Hybrid vehicles

Abstract

To enable the engine speed to be maintained above a predetermined speed. [Solution] The hybrid vehicle comprises an engine, a first electric motor capable of generating power which outputs a portion of the power from the engine to a drive shaft connected to the axle by outputting torque, a second electric motor which inputs and outputs power to the drive shaft, a power storage device which exchanges power with the first and second electric motors, and a control device. When charging of the power storage device is expected, the control device releases the output limit of the power storage device and controls the engine, the first electric motor, and the second electric motor so that the engine speed is set to a predetermined speed or higher by the first electric motor.

Description

Technical Field

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[0001] The present disclosure relates to a hybrid vehicle, and more particularly to a hybrid vehicle including a first electric motor capable of generating electricity that outputs a part of the power from the engine to a drive shaft connected to an axle by outputting torque, and a second electric motor that inputs and outputs power to and from the drive shaft.

Background Art

[0002] Conventionally, as this type of hybrid vehicle, when the accelerator is off, the target engine speed is set so as to satisfy the lower limit engine speed corresponding to the virtual shift stage, and the engine is motored by the first electric motor so that the engine speed becomes the target engine speed. Control has been proposed (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above hybrid vehicle, since the output limit (the maximum allowable output power) of the power storage device that supplies power to the first electric motor is small, there are cases where the engine speed cannot be motored down to the lower limit engine speed, and when the accelerator pedal is next depressed, there is a delay in the output of the driving force.

[0005] The main object of the hybrid vehicle of the present disclosure is to be able to maintain the engine speed at a predetermined speed or higher.

Means for Solving the Problems

[0006] The hybrid vehicle of the present disclosure has taken the following means to achieve the above main object.

[0007] The hybrid vehicle disclosed herein is The engine and A first electric motor capable of generating power outputs a portion of the power from the engine to a drive shaft connected to the axle by outputting torque, A second electric motor that inputs and outputs power to the aforementioned drive shaft, A power storage device that exchanges power with the first motor and the second motor, A control device that controls the engine, the first electric motor, and the second electric motor, It is a hybrid vehicle equipped with, When charging of the energy storage device is predicted, the control device releases the output limit of the energy storage device and controls the engine, the first motor, and the second motor so that the rotational speed of the engine is set to a predetermined rotational speed or higher by the first motor. It is characterized by the following:

[0008] The hybrid vehicle of this disclosure includes an engine, a first electric motor capable of generating power which outputs a portion of the power from the engine to a drive shaft connected to the axle by outputting torque, a second electric motor which inputs and outputs power to the drive shaft, a power storage device which exchanges power with the first and second electric motors, and a control device which controls the engine, the first electric motor, and the second electric motor. When charging of the power storage device is expected, the control device of the hybrid vehicle releases the output limit of the power storage device and controls the engine, the first electric motor, and the second electric motor so that the first electric motor keeps the engine speed above a predetermined speed. Because the output limit of the power storage device is released, the engine speed can be kept above a predetermined speed. As a result, the first electric motor can keep the engine speed above a predetermined speed when the accelerator is released.

[0009] Here, "when charging of the energy storage device is predicted" includes situations such as when the second motor is regeneratively controlled when the accelerator is released, or when the navigation system predicts driving downhill or deceleration / stopping due to a red light. Furthermore, the hybrid vehicle of this disclosure may be equipped with a planetary gear mechanism in which three rotating elements are connected to the three axes of the engine's output shaft, the drive shaft, and the first motor's rotation shaft. [Brief explanation of the drawing]

[0010] [Figure 1] This diagram shows a schematic configuration of a hybrid vehicle 20 equipped with a vehicle control device as one embodiment of the present disclosure. [Figure 2] This flowchart shows an example of the output limit release process performed by HVECU70. [Figure 3] This is an explanatory diagram showing an example of a collinear diagram when the output limit Wout is released. [Modes for carrying out the invention]

[0011] Next, embodiments for implementing this disclosure will be described. Figure 1 is a schematic diagram showing the configuration of a hybrid vehicle 20 equipped with an in-vehicle control device as one embodiment of this disclosure. As shown in the figure, the hybrid vehicle 20 of the embodiment includes an engine 22, a planetary gear 30, motors MG1 and MG2, inverters 41 and 42, a battery 50, a hybrid electronic control unit (hereinafter referred to as "HVECU") 70, and a navigation device 90.

[0012] Engine 22 is configured as an internal combustion engine that outputs power using gasoline, diesel fuel, or the like. This engine 22 is operated and controlled by an engine electronic control unit (hereinafter referred to as "engine ECU") 24. Although not shown in the diagram, the engine ECU 24 is configured as a microprocessor centered around a CPU. The engine ECU 24 receives signals from various sensors necessary for operating and controlling the engine 22, and outputs various control signals for operating and controlling the engine 22. The engine ECU 24 communicates with the HVECU 70, and operates and controls the engine 22 based on control signals from the HVECU 70, and outputs data regarding the operating status of the engine 22 to the HVECU 70 as needed.

[0013] The planetary gear 30 is configured as a single-pinion type planetary gear mechanism. The rotor of the motor MG1 is connected to the sun gear of the planetary gear 30. The drive shaft 36, which is connected to the drive wheels 38a and 38b via a differential gear 37, is connected to the ring gear of the planetary gear 30. The crankshaft 26 of the engine 22 is connected to the carrier of the planetary gear 30 via a damper 28.

[0014] Motor MG1 is configured, for example, as a synchronous generator-motor, and as described above, its rotor is connected to the sun gear of the planetary gear 30. Motor MG2 is configured, for example, as a synchronous generator-motor, and its rotor is connected to the drive shaft 36. Inverters 41 and 42 are connected to the battery 50 via a power line 54. Motors MG1 and MG2 are driven by a motor electronic control unit (hereinafter referred to as "motor ECU") 40, which controls the switching of multiple switching elements (not shown) of inverters 41 and 42. Motor ECU 40 (not shown) is configured as a microprocessor centered on a CPU. Motor ECU 40 receives signals from various sensors necessary for driving and controlling motors MG1 and MG2, such as rotational positions θm1 and θm2 from rotational position detection sensors 43 and 44 that detect the rotational position of the rotors of motors MG1 and MG2, and phase currents from current sensors that detect the current flowing through each phase of motors MG1 and MG2. The motor ECU 40 outputs switching control signals to multiple switching elements (not shown) of inverters 41 and 42. The motor ECU 40 communicates with the HVECU 70 and controls the motors MG1 and MG2 based on control signals from the HVECU 70, and outputs data regarding the driving status of motors MG1 and MG2 to the HVECU 70 as needed.

[0015] The battery 50 is configured as, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery. As described above, the battery 50 is connected to inverters 41 and 42 via power lines 54. The battery 50 is managed by an electronic control unit for batteries (hereinafter referred to as "battery ECU") 52. The battery ECU 52 is configured as a microprocessor centered on a CPU, although it is not shown in the diagram. The battery ECU 52 receives signals from various sensors necessary for managing the battery 50, such as the battery voltage Vb from a voltage sensor 51a installed between the terminals of the battery 50, the battery current Ib from a current sensor 51b attached to the output terminal of the battery 50, and the battery temperature Tb from a temperature sensor 51c attached to the battery 50. The battery ECU 52 communicates with the HVECU 70 and outputs data regarding the state of the battery 50 to the HVECU 70 as needed. The battery ECU 52 calculates the state of charge (SOC) based on the integrated value of the battery current Ib from the current sensor 51b. The State of Charge (SOC) is the ratio of the amount of power that can be discharged from the battery 50 to the total capacity of the battery 50. The battery ECU 52 also calculates the input limit Win, which is the maximum allowable input power that can be input to the battery 50, and the output limit Wout, which is the maximum allowable output power that can be output from the battery 50, based on the State of Charge (SOC) and the battery temperature Tb.

[0016] HVECU70, although not shown in the diagram, is configured as a microprocessor centered around a CPU. HVECU70 receives signals from various sensors. For example, it receives the ignition signal from the ignition switch 80, the shift position SP from the shift position sensor 82 which detects the operating position of the shift lever 81, the accelerator opening Acc from the accelerator pedal position sensor 84 which detects the amount the accelerator pedal 83 is pressed, and the brake pedal position BP from the brake pedal position sensor 86 which detects the amount the brake pedal 85 is pressed. It also receives the vehicle speed V from the vehicle speed sensor 88. As mentioned above, HVECU70 communicates with the engine ECU24, motor ECU40, and battery ECU52.

[0017] The navigation device 90 comprises a main unit 92 with a built-in control unit, a GPS antenna 94 that receives information about the vehicle's current location, and a display 96. The main unit 92 has a storage medium (e.g., a hard disk or SSD) that stores map information and the like. The map information includes service information (e.g., tourist information and parking information) and road information for each driving section (e.g., between traffic lights and between intersections) stored in a database. The road information includes distance information, width information, number of lanes information, regional information (urban and suburban), type information (general roads and expressways), gradient information, legal speed limits, number of traffic lights, and turning radius for each curve. The display 96 displays various information such as the vehicle's current location and the planned driving route to the destination, and is configured as a touch panel display that allows the user to input various instructions. When a destination is set by the user operating the display 96, the main unit 92 of the navigation device 90 sets a planned route from the vehicle's current location to the destination based on the map information stored in the main unit 92 and the vehicle's current location and destination from the GPS antenna 94, and displays the set planned route on the display 96 to provide route guidance. The main unit 92 exchanges information with the HVECU 70 through communication.

[0018] In the hybrid vehicle 20 of the embodiment configured in this way, it travels by HV traveling accompanied by the operation of the engine 22 or EV traveling powered by the motor MG2 without the operation of the engine 22.

[0019] Next, the operation of the hybrid vehicle 20 of the embodiment, particularly the operation when the output limit Wout of the battery 550 is released and the engine speed Ne is maintained at a predetermined speed Nref or higher when the charging of the battery 50 is predicted, will be described. FIG. 2 is a flowchart showing an example of the output limit release process executed by the HVECU 70.

[0020] When the output limit release process is executed, the HVECU 70 first inputs data necessary for the process, such as the vehicle speed V, the accelerator opening Acc, the input limit Win of the battery 50, and the output limit Wout (step S100). Next, it determines whether the vehicle is decelerating (step S110) and determines whether regenerative control is being performed on the motor MG2 (step S120). When it is determined that the vehicle is not decelerating or that regenerative control is not being performed on the motor MG2, it is determined that the charging of the battery 50 is not predicted, normal control is executed (step S130), and this process ends. As normal control, basically, the driving required power Pdrv* required for driving is set according to the accelerator opening Acc and the vehicle speed V, and the charge / discharge required power Pb* of the battery 50 is added to this to obtain the engine required power Pe*. The engine 22, the motor MG1, and the motor MG2 are controlled so that the engine 22 outputs the engine required power Pe* on the operation line and travels at the driving required power Pdrv* within the range of the input / output limits Win and Wout of the battery 50.

[0021] When it is determined in steps S110 and S120 that the vehicle is decelerating and regenerative control is being performed on the motor MG2, it is judged that charging of the battery 50 is predicted. The output limit Wout of the battery 50 is released up to the upper limit value (the upper limit value of the rating) (step S140), and the motor MG1 is controlled so that the rotational speed Ne of the engine 22 is maintained at a predetermined rotational speed Nref or higher (step S150), and this process is terminated. Thus, by maintaining the rotational speed Ne of the engine 22 at a predetermined rotational speed Nref or higher, power can be quickly output from the engine 22 when the accelerator pedal 83 is depressed next and acceleration is requested.

[0022] In the hybrid vehicle 20 of the embodiment described above, when the vehicle is decelerating and regenerative control is being performed on the motor MG2, it is judged that charging of the battery 50 is predicted. The output limit Wout of the battery 50 is released up to the upper limit value (the upper limit value of the rating), and the motor MG1 is controlled so that the rotational speed Ne of the engine 22 is maintained at a predetermined rotational speed Nref or higher. Thereby, the rotational speed Ne of the engine 22 is maintained at a predetermined rotational speed Nref or higher, and power can be quickly output from the engine 22 when the accelerator pedal 83 is depressed next and acceleration is requested.

[0023] In the hybrid vehicle 20 of the embodiment, when it is judged that charging of the battery 50 is predicted when the vehicle is decelerating and regenerative control is being performed on the motor MG2, the output limit Wout of the battery 50 is released up to the upper limit value, and the motor MG1 is controlled so that the rotational speed Ne of the engine 22 is maintained at a predetermined rotational speed Nref or higher. However, when the navigation device 90 predicts traveling on a downhill road, deceleration or stop due to a red signal, etc., and it is judged that charging of the battery 50 is predicted, the output limit Wout of the battery 50 may be released up to the upper limit value, and the motor MG1 may be controlled so that the rotational speed Ne of the engine 22 is maintained at a predetermined rotational speed Nref or higher.

[0024] " The correspondence between the main elements of the embodiment and the main elements of the invention described in the section on means for solving the problem will be explained. In the embodiment, engine 22 corresponds to "engine", motor MG1 corresponds to "first electric motor", motor MG2 corresponds to "second electric motor", battery 50 corresponds to "energy storage device", and engine ECU 24, motor ECU 40, and HVECU 70 correspond to "control device".

[0025] Furthermore, the correspondence between the main elements of the embodiment and the main elements of the invention described in the section on means for solving the problem is merely an example to specifically explain the form in which the embodiment implements the invention described in the section on means for solving the problem, and does not limit the elements of the invention described in the section on means for solving the problem. In other words, the interpretation of the invention described in the section on means for solving the problem should be based on the description in that section, and the embodiment is merely one specific example of the invention described in the section on means for solving the problem.

[0026] While embodiments of this disclosure have been described above, this disclosure is not limited in any way to these embodiments, and can of course be implemented in various forms without departing from the gist of this disclosure. [Industrial applicability]

[0027] This disclosure can be used in industries such as the hybrid vehicle manufacturing industry. [Explanation of Symbols]

[0028] 20 Hybrid vehicle, 22 Engine, 24 Engine electronic control unit (Engine ECU), 40 Motor electronic control unit (Motor ECU), 41, 42 Inverter, 50 Battery, 52 Battery electronic control unit (Battery ECU52), 70 Hybrid electronic control unit (HVECU), 90 Navigation system, MG1, MG2 Motor.

Claims

[Claim 1] The engine and A first electric motor capable of generating power outputs a portion of the power from the engine to a drive shaft connected to the axle by outputting torque, A second electric motor that inputs and outputs power to the aforementioned drive shaft, A power storage device that exchanges power with the first motor and the second motor, A control device that controls the engine, the first electric motor, and the second electric motor, It is a hybrid vehicle equipped with, When charging of the energy storage device is predicted, the control device releases the output limit of the energy storage device and controls the engine, the first motor, and the second motor so that the rotational speed of the engine is set to a predetermined rotational speed or higher by the first motor. A hybrid vehicle characterized by the following features.

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