Control device for vehicle

Abstract

To provide a control device for a vehicle capable of preventing a driver from feeling uncomfortable due to mismatch of display of a battery charging state and display on automatic stop of an engine.SOLUTION: During traveling of a vehicle, an ECU executes charging state display control for displaying a charging state of a lithium ion battery on a display device. During stop of the vehicle, when automatic stop of an engine is not executed because the charging state of the lithium ion battery is a predetermined charging state or greater but a charging state of a lead battery is smaller than the predetermined charging state and when it is determined that a driver can afford to visually recognize the charging state of the lithium ion battery on the display device in a deceleration period on the basis of a brake stroke amount in the deceleration period during traveling of the vehicle immediately before the vehicle stop, the ECU performs non-display control for preventing display on the display device of the reason why the automatic stop of the engine is not performed (Step S6).SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a vehicle control device. [Background technology]

[0002] A known conventional vehicle control device is described in Patent Document 1. Patent Document 1 describes a vehicle equipped with a multi-information display. The multi-information display is a display device that displays multiple pieces of information such as the vehicle's energy flow, average fuel economy, and information related to idling stop. In a vehicle with an idling stop function, the multi-information display displays the energy flow including the battery charge state while the vehicle is traveling, and switches to displaying various information related to idling stop while the engine is stopped due to idling stop. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-246844 Summary of the Invention [Problem to be solved by the invention]

[0004] Meanwhile, vehicles equipped with an idle stop function may be equipped with two types of batteries, such as a lithium-ion battery and a lead battery. In such vehicles, the lithium-ion battery is used as a power source for auxiliary equipment when the engine is stopped, and the lead battery is used as a power source for auxiliary equipment when the engine is running. However, if the auxiliary equipment is under heavy load, a power supply from the lead battery may be required. Therefore, idle stop is generally permitted only when the state of charge of both the lithium-ion battery and the lead battery is sufficiently high.

[0005] Here, the information about the energy flow displayed on the multi-information display includes the state of charge of the lithium-ion battery. Furthermore, the information about idling stop after the engine automatically stops includes the duration of idling stop, etc., but if idling stop cannot be performed, this fact and the reason why it cannot be performed are displayed. For example, if the state of charge of one of the two batteries is low, the reason why idling stop cannot be performed is displayed as the fact that the battery is charging, without specifying which of the two batteries.

[0006] In such a system, the driver recognizes from the display that the lithium-ion battery's state of charge is low, and if the display indicates that the battery is charging as the reason why idling stop cannot be performed, the driver can easily understand that idling stop cannot be performed because the lithium-ion battery with a low state of charge is currently charging. However, because idling stop is permitted when the state of charge of the lithium-ion battery and the lead-acid battery are sufficiently high, if the lithium-ion battery is close to being fully charged but the state of charge of the lead-acid battery is low enough that idling stop cannot be performed, the multi-information display will indicate that the lithium-ion battery is sufficiently charged, but will also indicate that the battery is currently charging as the reason why idling stop cannot be performed, creating a problem in which the driver feels uncomfortable due to the inconsistency between the display of the battery's state of charge and the display regarding automatic engine stop.

[0007] The present invention has been made in response to the above-mentioned problems, and aims to provide a vehicle control device that can prevent the driver from feeling uncomfortable due to a mismatch between the display of the battery charge state and the display regarding the automatic stop of the engine. [Means for solving the problem]

[0008] The present invention provides a vehicle control device mounted on a vehicle including an engine, a first battery that supplies power to accessories while the engine is automatically stopped, a second battery that supplies power to the accessories while the engine is running, a brake stroke sensor that detects a brake stroke amount of a brake operation by a driver, a vehicle speed sensor that detects the vehicle speed, a display device that displays a vehicle state, and an idling stop control unit that automatically stops the engine when predetermined automatic stop conditions are met, including the state of charge of both the first battery and the second battery being equal to or higher than a predetermined state of charge, and restarts the engine when predetermined restart conditions are met, the vehicle control device further comprising a display control unit that controls the display content of the display device, and the display control unit performs charge state display control to display the charge state of the first battery on the display device while the vehicle is running, and when the vehicle is stopped, If the automatic stop of the engine is not implemented because the charge state of the second battery is less than the predetermined charge state, a reason display control is implemented to display that the charge state is less than the predetermined charge state as the reason why the automatic stop of the engine is not implemented, without specifying whether it is the first battery or the second battery.If, when the vehicle is stopped and the automatic stop of the engine is not implemented because the charge state of the first battery is equal to or greater than the predetermined charge state but the charge state of the second battery is less than the predetermined charge state, and based on the brake stroke amount during the deceleration period while the vehicle is traveling immediately before the vehicle is stopped, it is determined that the driver had enough time to visually confirm the charge state of the first battery on the display device during the deceleration period, a non-display control is implemented to not display on the display device the reason why the automatic stop of the engine is not implemented. [Effects of the Invention]

[0009] As described above, according to the present invention, it is possible to provide a vehicle control device that can prevent the driver from feeling uncomfortable due to a mismatch between the display of the battery charge state and the display related to the automatic stop of the engine. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing the configuration of a vehicle equipped with a vehicle control device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a flowchart illustrating the display control operation of the vehicle control device according to the embodiment of the present invention. [Figure 3] FIG. 3 is a timing chart illustrating the transition of display content when the display control operation of the vehicle control device according to the embodiment of the present invention is executed. DETAILED DESCRIPTION OF THE INVENTION

[0011] A vehicle control device according to one embodiment of the present invention is mounted on a vehicle including an engine, a first battery that supplies power to accessories while the engine is automatically stopped, a second battery that supplies power to the accessories while the engine is running, a brake stroke sensor that detects a brake stroke amount of a brake operation by a driver, a vehicle speed sensor that detects the vehicle speed, a display device that displays a vehicle state, and an idling stop control unit that automatically stops the engine when predetermined automatic stop conditions are met, including that the charge states of both the first battery and the second battery are equal to or higher than a predetermined charge state, and restarts the engine when predetermined restart conditions are met, the vehicle control device including a display control unit that controls the display content of the display device, and the display control unit performs charge state display control to display the charge state of the first battery on the display device while the vehicle is running, and and when the vehicle is stopped and the automatic engine stop is not implemented because the state of charge of the first battery or the second battery is less than a predetermined state of charge, the control unit performs reason display control to display that the state of charge is less than the predetermined state of charge as the reason for the automatic engine stop not being implemented, without specifying the first or second battery, and when the vehicle is stopped and the automatic engine stop is not implemented because the state of charge of the first battery is equal to or greater than the predetermined state of charge but the state of charge of the second battery is less than the predetermined state of charge, and when it is determined that the driver had enough time to visually confirm the state of charge of the first battery on the display device during the deceleration period while the vehicle is traveling immediately before the vehicle is stopped, the control unit performs non-display control to not display on the display device the reason for the automatic engine stop not being implemented. This makes it possible for the vehicle control device according to one embodiment of the present invention to prevent the driver from feeling uncomfortable due to a mismatch between the display of the battery state of charge and the display related to the automatic engine stop. [Example]

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vehicle control device according to an embodiment of the present invention will now be described with reference to the accompanying drawings, in which: Figures 1 to 3 are diagrams illustrating a vehicle control device according to an embodiment of the present invention.

[0013] As shown in Fig. 1, a vehicle 1 according to one embodiment of the present invention includes an engine 2 as a drive source, a transmission (denoted as TM in the figure) 4 to which power is transmitted from the engine 2, and drive wheels 5 to which power is transmitted from the transmission 4. In the vehicle 1, the rotation output from a crankshaft 2A of the engine 2 is changed in speed at a gear ratio corresponding to the gear position established by the transmission 4, and is transmitted to the drive wheels 5 via a differential device and a drive shaft (not shown).

[0014] The engine 2 is a four-stroke engine that performs a series of four strokes consisting of an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke, and generates driving force for the vehicle 1 by igniting between the compression stroke and the expansion stroke.

[0015] The vehicle 1 is equipped with accessories 6. The accessories 6 are powered by a lithium-ion battery 16 or a lead battery 17. The accessories 6 include an ISG (Integrated Starter Generator) and an electric water pump (not shown). The ISG is a device that combines a starting device (starter) that starts the engine 2 and a generator (alternator) into one. The electric water pump is a device that circulates coolant for the engine 2 by being powered by electricity.

[0016] The vehicle 1 is equipped with a lithium ion battery 16 that supplies power to the auxiliary equipment 6 while the engine 2 is automatically stopped, and a lead battery 17 that supplies power to the auxiliary equipment 6 while the engine 2 is running. The lithium ion battery 16 and the lead battery 17 are rechargeable secondary batteries that output a voltage of 12 V. The lithium ion battery 16 constitutes the first battery in the present invention, and the lead battery 17 constitutes the second battery in the present invention.

[0017] The vehicle 1 includes an accelerator pedal sensor 12A, a brake stroke sensor 13A, and an ECU (Electronic Control Unit) 11.

[0018] The accelerator pedal sensor 12A is provided on the accelerator pedal 12 and detects the amount of operation of the accelerator pedal 12.

[0019] The brake stroke sensor 13A is provided on the brake pedal 13 and detects the amount of brake operation by the driver as a brake stroke amount. Here, the operation amount of each pedal is the amount of depression by the driver, and the greater the depression amount, the greater the operation amount.

[0020] The vehicle 1 is provided with a vehicle speed sensor 14 that detects the vehicle speed. A detection signal from the vehicle speed sensor 14 is used to determine whether or not the engine 2 should be automatically stopped.

[0021] The vehicle 1 is equipped with a display device 15. The display device 15 is configured as a multi-information display that displays various vehicle conditions, and is provided at the driver's seat.

[0022] The ECU 11 is composed of a computer unit equipped with a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), flash memory, input ports, and output ports, and electrically controls the controlled object.

[0023] The ROM of the ECU 11 stores various control constants, various maps, and the like, as well as a program for causing the computer unit to function as the ECU 11. In the ECU 11, the CPU executes the program stored in the ROM, causing the computer unit to function as the ECU 11.

[0024] The input port of the ECU 11 is electrically connected to the engine 2 and various sensors such as an accelerator pedal sensor 12A, a brake stroke sensor 13A, and a vehicle speed sensor 14.

[0025] Control targets such as the engine 2, the auxiliary equipment 6, the display device 15, the lithium-ion battery 16, and the lead battery 17 are connected to the output ports of the ECU 11. The ECU 11 controls the control targets connected to the output ports based on detection signals from sensors and the like input to the input ports.

[0026] The ECU 11 automatically stops the engine 2 when predetermined automatic stop conditions are met. The ECU 11 also restarts the engine 2 when predetermined restart conditions are met while the engine 2 is automatically stopped. In this way, the ECU 11 performs so-called idle stop control, which automatically stops and restarts the engine 2. The predetermined automatic stop conditions include that the charge states of both the lithium ion battery 16 and the lead battery 17 are equal to or higher than predetermined charge states. The ECU 11 constitutes an idle stop control unit in the present invention.

[0027] The ECU 11 controls the display content of the display device 15. The ECU 11 constitutes a display control unit in the present invention.

[0028] The ECU 11 performs charge state display control while the vehicle is traveling. In the charge state display control, the ECU 11 displays the charge state of the lithium ion battery 16 on the display device 15. In this way, the information displayed on the display device 15 includes the charge state of the lithium ion battery 16 when the charge state display control is performed. In the charge state display control, when the lithium ion battery 16 is fully charged, for example, a picture in which the inside of a symbol representing the lithium ion battery 16 is filled with multiple bars (for example, four bars) is displayed on the display device 15. Furthermore, the information related to the idling stop after the automatic stop of the engine 2 includes the duration of the idling stop, etc.

[0029] In principle, when the vehicle is stopped and automatic stop of the engine 2 is not implemented because the state of charge of the lithium ion battery 16 or the lead battery 17 is less than a predetermined state of charge, the ECU 11 performs reason display control. In the reason display control, the ECU 11 does not identify the lithium ion battery 16 or the lead battery 17, but simply displays that the state of charge is less than the predetermined state of charge as the reason for not automatically stopping the engine 2. In the reason display control, the display device 15 displays, for example, the text "Idling stop not possible (reason: charging)."

[0030] In this situation, if the lithium-ion battery 16 is nearly fully charged while the lead battery 17 is so low that idling stop cannot be performed, and the display device 15 displays that the lithium-ion battery 16 is sufficiently charged while the vehicle is running, and then displays "Idling stop not possible (reason: charging)" when the vehicle is stopped, the driver may feel uncomfortable because the battery is not being charged, even though the battery is sufficiently charged. In other words, in a situation where the display content of the display device 15 does not distinguish between the lithium-ion battery 16 and the lead battery 17, an inconsistency occurs between the display of the battery charge state and the display regarding the automatic stop of the engine 2, causing discomfort to the driver. To address this inconvenience, it is conceivable to display the content of the display device 15 as "Idling stop not possible (reason: lead battery is charging)," but such a display may be impossible due to the limited size of the display area, or the visibility may be reduced due to the detailed display content.

[0031] Therefore, while ECU 11 generally performs reason display control, as an exception, if idling stop is not performed when the vehicle is stopped, only in situations where the driver's braking (driving operation) burden is small while the vehicle is running (while decelerating) immediately before the vehicle is stopped and the driver is presumed to have had enough time to visually confirm that the lithium-ion battery 16 is sufficiently charged while operating the brakes, ECU 11 will simply display "Idling stop not possible" instead of "Idling stop not possible (reason: charging)".

[0032] When the vehicle is stopped and automatic stop of the engine 2 is not performed because the state of charge of the lithium ion battery 16 is equal to or higher than a predetermined state of charge but the state of charge of the lead battery 17 is lower than the predetermined state of charge, and when the ECU 11 determines that the driver had enough time to visually check the state of charge of the lithium ion battery 16 on the display device 15 during the deceleration period based on the brake stroke amount during the deceleration period while the vehicle was traveling immediately before the vehicle stopped, the ECU 11 performs non-display control. In the non-display control, the ECU 11 does not display on the display device 15 the reason why automatic stop of the engine 2 is not performed. In the non-display control, the display device 15 displays, for example, the message "Idling stop is not possible."

[0033] Furthermore, if the average value of the brake stroke amount during the deceleration period is equal to or less than a predetermined value, the ECU 11 determines that the driver had enough time to visually check the state of charge of the lithium ion battery 16 on the display device 15 during the deceleration period.

[0034] Furthermore, if the average value of the brake stroke amount during the deceleration period is greater than a predetermined value, the ECU 11 determines that the driver did not have time to visually check the state of charge of the lithium ion battery 16 on the display device 15.

[0035] In addition, ECU 11 compares the brake stroke amount during the deceleration period with a judgment threshold value that determines whether or not the brake is being pumped, and if the brake stroke amount is continuously greater than the judgment threshold value, it uses a first predetermined value as the predetermined value, and if there is a moment when the brake stroke amount is equal to or less than the judgment threshold value, it uses a second predetermined value that is greater than the first predetermined value as the predetermined value.

[0036] Here, the braking operation includes a normal braking operation in which the brake pedal 13 is gently depressed in one stroke, and a pumping braking operation in which the brake pedal 13 is intermittently depressed in multiple strokes with a force stronger than that of a normal braking operation to prevent the wheels from locking. Let Bp be a determination threshold for determining whether or not a pumping braking operation is occurring, B1 be a first predetermined value, and B2 be a second predetermined value. If a pumping braking operation is not occurring and the brake stroke amount is continuously greater than Bp, the ECU 11 uses B1 as the predetermined value. On the other hand, if a state in which the brake stroke amount is equal to or less than Bp occurs due to a pumping braking operation, the ECU 11 uses B2 as the predetermined value. If the brake stroke amount alternates between being equal to or less than Bp and being greater than B2, the ECU 11 determines that a pumping braking operation has been performed that places such a burden on the driver that the driver has no time to view the display device 15. In other words, to determine that a pumping braking operation that places such a burden on the driver has been performed, not only must there be a moment when the brake stroke amount is equal to or less than Bp, but the brake stroke amount must also be greater than B2.

[0037] Next, referring to the flowchart shown in FIG. 2, the operation flow of the ECU 11 according to this embodiment will be described. In FIG. 2, the charge state display control and the reason display control are collectively referred to as normal control. Also, in FIG. 2, the brake stroke amount is represented by B, and the average value of the brake stroke amount is represented by Ba. Further, a threshold value for determining whether a normal brake operation of gently depressing the brake pedal 13 once has been performed is represented by B1, and threshold values for determining whether a pumping brake operation of depressing the brake pedal 13 relatively strongly in multiple steps has been performed are represented by B2 and Bp. In these threshold values, Bp < B1 < B2 holds.

[0038] As shown in FIG. 2, the ECU 11 determines whether the vehicle speed is 0 (step S1). In other words, the ECU 11 determines whether the vehicle is stopped. If the vehicle speed is not 0 (NO in step S1), since the vehicle is running, the ECU 11 proceeds to step S5 and performs normal control. The normal control in this case is the charge state display control, and the charge state of the lithium-ion battery 16 is displayed on the display device 15.

[0039] When the vehicle speed is 0 (YES in step S1), the ECU 11 determines whether an idling stop (denoted as IS in the figure) is in progress (step S2). In this step S2, the ECU 11 determines whether the engine 2 has been automatically stopped due to the fulfillment of the automatic stop condition. If the idling stop is in progress (YES in step S2), the ECU 11 proceeds to step S5 and performs normal control. In the normal control in this case, the idling stop time, which is the duration of the automatic stop of the engine 2, is displayed on the display device 15 in a manner such as "Idling stop time 1:23".

[0040] If the idling stop is not being performed (NO in step S2), the ECU 11 determines whether there was a period during the immediately preceding deceleration where B≦Bp (step S3). In this way, when the vehicle is stopped but the idling stop is not being performed, the ECU 11 compares the brake stroke amount during the deceleration period while the vehicle was traveling immediately before the vehicle stopped with the threshold value, and determines the display content of the display device 15 based on the comparison result.

[0041] If there was no period during the immediately preceding deceleration where B≦Bp (NO in step S3), the ECU 11 determines whether Ba≦B1 holds during deceleration (step S4). In this way, if a pumping brake operation was not performed and there was no period during the immediately preceding deceleration where B≦Bp, the ECU 11 uses B1 as the threshold value.

[0042] If the ECU 11 determines that Ba≦B1 during deceleration is not satisfied (NO in step S4), the ECU 11 proceeds to step S5.

[0043] If the ECU 11 determines that Ba≦B1 during deceleration is true (YES in step S4), the ECU 11 proceeds to step S6.

[0044] If there was a period during the immediately preceding deceleration where B≦Bp (YES in step S3), the ECU 11 determines whether Ba≦B2 during deceleration is satisfied (step S6). In this way, if a pumping brake operation was performed and there was a period during the immediately preceding deceleration where B≦Bp, the ECU 11 uses B2 as the threshold value. If Ba≦B2 during deceleration is not satisfied (NO in step S6), the ECU 11 proceeds to step S5.

[0045] The ECU 11 performs normal control in step S5 and ends this operation.

[0046] The ECU 11 performs non-display control in step S6 and ends this operation.

[0047] Next, referring to the timing chart shown in FIG. 3, the transition of the vehicle state during the operation of the ECU 11 according to this embodiment will be described. In FIG. 3, the vertical axis represents the display content of the display device 15, the brake stroke amount, and the vehicle speed, and the horizontal axis represents time. In FIG. 3, a threshold value B1 is represented for determining whether a normal braking operation of gently depressing the brake pedal 13 once has been performed, and threshold values B2 and Bp are represented for determining whether a pumping brake operation of relatively strongly depressing the brake pedal 13 in multiple steps has been performed. Among these threshold values, Bp < B1 < B2 holds. In the item of the display content in FIG. 3, (1) represents the charge state display control, (2)-1 represents the reason display control, and (2)-2 represents the non-display control. In FIG. 3, the automatic stop condition does not hold in any period.

[0048] As shown in FIG. 3, at the initial time t0, the brake stroke amount is 0 and the vehicle speed is constant. At this time t0, the vehicle 1 is in a state of traveling at a constant speed. Therefore, the display content becomes (1).

[0049] Thereafter, the brake stroke amount increases to B2 and the vehicle speed decreases. Also, at time t1, the brake stroke amount is maintained at B2 and the decrease in the vehicle speed continues.

[0050] Thereafter, at time t2, the vehicle speed decreases to 0 and the vehicle stops. Then, it is determined whether there is a moment when the brake stroke amount becomes equal to or less than Bp, which is the determination threshold value for the pumping brake operation, within a certain period Tp before the vehicle stops. Since the brake stroke amount has not become equal to or less than Bp, the threshold value is set to B1. Also, it is determined whether the brake stroke amount has always been equal to or less than B1 within a certain period T1 before the vehicle stops, and it is determined that it has not always been equal to or less than B1. Therefore, it is presumed that the driver did not have a margin to visually recognize the display device 15 because the vehicle stopped with a large brake operation amount exceeding B1. For this reason, at this time t2, the display content is switched to (2)-1 and the reason display control is implemented.

[0051] After that, at time t3, the brake stroke amount decreases to 0, and the vehicle speed increases. At this time t3, the display content is switched to (1).

[0052] Thereafter, the brake stroke amount increases to a value greater than Bp but equal to or less than B1, and the vehicle speed decreases.

[0053] Thereafter, at time t5, the vehicle speed decreases to 0, and the vehicle comes to a stop. Then, it is determined whether there was a moment when the brake stroke amount was equal to or less than Bp, which is the threshold for determining pumping brake operation, within a certain period Tp before the vehicle stopped. Then, since the brake stroke amount was not equal to or less than Bp, the threshold is set to B1. It is also determined whether the brake stroke amount was always equal to or less than B1 within a certain period T1 before the vehicle stopped, and it is determined that it was always equal to or less than B1. Therefore, since the vehicle came to a stop with a small brake operation amount equal to or less than B1, it is presumed that the driver had enough time to view the display device 15. Therefore, at this time t5, the display content is switched to (2)-2, and non-display control is performed.

[0054] After that, at time t6, the brake stroke amount decreases to 0, and the vehicle speed increases. At this time t6, the display content is switched to (1).

[0055] After that, the brake stroke amount temporarily increases to B2 and then becomes 0, and the vehicle speed decreases.

[0056] After that, at time t7, the brake stroke amount increases to a value between B1 and B2.

[0057] Thereafter, at time t8, the vehicle speed decreases to 0, and the vehicle comes to a stop. Then, it is determined whether or not there was a moment when the brake stroke amount was equal to or less than Bp, which is the determination threshold for pumping brake operation, within a certain period Tp before the vehicle stopped. Then, since the brake stroke amount is equal to or less than Bp, the threshold is set to B2. It is also determined whether or not the brake stroke amount was always equal to or less than B2 within a certain period T2 before the vehicle stopped, and it is determined that it was always equal to or less than B2. Therefore, it is presumed that a pumping brake operation that places such a heavy burden on the driver that the driver could not afford to view the display device 15 was not performed, and the driver had enough time to view the display device 15. Therefore, at this time t8, the display content is switched to (2)-2, and non-display control is performed.

[0058] As described above, in this embodiment, while the vehicle is traveling, the ECU 11 performs charge state display control to display the charge state of the lithium-ion battery 16 on the display device 15. Furthermore, when the vehicle is stopped and the automatic stop of the engine 2 is not implemented because the charge state of the lithium-ion battery 16 or the lead battery 17 is less than a predetermined charge state, the ECU 11 performs reason display control to display that the charge state is less than the predetermined charge state as the reason for not automatically stopping the engine 2, without specifying whether the lithium-ion battery 16 or the lead battery 17 is being charged. Furthermore, when the vehicle is stopped and the automatic stop of the engine 2 is not implemented because the charge state of the lithium-ion battery 16 is equal to or greater than the predetermined charge state but the charge state of the lead battery 17 is less than the predetermined charge state, and the ECU 11 determines, based on the brake stroke amount during the deceleration period while the vehicle is traveling immediately before the vehicle is stopped, that the driver had enough time to visually confirm the charge state of the lithium-ion battery 16 on the display device 15 during the deceleration period. Therefore, the ECU 11 performs non-display control to not display on the display device 15 the reason for not automatically stopping the engine 2.

[0059] As a result, in a situation where the charge state of lithium-ion battery 16 is sufficient to perform an idling stop but a low charge state of lead battery 17 makes it impossible to perform an idling stop, if it is determined that the driver had enough time to visually check the charge state of lithium-ion battery 16 on display device 15 during deceleration, non-display control is implemented to not display the reason, rather than displaying the reason that the charge state is below a predetermined charge state without specifying whether it is lithium-ion battery 16 or lead battery 17. This eliminates the inconsistency that occurs when "charging" is displayed as the reason for not automatically stopping engine 2 when the vehicle is stopped, even though the charge state of lithium-ion battery 16 was displayed as fully charged while the vehicle was traveling. As a result, it is possible to prevent the driver from feeling uncomfortable due to an inconsistency between the display of the battery charge state and the display related to the automatic stopping of engine 2.

[0060] In addition, in this embodiment, if the average value of the brake stroke amount during the deceleration period is less than a predetermined value, the ECU 11 determines that the driver had enough time to visually check the charge state of the lithium ion battery 16 on the display device 15 during the deceleration period.

[0061] As a result, if the average value of the brake stroke amount during the deceleration period is equal to or less than a predetermined value, it can be accurately determined that the driver had enough time to visually check the charge state of the lithium-ion battery 16 because the driver's brake operation is not burdened with much.

[0062] In this embodiment, if the average value of the brake stroke amount during the deceleration period is greater than a predetermined value, the ECU 11 determines that the driver did not have time to visually check the state of charge of the lithium ion battery 16 on the display device 15.

[0063] As a result, if the average value of the brake stroke amount during the deceleration period is greater than a predetermined value, it can be accurately determined that the driver was not able to visually check the charge state of the lithium ion battery 16 due to the situation in which the driver was under a heavy burden in braking operation.

[0064] In addition, in this embodiment, the ECU 11 compares the brake stroke amount during the deceleration period with a judgment threshold value that determines whether or not the brake is being pumped, and if the brake stroke amount is continuously greater than the judgment threshold value, the ECU 11 uses the first predetermined value as the predetermined value, and if there is a moment when the brake stroke amount is equal to or less than the judgment threshold value, the ECU 11 uses a second predetermined value greater than the first predetermined value as the predetermined value.

[0065] As a result, during pumping brake operation, the amount of brake stroke per operation tends to be larger due to the amount of brake release, and if the judgment were made using the first predetermined value, it may be erroneously determined that there is not enough time to see the display device 15. However, by making the judgment using the second predetermined value, which has a stroke amount larger than the first predetermined value, it is possible to more accurately determine whether the driver has enough time to see the charge state of the lithium-ion battery 16.

[0066] While an embodiment of the present invention has been disclosed, it will be apparent to one skilled in the art that modifications may be made thereto without departing from the scope of the present invention, and it is intended that all such modifications and equivalents be included in the following claims. [Explanation of symbols]

[0067] 1 vehicle 2 engines 6 Auxiliary equipment 11 ECU (idling stop control unit, display control unit) 13A brake stroke sensor 14 Vehicle speed sensor 15 Display device 16 Lithium-ion battery (first battery) 17 Lead acid battery (second battery)

Claims

1. The engine and a first battery that supplies power to an auxiliary device during automatic stop of the engine; a second battery that supplies power to the auxiliary equipment while the engine is running; a brake stroke sensor that detects the amount of brake stroke of the driver's brake operation; a vehicle speed sensor for detecting a vehicle speed; a display device that displays the vehicle status; an idling stop control unit that automatically stops the engine when a predetermined automatic stop condition is met, the automatic stop condition including that the charge states of both the first battery and the second battery are equal to or higher than a predetermined charge state, and that restarts the engine when a predetermined restart condition is met, a display control unit that controls the display content of the display device; The display control unit While the vehicle is running, a charge state display control is performed to display the charge state of the first battery on the display device; when the vehicle is stopped and the automatic stop of the engine is not implemented because the state of charge of the first battery or the second battery is less than the predetermined state of charge, a reason display control is performed to display the fact that the state of charge is less than the predetermined state of charge as the reason for the automatic stop of the engine, without identifying the first battery or the second battery; A vehicle control device characterized in that, when the vehicle is stopped and the automatic stop of the engine is not implemented because the charge state of the first battery is equal to or greater than the predetermined charge state but the charge state of the second battery is less than the predetermined charge state, and when it is determined based on the brake stroke amount during the deceleration period while the vehicle is traveling immediately before the vehicle is stopped that the driver had enough time to visually confirm the charge state of the first battery on the display device during the deceleration period, the vehicle control device performs non-display control to not display on the display device the reason why the automatic stop of the engine is not implemented.

2. 2. The vehicle control device according to claim 1, wherein the display control unit determines that the driver had enough time to visually check the charge state of the first battery on the display device during the deceleration period if the average value of the brake stroke amount during the deceleration period is equal to or less than a predetermined value.

3. 3. The vehicle control device according to claim 2, wherein the display control unit determines that the driver did not have enough time to visually check the charge state of the first battery on the display device when the average value of the brake stroke amount during the deceleration period is greater than the predetermined value.

4. The display control unit compares the brake stroke amount during the deceleration period with a determination threshold value to determine whether or not the brake is being pumped, 4. A vehicle control device as described in claim 2 or claim 3, characterized in that if the brake stroke amount is continuously greater than the judgment threshold, a first predetermined value is used as the predetermined value, and if there is a moment when the brake stroke amount is less than or equal to the judgment threshold, a second predetermined value greater than the first predetermined value is used as the predetermined value.

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