Vehicle power supply device

Abstract

The present invention relates to and provides a vehicle power supply device that can stabilize the operation of a vehicle-mounted load with minimal power when the vehicle is shifted from an idle stop state to an engine restart. The vehicle power supply device (11) comprises: a DCDC converter (14) for converting the voltage of power output from a normal power supply (12), a power storage unit connected to the DCDC converter (14), and a DCDC control unit (161). When the idle stop function ends, the DCDC control unit (161) supplies the power converted by the DCDC converter (14) to either a first vehicle load or a second vehicle load, and supplies the power from the normal power supply (12) to either the first vehicle load or the second vehicle load.

Description

Technical Field

[0001] The present invention relates to a vehicle power supply device, and more particularly to a vehicle power supply device installed in a vehicle having an idling stop function. Background Art

[0002] In the vehicle possessing engine, in recent years, the vehicle possessing idling stop function has appeared. In existing vehicles, even when stopping, the idling speed of the engine is also carried out, but in the idling stop function, in order to save fuel or reduce exhaust gas etc., unnecessary idling is stopped when parking.

[0003] When the vehicle is started from an idling stop, the engine is restarted. Patent Document 1 describes an invention in which power is supplied from a capacitor or the like in addition to a main power source such as a battery when the engine is restarted.

[0004] Furthermore, Patent Document 2 describes an invention in which loads mounted on a vehicle are divided into several groups, priorities are assigned to the groups, and power is selectively supplied.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2015-217919

[0008] Patent Document 2: Japanese Patent Application Laid-Open No. 2003-165406 Summary of the Invention

[0009] Problems to be solved by the invention

[0010] However, while the invention described in Patent Document 1 discloses the technical consideration of supplying power to a load from an auxiliary power source, such as a capacitor, when the engine is restarted after recovering from an idle stop, it does not adequately address the amount of power supplied from the auxiliary power source. If the amount of power supplied to the load from the auxiliary power source is insufficient, settings such as vehicle navigation settings may be inadvertently reset.

[0011] Furthermore, during engine restart, the voltage drop in the vehicle's main power source (lead-acid battery) reduces the DC-DC converter's boost efficiency. This increases the current flowing between the battery and the DC-DC converter input, causing a voltage drop due to the wiring resistance between the two. While increasing the diameter of the wiring harness to reduce wiring resistance is a possible solution, this approach presents difficulties in wiring harness layout. Another approach to addressing this voltage drop is increasing the converter's capacity, but this can lead to increased device size and cost.

[0012] Furthermore, the invention described in Patent Document 2 divides the loads mounted on a vehicle into several groups and assigns priority to each group. However, in this invention, only the power supply to some groups is cut off in the event of an accident. Therefore, this invention cannot guarantee the operation of the loads when the engine is restarted after recovering from an idling stop.

[0013] The present invention has been made in view of such problems, and an object of the present invention is to provide a vehicle power supply device that can stabilize the operation of a vehicle-mounted load with minimal electric power when shifting from an idling stop state to an engine restart.

[0014] Technical solutions to solve problems

[0015] A vehicle power supply device according to a first aspect of the present invention converts electric power supplied from a normal power supply to a vehicle load in a vehicle having an idle stop function, wherein the device comprises a power conversion circuit for converting the voltage of the electric power output from the normal power supply, a power storage unit connected to the power conversion circuit, and an operation and control device, wherein the vehicle load includes a first vehicle load related to the travel of the vehicle and a second vehicle load unrelated to the travel of the vehicle, and wherein the operation and control device supplies the electric power converted by the power conversion circuit to either the first vehicle load or the second vehicle load, and supplies the electric power from the normal power supply to either the other of the first vehicle load and the second vehicle load when the idle stop function ends.

[0016] In addition, in the vehicle power supply device described in the second aspect of the present invention, the operation control device supplies the power converted by the power conversion circuit to the second vehicle load when the idle stop function ends when the vehicle is stopped, and then supplies the power from the storage unit to the second vehicle load when the engine is restarted, and supplies the power converted by the power conversion circuit to the first vehicle load when the idle stop function ends when the vehicle is running, and then supplies the power from the storage unit to the first vehicle load when the engine is restarted.

[0017] In addition, in the vehicle power supply device described in the third aspect of the present invention, the first vehicle load includes a steering system load and a braking system load, and the operation control device supplies the power converted by the power conversion circuit to the braking system load when the idle stop function ends while the vehicle is traveling, and then supplies the power from the storage unit to the braking system load when the engine is restarted.

[0018] In the vehicle power supply device according to claim 4 of the present invention, a third vehicle load related to an emergency operation of the vehicle is further provided, and the calculation control device supplies power from the power storage unit only to the third vehicle load during the emergency operation.

[0019] Furthermore, in the vehicle power supply apparatus according to claim 5 of the present invention, the second vehicle load is a display device.

[0020] Effects of the Invention

[0021] According to the first aspect of the present invention, the vehicle power supply device classifies vehicle loads into a first vehicle load related to vehicle travel and a second vehicle load unrelated to vehicle travel. When the idle stop function terminates, power from either the normal power supply or the power conversion circuit is supplied to the first vehicle load, while power from the other is supplied to the second vehicle load. Thus, power supplied from the power conversion circuit at a stabilized voltage can be supplied to either the first or second vehicle load. Thus, when power from the power conversion circuit is supplied to the first vehicle load, functions related to vehicle travel can be operated stably. Furthermore, when power from the power conversion circuit is supplied to the second vehicle load, functions unrelated to vehicle travel, such as a display device, can be operated stably.

[0022] According to the vehicle power supply device of the second aspect of the present invention, first, when the vehicle is stopped, at the end of the idle stop function, the power converted by the power conversion circuit is supplied to the second vehicle load, and then, when the engine is restarted, the power from the power storage unit is supplied to the second vehicle load. In this way, when the idle stop function ends, stable power can be supplied to the second vehicle load, such as the display device, so that the second vehicle load can operate stably. On the other hand, when the vehicle is running, at the end of the idle stop function, the power converted by the power conversion circuit is supplied to the first vehicle load, and then, when the engine is restarted, the power from the power storage unit is supplied to the first vehicle load. In this way, during driving, the first vehicle load, such as the braking device, can be operated stably and with a minimum of power from the main power supply.

[0023] According to the vehicle power supply device of the third aspect of the present invention, when the vehicle is running, at the end of the idle stop function, the power converted by the power conversion circuit is supplied to the brake system load, and thereafter, when the engine is restarted, the power from the storage unit is supplied to the brake system load. As a result, when the vehicle is running, for example, the brake system load can be operated stably and with a minimum of power from the main power supply.

[0024] According to the vehicle power supply device of the fourth aspect of the present invention, during emergency operation, power is supplied only to the third vehicle load from the power storage unit. Therefore, even if the normal power supply is damaged due to a collision accident, for example, the door lock release mechanism, i.e., the third vehicle load, can be activated, allowing the occupants to escape from the vehicle.

[0025] According to the vehicle power supply apparatus of the fifth aspect of the present invention, by using the display device as the second vehicle load, it is possible to suppress the display device from flickering when the idling stop function ends. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figures 1(A)-(B) are diagrams showing a vehicle power supply device according to an embodiment of the present invention. Figure 1(A) is a block diagram showing a connection structure of a vehicle incorporating the vehicle power supply device, and Figure 1(B) is a circuit diagram showing the vehicle power supply device.

[0027] Figure 2 1 is a diagram showing a vehicle power supply device according to an embodiment of the present invention, and is a timing chart showing changes in power supply voltage in various periods during engine restart.

[0028] Figures 3(A)-(B) are diagrams showing a vehicle power supply device according to an embodiment of the present invention. Figure 3(A) is a time diagram showing the change in power supply voltage during period A when the engine is restarted, and Figure 3(B) is a circuit diagram showing the operation of the vehicle power supply device during period A.

[0029] Figures 4(A)-(B) are diagrams of a vehicle power supply device when the vehicle is stopped according to an embodiment of the present invention, Figure 4(A) is a time diagram showing the changes in the power supply voltage during periods B and D when the engine is restarted, and Figure 4(B) is a circuit diagram showing the operation of the vehicle power supply device during periods B and D.

[0030] Figure 5(A)-(B) is a diagram of a vehicle power supply device when the vehicle is stopped according to an embodiment of the present invention, Figure 5(A) is a time diagram showing the change in power supply voltage during period C when the engine is restarted, and Figure 5(B) is a circuit diagram showing the operation of the vehicle power supply device during period C.

[0031] Figures 6(A)-(B) are diagrams of a vehicle power supply device when a vehicle is traveling according to an embodiment of the present invention. Figure 6(A) is a time diagram showing the changes in the power supply voltage during periods B and D when the engine is restarted. Figure 6(B) is a circuit diagram showing the operation of the vehicle power supply device during periods B and D.

[0032] Figures 7(A)-(B) are diagrams of a vehicle power supply device when a vehicle is traveling according to an embodiment of the present invention. Figure 7(A) is a time diagram showing the change in power supply voltage during period C when the engine is restarted, and Figure 7(B) is a circuit diagram showing the operation of the vehicle power supply device during period C.

[0033] Figure 8 This is a circuit diagram showing an emergency vehicle power supply device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0034] Hereinafter, a vehicle power supply device 11 according to an embodiment of the present invention will be described in detail with reference to the drawings. In the following description, the same components are denoted by the same reference numerals in principle, and redundant descriptions are omitted.

[0035] Here, an example of the correspondence between the claims and the embodiments is described. The power conversion circuit is a DC-DC converter 14 , the power storage unit is a capacitor 15 , the arithmetic control device is a DC-DC control unit 161 , the first vehicle load is a steering system load 131 and a braking system load 132 , the second vehicle load is a display system load 134 , and the third vehicle load is an emergency system load 133 .

[0036] 1(A) and (B) illustrate the structure of vehicle power supply device 11. FIG1(A) is a block diagram schematically showing the structure of vehicle 10 including vehicle power supply device 11, and FIG1(B) is a circuit diagram showing the structure of vehicle power supply device 11 in detail.

[0037] Referring to Figure 1(A), a vehicle 10 includes a normal power supply 12, a vehicle power supply device 11, and a vehicle load 13. Vehicle 10 is driven by an engine (not shown) and includes an idling stop function. The idling stop function prevents unnecessary idling when the vehicle 10 is stopped at an intersection, for example, to save fuel or reduce exhaust emissions.

[0038] The normal power source 12 supplies power to the vehicle load 13. The normal power source 12 is, for example, a rechargeable lead battery or lithium-ion battery that generates 12V DC power.

[0039] The vehicle load 13 is a load mounted on the vehicle 10. The details of the vehicle load 13 will be described later with reference to FIG1(B).

[0040] The vehicle power supply device 11 converts electric power supplied from the normal power supply 12 to the vehicle load 13. The details of the vehicle power supply device 11 will be described later with reference to FIG1(B).

[0041] The circuit configuration of a vehicle power supply device 11 will be described with reference to FIG1B . In a vehicle 10 equipped with an idling stop function, the vehicle power supply device 11 converts the power supplied from a normal power supply 12 to a vehicle load 13. The vehicle power supply device 11 primarily includes a DC-DC converter 14 that converts the voltage of the power output from the normal power supply 12, a capacitor 15 connected to the DC-DC converter 14, and a DC-DC control unit 161.

[0042] The vehicle loads 13 described above include a first vehicle load (a steering system load 131 and a braking system load 132, described later) that are related to the travel of the vehicle 10, and a second vehicle load (a display system load 134, described later) that is not directly related to the travel of the vehicle 10. Furthermore, as described later, when the idle stop function is terminated, the DCDC control unit 161 supplies the power converted by the DCDC converter 14 to either the first or second vehicle load, and supplies the power from the normal power supply 12 to the other of the first and second vehicle loads.

[0043] Specifically, the vehicle power supply device 11 mainly includes a capacitor 15, a DC-DC converter 14, a circuit switch 291, a circuit switch 292, a circuit switch 293, and a circuit switch 294. Furthermore, the vehicle loads 13 shown in the figure include a steering system load 131, a braking system load 132, an emergency system load 133, and a display system load 134.

[0044] The specific structure of the vehicle power supply device 11 will be described in detail together with the normal power supply 12 and the vehicle load 13 .

[0045] Typically, one electrode of the power source 12 is grounded, and the other electrode is connected to the steering system load 131 via a connection line 318 .

[0046] One electrode of the alternator 23 is grounded, and the other electrode is connected to the circuit switching unit 292 via a connection line 311. A diode 181 and a resistor 19 are connected to the connection line 311 from the alternator 23 side. The alternator 23 is driven by an engine (not shown).

[0047] The starter 22 is a starting motor for converting the power supplied from the normal power supply 12 into rotational energy and rotating the engine to a level at which it can operate independently. One electrode of the starter 22 is grounded, and the other electrode is connected to the contact 233 of the connecting line 311 via the connecting line 312.

[0048] One electrode of the capacitor 15 is grounded, and the other electrode is connected to a contact point 234 of the connection line 311 via a connection line 313. The contact point 234 is arranged between the diode 181 and the resistor 19.

[0049] The DCDC control unit 161 is a component that controls the overall operation of the vehicle power supply device 11 , and an ECU (Electronic Control Unit) can be employed, for example.

[0050] The airbag control unit 162 is an ECU that controls the inflation of the airbag. In this embodiment, the airbag control unit 162 transmits an electrical signal to the DCDC control unit 161 indicating that the airbag has inflated, that is, that a vehicle collision has occurred.

[0051] The engine control unit 163 is an ECU that controls the operation of the engine. The engine control unit 163 transmits an electrical signal indicating that the engine should be restarted when the idling stop is completed to the DCDC control unit 161.

[0052] Here, the DCDC converter 14 is a step-up type DCDC converter and is a circuit element that steps up and stabilizes the power supplied from the normal power supply 12 . The input electrode of the DCDC converter 14 is connected to the connection line 315 , and the output electrode is connected to the connection line 319 .

[0053] Steering load 131 is a load that causes vehicle 10 to steer. This load is controlled by the driver's steering wheel operation. Steering load 131 is also known as a power steering device. One electrode of steering load 131 is grounded, and the other electrode is connected to the normal power supply 12 via a connection line 318.

[0054] Braking system load 132 is a load that brakes vehicle 10. This load is applied based on the amount the occupant depresses the brake pedal. One electrode of braking system load 132 is grounded, and the other electrode is connected to connecting line 318 via connecting line 326 and contact 238. Braking system load 132 can include a brake assist system, ABS (Antilock Brake System), or VDC (Vehicle Dynamics Control).

[0055] Emergency system load 133 is a load associated with emergency operations of vehicle 10, such as the door lock mechanism or the emergency notification function. One electrode of emergency system load 133 is grounded, and the other electrode is connected to normal power supply 12 via connection line 325, contact 237, and connection line 318. Furthermore, the other electrode of emergency system load 133 is connected to circuit switching unit 294 via connection line 324.

[0056] Compared to steering system load 131 and braking system load 132, display system load 134 is a device not directly related to the driving function of vehicle 10, such as a display, car navigation system, audio system, and meter. One electrode of display system load 134 is grounded, and the other electrode is connected to circuit switching unit 294 via connection line 323. Furthermore, the other electrode of display system load 134 is connected to contact point 236 via connection line 322.

[0057] Connection line 316 connects connection point 231 of connection line 318 to circuit switching unit 292. Connection line 317 connects connection point 232 of connection line 318 to circuit switching unit 291. Connection line 321 connects connection point 239 of connection line 326 to circuit switching unit 293. Connection line 311 and connection line 318 are connected at connection point 240.

[0058] The circuit switching unit 291 is a switching element interposed between the connection line 317 and the connection line 319 , and can be a semiconductor element such as a transistor. The circuit switching unit 291 connects the connection line 317 and the connection line 319 based on an instruction from the DCDC control unit 161 .

[0059] Circuit switching unit 292 is a switching element disposed between connection line 315, connection line 311, and connection line 316. For example, a semiconductor element such as a transistor can be employed. Based on instructions from DCDC control unit 161, circuit switching unit 292 connects connection line 311 to connection line 315 or connects connection line 316 to connection line 315.

[0060] Circuit switching unit 293 is a switching element disposed between contact 235, connection line 321, and connection line 320. For example, a semiconductor element such as a transistor can be employed. Based on instructions from DCDC control unit 161, circuit switching unit 293 connects contact 235 to connection line 321 or connects contact 235 to connection line 320.

[0061] Circuit switching unit 294 is a switching element disposed between connection line 320, connection line 324, and connection line 323. For example, a semiconductor element such as a transistor can be employed. Based on instructions from DCDC control unit 161, circuit switching unit 294 connects connection line 320 to connection line 324 or connects connection line 320 to connection line 323.

[0062] The diode 182 is inserted in the middle of the connection line 322 , the diode 183 is inserted in the middle of the connection line 325 , and the diode 184 is inserted in the middle of the connection line 326 .

[0063] Reference Figure 2In a vehicle with an idling stop function, the period from when the idling stops to when the engine is restarted can be divided into a period A to a period D. Figure 2 It is a graph showing the voltage value of the normal power supply 12.

[0064] The period A is a period during which the DCDC converter 14 does not operate, and the voltage of the power source 12 is normally stable at, for example, approximately 12V.

[0065] The period B is the period from when the engine is in the idle stop state to immediately before it is restarted.

[0066] The period C is a period including the moment when the engine is restarted and immediately thereafter.

[0067] Period D is a period from the end of period C until the voltage is restored.

[0068] Here, the behavior of the vehicle power supply device 11 during periods B, C, and D is different when the vehicle 10 is stopped and the engine is restarted from idling stop, and when the vehicle 10 is running and the engine is restarted from idling stop. Figures 4(A)-(B) and 5(A)-(B) show the situation when the vehicle 10 is stopped and the engine is restarted. Figures 6(A)-(B) and 7(A)-(B) show the situation when the vehicle 10 is running and the engine is restarted from idling stop. In addition, the behavior of the vehicle power supply device 11 during period A is the same when the vehicle 10 is stopped and the engine is restarted from idling stop, and when the vehicle 10 is running and the engine is restarted.

[0069] The operation of vehicle power supply device 11 during period A when vehicle 10 is stopped will be described with reference to Figures 3(A) and 3(B). The flow of current is indicated by a dotted line. Figure 3(A) is a graph illustrating period A, and Figure 3(B) is a circuit diagram illustrating the operation of vehicle power supply device 11 during period A.

[0070] 3(A), during period A, the voltage of the power supply 12 is normally stable at, for example, approximately 12V.

[0071] 3B , during period A, circuit switching section 291 is conductive and circuit switching section 292 is non-conductive. Circuit switching section 293 connects contact 235 to connection line 320 , and circuit switching section 294 connects connection line 320 to connection line 323 .

[0072] Thus, the power from the normal power supply 12 is supplied to the steering load 131 via the connection line 318. The power from the normal power supply 12 is stored in the capacitor 15 via the connection line 318, the contact 240, the connection line 311, the contact 234, and the connection line 313.

[0073] Furthermore, the electric power from the normal power supply 12 is supplied to the brake system load 132 via the connection line 318 , the contact point 238 , and the connection line 326 .

[0074] Furthermore, the electric power from the normal power source 12 is supplied to the emergency system load 133 via the connection line 318 , the contact point 237 , and the connection line 325 .

[0075] Furthermore, power from the normal power supply 12 is supplied to the display system load 134 via the connection line 318 , the contact 232 , the connection line 317 , the circuit switching unit 291 , the connection line 319 , the contact 235 , the circuit switching unit 293 , the connection line 320 , the circuit switching unit 294 , and the connection line 323 .

[0076] As described above, by operating the vehicle power supply device 11 , stable power is supplied from the normal power supply 12 to the steering system load 131 , the brake system load 132 , the emergency system load 133 , and the display system load 134 , enabling these loads to operate stably.

[0077] The operation of the vehicle power supply device 11 when the vehicle 10 is stopped from idling to restarting the engine will be described with reference to FIG. 4(A)-(B) and FIG. 5(A)-(B).

[0078] Referring to Figures 4(A) and 4(B), the operation of vehicle power supply device 11 during period B, which is the period from the idle stop state to just before the engine is restarted, and during period D, when vehicle 10 is traveling with the engine's driving force after the idle stop function ends, will be described. Figure 4(A) is a graph showing period B and period D, and Figure 4(B) is a circuit diagram showing the operation of vehicle power supply device 11 during periods B and D.

[0079] Referring to Figure 4(A), during period B, the voltage of power supply 12 is generally relatively stable, for example, at approximately 12V. Period B, for example, occurs when the engine is stopped by the idle stop function, from the time the occupant releases their foot from the brake pedal until the engine restarts. During period B, the voltage of power supply 12 generally does not drop. Period D is the period from the end of period C until the voltage recovers.

[0080] 4B , during periods B and D, circuit switching section 291 is in a non-conductive state, and circuit switching section 292 connects connection line 315 to connection line 316. Furthermore, circuit switching section 293 connects contact 235 to connection line 320, and circuit switching section 294 connects connection line 320 to connection line 323.

[0081] In this manner, the power from the normal power supply 12 is supplied to the DCDC converter 14 via the connection line 318, the contact 231, the connection line 316, the circuit switching unit 292, and the connection line 315. Furthermore, the power stabilized at a predetermined voltage value by the DCDC converter 14 is supplied to the display system load 134 via the connection line 319, the contact 235, the circuit switching unit 293, the connection line 320, the circuit switching unit 294, and the connection line 323.

[0082] Furthermore, electric power from the normal power supply 12 is supplied to the steering system load 131 via the connection line 318 .

[0083] Furthermore, the power from the normal power supply 12 is supplied to the brake system load 132 via the connection line 318, the contact 238, and the connection line 326. The power from the normal power supply 12 is supplied to the emergency system load 133 via the connection line 318, the contact 237, and the connection line 325.

[0084] In this manner, the power having a stabilized voltage by the DCDC converter 14 can be supplied to the display system load 134 , which is, for example, a car navigation device, and flickering of the display system load 134 can be suppressed.

[0085] 5(A)-(B) , the operation of vehicle power supply device 11 during period C, which includes the moment the engine restarts when vehicle 10 is stopped and shortly thereafter, will be described. FIG5(A) is a graph illustrating period C, and FIG5(B) is a circuit diagram illustrating the operation of vehicle power supply device 11 during period C.

[0086] 5(A) , during period C, a voltage drop occurs due to a voltage drop caused by wiring resistance or power consumption by starter 22 for restarting the engine.

[0087] 5B , during period C, circuit switching section 291 is in a non-conductive state, and circuit switching section 292 connects connection line 315 to connection line 311 . Furthermore, circuit switching section 293 connects contact 235 to connection line 320 , and circuit switching section 294 connects connection line 320 to connection line 323 .

[0088] In this manner, the power from capacitor 15 is supplied to DCDC converter 14 via connection line 313, contact 234, resistor 19, connection line 311, circuit switching unit 292, and connection line 315. Furthermore, the power stabilized at a predetermined voltage value by DCDC converter 14 is supplied to display system load 134 via connection line 319, contact 235, circuit switching unit 293, connection line 320, circuit switching unit 294, and connection line 323.

[0089] Furthermore, power from the normal power supply 12 is supplied to the steering system load 131 via the connection line 318. Furthermore, power from the normal power supply 12 is supplied to the brake system load 132 via the connection line 318, the contact 238, and the connection line 326. Furthermore, power from the normal power supply 12 is supplied to the emergency system load 133 via the connection line 318, the contact 237, and the connection line 325.

[0090] Thus, the power supplied from capacitor 15 and stabilized in voltage by DCDC converter 14 can be supplied to display system load 134 , such as a car navigation device, and discontinuous operation of display system load 134 , such as flickering, can be suppressed.

[0091] The operation of the vehicle power supply device 11 when the vehicle 10 is running from idling stop to restarting the engine will be described with reference to FIG. 6(A)-(B) and FIG. 7(A)-(B).

[0092] The following describes the process of resetting the engine from idle stop while vehicle 10 is traveling. In recent years, to maximize the fuel efficiency benefits of idle stop, a pre-stop idle stop, in which the engine stops when the vehicle speed drops below a certain level, has become common. In this case, before the vehicle stops after the speed drops below a certain level, the occupant often steps on the accelerator again, accelerating the vehicle. This phenomenon is also known as resetting the engine. During this resetting process, the vehicle power supply unit 11 operates as follows to stabilize the loads associated with the travel of vehicle 10.

[0093] Referring to Figures 6(A) and 6(B), the operation of vehicle power supply device 11 during period B, which is the period from the idle stop state to just before the engine is restarted, and during period D, when vehicle 10 is traveling with the engine's driving force after the idle stop function ends, will be described. Figure 6(A) is a graph showing period B and period D, and Figure 6(B) is a circuit diagram showing the operation of vehicle power supply device 11 during periods B and D.

[0094] 6(A) , during period B, the voltage of the normal power supply 12 is relatively stable at, for example, approximately 12 V. Furthermore, during period D, the voltage of the normal power supply 12 is restored to, for example, approximately 12 V.

[0095] 6B , during periods B and D, circuit switch 291 is in a non-conductive state, and circuit switch 292 connects connection line 315 and connection line 316. Furthermore, circuit switch 293 connects contact 235 and connection line 321, and circuit switch 294 is in a non-connected state.

[0096] Thus, the electric power from the normal power supply 12 is supplied to the DC-DC converter 14 via the connection line 318, the contact 231, the connection line 316, the circuit switching unit 292, and the connection line 315. Furthermore, the electric power stabilized at a predetermined voltage value by the DC-DC converter 14 is supplied to the brake system load 132 via the connection line 319, the contact 235, the circuit switching unit 293, the connection line 321, the contact 239, and the connection line 326.

[0097] Furthermore, electric power from the normal power supply 12 is supplied to the steering system load 131 via the connection line 318 .

[0098] Furthermore, the electric power from the normal power source 12 is supplied to the emergency system load 133 via the connection line 318 , the contact point 237 , and the connection line 325 .

[0099] Furthermore, the power from the normal power supply 12 is supplied to the display system load 134 via the connection line 318 , the contact point 236 , and the connection line 322 .

[0100] In this manner, the electric power having a stabilized voltage by the DCDC converter 14 can be supplied to the brake system load 132 , and the brake system load 132 can be operated stably when the vehicle 10 is braked after a change of mind is made.

[0101] 7(A) and (B) illustrate the operation of vehicle power supply device 11 during period C, which includes the moment the engine is restarted and shortly thereafter, while the vehicle is traveling. FIG7(A) is a graph illustrating period C, and FIG7(B) is a circuit diagram illustrating the operation of vehicle power supply device 11 during period C.

[0102] 7(A) , during period C, a voltage drop may occur due to a voltage drop caused by wiring resistance or power consumption by the starter 22 such as a starter motor for restarting the engine.

[0103] 7B , during period C, circuit switching section 291 is in a non-conductive state, circuit switching section 292 connects connection line 315 to connection line 311. Circuit switching section 293 connects contact 235 to connection line 321. Circuit switching section 294 is in a non-connected state.

[0104] Thus, the power from capacitor 15 is supplied to DCDC converter 14 via connection line 313, resistor 19, connection line 311, circuit switching unit 292, and connection line 315. Furthermore, the power stabilized at a predetermined voltage value by DCDC converter 14 is supplied to brake system load 132 via connection line 319, contact 235, circuit switching unit 293, connection line 321, contact 239, and connection line 326.

[0105] Furthermore, power from the normal power supply 12 is supplied to the steering system load 131 via the connection line 318. Furthermore, power from the normal power supply 12 is supplied to the emergency system load 133 via the connection line 318, the contact 237, and the connection line 325. Furthermore, power from the normal power supply 12 is supplied to the display system load 134 via the connection line 318, the contact 236, and the connection line 322.

[0106] In this manner, the electric power supplied from the capacitor 15 and stabilized in voltage by the DCDC converter 14 can be supplied to the brake system load 132 , and the braking operation of the vehicle 10 at the time of the aforementioned change of mind can be reliably performed.

[0107] Figure 8 This circuit diagram illustrates the operation of vehicle power supply device 11 during an emergency, such as a collision involving vehicle 10. In the event of a collision involving vehicle 10, circuit switching unit 291 is disconnected, while circuit switching unit 292 connects connecting line 315 to connecting line 311. Furthermore, circuit switching unit 293 connects contact 235 to connecting line 320, and circuit switching unit 294 connects connecting line 320 to connecting line 324.

[0108] In this manner, even if the normal power supply 12 is damaged due to a collision of the vehicle 10 and the power supply from the normal power supply 12 is interrupted, power can be supplied from the capacitor 15 to the emergency system load 133 based on an instruction from the DCDC control unit 161 that has received a detection signal from the airbag control unit 162. Specifically, power from the capacitor 15 is supplied to the emergency system load 133 via the connection line 313, the contact 234, the resistor 19, the connection line 311, the circuit switching unit 292, the connection line 315, the DCDC converter 14, the connection line 319, the contact 235, the circuit switching unit 293, the connection line 320, the circuit switching unit 294, and the connection line 324.

[0109] Therefore, even when the power supply from the normal power supply 12 is lost due to a collision accident, the capacitor 15 can supply power to stably operate the door lock mechanism, ie, the emergency system load 133, to unlock the door and allow the occupants to escape from the vehicle.

[0110] According to the present embodiment described above, the following main effects can be achieved.

[0111] According to the vehicle power supply device 11 of this embodiment, the vehicle loads 13 are classified into a first vehicle load (e.g., steering system load 131) related to the driving of the vehicle 10 and a second vehicle load (e.g., display system load 134) unrelated to the driving of the vehicle 10. Furthermore, when the idling stop function terminates, power from either the normal power supply 12 or the DC-DC converter 14 is supplied to the first vehicle load, while power from the other is supplied to the second vehicle load. Thus, the voltage-stabilized power supplied from the DC-DC converter 14 can be supplied to either the first or second vehicle load. Consequently, when power from the DC-DC converter 14 is supplied to the first vehicle load, functions related to the driving of the vehicle 10 can operate stably. Furthermore, when power from the DC-DC converter 14 is supplied to the second vehicle load, functions unrelated to the driving of the vehicle 10, such as the display device, can operate stably. Furthermore, by classifying the loads into multiple categories and supplying the boosted power from the DC-DC converter 14 to only a portion of the loads, the capacity and structure of the DC-DC converter 14 can be simplified.

[0112] Furthermore, according to the vehicle power supply device 11 of this embodiment, when the vehicle 10 is stopped and the idle-stop function ends, the power converted by the DC-DC converter 14 is supplied to the second vehicle load. Thereafter, when the engine is restarted, the power from the capacitor 15 is supplied to the second vehicle load. This allows stable power to be supplied to the second vehicle load, such as the display system load 134, when the idle-stop function ends, allowing the second vehicle load to operate stably with minimal power. Meanwhile, when the vehicle 10 is traveling, the power converted by the DC-DC converter 14 is supplied to the first vehicle load when the idle-stop function ends. Thereafter, when the engine is restarted, the power from the capacitor 15 is supplied to the first vehicle load. This allows stable operation of the first vehicle load, such as the brake system load 132, during driving.

[0113] Furthermore, according to the vehicle power supply device 11 of this embodiment, when the vehicle 10 is traveling, at the end of the idle stop function, the power converted by the DCDC converter 14 is supplied to the brake system load 132, and thereafter, when the engine is restarted, the power from the capacitor 15 is supplied to the brake system load 132, thereby enabling the brake system load 132 to operate stably while the vehicle is traveling.

[0114] Furthermore, according to the vehicle power supply device 11 of this embodiment, during emergency operation, power is supplied from the capacitor 15 only to the third vehicle load (emergency system load 133). Therefore, even if the normal power supply 12 is damaged due to a collision accident, for example, the emergency system load 133, i.e., the third vehicle load, can be operated, allowing the occupants to escape outside the vehicle 10.

[0115] Furthermore, according to the vehicle power supply device 11 of the present embodiment, by using the display system load 134 as the second vehicle load, it is possible to suppress the display system load 134 from flickering when the idling stop function ends.

[0116] While the embodiments of the present invention have been described above, the present invention is not limited thereto and modifications can be made without departing from the spirit of the present invention.

[0117] For example, in the above embodiment, the steering system load 131 is exemplified as the first vehicle load, but either or both of the steering system load 131 and the brake system load 132 may be employed as the first vehicle load.

[0118] Furthermore, in the description with reference to Figures 4(A)-(B) and Figures 5(A)-(B), the power converted by the DCDC converter 14 is supplied to the display system load 134, and the power not converted by the DCDC converter 14 is supplied to the steering system load 131 and the braking system load 132, but the reverse may also be true.

[0119] 6(A)-(B) and 7(A)-(B), the electric power converted by the DCDC converter 14 is supplied to the brake system load 132, and the electric power not converted by the DCDC converter 14 is supplied to the steering system load 131 and the display system load 134, but the reverse may also be true.

[0120] Explanation of symbols

[0121] 10 vehicles

[0122] 11 Vehicle power supply device

[0123] 12 Normal power supply

[0124] 13 Vehicle load

[0125] 131 Steering system load

[0126] 132 Braking system load

[0127] 133 Emergency system load

[0128] 134 Display system load

[0129] 14DCDC converter

[0130] 15 capacitors

[0131] 161DCDC Control Department

[0132] 162 Airbag Control Unit

[0133] 163 Engine Control Unit

[0134] 181 diode

[0135] 182 diode

[0136] 183 diode

[0137] 184 diode

[0138] 19 resistor

[0139] 22 Launcher

[0140] 23 AC generator

[0141] 231 contacts

[0142] 232 contacts

[0143] 233 contacts

[0144] 234 contacts

[0145] 235 contacts

[0146] 236 contacts

[0147] 237 contacts

[0148] 238 contacts

[0149] 239 contacts

[0150] 240 contacts

[0151] 291 Circuit Switching Department

[0152] 292 Circuit Switching Unit

[0153] 293 Circuit Switching Unit

[0154] 294 Circuit Switching Unit

[0155] 311 connecting line

[0156] 312 connecting wire

[0157] 313 connecting wire

[0158] 315 connecting wire

[0159] 316 connecting wire

[0160] 317 connecting wire

[0161] 318 connecting wire

[0162] 319 connecting line

[0163] 320 connecting line

[0164] 321 connecting wire

[0165] 322 connecting wire

[0166] 323 connecting line

[0167] 324 connecting line

[0168] 325 connecting wire

[0169] 326 connecting wire

[0170] During A, B, C, and D.

Claims

1. A vehicle power supply device for converting electric power supplied from a normal power supply to a vehicle load in a vehicle having an idling stop function, the vehicle power supply device comprising: a power conversion circuit that converts the voltage of the power output from the normal power supply; a power storage unit connected to the power conversion circuit; as well as Operation control device, The vehicle load includes a first vehicle load that is a load related to the travel of the vehicle and a second vehicle load that is not related to the travel of the vehicle. Wherein, when the idle stop function ends, the operation control device supplying the electric power converted by the electric power conversion circuit to either the first vehicle load or the second vehicle load; supplying electric power from the normal power supply to the other of the first vehicle load and the second vehicle load, As for the operation control device, When the vehicle stops, at the end of the idle stop function, the power converted by the power conversion circuit from the normal power supply is supplied to the second vehicle load, and thereafter, when the engine is restarted, the power from the power storage unit is supplied to the second vehicle load, and When the vehicle is traveling, when the idling stop function ends, the power converted by the power conversion circuit from the normal power supply is supplied to the first vehicle load. Thereafter, when the engine is restarted, the power from the power storage unit is supplied to the first vehicle load.

2. The vehicle power supply device according to claim 1, wherein The first vehicle load includes a steering system load and a brake system load. As for the operation control device, When the vehicle is traveling, the power converted by the power conversion circuit is supplied to the brake system load when the idle stop function ends, and then, when the engine is restarted, the power from the power storage unit is supplied to the brake system load.

3. The vehicle power supply device according to claim 1 or 2, wherein: having a third vehicle load associated with an emergency maneuver of said vehicle, During the emergency operation, the calculation control device supplies electric power from the power storage unit only to the third vehicle load.

4. The vehicle power supply device according to claim 1 or 2, wherein: The second vehicle load is a display device.

5. The vehicle power supply device according to claim 3, wherein The second vehicle load is a display device.

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