JP7703477B2 - Vehicle control device - Google Patents

Description

This disclosure relates to a vehicle control device.

Devices that perform braking assistance control to control the main brake device and auxiliary brake device to decelerate the vehicle are known. For example, Patent Document 1 describes an autocruise control device that is mounted on a vehicle equipped with a main brake and multiple types of auxiliary brakes, calculates a target deceleration for the vehicle from the distance to the preceding vehicle and the relative speed to the preceding vehicle, compares the target deceleration with multiple thresholds corresponding to the multiple types of auxiliary brakes, and activates the auxiliary brakes in order starting with the brake with the least deceleration according to the target deceleration.

JP 2005-263098 A

The deceleration caused by the activation of the auxiliary brakes on the vehicle depends on the running conditions of the vehicle, such as the speed and weight of the vehicle. Therefore, if the auxiliary brakes to be activated are determined by comparing the target deceleration with multiple thresholds without considering the running conditions of the vehicle, as in the device described in Patent Document 1, a difference may occur between the target deceleration and the actual deceleration. For example, when the vehicle is running at a low speed, activating the auxiliary brake device does not provide the same deceleration as when the vehicle is running at a high speed, and when the vehicle weight has increased due to the loading of cargo, activating the auxiliary brake device does not provide the same deceleration as when no cargo is loaded.

Therefore, this disclosure describes a vehicle control device that can reduce the difference between the target deceleration and the actual deceleration.

In one aspect, a vehicle control device is provided that controls the operation of a main brake and a plurality of auxiliary brake devices that apply a braking force to a vehicle. The vehicle control device includes a vehicle speed acquisition unit that acquires the speed of the vehicle, a target deceleration acquisition unit that acquires a target deceleration of the vehicle, a predicted deceleration calculation unit that calculates a predicted value of the deceleration of the vehicle, and a control unit that controls the operation of the main brake and the plurality of auxiliary brakes based on the predicted value of the deceleration of the vehicle. The multiple auxiliary brake devices are capable of performing a first auxiliary brake operation and a second auxiliary brake operation that applies a braking force to the vehicle that is greater than the first auxiliary brake operation, the predicted deceleration calculation unit calculates a first predicted deceleration that is a predicted value of the deceleration of the vehicle when the first auxiliary brake operation and the second auxiliary brake operation are not performed, and a second predicted deceleration that is a predicted value of the deceleration of the vehicle when the first auxiliary brake operation is performed and the second auxiliary brake operation is not performed, and the control unit controls the multiple auxiliary brake devices so that the first auxiliary brake operation is performed when the vehicle speed is equal to or greater than a first threshold value and the target deceleration is greater than the first predicted deceleration, and the second auxiliary brake operation is performed when the vehicle speed is equal to or greater than a second threshold value that is greater than the first threshold value and the target deceleration is greater than the second predicted deceleration.

The vehicle control device of this embodiment calculates a predicted deceleration value and compares the predicted deceleration value with a target deceleration to control the operation of multiple auxiliary brake devices, thereby making it possible to reduce the difference between the target deceleration and the actual deceleration. In addition, since it is generally difficult to precisely control the braking of auxiliary brake devices like the main brakes, activating the auxiliary brakes when traveling at low speeds can cause a sudden increase in deceleration, which can lead to a deterioration in ride comfort. In this vehicle control device, the auxiliary brake devices are activated when the vehicle speed is above a certain value, making it possible to suppress deterioration in ride comfort.

The vehicle control device of one embodiment further includes a vehicle weight acquisition unit that acquires the weight of the vehicle, and the plurality of auxiliary brake devices are further capable of executing a third auxiliary brake operation that applies a braking force to the vehicle greater than the second auxiliary brake operation, and a fourth auxiliary brake operation that applies a braking force to the vehicle greater than the third auxiliary brake operation, and the predicted deceleration calculation unit calculates a third predicted deceleration that is a predicted value of the deceleration of the vehicle when the first auxiliary brake operation and the second auxiliary brake operation are performed and the third auxiliary brake operation and the fourth auxiliary brake operation are not performed, and a predicted deceleration that is a predicted value of the deceleration of the vehicle when the first auxiliary brake operation and the second auxiliary brake operation are performed and the third auxiliary brake operation and the fourth auxiliary brake operation are not performed. The control unit further calculates a fourth predicted deceleration, which is a predicted value of the deceleration of the vehicle when the brake operation and the third auxiliary brake operation are performed and the fourth auxiliary brake operation is not performed, and controls the multiple auxiliary brake devices so that the third auxiliary brake operation is performed when the vehicle speed is equal to or greater than a third threshold value that is greater than the second threshold value and the target deceleration is greater than the third predicted deceleration, and the fourth auxiliary brake operation is performed when the vehicle speed is equal to or greater than a fourth threshold value that is greater than the second threshold value, the vehicle weight is greater than a fifth threshold value, and the target deceleration is greater than the fourth predicted deceleration. This vehicle control device performs the fourth brake operation when the vehicle weight is equal to or greater than a certain value, thereby suppressing deterioration of ride comfort.

In one embodiment, the predicted deceleration calculation unit further calculates a fifth predicted deceleration, which is a predicted value of the deceleration of the vehicle when the first auxiliary brake operation, the second auxiliary brake operation, the third auxiliary brake operation, and the fourth auxiliary brake operation are performed, and the control unit may operate the main brake when the target deceleration is greater than the fifth predicted deceleration. In this embodiment, the difference between the target deceleration and the deceleration of the vehicle can be reduced while suppressing the use of the main brake.

According to one aspect and various embodiments of the present invention, the difference between the target deceleration and the actual deceleration can be reduced.

1 is a block diagram showing a functional configuration of a vehicle control device according to an embodiment; 4 is a flowchart showing a flow of processing of a vehicle control device. 3 is a flowchart illustrating a continuation of FIG. 2 .

Vehicle control devices according to various embodiments will be described in detail below with reference to the drawings. Note that the same reference numerals will be used to refer to the same or corresponding parts in each drawing, and duplicate descriptions of the same or corresponding parts will be omitted.

Figure 1 is a block diagram showing the functional configuration of a vehicle control device according to one embodiment. The vehicle control device 10 is mounted on a vehicle 1 and executes braking assistance control to decelerate the vehicle. The vehicle 1 on which the vehicle control device 10 is mounted is, for example, a freight vehicle such as a truck or tractor that carries cargo. Note that the vehicle 1 may be a large passenger vehicle such as a bus, or may be an ordinary passenger car, a small vehicle, or a light vehicle.

As shown in FIG. 1, the vehicle 1 is equipped with an external sensor 2, an internal sensor 3, a main brake device 5, multiple auxiliary brake devices 6, and a vehicle control device 10.

The external sensor 2 detects information about the external environment of the vehicle 1. For example, a camera is used as the external sensor 2. The camera captures an image of the area in front of the vehicle 1. The camera may be a monocular camera or a stereo camera. The stereo camera has two imaging units arranged to reproduce binocular parallax. The imaging information of the stereo camera also includes information in the depth direction. The external sensor 2 may include a radar sensor that transmits electromagnetic waves around the vehicle 1 and detects objects by receiving reflected waves from surrounding objects.

The internal sensors 3 collect various information about the vehicle 1. The internal sensors 3 include a vehicle speed sensor and a weight sensor. The vehicle speed sensor detects the speed of the vehicle 1 (hereinafter referred to as "vehicle speed"). As the vehicle speed sensor, for example, a wheel speed sensor that is attached to the wheels or drive shaft of the vehicle and detects the rotational speed of the wheels is used. The weight sensor measures the weight of the vehicle 1 (hereinafter referred to as "vehicle weight"). The vehicle speed sensor and weight sensor output information indicating the measured vehicle speed and vehicle weight to the vehicle control device 10.

The main brake device 5 is a braking device that is responsible for the main braking of the vehicle 1, for example a service brake. The main brake device 5 is provided on each wheel of the vehicle 1, and applies a braking force to the vehicle 1 by applying a frictional force to the wheels according to the amount of operation of the brake pedal.

The plurality of auxiliary braking devices 6 are braking devices that perform auxiliary braking of the vehicle 1. In one embodiment, the plurality of auxiliary braking devices 6 include two or more types of auxiliary braking devices, such as an exhaust brake, a brake pressurizing device, an engine retarder, and a transmission retarder. In the embodiment shown in FIG. 1, the plurality of auxiliary braking devices 6 include an engine retarder 7 and a transmission retarder 8.

The engine retarder 7 is an auxiliary brake device that applies a braking force to the vehicle 1 by forcibly opening the exhaust valve during the engine compression stroke and releasing the engine compression pressure. The braking force applied to the vehicle 1 from the engine retarder 7 can be switched between multiple stages. For example, the operating mode of the engine retarder 7 can be switched between two stages, a weak mode and a strong mode. When the engine retarder 7 operates in the weak mode, a relatively small braking force is applied to the vehicle 1, and when the engine retarder 7 operates in the strong mode, a relatively large braking force is applied to the vehicle 1. In other words, the engine retarder 7 can perform a first auxiliary brake operation and a second auxiliary brake operation that applies a braking force to the vehicle 1 that is larger than the first auxiliary brake operation.

The transmission retarder 8 is a device that applies a frictional force to the output shaft of the transmission of the vehicle 1 to apply a braking force to the vehicle 1. The braking force applied to the vehicle 1 from the transmission retarder 8 can be switched between multiple stages. For example, the operating mode of the transmission retarder 8 can be switched between two stages: a weak mode and a strong mode. When the transmission retarder 8 operates in the weak mode, a relatively small braking force is applied to the vehicle 1, and when the transmission retarder 8 operates in the strong mode, a relatively large braking force is applied to the vehicle 1.

The transmission retarder 8 applies a greater braking force to the vehicle 1 than the engine retarder 7. For example, the braking force of the transmission retarder 8 operating in the weak mode is greater than the braking force of the engine retarder 7 operating in the strong mode. In other words, the transmission retarder 8 can execute a third auxiliary brake operation that applies a greater braking force to the vehicle 1 than the second auxiliary brake operation, and a fourth auxiliary brake operation that applies a greater braking force to the vehicle 1 than the third auxiliary brake operation.

The operation of the engine retarder 7 and the transmission retarder 8 is controlled by the vehicle control device 10. For example, the vehicle control device 10 sends control signals to the engine retarder 7 and the transmission retarder 8 to activate, stop, and switch the operation mode of the engine retarder 7 and the transmission retarder 8.

The vehicle control device 10 is an electronic control unit having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a CAN (Controller Area Network) communication circuit, and the like. The vehicle control device 10 is connected to a network that communicates using, for example, a CAN communication circuit, and is communicatively connected to each component of the vehicle 1. The vehicle control device 10, for example, operates the CAN communication circuit based on a signal output by the CPU to input and output data, stores the data in the RAM, loads a program stored in the ROM into the RAM, and executes the program loaded into the RAM to realize various functions described below. The vehicle control device 10 may be composed of multiple electronic control units. Vehicle control device 10

As shown in FIG. 1, the vehicle control device 10 has, as its functional configuration, a vehicle information acquisition unit 11, a deceleration target detection unit 12, a target deceleration acquisition unit 13, a predicted deceleration calculation unit 14, and a control unit 15.

The vehicle information acquisition unit 11 acquires information about the vehicle 1 (hereinafter referred to as "vehicle information"). For example, the vehicle information acquisition unit 11 acquires the vehicle speed and vehicle weight measured by the internal sensor 3. That is, the vehicle information acquisition unit 11 functions as a vehicle speed acquisition unit that acquires the vehicle speed, and a vehicle weight acquisition unit that acquires the vehicle weight. Furthermore, the vehicle information acquisition unit 11 acquires the engine speed, the transmission gear stage (hereinafter referred to as "gear ratio"), the differential gear gear ratio (hereinafter referred to as "diff ratio"), the total gear ratio (the product of the transmission gear ratio and the differential gear gear ratio), the frontal projection area of the vehicle 1, the road gradient, etc. as vehicle information.

The deceleration target detection unit 12 detects deceleration targets ahead of the vehicle based on the detection results of the external sensor 2. Deceleration targets are targets of deceleration support control. Deceleration targets include curves, traffic lights, stop lines, preceding vehicles, etc. Deceleration support control is control for decelerating the vehicle 1 to a target vehicle speed. The target vehicle speed is set in principle according to the type of target.

The deceleration object detection unit 12 detects the deceleration object by performing pattern matching using pre-stored image patterns for each type of deceleration object, for example, based on an image of the area ahead of the vehicle captured by a camera. For example, if the deceleration object is a stop line, the deceleration object detection unit 12 recognizes the position of the stop line by extracting a white line extending in the width direction of the road using well-known image recognition technology. The deceleration object detection unit 12 may also detect the deceleration object based on the position of an object detected by a radar sensor.

The target deceleration acquisition unit 13 acquires the target deceleration of the vehicle 1. For example, the target deceleration acquisition unit 13 sets the target deceleration based on the speed of the vehicle 1, the distance from the vehicle 1 to the deceleration target, and the target speed. For example, if the deceleration target is a stop line, the target speed before the stop line is 0 km/h. Therefore, the target deceleration acquisition unit 13 sets the target deceleration so that the vehicle 1 can stop before the stop line. Note that deceleration refers to negative acceleration. Therefore, a large deceleration means a small acceleration.

The predicted deceleration calculation unit 14 calculates a predicted value of the deceleration of the vehicle 1 (hereinafter referred to as "predicted deceleration"). For example, the predicted deceleration calculation unit 14 calculates the predicted deceleration based on the deceleration caused by the running resistance of the vehicle 1 and the deceleration caused by the braking forces of the multiple auxiliary brake devices 6. The running resistance of the vehicle 1 includes the air resistance, rolling resistance, gradient resistance, transmission moment of inertia, etc. of the vehicle 1.

The deceleration caused by air resistance is calculated based on, for example, the overall projected area of the vehicle 1, the vehicle speed, and the vehicle weight. The deceleration caused by rolling resistance is calculated based on, for example, the rolling resistance coefficient and the road gradient. The deceleration caused by grade resistance is calculated based on, for example, the road gradient. The transmission moment of inertia is calculated based on, for example, the transmission gear stage, the total gear ratio, the tire radius, and the vehicle weight.

The predicted deceleration calculation unit 14 also predicts the deceleration caused by the braking force of the multiple auxiliary brake devices 6. For example, the storage unit of the vehicle control device 10 stores first deceleration data indicating the relationship between the vehicle speed, the vehicle weight, and the deceleration for each operation mode of the engine retarder 7. The predicted deceleration calculation unit 14 obtains the braking force generated by the operation of the engine retarder 7 by extracting the braking force corresponding to the vehicle speed and the vehicle weight obtained by the vehicle information acquisition unit 11 from the first deceleration data. Note that the predicted deceleration calculation unit 14 may calculate and obtain the deceleration caused by the braking force of the engine retarder 7 based on the engine speed, the differential ratio, the gear ratio, the tire radius of the vehicle 1, and the vehicle weight without using the first deceleration data.

The storage unit of the vehicle control device 10 also stores second deceleration data indicating the relationship between the vehicle speed, vehicle weight, and deceleration for each operation mode of the transmission retarder 8. The predicted deceleration calculation unit 14 obtains the braking force generated by the operation of the transmission retarder 8 by extracting the braking force corresponding to the vehicle speed and vehicle weight acquired by the vehicle information acquisition unit 11 from the second deceleration data. The predicted deceleration calculation unit 14 outputs the sum of the deceleration generated by the running resistance of the vehicle 1 calculated as described above and the deceleration generated by the braking forces of the multiple auxiliary brake devices 6 as the predicted deceleration.

The control unit 15 controls the operation of the main brake device 5 and the multiple auxiliary brake devices 6 based on the target deceleration and the predicted deceleration. For example, the control unit 15 sends control signals to the main brake device 5, the engine retarder 7, and the transmission retarder 8 to control the operation or stop of the main brake device 5, the operation or stop of the engine retarder 7, and the operation or stop of the transmission retarder 8. The control unit 15 also switches the operation mode (weak mode or strong mode) of the engine retarder 7 and the transmission retarder 8.

The functions of the vehicle control device 10 will be described in more detail with reference to Figures 2 and 3. Figures 2 and 3 are flowcharts showing the flow of processing executed by the vehicle control device 10.

As shown in FIG. 2, first, the vehicle information acquisition unit 11 of the vehicle control device 10 acquires vehicle information of the vehicle 1 (step ST1). Specifically, the vehicle information acquisition unit 11 acquires information related to the vehicle speed, vehicle weight, road gradient, total gear ratio, tire radius, engine RPM, and transmission gear stage as vehicle information.

Next, the target deceleration acquisition unit 13 acquires the target deceleration. For example, if a stop line is present ahead of the vehicle 1, the target deceleration acquisition unit 13 sets a target deceleration that allows the vehicle 1 to stop just before the stop line.

Next, the predicted deceleration calculation unit 14 calculates a first predicted deceleration, which is a predicted value of the deceleration when the operation of the main brake device 5 and the multiple auxiliary brake devices 6 is stopped (step ST3). In other words, the first predicted deceleration is a predicted value of the deceleration of the vehicle 1 when the first auxiliary brake operation and the second auxiliary brake operation are not performed. For example, the predicted deceleration calculation unit 14 calculates the sum of the deceleration caused by the running resistance (air resistance, rolling resistance, and gradient resistance) of the vehicle 1 and the deceleration caused by the engine brake of the vehicle 1 as the first predicted deceleration.

Next, the control unit 15 determines whether or not a first operating condition, which is a condition for operating the engine retarder 7 in the weak mode, is satisfied (step ST4). For example, the control unit 15 determines that the first operating condition is satisfied when the vehicle speed is equal to or greater than a first speed (first threshold value) and the target deceleration is greater than a first predicted deceleration. The first speed is a preset speed, for example, 8 km/h.

When the first operating condition is met, the control unit 15 controls the engine retarder 7 to operate the engine retarder 7 in the weak mode (step ST5). As described above, the engine retarder 7 is operated in the weak mode when the vehicle speed is equal to or higher than the first speed and it is predicted that the deceleration when the operation of the engine retarder 7 and the transmission retarder 8 is stopped will not reach the target deceleration.

Next, the predicted deceleration calculation unit 14 calculates a second predicted deceleration, which is a predicted value of the deceleration when the engine retarder 7 is operated in the weak mode and the operation of the main brake device 5 and the transmission retarder 8 is stopped (step ST6). For example, the predicted deceleration calculation unit 14 calculates the second predicted deceleration as the sum of the deceleration caused by the running resistance of the vehicle 1, the deceleration caused by the engine brake of the vehicle 1, and the deceleration caused by the engine retarder 7 operating in the weak mode. At this time, the predicted deceleration calculation unit 14 obtains the deceleration caused by the engine retarder 7 operating in the weak mode by extracting the deceleration corresponding to the vehicle speed and vehicle weight acquired by the vehicle information acquisition unit 11 from the first deceleration data.

Next, the control unit 15 determines whether or not a second operating condition, which is a condition for operating the engine retarder 7 in the strong mode, is satisfied (step ST7). For example, the control unit 15 determines that the second operating condition is satisfied when the vehicle speed is the second speed (second threshold value) and the target deceleration is greater than the second predicted deceleration. The second speed is a speed higher than the first speed, for example, 10 km/h.

When the second operating condition is met, the control unit 15 controls the engine retarder 7 to operate the engine retarder 7 in the strong mode (step ST8). As described above, the engine retarder 7 is operated in the strong mode when the vehicle speed is equal to or higher than the first speed and it is predicted that the deceleration when the engine retarder 7 is operated in the weak mode will not reach the target deceleration.

Next, the predicted deceleration calculation unit 14 calculates a third predicted deceleration, which is a predicted value of the deceleration when the engine retarder 7 is operated in the strong mode and the operation of the main brake device 5 and the transmission retarder 8 is stopped (step ST9). For example, the predicted deceleration calculation unit 14 calculates the third predicted deceleration as the sum of the deceleration caused by the running resistance of the vehicle 1, the deceleration caused by the engine brake, and the deceleration caused by the engine retarder 7 operating in the strong mode.

Next, as shown in FIG. 3, the control unit 15 determines whether a third operating condition, which is a condition for operating the transmission retarder 8 in the weak mode, is met (step ST10). For example, the control unit 15 determines that the third operating condition is met when the vehicle speed is equal to or greater than a third speed (third threshold value) and the target deceleration is greater than a third predicted deceleration. The third speed is a speed higher than the second speed, for example, 20 km/h.

When the third operating condition is met, the control unit 15 controls the transmission retarder 8 to operate the transmission retarder 8 in weak mode (step ST11). As described above, when the vehicle speed is equal to or higher than the third speed and it is predicted that the deceleration when the engine retarder 7 is operated in strong mode will not reach the target deceleration, the engine retarder 7 is operated in strong mode and the transmission retarder 8 is operated in weak mode.

Next, the predicted deceleration calculation unit 14 calculates a fourth predicted deceleration, which is a predicted value of the deceleration when the operation of the main brake device 5 is stopped, the engine retarder 7 is operated in the strong mode, and the transmission retarder 8 is operated in the weak mode (step ST12). For example, the predicted deceleration calculation unit 14 calculates the fourth predicted deceleration as the sum of the deceleration caused by the running resistance of the vehicle 1, the deceleration caused by the engine brake, the deceleration caused by the engine retarder 7 operating in the strong mode, and the deceleration caused by the transmission retarder 8 operating in the weak mode. At this time, the predicted deceleration calculation unit 14 obtains the deceleration caused by the transmission retarder 8 operating in the weak mode by extracting the deceleration corresponding to the vehicle speed and vehicle weight acquired by the vehicle information acquisition unit 11 from the second deceleration data, for example.

Next, the control unit 15 determines whether or not a fourth operating condition, which is a condition for operating the transmission retarder 8 in the strong mode, is met (step ST13). For example, the control unit 15 determines that the fourth operating condition is met when the vehicle speed is equal to or greater than a fourth speed (fourth threshold), the vehicle weight is equal to or greater than a predetermined weight (fifth threshold), and the target deceleration is greater than a fourth predicted deceleration. The fourth speed is a speed higher than the second speed, for example 20 km/h. The predetermined weight is a preset weight, for example 10 t.

When the fourth operating condition is met, the control unit 15 controls the transmission retarder 8 to operate the transmission retarder 8 in the strong mode (step ST14). As described above, when the vehicle speed is equal to or higher than the fourth speed, the vehicle speed is equal to or higher than a predetermined weight, and it is predicted that the deceleration when the transmission retarder 8 is operated in the weak mode will not reach the target deceleration, the engine retarder 7 is operated in the strong mode and the transmission retarder 8 is operated in the strong mode.

Next, the predicted deceleration calculation unit 14 calculates a fifth predicted deceleration, which is a predicted value of the deceleration when the operation of the main brake device 5 is stopped and the engine retarder 7 and the transmission retarder 8 are operated in the strong mode (step ST15). For example, the predicted deceleration calculation unit 14 calculates the fifth predicted deceleration as the sum of the deceleration caused by the running resistance of the vehicle 1, the deceleration caused by the engine brake, the deceleration caused by the engine retarder 7 operating in the strong mode, and the deceleration caused by the transmission retarder 8 operating in the strong mode.

Next, the control unit 15 determines whether a fifth operating condition, which is a condition for operating the main brake device 5, is satisfied (step ST16). For example, the control unit 15 determines that the fifth operating condition is satisfied when the target deceleration is greater than the fifth predicted deceleration.

When the fifth operating condition is satisfied, the control unit 15 operates the main brake device 5 (step ST17). At this time, the control unit 15 controls the main brake device 5 so that a deceleration that is insufficient is generated according to the difference between the target deceleration and the fifth predicted deceleration. As described above, the main brake device 5 is operated when it is predicted that the deceleration when the engine retarder 7 and the transmission retarder 8 are operated in the strong mode will not reach the target deceleration, so that excessive use of the main brake device 5 is suppressed and the life of the main brake device 5 is extended.

Furthermore, if it is determined in steps ST4, ST7, ST10, and ST13 that the first to fourth operating conditions are not satisfied, the control unit 15 determines whether or not a sixth operating condition, which is a condition for operating the main brake device 5, is satisfied (step ST18). For example, the control unit 15 determines that the sixth operating condition is satisfied when the vehicle speed is equal to or higher than the fifth speed and the target deceleration is equal to or higher than a predetermined deceleration. The fifth speed is a speed lower than the first speed, for example, 2 km/h. The predetermined deceleration is, for example, −0.05 mm/s ^2. In one embodiment, the control unit 15 may determine that the sixth operating condition is satisfied when the vehicle speed is equal to or higher than the second speed and the target deceleration is greater than the deceleration caused by the running resistance of the vehicle 1.

If the sixth activation condition is met, the control unit 15 activates the main brake device 5 (step ST19).

The vehicle control device 10 described above calculates a predicted deceleration value, compares the predicted deceleration value with a target deceleration, and controls the operation of multiple auxiliary brake devices, so that the difference between the target deceleration and the actual deceleration can be reduced. Furthermore, unlike the main brakes, precise braking control is difficult for the engine retarder 7 and the transmission retarder 8. Therefore, for example, if the engine retarder 7 and the transmission retarder 8 are operated when the vehicle speed is low, the vehicle 1 may suddenly decelerate, which may deteriorate the ride comfort of the occupants. In contrast, the vehicle control device 10 operates the engine retarder 7 and the transmission retarder 8 when the vehicle speed is equal to or higher than a certain value, so that deterioration of the ride comfort can be suppressed.

Although the vehicle control device according to various embodiments has been described above, the present invention is not limited to the above-mentioned embodiments, and various modifications can be made without changing the gist of the invention. In other words, it should be noted that the above-mentioned embodiments are intended as illustrative examples and do not limit the scope of the present invention. The above-mentioned various embodiments can be combined to the extent that no contradictions are present.

1...vehicle, 5...main brake device, 6...auxiliary brake device, 10...vehicle control device, 13...target deceleration acquisition unit, 14...predicted deceleration calculation unit, 15...control unit.

Claims (3)

A vehicle control device that controls operation of a main brake and a plurality of auxiliary brake devices that apply a braking force to a vehicle,
A vehicle speed acquisition unit that acquires a speed of the vehicle;
a target deceleration acquisition unit that acquires a target deceleration of the vehicle;
a predicted deceleration calculation unit that calculates a predicted value of deceleration of the vehicle;
a control unit that controls operation of the main brake and the plurality of auxiliary brakes based on a predicted value of deceleration of the vehicle;
Equipped with
the plurality of auxiliary brake devices are capable of performing a first auxiliary brake operation and a second auxiliary brake operation that applies a braking force to the vehicle that is greater than the first auxiliary brake operation;
the predicted deceleration calculation unit calculates a first predicted deceleration which is a predicted value of deceleration of the vehicle when the first auxiliary brake operation and the second auxiliary brake operation are not performed, and a second predicted deceleration which is a predicted value of deceleration of the vehicle when the first auxiliary brake operation is performed and the second auxiliary brake operation is not performed;
The control unit controls the plurality of auxiliary brake devices so that the first auxiliary brake operation is performed when the speed of the vehicle is equal to or greater than a first threshold value and the target deceleration is greater than the first predicted deceleration, and the second auxiliary brake operation is performed when the speed of the vehicle is equal to or greater than a second threshold value that is greater than the first threshold value and the target deceleration is greater than the second predicted deceleration.
Vehicle control device. A vehicle weight acquisition unit that acquires a weight of the vehicle is further provided.
the plurality of auxiliary brake devices are further capable of executing a third auxiliary brake operation that applies a braking force greater than the second auxiliary brake operation to the vehicle, and a fourth auxiliary brake operation that applies a braking force greater than the third auxiliary brake operation to the vehicle,
the predicted deceleration calculation unit further calculates a third predicted deceleration which is a predicted value of deceleration of the vehicle when the first auxiliary brake operation and the second auxiliary brake operation are performed and the third auxiliary brake operation and the fourth auxiliary brake operation are not performed, and a fourth predicted deceleration which is a predicted value of deceleration of the vehicle when the first auxiliary brake operation, the second auxiliary brake operation, and the third auxiliary brake operation are performed and the fourth auxiliary brake operation is not performed,
2. The vehicle control device according to claim 1, wherein the control unit controls the plurality of auxiliary brake devices so that the third auxiliary brake operation is performed when the speed of the vehicle is equal to or greater than a third threshold greater than the second threshold and the target deceleration is greater than the third predicted deceleration, and the fourth auxiliary brake operation is performed when the speed of the vehicle is equal to or greater than a fourth threshold greater than the second threshold, the weight of the vehicle is greater than a fifth threshold, and the target deceleration is greater than the fourth predicted deceleration. the predicted deceleration calculation unit further calculates a fifth predicted deceleration which is a predicted value of a deceleration of the vehicle when the first auxiliary brake operation, the second auxiliary brake operation, the third auxiliary brake operation, and the fourth auxiliary brake operation are performed;
The vehicle control device according to claim 2 , wherein the control unit activates the main brake when the target deceleration is greater than the fifth predicted deceleration.

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