JP7629694B2 - Vehicle control device - Google Patents

Description

The present invention relates to a vehicle control device.

A system that realizes advanced driving assistance when an abnormality occurs in the main power supply has been known (Patent Document 1). The invention described in Patent Document 1 operates an electrical load that realizes the advanced driving assistance system when an abnormality occurs in the main power supply using power supplied from a sub-power supply.

JP 2017-218013 A

However, the invention described in Patent Document 1 does not take into consideration what happens if an abnormality occurs in the sub-power source (auxiliary battery).

The present invention was made in consideration of the above problems, and its purpose is to provide a vehicle control device that can maintain the system functions even if an abnormality occurs in the auxiliary battery.

A vehicle control device according to one aspect of the present invention includes a DC-DC converter, a switching device, a first auxiliary battery and a first controller connected between the DC-DC converter and the switching device, and a second auxiliary battery and a second controller connected to the DC-DC converter via the switching device. The first controller has a function of starting the vehicle.

According to the present invention, the system can function even if an abnormality occurs in the auxiliary battery.

FIG. 1 is a block diagram of a vehicle control device 1 according to an embodiment of the present invention.

Embodiments of the present invention will be described below with reference to the drawings. In the description of the drawings, identical parts are given the same reference numerals and the description will be omitted.

As shown in FIG. 1, the vehicle control device 1 includes a drive battery 10, a DCDC converter 11, an auxiliary battery 12 (first auxiliary battery), a first controller 13, a switching device 14, a relay 15, an auxiliary battery 16 (second auxiliary battery), and a second controller 17.

The vehicle control device 1 is mounted on a vehicle equipped with an automatic driving function. In this embodiment, the automatic driving is described as a case in which all operations related to acceleration, steering, and deceleration are performed automatically, regardless of user operation, but is not limited to this. The automatic driving may be a case in which at least two operations related to acceleration, steering, and deceleration are performed automatically, and the remaining operations are performed by the user. Alternatively, the automatic driving may be a case in which at least one operation related to acceleration, steering, and deceleration is performed automatically, and the remaining operations are performed by the user.

The driving battery 10 is a driving battery that is mainly used as a power source for a motor (not shown). The driving battery 10 is a large-capacity secondary battery composed of multiple battery modules. The driving battery 10 is sometimes called a high-power battery.

A DC-DC converter 11 is connected between the driving battery 10 and the switching device 14. The DC-DC converter 11 steps down the power of the driving battery 10 and supplies the power to the auxiliary battery 12 and the auxiliary battery 16. The arrows in FIG. 1 indicate the direction in which power is supplied.

The auxiliary battery 12 and the first controller 13 are connected between the DCDC converter 11 and the switching device 14. The auxiliary battery 12 is used as a power source for electrical equipment mounted on the vehicle. The auxiliary battery 12 is a lead acid battery (LAB) that operates at a voltage of 12V to 15V. Examples of electrical equipment to which the auxiliary battery 12 supplies power include a navigation device and an audio device. The auxiliary battery 12 also supplies power to the first controller 13 as well as to the electrical equipment.

The first controller 13 is a so-called ECU (Electronic Control Unit), and is an electronic control unit having a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc. Various functions are realized by executing software embedded in the first controller 13.

One of the functions is the function of starting the vehicle. Specifically, the first controller 13 has a function of starting the vehicle when it receives a signal transmitted from an intelligence key carried by the user before the user gets in the vehicle. Starting up here means, for example, making electrical equipment available for use. By starting up the vehicle before the user gets in the vehicle, the user can use the navigation device, audio device, and the like immediately after getting in. Note that starting up the vehicle using a signal transmitted from an intelligence key is sometimes called AUTOACC.

The definition of "start" is not limited to the above. Starting a vehicle may be defined as putting the vehicle in a state where it can be driven. When a user presses the power switch while depressing the brake pedal, a specific signal is sent to the first controller 13. The first controller 13 receiving this signal puts the vehicle in a state where it can be driven. Note that the first controller 13 has a function of maintaining the started state.

Other functions include controlling electrical equipment. Specifically, the first controller 13 has the function of controlling a navigation device, an audio device, etc. in response to user input.

Another function is an automatic driving function. Specifically, the first controller 13 has a function of controlling various actuators such as an accelerator actuator, a steering actuator, and a brake actuator using information acquired by a camera or the like so that the vehicle travels automatically along a preset route. This realizes automatic driving. Note that the first controller 13 may have at least one of the functions of automatically accelerating and decelerating the vehicle or automatically steering the vehicle.

Another function is an emergency stop function. Specifically, if the first controller 13 detects any abnormality, it has the function of setting a route different from the pre-set route and automatically stopping the vehicle on the side of the road, etc.

As shown in FIG. 1, the auxiliary battery 16 and the second controller 17 are connected to the DCDC converter 11 via the switching device 14. The auxiliary battery 16 is used as a power source for electrical equipment, similar to the auxiliary battery 12. It also operates on a voltage of 12V to 15V, similar to the auxiliary battery 12, but the auxiliary battery 16 is not a lead-acid battery but a lithium-ion battery (LiB: Lithium-ion Battery). The auxiliary battery 16 supplies power not only to the electrical equipment but also to the second controller 17. The auxiliary battery 12 and the auxiliary battery 16 are sometimes called low-power batteries.

The second controller 17 is an electronic control unit similar to the first controller 13. In this embodiment, the second controller 17 realizes fewer functions compared to the first controller 13. In other words, the amount of software built into the second controller 17 is less than the amount of software built into the first controller 13. As a function common to the second controller 17 and the first controller 13, both controllers have an emergency stop function. However, unlike the first controller 13, the second controller 17 does not have the function of starting the vehicle.

The auxiliary battery 12 and the first controller 13 are arranged upstream from the auxiliary battery 16 and the second controller 17.

A relay 15 is connected between the switching device 14 and the auxiliary battery 16. The on/off of the relay 15 is controlled by any controller. In other words, the ECU that controls the on/off of the relay 15 may be the first controller 13, the second controller 17, or another ECU.

The switching device 14 incorporates an ECU different from the first controller 13 and the second controller 17, and this ECU monitors the voltage of the downstream circuit as viewed from the DCDC converter 11 (hereinafter simply referred to as the circuit voltage). The downstream circuit refers to a circuit arranged in the direction in which power is supplied from the DCDC converter 11. If an abnormality is detected in the downstream circuit voltage, the switching device 14 switches its own open/closed state from on to off to cut off the circuit. This cutoff separates the auxiliary battery 16 and the second controller 17 from the downstream circuit. Note that a case where an abnormality is detected in the downstream circuit voltage refers to, for example, a case where the downstream circuit voltage exceeds a threshold value. This threshold value may be set based on a fail-safe perspective.

Next, the conditions for switching the switching device 14 from off to on will be explained. When the voltages of the auxiliary battery 12 and the auxiliary battery 16 are equal, the switching device 14 turns on. For example, when the vehicle starts, the voltages of the auxiliary battery 12 and the auxiliary battery 16 gradually increase. When the voltages of the auxiliary battery 12 and the auxiliary battery 16 become equal (for example, when the voltages of both batteries become rated voltages), the switching device 14 turns on. Here, "the voltages of the auxiliary battery 12 and the auxiliary battery 16 are equal" does not have to be completely equal. "The voltages of the auxiliary battery 12 and the auxiliary battery 16 are equal" means that they are substantially equal (can be considered to be almost equal).

(Action and Effect)
It is difficult for the auxiliary battery 12 (lead storage battery) to determine by itself whether an abnormality occurs. For this reason, in this embodiment, the auxiliary battery 12 is arranged upstream of the auxiliary battery 16, that is, between the DCDC converter 11 and the switching device 14. By arranging them in this manner, even if an abnormality occurs in the auxiliary battery 12, power is supplied from the DCDC converter 11 to the first controller 13. Therefore, even if an abnormality occurs in the auxiliary battery 12, the stop of the function of the first controller 13 is avoided. For example, as an example, the vehicle is prevented from being unable to start. In this way, according to this embodiment, even if an abnormality occurs in the auxiliary battery 12, the stop of the system function is avoided.

In this embodiment, two auxiliary batteries are used to provide a redundant configuration. Furthermore, different types of batteries (lead-acid batteries and lithium-ion batteries) are used for the two auxiliary batteries. This increases the likelihood of avoiding a situation in which an abnormality occurs in both auxiliary batteries at the same time.

In addition, in this embodiment, two controllers with emergency stop functions are configured to provide a redundant configuration. This ensures reliability in autonomous driving, since even if an abnormality occurs in one of the controllers, the other controller can automatically stop the vehicle.

In addition to the function of starting the vehicle, the first controller 13 also has an emergency stop function (a function of automatically stopping the vehicle). The second controller 17 also has this emergency stop function. The second controller 17 is designed to realize fewer functions than the first controller 13. This reduces the power consumed by the second controller 17, and increases the likelihood that the auxiliary battery 16 will last longer. This is useful in the following cases. Assume that some abnormality occurs in the first controller 13 during automatic driving and an abnormality is detected in the downstream circuit voltage. In this case, the switching device 14 switches from on to off, and the auxiliary battery 16 and the second controller 17 are separated from the downstream circuit. As described above, the second controller 17 has an emergency stop function, and furthermore, the second controller 17 consumes less power. Therefore, even if the auxiliary battery 16 and the second controller 17 are disconnected from the downstream circuit during automatic driving, it is more likely that the auxiliary battery 16 alone will be able to cover the power consumed by the second controller 17, and it is more likely that the vehicle can be stopped automatically.

The switching device 14 also switches its own open/closed state from OFF to ON when the voltages of the auxiliary battery 12 and the auxiliary battery 16 are equal. This makes it possible to prevent the occurrence of inrush current when switching from OFF to ON, and to suppress the magnitude of the inrush current.

As described above, an embodiment of the present invention has been described, but the descriptions and drawings that form part of this disclosure should not be understood as limiting this invention. Various alternative embodiments, examples, and operating techniques will become apparent to those skilled in the art from this disclosure.

Reference Signs List 1 Vehicle control device 10 Driving battery 11 DCDC converter 12, 16 Auxiliary battery 13 First controller 14 Switching device 15 Relay 17 Second controller

Claims (5)

A vehicle control device mounted on a vehicle,
A DC-DC converter that steps down the power of a high-voltage battery;
A switching device connected to the DC-DC converter;
a first auxiliary battery and a first controller connected between the DC-DC converter and the switching device and supplied with power stepped down by the DC-DC converter;
a second auxiliary battery and a second controller connected to the DCDC converter via the switching device,
the first controller has a function of starting the vehicle;
The first controller further has a function of automatically stopping the vehicle,
A vehicle control device characterized in that the second controller has at least a function of automatically stopping the vehicle, while the functions realized by the second controller are fewer than the functions realized by the first controller. 2. The vehicle control device according to claim 1, wherein the first auxiliary battery is a lead-acid battery. 3. The vehicle control device according to claim 1, wherein the second auxiliary battery is a lithium ion battery. The vehicle control device according to any one of claims 1 to 3, characterized in that the first controller has at least one of a function of automatically accelerating and decelerating the vehicle and a function of automatically steering the vehicle. The vehicle control device according to any one of claims 1 to 4, characterized in that the switching device switches its own open/closed state from off to on when the voltages of the first auxiliary battery and the second auxiliary battery are equal.

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