Vehicle-mounted control device

Abstract

Provided is a vehicle-mounted control device that is capable of reliably supplying power to a load which must be operated upon vehicle collision.　A vehicle-mounted control device (10) is included in a vehicle-mounted system (100). The vehicle-mounted control device (10) comprises: a first switch unit (30) that is provided in a first branching path (55) between a second power path (52) and a first load (70); and a control unit (34) that, upon receipt of a collision detection signal (Cs), controls the first switch unit (30) to the off state.

Description

In-vehicle control device

[0001] The present disclosure relates to an in-vehicle control device.

[0002] Patent Document 1 discloses a technology for predicting a collision based on the output of an obstacle detection sensor that detects obstacles around the vehicle, and for reliably supplying power to equipment necessary for passenger protection.

[0003] Japanese Patent Application Laid-Open No. 2003-165406

[0004] Patent Document 1 discloses a configuration in which a single battery supplies power to all loads in the first to third groups. Therefore, the configuration of Patent Document 1 requires a larger battery to ensure sufficient power to supply each load. Furthermore, in vehicles with a high-voltage battery, voltage-converted power is supplied from the high-voltage battery to each load, but the high-voltage battery is shut off when the vehicle collides. In this case, even if the vehicle also has a low-voltage battery, the low-voltage battery alone may not be able to supply power to the loads that need to be operated when the vehicle collides. Therefore, there is a demand for technology that can prioritize power supply to high-priority loads when a collision is detected.

[0005] The present disclosure has been made based on the above-mentioned circumstances, and aims to provide an in-vehicle control device that can reliably supply power to a load that needs to be operated when a vehicle collides.

[0006] The vehicle control device disclosed herein includes: a high-voltage battery; a voltage conversion unit; a low-voltage battery; a first power path provided between the high-voltage battery and the voltage conversion unit; a second power path provided between the voltage conversion unit and the low-voltage battery; a relay provided on the first power path; a relay control unit that switches the relay to an off state when a vehicle collision is detected; an output unit that outputs a collision detection signal when a vehicle collision is detected; a first branch path branching from the second power path; a first load electrically connected to the first branch path; a second branch path branching from the second power path; and a second load electrically connected to the second branch path, wherein the voltage conversion unit is an vehicle control device included in an vehicle system that steps down a voltage input from the first power path side and outputs the voltage input to the second power path side; and the voltage conversion unit has: a first switch unit provided in the first branch path between the second power path and the first load; and a control unit that controls the first switch unit to an off state when the collision detection signal is received.

[0007] According to the present disclosure, it is possible to reliably supply power to a load that needs to be operated when a vehicle crashes.

[0008] Fig. 1 is a circuit diagram showing the configuration of an in-vehicle system according to embodiment 1. Fig. 2 is a table showing the states of each switch unit during parking, driving, and in the event of a collision. Fig. 3 is a flowchart showing an example of control in the control unit.

[0009] [Description of Embodiments of the Present Disclosure] In the following, embodiments of the present disclosure are listed and illustrated.

[0010] (1) An on-board control device included in an on-board system comprising: a high-voltage battery; a voltage conversion unit; a low-voltage battery; a first power path provided between the high-voltage battery and the voltage conversion unit; a second power path provided between the voltage conversion unit and the low-voltage battery; a relay provided on the first power path; a relay control unit that switches the relay to an off state when a vehicle collision is detected; an output unit that outputs a collision detection signal when a vehicle collision is detected; a first branch path branching from the second power path; a first load electrically connected to the first branch path; a second branch path branching from the second power path; and a second load electrically connected to the second branch path, wherein the voltage conversion unit steps down a voltage input from the first power path and outputs the voltage to the second power path, the on-board control device having: a first switch unit provided in the first branch path between the second power path and the first load; and a control unit that controls the first switch unit to an off state when the collision detection signal is received.

[0011] (1) The vehicle control device sets a load that is not necessary for the vehicle to run as the first load and a load that is necessary for the vehicle to run as the second load, thereby making it possible to configure the device to supply power intensively to the second load when the vehicle collides.

[0012] (2) The vehicle control device described in (1), wherein when the control unit receives the collision detection signal, the control unit confirms that the output of the voltage conversion unit has stopped and then controls the first switch unit to an off state.

[0013] (2) In the case where a collision detection signal is output even though the vehicle has not collided, the vehicle control device confirms that the output of the voltage conversion unit has stopped and then turns off the first switch unit, thereby preventing the power to the first load from being inadvertently cut off.

[0014] (3) The vehicle control device according to (1) or (2), further comprising a second switch unit provided in the second branch path between the second power path and the second load, wherein the control unit controls the first switch unit to an off state and maintains the second switch unit in an on state when the collision detection signal is received.

[0015] (3) The vehicle control device can prevent power from being supplied from the low-voltage battery to the first load by turning off the first switch unit during a collision, while supplying power from the low-voltage battery to the second load by maintaining the second switch unit in the on state.

[0016] (4) An in-vehicle control device according to any one of (1) to (3), further comprising a third switch unit arranged on the second power path closer to the voltage conversion unit than the first load and the second load, wherein the control unit controls the first switch unit and the third switch unit to an off state when the control unit receives the collision detection signal.

[0017] (4) In the case where the voltage conversion unit itself fails (such as due to a short circuit), the on-board control device can prevent the output voltage of the low-voltage battery from being reduced by the failed voltage conversion unit.

[0018] 1 is a system mounted on a vehicle. The vehicle system 100 includes a high-voltage battery 90, a voltage conversion unit 92, a low-voltage battery 91, a first power path 50, a relay 51, a second power path 52, an output unit 53, a relay control unit 54, a first branch path 55, a second branch path 56, a first load 70, and a second load 71. The vehicle system 100 further includes an in-vehicle control device 10. The vehicle system 100 supplies power based on the high-voltage battery 90 and the low-voltage battery 91 to the first load 70 and the second load 71.

[0019] The high-voltage battery 90 is, for example, an assembled battery configured by combining multiple unit cells such as lithium-ion batteries or nickel-metal hydride batteries in series, and outputs an output voltage of, for example, about 400 V. The voltage conversion unit 92 is a known DC-DC converter that can step down the voltage input from the high-voltage battery 90 side (first power path 50 side) and output it to the second power path 52 side. The low-voltage battery 91 can be, for example, a lead-acid battery or a configuration using the same type of unit cells as the high-voltage battery 90, with fewer cells connected in series than the high-voltage battery 90. For example, the low-voltage battery 91 can output an output voltage of about 12 V.

[0020] The first power path 50 is provided between the high-voltage battery 90 and the voltage conversion unit 92. The relay 51 is a so-called system main relay, and is, for example, a mechanical relay switch. The relay 51 is provided on the first power path 50. The second power path 52 is provided between the voltage conversion unit 92 and the low-voltage battery 91.

[0021] The output unit 53 and the relay control unit 54 are configured, for example, as separate ECUs (Electronic Control Units), each including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc. The output unit 53 is, for example, an ECU that controls the operation of an airbag (not shown). A collision detection sensor 53A is electrically connected to the output unit 53. A known sensor, such as a satellite sensor, is used as the collision detection sensor 53A. For example, the collision detection sensor 53A is configured to output a voltage signal S corresponding to the acceleration of the vehicle to the output unit 53. When the vehicle collides or is hit, the acceleration of the vehicle changes rapidly in a short period of time. Therefore, the magnitude of the signal S output from the collision detection sensor 53A changes rapidly when the vehicle collides or is hit. When the signal S changes suddenly, the output unit 53 determines that the vehicle has collided or has been collided, and activates the airbag. At the same time, the output unit 53 outputs a collision detection signal Cs to the relay control unit 54 and the control unit 34, which will be described later. In other words, the output unit 53 outputs the collision detection signal Cs when it detects that the vehicle has collided or has been collided.

[0022] In the present disclosure, "electrically connected" preferably refers to a configuration in which the connection targets are connected in a mutually conductive state (a state in which a current can flow) so that the potentials of both connection targets are equal. However, this configuration is not limited to this. For example, "electrically connected" may also refer to a configuration in which the connection targets are connected in a state in which the two connection targets can be electrically connected with an electrical component interposed between them.

[0023] The relay control unit 54 controls the operation of the relay 51. For example, the relay control unit 54 keeps the relay 51 in the ON state while a start switch (not shown) of the vehicle is in the ON state. When a collision detection signal Cs indicating that the vehicle is colliding or has been collided is input while the start switch of the vehicle is in the ON state, the relay control unit 54 switches the relay 51 from the ON state to the OFF state.

[0024] The first branch path 55 is provided by branching off from the second power path 52. The second branch path 56 is provided by branching off from the second power path 52.

[0025] The first load 70 is electrically connected to the first branch path 55. The first load 70 is electrically connected to the second power path 52 via the first branch path 55. The first load 70 is, for example, a load that does not affect the safety of the vehicle even if it does not operate while the vehicle is running, and corresponds to, for example, a seat heater or a USB power source. Here, the state in which the vehicle is running refers to a state in which the start switch of the vehicle is on and the vehicle speed is greater than 0. The state in which the start switch of the vehicle is on and the vehicle speed is 0 refers to a state in which the vehicle is stopped.

[0026] The second load 71 is electrically connected to the second branch path 56. The second load 71 is electrically connected to the second power path 52 via the second branch path 56. The second load 71 is a load that may affect the safety of the vehicle and is a load that is more important than the first load 70. The importance is determined based on the functional safety level defined in ISO 26262, for example. The second load 71 corresponds to, for example, an ECU of an electric brake device, an ECU of a shift-by-wire device, an ECU of a door lock device, a display device, an ECU of an airbag device, a DCM (Data Communication Module), etc.

[0027] [Configuration of the Vehicle Control Device] The vehicle control device 10 includes, for example, a first switch unit 30, a second switch unit 33, a third switch unit 31, a fourth switch unit 32, and a control unit 34. The first switch unit 30 is provided in the first branch path 55 between the second power path 52 and the first load 70. The second switch unit 33 is provided in the second branch path 56 between the second power path 52 and the second load 71. The third switch unit 31 is provided in the second power path 52 closer to the voltage conversion unit 92 than the first branch path 55 to which the first load 70 is electrically connected and the second branch path 56 to which the second load 71 is electrically connected. The fourth switch unit 32 is provided in the second power path 52 closer to the low-voltage battery 91 than the first branch path 55 to which the first load 70 is electrically connected and the second branch path 56 to which the second load 71 is electrically connected. Each of the first switch section 30, the second switch section 33, the third switch section 31, and the fourth switch section 32 uses a switching element such as a field effect transistor (FET).

[0028] A voltage detection unit 57 is provided on the second power path 52 between the third switch unit 31 and the voltage conversion unit 92. The voltage detection unit 57 is configured to be able to output a voltage signal Vs, which is the output voltage of the voltage conversion unit 92 and corresponds to the voltage of the second power path 52, to the control unit 34.

[0029] The control unit 34 is configured as, for example, an ECU and includes a CPU, a ROM, a RAM, etc. The control unit 34 is configured to receive a collision detection signal Cs from the output unit 53 and a voltage signal Vs from the voltage detection unit 57. Based on the collision detection signal Cs and the voltage signal Vs, the control unit 34 can control the driving of each of the first switch unit 30, the second switch unit 33, the third switch unit 31, and the fourth switch unit 32 to switch them to either an ON state or an OFF state.

[0030] [Example of Operation of the In-Vehicle Control Device] Next, a description will be given of an example of operation of the in-vehicle control device 10. As shown in Fig. 2, for example, when a vehicle equipped with the in-vehicle system 100 is parked, the first switch unit 30, the second switch unit 33, the third switch unit 31, and the fourth switch unit 32 are each controlled by the control unit 34 to be maintained in an ON state. Here, the state in which the vehicle is parked corresponds to the state in which the start switch of the vehicle is in an OFF state.

[0031] When the vehicle equipped with the in-vehicle system 100 is traveling, the first switch unit 30, the second switch unit 33, the third switch unit 31, and the fourth switch unit 32 are each controlled by the control unit 34 to be maintained in the ON state. Even when the vehicle is stopped, the first switch unit 30, the second switch unit 33, the third switch unit 31, and the fourth switch unit 32 may be controlled by the control unit 34 to be maintained in the ON state. The control unit 34 monitors whether a collision detection signal Cs is input while the vehicle is traveling. The control unit 34 receives a voltage signal Vs, which is an output voltage from the voltage conversion unit 92 and corresponds to the voltage of the second power path 52.

[0032] The collision detection sensor 53A outputs a voltage signal S corresponding to the acceleration of the vehicle to the output unit 53. For example, when the vehicle collides or is hit and the magnitude of the signal S output from the collision detection sensor 53A changes suddenly, the output unit 53 determines that the vehicle has collided or been hit, and outputs a collision detection signal Cs to each of the relay control unit 54 and the control unit 34. When the collision detection signal Cs is input, the relay control unit 54 executes control to switch the relay 51 from an on state to an off state.

[0033] The operation of the control unit 34 will be described with reference to FIG. 3 and other figures. When the control unit 34 receives the collision detection signal Cs (Yes in step S1), the control unit 34 proceeds to step S2 and determines whether the output from the voltage conversion unit 92 has stopped. Specifically, when the control unit 34 receives the collision detection signal Cs, the control unit 34 determines whether the voltage signal Vs is equal to or less than the voltage threshold. The voltage threshold is set, for example, to a value corresponding to a state in which no voltage is being output from the voltage conversion unit 92 and is stored in a ROM or the like of the control unit 34. When the control unit 34 receives the collision detection signal Cs and determines that the voltage signal Vs is equal to or less than the voltage threshold (Yes in step S2) (i.e., after confirming that the output from the voltage conversion unit 92 has stopped), the control unit 34 proceeds to step S3. When the control unit 34 proceeds to step S3, the control unit 34 switches the first switch unit 30 and the third switch unit 31 from the ON state to the OFF state and maintains the fourth switch unit 32 and the second switch unit 33 in the ON state (see FIG. 2).

[0034] If the control unit 34 does not receive the collision detection signal Cs (No in step S1), it ends the process shown in Fig. 3 and executes the process shown in Fig. 3 again. If the control unit 34 determines that the output from the voltage conversion unit 92 has not stopped, that is, that the voltage signal Vs is greater than the voltage threshold value (No in step S2), it ends the process shown in Fig. 3 and executes the process shown in Fig. 3 again.

[0035] Next, the effects of this configuration will be illustrated. The on-board control device 10 is included in an on-board system 100. The on-board system 100 includes a high-voltage battery 90, a voltage conversion unit 92, a low-voltage battery 91, a first power path 50 provided between the high-voltage battery 90 and the voltage conversion unit 92, a second power path 52 provided between the voltage conversion unit 92 and the low-voltage battery 91, a relay 51 provided on the first power path 50, a relay control unit 54 that switches the relay 51 to an off state when a vehicle collision or a collision occurrence is detected, an output unit 53 that outputs a collision detection signal Cs when a vehicle collision or a collision occurrence is detected, a first branch path 55 branching from the second power path 52, a first load 70 electrically connected to the first branch path 55, a second branch path 56 branching from the second power path 52, and a second load 71 electrically connected to the second branch path 56. The voltage conversion unit 92 steps down the voltage input from the first power path 50 and outputs the stepped down voltage to the second power path 52. The on-board control device 10 includes a first switch unit 30 provided in the first branch path 55 between the second power path 52 and the first load 70, and a control unit 34 that controls the first switch unit 30 to an off state when a collision detection signal Cs is received.

[0036] According to this configuration, by setting a load that is unnecessary for the vehicle to run as the first load 70 and a load that is necessary for the vehicle to run as the second load 71, it becomes possible to configure the system so that power is supplied intensively to the second load 71 when the vehicle collides or is hit.

[0037] When the control unit 34 receives the collision detection signal Cs, the control unit 34 confirms that the output of the voltage conversion unit 92 has stopped, and then controls the first switch unit 30 to the OFF state. According to this configuration, in a case where the collision detection signal Cs is output even though the vehicle has collided or has not been collided, the control unit 34 confirms that the output of the voltage conversion unit 92 has stopped, and then controls the first switch unit 30 to the OFF state, thereby preventing the power to the first load 70 from being inadvertently stopped.

[0038] The on-board control device 10 has a second switch unit 33 provided in the second branch path 56 between the second power path 52 and the second load 71. When the control unit 34 receives the collision detection signal Cs, it controls the first switch unit 30 to an OFF state and maintains the second switch unit 33 in an ON state. With this configuration, in the event of a collision, turning the first switch unit 30 to an OFF state prevents power from being supplied from the low-voltage battery 91 to the first load 70, while maintaining the second switch unit 33 in an ON state allows power to be supplied from the low-voltage battery 91 to the second load 71.

[0039] The on-board control device 10 has a third switch unit 31 that is disposed closer to the voltage conversion unit 92 than the first load 70 and the second load 71 in the second power path 52. When the control unit 34 receives a collision detection signal Cs, it controls the first switch unit 30 and the third switch unit 31 to the off state. With this configuration, if the voltage conversion unit 92 itself fails (such as due to a short circuit), it is possible to prevent the output voltage of the low-voltage battery 91 from being reduced by the failed voltage conversion unit 92.

[0040] <Other Embodiments> The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is not limited to the embodiments disclosed herein, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0041] In each switch section, the switching elements may be arranged in series with each other and in opposite directions. Specifically, a pair of switching elements may be arranged so that the anodes or cathodes of the body diodes of each element face each other. Alternatively, each switch section may use one FET. Alternatively, a switch section may have a combination of a pair of FETs and a single FET.

[0042] Unlike the above embodiment, each switch unit may be controlled only by a collision detection signal without using a voltage signal.

[0043] Unlike the above embodiment, the control unit may be configured to monitor the drive signals that drive each switching element of the voltage conversion unit, and determine that the output of the voltage conversion unit has stopped based on these drive signals.

[0044] Unlike the above embodiment, the process shown in FIG. 3 may be performed when the vehicle is stopped.

[0045] In the above embodiment, the vehicle control device has four switch sections: the first switch section, the third switch section, the fourth switch section, and the second switch section, but it is sufficient if it has at least the first switch section.

[0046] 10: Vehicle control device 30: First switch section 31: Third switch section 32: Fourth switch section 33: Second switch section 34: Control section 50: First power path 51: Relay 52: Second power path 53: Output section 53A: Collision detection sensor 54: Relay control section 55: First branch path 56: Second branch path 57: Voltage detection section 70: First load 71: Second load 90: High-voltage battery 91: Low-voltage battery 92: Voltage conversion section 100: Vehicle system Cs: Collision detection signal S: Signal Vs: Voltage signal

Claims

1. An on-board control device included in an on-board system comprising: a high-voltage battery, a voltage conversion unit, a low-voltage battery, a first power path provided between the high-voltage battery and the voltage conversion unit, a second power path provided between the voltage conversion unit and the low-voltage battery, a relay provided on the first power path, a relay control unit that switches the relay to an off state when a vehicle collision is detected, an output unit that outputs a collision detection signal when a vehicle collision is detected, a first branch path branching from the second power path, a first load electrically connected to the first branch path, a second branch path branching from the second power path, and a second load electrically connected to the second branch path, wherein the voltage conversion unit steps down a voltage input from the first power path and outputs it to the second power path, the on-board control device having: a first switch unit provided in the first branch path between the second power path and the first load; and a control unit that controls the first switch unit to an off state when the collision detection signal is received.

2. The vehicle control device according to claim 1, wherein, when the control unit receives the collision detection signal, the control unit confirms that the output of the voltage conversion unit has stopped, and then controls the first switch unit to an off state.

3. An on-vehicle control device as described in claim 1 or claim 2, wherein the second branch path has a second switch unit provided between the second power path and the second load, and the control unit controls the first switch unit to an off state and maintains the second switch unit in an on state when the collision detection signal is received.

4. An in-vehicle control device as described in claim 1 or claim 2, further comprising a third switch unit arranged on the second power path closer to the voltage conversion unit than the first load and the second load, and wherein the control unit controls the first switch unit and the third switch unit to an off state when the collision detection signal is received.

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