Patent Application
20230415608
The present invention relates to a vehicle control system for a hybrid vehicle having different drive systems.
Conventionally, when a power source function failure occurs due to an abnormality of an in-vehicle battery during traveling of a vehicle not equipped with an automatic driving function, vehicle driving torque is lost and the traveling is switched to coasting. However, a driver of the vehicle safely stops the vehicle by operating a steering wheel. However, in a vehicle equipped with an advanced automatic driving function that does not require a steering wheel operation, when a power source function failure occurs during traveling of the vehicle, advanced automatic driving cannot be continued. Therefore, a so-called fail operation of continuing automatic driving to a road shoulder or a parking lot without causing the vehicle to become uncontrollable and of safely stopping the vehicle is required. On the other hand, electrification of vehicles is progressing against the background of exhaust gas regulations and environmental regulations for protecting the environment, and vehicles equipped with HV batteries that supply high-voltage power to drive motors of vehicles are increasing in number. Even when a power source function failure occurs due to an abnormality of an HV battery occurs, a vehicle control system that performs a fail operation is required.
As this type of vehicle control system, there is disclosed a vehicle control system including a power source circuit including a relay device capable of changing a connection state of a plurality of power sources and power source wirings, a failure detection device that detects a failure state of the relay device, a power source control device, and an automatic driving control unit, in which when the failure detection device detects that a failure corresponding to a specific failure pattern has occurred in the relay device, the automatic driving control unit performs a fail operation by limiting some control functions of the automatic driving (PTL 1).
However, the one described in PTL 1 has a problem that when a power source function failure occurs due to an abnormality of an HV battery or an in-vehicle battery, the relay device may be turned off, and the fail operation may not be performed.
An object is to provide a vehicle control system capable of implementing a fail operation while ensuring safety of traveling of a vehicle even when a power source function failure of a battery occurs.
A vehicle control system according to the present invention that solves the above problem is a vehicle control system for a hybrid vehicle having two different drive systems, the vehicle control system including: a first battery; a second battery; a relay circuit disposed on an upstream side and a downstream side of the first battery; a first DC-DC converter connected to the relay circuit; a second DC-DC converter connected to the relay circuit and connected in parallel to the first DC-DC converter; a first relay control unit that controls the relay circuit; a second relay control unit that controls the relay circuit; a first drive control unit that controls a first drive system; and a second drive control unit that controls a second drive system, wherein the first relay control unit and the first drive control unit are connected to a downstream side of the first DC-DC converter, the second relay control unit, the second battery, and the second drive control unit are connected to a downstream side of the second DC-DC converter, the first relay control unit and the second relay control unit interrupt the relay circuit on condition that an abnormality of the first battery is detected, and the second drive control unit performs control to drive the second drive system using electric power of the second battery as a power source in response to the interruption of the relay circuit.
According to the vehicle control system according to the present invention, when an abnormality is detected in the first battery, the vehicle is controlled by the second battery.
According to the present invention, it is possible to provide a vehicle control system capable of implementing a fail operation while ensuring safety of traveling of a vehicle even when a power source function failure of a battery occurs.
Further features related to the present invention will become apparent from the description of the present specification and the accompanying drawings. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.
Hereinafter, vehicle control systems 30 and 30A according to a first embodiment and a second embodiment to which a vehicle control system according to the present invention is applied, and vehicle control systems 30B and 30C according to Modification 1 and Modification 2 of the second embodiment will be described with reference to the drawings. Note that a relay circuit according to the present invention will be described by being included in the description of the vehicle control systems 30 and 30A.
The vehicle control system 30 is mounted on a vehicle that performs automatic driving. As illustrated in
The vehicle control system 30 performs a fail operation in the traveling control of the vehicle when a power source function failure such as blown fuse, overcharge abnormality, or short circuit failure occurs in any of the HV battery 1 and the in-vehicle battery 9. The HV battery 1 of the first embodiment corresponds to a first battery of the vehicle control system according to the present invention, the first high-voltage SW 2 and the second high-voltage SW 3 correspond to a relay circuit, the first high-voltage SW control unit 7 corresponds to a second relay control unit, the second high-voltage SW control unit 8 corresponds to a first relay control unit, the in-vehicle battery 9 corresponds to a second battery, the inverter control unit 10 corresponds to a first drive control unit, and the drive control unit 11 corresponds to a second drive control unit.
The HV battery 1 includes a power source that outputs high-voltage power capable of driving the motor 4 of the hybrid vehicle. The first high-voltage SW 2 that turns on or off a power source line is disposed on the upstream side, and the second high-voltage SW 3 that turns on or off a power source line is redundantly disposed on the downstream side. The operations of the first high-voltage SW 2 and the second high-voltage SW 3 are controlled by at least one of the first high-voltage SW control unit 7 and the second high-voltage SW control unit 8.
The first DC-DC converter 5 is configured to step down a high voltage output from the HV battery 1, and is connected to the first high-voltage SW 2 that is a relay circuit. The inverter control unit 10 that controls the operation of the motor 4 is connected to the downstream side of the first DC-DC converter 5, and the first high-voltage SW control unit 7 is connected to the downstream side of the inverter control unit 10.
The second DC-DC converter 6 is connected in parallel to the first DC-DC converter 5. The in-vehicle battery 9, the drive control unit 11, and the second high-voltage SW control unit 8 are connected to the downstream side of the second DC-DC converter 6. The in-vehicle battery 9 is configured similarly to a power source such as an auxiliary battery mounted on a conventional vehicle and connected to a 12 V control unit, and is configured to supply, to the drive control unit 11, electric power having a relatively low voltage, for example, 12 V, as compared with the HV battery 1. The drive control unit 11 is configured to control a drive device different from the motor 4, for example, the drive device such as the engine.
In the vehicle control system 30, for example, when an abnormality of the HV battery 1, such as blown fuse or overcharge of the HV battery 1, is detected by a control unit (abnormality detection unit) (not illustrated) that monitors the voltage of the HV battery 1, and the first high-voltage SW control unit 7 and the second high-voltage SW control unit 8 receive a control signal indicating the abnormality, the first high-voltage SW control unit 7 and the second high-voltage SW control unit 8 turn off the first high-voltage SW 2 and the second high-voltage SW 3.
As a result, electric power from the HV battery 1 is not supplied to the first DC-DC converter 5 and the second DC-DC converter 6, and the operations of the inverter control unit 10 and the first high-voltage SW control unit 7 connected to the downstream side of the first DC-DC converter 5 are not continued.
However, the in-vehicle battery 9 is disposed downstream of the second DC-DC converter 6, and the drive control unit 11 and the second high-voltage SW control unit 8 can receive power supply from the in-vehicle battery 9. Therefore, the drive device such as the engine can be operated by the control of the drive control unit 11, and the fail operation can be performed.
In addition, in the vehicle control system 30, for example, when an abnormality occurs in the in-vehicle battery 9, such as occurrence of a short failure of the in-vehicle battery 9, electric power is not supplied from the in-vehicle battery 9 to the drive control unit 11, and the drive device such as the engine cannot be driven. In addition, electric power is also not supplied to the second high-voltage SW control unit 8, and the relay circuit cannot be controlled by the second high-voltage SW control unit 8.
However, even when an abnormality occurs in the in-vehicle battery 9, the power source lines connected from the HV battery 1 to the first DC-DC converter 5 and the second DC-DC converter 6 are conductive. Therefore, the control of the relay circuit by the first high-voltage SW control unit 7 is performed without any trouble, and the first high-voltage SW 2 and the second high-voltage SW 3 are maintained in the ON state.
Therefore, the inverter control unit 10 controls the driving of the motor 4 with electric power supplied from the HV battery 1, and performs a fallback of maintaining the operation in a state where the function and performance of the system are partially stopped, whereby the fail operation can be performed. Note that the specific content of operation control in the fallback is not particularly limited as long as the fail operation can be performed.
Although the case where the abnormality occurs in the in-vehicle battery 9 has been described, the fail operation by the fallback can be performed similarly to the case where the abnormality occurs in the in-vehicle battery 9 even when an abnormality, such as a short-circuit failure of the output of the second DC-DC converter 6 or disconnection of the power source line of the in-vehicle battery 9, occurs in the power source line including the second DC-DC converter 6 and the in-vehicle battery 9.
The vehicle control system 30 can also perform control to stop the interruption of the first high-voltage SW 2 and the second high-voltage SW 3 by the second relay control unit and connect the first high-voltage SW 2 and the second high-voltage SW 3 again on condition that a start signal to start the hybrid vehicle is received.
An effect of the vehicle control system 30 of the first embodiment will be described.
As illustrated in
That is, in the vehicle control system 30, the first high-voltage SW control unit 7 and the second high-voltage SW control unit 8 that respectively control the first high-voltage SW 2 on the upstream side of the HV battery 1 and the second high-voltage SW 3 on the downstream side of the HV battery 1 are redundantly arranged downstream of the first DC-DC converter 5 and the second DC-DC converter 6, respectively. The vehicle control system 30 includes the two power source lines. Further, the in-vehicle battery 9 and the drive control unit 11 are disposed on the same power source line.
With this configuration, when an abnormality occurs in the HV battery 1, the drive control unit 11 and the second high-voltage SW control unit 8 can receive power supply from the in-vehicle battery 9. As a result, the drive device such as the engine can be operated by the control of the drive control unit 11, and the effect that the fail operation can be performed while the safety of traveling is secured can be obtained.
In addition, even in a case where an abnormality occurs in the in-vehicle battery 9, since the power source line connected from the HV battery 1 to the first DC-DC converter 5 is conductive, it is possible to obtain the effect that the inverter control unit 10 can control the driving of the motor 4 with electric power supplied from the HV battery 1, and that it is possible to perform the fail operation while ensuring the safety of traveling.
As described above, the vehicle control system 30 according to the first embodiment includes the respective components illustrated in
The vehicle control system 30A according to the second embodiment is mounted on a vehicle that performs automatic driving. As illustrated in
A load Rf 17 for a fail operation, another load Rx 18, an inverter control unit 10, and a first high-voltage SW control unit 7 are connected downstream of a first DC-DC converter 5. A load Rf 17 for the fail operation, another load Rx 18, a starter 19, an engine control unit 20, and a second high-voltage SW control unit 8 are connected downstream of a second DC-DC converter 6.
Similarly to the vehicle control system 30 according to the first embodiment, the vehicle is a hybrid vehicle including a drive device such as an engine (not illustrated) and a motor 4 as power sources. The first high-voltage relay 12 of the second embodiment corresponds to a first relay of the vehicle control system according to the present invention, the second high-voltage relay 13 corresponds to a third relay, the third high-voltage relay 14 corresponds to a second relay, and the fourth high-voltage relay 15 corresponds to a fourth relay.
The first high-voltage relay 12 and the third high-voltage relay 14 that turn on or off a power source line are disposed on the upstream side of the HV battery 1, and the second high-voltage relay 13 and the fourth high-voltage relay 15 that turn on or off a power source line are disposed on the downstream side of the HV battery 1.
The operations of the first high-voltage relay 12 and the second high-voltage relay 13 (A and B illustrated in
The first DC-DC converter 5 is configured to step down a high voltage output from the HV battery 1, and is connected to the first high-voltage relay 12 and the third high-voltage relay 14. The load Rf 17 for the fail operation, the other load Rx 18 arbitrarily arranged, and the inverter control unit 10 are connected to the downstream side of the first DC-DC converter 5, and the first high-voltage SW control unit 7 is connected to the downstream side of the inverter control unit 10.
An in-vehicle battery 9 is not disposed on the downstream side of the first DC-DC converter 5, and there is a concern such as a voltage drop with respect to a transient load increase in the load Rf 17 for the fail operation. Therefore, it is preferable to perform a fallback at the time of the fail operation with respect to the load on the downstream side of the first DC-DC converter 5. Examples of the fallback at the time of the fail operation include suppressing motor torque (N·m) at the time of power steering control.
The second DC-DC converter 6 is connected in parallel to the first DC-DC converter 5. The in-vehicle battery 9, the load Rf 17 for the fail operation, the load Rx 18 arbitrarily arranged, the starter 19, the engine control unit 20, a load Rs 16 requiring standby, and the second high-voltage SW control unit 8 are connected to the downstream side of the second DC-DC converter 6.
The load Rs 16 requiring standby is a load that receives an ignition key signal and permits electric power to be supplied from the in-vehicle battery 9 and the second DC-DC converter 6 to the in-vehicle devices, and specific examples thereof include loads such as a smart key control Assy and a body control unit (body control modules (BCMs)) that monitor a body of the vehicle and functions such as security. Specific examples of the load Rf 17 for the fail operation include power steering control and automatic driving control.
The starter 19 is a motor for starting the vehicle. In the hybrid vehicle, the starter 19 may be used when the HV battery 1 fails. For example, it is used to drive a drive system of the vehicle by the starter 19 to move the vehicle from a traveling lane to a road shoulder. The engine control unit 20 is configured to control the operation of the engine (not illustrated).
Each of the first high-voltage SW control unit 7 and the second high-voltage SW control unit 8 includes a microcomputer, and has a function of detecting a failure such as sticking or disconnection of the first high-voltage relay 12, the second high-voltage relay 13, the third high-voltage relay 14, and the fourth high-voltage relay 15. When the contact of each relay is changed from the interruption state to the conduction state, large inrush current to a capacitor may cause welding or sticking to the contact of each relay or disconnection of each relay. The first high-voltage SW control unit 7 and the second high-voltage SW control unit 8 can detect these failures.
The first high-voltage SW control unit 7 and the second high-voltage SW control unit 8 diagnose these failures before the start of the vehicle, and take appropriate measures at the time of abnormality. The first high-voltage relay 12 and the third high-voltage relay 14 are redundantly disposed on the upstream side of the HV battery 1, the second high-voltage relay 13 and the fourth high-voltage relay 15 are redundantly disposed on the downstream side of the HV battery 1. The first high-voltage relay 12 and the third high-voltage relay 14, and the second high-voltage relay 13 and the fourth high-voltage relay 15 are configured to reliably disconnect the HV battery 1 from the power source lines even when any one of the high-voltage relays has a sticking failure.
Further, a monitoring function is implemented in the microcomputers mounted in the first high-voltage SW control unit 7 and the second high-voltage SW control unit 8. When an abnormality such as program runaway of the microcomputers occurs, the first high-voltage SW control unit 7 and the second high-voltage SW control unit 8 are configured to turn off each of the high-voltage relays by the monitoring functions.
Next, a procedure for starting the vehicle by the vehicle control system 30A according to the second embodiment will be briefly described.
First, when the load Rs 16 requiring standby such as a standby state of the vehicle receives a key-on signal, electric power is supplied from the in-vehicle battery 9 to the second high-voltage SW control unit 8. The first high-voltage relay 12 and the second high-voltage relay 13 are turned on by the second high-voltage SW control unit 8, and the first DC-DC converter 5 and the second DC-DC converter 6 can be activated. Then, electric power is supplied from the first DC-DC converter 5 to the first high-voltage SW control unit 7. The third high-voltage relay 14 and the fourth high-voltage relay 15 are turned on by the first high-voltage SW control unit 7, and the vehicle can start by the driving force of the motor 4.
Here, during normal operation, the first high-voltage SW control unit 7 does not necessarily turn on the third high-voltage relay 14 and the third high-voltage relay 15 (C and D illustrated in
A procedure when an abnormality occurs in the HV battery 1 according to the second embodiment will be described. For example, when an overcharge abnormality occurs in the HV battery 1, the first high-voltage SW control unit 7 and the second high-voltage SW control unit 8 receive an abnormality notification signal from a control unit that monitors the voltage of the HV battery 1. The first high-voltage SW control unit 7 and the second high-voltage SW control unit 8 turn off all of the first high-voltage relay 12 and the second high-voltage relay 13 (A and B illustrated in
When all of A, B, C, and D illustrated in
Conventionally, when a voltage abnormality occurs in an HV battery 1, there is a risk that the HV battery 1 overheats. Therefore, there is a demand for immediately turning off each high-voltage relay to implement fail safe. In addition, when the HV battery 1 comes into contact with the body due to a vehicle accident or the like, there is a possibility that electricity flows to the body. Therefore, there is a demand for implementing fail safe by immediately turning off each high-voltage relay after receiving a failure notification signal from an airbag. In response to such a request, it is possible to satisfy a conventional request for fail safe by the vehicle control of the vehicle control system 30A according to the second embodiment.
A procedure when an abnormality occurs in the in-vehicle battery 9 according to the second embodiment will be described. For example, when a short-circuit failure occurs in the in-vehicle battery 9, electric power is not supplied to the engine control unit 20, and the engine cannot be driven by power supply from the in-vehicle battery 9.
Electric power is not supplied to the second high-voltage SW control unit 8 either, and the first high-voltage relay 12 and the second high-voltage relay 13 (A and B illustrated in
Although the abnormality of the in-vehicle battery 9 has been described in the example described above, the fail operation according to the procedure when the abnormality occurs in the in-vehicle battery 9 is similarly performed for an abnormality of a power source network including the second DC-DC converter 6 and the in-vehicle battery 9, such as the short-circuit failure of the output of the second DC-DC converter 6 or the disconnection of the power source line of the in-vehicle battery 9.
When the in-vehicle battery 9 and the HV battery 1 are normal, the first high-voltage relay 12 and the second high-voltage relay 13 (A and B illustrated in
An effect of the vehicle control system 30A according to the second embodiment will be described.
As illustrated in
That is, in the vehicle control system 30A, the first high-voltage SW control unit 7 and the second high-voltage SW control unit 8 that respectively control the first high-voltage relay 12 and the third high-voltage relay 14 on the upstream side of the HV battery 1 and the second high-voltage relay 13 and the fourth high-voltage relay 15 on the downstream side of the HV battery 1 are redundantly arranged downstream of the first DC-DC converter 5 and the second DC-DC converter 6, and the vehicle control system includes the two power source lines. Further, the in-vehicle battery 9, the starter 19, and the engine control unit 20 are disposed on the same power source line. With this configuration, even when an abnormality occurs in the in-vehicle battery 9, since the power source line connected from the HV battery 1 to the first DC-DC converter 5 is conductive, it is possible to obtain the effect that the inverter control unit 10 can perform the drive control of the motor 4 by using electric power supplied from the HV battery 1, and that it is possible to perform the fail operation while ensuring the safety of traveling.
When an abnormality occurs in the HV battery 1, the in-vehicle battery 9 is disposed downstream of the second DC-DC converter 6, and the starter 19, the engine control unit 20, and the second high-voltage SW control unit 8 can receive power supply from the in-vehicle battery 9. As a result, it is possible to operate the engine by the control of the engine control unit 20, and it is possible to obtain the effect of performing the fail operation while ensuring the safety of traveling.
As described above, the vehicle control system 30A according to the second embodiment includes the respective components illustrated in
(Modification 1)
As illustrated in
The first high-voltage relay 12 is branched into A and C illustrated in
Also with this configuration, effects similar to those of the vehicle control system 30A according to the second embodiment can be obtained. That is, even when a power source function failure of the HV battery 1 or the in-vehicle battery 9 occurs, it is possible to obtain the effect that the fail operation can be implemented while ensuring the safety of the traveling of the vehicle. In this configuration, for example, when a short-circuit failure occurs in the in-vehicle battery 9, a SW for disconnection is required so that the power source of the first high-voltage relay 12 and the second high-voltage relay 13 does not decrease.
(Modification 2)
As illustrated in
Specifically, as illustrated in
The vehicle control system 30C according to Modification 2 can obtain the same effects as those of the vehicle control system 30A according to the second embodiment. That is, even when a power source function failure of the HV battery 1 or the in-vehicle battery 9 occurs, it is possible to obtain the effect that the fail operation can be implemented while ensuring the safety of the traveling of the vehicle.
Although the first embodiment and the second embodiment of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the gist of the present invention described in the claims. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the described configurations. In addition, a part of the configuration of a certain embodiment can be replaced with the configuration of another embodiment, and the configuration of a certain embodiment can be added to the configuration of another embodiment. In addition, for a part of the configuration of each embodiment, it is possible to add, delete, and replace another configuration.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-030596 | Feb 2021 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2021/035462 | 9/27/2021 | WO |
