustion engine 1 and the throttle opening of the internal combustion engine 1 when the first spark plug 10a is in a normal state and the second spark plug 10b is in an abnormal state. This allows the ignition timing of the advancing spark plug 10a, which is not abnormal, to be set more appropriately when an abnormality occurs only in the retarding spark plug 10b of the two spark plugs 10a and 10b provided in the internal combustion engine 1, thereby further stabilizing the combustion of the internal combustion engine 1.

[0049] 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 is of course possible to modify them as appropriate without departing from the spirit of the invention, such as by appropriately substituting the components with those that produce equivalent effects. [Industrial applicability]

[0050] As described above, the present invention provides an internal combustion engine control device that can stabilize the combustion of an internal combustion engine by appropriately setting the ignition timing of the advancing spark plug, which is not malfunctioning, when a malfunction occurs only in the retarding spark plug of the two spark plugs provided in the internal combustion engine. Due to its general-purpose and universal nature, it is expected to be widely applicable to internal combustion engine control devices for motorcycles. [Explanation of Symbols]

[0051] 1…Engine (internal combustion engine) 2…Cylinder block 2a…Cylinder 4…Piston 5…Connecting rod 6…Crankshaft 7… Relacta 7a…teeth part 8…Cylinder head 9… Combustion chamber 10a, 10b…Spark plug 11…Intake pipe 11a... Intake passage 12…Intake valve 13…Fuel injector 14…Throttle valve 15… Exhaust pipe 15a... Exhaust passage 16… Exhaust valve 50…Engine control device (internal combustion engine control device) 100... Engine control device 101...Water temperature sensor 102... Crank angle sensor 103... Intake pressure sensor 104... Throttle position sensor 109... Catalyst 110...O2 sensor 120... Vehicle speed sensor 150…ECU 151... Ignition control unit 152…Fuel injection control unit (fuel supply control unit) 153...Abnormality determination section L1, L2... Ignition coils W1, W2... Electrical wiring

Claims

[Claim 1] An internal combustion engine control device comprising: an ignition control unit that controls the ignition operation by a first spark plug and a second spark plug provided for one cylinder of an internal combustion engine; and a fuel supply control unit that controls the fuel supply operation to the internal combustion engine, wherein the first ignition timing of the first spark plug is set to an ignition timing that is advanced compared to the second ignition timing of the second spark plug, The ignition control unit is configured to retard the first ignition timing when the first spark plug is in a normal state and the second spark plug is in an abnormal state, compared to the first ignition timing when both the first and second spark plugs are in a normal state. The first ignition timing after retarding the first spark plug when the first spark plug is in the normal state and the second spark plug is in the abnormal state is set within the range between the first ignition timing in the normal state for the first spark plug and the second ignition timing in the normal state for the second spark plug, and the ignition control unit sets the first ignition timing when the first spark plug is in the normal state and the second spark plug is in the abnormal state to retard it according to the rotational speed and throttle opening of the internal combustion engine by multiplying the first ignition timing, which is calculated according to the rotational speed and throttle opening of the internal combustion engine using an ignition timing map for when both the first and second spark plugs are in the normal state, by a correction coefficient calculated according to the rotational speed and throttle opening using a correction coefficient map for when the first spark plug is in the normal state and the second spark plug is in the abnormal state.

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