Controller

Abstract

To provide a controller capable of suppressing generation of combustion failure such as slow combustion or accidental fire.SOLUTION: The present invention is a controller for an internal combustion engine. When combustion failure occurs in the internal combustion engine due to an insufficient intake amount, the controller increases the intake amount of the internal combustion engine and retards the ignition timing of the internal combustion engine.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] A known example of a conventional invention relating to a control device for an internal combustion engine is a control device for an engine-driven generator described in Patent Document 1. The purpose of this engine-driven generator is to enable control of the engine ignition timing to MBT (Minimum Spark Advance for Best Torque) without being affected by mass production variations and the like. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 6-241150 Summary of the Invention [Problem to be solved by the invention]

[0004] In the field of control devices for engine-driven generators such as those described above, there is a demand for suppressing the occurrence of poor combustion such as slow combustion and misfires.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a control device that can suppress the occurrence of poor combustion such as slow combustion and misfires. [Means for solving the problem]

[0006] A first aspect of the present invention is A control device for an internal combustion engine, When poor combustion occurs in the internal combustion engine due to an insufficient amount of intake air, the control device increases the amount of intake air of the internal combustion engine and retards the ignition timing of the internal combustion engine. It is a control device.

[0007] A second aspect of the present invention is the control device determines whether or not the poor combustion has occurred based on a fluctuation range of the rotation speed of the internal combustion engine. 1 is a control device according to a first aspect.

[0008] A third aspect of the present invention is the control device determines an upper limit value of the retard amount of the ignition timing based on an intake air amount of the internal combustion engine. 2 is a control device according to a second aspect.

[0009] A fourth aspect of the present invention is the control device determines the increase amount of the intake air amount and the derivative value of the intake air amount so that the increase amount of the intake air amount and / or the derivative value of the intake air amount become larger as the fluctuation range becomes smaller. The control device according to the second or third aspect.

[0010] A fifth aspect of the present invention is When the control device is increasing the intake amount of the internal combustion engine due to a shortage of the intake amount, the control device retards the ignition timing of the internal combustion engine from MBT (Minimum Spark Advance for Best Torque). The control device is according to any one of the first to fourth aspects.

[0011] A sixth aspect of the present invention is a vehicle comprising the internal combustion engine, a motor, a generator, and one or more wheels; the generator is operated by the internal combustion engine to generate electric power; the motor generates power transmitted to the one or more wheels of the vehicle using the electric power generated by the generator; the internal combustion engine does not generate power that is transmitted to the one or more wheels; The control device is according to any one of the first to fifth aspects. [Effects of the Invention]

[0012] According to the present invention, the occurrence of poor combustion such as slow combustion and misfire can be suppressed. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram of a vehicle 10 . [Figure 2] FIG. 2 is a schematic diagram of a vehicle 10 including an internal combustion engine 26 . [Figure 3] FIG. 3 is a graph showing the relationship between the combustion chamber volume and the compression end temperature. [Figure 4] FIG. 4 is a graph showing the time variations of the rotation speed R, the opening φ, the ignition timing T, the intake amount F, and the intake pressure P. [Figure 5] FIG. 5 is a graph showing the change in rotation speed R over time. [Figure 6] FIG. 6 is a graph showing the change in rotation speed R over time. [Figure 7] FIG. 7 is the first table. [Figure 8] FIG. 8 is the second table. [Figure 9] FIG. 9 is the third table. [Figure 10] FIG. 10 is a flowchart showing the process executed by the control device 100. DETAILED DESCRIPTION OF THE INVENTION

[0014] (Embodiment) [Vehicle structure] The structure of a vehicle 10 equipped with a control device 100 according to one embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a schematic diagram of the vehicle 10. Fig. 2 is a schematic diagram of the vehicle 10 including an internal combustion engine 26.

[0015] The vehicle 10 is, for example, a four-wheeled automobile. The vehicle 10 is a hybrid vehicle. In this embodiment, the vehicle 10 is a series hybrid vehicle. As shown in Fig. 1, the vehicle 10 includes an internal combustion engine 26, a battery 36, a generator 50, a motor 52, an inverter 54, a power transmission device 56, a left front wheel 58L, and a right front wheel 58R (one or more wheels).

[0016] The internal combustion engine 26 generates power using gasoline as fuel. The internal combustion engine 26 generates power to operate the generator 50, which will be described later. The internal combustion engine 26 does not generate power that is transmitted to the left front wheel 58L and the right front wheel 58R (one or more wheels). The internal combustion engine 26 is a four-stroke engine. The internal combustion engine 26 is an engine that has one or more cylinders, but generally an engine that has multiple cylinders. When the internal combustion engine 26 is an engine that has multiple cylinders, the multiple cylinders may be arranged in a single row, two rows, or four rows.

[0017] The generator 50 is connected to the internal combustion engine 26. The generator 50 generates electric power by being operated by the internal combustion engine 26. The generator 50 is, for example, an AC generator.

[0018] The battery 36 stores the power generated by the generator 50. The battery 36 is a secondary battery that can be charged and discharged. The battery 36 is, for example, a lithium-ion battery or an all-solid-state battery.

[0019] The motor 52 generates power using the power generated by the generator 50, which is transmitted to a left front wheel 58L and a right front wheel 58R (one or more wheels) of the vehicle 10. In this embodiment, the motor 52 generates power to run the vehicle 10 using the power stored in the battery 36. The power stored in the battery 36 is power generated by the generator 50. However, the battery 36 may store power generated when the vehicle 10 decelerates, in addition to the power generated by the generator 50. The motor 52 is, for example, an AC motor.

[0020] The inverter 54 controls the motor 52. In this embodiment, the inverter 54 converts the AC current generated by the generator 50 into DC current and supplies the DC current to the battery 36. As a result, the battery 36 is charged with the power generated by the generator 50. The inverter 54 also converts the DC current generated by the battery 36 into AC current and supplies the AC current to the motor 52. The motor 52 operates on the AC current supplied from the inverter 54.

[0021] The power generated by the motor 52 is transmitted to the power transmission device 56. The power transmission device 56 transmits the power generated by the motor 52 to a left front wheel 58L and a right front wheel 58R. Such a power transmission device 56 is, for example, a reducer and a differential.

[0022] 2, the vehicle 10 further includes an injector 31, an electronic throttle 32, a crank angle sensor 38, a throttle position sensor 42, a control device 100, a storage device 102, an intake path R1, and an exhaust path R2 in addition to the internal combustion engine 26. The internal combustion engine 26 also includes a piston 27, a crankshaft 29, and a spark plug 30.

[0023] The intake path R1 is a path through which air passes. An injector 31 is provided in the intake path R1. The injector 31 injects fuel. This causes an air-fuel mixture to be formed in the intake path R1. The intake path R1 is connected to an intake port of the internal combustion engine 26. Therefore, the air-fuel mixture flows from the intake path R1 through the intake port into the combustion chamber of the internal combustion engine 26.

[0024] In the internal combustion engine 26, the combustion of the air-fuel mixture causes the piston 27 to move up and down. The up and down movement of the piston 27 is converted into the rotation of the crankshaft 29. As a result, the internal combustion engine 26 generates power. At this time, the internal combustion engine 26 generates exhaust gas.

[0025] The exhaust path R2 is connected to an exhaust port of the internal combustion engine 26. The exhaust path R2 is a path through which the exhaust gas flowing out from the internal combustion engine 26 passes.

[0026] The electronic throttle 32 is a valve that adjusts the amount of air passing through the intake path R1 (hereinafter referred to as the intake air amount). The electronic throttle 32 is provided in the intake path R1. The electronic throttle 32 opens and closes the intake path R1 under the control of a control device 100, which will be described later.

[0027] The crank angle sensor 38 generates a crank angle signal b that indicates the angle of the crankshaft 29 of the internal combustion engine 26. The crank angle signal b is output to the control device 100. The control device 100 can calculate the rotation speed R of the internal combustion engine 26 based on the crank angle signal b.

[0028] The control device 100 is an ECU (Engine Control Unit). The control device 100 controls an internal combustion engine 26, an ignition plug 30, an injector 31, and an electronic throttle 32. The storage device 102 is a combination of a ROM (Read Only Memory) and a RAM (Random Access Memory). The storage device 102 stores programs executed by the control device 100.

[0029] The control device 100 receives a vehicle speed signal a, a crank angle signal b, an accelerator opening signal c, an intake air temperature / intake pressure signal d, a cooling water temperature signal e, and an atmospheric pressure signal f.

[0030] The vehicle speed signal a is output from a vehicle speed sensor that detects the actual vehicle speed of the vehicle 10. The accelerator opening signal c is output from a sensor that detects the depression amount of the accelerator pedal or the opening degree of the electronic throttle 32 as the accelerator opening degree (in other words, the required engine load factor). The intake air temperature / intake pressure signal d is output from a temperature / pressure sensor that detects the intake air temperature and intake pressure in the intake path R1. The coolant temperature signal e is output from a water temperature sensor that detects the coolant temperature, which indicates the temperature of the internal combustion engine 26. The atmospheric pressure signal f is output from an atmospheric pressure sensor that detects the atmospheric pressure.

[0031] The control device 100 calculates a target rotation speed Rt of the internal combustion engine 26 and estimates a base intake air amount Fb to be filled into the cylinders of the internal combustion engine 26 based on a vehicle speed signal a, a crank angle signal b, an accelerator opening signal c, an intake air temperature / intake air pressure signal d, a coolant temperature signal e, and an atmospheric pressure signal f. Then, the control device 100 determines a fuel injection amount, a fuel injection timing, a fuel injection pressure, and a base ignition timing Tb based on the target rotation speed Rt and the base intake air amount Fb of the internal combustion engine 26. Then, the control device 100 generates an ignition signal h, a fuel injection signal i, and an opening control signal j based on the fuel injection amount, the fuel injection timing, the fuel injection pressure, and the base ignition timing Tb.

[0032] The ignition signal h is output to an igniter. The igniter generates a spark in the spark plug 30 based on the ignition signal h. The fuel injection signal i is output to the injector 31. The injector 31 injects fuel based on the fuel injection signal i. The opening control signal j is output to the electronic throttle 32. The electronic throttle 32 opens and closes the throttle valve based on the opening control signal j.

[0033] [Operation of the control device 100] Next, the operation of the control device 100 will be described with reference to the drawings. Figure 3 is a graph showing the relationship between the combustion chamber volume and the compression end temperature.

[0034] The vehicle 10 is a series hybrid vehicle. In a series hybrid vehicle, the power generated by the internal combustion engine 26 is transmitted to the generator 50, and is not transmitted to the left front wheel 58L and the right front wheel 58R. In such a series hybrid vehicle, the spark plug 30 is ignited in MBT when the internal combustion engine 26 is in a light load range in order to improve fuel economy.

[0035] However, if the spark plug 30 ignites at the MBT, poor combustion, such as slow combustion or misfire, is likely to occur, as explained below. In a vehicle that runs solely on power generated by an internal combustion engine, the ignition timing of the spark plug is retarded from the MBT in the light load range. If the ignition timing is retarded from the MBT, the output of the internal combustion engine decreases. Therefore, in such internal combustion engines, the amount of fuel injected and the amount of intake air are increased.

[0036] On the other hand, in a series hybrid vehicle, as described above, the spark plug 30 is ignited at MBT when the internal combustion engine 26 is in a light load range in order to improve fuel economy. Therefore, the amount of intake air in a series hybrid vehicle is less than the amount of intake air in a vehicle that runs solely on power generated by the internal combustion engine. Therefore, the temperature of the air-fuel mixture in the combustion chamber at top dead center of compression (compression end temperature) in a series hybrid vehicle is lower than the compression end temperature in a vehicle that runs solely on power generated by the internal combustion engine. Therefore, ignition at MBT in a series hybrid vehicle is prone to poor combustion, such as slow combustion and misfires.

[0037] Incidentally, it has been proposed to lower the effective compression ratio of the internal combustion engine 26 in order to improve fuel economy. Specifically, a variable valve timing mechanism is provided in the internal combustion engine 26. The intake valve is then closed after the bottom dead center of the compression stroke. This lowers the effective compression ratio and reduces pumping loss. As a result, the fuel economy of the internal combustion engine 26 improves.

[0038] However, when the effective compression ratio is lowered, the amount of intake air into the internal combustion engine 26 is reduced. As a result, the temperature of the air-fuel mixture in the combustion chamber at the top dead center of compression (compression end temperature) becomes even lower. Therefore, in the internal combustion engine 26 of a series hybrid vehicle, when the effective compression ratio is lowered, poor combustion such as slow combustion and misfires becomes even more likely to occur.

[0039] In a typical internal combustion engine, poor combustion, such as slow combustion or misfire, occurs when a spark plug is ignited by MBT in the light load range. However, as shown in FIG. 3, the volume of the combustion chamber of an internal combustion engine varies due to manufacturing errors. When the volume of the combustion chamber is larger than the specified value, the compression ratio decreases, resulting in a decrease in the compression end temperature. When the volume of the combustion chamber is smaller than the specified value, the compression ratio increases, resulting in a rise in the compression end temperature. Furthermore, when the volume of the combustion chamber is at the upper limit of the variation, the compression end temperature becomes too low, resulting in poor combustion. Because of this variation in the volume of the combustion chamber, it is difficult to suppress poor combustion through the design of the internal combustion engine. Therefore, the inventors of the present application came up with the control device 100 described below.

[0040] Here, FIG. 4 is a graph showing the time variations of the rotation speed R, opening φ, ignition timing T, intake air amount F, and intake pressure P. FIGS. 5 and 6 are graphs showing the time variations of the rotation speed R. In FIG. 5, no poor combustion occurs. In FIG. 6, poor combustion occurs. FIG. 7 is the first table. FIG. 8 is the second table. FIG. 9 is the third table.

[0041] From time t0 to t1 in Fig. 4, poor combustion due to an insufficient amount of intake air occurs in the internal combustion engine 26. On the other hand, from time t4 onwards in Fig. 4, poor combustion due to an insufficient amount of intake air does not occur in the internal combustion engine 26. As shown in the enlarged views A and B in Fig. 4, the fluctuation width w1 of the rotation speed R when poor combustion due to an insufficient amount of intake air occurs in the internal combustion engine 26 is smaller than the fluctuation width w2 of the rotation speed R when poor combustion due to an insufficient amount of intake air does not occur in the internal combustion engine 26. The reason for this will be explained below.

[0042] As shown in FIG. 5, when the internal combustion engine 26 is not experiencing poor combustion due to an insufficient amount of intake air, the rotation speed R decreases over one cycle and then increases. In particular, the rotation speed R increases during the expansion stroke. On the other hand, as shown in FIG. 6, when the internal combustion engine 26 is experiencing poor combustion (misfire) due to an insufficient amount of intake air, the rotation speed R decreases over one cycle. In particular, the rotation speed R decreases during the expansion stroke. As a result, the fluctuation range w1 of the rotation speed R when the internal combustion engine 26 is experiencing poor combustion due to an insufficient amount of intake air is smaller than the fluctuation range w2 of the rotation speed R when the internal combustion engine 26 is not experiencing poor combustion due to an insufficient amount of intake air.

[0043] Therefore, the control device 100 can determine whether or not poor combustion is occurring due to an insufficient amount of intake air, based on the fluctuation range w of the rotation speed R of the internal combustion engine 26. That is, the control device 100 determines whether or not the fluctuation range w of the rotation speed R is smaller than a predetermined range w0. If the fluctuation range w of the rotation speed R is smaller than the predetermined range w0, the control device 100 determines that poor combustion is occurring in the internal combustion engine 26 due to an insufficient amount of intake air. If the fluctuation range w of the rotation speed R is equal to or greater than the predetermined range w0, the control device 100 determines that poor combustion is not occurring in the internal combustion engine 26 due to an insufficient amount of intake air.

[0044] Between times t1 and t2 in FIG. 4, if poor combustion due to an insufficient intake air amount occurs in the internal combustion engine 26, the control device 100 increases the intake air amount F of the internal combustion engine 26. Specifically, the control device 100 increases the opening degree φ of the electronic throttle 32. The control device 100 adds the opening degree correction amount Δφ to the base opening degree φb. As a result, the intake air amount F becomes a value obtained by adding the increase amount ΔF to the base intake air amount Fb. When the intake air amount F increases, the compression end temperature of the combustion chamber rises, and the problem of poor combustion due to an insufficient intake air amount is resolved.

[0045] In this case, the control device 100 determines the intake air amount increase amount ΔF and the intake air amount derivative F' so that the intake air amount and the intake air amount derivative F' increase as the fluctuation range w decreases. That is, the control device 100 determines the opening correction amount Δφ and the derivative value φ' of the opening φ so that the opening correction amount Δφ and the derivative value φ' of the opening φ increase as the fluctuation range w decreases. The derivative value φ' of the opening φ is the derivative value of the opening φ (the slope of the opening φ) from time t1 to time t2 in FIG. 4. Therefore, the storage device 102 stores a first table shown in FIG. 7. The first table shown in FIG. 7 shows the relationship between the fluctuation range w, the opening correction amount Δφ, and the derivative value φ'. The first table shown in FIG. 7 is prepared for each water temperature, intake air temperature, and valve timing, and is learned when the vehicle 10 is manufactured. In FIG. 7, the following equations (1) to (3) hold.

[0046] w1>w2>w3>w4>w5>… (1) Δφ1<Δφ2<Δφ3<Δφ4<Δφ5<… (2) φ'1<φ'2<φ'3<φ'4<φ'5<… (3)

[0047] The control device 100 calculates the fluctuation range w based on the crank angle signal b, and determines the opening correction amount Δφ and the differential value φ′ corresponding to the calculated fluctuation range w.

[0048] However, as shown at times t1 to t3 in FIG. 4, when the intake air amount F increases, the rotation speed R increases. Therefore, as shown at times t3 to t4 in FIG. 4, when the control device 100 is increasing the intake air amount F due to poor combustion caused by a shortage of the intake air amount F, the control device 100 retards the ignition timing of the internal combustion engine 26 from the base ignition timing Tb. The base ignition timing Tb is MBT. This reduces the peak value of pressure during combustion in the combustion chamber. As a result, the output of the internal combustion engine 26 decreases, and the rotation speed R decreases. As a result, the rotation speed R approaches the target rotation speed Rt.

[0049] At this time, the control device 100 determines the delay amount ΔT based on the magnitude of the difference ΔR between the rotation speed R and the target rotation speed Rt. That is, the control device 100 determines the delay amount ΔT so that the delay amount ΔT increases as the difference ΔR increases. Therefore, the storage device 102 stores a second table shown in FIG. 8. The second table shown in FIG. 8 shows the relationship between the difference ΔR and the delay amount ΔT. The second table shown in FIG. 8 is prepared for each water temperature, intake air temperature, and valve timing, and is learned when the vehicle 10 is manufactured. In FIG. 8, the following equations (4) to (5) hold.

[0050] ΔR1<ΔR2<ΔR3<ΔR4<ΔR5<… (4) ΔT1<ΔT2<ΔT3<ΔT4<ΔT5<… (5)

[0051] The control device 100 calculates the difference ΔR based on the crank angle signal b, and determines the retard amount ΔT corresponding to the calculated ΔR. Note that the control device 100 does not advance the ignition timing T from the base ignition timing Tb.

[0052] However, there are cases where the retard amount ΔT determined by the control device 100 is too large. In this case, as combustion progresses during the expansion stroke, the temperature of the combustion chamber decreases over time. During combustion, the temperature of the combustion chamber falls below the temperature required to ignite the air-fuel mixture. As a result, poor combustion occurs in the internal combustion engine 26.

[0053] Therefore, as shown in time t1 to t2 in Fig. 4, the control device 100 determines the upper limit value TG of the ignition timing retard amount ΔT based on the intake air amount F of the internal combustion engine 26. This prevents poor combustion from occurring in the internal combustion engine 26. At this time, the control device 100 determines the upper limit value TG so that the upper limit value TG increases as the intake air amount F increases. Therefore, the storage device 102 stores a third table shown in Fig. 9. The third table shown in Fig. 9 shows the relationship between the intake air amount F and the upper limit value TG. In Fig. 9, the following equations (6) to (7) hold.

[0054] F1 <F2<F3<F4<F5<… ···(6) TG1 <TG2<TG3<TG4<TG5<… ···(7)

[0055] The control device 100 calculates the intake air amount F based on the intake air temperature / intake air pressure signal d, and determines the upper limit value TG corresponding to the calculated intake air amount F.

[0056] Next, specific processing executed by the control device 100 will be described with reference to the drawings. Fig. 10 is a diagram showing a flowchart executed by the control device 100. The control device 100 executes the flowchart of Fig. 10 by reading out a program stored in the storage device 102.

[0057] First, the control device 100 calculates a target rotation speed Rt of the internal combustion engine 26 based on a vehicle speed signal a, a crank angle signal b, an accelerator opening signal c, an intake air temperature / intake pressure signal d, a cooling water temperature signal e, and an atmospheric pressure signal f (step S1), and also estimates a base intake air amount Fb to be filled into the cylinders of the internal combustion engine 26 (step S2).

[0058] Next, the control device 100 determines the fuel injection amount, fuel injection timing, fuel injection pressure, base ignition timing Tb, and base opening φb based on the target rotation speed Rt and base intake air amount Fb of the internal combustion engine 26 (step S3). In this embodiment, the base ignition timing Tb is MBT.

[0059] Next, the control device 100 controls the injector 31, the spark plug 30, and the electronic throttle 32 based on the fuel injection amount, fuel injection timing, fuel injection pressure, base ignition timing Tb, and base opening φb (step S4). More specifically, the control device 100 generates an ignition signal h, a fuel injection signal i, and an opening control signal j based on the fuel injection amount, fuel injection timing, fuel injection pressure, base ignition timing Tb, and base opening φb. The ignition signal h is output to the igniter. The igniter generates a spark in the spark plug 30 based on the ignition signal h. The fuel injection signal i is output to the injector 31. The injector 31 injects fuel based on the fuel injection signal i. The opening control signal j is output to the electronic throttle 32. The electronic throttle 32 opens and closes the throttle valve based on the opening control signal j.

[0060] Next, the control device 100 determines whether or not poor combustion is occurring in the internal combustion engine 26 due to an insufficient intake amount (step S5). In step S5, the control device 100 determines whether or not the fluctuation width w of the rotation speed R of the internal combustion engine 26 is smaller than a predetermined width w0. If the fluctuation width w of the rotation speed R is smaller than the predetermined width w0, the control device 100 determines that poor combustion is occurring in the internal combustion engine 26. After this, the process proceeds to step S6. If the fluctuation width w of the rotation speed R is equal to or greater than the predetermined width w0, the control device 100 determines that poor combustion is not occurring in the internal combustion engine 26. After this, the process returns to step S1.

[0061] If poor combustion is occurring in the internal combustion engine 26, the control device 100 determines the opening correction amount Δφ and the derivative value φ' based on the fluctuation range w of the rotation speed R (step S6). In step S6, the control device 100 determines the opening correction amount Δφ and the derivative value φ' corresponding to the fluctuation range w of the rotation speed R by referring to the first table shown in FIG.

[0062] Next, the control device 100 calculates the intake air amount F based on the intake air temperature / intake air pressure signal d, and determines an upper limit value TG corresponding to the calculated intake air amount F (step S7). In step S7, the control device 100 determines the upper limit value TG corresponding to the intake air amount F by referring to a third table shown in FIG.

[0063] Next, the control device 100 controls the electronic throttle 32 so that the opening φ becomes the sum of the base opening φb and the opening correction amount Δφ (step S8). At this time, the control device 100 controls the electronic throttle 32 so that the opening φ changes according to the differential value φ'.

[0064] Next, the control device 100 determines the delay amount ΔT based on the magnitude of the difference ΔR between the target rotation speed Rt and the rotation speed R (step S9). In step S9, the control device 100 determines the delay amount ΔT corresponding to the difference ΔR by referring to the second table shown in FIG.

[0065] Next, the control device 100 determines whether the delay amount ΔT is greater than the upper limit value TG (step S10). If the delay amount ΔT is not greater than the upper limit value TG, the process proceeds to step S11. If the delay amount ΔT is greater than the upper limit value TG, the process proceeds to step S12.

[0066] If the retard amount ΔT is not greater than the upper limit value TG, the control device 100 controls the ignition timing using the retard amount ΔT (step S11). Specifically, the control device 100 causes the spark plug 30 to generate a spark at a timing retarded by the retard amount ΔT from the base ignition timing Tb. After this, the process ends.

[0067] If the retard amount ΔT is greater than the upper limit value TG, the control device 100 controls the ignition timing using the upper limit value TG (step S12). Specifically, the control device 100 causes the spark plug 30 to generate a spark at a timing retarded by the upper limit value TG relative to the base ignition timing Tb. After this, the process ends.

[0068] [effect] The control device 100 can suppress the occurrence of poor combustion such as slow combustion and misfires. More specifically, when poor combustion due to an insufficient intake air amount occurs in the internal combustion engine 26, the control device 100 increases the intake air amount of the internal combustion engine 26. As a result, the intake air amount F becomes a value obtained by adding the increase amount ΔF to the base intake air amount Fb. When the intake air amount F increases, the compression end temperature of the combustion chamber rises, and the problem of poor combustion due to an insufficient intake air amount is resolved.

[0069] However, when the intake air amount F increases, the rotation speed R increases. Therefore, the control device 100 retards the ignition timing of the internal combustion engine 26. This reduces the peak value of the pressure in the combustion chamber. As a result, the output of the internal combustion engine 26 decreases, and the rotation speed R decreases. As a result, the rotation speed R approaches the target rotation speed Rt.

[0070] The control device 100 can suppress the occurrence of poor combustion such as slow combustion and misfires by using signals from existing sensors. Therefore, the control device 100 does not require changing the design of the internal combustion engine 26 or adding new sensors.

[0071] The control device 100 can also suppress poor combustion, such as slow combustion and misfires, for the following reasons. More specifically, the retard amount ΔT determined by the control device 100 may be too large. In this case, the temperature of the combustion chamber decreases over time as combustion progresses in the expansion stroke. During combustion, the temperature of the combustion chamber falls below the temperature required to ignite the air-fuel mixture. As a result, poor combustion occurs in the internal combustion engine 26.

[0072] Therefore, the control device 100 determines the upper limit value TG of the retard amount ΔT of the ignition timing based on the intake air amount F of the internal combustion engine 26. This prevents poor combustion from occurring in the internal combustion engine 26.

[0073] (Other embodiments) The control device according to the present invention is not limited to the control device 100, and can be modified within the scope of the gist thereof.

[0074] The fuel may be a hydrocarbon fuel other than gasoline, or an alcohol fuel such as bioethanol fuel.

[0075] The automobile may be a three-wheeled automobile or a two-wheeled automobile. The two-wheeled automobile is a leaning vehicle in which the body leans in the same direction as the direction of travel around the corner. The three-wheeled automobile may be a leaning vehicle or a vehicle that rolls in the opposite direction to the direction of travel around the corner.

[0076] The control device 100 may determine whether or not poor combustion is occurring in the internal combustion engine due to an insufficient amount of intake air based on information other than the fluctuation range of the rotation speed of the internal combustion engine 26. Furthermore, the control device 100 may diagnose whether or not poor combustion is occurring in the internal combustion engine due to an insufficient amount of intake air by diagnosing the combustion state from the ion current flowing through the electrodes of the spark plug 30 (Japanese Patent Laid-Open Publication No. 11-036971), or may diagnose from the torque value of the generator 50 directly connected to the internal combustion engine 26.

[0077] The control device 100 executes the flowchart of Fig. 10 in a light load region. The light load region is, for example, a load region in which the internal combustion engine 26 is operating in an idling state. However, the control device 100 may execute the flowchart of Fig. 10 in a region other than the light load region.

[0078] The internal combustion engine 26 may be a two-stroke engine. [Explanation of symbols]

[0079] 10: Vehicle 26: Internal combustion engine 27: Piston 29: Crankshaft 30: Spark plug 31: Injector 32: Electronic throttle 36: Battery 38: Crank angle sensor 42: Throttle position sensor 50: Generator 52: Motor 54: Inverter 56: Power transmission device 58L: Left front wheel 58R: Right front wheel 100: Control device 102: Storage device

Claims

1. A control device for an internal combustion engine, When poor combustion occurs in the internal combustion engine due to an insufficient amount of intake air, the control device increases the amount of intake air of the internal combustion engine and retards the ignition timing of the internal combustion engine. Control device.

2. the control device determines whether or not the poor combustion has occurred based on a fluctuation range of the rotation speed of the internal combustion engine. The control device according to claim 1 .

3. the control device determines an upper limit value of the retard amount of the ignition timing based on an intake air amount of the internal combustion engine. The control device according to claim 2 .

4. the control device determines the increase amount of the intake air amount and the derivative value of the intake air amount so that the increase amount of the intake air amount and / or the derivative value of the intake air amount increases as the fluctuation range decreases. The control device according to claim 2 or 3.

5. When the control device is increasing the intake air amount due to poor combustion caused by a lack of intake air amount in the internal combustion engine, the control device retards the ignition timing of the internal combustion engine from MBT (Minimum Spark Advance for Best Torque). The control device according to claim 1 or 2.

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