JP2015189279A - Flywheel type regeneration system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the rotational speed difference of a friction fastening element provided between a flywheel and a power transmission system of a vehicle when fastening the friction fastening element in a flywheel type regeneration system.SOLUTION: The flywheel type regeneration system comprises: a transmission 3 which is mounted in a vehicle 100 and in which an input part 31 is connected to a driving source 1 and an output part 32 is connected to a driving wheel 6; a flywheel 2; a friction fastening element 92 in which a first element 92a connected to the transmission 3 and a second element 92b connected to the flywheel 2 are fastened together and released from each other; a motor 20 connected to the flywheel 2; and control means 8 performing regeneration control for fastening the friction fastening element 92 upon braking of the vehicle, and thereby regenerating rotational energy of a vehicle driving system into rotational energy of the flywheel 2. When fastening the friction fastening element 92, the control means 8 controls the motor 20 so as to reduce the rotational speed difference between the first element 92a and the second element 92b of the friction fastening element 92 in advance.

Description

  The present invention relates to a flywheel regenerative system capable of performing mechanical regeneration in which kinetic energy during deceleration of a vehicle is converted into rotational energy of a flywheel for regeneration.

  Regenerative technology that regenerates and stores rotational energy of the drive shaft during braking of the vehicle and then reuses the stored energy as rotational energy of the drive shaft, that is, kinetic energy for running the vehicle, to increase energy efficiency. Has been developed. The energy regeneration in this case includes electrical regeneration that converts the rotational energy of the drive shaft into electrical energy and regenerates the battery, and mechanical regeneration that converts the rotational energy of the drive shaft into rotational energy of the flywheel and regenerates it. There is.

  In both cases of electrical regeneration and mechanical regeneration, energy loss occurs when converting the rotational energy of the drive shaft into each energy, and the drive loss is greater than energy loss when converting the rotational energy of the drive shaft into electrical energy. The energy loss when converting the rotational energy of the shaft into the rotational energy of the flywheel is smaller. Further, the rotational energy of the flywheel has a characteristic that it gradually attenuates with time due to friction loss and the like.

  Therefore, when converting the rotational energy of the drive shaft into the rotational energy of the flywheel, if the rotational energy of the flywheel is immediately converted into the kinetic energy of the vehicle, the total energy loss is less than when converting into electrical energy. However, if it takes longer time to convert the rotational energy of the flywheel to the kinetic energy of the vehicle, the total energy loss becomes larger than that of the electrical energy.

  Therefore, for example, Patent Document 1 predicts whether or not the energy attenuation loss due to the attenuation of the rotational energy of the flywheel exceeds the allowable range, and when the energy attenuation loss is predicted to exceed the allowable range, the flywheel A technology has been proposed in which the rotational energy of the flywheel is transmitted to the motor generator, whereby the rotational energy of the flywheel is converted into electric energy by the motor generator and regenerated to the battery.

JP 2011-038621 A

  By the way, the flywheel is required to be connected to the vehicle power transmission system at the time of regenerating rotational energy or to reuse the stored energy thereafter, and to be disconnected from the vehicle power transmission system at other times. Therefore, a clutch (friction engagement element) for connecting / disconnecting power is interposed between the flywheel and the power transmission system of the vehicle, and this clutch is engaged at the time of energy regeneration or energy reuse, and is released at other times. I am doing so.

  Here, when the clutch is engaged, if there is a difference in rotational speed between the frictional engagement elements to be engaged, heat is generated at the time of engagement, resulting in energy loss. It is effective to plan. For this purpose, the rotational speed difference of the frictional engagement element may be reduced, but how to reduce the rotational speed difference of the frictional engagement element is an important issue.

  The present invention has been devised in view of such a problem, and reduces the difference in rotational speed of the frictional engagement element when fastening the frictional engagement element provided between the flywheel and the power transmission system of the vehicle. The purpose of this is to provide a flywheel regenerative system.

  (1) In order to achieve the above object, a flywheel regeneration system according to the present invention is equipped with a transmission, an input unit connected to a drive source, and an output unit connected to a drive wheel. And a friction engagement element having a first element and a second element that are fastened and released to each other, wherein the first element is connected to the input portion of the transmission, and the second element is connected to the flywheel. A motor connected to the flywheel; and a control means for performing regenerative control for regenerating rotational energy of the drive system of the vehicle to rotational energy of the flywheel by fastening the friction engagement element during braking of the vehicle. The control means controls the motor before fastening the frictional engagement element to reduce the rotational speed difference between the first element and the second element of the frictional engagement element. It is characterized by carrying out the difference control.

  (2) The rotational speed difference control is a rotational speed difference increase suppression control that controls the motor to suppress an increase in the rotational speed difference of the frictional engagement element accompanying a decrease in the rotational speed of the flywheel. Is preferred.

  (3) In this case, the control means sets a target rotational speed of the flywheel according to the vehicle speed of the vehicle, and a control start condition including that the rotational speed of the flywheel is lower than the target rotational speed is established. Then, it is preferable to start the rotation speed difference increase suppression control.

  (4) The transmission is a continuously variable transmission, and the control means controls a transmission ratio of the transmission using a shift line corresponding to an accelerator pedal opening, and the target rotational speed is It is preferable that the rotational speed corresponding to the rotational speed of the input unit determined according to the vehicle speed is set according to the shift line when the accelerator pedal is fully closed.

  (5) Furthermore, an oil pump that is driven by the rotation of the input portion of the transmission and generates a hydraulic pressure for shifting the transmission is provided, and a discharge flow rate of the oil pump necessary for controlling the transmission is set. Rotation corresponding to the rotation speed of the input unit determined according to the vehicle speed according to the shift line when the accelerator pedal is fully closed, with respect to the rotation amount ensuring the oil amount balance that is the lower limit value of the rotation speed of the input unit that can be secured When the speed is lower, the target rotation speed is preferably set to the oil amount balance ensuring rotation speed.

  (6) It is preferable that the control start condition includes that the vehicle is traveling with a driving force of the driving source and that the vehicle speed is equal to or lower than an upper limit vehicle speed.

  (7) Further, the control start condition is that the rotational speed of the flywheel is less than the target rotational speed, and the rotational speed of the flywheel is equal to or higher than a lower limit rotational speed set according to the vehicle speed. It is preferable that it is included.

  (8) It is preferable that the control unit includes a prediction unit that predicts deceleration traveling of the vehicle, and that the control start condition includes that the prediction unit predicts deceleration traveling.

  (9) The rotational speed difference control is configured such that, during braking of the vehicle, when a control start condition including that the rotational speed of the flywheel falls below the target rotational speed is satisfied, the motor is controlled and the friction engagement is performed. It is preferable that the pre-engagement control is performed to reduce the rotational speed difference of the friction engagement element before starting the element engagement.

  (10) Preferably, the control means performs the pre-engagement control so that the rotational speed difference of the frictional engagement element becomes zero.

  (11) It is preferable that the control means is engaged while slipping the friction engagement element after reducing the rotational speed difference by the pre-engagement control.

  (12) The transmission is a continuously variable transmission, and the control means controls a transmission ratio of the transmission using a shift line corresponding to an accelerator pedal opening, and the regenerative control start condition includes In addition to the fact that the vehicle is in a braking state, it is included that the rotational speed of the input portion of the transmission is a rotational speed according to a shift line when the accelerator pedal is fully closed. preferable.

  According to the flywheel type regeneration system of the present invention, the frictional engagement element is fastened when the vehicle is braked, and the rotational energy of the drive system of the vehicle is regenerated to the rotational energy of the flywheel. By using it for driving the vehicle, the energy efficiency of the vehicle can be increased. In particular, before the frictional engagement element is fastened, the rotational speed difference for controlling the motor is reduced in advance so as to reduce the rotational speed difference between the first and second elements of the frictional engagement element. At the time of fastening with the element, energy loss due to heat generation caused by the difference in rotational speed between the two can be suppressed, which contributes to increase the energy efficiency of the vehicle.

  In this rotational speed difference control, before the braking of the vehicle, which is a regenerative control start condition, is started, the rotational speed difference increase is controlled in advance so as to suppress an increase in the rotational speed difference of the frictional engagement element. Suppression control can be used. In this case, since the rotational speed difference of the frictional engagement element is suppressed in advance, the frictional engagement element can be quickly engaged, and energy efficiency may be better than when the large rotational speed difference is reduced at once.

  Further, in the rotational speed difference control, when braking of the vehicle, which is a regenerative control start condition, is started, a fastening that controls the motor so as to reduce the rotational speed difference of the frictional engagement element immediately before fastening the frictional engagement element. Pre-control can be used. In some cases, such as when it takes time to establish the engagement condition of the frictional engagement element, the energy efficiency may be better than always suppressing the difference in rotational speed of the frictional engagement element.

It is a lineblock diagram of vehicles provided with a flywheel regeneration system concerning each embodiment of the present invention. It is a gear shift diagram explaining rotation speed difference increase suppression control by the flywheel regeneration system concerning a 1st embodiment of the present invention. It is a flowchart explaining the rotational speed difference increase suppression control by the flywheel regeneration system concerning 1st Embodiment of this invention. It is a 1st example of the time chart explaining the rotational speed difference increase suppression control by the flywheel regeneration system concerning 1st Embodiment of this invention. It is a 2nd example of the time chart explaining the rotational speed difference increase suppression control by the flywheel regeneration system concerning 1st Embodiment of this invention. It is a gear shift diagram explaining the pre-fastening control by the flywheel regeneration system concerning 2nd Embodiment of this invention. It is a flowchart explaining the pre-fastening control by the flywheel regeneration system concerning 2nd Embodiment of this invention. It is a 1st example of the time chart explaining the pre-fastening control by the flywheel regeneration system concerning 2nd Embodiment of this invention. It is the 2nd example of the time chart explaining pre-fastening control by the flywheel regeneration system concerning a 2nd embodiment of the present invention.

Embodiments of the present invention will be described below with reference to the drawings.
In the present invention, when the frictional engagement element is engaged, the motor is controlled in advance so as to reduce the difference in rotational speed between the two elements of the frictional engagement element. Two embodiments in which this control method is different will be described. . Since the hardware configuration of the devices according to these embodiments is the same, first, the hardware configuration of the device according to each embodiment will be described with reference to FIG. 1, and then the control according to each embodiment will be described.

[1. Configuration of vehicle according to each embodiment]
As shown in FIG. 1, a vehicle 100 includes an engine 1 as a power source, a flywheel 2 that regenerates energy, and a continuously variable transmission mechanism (CVT variator, hereinafter referred to as variator) that continuously changes the output rotation of the engine 1. 3) and a continuously variable transmission (CVT) 3A having a sub-transmission mechanism 4 for shifting the output rotation of the variator 3, a final reduction device 5 for decelerating the output rotation of the sub-transmission mechanism 4, and left and right drive wheels 6 And a hydraulic circuit 7 and a controller (control means) 8. A differential device (not shown) is interposed between the final reduction gear 5 and the left and right drive wheels 6.

  An engine clutch (friction engagement element) 91 is provided between the engine 1 and the CVT 3A. The engine clutch 91 is a hydraulic clutch whose fastening capacity can be controlled by the supplied hydraulic pressure. When the engine clutch 91 is in a fastening state, the driving force of the engine 1 is transmitted to the CVT 3A. In this example, an intermediate shaft 21 is provided between the output shaft (crankshaft) 11 of the engine 1 and the input shaft (input portion) 31 of the CVT 3A. 91 is interposed between the output shaft 11 and the intermediate shaft 21 of the engine 1. The gear pair 22 reverses engine rotation and transmits it to the input shaft 31 of the CVT 3 and is composed of gears having the same number of teeth. The input shaft 31 rotates at the same speed as the intermediate shaft 21 and the output shaft 11 of the engine 1. To do.

  An oil pump 10 that is driven by the rotation of the intermediate shaft 21 and generates hydraulic pressure is connected to the intermediate shaft 21. The oil pump 10 is constituted by, for example, a gear pump or a vane pump. The hydraulic pressure generated by the oil pump 10 is supplied to the variator 3, the engine clutch 91, the auxiliary transmission mechanism 4 and the like via a hydraulic circuit 7 described later.

  The flywheel 2 is further connected to the intermediate shaft 21 via reduction gear trains 23 and 24. The flywheel 2 is configured by accommodating a rotatable cylindrical body or a disk-shaped metal body in a container. The inside of the container is in a vacuum state or a reduced pressure state in order to reduce a decrease in rotation (also referred to as windage loss) due to air resistance or the like when the metal body rotates.

  Between the reduction gear train 23 and the reduction gear train 24, a flywheel clutch 92, which is a frictional engagement element used in a flywheel type regeneration system described later, is provided. The flywheel clutch 92 is a hydraulic clutch whose fastening capacity can be controlled by supplied hydraulic pressure. The engagement capacity of the flywheel clutch 92 is controlled by a hydraulic source capable of supplying hydraulic pressure regardless of the rotation of the intermediate shaft 21. Specifically, unlike the oil pump 10, the hydraulic pressure generated by the electric oil pump 10 </ b> E driven by the electric motor is supplied to the flywheel clutch 92. Note that the fastening capacity of the flywheel clutch 92 may be controlled not by the electric oil pump 10E but by an electric actuator.

  The sub-transmission mechanism 4 is a transmission mechanism that is connected to the output shaft 32 of the variator 3 and has two forward speeds and one reverse speed. The auxiliary transmission mechanism 4 is not shown in detail, but is connected to a Ravigneaux type planetary gear mechanism in which two planetary gear carriers are coupled, and a plurality of rotating elements constituting the Ravigneaux type planetary gear mechanism, and their linked state. And a plurality of frictional engagement elements (low brake, high clutch, reverse brake) for changing. When the hydraulic pressure supplied to each friction engagement element is adjusted and the engagement / release state of each friction engagement element is changed, the gear position of the subtransmission mechanism 4 is changed.

If no frictional engagement element in the subtransmission mechanism 4 is fastened, the CVT 3A, the final reduction gear 5 and the drive wheels 6 are powered off, and the output shaft of the subtransmission mechanism 4 (the output portion of the transmission 3A). Does not output any power. Therefore, the low brake or high clutch used at the start also functions as a start clutch.
Although not provided in this example, a torque converter with a lock-up clutch may be provided on, for example, the intermediate shaft 21 between the engine 1 and the CVT 3A.

  The hydraulic circuit 7 is constituted by a solenoid valve or the like that operates in response to a signal from a controller 8 to be described later, through an oil pump 10, a variator 3, an engine clutch 91, an auxiliary transmission mechanism 4, a flywheel clutch 92, and an oil path. Connected. The hydraulic circuit 7 generates the hydraulic pressure required by each pulley of the variator 3, the engine clutch 91 and the auxiliary transmission mechanism 4, using the hydraulic pressure generated by the oil pump 10 as a source pressure, and the generated hydraulic pressure is used for each pulley of the variator 3. , And supplied to the engine clutch 91 and the auxiliary transmission mechanism 4.

  The output shaft 11 of the engine 1 is connected with an alternator 12 and an air conditioner compressor 13 as auxiliary machines via a power transmission member (belt / pulley mechanism) 14. The alternator 12 is electrically connected to the battery 15, and the battery 15 is charged by the electric power generated by the alternator 12. A starter motor 18 is connected to the output shaft 11 of the engine 1 via a gear pair 17, and the engine 1 is started by the output rotation of the starter motor 18 when the engine is started.

  A motor (electric motor) 20 is connected to the flywheel 2. The motor 20 is connected to the battery 15 via the inverter 16. The inverter 16 controls the operation of the motor 20 so that the flywheel 2 rotates at the set rotation speed. Thereby, the rotation of the flywheel 2 is controlled by the motor 20 in a state where the flywheel clutch 92 is not connected. Here, a motor generator having a power generation mode is applied to the motor 20, and the battery 15 can be charged with the generated power by the rotational energy of the flywheel 2. Each rotation speed is also called a rotation speed because it is a rotation speed per unit time.

  The vehicle 100 is equipped with a brake device 60 that brakes each of the driving wheels 6 and driven wheels (not shown). The brake device 60 is an electronically controlled brake in which a brake pedal 61 and a master cylinder 62 are mechanically independent. When the driver depresses the brake pedal 61, a brake actuator 63 operated by control of the controller 8 described later displaces the piston of the master cylinder 62, and the driver depresses the brake pedal 61, that is, a hydraulic pressure corresponding to the required deceleration. Is supplied to the wheel cylinder 64 of each wheel, and the brake caliper 65 pinches the brake disc 66 to generate a braking force. The brake device 60 uses a servo system that uses the negative pressure of the engine 1 or the negative pressure of the electric vacuum pump when the engine 1 is stopped.

  The controller 8 includes a CPU, a RAM, an input / output interface, and the like. The controller 8 includes a rotational speed sensor 81 for detecting the rotational speed Ne of the engine 1, a rotational speed sensor 82 for detecting the rotational speed (input shaft rotational speed) Nin of the input shaft 31 of the CVT 3A, and the rotational speed of the flywheel 2 (flying speed). Wheel rotation speed) A rotation speed sensor 83 for detecting Nfw, a vehicle speed sensor 84 for detecting the vehicle speed VSP, an accelerator opening sensor 86 for detecting the opening APO of the accelerator pedal 85, and a driver's depressing force on the brake pedal 61. A signal from the brake sensor 87 or the like is input.

  The controller 8 performs various calculations based on the input signals, and controls the variator 3, the subtransmission mechanism 4, the engagement / release of the clutches 91 and 92, and the operation of the brake actuator 63. In particular, when the driver depresses the brake pedal 61 and the vehicle 100 decelerates, the controller 8 engages the flywheel clutch 92 and accelerates the rotation input from the drive wheels 6 by the reduction gear trains 23 and 24. The regenerative braking for regenerating the kinetic energy of the vehicle 100 with the flywheel 2 is performed by rotating the flywheel 2 and converting the kinetic energy of the vehicle 100 into the kinetic energy of the flywheel 2.

  At this time, as described later, the rotational speed of the drive wheel 6 is increased and inputted to the flywheel 2 by downshifting the speed ratio of the CVT variator 3 (hereinafter referred to as CVT speed ratio) to the Low side. The rotational speed of the flywheel 2, that is, the magnitude of the stored kinetic energy can be increased.

  During regeneration by the flywheel 2, the controller 8 controls the engagement capacity of the flywheel clutch 92 so as to obtain a braking force (regenerative brake) according to the driver's deceleration request. If the regenerative brake cannot be generated before the flywheel clutch 92 is engaged, or if the regenerative brake alone cannot satisfy the driver's deceleration request, the controller 8 operates the brake actuator 63 to apply the braking force of the brake 60. To increase the braking force according to the driver's deceleration request.

  The kinetic energy regenerated by the flywheel 2 can be stored as the rotation of the flywheel 2 by releasing the flywheel clutch 92. By engaging the flywheel clutch 92 while the kinetic energy is stored in the flywheel 2, the kinetic energy stored in the flywheel 2 is transmitted from the intermediate shaft 21 to the input shaft 31, and the vehicle 100 starts or It can be used for acceleration energy.

In particular, by appropriately selecting the mass of the flywheel 2 and the reduction gear ratios of the reduction gear trains 23 and 24, it is sufficient to start the heavy vehicle 100 in a state where the flywheel 2 is sufficiently rotating. Energy can be saved.
Thus, when the vehicle 100 decelerates, the controller 8 engages the flywheel clutch 92, and the kinetic energy of the vehicle 100 is regenerated to the kinetic energy of the flywheel 2.

  By the way, if there is a difference in rotational speed between the two fastening elements 92a and 92b of the flywheel clutch 92 at the start of fastening of the flywheel clutch 92, heat is generated between the fastening elements 92a and 92b during fastening, resulting in heat loss of energy. . Therefore, in the flywheel type regenerative system described later, the controller 8 controls the motor 20 so as to reduce the rotational speed difference between the two fastening elements 92a and 92b in advance when the flywheel clutch 92 is fastened. Implement control. Here, “reducing” the “rotational speed difference is reduced” means to reduce compared to the case where this control is not performed, and does not simply mean that the rotational speed difference is reduced. .

[2. Flywheel regeneration system according to each embodiment]
The flywheel regeneration system according to each embodiment includes a CVT 3 </ b> A, a flywheel clutch 92, a flywheel 2, a motor 20, and a controller 8. As described above, the controller 8 is engaged with the flywheel clutch 92 during braking of the vehicle, that is, when the brake pedal 61 is depressed, and the rotational energy of the drive system of the vehicle is converted to the rotational energy of the flywheel 2. Regenerative control is performed, and thereafter, regenerative control is performed in which the rotational energy regenerated on the flywheel is used to drive the vehicle.

  As described above, the regenerative control includes regenerative control in a stage of collecting rotational energy in the flywheel 2 and regenerative control in a stage of releasing the rotational energy collected in the flywheel 2 for driving the vehicle. The present invention relates to regenerative control in the energy recovery stage, and the regenerative control described in each embodiment is also the regenerative control in the energy recovery stage.

  Further, in the present flywheel type regeneration system, the motor 20 is not required to have a power generation function, and the engine clutch 91 is not essential. However, by providing the engine clutch 91, by releasing the engine clutch 91 during the regeneration control, the energy lost as the engine brake can be regenerated to the rotational energy of the flywheel clutch 92, and the regeneration efficiency can be improved.

  The flywheel clutch 92 couples or releases the first element 92a connected to the CVT 3A side and the second element 92b connected to the flywheel 92 side. The feature of this regeneration system is that in the regeneration control by the controller 8 When the flywheel clutch 92 is engaged, the motor 20 is controlled so as to reduce the rotational speed difference between the first element 92a and the second element 92b in advance. There are various control methods for reducing the rotational speed difference in advance. Hereinafter, rotational speed difference control for reducing the rotational speed difference in advance will be described as the first embodiment and the second embodiment.

[3. First Embodiment]
[3-1. Configuration (configuration of rotation control)]
The flywheel type regeneration system according to the present embodiment has the hardware configuration as described above. In the regeneration control by the controller 8, the two elements 92a of the flywheel clutch 92 are accompanied by a decrease in the rotational speed of the flywheel 2. , 92b, the motor 20 is controlled to suppress this increase when the difference in rotational speed increases.

Here, “suppressing the increase” is not limited to a form in which the rotational speed difference itself does not increase, for example, by keeping the rotational speed difference constant, but the increase in the case where the rotational speed difference increases is not limited. A form to reduce the amount is also included. Thereby, energy efficiency improvement and suppression of power consumption can be promoted. Needless to say, the rotational speed difference may be reduced. In this case, the above effect can be obtained more easily.
Hereinafter, this rotational speed difference control is referred to as rotational speed difference increase suppression control, and the present embodiment will be described focusing on this control.

  When the flywheel 2 is rotating, unless the rotational torque is applied, the rotational speed of the flywheel 2 is reduced by the decay of rotational energy, and the second element 92b of the flywheel clutch 92 connected to the flywheel 2 side is reduced. The rotational speed decreases. On the other hand, the first element 92a of the flywheel clutch 92 connected to the CVT 3A side varies in accordance with the rotational speed of the intermediate shaft 21, that is, the rotational speed of the input shaft 31 of the CVT 3A. Therefore, as long as the rotational speed of the input shaft 31 of the CVT 3A does not decrease similarly to the rotational speed of the flywheel 2, the rotational speed difference between the two elements 92a and 92b can be increased.

  Therefore, when the following control start condition is satisfied, the controller 8 performs rotational speed difference increase suppression control that suppresses an increase in rotational speed difference between the two elements 92a and 92b of the flywheel clutch 92.

(1) The vehicle is in an engine running state in which the vehicle runs with the driving force of the engine 1.
(2) The vehicle speed VSP is equal to or lower than the upper limit vehicle speed Vs.
(3) The flywheel clutch 92 is in the released state (OFF).
(4) The remaining capacity SOC of the battery 15 is within an appropriate range.
(5) The flywheel input shaft conversion rotational speed Nfwin is less than the target rotational speed Na used for control.
(6) The flywheel input shaft conversion rotational speed Nfwin is equal to or higher than the lower limit rotational speed Nlimit.

  In the rotational speed difference increase suppression control according to the present embodiment, when any of the above control start conditions is satisfied, the rotation of the motor 20 is controlled such that the flywheel input shaft equivalent rotational speed Nfwin matches the target rotational speed Na. This rotation control is characterized by the setting of the target rotation speed Na and each control start condition described above. Hereinafter, a specific method of the rotation speed difference increase suppression control will be described together with each control start condition.

  Note that this rotational speed difference increase suppression control is control performed before the flywheel clutch 92 is engaged, so the above condition (3) is a precondition, and this control uses the electric power of the battery 15 for the motor 20. From the viewpoint of protecting the battery 15, the above condition (4) is also a precondition. Hereinafter, the conditions (1), (2), (5), and (6) will be described.

  First, the flywheel input shaft converted rotational speed Nfwin is a value obtained by converting the flywheel rotational speed Nfw detected by the rotational speed sensor 83 into the rotational speed (input shaft rotational speed) Nin of the input shaft 31 of the CVT 3A. In the drive system of the vehicle 100, the input shaft rotational speed Nin is the center of each control. However, the reduction gear trains 23 and 24 are interposed between the flywheel 2 and the input shaft 31 of the CVT 3A. Is fastened, the rotation of the flywheel 2 is decelerated by the reduction gear trains 23 and 24 and transmitted to the input shaft 31. Therefore, when the rotational speed difference of the flywheel clutch 92 is viewed, the flywheel rotational speed Nfw and the input shaft rotational speed Nin cannot be directly compared.

  The rotational speed on the flywheel 2 side that is decelerated by the reduction gear trains 23, 24 can be obtained by correcting the flywheel rotational speed Nfw using the gear ratio of the reduction gear trains 23, 24. Wheel input shaft conversion rotational speed Nfwin. If this flywheel input shaft conversion rotational speed Nfwin coincides with the input shaft rotational speed Nin, the rotational speed difference between the first element 92a and the second element 92b of the flywheel clutch 92 is eliminated.

  Next, the target rotation speed Na will be described. The target rotational speed Na is a speed change line (also referred to as a coast line) Lc when the vehicle is off the accelerator (that is, when coasting) and a rotational speed that secures an oil amount balance of the pump 10 (an oil amount balance secured rotational speed). It is determined according to a control target line La defined by Np and the upper limit vehicle speed Vs.

The reason for paying attention to the coast line Lc is as follows.
The condition for engaging the flywheel clutch 92 for regeneration is that the brake pedal 61 is depressed (brake on) when the vehicle speed VSP is equal to or higher than the lower limit vehicle speed Vs0, but switching from accelerator on to accelerator off is performed. Later, there is a case where the brake is turned on immediately after the brake is turned on, or a case where the brake is turned on after the accelerator is turned on through the coasting state where the accelerator is turned off and the brake is turned off (so-called coasting state). If the accelerator is off, the shift line (coast line) when the accelerator opening is 0 is used for the shift control, both in the coasting state and when the brake is on. Note that the condition for engaging the flywheel clutch 92 that the vehicle speed VSP is equal to or higher than the lower limit vehicle speed Vs0 is that if the vehicle speed VSP is too low, the energy loss is greater than the amount of rotational energy recovered in the flywheel 2. Because.

  In other words, the shift control is performed as shown by a two-dot chain line in the shift diagram of FIG. 2, for example, the input shaft rotation speeds of shift lines (ie, vehicle speed VSP and CVT 3A (variator 3)) corresponding to the accelerator opening. This is performed in accordance with Nin (in this embodiment, a line defining a correspondence relationship (speed ratio) with engine rotational speed Ne). In the coasting state where the depression of the accelerator pedal 85 is released, the coast line Lc, which is a shift line when the accelerator opening is 0, is used. The coast line Lc is positioned on the side of the highest line (most overdrive line) Lh among the shift lines corresponding to each accelerator opening. However, the coast line Lc is located on the lower gear ratio side (the side on which the input shaft rotation speed Nin is higher) than the highest line Lh in order to ensure a minimum engine rotation speed that does not hinder engine operation at low vehicle speeds. This is a case where the vehicle speed VSP is less than the predetermined vehicle speed Vs1 in FIG.

  When the accelerator is off, the shift control is performed so that the input shaft rotational speed Nin becomes the rotational speed (coast line corresponding rotational speed) Nc corresponding to the vehicle speed VSP according to the coast line Lc. For this reason, if the flywheel input shaft conversion rotational speed Nfwin coincides with the coastline-corresponding rotational speed Nc when the coasting state is entered, the distance between the first element 92a and the second element 92b of the flywheel clutch 92 is determined. No difference in rotational speed occurs.

  Therefore, the target rotational speed Na is set to the coast line-corresponding rotational speed Nc, and the engine is running before the coast running state (condition (1) above), in advance, the flywheel input shaft conversion rotational speed. Nfwin is controlled to coincide with the coast line corresponding rotation speed Nc. When the coasting state is subsequently reached, the input shaft rotational speed Nin is controlled to the coastline corresponding rotational speed Nc. Therefore, if the flywheel input shaft equivalent rotational speed Nfwin matches the coastline corresponding rotational speed Nc. The difference in rotational speed of the flywheel clutch 92 is eliminated.

  However, as shown in FIG. 2, in an even lower vehicle speed region (when the vehicle speed VSP is less than the predetermined vehicle speed Vs2 in FIG. 2), an oil amount balance ensuring rotation speed Np that is higher than the coast line Lc is set. ing. When the vehicle speed VSP enters this low vehicle speed region, the target rotational speed Na is set to the oil amount balance ensuring rotational speed Np, and the input shaft equivalent rotational speed Nfwin of the flywheel 2 is held at or above the oil amount balance ensuring rotational speed Np. This oil amount balance securing rotation speed Np is prepared for a situation where the input shaft rotation speed Nin decreases, the amount of oil discharged from the pump 10 decreases, and the oil amount balance becomes insufficient.

  That is, in order to downshift the CVT gear ratio to the Low side after the flywheel clutch 92 is engaged for regeneration, hydraulic oil is used for this downshift, so that no slip occurs in the variator 3 or the subtransmission mechanism 4. The required oil amount of the entire system increases with respect to the oil amount required for the system. Since the pump 10 is rotationally driven by the input shaft 31, when the input shaft rotational speed Nin decreases, the amount of oil discharged from the pump 10 also decreases. On the coast line Lc in the low vehicle speed region, the amount of oil discharged from the pump 10 cannot be ensured by an amount necessary for shifting the variator 3 at a desired shift speed, which hinders the change of the CVT gear ratio.

Therefore, the lower limit value of the rotational speed at which the discharge flow rate necessary for shifting the variator 3 at a desired speed is secured is the oil amount balance securing rotational speed Np, and the rotational speed of the input shaft 31 is increased to reduce the required oil amount. It is prepared so that it can be secured. Accordingly, a difference in rotational speed of the flywheel clutch 92 occurs. Under this circumstance, however, emphasis is placed on securing the amount of oil discharged from the pump 10 rather than eliminating the heat loss caused by the difference in rotational speed. Thereby, after the flywheel clutch 92 is engaged, the CVT gear ratio can be changed without any trouble.
It will be resolved.

  Further, as indicated by the lower limit rotational speed line Llimit in FIG. 2, the lower limit rotational speed Nlimit, which is a condition for executing the rotational speed difference increase suppression control, is set corresponding to the vehicle speed, and the rotational speed difference increase suppression control is started. Sometimes, the rotational speed difference increase suppression control is performed only when the flywheel input shaft conversion rotational speed Nfwin is equal to or higher than the lower limit rotational speed Nlimit (the above condition (6)). This is because when the flywheel input shaft conversion rotational speed Nfwin does not reach the lower limit rotational speed Nlimit, the rotational speed difference between the two fastening elements 92a and 92b is large, and the small motor 20 is low in terms of cost and mountability. This is because the flywheel input shaft conversion rotational speed Nfw cannot be increased to the target rotational speed Na, and there is a possibility that the control cannot be reliably achieved.

  Even if a large motor is mounted, if the rotational speed difference between the two fastening elements 92a and 92b is large, the amount of heat generated until the fully engaged state is large, and the durability of the flywheel clutch 92 is large. It is because there exists a possibility that it may fall. From this point, the lower limit rotational speed Nlimit is set to a value reduced from the target rotational speed Na by a rotational speed that can increase the flywheel rotational speed Nfw to the target rotational speed Na according to the output of the mounted motor. Is done. However, if the rotational speed difference between the set lower limit rotational speed Nlimit and the target rotational speed Na may decrease the durability of the flywheel clutch 92 during engagement, the lower limit rotational speed is set so that the durability does not decrease. Increase the speed Nlimit. Furthermore, as a reason why the rotational speed difference increase suppression control is not performed when the flywheel rotational speed Nfw does not reach the lower limit rotational speed Nlimit, if the rotational speed difference between the two fastening elements 92a and 92b is large, the power consumption by the motor 20 This is because, since the vehicle is in a low vehicle speed range, start and acceleration by the driver are often required, and there is a high possibility that the opportunity to regenerate flywheel rotational energy is lost.

The inertia moment of the flywheel 2 is set to Ifwv, and the angular speed ω corresponding to the rotational speed of the flywheel 2 is increased from the lower limit angular speed ωlimit corresponding to the lower limit rotational speed Nlimit to the angular speed ωc corresponding to the rotational speed corresponding to the coast line Lc. though, it is assumed to apply for the time t, the output of the motor 20 required for the angular velocity increase of the flywheel 2 (rotational speed increase) as P _1, paying attention to the increase in energy consumption and kinetic energy of the flywheel 2 of the motor 20, The following formula (1 ′) is established.

P ₁ · t = Ifwv / (ωc ² −ωlimit ² ) (1 ′)
Therefore, formula (1) is derived.
P ₁ = (Ifwv / t) · (ωc ² −ωlimit ² ) (1)
As can be seen from the equations (1 ′) and (1), the larger the difference between the angular velocity ωc and the lower limit angular velocity ωlimit, the more required the output P _{1 of the} motor 20 and the time t required to increase the rotational speed. Is set.

Further, the output P ₂ dissipated by the friction torque Tfric of the flywheel 2 of the output P of the motor, as shown in the following expression (2), the product of the friction torque Tfric and angular velocity ωc of the flywheel 2.
P ₂ = Tfric · ωc (2)

The consumption power P _2, the higher the angular velocity ωc increases, i.e., as the vehicle speed VSP increases, increases, the output P ₁ to be used for the angular velocity increase of the flywheel 2 (rotational speed increase), the output P of the motor since the consumption output P ₂ becomes a value obtained by subtracting (P-P ₂₎ from the more angular ωc increases, i.e., as the vehicle speed VSP increases, the output P ₁ to be used for the rotational speed increase of the flywheel 2 Becomes smaller.

  Thus, as the vehicle speed VSP increases, the lower limit rotational speed Nlimit that can increase the flywheel input shaft equivalent rotational speed Nfwin to the control target line La within a predetermined time t by the motor 20 approaches the control target line La, and the vehicle speed VSP. Reaches the upper limit vehicle speed Vs, all the output P of the motor 20 is consumed by the friction torque Tfric. Therefore, rotation control (rotational speed difference increase suppression control) of the flywheel 2 is performed on condition that the vehicle speed VSP is equal to or lower than the upper limit vehicle speed Vs (the above condition (2)).

  If the flywheel input shaft equivalent rotational speed Nfwin is equal to or higher than the target rotational speed Na, it is not necessary to increase the rotational speed of the flywheel 2 by the motor 20, and the flywheel input shaft equivalent rotational speed Nfwin is less than the target rotational speed Na. On the condition (condition (5) above), the rotational speed difference increase suppression control is performed.

[3-2. Action and Effect]
[3-2-1. flowchart]
Next, rotation control (rotational speed difference increase suppression control) of the flywheel 2 through the motor 20 by the controller 8 will be described with reference to the flowchart of FIG.
As shown in FIG. 3, the controller 8 first determines the start condition of the rotational speed difference increase suppression control.

  That is, it is determined whether or not the vehicle speed VSP is equal to or lower than the upper limit vehicle speed Vs (condition (2)) and the engine is running (condition (1)) (step A10). Here, if the vehicle speed VSP is equal to or lower than the upper limit vehicle speed Vs and the engine is running, it is determined whether or not the flywheel clutch 92 is off (disengaged) (condition (3)) (step A20). If the flywheel clutch 92 is off, it is determined whether or not the remaining capacity SOC of the battery 15 is within an appropriate range (condition (4)) (step A30). If the remaining capacity SOC of the battery 15 is within an appropriate range, it is determined whether or not the flywheel input shaft equivalent rotational speed Nfwin is less than the target rotational speed Na (condition (5)) (step A40). If the flywheel input shaft equivalent rotational speed Nfwin is less than the target rotational speed Na, it is determined whether or not the flywheel input shaft equivalent rotational speed Nfwin is equal to or higher than the lower limit rotational speed Nlimit (condition (6)) (step A50). .

In this way, when any of the control conditions (1) to (6) is satisfied, the rotational speed difference increase suppression control (steps A60 to A90) is performed. Any of the control conditions (1) to (6) is performed. If not established, the rotational speed difference increase suppression control (steps A60 to A90) is not performed.
In the rotational speed difference increase suppression control, first, the target rotational speed Na of the flywheel input shaft equivalent rotational speed Nfwin is set to the coast line corresponding rotational speed Nc based on the vehicle speed VSP and the coast line Lc at this time (step A60). .

Next, it is determined whether or not the coast line corresponding rotational speed Nc is less than the pump oil amount balance securing rotational speed Np (step A70). If the coast line-corresponding rotational speed Nc is less than the pump oil amount balance securing rotational speed Np, the target rotational speed Na of the flywheel input shaft equivalent rotational speed Nfwin is set to this pump oil amount balance securing rotational speed Np (step A80). ).
Then, control is performed so that the motor 20 is in the maximum output state and the flywheel input shaft equivalent rotation speed Nfwin becomes the target rotation speed Na (step A90).

  After such control, when the accelerator travels from the accelerator-on state to the coast-off state where the accelerator is off, shift control is performed so that the input shaft rotational speed Nin becomes the coast line-corresponding rotational speed Nc. If the coastline-corresponding rotational speed Nc is equal to or greater than the pump oil amount balance securing rotational speed Np and the target rotational speed Na is set to the coastline-corresponding rotational speed Nc, the flywheel input shaft equivalent rotational speed Nfwin is as follows. Since the corresponding rotational speed Nc is controlled, there is no rotational speed difference between the first element 92a and the second element 92b of the flywheel clutch 92.

  Thereafter, when the brake pedal 61 is depressed by the driver, the controller 8 determines this from the information of the brake switch 87, engages the flywheel clutch 92, and reduces the rotation input from the drive wheels 6 to the reduction gear train 23. , 24, the flywheel 2 is rotated and the kinetic energy of the vehicle 100 is converted into the kinetic energy of the flywheel 2 so that the kinetic energy of the vehicle 100 is recovered by the flywheel 2 and regenerative braking is performed. To do.

  When the flywheel clutch 92 is engaged, there is no rotational speed difference between the first element 92a and the second element 92b of the flywheel clutch 92, so energy loss due to heat generation due to the rotational speed difference between the two elements is reduced. This can suppress the energy efficiency of the vehicle.

  Further, if the coastline-corresponding rotational speed Nc is less than the pump oil amount balance securing rotational speed Np, the target rotational speed Na of the flywheel input shaft equivalent rotational speed Nfwin is set to this pump oil amount balance securing rotational speed Np. Since the flywheel input shaft conversion rotational speed Nfwin is controlled to become the target rotational speed Na, the rotational speed of the input shaft 31 is increased and the amount of oil discharged from the pump 10 is ensured when the flywheel clutch 92 is subsequently engaged. Is done.

  As a result, the CVT variator 3 can transmit the driving force and change the transmission gear ratio without any trouble without causing a shortage of the oil amount balance, and the gear ratio intended by the driver is immediately obtained based on the intention to start and accelerate from the driver. The speed can be changed at a desired speed, and the time lag until the driving force is generated for the start and acceleration intentions from the driver can be shortened to ensure the driving force of the vehicle. Further, the oil quantity balance is not insufficient in the variator 3 and the auxiliary transmission mechanism 4, and during the regeneration control for regenerating rotational energy in the flywheel 2, the deceleration due to the regeneration control slips between the variator 3 and the auxiliary transmission mechanism 4. Therefore, it is possible to achieve the degree of deceleration demand intended by the driver.

[3-2-1. Time chart]
Next, a specific example of the control according to the present embodiment will be described with reference to the time charts of FIGS. FIG. 4 shows a case where the coast line corresponding rotational speed Nc is equal to or higher than the pump oil amount balance securing rotational speed Np and the target rotational speed Na is set to the coast line corresponding rotational speed Nc, and FIG. 5 is a coast line corresponding rotational speed. The case where the speed Nc is less than the pump oil amount balance ensuring rotation speed Np and the target rotation speed Na is set to the pump oil amount balance ensuring rotation speed Np is shown. Nfwin when the rotational speed difference increase suppression control is not performed when the flywheel input shaft conversion rotational speed Nfwin falls below the target rotational speed Na is indicated by a two-dot chain line.

As shown in FIG. 4, when the accelerator pedal is depressed while the accelerator pedal is depressed, the CVT gear ratio is gradually shifted to the high side while the vehicle speed VSP is increased, and the engine rotational speed Ne and the input shaft rotational speed Nin are increased. when the target rotational speed Na is set to coast line-corresponding rotation speed Nc, the motor 20 at time t ₁₁ to the flywheel input shaft converted rotational speed Nfwin falls below the target rotational speed Na (coast line corresponding rotational speed Nc) is actuated Then, the rotational speed difference increase suppression control is started. At a later point in time t _12, off the accelerator is from on, the brake is switched from OFF to ON, when the coasting state, the shift control is line as the input shaft rotation speed Nin becomes coasting line-corresponding rotation speed Nc Is called.

The shift control, at a later point in time t _13, when input shaft rotation speed Nin becomes coasting line-corresponding rotation speed Nc, this time, since the flywheel input shaft converted rotational speed Nfwin is controlled to coast line corresponding rotational speed Nc The rotational speed difference between the first element 92a and the second element 92b of the flywheel clutch 92 is not generated.

Therefore, at this time t _13, releases the engine clutch 91, by entering into the flywheel clutch 92, the two elements 92a of the flywheel clutch 92, to suppress the energy loss due to heat generation caused by the rotational speed difference between the 92b This contributes to increasing the regenerative efficiency of the rotational energy of the flywheel 2. Further, here, since the timing for fastening the flywheel clutch 92 at the time t ₁₃ is switched to release the engine clutch 91 from engagement, it regenerated the kinetic energy of the flywheel clutch 92 to the energy content that is consumed by the engine brake.

As shown in FIG. 5, from the state where the accelerator is on and the vehicle speed VSP increases and the CVT gear ratio gradually shifts to the high side, and the engine rotational speed Ne and the input shaft rotational speed Nin increase, the time t ₂₁ When the accelerator is off and the vehicle is in a coasting state, the CVT gear ratio is controlled along the coast line. Therefore, the input shaft rotation speed Nin from a later time t ₂₂ is controlled to coast line corresponding rotational speed Nc. Further, the CVT gear ratio shifts to the low side as the vehicle speed decreases.

When the CVT gear ratio is near the lowest position, the coast line corresponding rotational speed Nc decreases, and the input shaft rotational speed Nin also decreases. For this reason, the input shaft rotational speed Nin eventually falls below the pump oil amount balance securing rotational speed Np (time point t ₂₃ ). On the other hand, from the time t _23, since the target rotational speed Na is set to pump oil amount balance ensuring rotational speed Np, flywheel input shaft converted rotational speed Nfwin is maintained at the pump oil amount balance ensuring rotational speed Np. A dotted line indicates Nfwin when the rotational speed difference increase suppression control is not performed when the flywheel input shaft equivalent rotational speed Nfwin falls below the oil amount balance securing rotational speed Np.

Thus, the brake at a later point in time t ₂₄ is switched from OFF to ON, the flywheel clutch 92 regeneration control is started is fastened, the input shaft rotation speed Nin is flywheel input shaft converted rotational speed Nfwin pump It is pulled up by the rotation of the flywheel 2 maintained at the oil amount balance securing rotation speed Np. Thus, the rotational speed of the input shaft 31 that drives the pump 10 is increased, and the amount of oil discharged from the pump 10 is ensured.

  As a result, when the flywheel clutch 92 is engaged, there is no shortage of the oil amount balance, the driving force transmission and the change of the gear ratio in the CVT variator 3 can be performed without any trouble, and based on the start and acceleration intention from the driver Immediately, the gear can be shifted to a gear ratio intended by the driver at a desired speed, and the time lag until the driving force is generated in response to the start and acceleration requests from the driver can be shortened to ensure the driving force of the vehicle. Further, while the flywheel clutch 92 is disengaged, the flywheel input shaft equivalent rotational speed Nfwin is maintained at the oil amount balance securing rotational speed Np, so that the amount of oil discharged from the oil pump 10 is secured, Subsequent regeneration control by the flywheel 2 can be started.

[3-3. Others]
In the present embodiment, the controller 8 includes a function (prediction means) for predicting that the vehicle 100 will subsequently travel at a reduced speed, and the control start condition includes that the prediction means has predicted a reduced speed travel. You may do it. In this case, the deceleration traveling can be predicted based on information (navigation information) of a navigation system mounted on the vehicle 100. Specifically, after obtaining information from the navigation information that the front is congested, that there is a red light ahead, or that there is a corner ahead, it is predicted that the vehicle 100 will subsequently decelerate. be able to.

  As described above, by including that the deceleration running is predicted in the control start condition of the rotation speed difference increase suppression control, the rotation speed difference increase suppression control can be effectively used. That is, in the rotational speed difference increase suppression control, the motor 20 is operated using the electric power of the battery 15, so that the electrical energy of the battery 15 is lost as much as the rotational speed difference increase suppression control is performed for a long time. However, the rotational speed difference increase suppression control is performed only for a short period immediately before the start of the deceleration travel by brake-on by performing the rotational speed difference increase suppression control only when the prediction unit predicts the deceleration travel. Thus, the effect of the rotational speed difference control can be obtained, the consumption of electric energy of the battery 15 can be suppressed, and the energy efficiency is improved.

[4. Second Embodiment]
[4-1. Configuration (configuration of rotation control)]
The flywheel regenerative system according to the present embodiment has the hardware configuration as described above as in the first embodiment. In the regenerative control by the controller 8, just before the flywheel clutch 92 is engaged during braking of the vehicle 100. When the control start condition including that the rotational speed of the flywheel (here, the flywheel input shaft equivalent rotational speed Nfwin described in the first embodiment) is lower than the target rotational speed Na is satisfied, The motor 20 is controlled so that the rotational speed difference between the elements 92a and 92b is reduced. Hereinafter, this rotational speed difference control is referred to as pre-engagement control, and the present embodiment will be described focusing on this control.

When the following control start condition is satisfied, the controller 8 according to the present embodiment is instructed to engage the flywheel clutch 92 when the vehicle 100 is braked. The pre-engagement control for reducing the rotational speed difference between the two elements 92a and 92b is performed.
(1) The brake is turned on.
(2) The flywheel clutch 92 is in a released state or not fully engaged.
(3) The flywheel clutch 92 is instructed to be engaged.
(4) The remaining capacity SOC of the battery 15 is within an appropriate range.

  In the pre-engagement control according to the present embodiment, the rotation of the motor 20 is controlled such that the flywheel input shaft equivalent rotational speed Nfwin approaches the target rotational speed Na when any of the above control start conditions is satisfied. This rotation control is performed for a minute time immediately before starting the regenerative control in which the flywheel clutch 92 is engaged and the rotational energy is collected in the flywheel 2 when the vehicle 100 with the brake pedal 61 depressed is braked. Since the operation is delayed, it is also necessary to coordinate the braking by the brake device 60 and the braking by the regenerative control. Hereinafter, a specific method of the pre-engagement control will be described.

  Since the pre-engagement control is a control that is performed when the flywheel clutch 92 is instructed to be engaged, the above condition (3) is a precondition. Since the engagement command for the flywheel clutch 92 is based on the condition that the brake on and the vehicle speed VSP are equal to or higher than the lower limit vehicle speed Vs0, the condition (3) can be replaced with “the vehicle speed VSP is equal to or higher than the lower limit vehicle speed Vs0”. . Moreover, since this control operates the motor 20 using the electric power of the battery 15, the above condition (4) is also a precondition from the viewpoint of protecting the battery 15. Condition (2) will be described below.

First, the target rotation speed Na will be described. As described in the first embodiment, the target rotational speed Na is determined according to the control target line La defined by the shift line (coast line) Lc when the accelerator of the vehicle is off (that is, during coasting). .
The reason for paying attention to the coast line Lc is the same as in the first embodiment.

  That is, the condition for engaging the flywheel clutch 92 for regeneration is when the vehicle speed VSP is equal to or higher than the lower limit vehicle speed Vs0 and the brake pedal 61 is depressed, and in this case, it is assumed that the accelerator is off. Become. When the accelerator is off, a shift line (coast line) when the accelerator opening is 0 is used for the shift control, whether in the coasting state or when the brake is on.

  When the flywheel clutch 92 is engaged, if the flywheel input shaft equivalent rotational speed Nfwin matches the rotational speed (coast line corresponding rotational speed) Nc according to the coast line Lc, the first of the flywheel clutch 92 is set. There is no rotational speed difference between the element 92a and the second element 92b. Further, if the flywheel input shaft equivalent rotational speed Nfwin approaches even if it does not coincide with the coast line corresponding rotational speed Nc, the influence of the rotational speed difference between the first element 92a and the second element 92b is reduced.

  Therefore, as shown in FIG. 6, the target rotational speed Na is set to the coast line corresponding rotational speed Nc, and the flywheel input shaft equivalent rotational speed Nfwin is set to the coast line corresponding rotational speed Nc before the flywheel clutch 92 is engaged. Control to approach. This “control to approach” means that the flywheel input shaft conversion rotational speed Nfwin does not necessarily coincide with the coast line corresponding rotational speed Nc. This is because the electric power consumed by the motor 20 in the pre-engagement control is considered so as not to be excessive.

  In other words, in the pre-engagement control, the motor 20 is operated to increase the flywheel input shaft conversion rotational speed Nfwin so as to approach the target rotational speed Na (coast line-corresponding rotational speed Nc). Consumes 15 powers. The reason why the flywheel input shaft equivalent rotational speed Nfwin is increased is to suppress the rotational speed difference between the first element 92a and the second element 92b and to reduce the heat loss energy when the flywheel clutch 92 is engaged. However, if too much power energy is used to increase the flywheel input shaft equivalent rotational speed Nfwin, the reduction in heat loss energy will be exceeded.

  Therefore, the power consumption of the battery 15 used when raising the flywheel input shaft conversion rotational speed Nfwin is suppressed so as to increase the energy balance. As a result, the flywheel input shaft conversion rotational speed Nfwin approaches the coast line corresponding rotational speed Nc, but may not coincide. In the present embodiment, as a means for suppressing the power consumption of the battery 15, the pre-engagement control is performed within a specified time.

  When the flywheel input shaft conversion rotational speed Nfwin is increased, the output torque of the motor 20 is basically operated in the maximum output state or a state close to this in order to increase the rotational speed in a short time. . However, the maximum output torque of the motor 20 in this case is regulated by the remaining capacity SOC of the battery 15. That is, even if the remaining capacity SOC is within an appropriate range, the maximum output torque of the motor 20 is suppressed if the remaining capacity SOC is low. Further, when the remaining capacity SOC is out of the proper range during the pre-engagement control, the pre-engagement control is terminated at that time. In such a case, since the maximum output torque of the motor 20 itself decreases, the flywheel input shaft conversion rotational speed Nfwin may not reach the target rotational speed Na within a specified time.

  On the other hand, if the flywheel input shaft conversion rotational speed Nfwin is close to the target rotational speed Na, the output torque of the motor 20 can be suppressed even when the remaining capacity SOC is low. Therefore, the output torque of the motor 20 in the pre-engagement control may be adjusted based on the deviation between the flywheel input shaft equivalent rotational speed Nfwin and the target rotational speed Na. Further, if the flywheel input shaft conversion rotational speed Nfwin is equal to or higher than the target rotational speed Na, control before fastening is not necessary.

  Further, as described above, when the remaining capacity SOC is low, or when the vehicle speed is high and the flywheel input shaft conversion rotational speed Nfwin is greatly separated from the target rotational speed Na, the flywheel input is controlled by the pre-engagement control. Although the shaft-converted rotational speed Nfwin approaches the coast line-corresponding rotational speed Nc, there are cases where they do not coincide with each other. In this case, after the pre-engagement control, the flywheel clutch 92 is completely engaged while being slipped.

  Further, in the pre-engagement control, when the flywheel input shaft conversion rotational speed Nfwin is brought close to the target rotational speed Na, or after the pre-engagement control, when the flywheel clutch 92 is completely engaged while slipping, the CVT is performed only for a short time. The gear ratio (pulley ratio) is fixed to that at the vehicle speed at the start of flywheel regeneration. Therefore, as the vehicle speed VSP decreases, the input shaft rotational speed Nin decreases along the broken line in FIG. 6 and becomes a rotational speed Nco lower than the input shaft rotational speed Nc at the start of flywheel regeneration. As a result, the flywheel input shaft equivalent rotational speed Nfwin quickly reaches the target rotational speed Na.

[4-2. Action and Effect]
[4-2-1. flowchart]
Next, rotation control (rotational speed difference increase suppression control) of the flywheel 2 through the motor 20 by the controller 8 will be described with reference to the flowchart of FIG.
As shown in FIG. 7, the controller 8 first determines the start condition of the pre-engagement control.

  That is, whether the brake is on (condition (1)) or not (step B10), the flyhole clutch 92 is not completely engaged (that is, the flywheel clutch 92 of condition (2) is in the released state). Or whether the flywheel clutch 92 is instructed to be engaged (condition (3)) (step B30), and the remaining capacity SOC of the battery 15 is within an appropriate range. It is determined whether or not there is (condition (4)) (step B40).

  If any of these conditions is satisfied, the timer is started to start the timer count (step B50), and the timer count value T is compared with the threshold value T0 corresponding to the specified time (step B60). If the timer count value T is less than the threshold value T0, the pre-engagement control for operating the motor 20 to raise the flywheel input shaft equivalent rotational speed Nfwin and bring it close to the target rotational speed Na is performed (step B70).

  Thereafter, it is determined whether the flywheel input shaft equivalent rotational speed Nfwin matches the fixed rotational speed Nco (≈target rotational speed Na) (step B80), and if the flywheel input shaft equivalent rotational speed Nfwin matches the fixed rotational speed Nco. Then, the flywheel clutch 92 is completely engaged (step B90), the timer is stopped and the timer count value T is reset to 0 (step B100), and the control ends. When the flywheel input shaft conversion rotational speed Nfwin coincides with the fixed rotational speed Nco, the rotational speed difference between the first element 92a and the second element 92b of the flywheel clutch 92 is not generated, and the rotational speed difference is reduced. Energy loss due to the generated heat can be suppressed.

  On the other hand, the conditions (1), (2), and (3) are all satisfied, but if the condition (4) is not satisfied, the motor 20 cannot be operated. Even when the timer count value T is equal to or greater than the threshold value T0, the motor 20 is not operated from the viewpoint of suppressing power consumption. Therefore, the flywheel clutch 92 is slip-engaged to bring the flywheel input shaft equivalent rotational speed Nfwin closer to the fixed rotational speed Nco (step B72). In this case, fastening is performed while slipping according to the required deceleration. Thereafter, it is determined whether or not the flywheel input shaft equivalent rotational speed Nfwin matches the fixed rotational speed Nco (step B80). If the flywheel input shaft equivalent rotational speed Nfwin matches the fixed rotational speed Nco, the flywheel clutch 92 is turned on. Completely engaged (step B90), the timer is stopped and the timer count value T is reset to 0 (step B100), and the control is terminated.

  Even when the flywheel input shaft equivalent rotational speed Nfwin does not coincide with the fixed rotational speed Nco, if the pre-engagement control (step B70) is performed even a little, the flywheel clutch 92 between the first element 92a and the second element 92b Since the rotational speed difference is reduced, energy loss due to heat generation due to the rotational speed difference at the time of slip fastening in step B72 can be suppressed.

[4-2-1. Time chart]
Next, a specific example of control according to the present embodiment will be described with reference to the time charts of FIGS. FIG. 8 shows the case where the flywheel input shaft equivalent rotational speed Nfwin matches the fixed rotational speed Nco (≈target rotational speed Na) by the pre-engagement control, and FIG. 9 shows the flywheel input shaft equivalent rotational speed Nfwin by the pre-engagement control. A case where the rotational speed does not coincide with the fixed rotational speed Nco (≈target rotational speed Na) is shown.

As shown in FIG. 8, in the case where the vehicle speed is lower than the lower limit vehicle speed Vs0, the accelerator pedal is depressed (accelerator on), the vehicle speed VSP increases and the CVT gear ratio gradually shifts to the high side. the input shaft speed Nin is increased, in the state in which the target rotational speed Na is set to coast line corresponding rotational speed Nc, at time t _31, the accelerator is turned off from on, the brake is switched from off to on. As a result, the regenerative control start condition is satisfied. From this point, the CVT gear ratio is controlled toward the coast line.

Here, if the remaining capacity SOC of the battery 15 is appropriate region, the engine clutch 91 is turned off at the timing t ₃₂ to the engine clutch 91 is turned off (released), the flywheel input motor 20 is activated Pre-engagement control is performed in which the shaft-converted rotational speed Nfwin is increased to approach the target rotational speed Na. The pre-engagement control is limited to a predetermined time, and the CVT gear ratio is fixed during this period.

At time t ₃₃ , the flywheel input shaft equivalent rotational speed Nfwin matches the fixed rotational speed Nco (≈target rotational speed Na), so the motor 20 is stopped and the flywheel clutch 92 is turned on (engaged). . Thereby, energy loss due to heat generation does not occur when the flywheel clutch 92 is engaged. The kinetic energy of the vehicle 100 is recovered as rotational energy by the flywheel 2 and regenerative braking is performed, so that the recovered energy vehicle can be used effectively for starting and acceleration. Note that the service brake of the brake device 60 operates from when the brake is turned on until the regenerative brake is operated.

Also in the example shown in FIG. 9, when the vehicle speed is lower than the lower limit vehicle speed Vs0, the accelerator pedal is depressed (accelerator on), and the CVT gear ratio is gradually shifted to the high side while the vehicle speed VSP increases, and the engine speed Ne and the input shaft speed Nin is increased, in the state in which the target rotational speed Na is set to coast line corresponding rotational speed Nc, at time t _41, the accelerator is turned off from on, the brake is switched from off to on. As a result, the regenerative control start condition is satisfied. From this point, the CVT gear ratio is controlled toward the coast line.

Here, it is assumed that the remaining capacity SOC of the battery 15 is in an appropriate region but is small. Engine clutch 91 is turned off, the timing t ₄₂ to the engine clutch 91 is turned off (released), the motor 20 is activated by engagement before the control to bring the flywheel input shaft converted rotational speed Nfwin the pulling target rotational speed Na To implement. The pre-engagement control is limited to a predetermined time, and the CVT gear ratio is fixed during this period.

While the motor 20 is the motor 20 is stopped at time t ₄₃ after a predetermined time since the start, the maximum output torque of the motor 20 for the remaining capacity SOC is small is restricted, fly in time t ₄₃ wheel input shaft converted rotational speed Nfwin has not reached the target rotational speed Na. In this case, it closes the flywheel input shaft converted rotational speed Nfwin a fixed rotational speed Nco by the time t ₄₃ after the flywheel clutch 92 is slip-engaged.

Once t _44, the flywheel input shaft converted rotational speed Nfwin are Once coincides with fixed rotational speed Nco (≒ target rotational speed Na), the flywheel clutch 92 is turned ON (engagement). Since the rotational speed difference between the flywheel input shaft equivalent rotational speed Nfwin and the fixed rotational speed Nco is reduced by the amount of time that the pre-engagement control is performed for a predetermined time, energy loss due to heat generation when the flywheel clutch 92 is engaged is reduced. And the kinetic energy of the vehicle 100 is collect | recovered as rotational energy with the flywheel 2, and it can utilize effectively for starting and acceleration of the collect | recovered energy vehicle after that by implementing regenerative braking. Note that the service brake of the brake device 60 operates from when the brake is turned on until the regenerative brake is operated. In particular, when the flywheel clutch 92 is slip-engaged and the flywheel clutch 92 is slip-engaged and the braking operation amount intended by the driver cannot be realized, the regenerative braking force and service for slip-engaging the flywheel clutch 92 are determined. Coordinate the braking force of the brake.

[4-3. Others]
In the present embodiment, the energy consumption by the pre-engagement control is limited by the time limitation using a timer or the like, but it is also conceivable to limit by the energy consumption such as the power consumption instead of the time limitation.

[5. Others]
As mentioned above, although embodiment of this invention was described, this invention can be implemented by changing each embodiment suitably or employ | adopting a part in the range which does not deviate from the meaning.
In each of the above embodiments, the motor 20 that also has a power generation function controls the rotational speed of the flywheel 2 (fastening element 92a), but depending on the operating state, the power generation function of the motor 20 is used, The rotational energy accumulated in the flywheel 2 can be regenerated as electric energy to control the rotational speed of the flywheel 2.

It is also conceivable to combine the first embodiment and the second embodiment. For example, the rotational speed difference increase suppression control according to the first embodiment includes that the prediction means predicts deceleration traveling as a control start condition, and this is implemented if the rotational speed difference increase suppression control is possible, When the rotational speed difference increase suppression control cannot be performed, it is conceivable to perform the pre-engagement control according to the second embodiment.
Further, as the transmission, not only a CVT (continuously variable transmission) but also a stepped transmission can be applied.

1 Engine as power source 2 Flywheel 3 Continuously variable transmission mechanism (CVT variator, variator)
3A continuously variable transmission (CVT)
4 Sub-transmission mechanism 5 Final reduction device 6 Drive wheel 7 Hydraulic circuit 8 Controller (control means)
10 Oil pump 11 Engine 1 output shaft (crankshaft)
12 Alternator 15 Battery 16 Inverter 20 Motor (electric motor)
21 Intermediate shaft 23, 24 Reduction gear train 31 CVT3 input shaft (input unit)
60 Brake Device 61 Brake Pedal 81, 82, 83 Rotational Speed Sensor 84 Vehicle Speed Sensor 85 Accelerator Pedal 86 Accelerator Opening Sensor 87 Brake Sensor 91 Engine Clutch (Friction Engaging Element)
92 Flywheel clutch 92a, 92b Engaging element (first element, second element)
100 vehicles

Claims (12)

A transmission mounted on a vehicle, having an input connected to a drive source and an output connected to drive wheels;
With flywheel,
A friction engagement element having a first element and a second element that are fastened and released from each other, wherein the first element is connected to the input of the transmission and the second element is connected to the flywheel;
A motor connected to the flywheel;
Control means for performing regenerative control for regenerating rotational energy of the drive system of the vehicle to rotational energy of the flywheel by fastening the friction engagement element during braking of the vehicle;
The control means controls the motor before fastening the frictional engagement element, and performs rotational speed difference control for reducing the rotational speed difference between the first element and the second element of the frictional engagement element. A flywheel regenerative system characterized by The rotational speed difference control is a rotational speed difference increase suppression control that controls the motor to suppress an increase in the rotational speed difference of the frictional engagement element accompanying a decrease in the rotational speed of the flywheel. The flywheel regeneration system according to claim 1. The control means sets a target rotational speed of the flywheel according to the vehicle speed of the vehicle, and when a control start condition including that the rotational speed of the flywheel is lower than the target rotational speed is satisfied, the rotational speed difference 3. The flywheel regeneration system according to claim 2, wherein the increase suppression control is started. The transmission is a continuously variable transmission, and the control means controls a transmission ratio of the transmission using a shift line corresponding to an accelerator pedal opening degree,
The flywheel according to claim 3, wherein the target rotational speed is set to a rotational speed corresponding to a rotational speed of the input unit determined according to the vehicle speed according to a shift line when the accelerator pedal is fully closed. Regenerative system. An oil pump that is driven by the rotation of the input unit of the transmission and generates a hydraulic pressure that shifts the transmission;
The shift line when the accelerator pedal is fully closed with respect to the oil amount balance securing rotational speed that is the lower limit value of the rotational speed of the input unit capable of securing the discharge flow rate of the oil pump necessary for controlling the transmission The target rotational speed is set to the oil amount balance ensuring rotational speed when the rotational speed corresponding to the rotational speed of the input unit determined according to the vehicle speed is lower in accordance with 4. The flywheel type regeneration system according to 4. 6. The control start condition includes that the vehicle is traveling with a driving force of the driving source and that the vehicle speed is equal to or lower than an upper limit vehicle speed. The flywheel type regeneration system of any one of these. The control start condition includes that the rotational speed of the flywheel is less than the target rotational speed, and that the rotational speed of the flywheel is equal to or higher than a lower limit rotational speed set according to the vehicle speed. The flywheel type regeneration system according to any one of claims 3 to 6, wherein the flywheel regeneration system is provided. The control means includes a predicting means for predicting deceleration traveling of the vehicle,
The flywheel regeneration system according to any one of claims 3 to 7, wherein the control start condition includes that the prediction unit predicts deceleration traveling. When the control start condition including that the rotational speed of the flywheel falls below the target rotational speed is satisfied during braking of the vehicle, the rotational speed difference control controls the motor to engage the friction engagement element. The flywheel regenerative system according to claim 1, wherein the flywheel regeneration system is a pre-engagement control that reduces the rotational speed difference of the friction engagement element before starting the operation. The flywheel regeneration system according to claim 9, wherein the control means performs the pre-engagement control so that the rotational speed difference of the frictional engagement element becomes zero. 10. The flywheel regeneration system according to claim 9, wherein the control means is engaged while slipping the friction engagement element after reducing the rotational speed difference by the pre-engagement control. The transmission is a continuously variable transmission, and the control means controls a transmission ratio of the transmission using a shift line corresponding to an accelerator pedal opening degree,
In addition to the vehicle being in a braking state, the regenerative control start condition is that the rotational speed of the input portion of the transmission is a rotational speed according to the shift line when the accelerator pedal is fully closed. The flywheel type regeneration system according to any one of claims 1 to 11, wherein

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