Start control device for internal combustion engine and computer program

Abstract

To provide a start control device for an internal combustion engine, capable of inhibiting start of an internal combustion engine which is not intended by a driver.SOLUTION: A start control device for controlling start of an internal combustion engine executes: engine start / stop determination processing to generate a request to stop the internal combustion engine when an accelerator opening set by a driver is less than a predetermined opening threshold, and generate a request to start the internal combustion engine when the accelerator opening set by the driver becomes equal to or greater than the predetermined opening threshold; learning processing to learn an accelerator operation characteristic of the driver when a vehicle is started or accelerated; and internal combustion engine start processing to execute, on the basis of a result of learning the accelerator operation characteristic, first start processing to start the internal combustion engine when the accelerator opening becomes equal to or greater than the predetermined opening threshold, and second start processing to start the internal combustion engine after a state in which the accelerator opening is equal to or greater than the predetermined opening threshold continues for a predetermined time.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present disclosure relates to a start control device and a computer program for controlling the start of an internal combustion engine mounted on a hybrid vehicle. [Background technology]

[0002] Hybrid vehicles equipped with a drive motor and an internal combustion engine are known as driving power sources for vehicles such as automobiles. One type of hybrid vehicle system is configured to stop the internal combustion engine when the vehicle is stopped or when the required drive torque is extremely small, and start the internal combustion engine when the required drive torque increases, so that the drive motor and the internal combustion engine work together to output the required drive torque. In such hybrid vehicles, priority is given to electric driving using the output of the drive motor, thereby improving fuel efficiency.

[0003] In such hybrid vehicles, one of the conditions for starting the stopped internal combustion engine is the driver's depression of the accelerator pedal. In other words, when the accelerator pedal is depressed, it can be determined that the driver is requesting vehicle drive torque, and the control device starts the internal combustion engine. For example, Patent Document 1 discloses a hybrid vehicle that starts the internal combustion engine when the accelerator opening required for the vehicle during electric driving reaches or exceeds a predetermined threshold. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-15476 Summary of the Invention [Problem to be solved by the invention]

[0005] It is known that the operation of the accelerator pedal by the driver has operation characteristics that are not related to driving skill. For example, the following three characteristics can be given as examples of accelerator pedal operation characteristics ("accelerator operation characteristics"). First characteristic: The amount of depression is large at the start of the depression operation, but the maximum amount of depression is limited to a predetermined level, and thereafter the change in the amount of depression is small. Second characteristic: The accelerator pedal is operated with a relatively small amount of pressure throughout the entire operation, but the amount of pressure changes with large fluctuations. Third characteristic: The amount of depression gradually increases when the pedaling motion starts, reaches a maximum value, then decreases rapidly, and thereafter the change in the amount of depression remains small.

[0006] When a driver with the third characteristic depresses the accelerator pedal, the accelerator opening degree significantly exceeds the intended target accelerator opening degree. Therefore, even if the intended accelerator opening degree is less than the predetermined threshold value for starting the internal combustion engine, the accelerator opening degree exceeds the predetermined threshold value due to the depressing action, making it easier for the internal combustion engine to start compared to drivers with other accelerator operation characteristics.

[0007] The present disclosure has been made in consideration of the above-mentioned problems, and an object of the present disclosure is to provide an internal combustion engine start control device and a computer program that can suppress the start of an internal combustion engine that is not intended by the driver. [Means for solving the problem]

[0008] In order to solve the above-described problems, according to one aspect of the present disclosure, there is provided a start control device for controlling start of an internal combustion engine in a hybrid vehicle that includes a drive motor and an internal combustion engine as drive power sources of the vehicle, the start control device comprising: one or more processors; and one or more memories communicatively coupled to the one or more processors; the one or more processors: an engine start / stop determination process that generates a stop request for the internal combustion engine when an accelerator opening by the driver is less than a predetermined opening threshold, and generates a start request for the internal combustion engine when the accelerator opening by the driver is equal to or greater than the predetermined opening threshold; a learning process for learning accelerator operation characteristics of the driver when the vehicle starts or accelerates; an internal combustion engine starting process that executes, based on a learning result of the accelerator operation characteristic, a first starting process that starts the internal combustion engine when the accelerator opening becomes equal to or greater than the predetermined opening threshold, and a second starting process that starts the internal combustion engine after the accelerator opening has remained equal to or greater than the predetermined opening threshold for a predetermined period of time; A starting control device for an internal combustion engine is provided.

[0009] According to another aspect of the present disclosure, there is provided a computer program applied to a start control device that controls start of an internal combustion engine in a hybrid vehicle that includes a drive motor and an internal combustion engine as drive power sources of the vehicle, the computer program comprising: one or more processors, an engine start / stop determination process that generates a stop request for the internal combustion engine when an accelerator opening by the driver is less than a predetermined opening threshold, and generates a start request for the internal combustion engine when the accelerator opening by the driver is equal to or greater than the predetermined opening threshold; a learning process for learning accelerator operation characteristics of the driver when the vehicle starts or accelerates; an internal combustion engine starting process that executes, based on a learning result of the accelerator operation characteristic, a first starting process that starts the internal combustion engine when the accelerator opening becomes equal to or greater than the predetermined opening threshold, and a second starting process that starts the internal combustion engine after the accelerator opening has remained equal to or greater than the predetermined opening threshold for a predetermined period of time; A computer program is provided for causing the [Effects of the Invention]

[0010] As described above, according to the present disclosure, it is possible to prevent the internal combustion engine from starting unintentionally by the driver. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram illustrating an example of the configuration of a vehicle equipped with a start control device for an internal combustion engine according to an embodiment of the present disclosure. [Figure 2] 2 is a block diagram showing a functional configuration of a control device (start control device) according to the embodiment; FIG. [Figure 3] FIG. 4 is an explanatory diagram showing an example of accelerator operation characteristics. [Figure 4] 4 is a flowchart showing an example of an operation of a start control process for an internal combustion engine performed by the control device according to the embodiment; [Figure 5] 4 is a flowchart showing an example of an operation of a start control process for an internal combustion engine performed by the control device according to the embodiment; [Figure 6] 10A and 10B are explanatory diagrams showing a reference example for explaining the action of the control device according to the embodiment; [Figure 7] 4 is an explanatory diagram for explaining the operation of the control device according to the embodiment; FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0013] 1. Features of the embodiments of the present disclosure (1-1) An embodiment of the present disclosure is a start control device that controls the start of an internal combustion engine in a hybrid vehicle that has a drive motor and an internal combustion engine as a drive power source of the vehicle, one or more processors; and one or more memories communicatively coupled to the one or more processors; the one or more processors: a driving mode setting process that sets the vehicle to an electric driving mode in which the vehicle is driven by a driving torque output from the drive motor when the accelerator opening by the driver is less than a predetermined opening threshold, and sets the vehicle to a hybrid driving mode in which the internal combustion engine is started and the vehicle is driven by the driving torque output from the drive motor and the internal combustion engine when the accelerator opening by the driver becomes equal to or greater than the predetermined opening threshold; a learning process for learning accelerator operation characteristics of the driver when the vehicle starts moving or accelerates in the electric travel mode; an internal combustion engine starting process that executes, based on a learning result of the accelerator operation characteristic, a first starting process that starts the internal combustion engine when the accelerator opening becomes equal to or greater than the predetermined opening threshold, or a second starting process that starts the internal combustion engine after the accelerator opening has remained equal to or greater than the predetermined opening threshold for a predetermined period of time; The system has a configuration for performing the above steps.

[0014] In addition, the embodiments of the present disclosure can also be realized by an internal combustion engine start control device mounted on a vehicle that executes each of the above processes, a computer program for executing each of the above processes, a recording medium on which the computer program is recorded, or an internal combustion engine start control method that executes each of the above processes.

[0015] With the above configuration, the internal combustion engine start control device and the like disclosed herein learn accelerator operation characteristics when a driver operating a vehicle with the internal combustion engine stopped depresses the accelerator pedal, and vary the start timing of the internal combustion engine based on the learned accelerator operation characteristics. Specifically, the start control device executes a first start process that starts the internal combustion engine when the accelerator opening becomes equal to or greater than a predetermined opening threshold, or a second start process that starts the internal combustion engine after the accelerator opening has remained equal to or greater than the predetermined opening threshold for a predetermined period of time, depending on the driver's accelerator operation characteristics. This makes it possible to prevent the internal combustion engine from starting unintentionally when a driver with accelerator operation characteristics that increases the amount of depression when the accelerator pedal is first depressed. On the other hand, when a driver without accelerator operation characteristics that increases the amount of depression when the accelerator pedal is first depressed deeply, the internal combustion engine is started appropriately, and the driver's acceleration request can be realized.

[0016] The "accelerator opening" refers to the amount of depression of the accelerator pedal. The "predetermined opening threshold" refers to a threshold for determining whether the internal combustion engine will start due to the driver's depression of the accelerator pedal. The "predetermined opening threshold" is set to an accelerator opening value corresponding to the maximum value of the required drive torque that can be achieved solely by the drive torque output from the drive motor, for example. When the accelerator opening is equal to or greater than the "predetermined opening threshold," the internal combustion engine basically starts, and the required drive torque is achieved by the drive torque output from both the drive motor and the internal combustion engine. However, the start control device of the present disclosure is configured to set the start timing of the internal combustion engine when the accelerator opening is equal to or greater than the predetermined opening threshold in accordance with the driver's accelerator operation characteristics.

[0017] The "accelerator operation characteristics" refers to the driver's habits when depressing the accelerator pedal. As mentioned above, the "accelerator operation characteristics" are typically the following three characteristics, but are not limited to these. First characteristic: The amount of depression is large at the start of the depression operation, but the maximum amount of depression is limited to a predetermined level, and thereafter the change in the amount of depression is small. Second characteristic: The accelerator pedal is operated with a relatively small amount of pressure throughout the entire operation, but the amount of pressure changes with large fluctuations. Third characteristic: The amount of depression gradually increases when the pedaling motion starts, reaches a maximum value, then decreases rapidly, and thereafter the change in the amount of depression remains small.

[0018] (1-2) In addition, in the embodiment of the present disclosure, the one or more processors: In the learning process, the ratio of the number of times the accelerator opening degree becomes equal to or greater than the predetermined opening degree threshold when the vehicle starts moving or accelerates in the electric travel mode to the number of times the accelerator opening degree becomes equal to or greater than the predetermined opening degree threshold within a predetermined time threshold may be calculated.

[0019] This configuration makes it possible to identify a driver having the third characteristic. Therefore, it is possible to accurately determine whether the driver should be subjected to the second start process as the internal combustion engine start process, and to prevent the internal combustion engine from being started unintentionally by the driver. Furthermore, it is possible to quickly start the internal combustion engine when a driver having a different accelerator operation characteristic depresses the accelerator pedal.

[0020] (1-3) In addition, in the embodiment of the present disclosure, the one or more processors: In the internal combustion engine starting process, if the ratio is less than a predetermined ratio threshold, the first starting process may be executed, and if the ratio is equal to or greater than the predetermined ratio threshold, the second starting process may be executed.

[0021] With this configuration, a second start-up process can be applied to drivers who tend to depress the accelerator pedal a large amount when they start depressing the accelerator pedal, in which the internal combustion engine is started after the accelerator opening has remained above a predetermined opening threshold for a predetermined period of time.

[0022] (1-4) In addition, in the embodiment of the present disclosure, the one or more processors: In the second start-up process, when the accelerator opening degree becomes equal to or greater than the predetermined opening degree threshold, a start-up suppression mode is set, When a predetermined first time has elapsed since the start suppression mode was set without the accelerator opening becoming less than the predetermined opening threshold, When the accelerator opening degree again becomes less than the predetermined opening degree threshold before the predetermined first time has elapsed since the start suppression mode was set, and then a predetermined second time has elapsed without the accelerator opening degree again becoming equal to or greater than the predetermined opening degree threshold; and When the accelerator opening degree again becomes less than the predetermined opening degree threshold before the predetermined first time has elapsed since the start suppression mode was set, and then the accelerator opening degree again becomes equal to or greater than the predetermined opening degree threshold before the predetermined second time has elapsed, When any one of the above conditions is met, the setting of the start suppression mode is cancelled, The internal combustion engine may be started when the start suppression mode is released in a state where the accelerator opening is equal to or greater than the predetermined opening threshold.

[0023] With this configuration, it is possible to determine the driver's intention to rapidly increase the drive torque (hereinafter also referred to as "torque rapid increase intention"), who tends to increase the accelerator pedal depression amount when the accelerator pedal starts to be depressed, and to start the internal combustion engine. Therefore, it is possible to prevent the internal combustion engine from not being started even though the driver has the intention to rapidly increase the torque.

[0024] <2. Vehicle configuration> The configuration of a vehicle equipped with a starting control device for an internal combustion engine according to an embodiment of the present disclosure will be described with reference to Fig. 1. Fig. 1 is a schematic diagram showing the configuration of a hybrid vehicle (hereinafter also simply referred to as "vehicle") 1. The vehicle 1 is equipped with an internal combustion engine 11, a drive motor 13, a transmission 15, a battery 17, an inverter 19, wheels 21, and a control device 60. The vehicle 1 is configured as a hybrid vehicle in which the internal combustion engine 11 and the drive motor 13 are provided in parallel as driving force sources.

[0025] The internal combustion engine 11 is typically a gasoline engine or a diesel engine, and a crankshaft 23 serving as an output shaft of the internal combustion engine 11 is connected to the transmission 15. The internal combustion engine 11 generates driving force by burning fuel and outputs the driving force via the crankshaft 23. The crankshaft 23 transmits the driving force output from the internal combustion engine 11 to the transmission 15. The internal combustion engine 11 is equipped with an engine speed sensor 51 that detects the rotation speed of the crankshaft 23.

[0026] The drive motor 13 is, for example, a three-phase AC motor, and a motor rotating shaft 25 serving as an output shaft of the drive motor 13 is connected to the transmission 15. The crankshaft 23 and the motor rotating shaft 25 are connected to each other via the transmission 15. The battery 17 is a power source that stores power supplied to the drive motor 13, and is electrically connected to the inverter 19. The inverter 19 is electrically connected to the drive motor 13, and converts the power of the battery 17 into three-phase AC power and supplies it to the drive motor 13. The drive motor 13 rotates the motor rotating shaft 25 using the power supplied via the inverter 19. The drive motor 13 outputs driving force via the motor rotating shaft 25. The motor rotating shaft 25 transmits the driving force output from the drive motor 13 to the transmission 15.

[0027] The transmission 15 is provided between the crankshaft 23 and the motor rotating shaft 25 and the wheels 21. The transmission 15 changes the rotational speed of the crankshaft 23 and the motor rotating shaft 25, and transmits the driving torque output from the internal combustion engine 11 and the drive motor 13 to the wheels 21. The transmission 15 includes a speed change mechanism 30, a secondary shaft 27, a secondary gear mechanism 40, an output clutch 45, and an output shaft 29. In this embodiment, the speed change mechanism 30 is configured as a continuously variable transmission mechanism, but may be a stepped transmission mechanism.

[0028] The transmission mechanism 30 includes a primary pulley 31, a secondary pulley 33, and a transmission belt 35. The transmission belt 35 is wound around the primary pulley 31 and the secondary pulley 33. The transmission belt 35 transmits the rotation of the primary pulley 31 to the secondary pulley 33, causing the secondary pulley 33 to rotate in accordance with the rotation of the primary pulley 31. The transmission mechanism 30 can adjust the ratio of the rotational speed of the secondary pulley 33 to the rotational speed of the primary pulley 31 by changing the pulley widths of the primary pulley 31 and the secondary pulley 33, respectively.

[0029] The crankshaft 23 and the motor rotary shaft 25 are connected to a primary pulley 31. The primary pulley 31 rotates at the same rotational speed as the crankshaft 23 and the motor rotary shaft 25. In other words, the primary pulley 31, the crankshaft 23, and the motor rotary shaft 25 rotate integrally. However, a clutch mechanism (not shown) may be provided at any position along the crankshaft 23 or the motor rotary shaft 25, so that the connection between the internal combustion engine 11 or the drive motor 13 and the primary pulley 31 can be interrupted.

[0030] The secondary shaft 27 is connected to the secondary pulley 52. ​​The secondary shaft 27 rotates at the same rotational speed as the secondary pulley 33. In other words, the secondary pulley 33 and the secondary shaft 27 rotate integrally. The rotational speed of the secondary shaft 27 is reduced by the transmission mechanism 30 to be slower than the rotational speeds of the crankshaft 23 and the motor rotary shaft 25.

[0031] The secondary gear mechanism 40 includes a first secondary gear 41 and a second secondary gear 43. The first secondary gear 41 is connected to the secondary shaft 27. The first secondary gear 41 rotates at the same rotational speed as the secondary shaft 27. The first secondary gear 41 and the second secondary gear 43 mesh with each other. The rotational speed of the second secondary gear 43 is reduced compared to the rotational speed of the first secondary gear 41.

[0032] The output clutch 45 includes a first clutch plate 47 and a second clutch plate 49. The second secondary gear 43 is connected to the first clutch plate 47. The first clutch plate 47 rotates integrally with the second secondary gear 43. The output shaft 29 is connected to the second clutch plate 49. The output shaft 29 is connected to the wheels 21.

[0033] When the first clutch plate 47 and the second clutch plate 49 are engaged, power is transmitted from the second secondary gear 43 to the output shaft 29. In this case, the output shaft 29 rotates at the same rotational speed as the second secondary gear 43. The wheels 21 rotate in accordance with the rotation of the output shaft 29. The transmission 15 is equipped with an output rotation speed sensor 53 that detects the rotational speed of the output shaft 29.

[0034] The control device 60 functions as a device that controls the driving force of the hybrid vehicle by having one or more processors, such as CPUs (Central Processing Units), execute a computer program. In particular, the control device 60 functions as a start control device that controls the start of the internal combustion engine 11. The computer program is a computer program that causes the processor to execute the operations to be performed by the control device 60, which will be described later. The computer program executed by the processor may be recorded on a recording medium that functions as a memory provided in the control device 60, or may be recorded on a recording medium built into the control device 60 or any recording medium that can be externally attached to the control device 60.

[0035] Recording media for recording computer programs include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical recording media such as CD-ROMs (Compact Disk Read Only Memory), DVDs (Digital Versatile Disks), SSDs (Solid State Drives), and Blu-ray (registered trademark), magneto-optical media such as floptical disks, memory elements such as RAMs and ROMs, and flash memories such as USB (Universal Serial Bus) memories, as well as other media capable of storing programs.

[0036] The control device 60 receives sensor signals from an engine rotation speed sensor 51 and an output rotation speed sensor 53. The control device 60 also receives a sensor signal from an accelerator sensor 55 that detects the amount of depression of the accelerator pedal (accelerator opening).

[0037] <3. Control device (internal combustion engine start control device)> Next, a specific example of the configuration of the control device 60 will be described. The control device 60 includes a processing unit 61 and a storage unit 63. The processing unit 61 includes one or more processors and executes processing to control the driving of the internal combustion engine 11 and the drive motor 13. A part or all of the processing unit 61 may be configured with updatable firmware or the like, or may be a program module executed by commands from a CPU or the like. The storage unit 63 includes one or more memories such as RAM or ROM connected to the processing unit 61 so as to be able to communicate with the processing unit 61, and stores computer programs executed by the processing unit 61, various parameters used in the calculation processing, and information on the calculation results. However, the number and type of storage units 63 are not particularly limited.

[0038] The processing unit 61 includes an accelerator opening determination unit 71, an engine start / stop determination unit 73, a learning unit 75, a required driving torque calculation unit 77, an internal combustion engine control unit 79, and a motor control unit 81. The functions of these units are realized by the execution of a computer program by a processor. However, some of these units may be configured by hardware such as an analog circuit.

[0039] (3-1. Accelerator opening determination section) Accelerator opening determination unit 71 executes an accelerator opening determination process to determine the amount of accelerator pedal operation (accelerator opening) performed by the driver. Specifically, accelerator opening determination unit 71 determines the accelerator opening based on a sensor signal input from accelerator sensor 55.

[0040] (3-2. Engine start / stop determination unit) The engine start / stop determination unit 73 executes an engine start / stop determination process that generates a request to stop the internal combustion engine 11 when the accelerator opening by the driver is less than a predetermined opening threshold, and generates a request to start the internal combustion engine 11 when the accelerator opening by the driver is equal to or greater than the predetermined opening threshold.

[0041] Specifically, the accelerator opening determination unit 71 generates a request to stop the internal combustion engine 11 when the accelerator opening by the driver is less than a predetermined opening threshold, and causes the vehicle 1 to run using the driving force output from the drive motor 13 (electric driving mode). On the other hand, the accelerator opening determination unit 71 generates a request to start the internal combustion engine 11 when the accelerator opening by the driver is equal to or greater than a predetermined opening threshold, and causes the vehicle 1 to run using the driving forces output from the internal combustion engine 11 and the drive motor 13 (hybrid driving mode). Therefore, in the vehicle 1 of this embodiment, the electric driving mode is set when the driving torque required by the driver for the vehicle 1 is small, and the hybrid driving mode is switched to when the driving torque required by the driver for the vehicle 1 becomes large.

[0042] Furthermore, in this embodiment, when the rate of increase in accelerator opening degree is equal to or greater than a predetermined threshold while the internal combustion engine 11 is stopped, the engine start / stop determination unit 73 generates a request to immediately start the internal combustion engine 11 and promptly starts the internal combustion engine 11 regardless of the accelerator operation characteristics of the driver. In other words, when the rate of increase in accelerator opening degree is fast, it is assumed that the driver's acceleration request is clear, and a command to promptly start the internal combustion engine 11 is generated.

[0043] Furthermore, in this embodiment, the engine start / stop determination unit 73 has an idle stop control function that automatically stops the operation of the internal combustion engine 11 when the vehicle 1 is stopped while the internal combustion engine 11 is operating. For example, the engine start / stop determination unit 73 generates a stop request for the internal combustion engine 11 when the vehicle speed acquired based on the sensor signal of the output rotation speed sensor 53 becomes zero while the shift range of the vehicle 1 is in the drive range (D range) and the internal combustion engine 11 is operating.

[0044] (3-3. Learning Department) The learning unit 75 executes a learning process to learn the accelerator operation characteristics of the driver when starting or accelerating the vehicle 1. By executing the learning process, the learning unit 75 determines whether or not the driver has a characteristic in which the depression amount gradually increases when the driver starts to depress the accelerator pedal, reaches a maximum value, then decreases rapidly, and thereafter there is little change in the depression amount (the above-mentioned "third characteristic").

[0045] In this embodiment, the learning unit 75 calculates the ratio of the number of times the accelerator opening becomes equal to or greater than the predetermined opening threshold within a predetermined time threshold to the number of times the accelerator opening becomes equal to or greater than the predetermined opening threshold when the vehicle 1 starts or accelerates. If the calculated ratio is equal to or greater than the predetermined ratio threshold, the learning unit 75 determines that the driver's accelerator operation characteristic corresponds to the third characteristic.

[0046] Examples of accelerator operation characteristics will now be described in detail. Fig. 3 shows the transition of accelerator opening degree when the vehicle starts moving when the accelerator operation characteristics are the first, second, and third examples described above. The bottom of Fig. 3 also shows examples in which a driver having each accelerator operation characteristic starts the vehicle 1 and maintains the accelerator opening degree at the target opening degree Acc_tgt of 5% when the opening degree threshold A for starting the internal combustion engine 11 is 20%.

[0047] When the accelerator operation characteristic is the first example, the accelerator opening becomes large when the accelerator pedal starts to be depressed, but the maximum accelerator opening is kept to a predetermined level, and thereafter the fluctuation of the accelerator opening becomes small. When the accelerator operation characteristic is the second example, after the accelerator pedal starts to be depressed, the accelerator opening degree remains relatively small throughout, but the fluctuations in the accelerator opening degree become large. When the accelerator operation characteristic is the third example, the accelerator opening degree gradually increases when the accelerator pedal starts to be depressed, and after the maximum value reaches a relatively large value, the accelerator opening degree suddenly decreases, and thereafter the fluctuations in the accelerator opening degree become small.

[0048] When the opening degree threshold A and the target opening degree Acc_tgt for starting the internal combustion engine 11 are superimposed on each accelerator operation characteristic, when the accelerator operation characteristic is the first example and the second example, the accelerator opening degree is maintained below the opening degree threshold A, whereas when the accelerator operation characteristic is the third example, the accelerator opening degree is equal to or greater than the opening degree threshold A. Therefore, if the internal combustion engine 11 is started without exception when the accelerator opening degree exceeds the opening degree threshold A, when the accelerator operation characteristic is the third example, the internal combustion engine 11 will be started even though the original target opening degree Acc_tgt is less than the opening degree threshold A.

[0049] (3-4. Required driving torque calculation section) The required driving torque calculation unit 77 executes a process for calculating the required driving torque of the vehicle 1. The required driving torque may be calculated by any of various conventionally known methods, but for example, the required driving torque may be calculated by referring to a driving torque setting map based on the rotation speed of the internal combustion engine 11 acquired based on the sensor signal of the engine rotation speed sensor 51 and the accelerator opening.

[0050] Furthermore, the required drive torque calculation unit 77 allocates the calculated required drive torque to the target drive torques of the internal combustion engine 11 and the drive motor 13. Specifically, if the internal combustion engine control unit 79 has not set a flag (start completion flag) indicating that the process of starting the internal combustion engine 11 has been completed, the required drive torque calculation unit 77 sets the required drive torque as the target drive torque of the drive motor 13.

[0051] On the other hand, if the internal combustion engine control unit 79 has set a start completion flag for the internal combustion engine 11, the required drive torque calculation unit 77 allocates the required drive torque to the respective target drive torques of the internal combustion engine 11 and the drive motor 13. In this case, for example, to prioritize electric driving, if the required drive torque is equal to or less than the rated torque that can be output by the drive motor 13, the required drive torque calculation unit 77 sets the required drive torque as the target drive torque of the drive motor 13. If the required drive torque exceeds the rated torque that can be output by the drive motor 13, the required drive torque calculation unit 77 sets the rated torque of the drive motor 13 as the target drive torque of the drive motor 13, and sets the remaining torque value, which is obtained by subtracting the rated torque of the drive motor 13 from the required drive torque, as the target drive torque of the internal combustion engine 11.

[0052] (3-5. Internal combustion engine control unit) The internal combustion engine control unit 79 executes an internal combustion engine start control process for starting the internal combustion engine 11 and an internal combustion engine operation control process for controlling the operation of the internal combustion engine 11. Specifically, the internal combustion engine control unit 79 controls the operation of the internal combustion engine 11 by controlling the drive of a motor for cranking the internal combustion engine 11, a fuel injection system of the internal combustion engine 11, and the like.

[0053] (Internal combustion engine start control process) The internal combustion engine control unit 79 executes a process to start the internal combustion engine 11 when a start request for the internal combustion engine 11 is generated by the engine start / stop determination unit 73. In this embodiment, based on the learning result of the driver's accelerator operation characteristics by the learning unit 75, the internal combustion engine control unit 79 executes a first start process to start the internal combustion engine 11 when the accelerator opening becomes equal to or greater than a predetermined opening threshold, and a second start process to start the internal combustion engine 11 after the accelerator opening has remained equal to or greater than the predetermined opening threshold for a predetermined period of time.

[0054] That is, if the accelerator operation characteristic of the driver is an operation characteristic other than the above-mentioned third characteristic, the internal combustion engine control unit 79 starts the internal combustion engine 11 promptly when a start request for the internal combustion engine 11 is generated by the engine start / stop determination unit 73 (first start processing). On the other hand, if the accelerator operation characteristic of the driver is the above-mentioned third characteristic, the internal combustion engine control unit 79 starts the internal combustion engine 11 after a state in which the accelerator opening degree is equal to or greater than a predetermined opening degree threshold continues for a predetermined time after the start request for the internal combustion engine 11 is generated by the engine start / stop determination unit 73 (second start processing).

[0055] In particular, in this embodiment, after a start request for the internal combustion engine 11 is generated by the engine start / stop determination unit 73, the internal combustion engine control unit 79 is configured not only to start the internal combustion engine 11 after the accelerator opening has remained above a predetermined opening threshold for a predetermined period of time, but also to start the internal combustion engine 11 when the accelerator opening again becomes above the predetermined opening threshold in an extremely short time thereafter, even if the accelerator opening becomes above the predetermined opening threshold and then falls below the predetermined opening threshold.

[0056] More specifically, the internal combustion engine control unit 79 sets the internal combustion engine 11 to the start suppression mode when the engine start / stop determination unit 73 generates a start request for the internal combustion engine 11, When a predetermined first time period has elapsed since the start request for the internal combustion engine 11 was generated without the accelerator opening becoming less than a predetermined opening threshold, When the accelerator opening becomes less than the predetermined opening threshold again before a predetermined first time has elapsed since a start request for the internal combustion engine 11 was generated, and then a predetermined second time has elapsed without the accelerator opening becoming equal to or greater than the predetermined opening threshold again; and When the accelerator opening degree again becomes less than the predetermined opening degree threshold before a predetermined first time has elapsed since the generation of a start request for the internal combustion engine 11, and then the accelerator opening degree again becomes equal to or greater than the predetermined opening degree threshold before a predetermined second time has elapsed, When any one of the following conditions is met, the start suppression mode setting is cancelled. When the start suppression mode is released with the accelerator opening equal to or greater than a predetermined opening threshold, the internal combustion engine 11 is started. As a result, even if a driver has the third characteristic described above, the internal combustion engine 11 is started appropriately when the driver intends to rapidly increase torque, and the required drive torque desired by the driver can be realized.

[0057] In this embodiment, when the engine start / stop determination unit 73 generates a start request for the internal combustion engine 11, the internal combustion engine control unit 79 sets a start suppression mode flag. When the counter value of a first timer counter that counts the elapsed time from the time when the start request for the internal combustion engine 11 was generated reaches a predetermined first time, the first timer counter is reset. a second timer counter that counts the duration during which the accelerator opening is maintained below the predetermined opening threshold, from the time when the accelerator opening again becomes less than the predetermined opening threshold before the counter value of the first timer counter reaches the predetermined first time, reaches a predetermined second time and is reset; and When the accelerator opening degree again becomes less than the predetermined opening degree threshold before the counter value of the first timer counter reaches a predetermined first time, and then the accelerator opening degree again becomes equal to or greater than the predetermined opening degree threshold before the counter value of the second timer counter reaches a predetermined second time, Therefore, the internal combustion engine control unit 79 starts the internal combustion engine 11 when the start suppression mode flag is released in a state where the accelerator opening is equal to or greater than a predetermined opening threshold.

[0058] Furthermore, in this embodiment, the internal combustion engine control unit 79 is configured to quickly start the internal combustion engine 11 regardless of the driver's accelerator operation characteristics when an immediate start request for the internal combustion engine 11 is generated by the engine start / stop determination unit 73. As a result, even when the driver's intention to rapidly increase torque is clear and the requested drive torque increases suddenly, a drive torque equivalent to the requested drive torque can be output by the drive torque output from the internal combustion engine 11 and the drive motor 13.

[0059] When the starting of the internal combustion engine 11 is completed, the internal combustion engine control unit 79 sets a start completion flag for the internal combustion engine 11. Completion of the starting of the internal combustion engine 11 can be determined based on whether or not a preset condition is met, such as the engine speed being equal to or greater than a predetermined threshold value or the amplitude of the engine speed being less than a predetermined value.

[0060] (Internal combustion engine operation control processing) After the internal combustion engine 11 has been started, the internal combustion engine control unit 79 controls the operation of the internal combustion engine 11 based on the target drive torque of the internal combustion engine 11 calculated by the required drive torque calculation unit 77. The specific method of the internal combustion engine operation control process may be a conventionally known method, but for example, the internal combustion engine control unit 79 sets the fuel injection amount based on the target drive torque, and controls the fuel injection timing, ignition timing, opening timing of the intake valve and exhaust valve, etc., to cause the internal combustion engine 11 to output a drive torque equivalent to the target drive torque.

[0061] Furthermore, when a stop request for the internal combustion engine 11 is generated by the engine start / stop determination unit 73, the internal combustion engine control unit 79 stops the operation of the internal combustion engine 11. Specifically, the internal combustion engine control unit 79 stops the operation of the internal combustion engine 11 by stopping fuel injection into the internal combustion engine 11.

[0062] (3-6. Motor control unit) The motor control unit 81 controls the power supplied to the drive motor 13 based on the target drive torque of the drive motor 13 calculated by the required drive torque calculation unit 77. The specific method of drive control processing of the drive motor 13 may be a conventionally known method, but for example, the motor control unit 81 controls the drive of the switching elements provided in the inverter 19 based on the target drive torque, and controls the voltage and current of the three-phase AC power supplied to the drive motor 13, thereby causing the drive motor 13 to output a drive torque equivalent to the target drive torque.

[0063] <4. Example of operation> Next, among the processing operations of the control device 60 that functions as a start control device according to this embodiment, the operation of the start control processing of the internal combustion engine 11 will be specifically described.

[0064] 4 and 5 are flowcharts showing an example of the operation of the control device 60 for controlling the start of the internal combustion engine 11. In FIG. First, when the hybrid vehicle system including the control device 60 is started (step S11), the engine start / stop determination unit 73 of the processing unit 61 determines whether the vehicle 1 is running electrically or is stopped (step S13). If the determination in step S13 is negative, that is, if the internal combustion engine 11 is in operation and the vehicle 1 is running (S13 / No), the engine start / stop determination unit 73 repeatedly executes the determination in step S13.

[0065] On the other hand, if the vehicle 1 is running electrically or is stopped (S13 / Yes), the engine start / stop determination unit 73 determines whether the rate of change ΔAcc (% / second) of the accelerator opening Acc is equal to or greater than a predetermined threshold value B (step S15). Step S15 is a process for determining whether the driver has suddenly depressed the accelerator pedal, and the threshold value B may be set to any value in advance.

[0066] If the rate of change ΔAcc of the accelerator opening is equal to or greater than a predetermined threshold B (S15 / Yes), it is considered that the driver desires rapid acceleration, and therefore the engine start / stop determination unit 73 generates an immediate start request for the internal combustion engine 11 (step S17). In this case, the internal combustion engine control unit 79 of the processing unit 61 sets an engine start flag (step S19) and starts the internal combustion engine 11 immediately regardless of the accelerator operation characteristics of the driver (step S21).

[0067] On the other hand, if the rate of change ΔAcc of the accelerator opening is less than the predetermined threshold B (S15 / No), the engine start / stop determination unit 73 determines whether the accelerator opening Acc is equal to or greater than the predetermined opening threshold A (step S27). If the accelerator opening Acc is less than the predetermined opening threshold A (S27 / No), the required drive torque can be output only with the drive torque output from the drive motor 13, and therefore there is no need to start the internal combustion engine 11. Therefore, the engine start / stop determination unit 73 returns to step S13 and repeatedly executes the processing of each of the above-mentioned steps.

[0068] On the other hand, if the accelerator opening Acc is equal to or greater than the predetermined opening threshold A (S27 / Yes), the engine start / stop determination unit 73 generates a start request for the internal combustion engine 11 (step S29). Next, the learning unit 75 determines whether the number of times (N1) the internal combustion engine 11 has been started by the accelerator opening Acc is equal to or greater than a predetermined threshold C (N1≧C) and whether the ratio (%) of the number of times (N2) the accelerator opening Acc became equal to or greater than the predetermined opening threshold A but returned below the predetermined opening threshold A within a predetermined first time period and the internal combustion engine 11 was not started to the number of times (N3) the accelerator opening Acc became equal to or greater than the predetermined opening threshold A and a start request was generated is equal to or greater than a predetermined threshold D (N2 / N3)≧D (step S31).

[0069] The number of times (N1) that the internal combustion engine 11 was started by the accelerator opening Acc is the number of times that the internal combustion engine 11 was actually started due to the accelerator opening Acc becoming equal to or greater than a predetermined opening threshold A while the internal combustion engine 11 was stopped, and does not include the number of times that the internal combustion engine 11 was started because the rate of change ΔAcc of the accelerator opening Acc was determined to be equal to or greater than a predetermined threshold B in step S15 described above. The number of times (N1) that the internal combustion engine 11 was started by the accelerator opening Acc corresponds to the sum of the number of times that the internal combustion engine 11 was started after a predetermined first time period had elapsed since the accelerator opening Acc became equal to or greater than the predetermined opening threshold A without becoming less than the predetermined opening threshold A, and the number of times that the accelerator opening Acc returned to less than the predetermined opening threshold A within the predetermined first time period, but then became equal to or greater than the predetermined opening threshold A again before a predetermined second time period had elapsed, thereby starting the internal combustion engine 11.

[0070] The predetermined threshold C is a threshold for determining whether a sufficient number of samples has been obtained to ensure the accuracy of determining whether the driver's accelerator operation characteristic is the third characteristic, and may be set to any value in advance.

[0071] The number N3 of times the accelerator opening Acc becomes equal to or greater than the predetermined opening threshold A and a start request is generated corresponds to the sum of the number (N1) of times the accelerator opening Acc becomes equal to or greater than the predetermined opening threshold A and the internal combustion engine 11 is actually started, and the number (N2) of times the accelerator opening Acc becomes equal to or greater than the predetermined opening threshold A but returns below the predetermined opening threshold A within a predetermined first time period, preventing the internal combustion engine 11 from starting (N3 = N1 + N2). In other words, the number (N3) is an index value indicating the third characteristic in which the accelerator opening Acc becomes equal to or greater than the predetermined opening threshold A but then falls below the predetermined opening threshold A in a short period of time and is maintained in that state. Therefore, in step S31, it is determined whether the driver's accelerator operation characteristic strongly exhibits a tendency toward the third characteristic in a situation in which a large number of samples are obtained in which the internal combustion engine 11 is started by the accelerator opening Acc.

[0072] If the determination in step S31 is negative (S31 / No), the driver's accelerator operation characteristic is considered to be an operation characteristic other than the third characteristic, and therefore the internal combustion engine control unit 79 sets the engine start flag (step S19) and promptly starts the internal combustion engine 11 (step S21). The process of starting the internal combustion engine 11 in the flow of steps S27, S29, S31, S19, and S21 corresponds to the first start process.

[0073] On the other hand, if the determination in step S31 is affirmative (S31 / Yes), it is considered that the driver's accelerator operation characteristic is the third characteristic. In this case, the internal combustion engine control unit 79 sets the start suppression mode flag (step S33). As a result, even if the accelerator opening Acc becomes equal to or greater than the predetermined opening threshold A due to the operation of the accelerator pedal by the driver having the third characteristic, the internal combustion engine 11 is immediately set to a mode in which it is not started.

[0074] Next, the internal combustion engine control unit 79 determines whether the elapsed time (standby time) since the start request for the internal combustion engine 11 was generated has reached a predetermined first time E (step S35). Specifically, the internal combustion engine control unit 79 determines whether the standby time T1 measured by the first timer counter has reached the predetermined first time E. The first time E is a time for determining that even a driver with the third characteristic is depressing the accelerator opening Acc with the intention of rapidly increasing torque, and is set to an arbitrary value in advance. If the first time E is too short, the number of times the internal combustion engine 11 is started in situations where it should not actually be started increases. On the other hand, if the first time E is too long, the start of the internal combustion engine 11 may be delayed despite the driver's intention of rapidly increasing torque, which may reduce the driver's confidence. In light of this, the first time E may be set to a value within a range of, for example, 5 to 15 seconds.

[0075] If the waiting time T1 reaches the predetermined first time E (S35 / Yes), it is considered that the driver intends to rapidly increase the torque. In this case, the learning unit 75 of the processing unit 61 counts up (+1) the counter value N1 of the counter that measures the number of times the internal combustion engine 11 has been started due to the accelerator opening Acc (step S37). Next, the internal combustion engine control unit 79 cancels the start suppression mode flag (step S39), and then sets the engine start flag (step S19), and starts the internal combustion engine 11 (step S21).

[0076] On the other hand, if the standby time T1 has not reached the predetermined first time E (S35 / No), the internal combustion engine control unit 79 determines whether or not the accelerator opening Acc continues to be equal to or greater than the predetermined opening threshold A (step S41). If the accelerator opening Acc continues to be maintained at or greater than the predetermined opening threshold A (S41 / Yes), the process returns to step S35, and the internal combustion engine control unit 79 repeats the process of determining whether or not the elapsed time (standby time) since the start request for the internal combustion engine 11 was generated has reached the predetermined first time E (step S35).

[0077] On the other hand, if the accelerator opening Acc has fallen below the predetermined opening threshold A (S41 / No), the internal combustion engine control unit 79 determines whether or not the elapsed time (duration) since the accelerator opening Acc fell below the predetermined opening threshold A has reached a predetermined second time F (step S43). Specifically, the internal combustion engine control unit 79 determines whether or not the duration T2 measured by a second timer counter that counts the elapsed time since the accelerator opening Acc fell below the predetermined opening threshold A has reached the predetermined second time F.

[0078] The second time F is a time for determining that a driver having the third characteristic has depressed the accelerator pedal position Acc with the intention of rapidly increasing torque, but that the accelerator pedal position Acc has simply temporarily fallen below the predetermined position threshold A for some reason, and is set to an arbitrary value in advance. If the second time F is too short, the duration T2 measured by the second timer counter is more likely to be reset, which could delay the start of the internal combustion engine 11 despite the driver's intention to rapidly increase torque. On the other hand, if the second time F is too long, there is a risk that the internal combustion engine 11 will be started more often even though the driver does not intend to rapidly increase torque. In light of this, the second time F can be set to a value within a range of 5 to 15 seconds, for example.

[0079] If the duration T2 reaches the predetermined second time F (S43 / Yes), it is considered that the accelerator operation characteristic has caused the accelerator opening Acc to become equal to or greater than the predetermined opening threshold A, even though the driver has no intention of rapidly increasing torque. In this case, the learning unit 75 increments (by 1) the counter value (N2) of the counter that measures the number of times the accelerator opening Acc became equal to or greater than the predetermined opening threshold A but returned below the predetermined opening threshold A within the predetermined first time E, preventing the internal combustion engine 11 from starting (step S45). Next, the internal combustion engine control unit 79 cancels the start suppression mode flag (step S47). In this case, the processing unit 61 returns to step S13 and repeatedly executes the processes of the steps described so far.

[0080] On the other hand, if the duration T2 has not reached the predetermined second time F (S41 / No), the internal combustion engine control unit 79 again determines whether the accelerator opening Acc has become equal to or greater than the predetermined opening threshold A (step S49). If the accelerator opening Acc continues to be maintained below the predetermined opening threshold A (S49 / No), the internal combustion engine control unit 79 returns to step S43 and repeatedly determines whether the duration T2 measured by has reached the predetermined second time F (step S43).

[0081] On the other hand, if the accelerator opening Acc becomes equal to or greater than the predetermined opening threshold A again (S49 / Yes), it is considered that the driver intends to rapidly increase torque even though the accelerator opening Acc temporarily became less than the predetermined opening threshold A for some reason. In this case, the learning unit 75 increments (by 1) the counter value N1 of the counter that measures the number of times the internal combustion engine 11 has been started due to an increase in the accelerator opening Acc (step S37). Next, the internal combustion engine control unit 79 cancels the start suppression mode flag (step S39), sets the engine start flag (step S19), and starts the internal combustion engine 11 (step S21).

[0082] The process of starting the internal combustion engine 11 or suppressing the start of the internal combustion engine 11 via steps S27, S29, S31, and steps S33 to S49 corresponds to the second start process. Furthermore, the process of measuring or calculating a predetermined number of times (N1 to N3) while the processes of steps S27 to S49 are being executed corresponds to the process of learning the accelerator operation characteristics of the driver.

[0083] After the internal combustion engine 11 is started by the first start processing and the second start processing (after the internal combustion engine 11 is started in step S21), the internal combustion engine control unit 79 sets a start completion flag when the start of the internal combustion engine 11 is completed (step S23). As a result, the internal combustion engine control unit 79 transitions to the internal combustion engine operation control processing.

[0084] Next, the internal combustion engine control unit 79 determines whether the system of the hybrid vehicle has stopped (step S25). If the system of the hybrid vehicle has not stopped (S25 / No), the processing unit 61 returns to step S13 and repeats the processing of each step described so far. On the other hand, if the system of the hybrid vehicle has stopped (S25 / Yes), the processing unit 61 ends the start control processing of the internal combustion engine 11.

[0085] As described above, the control device 60 according to this embodiment learns the accelerator operation characteristics of the driver, and determines whether to promptly start the internal combustion engine 11 when the accelerator opening Acc becomes equal to or greater than a predetermined opening threshold A, or to wait for the internal combustion engine 11 to start, depending on whether the accelerator operation characteristics of the driver correspond to the third characteristic. This makes it possible to prevent the internal combustion engine 11 from starting unintentionally when a driver having the third characteristic depresses the accelerator pedal. Furthermore, when a driver having the third characteristic depresses the accelerator pedal with the intention of rapidly increasing torque, the internal combustion engine 11 is started appropriately. On the other hand, when a driver having a characteristic other than the third characteristic depresses the accelerator pedal deeply, the internal combustion engine is started appropriately, and the driver's acceleration request can be realized.

[0086] <5. Application Examples> Next, the operation of the start control process of the internal combustion engine 11 to which the technology of the present disclosure is applied will be described.

[0087] 6 and 7 both show the start control process for the internal combustion engine 11 based on the accelerator pedal depression operation by the driver when the accelerator operation characteristic has the third characteristic. FIG. 6 is an explanatory diagram showing the start control process for the internal combustion engine 11 in a state where the learning process has not determined that the driver's accelerator operation characteristic has the third characteristic. That is, FIG. 6 shows an example in which the internal combustion engine 11 is started when the accelerator opening Acc becomes equal to or greater than a predetermined opening threshold A. Furthermore, FIG. 7 is an explanatory diagram showing the start control process for the internal combustion engine 11 when the learning process has determined that the driver's accelerator operation characteristic has the third characteristic.

[0088] 6 and 7 respectively show the counter value N1 of a counter that measures the number of times the internal combustion engine 11 has been started by the accelerator opening Acc, the on / off state (-) of the start suppression mode flag Fg1, the waiting time T1 (sec) measured by the first timer counter, the duration T2 (sec) measured by the second timer counter, the counter value N2 of a counter that measures the number of times the accelerator opening Acc has fallen below the predetermined opening threshold A before the waiting time T1 after the accelerator opening Acc has become equal to or greater than the predetermined opening threshold A reaches the predetermined first time E, and the internal combustion engine 11 has not been started, the on / off state (-) of the engine start flag Fg2, and the engine speed Ne (rpm).

[0089] The accelerator opening Acc is obtained based on a sensor signal from the accelerator sensor 55, and varies according to the amount of depression of the accelerator pedal by the driver. The engine speed Ne is obtained based on a sensor signal from the engine speed sensor 51, and varies according to the operating state of the internal combustion engine 11.

[0090] The counter value N1 of the counter that measures the number of times the internal combustion engine 11 is started by the accelerator opening Acc is incremented when the internal combustion engine 11 is started due to the accelerator opening Acc becoming equal to or greater than a predetermined opening threshold A while the internal combustion engine 11 is stopped (step S37 in FIG. 5). The counter value N1 is not reset to zero, and is only incremented when a condition is satisfied.

[0091] The start suppression mode flag Fg1 is set (turned on) when the accelerator opening Acc becomes equal to or greater than a predetermined opening threshold A while the internal combustion engine 11 is stopped. The start suppression mode flag Fg1 is also cleared (turned off) when either the waiting time T1 measured by the first timer counter is reset or the duration time T2 measured by the second timer counter is reset.

[0092] The waiting time T1 (sec) measured by the first timer counter starts to be measured when the start-up suppression mode flag Fg1 is set, and is reset to zero when the waiting time T1 reaches a predetermined first time E.

[0093] The duration T2 (sec) measured by the second timer counter begins to be measured when the accelerator opening Acc becomes less than a predetermined opening threshold A while the start suppression mode flag Fg1 is set, and is reset to zero when the accelerator opening Acc becomes equal to or greater than the predetermined opening threshold A and when the duration T2 reaches a predetermined second time F.

[0094] A counter value N2 of a counter that measures the number of times the accelerator pedal position Acc falls below the predetermined opening threshold A before the standby time T1 after the accelerator pedal position Acc becomes equal to or greater than the predetermined opening threshold A reaches the predetermined first time E and the internal combustion engine 11 is not started is counted up (+1) when the duration T2 measured by the second timer counter reaches the predetermined second time F (step S45 in FIG. 5). The counter value N2 is not reset to zero, but is only counted up when the condition is satisfied.

[0095] If the learning process has not determined that the driver's accelerator operation characteristic is the third characteristic, the engine start flag Fg2 is set (turned on) when the accelerator opening Acc becomes equal to or greater than a predetermined opening threshold A, and is released (turned off) when the accelerator opening Acc falls below the predetermined opening threshold A. Also, if the learning process has determined that the driver's accelerator operation characteristic is the third characteristic, the engine start flag Fg2 is set (turned on) when the accelerator opening Acc becomes equal to or greater than the predetermined opening threshold A and when the start suppression mode flag Fg1 changes from on to off, and is released (turned off) when the accelerator opening Acc falls below the predetermined opening threshold A.

[0096] The on / off state of the start suppression mode flag Fg1, the waiting time T1, the duration T2, and the counter value N2 operate in the same manner regardless of whether the driver's accelerator operation characteristic is determined to be the third characteristic or not.

[0097] In the examples shown in FIGS. 6 and 7, depression of the accelerator pedal begins at time t0, and when the accelerator opening Acc reaches a predetermined opening threshold A at time t1, the start suppression mode flag Fg1 is set, and the first timer counter starts measuring the standby time T1. In the example of FIG. 6, where the learning process has not determined that the driver's accelerator operation characteristic is the third characteristic (the counter value N1 has not reached the threshold C), the engine start flag Fg2 is set at time t1, and the internal combustion engine 11 is started (the engine speed Ne increases). Accordingly, the counter value N1, which measures the number of times the internal combustion engine 11 has been started due to the accelerator opening Acc, is counted up. On the other hand, in the example of FIG. 7, where the learning process has determined that the driver's accelerator operation characteristic is the third characteristic (the counter value N1 has reached the threshold C), the condition for setting the engine start flag Fg2 is not met at time t1, and the internal combustion engine 11 is not started.

[0098] Next, when the accelerator opening Acc falls below a predetermined opening threshold A at time t2, the second timer counter starts measuring the duration T2. ​​In the example of FIG. 6, where the learning process has not determined that the driver's accelerator operation characteristic is the third characteristic (counter value N1 has not reached threshold C), the engine start flag Fg2, which is in the ON state, is cleared. However, because the accelerator opening Acc has not become zero, the operation of the internal combustion engine 11 continues.

[0099] Next, at time t3, when the standby time T1 reaches the first time E while the accelerator pedal position Acc is less than the predetermined opening threshold A, the standby time T1 is returned to zero. Furthermore, at time t4, when the duration T2 reaches the second time F while the accelerator pedal position Acc is less than the predetermined opening threshold A, the start suppression mode flag Fg1 is cleared and the counter value N2 is counted up. Next, when the accelerator pedal position Acc becomes zero at time t5, in the example of FIG. 6, the operation of the internal combustion engine 11 is stopped.

[0100] Next, when the accelerator opening Acc reaches the predetermined opening threshold A at time t6, similarly to time t1, the start suppression mode flag Fg1 is set, and the first timer counter starts measuring the standby time T1. In the example of FIG. 6, where the learning process has not determined that the driver's accelerator operation characteristic is the third characteristic (the counter value N1 has not reached the threshold C), the engine start flag Fg2 is set at time t6, and the internal combustion engine 11 is started (the engine speed Ne increases). Accordingly, the counter value N1, which measures the number of times the internal combustion engine 11 has been started due to the accelerator opening Acc, is counted up. On the other hand, in the example of FIG. 7, where the learning process has determined that the driver's accelerator operation characteristic is the third characteristic (the counter value N1 has reached the threshold C), the condition for setting the engine start flag Fg2 is not met at time t6, and therefore the internal combustion engine 11 is not started.

[0101] Next, when the accelerator opening Acc falls below the predetermined opening threshold A at time t7, the second timer counter starts measuring the duration T2, as at time t2. In the example of FIG. 6, where the learning process has not determined that the driver's accelerator operation characteristic is the third characteristic (counter value N1 has not reached threshold C), the engine start flag Fg2, which is in the ON state, is cleared. However, because the accelerator opening Acc has not become zero, the operation of the internal combustion engine 11 continues.

[0102] Next, at time t8, when the accelerator opening Acc is less than the predetermined opening threshold A and the standby time T1 reaches the first time E, the standby time T1 is returned to zero, similar to time t3.

[0103] Next, at time t9, if the accelerator opening Acc again reaches the predetermined opening threshold A before the duration T2 reaches the second time F, the duration T2 is returned to zero, the start suppression mode flag Fg1 is cleared, and the engine start flag Fg2 is set. In the example of FIG. 6, where the learning process has not determined that the driver's accelerator operation characteristic is the third characteristic (the counter value N1 has not reached the threshold C), the internal combustion engine 11 is already in an operating state, so operation of the internal combustion engine 11 continues. On the other hand, in the example of FIG. 7, where the learning process has determined that the driver's accelerator operation characteristic is the third characteristic (the counter value N1 has reached the threshold C), the internal combustion engine 11 is started (the engine speed Ne increases). Accordingly, the counter value N1, which measures the number of times the internal combustion engine 11 has been started due to the accelerator opening Acc, is counted up.

[0104] Next, when the accelerator pedal position Acc falls below the predetermined position threshold A again at time t10, the engine start flag Fg2 is cleared. However, because the accelerator pedal position Acc has not become zero, the operation of the internal combustion engine 11 continues in both the examples of Figures 6 and 7. Thereafter, when the accelerator pedal position Acc becomes zero at time t11, the operation of the internal combustion engine 11 is stopped in both the examples of Figures 6 and 7.

[0105] Next, when the accelerator opening Acc reaches the predetermined opening threshold A at time t12, the start suppression mode flag Fg1 is set, and the first timer counter starts measuring the standby time T1, just as at time t1. In the example of FIG. 6, where the learning process has not determined that the driver's accelerator operation characteristic is the third characteristic (the counter value N1 has not reached the threshold C), the engine start flag Fg2 is set at time t12, and the internal combustion engine 11 is started (the engine speed Ne increases). Accordingly, the counter value N1, which measures the number of times the internal combustion engine 11 has been started due to the accelerator opening Acc, is counted up. On the other hand, in the example of FIG. 7, where the learning process has determined that the driver's accelerator operation characteristic is the third characteristic (the counter value N1 has reached the threshold C), the condition for setting the engine start flag Fg2 is not met at time t12, and the internal combustion engine 11 is not started.

[0106] Next, at time t13, when the standby time T1 reaches the first time E while the accelerator opening Acc is equal to or greater than the predetermined opening threshold A, the standby time T1 is returned to zero, and the start suppression mode flag Fg1 is cleared. In the example of FIG. 6, where the learning process has not determined that the driver's accelerator operation characteristic is the third characteristic (the counter value N1 has not reached the threshold C), the internal combustion engine 11 is already in an operating state, so the operation of the internal combustion engine 11 continues (the engine speed Ne increases). Furthermore, the engine start flag Fg2 is maintained in the ON state. On the other hand, in the example of FIG. 7, where the learning process has determined that the driver's accelerator operation characteristic is the third characteristic (the counter value N1 has reached the threshold C), the engine start flag Fg2 is set, and the internal combustion engine 11 is started (the engine speed Ne increases). Accordingly, the counter value N1, which measures the number of times the internal combustion engine 11 has been started due to the accelerator opening Acc, is counted up.

[0107] Next, when the accelerator pedal position Acc falls below the predetermined position threshold A again at time t14, the engine start flag Fg2 is cleared in both the examples of Figures 6 and 7. However, because the accelerator pedal position Acc has not become zero, the operation of the internal combustion engine 11 continues in both the examples of Figures 6 and 7.

[0108] In Figure 7, the engine speed Ne in the example of Figure 6 in which the driver's accelerator operation characteristic is not determined to have the third characteristic is shown by a dashed line. As is clear from a comparison of the engine speed Ne (solid line) when the driver's accelerator operation characteristic is determined to have the third characteristic with the engine speed Ne (dashed line) when the driver's accelerator operation characteristic is not determined to have the third characteristic, the technology of the present disclosure can reduce the number of times the internal combustion engine 11 is started when a driver with the third characteristic starts the vehicle 1. In particular, it can prevent the internal combustion engine 11 from starting when the driver does not intend to rapidly increase torque when depressing the accelerator pedal after time t1.

[0109] Furthermore, when the accelerator pedal is depressed after time t6 and after time t12, it is possible to determine that the driver intends to rapidly increase torque, and to prevent the internal combustion engine 11 from failing to start.

[0110] Although the preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings, the present disclosure is not limited to such examples. It is clear that a person skilled in the art to which the present disclosure pertains can conceive of various modifications or alterations within the scope of the technical ideas set forth in the claims, and it is understood that these also naturally fall within the technical scope of the present disclosure.

[0111] For example, in the above embodiment, all of the functions of the control device 60 are installed in the vehicle 1, but the technology of the present disclosure is not limited to this example. Some or all of the functions of the control device 60 may be configured by an external server connected to the vehicle 1 so as to be able to communicate with the vehicle 1. [Explanation of symbols]

[0112] 1: vehicle, 11: internal combustion engine, 13: drive motor, 15: transmission, 17: battery, 19: inverter, 21: wheels, 23: crankshaft, 25: motor rotating shaft, 30: transmission mechanism, 51: engine speed sensor, 53: output speed sensor, 55: accelerator sensor, 60: control device, 61: processing unit, 63: memory unit, 71: accelerator opening determination unit, 73: engine start / stop determination unit, 75: learning unit, 77: required drive torque calculation unit, 79: internal combustion engine control unit, 81: motor control unit

Claims

1. 1. A start control device for controlling the start of an internal combustion engine in a hybrid vehicle having a drive motor and an internal combustion engine as drive power sources for the vehicle, comprising: one or more processors; and one or more memories communicatively coupled to the one or more processors; the one or more processors: an engine start / stop determination process that generates a stop request for the internal combustion engine when an accelerator opening by the driver is less than a predetermined opening threshold, and generates a start request for the internal combustion engine when the accelerator opening by the driver is equal to or greater than the predetermined opening threshold; a learning process for learning an accelerator operation characteristic, which is the ratio of the number of times the accelerator opening becomes equal to or greater than the predetermined opening threshold within a predetermined time threshold, to the number of times the accelerator opening becomes equal to or greater than the predetermined opening threshold when the vehicle is started or accelerated; an internal combustion engine starting process that, after a start request for the internal combustion engine is generated, executes a first starting process to start the internal combustion engine when the accelerator opening becomes equal to or greater than the predetermined opening threshold if the ratio is less than a predetermined ratio threshold based on a learning result of the accelerator operation characteristic, and executes a second starting process to start the internal combustion engine after the accelerator opening has remained equal to or greater than the predetermined opening threshold for a predetermined period of time if the ratio is equal to or greater than the predetermined ratio threshold; A starting control device for an internal combustion engine that performs the above.

2. the one or more processors: In the second start-up process, when a start request for the internal combustion engine is generated, a start-up suppression mode is set, when a predetermined first time has elapsed since the generation of the start request for the internal combustion engine without the accelerator opening becoming less than the predetermined opening threshold value, When the accelerator opening degree again becomes less than the predetermined opening degree threshold before the predetermined first time has elapsed since the generation of the start request for the internal combustion engine, and then a predetermined second time has elapsed without the accelerator opening degree again becoming equal to or greater than the predetermined opening degree threshold; and When the accelerator opening degree again becomes less than the predetermined opening degree threshold before the predetermined first time has elapsed since the generation of the start request for the internal combustion engine, and then the accelerator opening degree again becomes equal to or greater than the predetermined opening degree threshold before the predetermined second time has elapsed, When any one of the conditions is satisfied, the setting of the start suppression mode is cancelled, 2. The internal combustion engine start control device according to claim 1, wherein the internal combustion engine is started when the start suppression mode is released in a state where the accelerator opening is equal to or greater than the predetermined opening threshold.

3. 1. A computer program applied to a start control device for controlling the start of an internal combustion engine in a hybrid vehicle having a drive motor and an internal combustion engine as drive power sources for the vehicle, comprising: one or more processors, an engine start / stop determination process that generates a stop request for the internal combustion engine when an accelerator opening by the driver is less than a predetermined opening threshold, and generates a start request for the internal combustion engine when the accelerator opening by the driver is equal to or greater than the predetermined opening threshold; a learning process for learning an accelerator operation characteristic, which is the ratio of the number of times the accelerator opening becomes equal to or greater than the predetermined opening threshold within a predetermined time threshold, to the number of times the accelerator opening becomes equal to or greater than the predetermined opening threshold when the vehicle is started or accelerated; an internal combustion engine starting process that, after a start request for the internal combustion engine is generated, executes a first starting process to start the internal combustion engine when the accelerator opening becomes equal to or greater than the predetermined opening threshold if the ratio is less than a predetermined ratio threshold based on a learning result of the accelerator operation characteristic, and executes a second starting process to start the internal combustion engine after the accelerator opening has remained equal to or greater than the predetermined opening threshold for a predetermined period of time if the ratio is equal to or greater than the predetermined ratio threshold; A computer program that executes

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