Control device

Abstract

To provide a control device that can secure necessary driving force, while securing ride comfort.SOLUTION: A control device according to the present invention is a control device of a vehicle which is equipped with a first clutch 21 through which an engine 11 can be connected to and disconnected from a motor 121, a second clutch 22 through which a transmission 13 can be connected to and disconnected from the motor 121, and a battery 12 connected to the motor 121, which when a charging rate of the battery 12 falls to a predetermined value or less during travelling, brings the second clutch 22 into a slip state to increase a rotation speed and torque of the engine 11.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a control device in an automobile.

Background Art

[0002] In recent years, in order to reduce the emission of carbon dioxide, environmentally friendly automobiles have been manufactured. For example, Patent Document 1 discloses a four-wheel drive vehicle in which the front and rear wheels can be driven by motors. It is also disclosed that an engine is provided and driving with the engine and the motor is possible.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The inventor has found the following problems regarding an automobile using an engine and a motor. When driving in a situation where the required driving force cannot be ensured only by the engine, the battery power is used to drive the motor. However, if such a situation continues, the battery power will be insufficient, and it will fall into a state where the required driving force of the motor cannot be realized. As a countermeasure against such a state, conventionally, the engine torque in a region regulated by NV (Noise & Vibration) etc. has been used, or a deceleration shift has been performed. However, such a method will deteriorate the ride comfort of the driver.

[0005] The present invention has been made in view of such circumstances, and an object thereof is to provide a control device capable of ensuring the required driving force while ensuring the ride comfort.

Means for Solving the Problems

[0006] The control device according to the present invention is a first clutch that enables connection and disconnection between the engine and the motor, a second clutch that enables intermittent connection and disconnection between the transmission and the motor, and a battery connected to the motor, and is a control device for a vehicle, when the charging rate of the battery becomes equal to or lower than a predetermined value during traveling, the second clutch is set in a slip state to increase the rotational speed and torque of the engine. It is characterized by the above.

[0007] With this diagnostic device, it is possible to ensure the necessary driving force while ensuring a comfortable ride.

[0008] When the temperature of the second clutch is equal to or higher than a predetermined temperature, the second clutch is changed from a slip state to an engaged state, and the rotational speed and torque of the engine before the slip state are maintained. This can avoid a situation where the vehicle is damaged and cannot travel.

Advantages of the Invention

[0009] According to the present invention, it is possible to provide a control device capable of ensuring the necessary driving force while ensuring a comfortable ride.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0011] Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments. Also, for clarity of explanation, the following description and drawings are simplified as appropriate.

[0012] (First Embodiment) <System Configuration> First, the system configuration of the vehicle according to the first embodiment will be described. FIG. 1 is a system configuration diagram according to the first embodiment. The vehicle 10 includes an engine 11, a battery 12, motors 121 and 122, an automatic transmission 13, a first clutch 21 and a second clutch 22, a control device 220 for the second clutch, and wheels 41, 42, 43, 44. The automatic transmission 13 is an example of a transmission and may be a manual transmission.

[0013] The engine 11 and the motor 121 can be connected and disconnected via the first clutch 21. The first clutch 21 is composed of an external gear and an internal gear. That the first clutch 21 is engaged means that the external gear and the internal gear in the first clutch 21 are meshed. However, the first clutch 21 is not limited to a meshing clutch between gears and may be a friction clutch between flanges or the like. When the first clutch 21 is engaged, the engine 11 and the motor 121 are connected, so the driving force of the engine 11 is transmitted to the motor 121. On the other hand, when the first clutch 21 is not engaged, the engine 11 and the motor 121 are disconnected, so the driving force of the engine 11 is not transmitted to the motor 121. The automatic transmission 13 and the motor 121 can be connected and disconnected via the second clutch 22. The second clutch 22 is, for example, a friction clutch. When the second clutch 22 is engaged, the automatic transmission 13 and the motor 121 are connected, so the driving force of the motor 121 is transmitted to the automatic transmission 13. On the other hand, when the second clutch 22 is not engaged, the automatic transmission 13 and the motor 121 are disconnected, so the driving force of the motor 121 is not transmitted to the automatic transmission 13.

[0014] When the charging rate of the battery 12 becomes equal to or lower than a predetermined value during running, the control device 220 of the second clutch sets the second clutch 22 in a slip state and increases the rotational speed and torque of the engine 11. Further, when the temperature of the second clutch 22 is equal to or higher than a predetermined temperature, the second clutch 22 is changed from the slip state to the engaged state, and the rotational speed and torque of the engine 11 before the slip state are maintained.

[0015] The battery 12 is connected to the motor 121 via the inverter 123. The inverter 123 controls the output of the electric power transmitted from the battery 12 to the motor 121. The battery 12 is connected to the motor 122 via the inverter 124. The inverter 124 controls the output of the electric power transmitted from the battery 12 to the motor 122. Here, the vehicle 10 in FIG. 1 is provided with two motors, the motor 121 and the motor 122, but only one of the motors may be used.

[0016] The wheel 41 and the wheel 44 are integrally connected by the axle 51. On the other hand, the wheel 42 and the wheel 43 are integrally connected by the axle 61. In FIG. 1, it is assumed that the axle 51 side is the forward direction and the axle 61 side is the reverse direction. That is, the wheels 41 and 44 are the front wheels, and the wheels 42 and 43 are the rear wheels.

[0017] The automatic transmission 13 is connected to the axle 51 on the front wheel side. The driving force of the motor 121 is transmitted to the axle 51 via the automatic transmission 13. On the other hand, the driving force of the motor 122 is transmitted to the axle 61 on the rear wheel side.

[0018] Next, with reference to FIGS. 2 to 5, the driving forces of the engine 11 and the motor 121 during the running of the vehicle 10 will be described. In FIGS. 2 to 5, in order to clarify which of the engine 11, the motor 121, the first clutch 21, the second clutch 22, and the inverter 123 is functioning, the corresponding parts are appropriately filled in.

[0019] FIG. 2 is a system configuration diagram of the vehicle 10 when the vehicle 10 is running by the motor 121. During EV running with only the motor 121, the engine 11 and the motor 121 are disconnected by disengaging the first clutch 21, and the engine 11 completely stops. On the other hand, in order to engage the second clutch 22, the driving force of the motor 121 is transmitted to the automatic transmission 13. At this time, the electricity of the battery 12 is output-controlled by the inverter 123 and transmitted to the motor 121. That is, in this state, the battery 12 is discharging.

[0020] FIG. 3 is a system configuration diagram of the vehicle 10 when the vehicle 10 is running by the engine 11. By connecting the first clutch 21 and the second clutch 22, the driving force from the engine 11 is transmitted to the automatic transmission 13. At this time, the electricity generated by the power generation action of the motor 121 flows to the battery 12. Thereby, the battery 12 is charged. That is, the battery 12 is regenerating energy.

[0021] FIG. 4 is a system configuration diagram of the vehicle 10 when the vehicle 10 is running by the engine 11 and the motor 121. By connecting the first clutch 21 and the second clutch 22, both driving forces in the engine 11 and the motor 121 are transmitted to the automatic transmission 13. At this time, the electrical energy of the battery 12 is output-controlled by the inverter 123 and transmitted to the motor 121. That is, the battery 12 is discharging.

[0022] FIG. 5 is a system configuration diagram of the vehicle 10 when the vehicle 10 is decelerating. When the vehicle 10 is decelerating during traveling, the first clutch 21 is disengaged, so that the engine 11 and the motor 121 are disengaged, and the engine 11 completely stops. At this time, since the engine 11 is completely disengaged, the rotational speed of the engine 11 becomes zero, and the engine 11 is in a state without rotational resistance. At this time, the electricity generated by the power generation action of the motor 121 flows to the battery 12. Thereby, the battery 12 is charged. That is, the battery 12 is regenerating energy.

[0023] <System Operation> Next, the system operation when the vehicle 10 is traveling in a low rotation high load region or the like will be described. Here, the low rotation high load region is assumed to be, for example, a slope. When staying in the driving region using the battery 12, the balance of electrical energy cannot be achieved and the state of charge (SOC) decreases. Therefore, there is a possibility that the necessary assist amount cannot be ensured. Therefore, in the vehicle 10 according to the present embodiment, the second clutch control device 220 makes the second clutch 22 slip. Slipping the clutch means a slip state in which the friction clutches slip and transmit torque while having differential rotation. Thereby, by operating the engine at a higher output than the normal equilibrium state, the balance of the electrical energy of the battery 12 can be improved without sacrificing the NV (Noise & Vibration) of the engine. Sacrificing NV implies that noise and vibration are generated in a direction that makes the riding comfort unpleasant.

[0024] FIG. 6 is a diagram showing changes in the power of the battery 12, the state of charge (SOC) of the battery 12, the engine speed (Ne), the input speed (Natin), the torque (Te), and the temperature (T22) of the second clutch 22 when the vehicle 10 is traveling on an uphill slope, which is a low-speed and high-load region. In the following description of FIG. 6, the abbreviations shown in parentheses are used. Note that Natin is the rotational speed on the automatic transmission 13 side of the second clutch 22 and is determined by the initial speed and the gear position. In FIG. 6, the section A-B is a sloped road, and the vehicle 10 is traveling uphill. Point C is the point at which the control device 220 of the second clutch starts to slip the second clutch 22. Also, point D is the point at which the control device 220 of the second clutch stops slipping the second clutch 22.

[0025] The change in the power of the battery 12 in FIG. 6 will be described. In the section A-C on the slope, since the vehicle 10 is traveling using the motor 121, the power of the battery 12 is a constant value P0. That is, in the section A-C on the slope, the battery 12 is in a discharging state. Here, at point C, when the control device 220 of the second clutch causes the second clutch 22 to slip, the torque on the engine side increases and driving force is generated, so the power of the battery 12 decreases and becomes a power having a constant value P1 smaller than P0. At this time, also in the section C-D, the battery 12 is in a discharging state.

[0026] The change in the SOC of the battery 12 in FIG. 6 will be described. In the section A-C on the slope, since the vehicle 10 is traveling using the motor 121, the SOC of the battery 12 decreases. Here, at point C, when the control device 220 of the second clutch causes the second clutch 22 to slip, the torque on the engine side increases, and while the battery 12 is being used, regeneration occurs. Therefore, in the section C-D, the balance of the battery 12 improves, and the SOC of the battery 12 becomes a constant value SOC0.

[0027] The changes in Ne and Natin in FIG. 6 will be described. In the A-C section on the slope road, the first clutch 21 and the second clutch 22 in the vehicle 10 are connected. Therefore, Ne and Natin are at the same constant rotational speed R0. Here, at point C, when the second clutch 22 is slipped by the control device 220 of the second clutch, Ne rises to the rotational speed R1. In the C-D section, Ne has a constant value of the rotational speed R1. At point D, when the control device 220 of the second clutch stops slipping the second clutch 22, Ne decreases again to the rotational speed R0 and becomes constant. On the other hand, since Natin is governed by the initial speed and the gear stage, it remains at a constant rotational speed R0 in the A-D section.

[0028] The change in Te in FIG. 6 will be described. Te in FIG. 6 corresponds to the system torque obtained by combining the engine torque and the torque by the motor. In the A-C section on the slope road, Te shows a constant value Te0. Here, at point C, when the second clutch 22 is slipped by the control device 220 of the second clutch, the Ne rotational speed rises and the engine torque increases. On the other hand, the torque by the motor decreases because the power by the battery 12 decreases. At this time, since the increase in the engine torque is larger than the decrease in the torque by the motor, the system torque rises to Te1. In the C-D section, Te has a constant value of Te1. At point D, when the control device 220 of the second clutch stops slipping the second clutch 22, Ne decreases again to the rotational speed R0, so the engine torque decreases. That is, Te also decreases to T0 in conjunction and becomes constant.

[0029] A description will be given of the change in T22 in FIG. 6. In the section A-C on the slope, T22 is a constant value T0. Here, at point C, when the control device 220 of the second clutch shifts to a state where the second clutch 22 is slipping, T22 increases due to the friction when the clutch slips. At this time, when the temperature of T22 rises and reaches the temperature TL in section D, the control device 220 of the second clutch stops slipping the second clutch 22. That is, the second clutch 22 is changed from a slip state to an engaged state, and the rotational speed and torque of the engine 11 before slipping are maintained. Thereby, T22 can be prevented from reaching destruction without increasing the temperature above the temperature TL. That is, when T22 reaches a predetermined value or more, the control device 220 of the second clutch stops the state where the second clutch 22 is slipping.

[0030] Subsequently, a description will be given of the control method for the second clutch 22. FIG. 7 is a flowchart showing the control method for the second clutch 22 according to the first embodiment. Note that the same abbreviations as in FIG. 6 are used for the charge rate, the rotational speed of the engine 11, and the rotational speed input to the automatic transmission 13.

[0031] First, the control device 220 of the second clutch checks whether the electrical energy balance of the battery 12 is less than 0 when the vehicle 10 is running (step ST1). That is, the difference between the electrical energy regenerated to the battery 12 and the electrical energy discharged to the motor 121 is checked. If the electrical energy balance is 0 or more (step ST1 NO), the control device 220 of the second clutch repeats step ST1. If the electrical energy balance is less than 0 (step ST1 YES), the control device 220 of the second clutch checks whether the SOC of the battery 12 is decreasing, so whether the SOC is less than or equal to the reference value SOC0. If the SOC of the battery 12 is greater than SOC0 (step ST2 NO), the control device 220 of the second clutch repeats from step ST1 again. On the other hand, if the SOC of the battery 12 is less than or equal to SOC0 (step ST2 YES), the control device 220 of the second clutch executes step ST3.

[0032]

[0032] In step ST3, the power in the engine 11 is set to a set value obtained by adding the improvement in the electrical energy balance to the current power in the engine 11 and the energy loss (α) consumed in other parts. Here, the improvement in the electrical energy balance indicates the energy that can no longer be supplemented by the motor while the vehicle 10 is running.

[0033] Subsequent to step ST3, the control device 220 of the second clutch sets the engine operating point Ne. (Step ST4) At this time, the engine operating point Ne is set taking into account the loss when the clutch is slipped.

[0034] Here, in step ST4, the control device 220 of the second clutch slips the second clutch 22 by the difference between the set engine operating point Ne and Natin. (Step ST5)

[0035]

[0033] Subsequent to step ST5, the control device 220 of the second clutch checks whether the energy balance in the running region of the vehicle 10 is 0 or more. (Step ST6) When the energy balance is 0 or more, since the electrical energy of the battery 12 is being regenerated, the control device 220 of the second clutch changes the second clutch 22 from the slip state to the engaged state and maintains the rotational speed and torque of the engine before slipping. (Step ST6 YES) On the other hand, when the energy balance is still less than 0 (Step ST6 NO), the control device 220 of the second clutch keeps the second clutch 22 in the slip state. At this time, the temperature of the second clutch 22 rises due to the friction when the second clutch 22 slips. Therefore, following step ST6, the control device 220 of the second clutch determines whether the temperature T22 of the second clutch 22 is less than or equal to the set temperature TL (step ST7). If the temperature T22 of the second clutch 22 is less than the set temperature TL (step ST7 YES), the control device 220 of the second clutch keeps the second clutch 22 in a slip state and repeats from step ST6. On the other hand, if the temperature T22 of the second clutch 22 is greater than or equal to the set temperature TL, the control device 220 of the second clutch changes the second clutch 22 from a slip state to an engaged state and maintains the engine speed and torque before slipping (step ST7 NO). Thereby, T22 does not become a temperature equal to or higher than the temperature TL, and it is possible to prevent reaching destruction.

[0036] When the power balance of the control device according to the first embodiment becomes less than 0, it controls to slip the second clutch 22. Therefore, by operating the engine at a higher output than the normal equilibrium state, it is possible to improve the power balance of the battery 12 without sacrificing the NV of the engine.

[0037] Since the control device according to the first embodiment stops controlling to slip the second clutch 22 when the temperature of the second clutch 22 becomes equal to or higher than a predetermined temperature, it is possible to prevent destruction due to an increase in the temperature of the second clutch 22.

Explanation of Reference Numerals

[0038] 10 Vehicle 11 Engine 12 Battery 13 Automatic Transmission 21 First Clutch 22 Second Clutch 41, 42, 43, 44 Wheels 51, 61 Axles 121, 122 Motors 123, 124 Inverters 220 Control Device of Second Clutch

Claims

【Claim 1】 a first clutch that enables connection and disconnection between the engine and the motor; a second clutch that enables connection and disconnection between the transmission and the motor; a battery connected to the motor, wherein the control device of the vehicle includes: when the charging rate of the battery becomes equal to or less than a predetermined value during traveling, the second clutch is brought into a slip state to increase the rotational speed and torque of the engine; when the temperature of the second clutch is equal to or higher than a predetermined temperature: the second clutch is changed from the slip state to the engaged state, and the rotational speed and torque of the engine before the slip state are maintained; a control device.

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