Control device for hybrid vehicle

Abstract

To prevent an excessive load from being imposed on a motor and to increase responsiveness of an engine in response to an operation made by a driver.SOLUTION: A first MG 71, a second MG 72, and an engine 10 are coupled to one another via a planetary gear mechanism. A memory 102 stores, as target information, a predicted rotational speed of a ring gear when a vehicle 500 travels at a specific travel position in a double operational state in which both of an accelerator operation and a brake operation by a driver are being performed, a maximum rotational speed which is a maximum value of a rotational speed that can be achieved by the first MG 71, and a dedicated rotational speed which is a rotational speed taken by a carrier when a sun gear is at the maximum rotational speed and when the ring gear is at the predicted rotational speed on a collinear diagram. A CPU 101 controls the first MG 71, the second MG 72, and the engine 10 based on the target information when the vehicle 500 travels in a certain region including the specific travel position in the double operational state.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] This invention relates to a control device for a hybrid vehicle.

Background Art

[0002] The vehicle disclosed in Patent Document 1 includes a first motor, a second motor, an engine, and a planetary gear mechanism. The first motor, the second motor, and the engine are connected to each other via the planetary gear mechanism. The first motor, the second motor, and the engine operate in conjunction with each of the three rotating elements in the planetary gear mechanism. Further, the above vehicle employs a so-called brake override system (hereinafter referred to as BOS). BOS gives priority to the braking of the vehicle based on the depression of the brake pedal over the acceleration of the vehicle based on the depression of the accelerator pedal when both the accelerator pedal and the brake pedal are depressed simultaneously.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] A vehicle such as that in Patent Document 1, which connects two motors and an engine via a planetary gear mechanism, may be used in a circuit race. Here, if BOS is used in a race, there is a possibility that the response of the vehicle to each pedal operation by the driver before and after a curve may be delayed. Further, in a race, unlike when driving on a normal road, the driving involves rapid acceleration and deceleration, so the motors and the engine are likely to be burdened. There is a need for a technology that can achieve a prompt response to the driver's operation while taking such a burden into consideration.

Means for Solving the Problems

[0005] A control device for a hybrid vehicle for solving the above problems is applied to a hybrid vehicle including a ring gear interlocked with drive wheels, a sun gear rotating about the center of the ring gear, a pinion gear interposed between the sun gear and the ring gear and revolving around the sun gear, and a carrier rotating as the pinion gear revolves, an engine having an output shaft connected to the carrier, a first motor interlocked with the sun gear, a second motor interlocked with the ring gear, and a camera for imaging the surroundings. The control device includes an execution unit and a storage unit. The storage unit stores in advance, as target information, a predicted rotational speed of the ring gear when the hybrid vehicle travels at a specific traveling position in a both-operations state where both an accelerator operation and a brake operation by a driver are being performed, a maximum rotational speed which is the maximum value of the rotational speed that the first motor can achieve, and a designated rotational speed which is the rotational speed taken by the carrier when the sun gear is at the maximum rotational speed and the ring gear is at the predicted rotational speed on a collinearity diagram showing the relationship between the rotational speeds of the sun gear, the carrier, and the ring gear. The execution unit performs a first process of acquiring the traveling position of the hybrid vehicle based on an imaged image of the camera during traveling of the hybrid vehicle, and a second process including a process of acquiring the target information when the hybrid vehicle travels in a certain area including the specific traveling position in the both-operations state, and a process of controlling the first motor, the second motor, and the engine based on the acquired target information.

Advantages of the Invention

[0006] In the above technical idea, an excessive load on the first motor is prevented, and the responsiveness of the engine to the driver's operation is increased.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Embodiment for Carrying Out the Invention

[0008] <Overall Configuration of Vehicle> Hereinafter, an embodiment of a control device for a hybrid vehicle will be described with reference to the drawings. As shown in FIG. 1, a hybrid vehicle (hereinafter referred to as a vehicle) 500 includes an engine 10, a power split integrated mechanism 40 to which a crankshaft 14, which is an output shaft of the engine 10, is connected, and a first motor generator (hereinafter referred to as the first MG) 71 and a second motor generator (hereinafter referred to as the second MG) 72 that are connected to the power split integrated mechanism 40.

[0009] The power split integrated mechanism 40 is a planetary gear mechanism and includes a sun gear 41 of an external gear and a ring gear 42 of an internal gear. The sun gear 41 is located at the center of the ring gear 42. The sun gear 41 rotates coaxially with the ring gear 42. A plurality of pinion gears 43 are interposed between the sun gear 41 and the ring gear 42. Each pinion gear 43 meshes with both the sun gear 41 and the ring gear 42. Each pinion gear 43 is supported by a carrier 44 in a state where it can rotate and revolve around the sun gear 41. The carrier 44 rotates coaxially with the sun gear 41 as the pinion gear 43 revolves.

[0010] The sun gear 41 is connected to the first MG 71. That is, the sun gear 41 is configured to interlock with the first MG 71. The carrier 44 is connected to the crankshaft 14. That is, the carrier 44 is configured to interlock with the crankshaft 14. The ring gear 42 is connected to the ring gear shaft 45. And the ring gear shaft 45 is connected to the second MG 72 via the reduction gear 50. That is, the ring gear shaft 45 and thus the ring gear 42 are configured to interlock with the second MG 72. Further, the ring gear shaft 45 is connected to the left and right drive wheels 62 via the speed reduction mechanism 60 and the differential 61. That is, the ring gear shaft 45 and thus the ring gear 42 are configured to interlock with the drive wheels 62. Note that the first MG 71 and the second MG 72 individually exchange electric power with the battery 77 via the inverters 90 and 91.

[0011] The reduction gear 50 is a planetary gear mechanism. That is, the reduction gear 50 includes an internal gear ring gear 52, an external gear sun gear 51, and a plurality of pinion gears 53 positioned between the sun gear 51 and the ring gear 52. Each pinion gear 53 is rotatable on its own and is supported in a state where it cannot revolve around the sun gear 51.

[0012] As an example of a vehicle configured to connect an engine and two motors by a planetary gear mechanism as described above, the technology disclosed in Japanese Patent Application Laid-Open No. 2022-166473 can be cited.

[0013] The vehicle 500 is equipped with various sensors. For example, the vehicle 500 is equipped with an accelerator sensor 93, a brake sensor 94, and a vehicle speed sensor 95. The accelerator sensor 93 detects the accelerator operation amount, which is the amount of depression of the accelerator pedal in the vehicle 500. The brake sensor 94 detects the brake operation amount, which is the amount of depression of the brake pedal in the vehicle 500. The vehicle speed sensor 95 detects the vehicle speed, which is the traveling speed of the vehicle 500. Each sensor repeatedly transmits the information it has detected to the control device 100 described later.

[0014] Vehicle 500 is equipped with various peripheral monitoring devices. For example, vehicle 500 is equipped with a camera 96 and a receiver 97. The camera 96 images the surroundings of vehicle 500 with the exterior of vehicle 500 as the target. By doing so, the camera 96 acquires an imaging image. The receiver 97 acquires its current position coordinates from global positioning satellites. Each peripheral monitoring device repeatedly transmits the information it has acquired to the control device 100 described below.

[0015] <Control device> Vehicle 500 is equipped with a control device 100. The control device 100 includes a CPU 101 which is an execution unit and a memory 102 which is a storage unit. The memory 102 stores in advance a program in which the processing to be executed by the CPU 101 is described and data necessary for the CPU 101 to execute the program.

[0016] The memory 102 stores in advance course data for a certain specific circuit. For example, the course data divides the circuit into areas at regular intervals of about 10 m and aggregates detailed information for each area. The detailed information includes a position number assigned to each area. The detailed information includes a representative background image and position coordinates in the target area. The detailed information includes a curve number assigned to each curve when the target area is a curve. Further, the detailed information includes stage information indicating whether the target area is the start position, the middle position, or the end position of the curve when the target area is a curve. Note that the course data is not limited to the above example, and any data that can grasp the characteristics of each position of the circuit is acceptable.

[0017] The memory 102 stores in advance driving data. The driving data is an aggregation of target information for each curve in the above specific circuit. The target information is a set of the maximum rotational speed S, the predicted rotational speed R, the designated rotational speed C, and the above curve number.

[0018] The maximum rotational speed S is the target rotational speed of the first MG71 when the vehicle 500 travels along the target curve. Note that the rotational speed of the first MG71 is the same as the rotational speed of the sun gear 41. The maximum rotational speed S is a value determined from the specifications of the first MG71 mounted on the vehicle 500. Specifically, the maximum rotational speed S is the maximum value of the rotational speed that the first MG71 can achieve without imposing an excessive burden on the first MG71. The maximum rotational speed S is a common value for each curve.

[0019] The predicted rotational speed R is the rotational speed of the ring gear 42 on the premise of both operating states where both the accelerator pedal and the brake pedal are depressed. Specifically, the predicted rotational speed R is the rotational speed of the ring gear 42 corresponding to the optimal vehicle speed when the vehicle 500 travels along the target curve in the situation of both operating states. The optimal vehicle speed can be determined from test runs or simulations. The value obtained by converting this predicted rotational speed R according to the gear ratio of the reduction gear 50 becomes the target rotational speed of the second MG72. The predicted rotational speed R varies for each curve.

[0020] The designated rotational speed C is the target rotational speed of the engine 10 when the vehicle 500 travels along the target curve. Note that the rotational speed of the engine 10 is the same as the rotational speed of the carrier 44. The designated rotational speed C is a value determined on a nomogram showing the relationship between the rotational speeds of the sun gear 41, the carrier 44, and the ring gear 42. As shown in FIG. 2, the rotational speeds of the sun gear 41, the carrier 44, and the ring gear 42 are in a relationship where they are connected on a straight line in the nomogram. As shown by the first straight line L1 in FIG. 2, the designated rotational speed C is the rotational speed taken by the carrier 44 when the rotational speed of the sun gear 41 is the maximum rotational speed S and the rotational speed of the ring gear 42 is the predicted rotational speed R on the nomogram. The designated rotational speed C varies for each curve, similar to the predicted rotational speed R.

[0021] <CPU Processing within the Circuit> The CPU 101 controls the first MG 71, the second MG 72, and the engine 10. The CPU 101 controls the torque and rotational speed of the first MG 71 and the second MG 72 through the control of the inverters 90 and 91. Also, the CPU 101 controls the torque and rotational speed of the engine 10 through the control of the ignition timing, fuel injection amount, etc. of the engine 10. The CPU 101 causes the vehicle 500 to travel through these controls. Hereinafter, the processing performed by the CPU 101 when the vehicle 500 is located within the circuit will be described.

[0022] When the vehicle 500 is located within the circuit, the CPU 101 performs the first process and the second process described below. During the travel of the vehicle 500, the CPU 101 continues the first process. In the first process, the CPU 101 repeatedly acquires the travel position of the vehicle 500 within the circuit. Specifically, the CPU 101 identifies the current position within the circuit, for example, by the above position number, based on the current position coordinates acquired by the receiver 97, the captured image acquired by the camera 96, and the course data. At this time, the CPU 101 also identifies the curve number and the stage information of the curve. In the first process, the CPU 101 repeats the identification of such information. The CPU 101 identifying the current position corresponds to the CPU 101 acquiring the travel position.

[0023] When the vehicle 500 reaches a specific travel position, on the condition that it is in the both-operation state, the CPU 101 cancels the normal-time processing related to the control of the first MG 71, the second MG 72, and the engine 10, and starts the second process. The specific travel position is the start position of any curve within the circuit. Note that when the both-operation state is released during the execution of the second process, the CPU 101 ends the second process at that point and returns to the normal-time processing. That is, the CPU 101 performs the second process in a certain area from the start position of the curve until the both-operation state is released. This certain area includes the start position of the curve itself.

[0024] In the second process, first, the CPU 101 acquires target information corresponding to the current curve from the memory 102. Then, the CPU 101 controls the first MG 71, the second MG 72, and the engine 10 based on this target information. Specifically, the CPU 101 controls the first MG 71 so that the rotational speed of the first motor matches the maximum rotational speed S. The CPU 101 controls the second MG 72 so that the rotational speed of the ring gear 42 matches the predicted rotational speed R. The CPU 101 controls the engine 10 so that the rotational speed of the engine 10 matches the specified rotational speed C. The CPU 101 continues to control the first MG 71, the second MG 72, and the engine 10 based on the target information until both operation states are released.

[0025] <Operations and Effects of the Embodiment> The operation and effects of this embodiment will be described. As a premise, when the vehicle 500 is located within the circuit, the CPU 101 prohibits the BOS. Also, in normal processing, the CPU 101 sets an upper limit on the rotational speed of the first MG 71 and the rotational speed of the engine 10 when both operating states are reached. The reason for setting such an upper limit will be explained. Suppose that, after prohibiting the BOS, no upper limit is set on the rotational speed of the first MG 71 and the rotational speed of the engine 10. In this case, when the vehicle 500 is in both operating states, there are the following concerns. Now, assume that the accelerator pedal is depressed while the brake pedal is not depressed. And at this time, in the collinearity diagram of FIG. 2, assume that the rotational speeds of each rotating element satisfy the second straight line L2. Assume that both operating states are reached in this state. At this time, since the accelerator pedal is depressed, the rotational speed of the engine 10 is maintained, while the vehicle speed and thus the rotational speed of the ring gear 42 decrease in response to the operation of the brake pedal. That is, as shown by the arrow P in FIG. 2, the rotational speeds of each rotating element change from a relationship that satisfies the second straight line L2 to a relationship that satisfies the third straight line L3. Along with this, the rotational speed of the sun gear 41 and thus the rotational speed of the first MG 71 become excessively high. And the burden on the first MG 71 increases. In order to suppress such a burden on the first MG 71, in normal processing, when both operating states are reached, the rotational speed of the engine 10 is limited together with the rotational speed of the first MG 71.

[0026] Now, as described above, when both operation states are satisfied when approaching a curve, the CPU 101 of the present embodiment cancels the normal processing and performs the second processing. The advantages of this will be explained. As shown in FIG. 3, at time T1, it is assumed that the driver has depressed only the accelerator pedal among the accelerator pedal and the brake pedal. Also, at time T1, it is assumed that the vehicle 500 is traveling in a straight line. At this time, the CPU 101 controls the rotational speed of the engine 10 to the first value Y1 by normal processing. At a subsequent time T2, it is assumed that the vehicle 500 has approached a curve. At the same time, it is assumed that the driver has depressed the brake pedal in addition to the accelerator pedal, as shown in FIG. 3(c). At this time, if the CPU 101 continues the normal processing, in view of the above-described limitations, as shown by the two-dot chain line in FIG. 3(a), the CPU 101 decreases the rotational speed of the engine 10 to the second value Y2. In this case, when both operation states are released at time T3 after time T2, it takes a relatively long time for the CPU 101 to bring the rotational speed of the engine 10 to a value corresponding to the accelerator operation amount. In this case, the rise of the torque of the engine 10 also becomes slow.

[0027] On the other hand, as shown by the solid line in FIG. 3(a), the CPU 101 of the present embodiment starts the second processing when both operation states are reached at time T2. In this case, the CPU 101 controls the rotational speed of the engine 10 to a specified rotational speed C that is greater than the second value Y2. Since the specified rotational speed C is greater than the second value Y2, after time T3 when both operation states are released, the CPU 101 quickly brings the rotational speed of the engine 10 to a value corresponding to the accelerator operation amount. At the same time, the torque of the engine 10 also quickly rises. Thus, in the configuration of the present embodiment, the response of the engine 10 after returning from both operation states becomes quick. In addition to that, in the present embodiment, when the vehicle 500 is in both operation states, the rotational speed of the first MG 71 is maintained at the maximum rotational speed S. Therefore, the first MG 71 is not excessively burdened.

Description of Reference Numerals

[0028] 10…Engine 40…Power distribution integrated mechanism 41…Sun gear 42…Ring gear 43…Pinion gear 44…Carrier 62…Drive wheel 71…First MG 72…Second MG 96…Camera 100…Control device 101…CPU 102…Memory 500…Vehicle

Claims

【Claim 1】 It is applied to a hybrid vehicle comprising a ring gear interlocked with a drive wheel, a sun gear rotating about the center of the ring gear, a pinion gear interposed between the sun gear and the ring gear and revolving around the sun gear, and a carrier rotating as the pinion gear revolves; an engine having an output shaft connected to the carrier; a first motor interlocked with the sun gear; a second motor interlocked with the ring gear; and a camera for imaging the surroundings. It comprises an execution unit and a storage unit. The storage unit stores in advance, as target information, a predicted rotational speed of the ring gear when the hybrid vehicle travels at a specific driving position in a both-operations state where both an accelerator operation and a brake operation are performed by the driver, a maximum rotational speed which is the maximum value of the rotational speed that the first motor can achieve, and a designated rotational speed which is the rotational speed taken by the carrier when the sun gear is at the maximum rotational speed and the ring gear is at the predicted rotational speed on a collinearity diagram showing the relationship between the rotational speeds of the sun gear, the carrier, and the ring gear. The execution unit performs a first process of acquiring the driving position of the hybrid vehicle based on the captured image of the camera during the driving of the hybrid vehicle, and a second process including a process of acquiring the target information when the hybrid vehicle travels in a certain area including the specific driving position in the both-operations state, and a process of controlling the first motor, the second motor, and the engine based on the acquired target information. A control device for a hybrid vehicle.

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