Hybrid vehicles

Abstract

It suppresses unusual noises that may cause discomfort to the occupants. [Solution] A hybrid vehicle comprising an engine, a first motor, a planetary gear with three rotating elements connected to the engine, the first motor, and a drive shaft connected to the axle, a second motor connected to the drive shaft, and a control device that controls the engine and the first and second motors to run with intermittent engine operation, wherein the control device controls the engine and the first motor to run the engine continuously at a rotational speed of a predetermined speed or higher when the vehicle speed is above a predetermined speed and the sound pressure inside the vehicle exceeds a predetermined pressure.

Description

Technical Field

[0007] ,

[0001] This disclosure relates to a hybrid vehicle.

Background Art

[0002] Conventionally, as this type of hybrid vehicle, there has been proposed one including an engine, a first motor (first electric motor), a planetary gear (front planetary gear mechanism) to which three rotating elements are connected to the engine, the first motor, and a drive shaft connected to an axle, and a second motor (second electric motor) connected to the drive shaft (see, for example, Patent Document 1). In this hybrid vehicle, by changing the operating point of the engine so that the rotational speed of the engine increases and the output of the engine decreases as the rotational speed of the engine increases, abnormal noises such as gear meshing noises are suppressed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above hybrid vehicle, when the vehicle speed is equal to or higher than a predetermined vehicle speed, if the operating point of the engine is changed so that the rotational speed of the engine increases and the output of the engine decreases, on the contrary, abnormal noises may occur, giving a sense of discomfort to the passengers.

[0005] The hybrid vehicle of this disclosure mainly aims to suppress abnormal noises that give a sense of discomfort to the passengers.

Means for Solving the Problems

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

[0007] The hybrid vehicle of this disclosure is The engine and First motor and A planetary gear with three rotating elements connected to the engine, the first motor, and the drive shaft connected to the axle, A second motor connected to the aforementioned drive shaft, A control device that controls the engine and the first and second motors so that the vehicle runs with intermittent operation of the engine, A hybrid vehicle equipped with, The control device controls the engine and the first motor to continue operating the engine at a rotational speed of a predetermined speed or higher when the vehicle speed is above a predetermined speed and the sound pressure inside the vehicle exceeds a predetermined pressure. This is the gist of it.

[0008] In the hybrid vehicle of this disclosure, when the vehicle speed is above a predetermined speed and the sound pressure inside the vehicle exceeds a predetermined pressure, the engine and the first motor are controlled to continue operating at a rotational speed above a predetermined speed. The inventors have found that abnormal noise occurs when the vehicle speed is below a predetermined speed and the engine rotational speed is below a predetermined speed. Also, when the sound pressure inside the vehicle exceeds a predetermined pressure, occupants are likely to feel uncomfortable. Therefore, when the vehicle speed is above a predetermined speed and the sound pressure inside the vehicle exceeds a predetermined pressure, the engine and the first motor are controlled to continue operating at a rotational speed above a predetermined speed, thereby suppressing abnormal noise that may cause discomfort to occupants. Here, "predetermined speed" may be the lower limit of the speed at which abnormal noise occurs due to the meshing of the planetary gears. "Predetermined rotational speed" may be the idle speed of the engine. "Predetermined pressure" may be the upper limit of the range of sound pressure inside the vehicle that occupants can tolerate.

[0009] In the hybrid vehicle of this disclosure, the control device may control the engine and the first motor to continue operating the engine at a rotational speed of a predetermined speed or higher when the vehicle speed is between a first speed (as a predetermined speed) and a second speed (higher than the first speed), and the sound pressure inside the vehicle exceeds the predetermined pressure. Even if abnormal noise occurs due to the meshing of the planetary gears, at high vehicle speeds, the abnormal noise is drowned out by the driving noise, making it difficult for occupants to recognize the abnormal noise. Therefore, by controlling the engine and the first motor to continue operating the engine at a rotational speed of a predetermined speed or higher when the vehicle speed is between a first speed (as a predetermined speed) and a second speed (higher than the first speed), and the sound pressure inside the vehicle exceeds the predetermined pressure, the engine can be continuously operated at a rotational speed of a predetermined speed or higher at a vehicle speed where the abnormal noise is not drowned out by the driving noise, thereby suppressing the abnormal noise. Here, the "second speed" may be the lower limit of the vehicle speed at which the abnormal noise is not drowned out by the driving noise. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram showing the configuration of a hybrid vehicle equipped with the control device of this embodiment. [Figure 2] This flowchart shows an example of a processing routine executed by HVECU. [Figure 3] This is an explanatory diagram illustrating an example of the relationship between engine speed, vehicle speed, and the meshing frequency of the planetary gears. [Modes for carrying out the invention]

[0011] Embodiments of this disclosure will be described with reference to the drawings. Figure 1 is a schematic diagram showing the configuration of a hybrid vehicle 20 equipped with the control device of this embodiment. The hybrid vehicle 20 of this embodiment includes an engine 22, an engine electronic control unit (hereinafter referred to as "engine ECU") 24, a planetary gear 30, motors MG1 and MG2 (first and second motors), an electronic control unit (hereinafter referred to as "motor ECU") 40, inverters 41 and 42, a battery 50 as an energy storage device, and a hybrid electronic control unit (hereinafter referred to as HVECU) 70.

[0012] Engine 22 is configured as an internal combustion engine that outputs power using, for example, gasoline or diesel fuel. Engine 22 is controlled by the engine ECU 24.

[0013] The engine ECU 24, though not shown, is configured as a microprocessor centered around a CPU. In addition to the CPU, it includes a ROM for storing processing programs, a RAM for temporarily storing data, a flash memory for storing and retaining data, input / output ports, and communication ports. Signals from various sensors necessary for controlling the operation of the engine 22 are input to the engine ECU 24 via its input ports. Examples of signals input to the engine ECU 24 include the crank angle θcr from a crank position sensor (not shown) that detects the rotational position of the crankshaft 23 of the engine 22, and the coolant temperature from a water temperature sensor (not shown) that detects the coolant temperature of the engine 22. Various control signals for controlling the operation of the engine 22 are output from the engine ECU 24 via its output ports. Examples of signals output from the engine ECU 24 include control signals to the throttle valve, control signals to the fuel injector, and control signals to the spark plug. The engine ECU 24 is connected to the HVECU 70 via its communication port. The engine ECU 24 calculates the rotational speed Ne of the engine 22 based on the crank angle θcr of the engine 22 from the crank position sensor.

[0014] 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 39a and 39b via a differential gear 38, is connected to the ring gear of the planetary gear 30. The crankshaft 23 of the engine 22 is connected to the carrier of the planetary gear 30 via a damper 28.

[0015] 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 used to drive motors MG1 and MG2 and are connected to the battery 50 via the power line 54. Motors MG1 and MG2 are rotationally driven by the motor ECU 40, which controls the switching of multiple switching elements (not shown) of inverters 41 and 42.

[0016] The motor ECU 40, although not shown in the diagram, is configured as a microprocessor centered around a CPU. In addition to the CPU, it includes a ROM for storing processing programs, a RAM for temporarily storing data, a flash memory for storing and retaining data, input / output ports, and communication ports. Signals from various sensors necessary for driving and controlling motors MG1 and MG2 are input to the motor ECU 40 via its input ports. Examples of signals input to the motor ECU 40 include the rotational positions θm1 and θm2 of the rotors of motors MG1 and MG2 from a rotational position sensor (not shown) that detects the rotational position of the rotors of motors MG1 and MG2, and the phase currents of each phase of motors MG1 and MG2 from a current sensor (not shown) that detects the phase current flowing through each phase of motors MG1 and MG2. Switching control signals to multiple switching elements (not shown) of inverters 41 and 42 are output from the motor ECU 40 via its output ports. The motor ECU 40 is connected to the HVECU 70 via its communication port. The motor ECU 40 calculates the rotational speeds Nm1 and Nm2 of motors MG1 and MG2 based on the rotational positions θm1 and θm2 of the rotors of motors MG1 and MG2, as measured by the rotational position sensors.

[0017] The battery 50 is configured as, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery, and as described above, is connected to inverters 41 and 42 via power lines 54. This battery 50 is managed by an electronic control unit for batteries (hereinafter referred to as "battery ECU") 52.

[0018] The battery ECU 52 is configured as a microprocessor centered around a CPU, although not shown in the figure. In addition to the CPU, it includes a ROM for storing processing programs, a RAM for temporarily storing data, a flash memory for retaining data storage, input / output ports, and communication ports. Signals from various sensors necessary for managing the battery 50 are input to the battery ECU 52 via the input ports. Examples of signals input to the battery ECU 52 include the voltage Vb of the battery 50 from a voltage sensor (not shown) attached between the terminals of the battery 50, the current Ib of the battery 50 from a current sensor (not shown) attached to the output terminal of the battery 50, and the temperature Tb of the battery 50 from a temperature sensor (not shown) attached to the battery 50. The battery ECU 52 is connected to the HV ECU 70 via a communication port. The battery ECU 52 calculates the state of charge SOC of the battery 50 based on the integrated value of the current Ib of the battery 50 from the current sensor. The state of charge SOC is the ratio of the capacity of the electric power that can be discharged from the battery 50 to the total capacity of the battery 50.

[0019] Although not shown in the diagram, the HVECU70 is configured as a microprocessor centered around a CPU. In addition to the CPU, it includes ROM for storing processing programs, RAM for temporarily storing data, flash memory for storing and retaining data, input / output ports, and communication ports. Signals from various sensors are input to the HVECU70 via its input ports. Examples of signals input to the HVECU70 include the ignition signal from the ignition switch 80 and the shift position SP from the shift position sensor 82, which detects the operating position of the shift lever 81. Other examples include the accelerator opening Acc from the accelerator pedal position sensor 84, which detects the amount the accelerator pedal 83 is pressed, the brake pedal position BP from the brake pedal position sensor 86, which detects the amount the brake pedal 85 is pressed, the vehicle speed V from the vehicle speed sensor 88, and the sound pressure Sp from the microphone 90 located inside the passenger compartment. As mentioned above, the HVECU70 is connected to the engine ECU24, motor ECU40, and battery ECU52 via its communication ports.

[0020] In the hybrid vehicle 20 of this embodiment, the engine 22 and motors MG1 and MG2 are controlled by coordinated control of the HVECU 70, engine ECU 24, and motor ECU 40 to perform hybrid driving (HV driving) or electric driving (EV driving). HV driving is driving with the engine 22 running. EV driving is driving with the engine 22 stopped (without driving). In other words, in the hybrid vehicle 20, the engine 22 and motors MG1 and MG2 are controlled to drive while the engine 22 is running intermittently.

[0021] During HV driving, the HV ECU 70 first sets the required torque Td* for driving (required for the drive shaft 37) based on the accelerator opening Acc and the vehicle speed V, and sets the required power Pd* for driving based on the set required torque Td* and the rotational speed Nd of the drive shaft 37 (the rotational speed Nm2 of the motor MG2). Subsequently, based on the required power Pd* and the charge / discharge required power Pb* based on the state of charge SOC of the battery 50, the required power Pe* of the engine 22 is set, and when the required power Pe* is output from the engine 22 and the required torque Td* is output to the drive shaft 37 within the range of the input / output limits Win and Wout of the battery 50, the target rotational speed Ne* and target torque Te* of the engine 22 and the torque commands Tm1* and Tm2* of the motors MG1 and MG2 are set. Then, the target rotational speed Ne* and target torque Te* of the engine 22 are transmitted to the engine ECU 24, and the torque commands Tm1* and Tm2* of the motors MG1 and MG2 are transmitted to the motor ECU 40. The engine ECU 24 performs operation control (such as intake air amount control, fuel injection control, ignition control, etc.) of the engine 22 so that the engine 22 is operated based on the target rotational speed Ne* and target torque Te*. The motor ECU 40 controls the inverters 41 and 42 so that the motors MG1 and MG2 are driven based on the torque commands Tm1* and Tm2*.

[0022] During HV driving, when the stop condition of the engine 22 is satisfied, such as when the vehicle speed V is less than the threshold value Vref1, the required torque Td* is less than the threshold value Tdref, and the required power Pd* is less than the threshold value Pdref, the engine 22 is stopped and the vehicle shifts to EV driving.

[0023] During EV driving, the HV ECU 70 first sets the required torque Td* in the same manner as HV driving. Subsequently, the value 0 is set for the torque command Tm1* of the motor MG1, and the required torque Td* is set for the torque command Tm2* of the motor MG2 so that the required torque Td* is output to the drive shaft 37. Then, the torque commands Tm1* and Tm2* of the motors MG1 and MG2 are transmitted to the motor ECU 40. The motor ECU 40 controls the inverters 41 and 42 so that the motors MG1 and MG2 are driven by the torque commands Tm1* and Tm2*.

[0024] In EV driving, when the conditions for starting the engine 22 are met, such as when the vehicle speed V reaches a threshold Vref1 (starting judgment vehicle speed), when the requested torque Td* reaches a threshold Tdref, or when the requested power Pd* calculated in the same way as in HV driving reaches a threshold Pdref, the engine 22 is started with cranking by the motor MG1, and the vehicle transitions to HV driving. When starting the engine 22, the motor MG1 (inverter 41) is controlled by setting the cranking torque Tcr for cranking the engine 22 to the torque command Tm1* of the motor MG1. For the engine 22, fuel injection control and ignition control are started when the rotational speed Ne of the engine 22 reaches a threshold Nsteg or higher. For the motor MG2 (inverter 42), the torque command Tm2* is set so that the requested torque Td* is output to the drive shaft 37. The above-described control in HV driving and EV driving is sometimes referred to as "normal control".

[0025] Next, the operation of the hybrid vehicle 20 of the embodiment configured in this way, particularly the operation when suppressing abnormal noises, will be described. Figure 2 is a flowchart showing an example of a processing routine executed by the HVECU 70. This routine is repeatedly executed at predetermined intervals (for example, every few milliseconds) during HV driving.

[0026] When this routine is executed, the HVECU70 CPU first receives the vehicle speed V detected by the vehicle speed sensor 88, the sound pressure Sp from the microphone 90, and the flag F (S100). Flag F is a flag that is set to a value of 1 when the abnormal noise suppression control described later is being performed. Flag F is set to an initial value of 0 when the ignition switch 80 is turned on.

[0027] Next, the HVECU70's CPU determines whether flag F is valued at 1 (S110). If flag F is valued at 0, the HVECU70's CPU determines whether the vehicle speed V input in S100 is within the range of a first speed (predetermined speed) V1 or higher and a second speed V2 or lower (S120). The first speed V1 is the lower limit of vehicle speed at which abnormal noise occurs due to the meshing of the planetary gear 30, for example, 70 km / h, 75 km / h, 80 km / h, etc. The second speed V2 is the lower limit of vehicle speed at which abnormal noise due to the meshing of the planetary gear 30 is not drowned out by the driving noise, for example, 105 km / h, 110 km / h, 115 km / h, etc. The abnormal noise due to the meshing of the planetary gear 30 is caused by variations in the manufacturing precision of the tooth surface in the planetary gear 30, which results in the tooth tips becoming convex. The first speed V1 is determined in advance through experiments, analyses, and machine learning as the lower limit of the vehicle speed at which these abnormal noises occur.

[0028] If, in S120, the HVECU70 CPU determines that no abnormal noise will occur in the planetary gear 30 even if the above-mentioned normal control is performed, or that even if abnormal noise occurs due to the meshing of the planetary gear 30, it will be drowned out by the driving noise and the occupants will not be able to perceive the abnormal noise. In this case, the CPU performs the above-mentioned normal control (S140) and terminates this routine.

[0029] In S120, the HVECU70 CPU determines that an abnormal noise is occurring due to the meshing of the planetary gear 30 when the vehicle speed V is within the range of a first speed V1 or higher and a second speed V2 or lower, and determines whether the sound pressure Sp exceeds a predetermined pressure Spth (S130). The predetermined pressure Spth is a sound pressure that has been determined in advance through experiments, analysis, machine learning, etc., as the upper limit of the range of sound pressure inside the vehicle that occupants can tolerate.

[0030] If the sound pressure Sp does not exceed the predetermined pressure Spth in S130, the HVECU70 CPU determines that even if an abnormal noise occurs, it is within the occupant's tolerance range, and executes the normal control described above (S140), then terminates this routine.

[0031] In S130, when the sound pressure Sp exceeds a predetermined pressure Spth, the HVECU70 CPU determines that an abnormal noise is occurring and that the occupants cannot tolerate the noise, and executes abnormal noise suppression control (S150) to control the engine 22 and motors MG1 and MG2 so that the vehicle runs while the engine 22 is not stopped and continues to run at a predetermined rotational speed Neth or higher. In the abnormal noise suppression control, the same control as described above for HV driving is performed, but even when the conditions for stopping the engine 22 in HV driving are met, such as when the vehicle speed V is less than the threshold Vref1, the required torque Td* is less than the threshold Tdref, and the required power Pd* is less than the threshold Pdref, the engine 22 is not stopped and continues to run at the predetermined rotational speed Neth. The predetermined rotational speed Neth is a rotational speed predetermined as the rotational speed of the engine 22 when the engine 22 is idle (autonomous operation), and is set to, for example, 900 rpm, 1000 rpm, 1100 rpm, etc.

[0032] Here, we will explain why the engine 22 is operated at a predetermined rotational speed Neth or higher. Figure 3 is an explanatory diagram showing an example of the relationship between the rotational speed Ne of the engine 22, the vehicle speed V, and the meshing frequency of the planetary gear 30. The inventors have found that when the meshing frequency of the planetary gear 30 is in the hatched region (for example, around 2.5 kHz), when the rotational speed Ne of the engine 22 is less than the predetermined rotational speed Neth and the vehicle speed V is greater than or equal to the first speed V1, an abnormal noise occurs due to the meshing of the planetary gear 30, and this abnormal noise is caused by variations in the manufacturing precision of the tooth surface, which results in a convex shape at the tooth tip. Therefore, when the vehicle speed V is greater than or equal to the first speed V1, setting the rotational speed Ne of the engine 22 to a predetermined rotational speed Neth or higher can suppress the generation of abnormal noise due to the meshing of the planetary gear 30. For these reasons, in S150, the engine 22 is operated at a predetermined rotational speed Neth or higher. In this way, by operating the engine 22 at a predetermined rotational speed Neth or higher, abnormal noise caused by the meshing of the planetary gears 30 can be suppressed. By performing this abnormal noise suppression control when the vehicle speed V is within the range of a first speed V1 or higher and a second speed V2 or lower, and the sound pressure Sp exceeds a predetermined pressure Spth, abnormal noise that may cause discomfort to the occupants can be suppressed.

[0033] Next, the HVECU70 CPU sets flag F to value 1 (S160) and terminates this routine. This routine is executed repeatedly at predetermined intervals. Therefore, when flag F is set to value 1 in S160, the HVECU70 CPU determines that flag F is value 1 in S110 when this routine is next executed. When the HVECU70 CPU determines that flag F is value 1 in S110, it executes noise suppression control (S150) without executing S120 and S130, sets flag F to value 1 (S160), and terminates this routine. In this way, when flag F is set to value 1 (the execution of noise suppression control, which controls the engine 22 and motors MG1 and MG2 to drive while the engine 22 is not stopped during HV driving at a predetermined rotational speed of Neth or higher), the noise suppression control continues to be executed until the ignition switch 80 is turned off and the hybrid vehicle 20 system shuts down. If abnormal noise occurs due to the meshing of the planetary gear 30, the noise will continue until the planetary gear 30 is replaced or repaired. Therefore, by continuing to execute the noise suppression control until the ignition switch 80 is turned off and the hybrid vehicle 20 system shuts down, the noise can be suppressed more effectively.

[0034] According to the hybrid vehicle 20 of this embodiment described above, when the vehicle speed V is between a first speed V1 and a second speed V2, and the sound pressure Sp inside the vehicle exceeds a predetermined pressure Spth, the engine 22 and the motor MG1 are controlled to continue operating at a rotational speed of Neth or higher, thereby suppressing abnormal noises that may cause discomfort to the occupants.

[0035] In the embodiment described above, when the vehicle speed V is between the first speed V1 and the second speed V2, and the sound pressure Sp inside the vehicle exceeds a predetermined pressure Spth, the engine 22 and motor MG1 are controlled to continue operating at a rotational speed of Neth or higher. However, without considering the second speed V2, the engine 22 and motor MG1 may also be controlled to continue operating at a rotational speed of Neth or higher when the vehicle speed V is at or above the first speed V1, and the sound pressure Sp inside the vehicle exceeds a predetermined pressure Spth.

[0036] 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 motor", planetary gear 30 corresponds to "planetary gear", motor MG2 corresponds to "second motor", and engine ECU 24, motor ECU 40, and HVECU 70 correspond to "control device".

[0037] 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.

[0038] While embodiments for implementing 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]

[0039] This disclosure can be used in industries such as the hybrid vehicle manufacturing industry. [Explanation of Symbols]

[0040] 20 Hybrid vehicle, 22 Engine, 23 Crankshaft, 24 Engine electronic control unit (Engine ECU), 28 Damper, 30 Planetary gear, 36 Drive shaft, 37 Drive shaft, 38 Differential gear, 39a, 39b Drive wheels, 40 Motor electronic control unit (Motor ECU), 41, 42 Inverter, 50 Battery, 52 Battery electronic control unit (Battery ECU), 54 Power line, 80 Ignition switch, 81 Shift lever, 82 Shift position sensor, 83 Accelerator pedal, 84 Accelerator pedal position sensor, 85 Brake pedal, 86 Brake pedal position sensor, 88 Vehicle speed sensor, 90 Microphone, MG1, MG2 Motor.

Claims

1. The engine and First motor and A planetary gear is provided, in which three rotating elements are connected to the engine, the first motor, and the drive shaft connected to the axle. A second motor connected to the aforementioned drive shaft, A control device that controls the engine and the first and second motors so that the vehicle runs with intermittent operation of the engine, A hybrid vehicle equipped with, The control device controls the engine and the first motor to continue operating the engine at a rotational speed of a predetermined speed or higher when the vehicle speed is above a predetermined speed and the sound pressure inside the vehicle exceeds a predetermined pressure. Hybrid vehicle.

2. A hybrid vehicle according to claim 1, The control device controls the engine and the first motor to continue operating the engine at a rotational speed of a predetermined speed or higher when the vehicle speed is between a first speed (which is a predetermined speed) and a second speed (which is higher than the first speed), and the sound pressure inside the vehicle exceeds the predetermined pressure. Hybrid vehicle.

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