Vehicle control device

Abstract

To enable a vehicle control device to generate regenerative torque suitable to vehicle speed when executing vehicle speed limit.SOLUTION: A vehicle control device (100) is a vehicle control device which controls a vehicle (1) installing an internal combustion engine (2) and a motor generator (3) and is provided with regenerative brake control means (101) which generates regenerative torque by the motor generator (3) when prescribed condition is satisfied when a brake is not operated. The regenerative brake control means (101) determines the regenerative torque when executing vehicle speed limit which limits vehicle speed when the vehicle speed is prescribed vehicle speed or more by acceleration operation of an operator, that's to say, the prescribed condition satisfaction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a vehicle control device that controls a vehicle equipped with an internal combustion engine and a motor generator. [Background technology]

[0002] As a technique relating to regenerative brake control, Patent Document 1 discloses a technique for generating coasting regenerative torque by a motor generator during coasting. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-177084 A Summary of the Invention [Problem to be solved by the invention]

[0004] As described in Patent Document 1, it is known that regenerative torque is generated when the vehicle is coasting, when the driver is not operating the brakes. In addition, it is also useful to generate regenerative torque when the vehicle speed is limited by a speed limiter function. Here, the generation of regenerative torque during coasting reflects the driver's intention to decelerate, and in order to increase power generation efficiency, it is desirable to make the regenerative torque as large as possible. However, if regenerative torque is generated when the vehicle speed is limited, just as when coasting, the speed limiter function will be repeatedly turned on and off, which may cause the driver to feel uncomfortable.

[0005] The present invention has been made in consideration of the above circumstances, and has an object to make it possible to generate a regenerative torque appropriate for a vehicle speed limit when the vehicle speed limit is implemented. [Means for solving the problem]

[0006] The vehicle control device of the present invention is a vehicle control device that controls a vehicle equipped with an internal combustion engine and a motor generator, and is equipped with a regenerative brake control means that generates regenerative torque in the motor generator when a predetermined condition is met when the brakes are not operated, and is characterized in that the regenerative brake control means determines the regenerative torque when implementing vehicle speed limiting, which limits the vehicle speed when the vehicle speed becomes equal to or exceeds a predetermined vehicle speed due to the driver's acceleration operation, when the predetermined condition is met. Effect of the Invention

[0007] According to the present invention, when a vehicle speed limit is implemented, it is possible to generate a regenerative torque appropriate for the limit. [Brief description of the drawings]

[0008] [Figure 1] 1 is a diagram showing a schematic configuration of a main part of an automobile according to an embodiment of the present invention; [Diagram 2] 11A and 11B are diagrams illustrating an example of regenerative torque when a vehicle speed limit is implemented and an example of regenerative torque when coasting. [Diagram 3] 4 is a characteristic diagram showing time-series changes in vehicle speed, actual engine torque, and motor torque. FIG. [Figure 4] 11A and 11B are diagrams illustrating an example of regenerative torque when a vehicle speed limit is implemented and an example of regenerative torque when coasting. [Diagram 5] 11A and 11B are diagrams illustrating an example of regenerative torque when a vehicle speed limit is implemented and an example of regenerative torque when coasting. [Figure 6] 11A and 11B are diagrams illustrating an example of regenerative torque when a vehicle speed limit is implemented and an example of regenerative torque when coasting. [Figure 7] 11A and 11B are diagrams illustrating an example of regenerative torque when a vehicle speed limit is implemented and an example of regenerative torque when coasting. [Figure 8] 4 is a characteristic diagram showing time-series changes in vehicle speed, actual engine torque, and motor torque. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] A vehicle control device (100) according to one embodiment of the present invention is a vehicle control device that controls a vehicle (1) equipped with an internal combustion engine (2) and a motor generator (4), and includes a regenerative brake control means (101) that generates regenerative torque in the motor generator (4) when a predetermined condition is satisfied when the brakes are not being operated, and the regenerative brake control means (101) determines the regenerative torque to be used when implementing a vehicle speed limit that limits the vehicle speed when the vehicle speed becomes equal to or exceeds a predetermined vehicle speed due to the driver's acceleration operation, which is the satisfaction of the predetermined condition. This makes it possible to generate a regenerative torque appropriate for the vehicle speed limit. EXAMPLES

[0010] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 shows a schematic configuration of a main part of an automobile 1 which is a vehicle according to the embodiment. As shown in FIG. 1, an automobile 1 is equipped with an engine 2 and a motor generator 3.

[0011] The engine 2 is an internal combustion engine having multiple cylinders, and is configured to perform a series of four strokes, consisting of an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke, for each cylinder, to output power. The power output by the engine 2 is changed in speed by a transmission 5 and is used to drive the automobile 1.

[0012] The motor generator 3 is connected to the engine 2 via a belt 4 or the like. The motor generator 3 functions as an electric motor that rotates the output shaft of the engine 2 by being driven by electric power supplied from a battery 6. The motor generator 3 also functions as a generator that generates electric power to charge the battery 6 by being driven by the output shaft of the engine 2.

[0013] The automobile 1 is also equipped with an ECU (Electronic Control Unit) 100 that electronically controls various functions of the automobile 1. The ECU 100 is connected to various sensors (e.g., a vehicle speed sensor 8, etc.). The ECU 100 is responsible for engine control, and performs fuel supply control by an injector 7 and ignition timing control. The automobile 1 also has a speed limiter function, and the ECU 100 implements a vehicle speed limit that limits the vehicle speed when the vehicle speed exceeds a predetermined speed due to an acceleration operation by the driver. The ECU 100 thus configured is composed of a computer unit that includes, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory that stores backup data, etc., an input port, and an output port.

[0014] In this embodiment, the ECU 100 functions as a vehicle control device to which the present invention is applied. The following mainly describes the function of the vehicle control device to which the present invention is applied. The ECU 100 includes a regenerative brake control unit 101 that generates a regenerative torque in the motor generator 3 when a predetermined condition is satisfied while the brake is not being operated. The predetermined condition is satisfied when the vehicle is coasting or when the vehicle speed is limited by a speed limiter function.

[0015] Coasting is a state in which the vehicle coasts without a driving force request from the driver, i.e., with the accelerator off (the accelerator pedal depression is within a predetermined range close to zero). Generating regenerative torque while coasting reflects the driver's intention to decelerate, and allows the vehicle to decelerate to a level satisfactory to the driver. Therefore, in order to increase power generation efficiency, it is desirable to make the regenerative torque as large as possible.

[0016] However, if regenerative torque is generated in the same way as when coasting when the vehicle speed is limited, the speed limiter function will be repeatedly turned on and off, as described below, which may cause the driver to feel uncomfortable. Here, referring to Fig. 8, a situation will be described in which the speed limiter function is repeatedly turned on and off by generating regenerative torque when the vehicle speed is limited. Fig. 8 is a characteristic diagram showing time-series changes in vehicle speed, actual torque of engine 2, and motor torque. Motor torque is the torque of motor generator 3, and regenerative torque is expressed as a negative value. In Fig. 8, the regenerative torque when the vehicle speed is limited is set to the same as the regenerative torque when coasting at the same vehicle speed.

[0017] As shown in FIG. 8, as a result of an increase in vehicle speed due to an acceleration operation by the driver, at timing t1, the vehicle speed exceeds a predetermined vehicle speed (vehicle speed limit), and the vehicle speed is limited by the speed limiter function. The vehicle speed limit is implemented, for example, by reducing the amount of fuel supplied by the injector 7 and limiting the maximum value of the engine torque. From timing t1 to t2, the actual torque of the engine 2 is limited to the lower limit combustion torque, but is greater than the loss torque, so that the actual torque remains positive and the vehicle speed continues to increase, although the slope becomes gentle. The loss torque corresponds to friction resistance, air resistance, power generation resistance, mechanical loss, etc. At timing t2, in order to suppress an increase in vehicle speed, fuel injection from the injector 7 is cut off and regenerative torque is generated. Timing t2 is, for example, the timing when the vehicle speed reaches a predetermined threshold value (vehicle speed limit + α (α is a predetermined positive value)). Due to this regenerative torque, the vehicle speed starts to decrease. In the state in which fuel injection is cut off and regenerative torque is generated (timings t2 to t4), the actual torque of the engine 2 is the sum of the loss torque and the regenerative torque. As a result of the decrease in vehicle speed, at timing t3 the vehicle speed falls below the speed limit, and between timings t3 and t4 preparations are made for the resumption of fuel injection and the release of regenerative torque. Then, at timing t4, fuel injection is resumed and the regenerative torque is released, and the speed limiter function is turned off. After passing timing t4, the vehicle speed increases again, and at timing t5, the vehicle speed exceeds the vehicle speed limit, and the speed limiter function implements the vehicle speed limit. Thereafter, from timing t6 to t8, the same behavior as that at timings t2 to t4 occurs. After that, the vehicle speed increases again after passing timing t8, and at timing t9, the vehicle speed exceeds the vehicle speed limit, and the speed limiter function implements the vehicle speed limit, and although not shown, the same behavior as that at timings t2 to t4 occurs. Thereafter, the same continues. In this way, the speed limiter function is repeatedly turned on and off, which may cause the driver to feel uncomfortable.

[0018] In this way, rather than generating regenerative torque when the vehicle speed limit is implemented in the same way as when coasting, it is preferable that the regenerative torque when the vehicle speed limit is implemented and the regenerative torque when coasting are determined according to their respective characteristics. As shown in FIG. 1, the regenerative brake control unit 101 includes a regenerative torque determination unit 101a that determines the regenerative torque when the vehicle speed limit is implemented and the regenerative torque when coasting. FIG. 2 shows an example of the regenerative torque when the vehicle speed limit is implemented and the regenerative torque when coasting. In this example, the regenerative torque when the vehicle speed limit is implemented is set as a constant value regardless of the vehicle speed and is set to be smaller than the regenerative torque when coasting at the same vehicle speed. The regenerative torque determination unit 101a determines the regenerative torque when the vehicle speed limit is implemented and the regenerative torque when coasting based on the characteristic curve shown in FIG. 2.

[0019] Fig. 3 is a characteristic diagram showing time series changes in vehicle speed, actual torque of the engine 2, and motor torque. In Fig. 3, as shown in Fig. 2, the regenerative torque when the vehicle speed is limited is determined to be smaller than the regenerative torque when coasting at the same vehicle speed. The timings t1 and t2 are as described in FIG. 8. At the timing t1, the vehicle speed exceeds the vehicle speed limit, the vehicle speed limit is implemented by the speed limiter function, and at the timing t2, the fuel injection is cut off and the regenerative torque is generated. Here, the dotted lines 304-306 are the same characteristic lines as those described in FIG. 8, and at the timing t3, the vehicle speed falls below the vehicle speed limit. On the other hand, as shown by the solid lines 301-303, by making the regenerative torque when the vehicle speed limit is implemented smaller than the regenerative torque when coasting at the same vehicle speed, in other words, by making it smaller than the regenerative torque in the example of FIG. 8, the vehicle speed falls below the vehicle speed limit at the timing t3' after the timing t3. In this way, when the regenerative torque is generated when the vehicle speed limit is implemented, it is possible to prevent the vehicle speed from falling below the vehicle speed limit. This makes it possible to prevent the speed limiter function from being repeatedly turned on and off, thereby reducing the discomfort of the driver.

[0020] As described above, the regenerative torque when the vehicle speed is limited is determined according to the characteristics, and the regenerative torque when the vehicle speed is limited is determined to be smaller than the regenerative torque when the vehicle coasts at the same vehicle speed. This makes it possible to prevent the vehicle speed from falling below the vehicle speed limit when generating regenerative torque when the vehicle speed is limited. This makes it possible to prevent the speed limiter function from repeatedly turning on and off, thereby reducing the sense of discomfort felt by the driver. In this way, it becomes possible to generate a regenerative torque appropriate for the vehicle speed limit when the vehicle speed is limited.

[0021] Hereinafter, the modified example will be described with reference to Fig. 4 to Fig. 7. Fig. 4 to Fig. 7 show examples of the regenerative torque when the vehicle speed is limited and when the vehicle is coasting. In the example of Fig. 2, the regenerative torque when the vehicle speed limit is implemented is not dependent on the accelerator operation amount. In contrast, in the example shown in Fig. 4, the regenerative torque when the vehicle speed limit is implemented is determined according to the accelerator operation amount. As shown in Fig. 4, the regenerative torque when the accelerator opening is small and when it is large are both constant values ​​regardless of the vehicle speed, but the regenerative torque when the accelerator opening is small is made larger than the regenerative torque when the accelerator opening is large. When the accelerator opening is small, specifically when the accelerator pedal is only slightly depressed, there is a possibility that the accelerator pedal will be released and the vehicle will decelerate. When the accelerator pedal is only slightly depressed, the vehicle speed is less likely to exceed the speed limit again and the speed limiter function is less likely to repeatedly turn on and off, so the regenerative torque is made larger to increase power generation efficiency.

[0022] In addition, in the example of Fig. 2, the regenerative torque when the vehicle speed limit is implemented is a constant value regardless of the vehicle speed. In contrast, in the examples shown in Fig. 5 to Fig. 7, the regenerative torque when the vehicle speed limit is implemented is determined according to the vehicle speed in a range equal to or higher than the vehicle speed limit. As shown in Fig. 5, in a vehicle speed range above the speed limit, the regenerative torque when the vehicle speed limit is implemented is increased as the vehicle speed increases. When the vehicle speed is high, the vehicle speed is decreased and the regenerative torque is increased, so the vehicle speed does not immediately fall below the speed limit, reducing the driver's discomfort and improving power generation efficiency. Also, compared to the example shown in Fig. 6 described next, power generation efficiency can be improved when the vehicle speed approaches the speed limit. Alternatively, as shown in Fig. 6, in a vehicle speed range above the limit vehicle speed, the regenerative torque is set to a constant value regardless of vehicle speed up to a threshold value V1 in the vehicle speed range, but as the vehicle speed increases within the range above threshold value V1, the regenerative torque when the vehicle speed limit is implemented is increased. In this case, as in the example shown in Fig. 5, it is possible to improve power generation efficiency while reducing discomfort felt by the driver. Also, compared to the example shown in Fig. 5, it is possible to reliably suppress repeated on / off of the speed limiter function when the vehicle speed approaches the limit vehicle speed. Alternatively, as shown in Fig. 7, in a vehicle speed range above the vehicle speed limit and below a threshold V2 in that vehicle speed range, the regenerative torque when the vehicle speed limit is implemented is increased as the vehicle speed increases, and is set to a constant value regardless of the vehicle speed in a range above the threshold V2. In this case, as in the example shown in Fig. 5, it is possible to increase the power generation efficiency while reducing the driver's sense of discomfort. Also, compared to the example shown in Fig. 5, it is possible to suppress the feeling of deceleration from becoming too strong in the high-speed range.

[0023] The specific process performed by the regenerative torque determination unit 101a to determine the regenerative torque is not limited. A map showing the characteristic lines as shown in Fig. 2 and Fig. 4 to Fig. 7 or a table showing the value of the regenerative torque according to the characteristic line may be stored, and the regenerative torque determination unit 101a may read out the value of the regenerative torque. Alternatively, a calculation formula for the regenerative torque according to the characteristic line may be stored, and the regenerative torque determination unit 101a may calculate the value of the regenerative torque.

[0024] Although the embodiments of the present invention have been described in detail above with reference to the drawings, each embodiment merely shows a specific example of the implementation of the present invention. The technical scope of the present invention is not limited to each embodiment. Various modifications of the present invention are possible without departing from the spirit of the present invention, and these modifications are also included in the technical scope of the present invention. A vehicle control device to which the present invention is applied is configured by a computer device equipped with, for example, a CPU, ROM, RAM, etc., and the functions of each means are realized by the CPU executing a predetermined program stored, for example, in the ROM. [Explanation of symbols]

[0025] 1: automobile, 2: engine, 3: motor generator, 100: ECU, 101: regenerative brake control unit, 101a: regenerative torque determination unit

Claims

1. A vehicle control device for controlling a vehicle equipped with an internal combustion engine and a motor generator, a regenerative brake control means for causing the motor generator to generate a regenerative torque when a predetermined condition is satisfied while the brake is not being operated, A vehicle control device characterized in that the regenerative brake control means determines the regenerative torque when implementing vehicle speed limiting, which limits the vehicle speed when the vehicle speed becomes equal to or exceeds a predetermined vehicle speed due to the driver's acceleration operation, when the predetermined condition is satisfied.

2. The satisfaction of the predetermined condition includes implementation of the vehicle speed limit and satisfaction of a condition other than the implementation of the vehicle speed limit, 2. The vehicle control device according to claim 1, wherein the regenerative brake control means reduces the regenerative torque when the vehicle speed limit is implemented, compared to the regenerative torque when the different condition is satisfied at the same vehicle speed.

3. 3. The vehicle control device according to claim 2, wherein the satisfaction of the other condition is coasting.

4. 3. The vehicle control device according to claim 1, wherein the regenerative brake control means determines a regenerative torque when the vehicle speed limit is implemented in accordance with an accelerator depression amount.

5. 3. The vehicle control device according to claim 1, wherein the regenerative brake control means determines a regenerative torque when the vehicle speed limit is to be implemented, in accordance with a vehicle speed in a range equal to or higher than the predetermined vehicle speed.

6. 6. The vehicle control device according to claim 5, wherein the regenerative brake control means increases the regenerative torque when implementing the vehicle speed limit as the vehicle speed increases in a vehicle speed range equal to or higher than the predetermined vehicle speed.

7. The vehicle control device according to claim 5, characterized in that the regenerative brake control means increases the regenerative torque when implementing the vehicle speed limit as the vehicle speed increases in a range of vehicle speeds equal to or greater than the specified vehicle speed and equal to or greater than a threshold value in the vehicle speed range.

8. The vehicle control device according to claim 5, characterized in that the regenerative brake control means increases the regenerative torque when implementing the vehicle speed limit as the vehicle speed increases within a range above the specified vehicle speed and below a threshold value in the vehicle speed range.

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