Patent Publication Number: US-2023138881-A1

Title: Vehicle controller and vehicle control method

Description:
1. FIELD 
     The present disclosure relates to a vehicle controller and a vehicle control method. 
     2. DESCRIPTION OF RELATED ART 
     A vehicle disclosed in Japanese Laid-Open Patent Publication No. 9-189251 includes an internal combustion engine, an alternator, a battery, electric devices, and a controller. The alternator generates electric power based on the driving force of the internal combustion engine. The battery is charged with the electric power generated by the alternator. The electric devices use the electric power supplied from the battery. The controller determines whether the electric power stored in the battery is lower than a predetermined reference determination value. The controller increases the idle rotation speed of the internal combustion engine when the electric power stored in the battery is lower than the reference determination value. 
     In the vehicle disclosed in the above publication, the idling rotation speed of the internal combustion engine is changed regardless of whether the occupant of the vehicle turns on or off the electric devices and operates the accelerator pedal. If the idle rotation speed is changed regardless of various operations by the occupant, the occupant may feel uncomfortable. 
     SUMMARY 
     This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. 
     A controller for a vehicle according to an aspect of the present disclosure is provided. The vehicle includes an internal combustion engine, a generator configured to generate electric power based on a driving force of the internal combustion engine, a battery configured to be charged with the electric power generated by the generator, and electric devices configured to use the electric power supplied from the battery and configured to be switched on and off by an occupant of the vehicle. The electric devices are divided into groups according to a magnitude of electric power used by each of the electric devices. The number of the groups is smaller than the number of the electric devices. The controller includes circuitry. The circuitry stores in advance different correction amounts respectively associated with the groups. The circuitry is configured to, when the number of operating ones of the electric devices belonging to the same group is equal to or greater than a predetermined specified number, perform an increase process of increasing an engine rotation speed of the internal combustion engine by the correction amount associated with the group in which the number of the operating ones of the electric devices is equal to or greater than the specified number. 
     A control method for a vehicle according to another aspect of the present disclosure is provided. The vehicle includes an internal combustion engine, a generator configured to generate electric power based on a driving force of the internal combustion engine, a battery configured to be charged with the electric power generated by the generator, and electric devices configured to use the electric power supplied from the battery and configured to be switched on and off by an occupant of the vehicle. The control method includes dividing the electric devices into groups according to a magnitude of electric power used by each of the electric devices, the number of the groups being smaller than the number of the electric devices, associating different correction amounts with the groups, respectively, and performing, when the number of operating ones of the electric devices belonging to the same group is equal to or greater than a predetermined specified number, an increase process of increasing an engine rotation speed of the internal combustion engine by the correction amount associated with the group in which the number of the operating ones of electric devices is equal to or greater than the specified number. 
     Other features and aspects will be apparent from the following detailed description, the drawings, and the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic diagram showing a schematic configuration of a vehicle. 
         FIG.  2    is a flowchart showing an increase control. 
     
    
    
     Throughout the drawings and the detailed description, the same reference numerals refer to the same elements. The drawings may not be to scale, and the relative size, proportions, and depiction of elements in the drawings may be exaggerated for clarity, illustration, and convenience. 
     DETAILED DESCRIPTION 
     This description provides a comprehensive understanding of the methods, apparatuses, and/or systems described. Modifications and equivalents of the methods, apparatuses, and/or systems described are apparent to one of ordinary skill in the art. Sequences of operations are exemplary, and may be changed as apparent to one of ordinary skill in the art, with the exception of operations necessarily occurring in a certain order. Descriptions of functions and constructions that are well known to one of ordinary skill in the art may be omitted. 
     Exemplary embodiments may have different forms, and are not limited to the examples described. However, the examples described are thorough and complete, and convey the full scope of the disclosure to one of ordinary skill in the art. 
     In this specification, “at least one of A and B” should be understood to mean “only A, only B, or both A and B.” 
     Schematic Configuration of Vehicle 
     An embodiment will be described below with reference to  FIGS.  1  and  2   . First, a schematic configuration of a vehicle  100  will be described. 
     As shown in  FIG.  1   , the vehicle  100  includes an internal combustion engine  10 , a torque converter  20 , an automatic transmission  30 , a differential  41 , and drive wheels  42 . 
     The internal combustion engine  10  has a crankshaft  11 . A mixture of fuel and intake air is combusted in a cylinder (not shown), thereby rotating the crankshaft  11 . A first end of the crankshaft  11  is connected to left and right drive wheels  42  via the torque converter  20 , the automatic transmission  30 , and the differential  41 . The torque converter  20  converts the torque input from the crankshaft  11  and outputs it. The automatic transmission  30  selects one of gear stages according to the driving state of the vehicle  100 . The automatic transmission  30  changes the torque input from the torque converter  20  at a ratio corresponding to the selected gear stage and outputs the changed torque. The differential  41  allows the left and right drive wheels  42  to have different rotation speeds. Thus, the vehicle  100  can travel with the driving force of the internal combustion engine  10 . 
     The vehicle  100  includes a belt  50 , an alternator  51 , and a battery  52 . The alternator  51  is connected to a second end of the crankshaft  11  via the belt  50 . Therefore, the alternator  51  can generate electric power based on the driving force of the internal combustion engine  10 . The electric power generated by the alternator  51  increases as an engine rotation speed NE, which is the rotation speed of the crankshaft  11 , increases. In this embodiment, the alternator  51  is an example of a generator. The battery  52  is electrically connected to the alternator  51 . The battery  52  is charged with electric power generated by the alternator  51 . 
     The vehicle  100  includes electric devices, namely, a rear defogger  61 , a tail lamp  62 , an entire surface deicer  63 , and a seat heater  64 . The rear defogger  61  is attached to a portion of the rear window glass of the vehicle  100 . The rear defogger  61  has a heating wire (not shown), and heats the rear window glass when the heating wire is energized. The tail lamp  62  is attached to the rear of vehicle  100 . The tail lamp  62  is lit by being energized. The entire surface deicer  63  is attached to the entire windshield of the vehicle  100 . The entire surface deicer  63  has a heating wire (not shown), and heats the windshield when the heating wire is energized. The seat heater  64  is attached to the seat of the vehicle  100 . The seat heater  64  includes a heating wire (not shown), and heats the seat when the heating wire is energized. The rear defogger  61 , the tail lamp  62 , the entire surface deicer  63 , and the seat heater  64  are operated using electric power supplied from the battery  52 . 
     The electric power used by each of the rear defogger  61  and the tail lamp  62  is less than a predetermined threshold. That is, the rear defogger  61  and the tail lamp  62  belong to a first group, which is a group whose electric power used is less than the threshold. The electric power used by each of the entire surface deicer  63  and the seat heater  64  is equal to or greater than the threshold. That is, the entire surface deicer  63  and the seat heater  64  belong to a second group, which is a group whose electric power used is equal to or greater than the threshold. Accordingly, the rear defogger  61 , the tail lamp  62 , the entire surface deicer  63 , and the seat heater  64  are divided into two groups according to the amount of electric power used. The number of the groups is less than four, which is the number of the electric devices. An example of the threshold is  10  A/sec. 
     The vehicle  100  includes an accelerator operation sensor  71 , a vehicle speed sensor  72 , and a crank angle sensor  73 . The accelerator operation sensor  71  detects an accelerator operation amount ACC, which is an operation amount of an accelerator pedal operated by the driver of the vehicle  100 . The larger the amount of operation of the accelerator pedal by the driver of the vehicle  100 , the larger the value of the accelerator operation amount ACC. When the driver of the vehicle  100  does not operate the accelerator pedal, the accelerator operation amount ACC is zero. The vehicle speed sensor  72  detects a vehicle speed SP, which is the traveling speed of the vehicle  100 . The crank angle sensor  73  is arranged near the crankshaft  11 . The crank angle sensor  73  detects a crank angle SC, which is the angular position of the crankshaft  11 . 
     The vehicle  100  includes a controller  90 . The controller  90  acquires a signal indicating the accelerator operation amount ACC from the accelerator operation sensor  71 . The controller  90  acquires a signal indicating the vehicle speed SP from the vehicle speed sensor  72 . The controller  90  acquires a signal indicating the crank angle SC from the crank angle sensor  73 . The controller  90  calculates the engine rotation speed NE, which is the rotation speed of the crankshaft  11 , based on the crank angle SC. 
     Based on the accelerator operation amount ACC and the vehicle speed SP, the controller  90  calculates a vehicle required output, which is a required value of the output required for the vehicle  100  to travel. The controller  90  controls the internal combustion engine  10  by outputting a control signal, which is based on the vehicle required output, to the internal combustion engine  10 . 
     The controller  90  switches the rear defogger  61 , the tail lamp  62 , the entire surface deicer  63 , and the seat heater  64  on and off. Specifically, the controller  90  switches the rear defogger  61  on and off according to the operation of a switch (not shown) for the rear defogger  61  by the occupant of the vehicle  100 . The controller  90  switches the tail lamp  62  on and off according to the operation of a switch (not shown) for the tail lamp  62  by the occupant of the vehicle  100 . The controller  90  switches the entire surface deicer  63  on and off according to the operation of a switch (not shown) for the entire surface deicer  63  by the occupant of the vehicle  100 . The controller  90  switches the seat heater  64  on and off according to the operation of a switch (not shown) for the seat heater  64  by the occupant of the vehicle  100 . 
     The controller  90  stores in advance a first correction amount B  1 , which is a correction amount corresponding to the first group, and a second correction amount B 2 , which is a correction amount corresponding to the second group, to perform an increase control (described later). Details of the first correction amount B 1  and the second correction amount B 2  will be described later. 
     The controller  90  may include circuitry having one or more processors that execute various processes according to a computer program (software). The controller  90  may include circuitry having one or more dedicated hardware circuits, such as an application specific integrated circuit (ASIC), that perform at least some of the various processes. The controller  90  may include circuitry having a combination of the one or more processors and the one or more dedicated hardware circuits. The processor includes a CPU and a memory such as a RAM and a ROM. The memory stores program codes or instructions configured to cause the CPU to perform processes. The memory, or a computer-readable medium, includes any media that can be accessed by a general purpose or special purpose computer. 
     Among the above devices, the rear defogger  61 , the tail lamp  62 , the entire surface deicer  63 , and the seat heater  64  are electric devices that can be turned on and off by the occupant of the vehicle  100 . The controller  90 , the accelerator operation sensor  71 , the vehicle speed sensor  72 , and the crank angle sensor  73  are electric devices that are maintained at an ON state as long as the vehicle  100  is driven. That is, these devices  90 ,  71 ,  72 , and  73  are electric devices that cannot be turned on and off by the occupant of the vehicle  100  while the vehicle  100  is being driven. 
     Increase Control 
     Next, the increase control performed by the controller  90  will be described. The controller  90  repeatedly executes the increase control from when the internal combustion engine  10  starts to when the internal combustion engine  10  stops. 
     As shown in  FIG.  2   , after starting the increase control, the controller  90  advances the process to step S 11 . In step S 11 , the controller  90  determines whether the internal combustion engine  10  is idling. Specifically, the controller  90  determines that the internal combustion engine  10  is idling when the accelerator operation amount ACC is zero and the vehicle speed SP is equal to or lower than a specified vehicle speed. The specified vehicle speed is predetermined to, for example, a value within the range of  0  to  5  km/h. When the controller  90  determines in step S 11  that the internal combustion engine  10  is not idling (S 11 : NO), the controller  90  ends the current increase control and advances the process to step S 11  again. When the controller  90  determines in step S 11  that the internal combustion engine  10  is idling (S 11 : YES), the controller  90  advances the process to step S 21 . 
     In step S 21 , the controller  90  determines whether the electric device is operating. Specifically, the controller  90  determines that the electric device is operating when one or more of the rear defogger  61 , the tail lamp  62 , the entire surface deicer  63 , and the seat heater  64  are operating. When the controller  90  determines in step S 21  that no electric device is operating (S 21 : NO), the controller  90  advances the process to step S 51 . 
     In step S 51 , the controller  90  sets, to a predetermined initial value A, a target value of the engine rotation speed NE when the internal combustion engine  10  is idling. An example of the initial value A is several hundred rpm. After that, the controller  90  ends the current increase control and advances the process to step S 11  again. 
     When determining in step S 21  that the electric device is operating (S 21 : YES), the controller  90  advances the process to step S 22 . 
     In step S 22 , the controller  90  determines whether the electric device belonging to the second group is operating. Specifically, when at least one of the entire surface deicer  63  and the seat heater  64  belonging to the second group is operating, the controller  90  determines that the electric device belonging to the second group is operating. Therefore, in this embodiment, the specified number is  1 . When the controller  90  determines in step S 22  that the electric device belonging to the second group is not operating (S 22 : NO), the process is advanced to step S 41 . That is, if one or more electric devices belonging to the first group are operating and none of the electric devices belonging to the second group are operating, the controller  90  advances the process to step S 41 . 
     In step S 41 , the controller  90  sets, to a value obtained by adding to the initial value A the first correction amount B  1 , which is a correction amount corresponding to the first group, the target value of the engine rotation speed NE when the engine  10  is idling. As a result, the engine rotation speed NE is increased as compared with the case where the initial value A is set without any change. That is, the process of step S 41  is an example of the increase process. The first correction amount B 1  is defined as follows, for example. First, the total value of electric power used by all the electric devices belonging to the first group, that is, the rear defogger  61  and the tail lamp  62 , is obtained through experiments or the like. Further, the minimum value of the engine rotation speed NE required for generating the above total value by the alternator  51  is obtained through experiments or the like. The first correction amount B 1  is set to a value obtained by subtracting the initial value A from the minimum value of the required engine rotation speed NE. Therefore, the first correction amount B 1  is set to a value that allows the alternator  51  to generate electric power equal to or greater than the total value of the electric power used by all the electric devices belonging to the first group. In step S 41 , the controller  90  does not change the engine rotation speed NE based on the second correction amount B 2 . After that, the controller  90  ends the current increase control and advances the process to step S 11  again. 
     When the controller  90  determines in step S 22  that the electric device belonging to the second group is operating (S 22 : YES), the process is advanced to step S 31 . 
     In step S 31 , the controller  90  sets, to a value obtained by adding to the initial value A the second correction amount B 2 , which is a correction amount corresponding to the second group, the target value of the engine rotation speed NE when the engine  10  is idling. As a result, the engine rotation speed NE is increased as compared with the case where the initial value A is set without any change. That is, the process of step S 31  is an example of the increase process. The second correction amount B 2  is defined as follows, for example. First, the total value of the electric power used by all the electric devices belonging to the second group, i.e., the entire surface deicer  63  and the seat heater  64 , is obtained through experiments or the like. Further, the minimum value of the engine rotation speed NE required for generating the above total value by the alternator  51  is obtained through experiments or the like. The second correction amount B 2  is set to a value obtained by subtracting the initial value A from the minimum value of the required engine rotation speed NE. Therefore, the second correction amount B 2  is set to a value that allows the alternator  51  to generate electric power equal to or greater than the total value of the electric power used by all the electric devices belonging to the second group. In this embodiment, the second correction amount B 2  is larger than the first correction amount B 1 . That is, the first correction amount B 1  and the second correction amount B 2  are different from each other. 
     In step S 31 , the controller  90  does not change the engine rotation speed NE based on the first correction amount B  1 . That is, even when the controller  90  determines that the electric devices belonging to the second group are operating and the electric devices belonging to the first group are operating, the controller  90  does not change the engine rotation speed NE based on the first correction amount B  1 . In other words, when the controller  90  determines that the electric devices belonging to the second group are operating, the controller  90  increases the engine rotation speed NE based only on the second correction amount B 2  without changing the engine rotation speed NE based on the first correction amount B 1  regardless of whether the electric devices belonging to the first group are operating. After that, the controller  90  ends the current increase control and advances the process to step S 11  again. 
     Effect of Embodiment 
     For example, it is assumed that the internal combustion engine  10  is idling and the rear defogger  61 , the tail lamp  62 , the entire surface deicer  63 , and the seat heater  64  are not operating. At this time, the engine rotation speed NE is constant at the initial value A. After that, it is assumed that the entire surface deicer  63  of the electric devices starts to be operated through an ON operation of the switch by the occupant of the vehicle  100 . In this case, if the engine rotation speed NE is kept constant, the electric power supplied from the battery  52  to the entire surface deicer  63  may run short, or the electric power of the battery  52  may decrease. To solve this problem, the electric power generated by the alternator  51  is increased by increasing the engine rotation speed NE. Specifically, the controller  90  sets the target value of the engine rotation speed NE to the value obtained by adding the second correction amount B 2  to the initial value A. 
     It is assumed that the rear defogger  61  starts to be operated by the occupant of the vehicle  100  turning on the switch while the rear defogger  61 , the tail lamp  62 , the entire surface deicer  63 , and the seat heater  64  are not operating. In this case, the controller  90  sets the target value of the engine rotation speed NE to the value obtained by adding the first correction amount B 1  to the initial value A. 
     Advantages of Embodiment 
     (1) In the present embodiment, when the entire surface deicer  63  is operated by the occupant of the vehicle  100  operating the switch, the engine rotation speed NE is controlled to a value obtained by adding the second correction amount B 2  to the initial value A. That is, the engine rotation speed NE changes at the point in time when the switch is turned on and off by the occupant of the vehicle  100 . The engine rotation speed NE is prevented from changing independently of the ON/OFF operation of the switch by the occupant of the vehicle  100 . This prevents the occupant from feeling uncomfortable due to a change in the engine rotation speed NE without the occupant&#39;s operation. 
     ( 2 ) It is assumed that the engine rotation speed NE is changed each time the operating conditions of the rear defogger  61 , the tail lamp  62 , the entire surface deicer  63 , and the seat heater  64  change. In this case, the occupant of the vehicle  100  may feel uncomfortable as the engine rotation speed NE changes frequently. 
     In the present embodiment, the rear defogger  61 , the tail lamp  62 , the entire surface deicer  63 , and the seat heater  64  are divided into two groups according to the amount of electric power used. The number of the groups is less than four, which is the number of the electric devices. The engine rotation speed NE is changed for the state of each group corresponding to the number of electric devices that are operating in the group. This prevents the engine rotation speed NE from changing each time the operating states of the electric devices change. That is, the occupant of the vehicle  100  is prevented from feeling uncomfortable due to frequent changes in the engine rotation speed NE. 
     (3) In the present embodiment, the second correction amount B 2  is larger than the first correction amount B 1 . Therefore, the engine rotation speed NE can be adjusted according to whether the electric power used by the electric devices belonging to each group is large or small. 
     (4) In the present embodiment, there are two groups for changing the engine rotation speed NE. Therefore, compared to the case where the number of groups is, for example, three or more, the engine rotation speed NE is not frequently changed. 
     (5) In the present embodiment, when the number of operating ones of the electric devices belonging to the second group is one or more, the controller  90  increases the engine rotation speed NE based only on the second correction amount B 2  without changing the engine rotation speed NE based on the first correction amount B 1 . When the number of operating ones of the electric devices belonging to the second group is zero and the number of operating ones of the electric devices belonging to the first group is one or more, the controller  90  does not change the engine rotation speed NE based on the second correction amount B 2 . In this case, the controller  90  increases the engine rotation speed NE based only on the first correction amount B  1 . Therefore, the engine rotation speed NE is adjusted to one of three patterns of values: a value that remains the initial value A to which neither the first correction amount B 1  nor the second correction amount B 2  is added; a value obtained by adding only the first correction amount B 1  to the initial value A; and a value obtained by adding only the second correction amount B 2  to the initial value A. Adjustment of the engine rotation speed NE in such three patterns reduces the possibility that the occupant of the vehicle  100  feels uncomfortable. Also, the electric power used by the electric devices belonging to the first group is smaller than the electric power used by the electric devices belonging to the second group. Therefore, for example, even when only one or more electric devices belonging to the second group were operating and then one or more electric devices belonging to the first group start operating, the engine rotation speed NE has already been increased based on the second correction amount B 2 . Thus, the possibility that the electric power of the battery  52  becomes insufficient is low. 
     (6) In the present embodiment, the first correction amount B 1  is set to a value that allows the alternator  51  to generate electric power equal to or greater than the total value of the electric power used by all the electric devices belonging to the first group. Also, the second correction amount B 2  is set to a value that allows the alternator  51  to generate electric power equal to or greater than the total value of the electric power used by all the electric devices belonging to the second group. Therefore, even when all the electric devices belonging to each group are in operation, the alternator  51  can generate a sufficient amount of electric power. As a result, if electric devices belong to the same group, a change in the number of operating ones of the electric devices does not necessitate a change in the engine rotation speed NE in order to generate a sufficient amount of electric power. 
     (7) In the present embodiment, the increase processes in steps S 31  and S 41  are performed on the condition that the accelerator operation amount ACC is zero and the vehicle speed SP is equal to or less than the specified vehicle speed. In other words, the engine rotation speed NE is increased in a situation in which the sound caused by the traveling of the vehicle  100  is less likely to occur and the occupant of the vehicle  100  is more likely to perceive the sound caused by a change in the engine rotation speed NE. It is particularly preferable to apply the above technology relating to the increase process under a situation in which a change in the engine rotation speed NE is likely to be perceived by the occupant as a change in sound. 
     Modified Examples 
     The present embodiment can be implemented with the following modifications. The present embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range. 
     In the above embodiment, the type of electric device may be changed. 
     For example, the vehicle  100  may include an inverter that converts the DC power of battery  52  to AC power, and an outlet for that AC power. In this vehicle  100 , when the inverter is operated, AC power can be supplied from the outlet to an external device. In such a vehicle  100 , an external device is connected to the outlet through the operation of the occupant, and the inverter outputs electric power accordingly. Therefore, the inverter corresponds to the electric device that can be switched on and off by the occupant. In this way, the electric device may be not only an electric device that can be directly switched on and off by the occupant using a switch, but also an electric device that can be indirectly switched on and off. 
     In the above embodiment, the threshold of electric power used for grouping may be changed. 
     For example, the threshold can be changed according to the electric power generation capacity of the alternator  51 , the electric power storage capacity of the battery  52 , and the like. 
     In the above embodiment, the number of electric devices belonging to each group may be changed. 
     For example, depending on the value of the threshold, the electric power used by the tail lamp  62  may be less than the threshold, and the electric power used by the rear defogger  61  may be equal to or greater than the threshold. In this case, the tail lamp  62  belongs to the first group, and the rear defogger  61 , the entire surface deicer  63 , and the seat heater  64  belong to the second group. That is, the number of the electric devices belonging to the first group or the second group may be changed as long as it is one or more. However, the number of electric devices belonging to one of the groups must be plural. 
     In the above embodiment, the number of groups may be changed. 
     For example, a third group may be provided in addition to the first and second groups. That is, the number of groups may be changed as long as it is two or more and less than the number of electric devices. 
     In the above embodiment, the second correction amount B 2  is added to the initial value A if at least one of the electric devices belonging to the second group is operating. Such a configuration may be changed. 
     For example, in step S 22 , the controller  90  may determine that the electric device belonging to the second group is operating when two or more of the entire surface deicer  63  and the seat heater  64  belonging to the second group are operating. That is, the specified number may be changed within a range of one or more and the number of electric devices belonging to the group or less. The same applies to the first group. 
     In the above embodiment, the correction amount may be changed. 
     For example, the second correction amount B 2  may be set to a value that allows the alternator  51  to generate electric power equal to or greater than the total electric power used by all the electric devices belonging to the first group and the second group. 
     Further, for example, the second correction amount B 2  may be set to a value that allows the alternator  51  to generate the electric power used only by the full-surface deicer  63  belonging to the second group. Similarly, the first correction amount B 1  may be set to a value that allows the alternator  51  to generate the electric power used only by the rear defogger  61  belonging to the first group. 
     In the above embodiment, the conditions for using the correction amounts may be changed. 
     For example, when the controller  90  determines that the electric device belonging to the second group is operating and the electric device belonging to the first group is operating, both the first correction amount B 1  and the second correction amount B 2  may be used. Specifically, the controller  90  may set, to a value obtained by adding the first correction amount B 1  and the second correction amount B 2  to the initial value A, the target value of the engine rotation speed NE when the engine  10  is idling. 
     The initial value A in the above embodiment is not limited to a fixed value, and may be a variable value. Even when the internal combustion engine  10  is idling, the target value of the engine rotation speed NE changes depending on, for example, the amount of electric power stored in the battery  52  and the temperature of the internal combustion engine  10 . Therefore, the initial value A may be a variable value determined according to various parameters of the vehicle  100  other than whether the electric device is operating. In this case, as long as the initial value A is obtained based on a predetermined map and relational equation, that value is a predetermined one. 
     In the above embodiment, the conditions for executing the increase process may be changed. 
     For example, the specified vehicle speed in step S 11  may exceed  5  km/h. 
     Further, for example, the process of step S 11  may be omitted. In other words, the controller  90  may execute the processes after step S 21  not only during idling. The initial value A in this modified example is a variable value that varies according to the accelerator operation amount ACC and the like. 
     In the above embodiment, the configuration of the vehicle  100  may be changed. 
     For example, the vehicle  100  may include a motor generator as a drive source. In this configuration, if the motor generator is connected to the crankshaft  11  of the internal combustion engine  10  and can generate electric power based on the driving force of the internal combustion engine  10 , the motor generator may correspond to the generator. In this case, the alternator  51  may be omitted. 
     Various changes in form and details may be made to the examples above without departing from the spirit and scope of the claims and their equivalents. The examples are for the sake of description only, and not for purposes of limitation. Descriptions of features in each example are to be considered as being applicable to similar features or aspects in other examples. Suitable results may be achieved if sequences are performed in a different order, and/or if components in a described system, architecture, device, or circuit are combined differently, and/or replaced or supplemented by other components or their equivalents. The scope of the disclosure is not defined by the detailed description, but by the claims and their equivalents. All variations within the scope of the claims and their equivalents are included in the disclosure.