JP2010089537A - Hybrid vehicle - Google Patents

Abstract

Provided is a control technique for a hybrid vehicle including a dual clutch transmission that can start an internal combustion engine without causing a driving force loss when an accelerator operation is not performed.
An ECU 100 of a hybrid vehicle 1 transmits only mechanical power output from an electric motor 50 to driving wheels 88 when the accelerator operation is not performed, and the motor driving force generated in the driving wheels 88 is used. It is possible to perform creep running that drives the vehicle. When the brake operation is being performed, the ECU 100 stops the power running of the electric motor 50 and puts all the gear stages 31, 33, and 35 of the first transmission mechanism 30 into the released state. On the other hand, when the brake operation is not performed, the electric motor 50 is powered by setting the motor driving force (creep travel driving force C) so that the vehicle speed becomes equal to or higher than a preset target vehicle speed.
[Selection] Figure 1

Description

  The present invention relates to a control technique for a hybrid vehicle including a dual clutch transmission.

  A vehicle transmission includes an output shaft of a prime mover (hereinafter referred to as an engine output shaft) and an input shaft (hereinafter referred to as a first input shaft) of a first transmission mechanism having a plurality of shift speeds (for example, odd speed stages). ) Can be engaged with the first clutch, an engine output shaft, and an input shaft (hereinafter referred to as a second input shaft) of a second transmission mechanism having a second gear stage (for example, even stages). There is known a so-called dual clutch transmission having a second clutch that can be engaged with each other. In the dual clutch transmission, the first clutch and the second clutch are alternately engaged to change the gear stage for shifting the mechanical power from the engine output shaft of the internal combustion engine. This prevents the power transmission to the drive wheels from being interrupted.

  The following Patent Document 1 discloses an automobile having a internal combustion engine and a rotating electric machine (electric motor) as a prime mover, a so-called hybrid vehicle, and a rotating electric machine connected to an input shaft of a dual clutch transmission (twin clutch automatic transmission). An automobile in which a rotor (rotor) engages is disclosed. In Patent Document 1, when the brake pedal (foot brake) is loosened and the accelerator operation amount (accelerator opening) is zero, the vehicle is driven by the torque generated in the drive wheels by powering the motor. It is proposed to perform “creep running” in which the vehicle runs at a slow speed.

JP 2007-153335 A (see page 11)

  In a hybrid vehicle equipped with a dual clutch transmission as described above, during vehicle travel in which only mechanical power output from an electric motor (rotary electric machine) is transmitted to drive wheels, so-called EV travel (hereinafter referred to as EV travel). In this case, it is necessary to start the internal combustion engine when the required driving force increases. When starting the internal combustion engine during EV traveling, one of the first clutch and the second clutch is engaged, the engine output shaft of the internal combustion engine and the drive wheel are engaged, and the torque output by the electric motor That is, by increasing the mechanical power and transmitting a part of the mechanical power to the engine output shaft, the engine output shaft can be rotationally driven. In this manner, during EV traveling of the hybrid vehicle, rotating the engine output shaft in a state where the engine output shaft of the internal combustion engine and the drive wheels are engaged is referred to as “push cranking”.

  When performing such push cranking, the rotation speed of the input shaft engaged with the engine output shaft (hereinafter referred to as cranking rotation speed) is the rotation of the drive wheel engaged with the input shaft at this time. It is proportional to the speed, that is, the vehicle speed. As the vehicle speed becomes lower, the cranking rotational speed becomes lower. In order to start the internal combustion engine, it is necessary to perform cranking so that the engine rotational speed becomes equal to or higher than a predetermined rotational speed. Therefore, when the vehicle speed is relatively low, the rotational speed of the engine output shaft engaged with the drive wheel is the rotational speed necessary for starting the internal combustion engine (hereinafter referred to as the required rotational speed) even if the push cranking is performed. The internal combustion engine may not be able to be started even if push cranking is performed.

  In such a case, of the two transmission mechanisms of the dual clutch transmission, all of the gear stages of the transmission mechanism on the side where the rotor of the electric motor and the input shaft are engaged are released, and the input shaft The engine output shaft is driven to rotate regardless of the vehicle speed by interrupting the power transmission between the engine and the drive wheel, and then engaging the clutch corresponding to the input shaft and powering the electric motor. Is possible. In this way, all the speed stages of the speed change mechanism in which the rotor of the electric motor engages with the input shaft are in the released state, and the engine output shaft is operated with the power transmission between the input shaft and the drive wheels being interrupted. The rotational driving is referred to as “normal cranking” below. However, when normal cranking is performed during vehicle travel, that is, during EV travel, power transmission between the rotor of the electric motor and the drive wheels is interrupted during that time, so mechanical power from the electric motor is There is a so-called “driving force omission” in which the driving force generated in the driving wheel is temporarily zero without being transmitted to the driving wheel.

  The present invention has been made in view of the above, and includes a dual clutch transmission that can start an internal combustion engine without causing a driving force loss when an accelerator operation is not performed. An object of the present invention is to provide a control technology for a hybrid vehicle.

  In order to achieve the above object, a hybrid vehicle according to the present invention includes an internal combustion engine and an electric motor as a prime mover, with one of a plurality of shift speeds engaged, and a first input shaft. A first speed change mechanism capable of engaging the drive wheel with the first input shaft, and engaging one of the plurality of shift speeds with the second input shaft and the drive wheel. A second transmission mechanism, a first clutch capable of engaging the engine output shaft and the first input shaft of the internal combustion engine, and the engine output shaft and the second input shaft can be engaged. A dual-clutch transmission having a second clutch and the first input shaft engaging the rotor of the electric motor, and driving only the mechanical power output from the electric motor when the accelerator operation is not performed The vehicle is driven by the motor driving force transmitted to the wheel and generated in the driving wheel. And a control means capable of performing creep driving to drive, wherein the control means stops the power running of the electric motor when the brake operation is performed, and All the speed stages of the speed change mechanism are in a released state.

  In the hybrid vehicle described above, when the brake operation is performed, the control means puts the first clutch into the engaged state and powers the electric motor to start the engine output shaft when starting the internal combustion engine. It can be driven to rotate.

  In the hybrid vehicle described above, the control means sets the motor driving force so that the electric motor is powered so that the vehicle speed is equal to or higher than a preset target vehicle speed when the brake operation is not performed. can do.

  In addition, the hybrid vehicle according to the present invention includes an internal combustion engine and an electric motor as a prime mover, and engages the first input shaft and the drive wheels with one of the plurality of shift stages engaged. A first transmission mechanism that can be operated, and a second transmission mechanism that can engage any one of the plurality of shift speeds with the second input shaft and the drive wheel engaged. A first clutch capable of engaging the engine output shaft and the first input shaft of the internal combustion engine; and a second clutch capable of engaging the engine output shaft and the second input shaft. A dual-clutch transmission in which the first input shaft engages with the rotor of the electric motor, and when the accelerator operation is not performed, only the mechanical power output from the electric motor is transmitted to the drive wheels and driven. Creep driving that drives the vehicle by the motor driving force generated in the wheels And a control means capable of performing the control, wherein the control means is configured to provide a motor so that the vehicle speed is equal to or higher than a preset target vehicle speed when the brake operation is not performed. When the driving force is set and the electric motor is caused to perform a creep running, and the brake operation is being performed, the power running of the electric motor is stopped so that the creep running is not performed, and the first speed change mechanism All the shift stages are set in a released state.

  In the hybrid vehicle described above, the internal combustion engine can be started when the rotational speed of the engine output shaft is equal to or higher than a preset required rotational speed. Engage the first speed gear, which is the forward speed having the largest reduction ratio among the speeds of the second speed change mechanism, and the clutch corresponding to the first speed of the first and second clutches. It can be assumed that the rotational speed of the engine output shaft is set to a vehicle speed that is the required rotational speed when the engine is in the state.

  According to the present invention, when the brake operation is being performed, the control means stops the power running of the electric motor and releases all the gear stages of the first transmission mechanism. When starting the engine, the engine output shaft can be rotationally driven only by engaging the first clutch and powering the electric motor. Therefore, it is possible to start the internal combustion engine by performing cranking at a desired engine rotation speed without causing a driving force dropout.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

  First, the structure of the hybrid vehicle which concerns on this embodiment is demonstrated using FIGS. 1-3. FIG. 1 is a schematic diagram showing a schematic configuration of a hybrid vehicle. FIG. 2 is a schematic diagram showing a structure of a dual clutch mechanism included in the dual clutch transmission. FIG. 3 is a schematic diagram showing the structure of a modified dual clutch mechanism.

  The hybrid vehicle 1 includes an internal combustion engine 5 and a motor generator 50 (hereinafter simply referred to as “electric motor”) that is an electric motor capable of generating electricity as a prime mover (power source) for rotationally driving the drive wheels 88. Yes. The electric motor 50 constitutes a drive device (10, 50) together with the dual clutch transmission 10. The drive device (10, 50) is coupled to the internal combustion engine 5 and mounted on the hybrid vehicle 1. The hybrid vehicle 1 includes an electronic control device (hereinafter simply referred to as “ECU”) 100 for a hybrid vehicle as control means for controlling the internal combustion engine 5, the electric motor 50, and the dual clutch transmission 10 in a coordinated manner. Is provided. The ECU 100 is provided with a ROM (not shown) as storage means for storing various control constants.

  The internal combustion engine 5 is a heat engine that converts fuel energy into mechanical power by combustion and outputs it, and is a piston reciprocating engine in which a piston 6 reciprocates in a cylinder. The internal combustion engine 5 includes a fuel injection device, an ignition device, and a throttle valve device (not shown). These devices are controlled by the ECU 100. The internal combustion engine 5 outputs the generated mechanical power from an engine output shaft (crankshaft) 8. The engine output shaft 8 is coupled to an input side of a dual clutch mechanism 20 of the dual clutch transmission 10 described later, for example, a clutch housing 14a (see FIG. 2). The ECU 100 can adjust the mechanical power output from the engine output shaft 8 of the internal combustion engine 5. The internal combustion engine 5 is provided with a crank angle sensor (not shown) that detects a rotational angle position (hereinafter referred to as a crank angle) of the engine output shaft 8, and sends a signal related to the crank angle to the ECU 100. Yes. A torque generated in the engine output shaft 8 by the operation of the internal combustion engine 5 (hereinafter referred to as engine torque) is controlled by the ECU 100.

  The electric motor 50 has a function as an electric motor that converts supplied electric power into mechanical power and outputs it, and a rotating electric machine that has a function as a generator that converts input mechanical power into electric power and recovers it. This is a so-called motor generator. The electric motor 50 is composed of a permanent magnet type AC synchronous motor, and receives a supply of three-phase AC power from an inverter 110, which will be described later, to form a rotating magnetic field, and a rotation that rotates by being attracted to the rotating magnetic field. The rotor 52 is a child, and mechanical power can be input and output from the rotor 52. The electric motor 50 is provided with a resolver (not shown) that detects the rotational angle position of the rotor 52, and sends a signal related to the rotational angle position of the rotor 52 to the ECU 100.

  The hybrid vehicle 1 is provided with an inverter 110 and a secondary battery 120 as a power supply device that supplies power to the electric motor 50. The inverter 110 is configured to convert DC power supplied from the secondary battery 120 into AC power and supply the AC power to the electric motor 50. The secondary battery 120 stores electric power supplied from the inverter 110 to the electric motor 50. The inverter 110 is also configured to be able to convert the AC power from the electric motor 50 into DC power and collect it in the secondary battery 120. The power supply from the secondary battery 120 to the electric motor 50 and the power recovery from the electric motor 50 to the secondary battery 120 are controlled by the ECU 100.

  In the following description, the fact that the electric motor 50 functions as an electric motor and the electric motor 50 outputs mechanical power from the rotor 52 is referred to as “powering”. On the other hand, the electric motor 50 is made to function as a generator, and mechanical power transmitted from the driving wheel 88 to the rotor 52 of the electric motor 50 is converted into electric power and collected in the secondary battery 120. Braking the rotation of the rotor 52 and the member (for example, the drive wheel 88) engaged with the rotor 52 by the rotational resistance generated in the rotor 52 is referred to as “regenerative braking”. Switching of functions of the electric motor 50 as an electric motor / generator and torque input or output from the rotor 52 in the electric motor 50 (hereinafter referred to as motor torque) are controlled by the ECU 100.

  The hybrid vehicle 1 is a power transmission device that transmits mechanical power from the internal combustion engine 5 and the electric motor 50 to the drive wheels 88, and changes the torque by shifting the mechanical power from the engine output shaft 8 and the electric motor 50. The dual clutch transmission 10 capable of transmitting toward the propulsion shaft 66 engaged with the drive wheel 88, and the left and right engaging with the drive wheel 88 while decelerating the mechanical power transmitted to the propulsion shaft 66. And a final reduction gear 70 that distributes to the drive shaft 80.

  The dual clutch transmission 10 engages the first input shaft 27 and the drive wheel 88 by engaging any one of the first gear stages 31, 33, and 35, and The first speed change mechanism 30 capable of shifting the mechanical power received by the first input shaft 27 by the gear speed in the engaged state and transmitting it to the drive wheels 88, and the second gear positions 42 and 44. , 46, the second input shaft 28 and the driving wheel 88 are engaged with each other, and the mechanical power received by the second input shaft 28 is brought into the engaged state. And a second speed change mechanism 40 that can change the speed at a certain speed and transmit it to the drive wheels 88. In addition, the dual clutch transmission 10 includes a first clutch 21 capable of engaging the engine output shaft 8 and the first input shaft 27 of the internal combustion engine 5, and the engine output shaft 8 and the second input shaft 28. And a dual clutch mechanism 20 constituted by a second clutch 22 that can be engaged with each other.

  The dual clutch transmission 10 has six shift stages from a first speed gear stage 31 to a sixth speed gear stage 46 for forward movement, and has one shift stage and a reverse gear stage 49 for backward movement. is doing. The reduction ratios of the first speed to the sixth speed gear stages 31 to 46 are the first speed gear stage 31, the second speed gear stage 42, the third speed gear stage 33, the fourth speed gear stage 44, and the fifth speed gear stage. 35 and the sixth gear stage 46 are set so as to decrease in order.

  The first speed change mechanism 30 is configured as a parallel shaft gear device having a plurality of gear pairs. The first group of shift speeds is an odd speed, that is, a first speed gear stage 31, a third speed gear stage 33, and the like. The fifth gear stage 35 is configured. In the first speed change mechanism 30, the first speed gear stage 31 is the speed stage on the lowest speed side (large reduction ratio) among the forward speed stages 31, 33, and 35.

  The first speed gear stage 31 is provided so as to be rotatable about a first output shaft 37 and a first speed main gear 31a coupled to the first input shaft 27, and is engaged with the first speed main gear 31a. Speed counter gear 31c. The first speed change mechanism 30 has a first speed coupling mechanism (mesh clutch mechanism) capable of engaging the first speed counter gear 31c and the first output shaft 37 corresponding to the first speed gear stage 31. , So-called dog clutch) 31e is provided. By engaging the first speed counter gear 31c and the first output shaft 37 by the first speed coupling mechanism 31e, that is, by bringing the first speed gear stage 31 into the engaged state, the first transmission mechanism 30 The mechanical power received by the input shaft 27 can be changed by the first speed gear 31 and the torque can be changed and transmitted to the first output shaft 37.

  Similarly, the third speed gear stage 33 is provided rotatably about a third speed main gear 33a coupled to the first input shaft 27 and a first output shaft 37, and the third speed main gear 33a And a third speed counter gear 33c that meshes. The first speed change mechanism 30 is provided with a third speed coupling mechanism 33e corresponding to the third speed gear stage 33 and capable of engaging the third speed counter gear 33c and the first output shaft 37. ing. By engaging the third speed counter gear 33c and the first output shaft 37 by the third speed coupling mechanism 33e, that is, by bringing the third speed gear stage 33 into the engaged state, the first transmission mechanism 30 The mechanical power received by the input shaft 27 can be shifted by the third speed gear stage 33, and the torque can be changed and transmitted to the first output shaft 37.

  The fifth speed gear stage 35 is provided so as to be rotatable about a first output shaft 37 and a fifth speed main gear 35a coupled to the first input shaft 27, and meshes with the fifth speed main gear 35a. And a fifth speed counter gear 35c. The first speed change mechanism 30 is provided with a fifth speed coupling mechanism 35e corresponding to the fifth speed gear stage 35 and capable of engaging the fifth speed counter gear 35c and the first output shaft 37. ing. By engaging the fifth speed counter gear 35c and the first output shaft 37 by the fifth speed coupling mechanism 35e, that is, by bringing the fifth speed gear stage 35 into the engaged state, the first transmission mechanism 30 The mechanical power received by the input shaft 27 can be shifted by the fifth speed gear stage 35, and the torque can be changed and transmitted to the first output shaft 37.

  A first drive gear 37 c is coupled to the first output shaft 37 of the first transmission mechanism 30, and the first drive gear 37 c meshes with the power integration gear 58. A propulsion shaft 66 is coupled to the power integration gear 58. The propulsion shaft 66 is engaged with a drive shaft 80 to which drive wheels 88 are coupled via a final reduction gear 70 described later. In other words, the first output shaft 37 on the output side of the first gear stage 31, 33, 35 of the first transmission mechanism 30 and the drive wheel 88 are engaged.

  The rotor 52 of the electric motor 50 is coupled to the first input shaft 27 of the first transmission mechanism 30, and mechanical power, that is, torque input / output from the rotor 52 is applied to the first input shaft 27 of the first transmission mechanism 30. It is transmitted as it is. That is, of the first input shaft 27 and the second input shaft 28 provided corresponding to the first transmission mechanism 30 and the second transmission mechanism 40 constituting the dual clutch transmission 10, respectively, The rotor 52 of the electric motor 50 is engaged.

  Switching between the engaged state and disengaged state (non-engaged state) of each of the gear stages 31, 33, 35 in the first transmission mechanism 30 is controlled by the ECU 100 via an actuator (not shown). The ECU 100 selects any one of the first gear stages 31, 33, and 35 of the first transmission mechanism 30 to be in an engaged state, so that the first transmission mechanism 30 is connected to the first input shaft 27. The received mechanical power can be shifted by the selected gear stage and can be transmitted from the first output shaft 37 to the drive wheels 88.

  On the other hand, like the first transmission mechanism 30, the second transmission mechanism 40 is configured as a parallel shaft gear device having a plurality of gear pairs, and the second group of shift stages is an even stage, that is, the second speed. The gear stage 42, the fourth speed gear stage 44, the sixth speed gear stage 46, and the reverse gear stage 49 are configured. In the second speed change mechanism 40, the second speed gear stage 42 is the speed stage on the lowest speed side (large reduction ratio) among the forward speed stages 42, 44, and 46.

  The second speed gear stage 42 is provided so as to be rotatable about a second output shaft 48 and a second speed main gear 42a coupled to the second input shaft 28, and engages with the second speed main gear 42a. Speed counter gear 42c. The second speed change mechanism 40 is provided with a second speed coupling mechanism 42e corresponding to the second speed gear stage 42 and capable of engaging the second speed counter gear 42c and the second output shaft 48. ing. By engaging the second speed counter gear 42c and the second output shaft 48 by the second speed coupling mechanism 42e, that is, by bringing the second speed gear stage 42 into the engaged state, the second speed change mechanism 40 is The mechanical power received by the two input shafts 28 can be shifted by the second gear stage 42, and the torque can be changed and transmitted to the second output shaft 48.

  Similarly, the fourth speed gear stage 44 is provided so as to be rotatable about a fourth speed main gear 44a coupled to the second input shaft 28 and a second output shaft 48, and is connected to the fourth speed main gear 44a. And a fourth speed counter gear 44c that meshes. The second speed change mechanism 40 is provided with a fourth speed coupling mechanism 44e corresponding to the fourth speed gear stage 44 and capable of engaging the fourth speed counter gear 44c and the second output shaft 48. ing. By engaging the fourth speed counter gear 44c and the second output shaft 48 by the fourth speed coupling mechanism 44e, that is, by bringing the fourth speed gear stage 44 into the engaged state, the second transmission mechanism 40 is The mechanical power received by the two input shafts 28 can be shifted by the fourth gear stage 44 and the torque can be changed and transmitted to the second output shaft 48.

  The sixth speed gear stage 46 is rotatably provided around a second output shaft 48 and a sixth speed main gear 46a coupled to the second input shaft 28, and meshes with the sixth speed main gear 46a. And a sixth speed counter gear 46c. The second speed change mechanism 40 is provided with a sixth speed coupling mechanism 46e corresponding to the sixth speed gear stage 46 and capable of engaging the sixth speed counter gear 46c and the second output shaft 48. ing. By engaging the sixth speed counter gear 46c and the second output shaft 48 by the sixth speed coupling mechanism 46e, that is, by bringing the sixth speed gear stage 46 into the engaged state, the second transmission mechanism 40 The mechanical power received by the two input shafts 28 can be shifted by the sixth gear stage 46, and the torque can be changed and transmitted to the second output shaft 48.

  The reverse gear stage 49 meshes with the reverse main gear 49a coupled to the second input shaft 28, the reverse intermediate gear 49b meshed with the reverse main gear 49a, and the reverse intermediate gear 49b, and is centered on the second output shaft 48. And a reverse output gear 49c provided rotatably. The second speed change mechanism 40 is provided with a reverse coupling mechanism 49e corresponding to the reverse gear stage 49 and capable of engaging the reverse output gear 49c and the second output shaft 48. The second transmission mechanism 40 is received from the second input shaft 28 by engaging the reverse output gear 49c and the second output shaft 48 by the reverse coupling mechanism 49e, that is, by bringing the reverse gear stage 49 into the engaged state. The mechanical power can be transmitted to the second output shaft 48 by changing the rotational direction to the reverse direction and changing the speed by changing the reverse gear stage 49 and changing the torque.

  A second drive gear 48 c is coupled to the second output shaft 48 of the second speed change mechanism 40, and the second drive gear 48 c meshes with the power integration gear 58. A propulsion shaft 66 is coupled to the power integrated gear 58, and the propulsion shaft 66 is engaged with a drive shaft 80 coupled to a drive wheel 88 via a final reduction gear 70 described later. In other words, the second output shaft 48 constituting the output side of the second gear stage 42, 44, 46, 49 of the second transmission mechanism 40 and the drive wheel 88 are engaged.

  Switching between the engaged state and the disengaged state (non-engaged state) of each gear stage 42, 44, 46, 49 in the second transmission mechanism 40 is controlled by the ECU 100 via an actuator (not shown). The ECU 100 selects any one of the second speed stages 42, 44, 46, and 49 of the second speed change mechanism 40 and puts it in the engaged state, so that the second speed change mechanism 40 is in the second state. The mechanical power received by the input shaft 28 can be shifted by the selected gear stage and can be transmitted from the second output shaft 48 to the drive wheels 88.

  The dual clutch mechanism 20 includes a first clutch 21 capable of engaging the engine output shaft 8 of the internal combustion engine 5 and the first input shaft 27 of the first transmission mechanism 30, and the engine output shaft 8 of the internal combustion engine 5. The second clutch 22 capable of engaging with the second input shaft 28 of the second transmission mechanism 40 is provided. The first clutch 21 and the second clutch 22 are constituted by a friction type disk clutch device such as a wet multi-plate clutch or a dry single-plate clutch.

  When the first clutch 21 is engaged, the engine output shaft 8 and the first input shaft 27 rotate together, and mechanical power from the engine output shaft 8 is transmitted to the gear stage 31 of the first transmission mechanism 30. , 33, and 35, and can be transmitted to the drive wheel 88 after being shifted. That is, the first clutch 21 is provided corresponding to the first group of gears 31, 33, 35 of the first transmission mechanism 30.

  On the other hand, by bringing the second clutch 22 into the engaged state, the engine output shaft 8 and the second input shaft 28 rotate integrally, and mechanical power from the engine output shaft 8 is shifted by the second transmission mechanism 40. The speed can be changed by any one of the stages 42, 44, 46, and 49 and transmitted to the drive wheels 88. That is, the second clutch 22 is provided corresponding to the second group of gears 42, 44, 46, 49 of the second transmission mechanism 40.

  Switching between the engaged state and the released state (non-engaged state) of the first clutch 21 and the second clutch 22 is controlled by the ECU 100 via an actuator (not shown). In the dual clutch mechanism 20, the ECU 100 sets the mechanical power from the internal combustion engine 5 to the first clutch 21 or the second clutch 22 by engaging one and releasing the other. Transmission to either one of the first transmission mechanism 30 and the second transmission mechanism 40 is possible.

  Here, an example of a detailed structure of the dual clutch mechanism 20 will be described with reference to FIG. As shown in FIG. 2, in the dual clutch mechanism 20, a clutch housing 14 a of the dual clutch mechanism 20 is coupled to the engine output shaft 8 via a damper or the like (not shown). That is, the clutch housing 14a rotates integrally with the engine output shaft 8. The clutch housing 14a is configured to accommodate friction plates (clutch disks) 27a and 28a.

  On the other hand, the first input shaft 27 of the first transmission mechanism 30 and the second input shaft 28 of the second transmission mechanism 40 are arranged coaxially and have a double shaft structure. Specifically, the second input shaft 28 is configured as a hollow shaft, and the first input shaft 27 extends into the second input shaft 28. The first input shaft 27 that is an inner shaft is configured to be longer in the axial direction than the second input shaft 28 that is an outer shaft. First, main gears 42 a, 44 a, 46 a, 49 a of each gear stage of the second transmission mechanism 40 are arranged from the engine output shaft 8 side toward the drive wheel 88 side, and then the first transmission mechanism 30. Main gears 31a, 33a, and 35a for the respective shift speeds are provided.

  A disc-shaped friction plate 27 a is coupled to the end of the first input shaft 27, while a similar friction plate 28 a is coupled to the end of the second input shaft 28. The first clutch 21 has a friction counterpart plate (not shown) provided to face the friction plate 27a, and an actuator (not shown) that drives the friction counterpart plate. The first clutch 21 engages the engine output shaft 8 and the first input shaft 27 of the first transmission mechanism 30 by the friction counterpart plate pressing the friction plate 27a against the member coupled to the clutch housing 14a. Is possible.

  Similarly, the second clutch 22 is configured such that a friction mating plate (not shown) provided opposite to the friction plate 28a presses the friction plate 28a against a member coupled to the clutch housing 14a, so that the engine output The shaft 8 can be engaged with the second input shaft 28 of the second transmission mechanism 40. In the dual clutch mechanism 20, the driving of the friction counterpart plates provided corresponding to the first and second clutches 21 and 22 by the actuator is controlled by the ECU 100.

  In the detailed structure of the dual clutch mechanism 20 described above, the first input shaft 27 of the first transmission mechanism 30 and the second input shaft 28 of the second transmission mechanism 40 are arranged coaxially. The detailed structure of the mechanism 20 is not limited to this. For example, as shown in FIG. 3, the first input shaft 27 and the second input shaft 28 may be arranged to extend in parallel with a predetermined interval. In the dual clutch mechanism 20 of this modification, a drive gear 14 c is coupled to the end of the engine output shaft 8. The first gear 16 and the second gear 18 are meshed with the drive gear 14 c, the first gear 16 is coupled to the first clutch 21, and the second gear 18 is coupled to the second clutch 22. ing. The first clutch 21 is configured to be able to engage the first input shaft 27 of the first transmission mechanism 30 and the first gear 16 that engages with the engine output shaft 8. On the other hand, the second clutch 22 is configured to be able to engage the second input shaft 28 of the second transmission mechanism 40 and the second gear 18 that engages with the engine output shaft 8.

  Each of the first and second clutches 21 and 22 can be configured by an arbitrary clutch mechanism such as a friction clutch. By alternately switching the engaged state and the released state in the first clutch 21 and the second clutch 22, the mechanical power of the internal combustion engine 5 output from the engine output shaft 8 is transferred from the drive gear 14c to the first transmission mechanism. It is transmitted to either the 30 first input shaft 27 or the second input shaft 28 of the second speed change mechanism 40.

  Further, as shown in FIG. 1, the hybrid vehicle 1 decelerates mechanical power transmitted from the prime mover to the propulsion shaft 66 and distributes it to the left and right drive shafts 80 engaged with the drive wheels 88. A device 70 is provided. The final reduction gear 70 includes a drive pinion 68 coupled to the propulsion shaft 66, and a differential mechanism 74 in which the drive pinion 68 and the ring gear 72 mesh with each other at right angles. The final reduction gear 70 decelerates the mechanical power transmitted to the propulsion shaft 66 from at least one of the prime mover, that is, the internal combustion engine 5 and the electric motor 50, by the drive pinion 68 and the ring gear 72, and the right and left by the differential mechanism 74. By distributing to the drive shaft 80 and transmitting it to the drive wheels 88 coupled to the drive shaft 80, it is possible to generate a drive force [N] for driving the hybrid vehicle 1 on the ground contact surface of the drive wheels 88. It has become.

  Further, the hybrid vehicle 1 is provided with a wheel speed sensor (not shown) that detects the rotational speed of the drive wheels 88, and sends a signal related to the detected rotational speed of the drive wheels 88 to the ECU 100. In addition, the hybrid vehicle 1 is provided with a battery monitoring unit (not shown) that detects a state-of-charge (SOC) of the secondary battery 120 that stores electric power supplied to the electric motor 50. Thus, the detected signal related to the storage state of the secondary battery 120 is sent to the ECU 100.

  Further, the hybrid vehicle 1 is provided with an accelerator pedal position sensor (not shown) that detects the amount of operation of the accelerator pedal by the driver, and relates to the amount of operation of the accelerator pedal (hereinafter referred to as accelerator operation amount). A signal is sent to the ECU 100. The hybrid vehicle 1 is also provided with a brake pedal stroke sensor (not shown) that detects the amount of operation of the brake pedal by the driver, and sends a signal related to the amount of operation of the brake pedal to the ECU 100. .

  The hybrid vehicle 1 is provided with an acceleration sensor (not shown) that can detect the longitudinal acceleration of the hybrid vehicle 1 in order to measure the gradient of the traveling road surface. It is sent to the ECU 100.

  The ECU 100 detects the engagement / release state of each shift stage in the first transmission mechanism 30 and the second transmission mechanism 40 and the engagement / release state of the first clutch 21 and the second clutch 22. The ECU 100 also includes a signal related to the rotational angle position (crank angle) of the engine output shaft 8 from a crank angle sensor (not shown), a signal related to the rotational angle position of the rotor 52 of the electric motor 50 from the resolver, A signal related to the rotational speed of the drive wheel 88 from the wheel speed sensor and a signal related to the SOC of the secondary battery 120 from the battery monitoring unit are detected.

  Based on these detection signals, the ECU 100 calculates and estimates various control variables. The control variables include the rotational speed of the engine output shaft 8 of the internal combustion engine 5 (hereinafter referred to as engine rotational speed), the torque output from the engine output shaft 8 by the internal combustion engine 5 (hereinafter referred to as engine torque), The rotational speed of the rotor 52 of the motor 50 (hereinafter referred to as motor rotational speed), the torque generated in the rotor 52 of the electric motor 50 (hereinafter referred to as motor torque), and the engagement of the first clutch 21 and the second clutch 22. / The disengaged state, the currently selected gear position in the first transmission mechanism 30 and the second transmission mechanism 40 (in the engaged state), the traveling speed of the hybrid vehicle 1 (hereinafter referred to as the vehicle speed), the secondary The SOC of the battery 120, the driving force required to be generated on the drive shaft 80 by the driver (hereinafter referred to as required driving force), and the like are included. In the following description, the current vehicle speed (current vehicle speed) is simply referred to as “vehicle speed”.

  Further, the ECU 100 detects a signal related to the accelerator operation amount from the accelerator pedal position sensor, a signal related to the brake operation amount from the brake pedal stroke sensor, and a signal related to the acceleration of the hybrid vehicle 1 from the acceleration sensor. . Based on these detection signals, the ECU 100 determines the amount of accelerator operation by the driver, the amount of brake operation by the driver, and the gradient of the traveling road surface on which the hybrid vehicle 1 is traveling (hereinafter simply referred to as “road surface gradient”). Is calculated and estimated as a control variable.

  The ECU 100 determines that the accelerator operation is not performed by the driver when the accelerator operation amount is substantially zero, that is, not more than a predetermined determination value. Further, the ECU 100 determines that the brake operation is not performed by the driver when the brake operation amount is substantially zero, that is, not more than a predetermined determination value.

  Based on these control variables, the ECU 100 grasps the operation of the internal combustion engine 5 and the electric motor 50, and the ECU 100 operates the internal combustion engine 5, that is, the engine rotation speed and the engine torque, and the operation state of the electric motor 50. That is, the motor rotation speed and the motor torque, the engagement / release state of the first clutch 21 and the second clutch 22, and the engagement / release of the gear stages 31 to 46 of the first transmission mechanism 30 and the second transmission mechanism 40. It is possible to control the state in a coordinated manner.

  In the hybrid vehicle 1 configured as described above, the mechanical power from the engine output shaft 8 of the internal combustion engine 5 is applied to the drive wheels 88 by alternately engaging the first clutch 21 and the second clutch 22. When changing the speed stage (engine output speed stage) used for power transmission to be transmitted between the speed stages 31, 33, 35 of the first speed change mechanism 30 and the speed stages 42, 44, 46 of the second speed change mechanism 40 In addition, it is possible to prevent the power transmission from the engine output shaft 8 to the drive wheels 88 from being interrupted.

  For example, when performing an upshift to switch the engine output gear stage from the first speed gear stage 31 of the first transmission mechanism 30 to the second speed gear stage 42 of the second transmission mechanism 40, the first clutch 21 is engaged. When the second clutch 22 is in the disengaged state, the second input shaft 28 is idled by previously engaging the second speed gear stage 42. An operation of switching the first clutch 21 and the second clutch 22 by bringing the second clutch 22 to be released into the engaged state while putting the first clutch 21 in the engaged state into a released state, so-called “Clutch to clutch” is performed. As a result, the power transmission path from the engine output shaft 8 to the propulsion shaft 66 is gradually moved from the first input shaft 27 of the first transmission mechanism 30 to the second input shaft 28 of the second transmission mechanism 40. The upshift from the speed gear stage 31 to the second speed gear stage 42 is completed. In this way, the dual clutch type transmission 10 does not interrupt the transmission of power from the engine output shaft 8 to the drive wheels 88, and the second speed change mechanism, that is, the speed change stage of the first speed change mechanism 30, that is, the second speed change mechanism. A shift operation for switching the engine output gear stage can be performed between 40 gear stages, i.e., even stages.

  Moreover, the hybrid vehicle 1 can implement | achieve various vehicle driving | running | working (running modes) by using together or selectively using the internal combustion engine 5 and the electric motor 50 as a motor. For example, “engine running”, which is a vehicle running in which a driving force is generated in the driving wheel 88 by transmitting only mechanical power (engine output) output from the engine output shaft 8 of the internal combustion engine 5 to the driving wheel 88; The mechanical power output from the engine output shaft 8 of the engine 5 and the mechanical power output from the rotor 52 of the electric motor 50 are integrated and transmitted to the drive wheels 88 to generate a drive force on the drive wheels 88. “HV traveling”, which is a vehicle traveling that causes the driving wheels 88 to generate a driving force by transmitting only the mechanical power output from the rotor 52 of the electric motor 50 to the driving wheels 88. Etc.

  In addition, when the hybrid vehicle 1 is allowed to perform EV travel that selectively uses only the electric motor 50 as a prime mover, the ECU 100 sets both the first clutch 21 and the second clutch 22 in a released state, and the rotor 52 of the electric motor 50. Engages one of the shift stages 31, 33, 35 of the first transmission mechanism 30 that engages with the first input shaft 27, and causes the electric motor 50 to power. The dual-clutch transmission 10 receives mechanical power (motor output) from the rotor 52 of the electric motor 50 by the first input shaft 27, and shifts at a shift stage that is engaged in the first transmission mechanism 30. Then, the power is transmitted to the drive wheel 88 via the power integration gear 58.

  In EV travel (and HV travel), mechanical power (motor output) output from the rotor 52 by the electric motor 50 is transmitted to the drive wheels 88, so that the drive force acting on the ground contact surface of the drive wheels 88 is increased. Hereinafter, it is referred to as “motor driving force”. On the other hand, by transmitting the mechanical power (engine output) output from the engine output shaft 8 by the internal combustion engine 5 to the drive wheels 88, the drive force acting on the ground contact surface of the drive wheels 88 is described below. "Engine driving force". In addition, a friction braking mechanism or the like that brakes the rotation of the drive shaft 80 and the drive wheel 88 with respect to these drive forces operates, so that the force that brakes the hybrid vehicle 1 generated on the drive wheels 88 is simply “brake brake force”. ". Further, it is a value obtained by adding the engine driving force and the brake braking force to the motor driving force, and the total driving force generated on the ground contact surface of the driving wheel 88 is hereinafter referred to as “total driving force”. When the brake braking force exceeds the motor driving force and the engine driving force, the total driving force becomes a negative value, that is, the braking force.

  In addition, the hybrid vehicle 1 causes the electric motor 50 to be powered when the accelerator operation is not performed, thereby generating a motor driving force on the driving wheels 88, so that the vehicle speed is very low (for example, 10 km / h or less). EV traveling (hereinafter referred to as “creep traveling”) can be performed. The ECU 100 determines that the accelerator operation by the driver is not performed, and the vehicle speed is equal to or lower than the predetermined vehicle speed, that is, when it is determined that the vehicle speed is low, the preset target vehicle speed is set. Then, control for adjusting the driving force (hereinafter, simply referred to as “driving force control”) is executed to power the electric motor 50. Details of the driving force control according to the present embodiment will be described later.

  Here, the driving force control according to the prior art will be described with reference to FIGS. FIG. 7A is a diagram for explaining driving force control at low vehicle speed, which is executed in a “normal hybrid vehicle” having an internal combustion engine and an electric motor as a prime mover according to the prior art. It is a figure which shows the driving force / braking force set with respect to the operation amount. FIG. 7-2 is a diagram for explaining driving force control at a low vehicle speed executed by a “normal vehicle” having only an internal combustion engine as a prime mover according to the prior art, with respect to the accelerator operation amount / brake operation amount. It is a figure which shows the driving force / braking force set.

  As shown in FIG. 7A, an “ordinary hybrid vehicle” having an internal combustion engine and an electric motor as a prime mover and capable of starting the internal combustion engine while the vehicle travels regardless of the vehicle speed is operated by an accelerator. If the accelerator operation amount is equal to or less than the set operation amount A set in advance according to the vehicle speed, only the electric motor of the prime mover is operated, and only the motor driving force is applied to the drive wheels. That is, the motor driving force becomes the total driving force generated in the driving wheels. When the accelerator operation amount exceeds the set operation amount A, the internal combustion engine is started, and the engine driving force is applied to the driving wheels in addition to the motor driving force to generate a total driving force on the driving wheels.

  When the accelerator operation is not performed and the brake operation is not performed, as shown by a point D in the figure, the motor driving force is applied to the driving wheel to perform the creep running. This motor driving force is set according to the vehicle speed, and is adjusted so as to approach the target vehicle speed during creep running. That is, as the vehicle speed increases toward the target vehicle speed, the motor driving force is controlled to be small.

  When the brake operation is performed, the motor driving force is set to decrease as the brake operation amount increases toward the determination value B set according to the vehicle speed. By setting in this way, the driver can further reduce the vehicle speed from the creep target vehicle speed by increasing the brake operation. When the amount of brake operation exceeds the above-described determination value B, a braking force is applied to the drive wheels by a friction brake mechanism (not shown).

  On the other hand, as shown in FIG. 7-2, a “normal vehicle” having only an internal combustion engine as a prime mover has an engine driving force that acts on driving wheels by operating the internal combustion engine when an accelerator operation is performed. This is the total driving force generated in the drive wheels. When the accelerator operation is not performed and when the brake operation is not performed, the engine driving force is applied to the driving wheels as shown by a point D in the figure to cause creep running. This engine driving force is preset according to the vehicle speed, and is adjusted so as to approach the target vehicle speed. When the brake operation is performed, as the amount of brake operation increases, the engine driving force is maintained at the same value, and the brake braking force is increased to reduce the total driving force generated in the drive wheels. .

  By the way, in the hybrid vehicle 1 according to the present embodiment, a request is required during EV traveling (hereinafter referred to as EV traveling) in which only the mechanical power output from the electric motor 50 is transmitted to the drive wheels 88. It is necessary to start the internal combustion engine 5 when the driving force increases. When starting the internal combustion engine 5 during EV traveling, one of the first clutch 21 and the second clutch 22 is engaged, and the engine output shaft 8 and the drive wheel 88 of the internal combustion engine 5 are engaged, The torque output from the electric motor 50, that is, mechanical power is increased, and a part of the mechanical power is transmitted to the engine output shaft 8, whereby the engine output shaft 8 can be driven to rotate. As described above, during the EV traveling of the hybrid vehicle 1, the rotational drive of the engine output shaft 8 with the engine output shaft 8 of the internal combustion engine 5 and the drive wheels 88 engaged with each other is referred to as “push-down operation”. "Ranking".

  When performing such push cranking, the rotational speed of the input shaft engaged with the engine output shaft 8 (hereinafter referred to as cranking rotational speed) is the driving wheel 88 engaged with the input shaft at this time. It is proportional to the rotational speed of the vehicle, that is, the vehicle speed. As the vehicle speed becomes lower, the cranking rotational speed becomes lower. In order to start the internal combustion engine 5, it is necessary to perform cranking so that the engine rotational speed becomes equal to or higher than a predetermined rotational speed. Therefore, when the vehicle speed is relatively low, the rotational speed (engine rotational speed) of the engine output shaft 8 that engages with the drive wheels 88 is the engine rotational speed necessary for starting the internal combustion engine 5 even if the push cranking is performed. (Hereinafter referred to as “required rotational speed”) cannot be reached, and there is a possibility that the internal combustion engine 5 cannot be started even if pushing cranking is performed.

  In such a case, of the two transmission mechanisms 30 and 40 of the dual clutch transmission 10, the gear stage of the first transmission mechanism 30 in which the rotor 52 of the electric motor 50 and the first input shaft 27 are engaged. 31, 33, 35 are all released, the power transmission between the first input shaft 27 and the drive wheel 88 is interrupted, and then the first clutch 21 corresponding to the first input shaft 27 is engaged. In addition, the engine output shaft 8 can be rotationally driven regardless of the vehicle speed by powering the electric motor 50. In this way, all the gear stages 31, 33, and 35 of the first transmission mechanism 30 in which the rotor 52 of the electric motor 50 engages with the first input shaft 27 are released, and the first input shaft 27 and the drive wheels Driving the engine output shaft 8 in a state where the power transmission to and from 88 is cut off is referred to as “normal cranking” below. However, when normal cranking is performed while the vehicle is traveling, that is, during EV traveling, power transmission between the rotor 52 of the electric motor 50 and the drive wheels 88 is interrupted during that time, so that the machine from the electric motor 50 The target power is not transmitted to the driving wheel 88, and so-called “driving force omission” occurs in which the driving force generated in the driving wheel 88 temporarily becomes zero.

  Therefore, in the hybrid vehicle 1 including the dual clutch transmission 10 according to the present embodiment, the driving is performed when the accelerator operation is not performed and the vehicle speed is low such that creep driving is performed in the related art. There is a demand for a control technique that can reliably start the internal combustion engine 5 without causing power loss.

  Therefore, in the hybrid vehicle 1 according to the present invention, the ECU 100 as the control means causes the driving force to be lost by executing the driving force control described below when the accelerator operation is not performed at the low vehicle speed. The internal combustion engine 5 can be started without any problem, and will be described below with reference to FIGS. 1 and 4 to 6. FIG. 4 is a diagram for explaining the driving force control at a low vehicle speed executed by the control means (ECU) of the hybrid vehicle according to the present embodiment. The driving force / set to the accelerator operation amount / brake operation amount / It is a figure which shows braking force. FIG. 5 is a schematic diagram for explaining a setting method of a creep driving force that is a motor driving force when creep driving is performed. FIG. 6 is a diagram illustrating an acceleration target driving force map used for setting the creep travel driving force, and is a diagram illustrating the driving force / braking force set for the vehicle speed.

  As shown in FIGS. 1 and 4, the ECU 100 sets the driving force / braking force according to the vehicle speed of the hybrid vehicle 1 and the accelerator operation amount / brake operation amount. Specifically, the total driving force (that is, the motor driving force and the engine driving force) and the brake braking force are set. The ECU 100 determines the motor torque output by the electric motor 50, in other words, the motor output, in accordance with the vehicle speed, the motor driving force, and the gear position engaged in the first transmission mechanism 30. Let it run.

  As shown in FIG. 4, when the accelerator operation is performed and the accelerator operation amount exceeds a preset determination operation amount A, the ECU 100 causes the drive wheel 88 when the EV travel is performed. Therefore, it is determined that the required total driving force (required driving force) cannot be realized, the internal combustion engine 5 is started, and the engine output is transmitted to the drive wheels 88. As a result, the engine driving force is applied to the driving wheel 88, and the required driving force (total driving force) is achieved together with the motor driving force that similarly applies to the driving wheel 88. On the other hand, when the accelerator operation is performed and the accelerator operation amount is equal to or less than the determination operation amount A, the ECU 100 determines that the total driving force (required driving force) can be achieved by the motor driving force, Let the EV run.

  When the accelerator operation is not performed and the brake operation is not performed (OFF), the ECU 100 determines the motor driving force according to the road gradient and the vehicle speed so that the vehicle speed is equal to or higher than a preset target vehicle speed. The hybrid vehicle 1 is caused to perform creep running by causing the electric motor 50 to power-run so that the driving force is generated in the driving wheels 88 with the “creep running driving force” set as described above.

  The target vehicle speed includes the first speed gear stage 31 that is the forward speed stage having the largest reduction ratio among the speed stages 31 to 49 of the first and second speed change mechanisms 30 and 40, and the first and second clutches 21. , 22 when the first clutch 21 corresponding to the first speed gear stage 31 is engaged, the engine rotational speed is a required rotational speed that is an engine rotational speed necessary for starting the internal combustion engine 5; It is set to be. That is, the target vehicle speed is set to a vehicle speed at which the internal combustion engine 5 can be started by performing “push cranking”.

On the other hand, as shown in FIG. 5, the creep driving force is set based on the target vehicle speed set as described above, the road surface gradient θ, and the current vehicle speed. As indicated by reference numeral FF1 in FIG. 5, the ECU 100 calculates the “gradient resistance”, which is a running resistance caused by the road surface gradient θ, from the mass M of the hybrid vehicle 1, the gravitational acceleration g, and the road surface gradient (tilt angle) θ: This is estimated by the equation (1).
(Gradient resistance) = M · g · sin θ (1)
Then, the estimated gradient resistance is multiplied by an FF (feed forward) gain. The FF gain is set to a constant lower than 1.0, such as 0.9. This is to prevent the creep driving force C from becoming larger than expected even when the estimation accuracy of the road surface gradient is not good.

  Further, as indicated by reference numeral FF2, the ECU 100 determines the driving force / braking force to be generated on the driving wheels 88 with respect to the current vehicle speed in order to accelerate / decelerate the hybrid vehicle 1 toward the target vehicle speed. Is estimated using the acceleration target driving force map shown in FIG. As shown in the figure, the acceleration target driving force map is set so that the driving force decreases as the vehicle speed approaches the target vehicle speed from the low speed side. When the vehicle speed matches the target vehicle speed, the driving force is zero. Is set to If the vehicle speed exceeds the target vehicle speed, the braking force is set instead of the driving force according to the acceleration target driving force map, and the braking force is set to increase as the vehicle speed moves away from the target vehicle speed to the high speed side. ing.

  Thus, the ECU 100 estimates the driving force / braking force based on the current vehicle speed so as to accelerate and decelerate the hybrid vehicle 1 toward the target vehicle speed, and the feedforward control FF1 that estimates the gradient resistance based on the road surface gradient. The feed forward control FF2 is executed to set the creep driving force. In addition, the ECU 100 estimates the correction value of the creep travel driving force by performing PID control (feedback control) based on the target vehicle speed and the current vehicle speed, as indicated by reference numeral FB in FIG. As described above, the ECU 100 sets the creep travel driving force C based on the target vehicle speed, the road surface gradient θ, and the current vehicle speed.

  As described above, by causing the hybrid vehicle 1 to perform creep travel (EV travel) so that the vehicle speed becomes equal to or higher than the above-described target vehicle speed, the first speed gear stage 31 is used when starting the internal combustion engine 5 during the creep travel. By engaging the first clutch 21 corresponding to the above and engaging the engine output shaft 8 and the drive wheel 88, the engine rotation speed is made higher than the necessary rotation speed necessary for starting the internal combustion engine 5. The internal combustion engine 5 can be started by performing “push cranking”. In this way, when the accelerator operation is not performed and the brake operation is not performed, the necessary rotation can be performed without causing a driving force loss during the creep traveling by performing the creep traveling at a speed higher than the target vehicle speed. The internal combustion engine 5 can be reliably started by cranking at a speed higher than that.

  On the other hand, as shown in FIG. 4, when the accelerator operation is not performed and the brake operation is performed, the ECU 100 stops the power running of the electric motor 50 to reduce the motor driving force to zero, The brake braking force is set to a larger value as the brake operation amount increases, and the vehicle speed is set to zero. That is, when the brake operation is performed, the hybrid vehicle 1 is stopped without performing EV traveling (creep traveling).

  Thus, by setting the motor driving force to zero, the ECU 100 can prepare for starting the internal combustion engine 5 by releasing all the gear stages 31, 33, and 35 of the first transmission mechanism 30. Specifically, when the internal combustion engine 5 is started, the first clutch 21 is engaged and the electric motor 50 is powered to prepare for “normal cranking” in which the engine output shaft 8 is driven to rotate. it can. Thus, when the accelerator operation is not performed and the brake operation is performed, the power running of the electric motor 50 is stopped, the hybrid vehicle 1 is stopped, and normal cranking is performed. The internal combustion engine 5 can be started by cranking at a desired engine rotational speed without causing a drive force loss.

[Starting control]
Further, in the present embodiment, the ECU 100 determines whether or not to start the internal combustion engine 5 depending on whether the secondary battery 120 is in the storage state (SOC), the current vehicle speed, and whether or not the brake operation is being performed ( Hereinafter, the starting condition is determined), and details will be described below.

  When the SOC of the secondary battery 120 falls below the first determination value Sa, the ECU 100 immediately starts the internal combustion engine 5 regardless of the current vehicle speed and the presence or absence of a brake operation. When starting the internal combustion engine 5, if the vehicle speed is equal to or higher than the target vehicle speed, the internal combustion engine 5 is started by performing the “push cranking” described above. On the other hand, when the vehicle speed is lower than the target vehicle speed, the “normal cranking” is performed to start the internal combustion engine 5. The electric motor 50 is operated as a generator, a part of mechanical power (engine output) output from the internal combustion engine 5 is transmitted to the rotor 52 and converted into electric power by the electric motor 50, and the secondary battery 120. To increase the SOC. Even when the vehicle speed is lower than the target vehicle speed, the internal combustion engine 5 is started and the SOC of the secondary battery 120 is increased even if “normal cranking” is immediately performed and “driving force loss” occurs.

  In addition, when the SOC of the secondary battery 120 is lower than the second determination value Sb set to a value higher than the first determination value Sa and the current vehicle speed is equal to or higher than the above-described target vehicle speed, the ECU 100 Then, “push cranking” is performed to start the internal combustion engine 5. That is, when the SOC of the secondary battery 120 is equal to or higher than the first determination value Sa and lower than the second determination value Sb, the ECU 100 determines that “push cranking” is performed when the vehicle speed is equal to or higher than the target vehicle speed. To start the internal combustion engine 5. As a result, the internal combustion engine 5 can be started without causing “driving force loss”.

  In addition, the ECU 100 determines that the SOC of the secondary battery 120 is lower than the third determination value Sc set to a value higher than the second determination value Sb, the vehicle speed is lower than the target vehicle speed, and a brake operation is performed. If so, “normal cranking” is performed and the internal combustion engine 5 is started. Since the brake operation is performed, the motor driving force is zero by the driving force control described above. That is, no torque acts between the first input shaft 27 of the first transmission mechanism 30 and the drive wheels 88 and the first output shaft 37. In this state, all of the gear stages 31, 33, 35 of the first transmission mechanism 30 are released, the first clutch 21 is engaged, and the electric motor 50 is powered to perform “normal cranking”. It can be carried out. In this case, even if the “normal cranking” is performed, the driving force generated in the driving wheel 88, that is, the motor driving force is zero in the first place, so that the internal combustion engine 5 can be started without causing “driving force omission”. Can do.

  The ECU 100 starts the internal combustion engine 5 in accordance with the start conditions as described above, and operates the electric motor 50 as a generator to suppress the SOC of the secondary battery 120 from falling below the first determination value Sa as much as possible. can do. In other words, when the internal combustion engine 5 is started by performing “normal cranking” under the starting condition in which the SOC of the secondary battery 120 is lower than the first determination value Sa and the vehicle speed is lower than the target vehicle speed. The occurrence of “driving force loss” is suppressed.

  As described above, the hybrid vehicle 1 according to the present embodiment has the internal combustion engine 5 and the electric motor 50 as a prime mover, and puts one of the plurality of shift stages 31, 33, 35 into an engaged state. Thus, the first transmission mechanism 30 capable of engaging the first input shaft 27 and the drive wheels 88 and any one of the plurality of shift stages 42, 44, 46, 49 are engaged. The second speed change mechanism 40 capable of engaging the second input shaft 28 and the drive wheel 88, and the second speed change mechanism 40 capable of engaging the engine output shaft 8 of the internal combustion engine 5 and the first input shaft 27. 1 clutch 21 and second clutch 22 capable of engaging engine output shaft 8 and second input shaft 28, and first input shaft 27 engages with rotor 52 of electric motor 50. Dual clutch transmission 10 and accelerator operation is not performed ECU 100 as a control means capable of transmitting only the mechanical power output from the electric motor 50 to the drive wheels 88 and driving the vehicle with the motor drive force generated in the drive wheels 88. It has.

  When the brake operation is being performed, the ECU 100 stops the power running of the electric motor 50 so that the motor driving force is zero, and all the gear stages 31, 33, and 35 of the first transmission mechanism 30 are released. Therefore, when the internal combustion engine 5 is started, the engine output shaft 8 can be rotationally driven only by bringing the first clutch 21 into the engaged state and powering the electric motor 50. It is possible to start the internal combustion engine 5 by performing cranking at a desired engine rotational speed without causing a driving force dropout.

  In the present embodiment, when the brake operation is performed, the ECU 100 puts the first clutch 21 into the engaged state and powers the electric motor 50 to start the engine when starting the internal combustion engine 5. Since “normal cranking” for rotationally driving the output shaft 8 is performed, it is possible to start the internal combustion engine 5 by performing cranking at a desired engine rotational speed without causing drive force loss.

  In the present embodiment, the ECU 100 sets the motor driving force (creep travel driving force C) so that the vehicle speed is equal to or higher than a preset target vehicle speed when the brake operation is not performed. The electric motor 50 was to be powered. The target vehicle speed is set to a vehicle speed at which the rotational speed (engine rotational speed) of the engine output shaft 8 becomes a necessary rotational speed necessary for starting the internal combustion engine 5 when the engine output shaft 8 and the drive wheels 88 are engaged. Thus, when the internal combustion engine 5 is started during the creep travel, the first clutch 21 corresponding to the first gear 31 is engaged, and the engine output shaft 8 and the drive wheel 88 are connected. By engaging, the engine rotational speed can be made higher than the required rotational speed, and the internal combustion engine 5 can be started by performing “push cranking”. During creep travel, the internal combustion engine 5 can be reliably started by performing cranking at a speed higher than the required rotational speed without causing a loss of driving force.

  Further, in the hybrid vehicle 1 according to the present embodiment, the ECU 100 as the control unit sets the motor driving force so that the vehicle speed is equal to or higher than a preset target vehicle speed when the brake operation is not performed. Then, the electric motor 50 is caused to power-run to perform creep travel, and when the brake operation is performed, the power running of the electric motor 50 is stopped and the motor driving force is set to zero so that the creep travel is not performed. The gears 31, 33, and 35 of the first transmission mechanism 30 are all set to the released state. When the brake operation is not performed, when the engine output shaft 8 and the drive wheel 88 are engaged, the engine rotational speed of the internal combustion engine 5 is set in advance so as to be equal to or higher than the necessary rotational speed necessary for starting. By performing creep travel at a speed higher than the target vehicle speed, the internal combustion engine 5 can be started by performing “push cranking”. The ranking is performed and the internal combustion engine 5 can be started reliably. On the other hand, when the brake operation is performed, when the internal combustion engine 5 is started, the “normal cranking” is performed, and the internal combustion engine 5 can be started without causing a driving force loss.

  In the present embodiment, the internal combustion engine 5 can be started when the rotational speed of the engine output shaft 8 is equal to or higher than a preset required rotational speed, and the target vehicle speed is: Of the first and second speed change mechanisms 30 and 40, the first speed gear 31 that is the forward gear having the largest reduction ratio among the gears 31 to 49, and the first and second clutches 21 and 22 Since the rotational speed of the engine output shaft 8 is set to the vehicle speed that is the required rotational speed when the clutch corresponding to the first speed gear stage 31 is engaged, the engine speed of the internal combustion engine 5 The target vehicle speed at which the speed reaches the required rotational speed can be made as low as possible.

  In the present embodiment, the shift stages 31, 33, and 35 of the first transmission mechanism 30, which is a transmission mechanism in which the rotor 52 of the electric motor 50 is engaged with the input shaft (first input shaft 27), are odd-numbered stages (first stage). 1st gear stage, 3rd speed gear stage, and 5th gear stage), but the aspect of the dual clutch transmission to which the present invention is applicable is not limited to this. . The shift stage of the second speed change mechanism in which the input shaft is not engaged with the rotor of the electric motor is constituted by an odd number of stages, while the speed change stage of the first speed change mechanism in which the input shaft is engaged with the rotor of the electric motor. However, it may be composed of an even number of stages.

  In the present embodiment, the electric motor 50 has a function as an electric motor that converts the supplied electric power into mechanical power and outputs the electric power, and a function as a generator that converts the input mechanical power into electric power. Although the motor generator is also provided, the electric motor according to the present invention is not limited to this. The electric motor 50 may be configured by an electric motor having only a function of converting electric power supplied from the secondary battery 120 into mechanical power and outputting it from the rotor 52.

  Further, in the forward shift stages 31 to 46 of the first and second transmission mechanisms 30 and 40 according to the present embodiment, the main gears 31 a to 46 a are respectively coupled to the first input shaft 27 or the second input shaft 28. The counter gears 31c to 46c that mesh with the main gears 31a to 46a, respectively, are rotatably provided around the first output shaft 37 or the second output shaft 48, and are coupled to a coupling mechanism (meshing clutch mechanism, so-called so-called clutch mechanism). The dog clutches 31e to 46e engage the counter gears 31c to 46c and the output shafts 37 and 48 corresponding to the counter gears 31c to 46c, but the mode of the coupling mechanism is not limited thereto. In at least some of the gears of the first and second speed change mechanisms, the main gear is provided rotatably about the input shaft corresponding thereto, and the counter gear is the output shaft corresponding thereto. The coupling mechanism may engage the main gear and the input shaft.

  In the present embodiment, the rotor 52 of the electric motor 50 is coupled to the first input shaft 27 of the first transmission mechanism 30. However, a mode of a dual clutch transmission to which the present invention can be applied. However, the present invention is not limited to this. The first input shaft only needs to be engaged with the rotor of the electric motor. For example, a reduction mechanism that reduces the rotational speed of the rotor and transmits it to the first input shaft 27 between the first input shaft and the rotor. Alternatively, a speed change mechanism that changes the rotational speed of the rotor and transmits it to the first input shaft 27 may be provided.

  Further, in the present embodiment, the dual clutch transmission 10 includes power integration in which the first transmission mechanism 30 engages mechanical power received by the first input shaft 27 with the drive wheels 88 from the first output shaft 37. The mechanical power transmitted to the gear 58 and received by the second transmission mechanism 40 at the second input shaft 28 is transmitted from the second output shaft 48 to the power integrated gear 58. The mode of power transmission from the two speed change mechanism to the drive wheels is not limited to this. The first transmission mechanism and the second transmission mechanism only need to be able to transmit the mechanical power received by the input shaft to the drive wheels. For example, the first transmission mechanism and the second transmission mechanism are respectively the first transmission mechanism and the second transmission mechanism. Mechanical power received by the input shaft and the second input shaft may be transmitted to a common output shaft engaged with the drive wheels.

  In the present embodiment, the dual clutch transmission 10 transmits mechanical power from the engine output shaft 8 of the internal combustion engine 5 and the rotor 52 of the electric motor 50 to the first transmission mechanism 30 and the second transmission mechanism 40. The speed is changed by at least one and transmitted from the power integrated gear 58 to the drive wheel 88 via the propulsion shaft 66 and the differential mechanism 74 of the final reduction gear 70, but from the first speed change mechanism and the second speed change mechanism. The mode of power transmission toward the drive wheels is not limited to this. In the dual clutch transmission, the first speed change mechanism and the second speed change mechanism need only be able to transmit the mechanical power received by the first input shaft and the second input shaft to the drive wheels 88, respectively. The power integrated gear or the drive gear meshing with the power integrated gear may directly drive the ring gear of the differential mechanism.

  As described above, the present invention is useful for a hybrid vehicle including a dual clutch type transmission.

It is a mimetic diagram showing a schematic structure of a hybrid vehicle concerning this embodiment. It is a schematic diagram which shows the structure of the dual clutch mechanism which concerns on this embodiment. It is a schematic diagram which shows the structure of the dual clutch mechanism of the modification which concerns on this embodiment. It is a figure explaining the driving force control at the time of the low vehicle speed which the control means (ECU) of the hybrid vehicle which concerns on this embodiment shows, and shows the driving force / braking force set with respect to an accelerator operation amount / brake operation amount FIG. It is a schematic diagram explaining the setting method of the creep driving force which is a motor driving force when performing creep driving. It is a figure explaining the driving force map for acceleration target used for the setting of creep driving force, and is a figure which shows the driving force / braking force set with respect to a vehicle speed. It is a figure explaining the driving force control at the time of the low vehicle speed performed in the "normal hybrid vehicle" provided with the internal combustion engine and the electric motor as a prime mover according to the prior art, and is set with respect to the accelerator operation amount / brake operation amount It is a figure which shows the driving force / braking force performed. It is a figure explaining the driving force control at the time of the low vehicle speed which the "normal vehicle" provided only with the internal combustion engine as a motor | power_engine which concerns on a prior art, and is set with respect to the driving force / accelerator operating amount / brake operating amount It is a figure which shows braking force.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hybrid vehicle 5 Internal combustion engine 8 Engine output shaft 10 Dual clutch transmission 20 Dual clutch mechanism 21 First clutch 22 Second clutch 27 First input shaft 28 Second input shaft 30 First transmission mechanism 31, 33, 35 Gear stage (Gear, gear pair)
37 1st output shaft 40 2nd speed change mechanism 42, 44, 46, 49 Gear stage (gear stage, gear pair)
48 Second output shaft 50 Electric motor (motor generator)
52 Electric Motor Rotor 66 Propulsion Shaft 70 Final Deceleration Device 74 Differential Mechanism 80 Drive Shaft 88 Drive Wheel 100 Electronic Control Device for Hybrid Vehicle (ECU, Control Means, Storage Means)

Claims (5)

It has an internal combustion engine and an electric motor as a prime mover,
A first transmission mechanism capable of engaging any one of the plurality of shift speeds to engage the first input shaft and the drive wheel; and any one of the plurality of shift speeds. A first speed change mechanism capable of engaging the second input shaft and the drive wheel in an engaged state, and a first speed change mechanism capable of engaging the engine output shaft of the internal combustion engine and the first input shaft. A dual clutch transmission having a clutch and a second clutch capable of engaging the engine output shaft and the second input shaft, wherein the first input shaft is engaged with the rotor of the electric motor;
Control capable of transmitting only the mechanical power output from the electric motor to the drive wheels when the accelerator operation is not being performed and causing the vehicle to drive the vehicle with the motor driving force generated in the drive wheels. Means,
A hybrid vehicle with
The control means
If the brake is being operated,
A hybrid vehicle characterized in that the power running of the electric motor is stopped and all the gear positions of the first transmission mechanism are released. The hybrid vehicle according to claim 1,
The control means
If the brake is being operated,
A hybrid vehicle characterized in that when the internal combustion engine is started, the first clutch is engaged and the electric motor is driven to rotate the engine output shaft. In the hybrid vehicle according to claim 1 or 2,
The control means
If the brake is not operated,
A hybrid vehicle characterized in that an electric motor is powered by setting a motor driving force so that a vehicle speed is equal to or higher than a preset target vehicle speed. It has an internal combustion engine and an electric motor as a prime mover,
A first transmission mechanism capable of engaging any one of the plurality of shift speeds to engage the first input shaft and the drive wheel; and any one of the plurality of shift speeds. A first speed change mechanism capable of engaging the second input shaft and the drive wheel in an engaged state, and a first speed change mechanism capable of engaging the engine output shaft of the internal combustion engine and the first input shaft. A dual clutch transmission having a clutch and a second clutch capable of engaging the engine output shaft and the second input shaft, wherein the first input shaft is engaged with the rotor of the electric motor;
Control capable of transmitting only the mechanical power output from the electric motor to the drive wheels when the accelerator operation is not being performed and causing the vehicle to drive the vehicle with the motor driving force generated in the drive wheels. Means,
A hybrid vehicle with
The control means
If the brake is not operated,
The motor driving force is set so that the vehicle speed is equal to or higher than a preset target vehicle speed, the electric motor is powered, and creep running is performed.
If the brake is being operated,
A hybrid vehicle characterized in that the power running of the electric motor is stopped so that creep travel is not performed, and all the gear positions of the first transmission mechanism are released. In the hybrid vehicle according to claim 3 or 4,
The internal combustion engine is capable of starting when the rotational speed of the engine output shaft is equal to or higher than a preset required rotational speed,
The target vehicle speed includes a first speed gear stage that is the forward speed stage having the largest reduction ratio among the speed stages of the first and second speed change mechanisms, and the first speed gear stage of the first and second clutches. A hybrid vehicle characterized in that when the clutch corresponding to is engaged, the rotational speed of the engine output shaft is set to a required vehicle speed.

Images