JP6958244B2 - Hybrid car - Google Patents

Description

The present invention relates to a hybrid vehicle, and more particularly to a hybrid vehicle having an engine, an automatic transmission having a torque converter with a lockup clutch, and an electric motor.

Conventionally, as a hybrid vehicle of this type, an engine, an automatic transmission having a torque converter with a lockup clutch, and an automatic transmission shaft are connected to the output shaft of the engine via a clutch and to the input shaft of the automatic transmission. A hybrid vehicle including an electric motor capable of generating power has been proposed (see, for example, Patent Document 1). When sudden braking is performed while the engine is running with the lockup clutch engaged, the lockup clutch is disengaged and the electric motor is disengaged when the lockup clutch is disengaged. By outputting the assist torque that increases the engine rotation speed from the engine, the decrease in the engine rotation speed is suppressed and the engine stall is suppressed.

Japanese Unexamined Patent Publication No. 2014-201095

In the hybrid vehicle having the above configuration, in the electric driving mode in which the engine is stopped and the vehicle travels only with the power from the motor, the rotation speed of the motor temporarily idles when the gear shift of the automatic transmission is upshifted. It may be less than the number of revolutions. In this case as well, in order to suppress the occurrence of engine stall, the lockup clutch is disengaged and the engine speed is controlled to be equal to or higher than the idle speed by the motor, but due to the loss due to the torque converter. The fuel consumption will deteriorate.

The main purpose of the hybrid vehicle of the present invention is to improve fuel efficiency.

The hybrid vehicle of the present invention has adopted the following means in order to achieve the above-mentioned main object.

The hybrid vehicle of the present invention
With the engine
An automatic derailleur with a torque converter with a lockup clutch,
An electric motor capable of generating electricity, which is connected to the output shaft of the engine via a clutch and also connected to the input shaft of the automatic transmission.
When controlling the engine, the automatic transmission, and the electric motor, the rotation speed of the electric motor is less than the idle rotation speed of the engine in the electric traveling mode in which the engine is stopped and the vehicle travels by the power from the electric motor. When this happens, a control device that executes engine stall prevention control that controls the automatic transmission so as to release the engagement by the lockup clutch, and
It is a hybrid car equipped with
In the electric traveling mode, the control device permits upshifting of the shift stage when the rotation speed of the motor when the shift stage of the automatic transmission is upshifted becomes equal to or higher than the idle speed of the engine. ,
It is characterized by that.

In the hybrid vehicle of the present invention, in the electric driving mode in which the engine is stopped and the vehicle is driven by the power from the motor, the lockup clutch is disengaged when the rotation speed of the motor becomes less than the idle rotation speed of the engine. The engine stall prevention control that controls the automatic transmission is executed. As a result, engine stall can be suppressed. Then, in the electric traveling mode, the upshift of the shift stage is permitted when the rotation speed of the motor when the shift stage of the automatic transmission is upshifted becomes equal to or higher than the idle rotation speed of the engine. As a result, the lockup clutch is not disengaged when the speed change stage of the automatic transmission is upshifted. Therefore, the rotation speed of the motor after the upshift becomes less than the idle speed of the engine, so that the lockup clutch is engaged. The loss due to the torque converter can be reduced as compared with the case where the clutch is released. As a result, fuel efficiency can be improved.

It is a block diagram which shows the outline of the structure of the hybrid vehicle 20 as an Example of this invention. It is a flowchart which shows an example of the upshift permission processing routine in electric traveling mode executed by the electronic control unit 70 of an Example. It is explanatory drawing which shows an example of the time change by the rotation speed Np of a drive shaft 46, the rotation speed Nm of a motor 30, the permission or disapproval of upshift to a shift stage (n + 1), and the difference in the shift line in the state of the shift stage.

Next, a mode for carrying out the present invention will be described with reference to examples.

FIG. 1 is a configuration diagram showing an outline of the configuration of a hybrid vehicle 20 as an embodiment of the present invention. As shown in the figure, the hybrid vehicle 20 of the embodiment includes an engine 22, a motor 30, an inverter 32, a clutch 36, an automatic transmission 40, a center differential gear 50, a high voltage battery 60, and a low voltage battery. 67, a DC / DC converter 68, and an electronic control unit 70 are provided.

The engine 22 is configured as an internal combustion engine that outputs power by using gasoline or vias as fuel. A starter motor 24 for cranking the engine 22 and an alternator 26 for generating electricity using the power from the engine 22 are connected to the crankshaft 23 as an output shaft of the engine 22.

The motor 30 is configured as, for example, a synchronous generator motor. The inverter 32 is connected to the motor 30 and is also connected to the high voltage side power line 61. The motor 30 is rotationally driven by switching control of a plurality of switching elements of the inverter 32 by the electronic control unit 70. The clutch 36 is configured as, for example, a hydraulically driven friction clutch, and connects and disconnects the crankshaft 23 as the output shaft of the engine 22 and the rotating shaft of the motor 30.

The automatic transmission 40 includes a torque converter 43, a 6-speed automatic transmission 45, and a hydraulic circuit (not shown). The torque converter 43 is configured as a general fluid type conduction device, and applies the power of the input shaft 41 connected to the rotating shaft of the motor 30 to the intermediate rotating shaft 44 which is the input shaft of the automatic transmission 45. It can be amplified and transmitted, or the torque can be transmitted as it is without being amplified. The torque converter 43 determines the rotation direction of the pump impeller attached to the input shaft 41, the turbine runner connected to the intermediate rotating shaft 44, the stator that rectifies the flow of hydraulic oil from the turbine runner to the pump impeller, and the stator. It includes a one-way clutch that limits in one direction, and a hydraulically driven lockup clutch 43a that connects the pump impeller and the turbine runner. The automatic transmission 45 is connected to an intermediate rotating shaft 44 and an output shaft 42 connected to a drive shaft 46, and includes a plurality of planetary gears and a plurality of hydraulically driven friction engaging elements (clutch, brake). , Have. The automatic transmission 45 forms forward and reverse stages from the first speed to the sixth speed by engaging and disengaging a plurality of friction engaging elements, and transmits power between the intermediate rotation shaft 44 and the output shaft 42. do.

The center differential gear 50 includes a drive shaft 46, a front transmission shaft 54 connected to the front wheels 51a and 51b via an axle 52 and a front differential gear 53, and a rear wheel 55a and 55b via an axle 56 and a rear differential gear 57. It is connected to the rear transmission shaft 58 which is connected to the rear transmission shaft 58. The center differential gear 50 distributes and transmits the power of the drive shaft 46 to the front transmission shaft 54 and the rear transmission shaft 58, and transmits the total power of the front transmission shaft 54 and the rear transmission shaft 58 to the drive shaft 46. Or something.

The high-voltage battery 60 is configured as, for example, a lithium-ion secondary battery, and is connected to the high-voltage side power line 61 together with the inverter 32. The low-voltage battery 67 is configured as, for example, a lead-acid battery having a rated voltage lower than that of the high-voltage battery 60, and is connected to the low-voltage side power line 66 together with the starter motor 24 and the alternator 26. The DC / DC converter 68 is connected to the high voltage side power line 61 and the low voltage side power line 66. The DC / DC converter 68 is controlled by the electronic control unit 70 to supply the electric power of the high voltage side electric power line 61 to the low voltage side electric power line 66 with the voltage step down.

Although not shown, the electronic control unit 70 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, and an input / output port in addition to the CPU. Signals from various sensors are input to the electronic control unit 70 via input ports. The signals input to the electronic control unit 70 include, for example, a crank angle θcr from the crank position sensor 23a that detects the rotation position of the crank shaft 23 of the engine 22, and a rotation position that detects the rotation position of the rotor of the motor 30. Examples include the rotation position θm of the rotor of the motor 30 from the detection sensor (for example, resolver) 30a, and the rotation speed Np of the drive shaft 46 from the rotation speed sensor 46a attached to the drive shaft 46. Further, the voltage Vb of the high voltage battery 60 from the voltage sensor attached between the terminals of the high voltage battery 60 and the current Ib of the high voltage battery 60 from the current sensor attached to the output terminal of the high voltage battery 60 are also mentioned. Can be done. Further, the ignition signal from the ignition switch 80, the shift position SP from the shift position sensor 82 that detects the operation position of the shift lever 81, and the accelerator opening Acc from the accelerator pedal position sensor 84 that detects the amount of depression of the accelerator pedal 83. , The brake pedal position BP from the brake pedal position sensor 86 that detects the depression amount of the brake pedal 85, and the vehicle speed V from the vehicle speed sensor 88 can also be mentioned. Various control signals are output from the electronic control unit 70 via the output port. Examples of the signal output from the electronic control unit 70 include a control signal to the engine 22, a control signal to the starter motor 24, and a control signal to the alternator 26. Further, a control signal to the inverter 32, a control signal to the clutch 36, a control signal to the automatic transmission 40, and a control signal to the DC / DC converter 68 can also be mentioned. The electronic control unit 70 calculates the rotation speed Ne of the engine 22 based on the crank angle θcr of the engine 22 from the crank position sensor 23a, and is based on the rotation position θm of the rotor of the motor 30 from the rotation position detection sensor 30a. The rotation speed Nm of the motor 30 (the rotation speed Natin of the input shaft 41 of the automatic transmission 40) is calculated.

In the hybrid vehicle 20 of the embodiment configured in this way, the electric vehicle (EV travel) mode in which the hybrid vehicle 20 travels using the power from the motor 30 with the clutch 36 off, and the engine 22 and the motor 30 with the clutch 36 on. It runs in a hybrid running (HV running) mode in which it runs using the power from the vehicle.

In the EV driving mode, the control is basically as follows. First, the target shift stage n * of the automatic transmission 40 is set based on the shift line with respect to the accelerator opening degree Acc and the vehicle speed V, and the shift stage (n) of the automatic transmission 45 is the target shift stage (n *). Sometimes the shift stage (n) is held, and when the shift stage (n) of the automatic transmission 45 is not the target shift stage (n *), the shift stage (n) is the target shift on condition that the shift is permitted. The automatic transmission 45 is controlled so as to have a gear (n *). Further, the required torque Tp * of the drive shaft 46 (output shaft 42 of the automatic transmission 40) is set based on the accelerator opening degree Acc and the vehicle speed V, and the required torque Tp * of the drive shaft 46 and the speed change of the automatic transmission 45 are set. The required torque Tin * of the input shaft 41 of the automatic transmission 40 is calculated based on the gear ratio ρ (n) of the gear (n). As the gear ratio ρ (n) of the gear ratio (n) of the automatic transmission 45, a predetermined one can be used. Then, the torque command Tm * of the motor 30 is set so that the required torque Tin * is output to the input shaft 41, and switching control of a plurality of switching elements of the inverter 32 is performed so that the motor 30 is driven by the torque command Tm *. To do.

In the HV driving mode, the control is basically as follows. The control of the automatic transmission 45 is controlled in the same manner as in the EV traveling mode. The control of the engine 22 and the motor 30 first calculates the required torque Tin * of the input shaft 41 in the same manner as in the EV driving mode, and is based on the engine 22 rotation speed Ne (= motor 30 rotation speed Nm) and the fuel efficiency operation line. The target torque Te * of the engine 22 is set, and the torque command Tm * of the motor 30 is set so that the required torque Tin * is output to the input shaft 41. Here, the fuel consumption operation line of the engine 22 is a line that defines the relationship between the power Pe, the rotation speed Ne, and the torque Te of the engine 22 that can efficiently drive the engine 22. Then, the engine 22 is controlled so that the engine 22 is operated at the target torque Te *, and the switching control of the plurality of switching elements of the inverter 32 is performed so that the motor 30 is driven by the torque command Tm *.

In the EV traveling mode and the HV traveling mode, when the rotation speed Nm of the motor 30 becomes equal to or higher than the idle rotation speed Ne (idl) of the engine 22, the lockup clutch 43a of the torque converter is engaged. Further, when the rotation speed Nm of the motor 30 becomes less than the idle speed Ne (idl) of the engine 22, the lockup clutch 43a of the torque converter 43 is disengaged. Then, the assist torque in the direction in which the rotation speed Ne of the engine 22 increases is output from the motor 30 when the lockup clutch 43a is released, and the rotation speed Ne of the engine 22 is controlled to be equal to or higher than the idle rotation speed Ne (idl). .. The reason for controlling in this way is to prevent the engine stall from occurring when the engine speed Ne becomes less than the idle speed Ne (idl).

Next, the operation of the hybrid vehicle 20 of the embodiment configured in this way, particularly the control when upshifting when traveling in the EV traveling mode will be described. FIG. 2 is a flowchart showing an example of an upshift permission processing routine in the EV traveling mode executed by the electronic control unit 70 of the embodiment. This routine is executed during EV driving.

When the EV traveling upshift permission processing routine is executed, the electronic control unit 70 first determines whether or not the state of the vehicle is at the time of acceleration (step S100). This determination can be made, for example, by determining whether or not the accelerator opening degree Acc is equal to or greater than a threshold value larger than the value 0. When it is determined that the state of the vehicle is not during acceleration, that is, when it is determined that the vehicle is braking, it is determined that it is not an upshift process because shift control (downshift control) is performed according to the regeneration control of the motor 30. And end this routine.

On the other hand, when it is determined in step S100 that the state of the vehicle is accelerating, the rotation speed Np of the drive shaft 46 from the rotation speed sensor 46a and the shift stage (n) are input (step S110), and the shift stage (step S110) is input. The rotation speed Nm (n + 1) of the motor 30 when upshifted to n + 1) is calculated (step S120). This calculation can be calculated by multiplying the rotation speed Np of the drive shaft 46 by the gear ratio ρ (n + 1) of the shift stage (n + 1).

Subsequently, it is determined whether or not the rotation speed Nm (n + 1) of the motor 30 when upshifting to the calculated shift stage (n + 1) is equal to or higher than the idle speed Ne (idl) of the engine 22 (step S130). When it is determined that the rotation speed Nm (n + 1) of the motor 30 is equal to or higher than the idle rotation speed Ne (idl), upshifting to the shift stage (n + 1) is permitted (step S140), and this routine is terminated. If the upshift is performed to the shift stage (n + 1) while this upshift is permitted, the rotation speed Nm (n + 1) of the motor 30 becomes equal to or higher than the idle speed Ne (idl) of the engine 22, so that the torque converter 43 is locked. The engagement of the up clutch 43a is retained. On the other hand, when it is determined that the rotation speed Nm (n + 1) of the motor 30 is less than the idle rotation speed Ne (idl), this routine is terminated without permitting the upshift to the shift stage (n + 1). If the engine is upshifted to the shift stage (n + 1) in this state, the rotation speed Nm (n + 1) of the motor 30 becomes less than the idle rotation speed Ne (idl) of the engine 22, and torque is used to prevent engine stall. The lockup clutch 43a of the converter 43 is disengaged, and an assist torque is output from the motor 30 so that the rotation speed Nm becomes equal to or higher than the idle rotation speed Ne (idl). However, in this routine, when the rotation speed Nm (n + 1) of the motor 30 is less than the idle speed Ne (idl), upshifting to the shift stage (n + 1) is not permitted, so that the lockup clutch 43a of the torque converter 43 The engagement is retained.

FIG. 3 is an explanatory diagram showing an example of time change due to the difference between the rotation speed Np of the drive shaft 46, the rotation speed Nm of the motor 30, the permission / rejection of upshifting to the shift stage (n + 1), and the shift line in the shift stage state. be. In the figure, the broken line at the rotation speed Np of the drive shaft 46 indicates a shift line having a large value with respect to the vehicle speed V because the accelerator opening Acc is large on the left side, and the vehicle speed V on the right side because the accelerator opening Acc is small. On the other hand, a shift line with a small value is shown. The broken line of Nm (n) at the rotation speed Nm of the motor 30 indicates the speed change stage (n) in which the rotation speed Nm (n + 1) of the motor 30 when upshifted to the speed change stage (n + 1) becomes the idle rotation speed Ne (idl). The number of rotations of the motor 30 at the time of is shown. In the case of a shift line having a large value with respect to the vehicle speed V (left side in the figure), the rotation speed Nm (n) of the motor 30 at the shift stage (n) at time T1 is upshifted to the shift stage (n + 1). Since the rotation speed Nm (n + 1) of the motor 30 becomes the idle rotation speed Ne (idl), upshifting to the shift stage (n + 1) is permitted. However, since the rotation speed Np of the drive shaft 46 does not exceed the shift line, the upshift to the shift stage (n + 1) is not performed, and the shift stage (n) is maintained. When the rotation speed Np of the drive shaft 46 exceeds the shift line at time T2, the upshift to the shift stage (n + 1) is permitted, so that the upshift to the shift stage (n + 1) is executed. In this upshift, since the rotation speed Nm of the motor 30 is larger than the idle rotation speed Ne (idl), the lockup clutch 43a of the torque converter 43 is held engaged.

In the case of a shift line having a value smaller than the vehicle speed V (right side in the figure), the rotation speed Np of the drive shaft 46 exceeds the shift line at time T3. However, when the rotation speed Nm (n) of the motor 30 at the shift stage (n) is upshifted to the shift stage (n + 1), the rotation speed Nm (n + 1) of the motor 30 is less than the idle rotation speed Ne (idl). Therefore, since the upshift to the shift gear (n + 1) is not permitted, the upshift to the shift gear (n + 1) is not performed. The rotation speed Nm (n) of the motor 30 at the shift stage (n) at the time T4 is the rotation speed Nm (n + 1) of the motor 30 when upshifting to the shift stage (n + 1), which is the idle speed Ne (idl). Therefore, the upshift to the shift gear (n + 1) is permitted, and the upshift to the shift gear (n + 1) is executed. Even in this upshift, the rotation speed Nm of the motor 30 holds the idle rotation speed Ne (idl) or more, so that the lockup clutch 43a of the torque converter 43 is kept engaged.

In the hybrid vehicle 20 of the embodiment described above, the rotation speed Nm (n + 1) of the motor 30 when upshifting to the shift stage (n + 1) during acceleration at the shift stage (n) is equal to or higher than the idle speed Ne (idl). Sometimes upshifting to gear (n + 1) is allowed. Therefore, at the time of upshifting to the shift stage (n + 1), the rotation speed Nm (n + 1) of the motor 30 becomes less than the idle rotation speed Ne (idl), and the lockup clutch 43a of the torque converter 43 is disengaged. There is nothing. Therefore, the lockup clutch 43a is disengaged, and the assist torque is output from the motor 30 so that the rotation speed Nm becomes equal to or higher than the idle rotation speed Ne (idl) (loss of the torque converter 43). It can be suppressed. As a result, fuel efficiency can be improved.

Although the embodiments for carrying out the present invention have been described above with reference to examples, the present invention is not limited to these examples, and various embodiments are used without departing from the gist of the present invention. Of course, it can be done.

The present invention can be used in the hybrid vehicle manufacturing industry and the like.

20 hybrid car, 22 engine, 23 crank shaft, 23a crank position sensor, 24 starter motor, 26 alternator, 30 motor, 30a rotation position detection sensor, 32 inverter, 36 clutch, 40 automatic transmission, 41 input shaft, 42 output shaft , 43 Torque converter, 43a lockup clutch, 44 intermediate axle, 45 automatic transmission, 46 drive shaft, 46a rpm sensor, 50 center differential gear, 51a, 51b front wheels, 52 axles, 53 front differential gear, 54 front transmission Axles, 55a, 55b rear wheels, 56 axles, 57 rear differential gears, 58 rear transmission shafts, 60 high voltage batteries, 61 high voltage side power lines, 66 low voltage side power lines, 67 low voltage batteries, 68 DC / DC converters , 70 Electronic control unit, 80 Ignition switch, 81 Shift lever, 82 Shift position sensor, 83 Axle pedal, 84 Axle pedal position sensor, 85 Brake pedal, 86 Brake pedal position sensor, 88 Vehicle speed sensor.

Claims (3)

With the engine
An automatic derailleur with a torque converter with a lockup clutch,
An electric motor capable of generating electricity, which is connected to the output shaft of the engine via a clutch and also connected to the input shaft of the automatic transmission.
When controlling the engine, the automatic transmission, and the electric motor, the rotation speed of the electric motor is less than the idle rotation speed of the engine in the electric traveling mode in which the engine is stopped and the vehicle travels by the power from the electric motor. When this happens, a control device that executes engine stall prevention control that controls the automatic transmission so as to release the engagement by the lockup clutch, and
It is a hybrid car equipped with
In the electric traveling mode, the control device sets a shift stage based on the accelerator opening degree and the vehicle speed, and the rotation speed of the electric motor when the shift stage of the automatic transmission device is upshifted is the idle rotation speed of the engine. When the number of gears exceeds the number, the upshift of the shift stage is permitted.
A hybrid car that features that. With the engine
An automatic derailleur with a torque converter with a lockup clutch,
An electric motor capable of generating electricity, which is connected to the output shaft of the engine via a clutch and also connected to the input shaft of the automatic transmission.
When controlling the engine, the automatic transmission, and the electric motor, the rotation speed of the electric motor is less than the idle rotation speed of the engine in the electric traveling mode in which the engine is stopped and the vehicle travels by the power from the electric motor. When this happens, a control device that executes engine stall prevention control that controls the automatic transmission so as to release the engagement by the lockup clutch, and
It is a hybrid car equipped with
Said control device, wherein in the electric travel mode, permits an upshift of the shift speed when the rotational speed of the motor when the gear position to upshift the automatic transmission is equal to or greater than the idle speed of the engine When the rotation speed of the motor when the shift stage of the automatic transmission is upshifted becomes less than the idle rotation speed of the engine, the upshift of the shift stage is prohibited.
A hybrid car that features that. With the engine
An automatic derailleur with a torque converter with a lockup clutch,
An electric motor capable of generating electricity, which is connected to the output shaft of the engine via a clutch and also connected to the input shaft of the automatic transmission.
When controlling the engine, the automatic transmission, and the electric motor, the rotation speed of the electric motor is less than the idle rotation speed of the engine in the electric traveling mode in which the engine is stopped and the vehicle travels by the power from the electric motor. When this happens, a control device that executes engine stall prevention control that controls the automatic transmission so as to release the engagement by the lockup clutch, and
It is a hybrid car equipped with
Said control device, wherein in the electric travel mode, permits an upshift of the shift speed when the rotational speed of the motor when the gear position to upshift the automatic transmission is equal to or greater than the idle speed of the engine When the rotation speed of the motor when the shift stage of the automatic transmission is upshifted is less than the idle rotation speed of the engine, the shift stage is held.
A hybrid car that features that.

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