JP5960656B2 - Flywheel regeneration system and control method thereof - Google Patents

Description

  The present invention relates to a flywheel regeneration technique for regenerating kinetic energy of a vehicle with a flywheel.

  In order to improve the fuel consumption and electricity consumption of the vehicle, it is effective to regenerate the kinetic energy of the vehicle electrically or mechanically when the vehicle decelerates, and to use the regenerated energy when starting or accelerating.

  In Patent Document 1, a flywheel that can be engaged and disengaged by a clutch (hereinafter referred to as a flywheel clutch) is provided on an input shaft of a transmission, and when the vehicle decelerates, the flywheel clutch is engaged and the flywheel is rotated by rotation input from a drive wheel Is disclosed, and a flywheel regenerative system that converts vehicle kinetic energy into flywheel kinetic energy is disclosed.

  In such a flywheel regeneration system, if the flywheel clutch is released, the regenerated kinetic energy can be stored in the flywheel, and if the flywheel clutch is engaged during start-up or acceleration, it is stored in the flywheel. The released kinetic energy can be released and used for starting and accelerating the vehicle.

Special table 2012-516417 gazette

  When the vehicle powertrain has a forward clutch between the flywheel clutch and the drive wheel, it is necessary to fasten the flywheel clutch and the forward clutch when starting.

  However, if these two clutches are engaged at the same time, the heat generation rate [kW] (= engagement torque capacity x differential rotation) of the flywheel clutch increases, and if the heat generation rate exceeds the upper limit, the durability of the flywheel clutch decreases. (See FIG. 4).

  If the fastening of the forward clutch is started after the completion of the fastening of the flywheel clutch, the heat generation of the flywheel clutch can be suppressed, but the start response of the vehicle becomes worse as the fastening of the forward clutch is delayed.

  The present invention has been made in view of such a technical problem, and provides a flywheel regeneration system capable of suppressing a decrease in start response of a vehicle while suppressing heat generation of a flywheel clutch at the time of start. Objective.

  According to an aspect of the present invention, a flywheel, a flywheel clutch provided in a power transmission path from the flywheel to the drive wheel, and between the flywheel clutch and the drive wheel in the power transmission path A flywheel regenerative system that engages the flywheel clutch to regenerate kinetic energy of the vehicle during vehicle deceleration, wherein the flywheel clutch and the forward clutch are released When the flywheel clutch and the forward clutch are fastened to start the vehicle, the flywheel clutch and the forward clutch are started in this order, and the forward start timing of the forward clutch is set to the heat generation of the flywheel clutch. After the maximum rate and the flywheel Flywheel regenerative system comprising a start control means for setting prior to when the clutch is fully engaged is provided.

  Moreover, according to another aspect of this invention, the control method of the said flywheel regeneration system is provided.

  According to these aspects, it is possible to suppress a decrease in start response while suppressing a decrease in durability by suppressing heat generation of the flywheel clutch.

It is a whole lineblock diagram of vehicles provided with a flywheel regeneration system. It is the flowchart which showed the contents of start control. It is a time chart which showed the mode at the time of start. It is a time chart which showed the mode at the time of the start of a comparative example.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, “starting” includes starting from a vehicle speed of zero and reacceleration from a state in which the vehicle does not stop completely.

  FIG. 1 shows an overall configuration of a vehicle 100 including a flywheel regeneration system according to an embodiment of the present invention.

  The vehicle 100 decelerates the output rotation of the engine 1 as a power source, a flywheel 2 for regeneration, a continuously variable transmission (hereinafter referred to as CVT) 3 that continuously changes the output rotation of the engine 1, and the CVT 3. A final reduction gear 4, a differential 5, left and right drive wheels 6, a hydraulic circuit 7, and a controller 8 are provided.

  An engine clutch CL1 is provided between the engine 1 and the input shaft 3in of the CVT 3. The engine clutch CL1 is a hydraulic clutch capable of controlling the fastening torque capacity with supplied hydraulic pressure.

  Between the CVT 3 and the final reduction gear 4, there is provided a forward clutch CL2 that is fastened when starting and moving forward and transmits the rotation from the engine 1 or the flywheel 2 input via the CVT 3 to the final reduction gear 4. Yes. The forward clutch CL2 is a hydraulic clutch whose fastening torque capacity can be controlled by supplied hydraulic pressure. The forward clutch CL2 is provided alone in FIG. 1, but more specifically, a clutch (including a brake) that realizes a forward state in a stepped transmission or a forward / reverse switching mechanism provided between the CVT 3 and the final reduction gear 4. )one of.

  An oil pump 10 is connected to the input shaft 3in of the CVT 3 via a belt, a gear, etc. (not shown). The oil pump 10 is a gear pump type or vane pump type oil pump that generates hydraulic pressure when the input shaft 3in of the CVT 3 rotates. The hydraulic pressure generated by the oil pump 10 is sent to a hydraulic circuit 7 described later, and is supplied from the hydraulic circuit 7 to the pulley of the CVT 3, the engine clutch CL1, and the forward clutch CL2.

  The flywheel 2 is further connected to the input shaft 3 in of the CVT 3 via a pair of reduction gear trains 11 and 12. The flywheel 2 is a metal cylinder or disk, and is housed in a container that is vacuumed or decompressed to reduce windage loss during rotation.

  A flywheel clutch CLfw is provided between the reduction gear train 11 and the reduction gear train 12. The flywheel clutch CLfw is an electric clutch that can be switched between engagement and disengagement by the clutch actuator 13. An electric oil pump may be provided instead of the clutch actuator 13, and the flywheel clutch CLfw may be a hydraulic clutch capable of controlling the fastening torque capacity by the hydraulic pressure generated by the electric oil pump.

  The hydraulic circuit 7 includes a solenoid valve that operates in response to a signal from a controller 8 to be described later, and is connected to the CVT 3, the engine clutch CL1, the forward clutch CL2, and the oil pump 10 through an oil passage. The hydraulic circuit 7 generates the hydraulic pressure required by the pulley of the CVT 3, the engine clutch CL 1, and the forward clutch CL 2 using the hydraulic pressure generated by the oil pump 10 as the original pressure, and the generated hydraulic pressure is used as the pulley of the CVT 3, the engine clutch CL 1 Supply to forward clutch CL2.

  The brake 14 is an electronically controlled brake in which the brake pedal 15 and the master cylinder 16 are mechanically independent. When the driver depresses the brake pedal 15, the brake actuator 17 displaces the piston of the master cylinder 16, and hydraulic pressure corresponding to the required deceleration (deceleration requested by the driver, the same applies hereinafter) is supplied to the brake 14. Power is generated. Although not shown, the brake 14 is also provided on the driven wheel.

  The controller 8 includes a CPU, a RAM, an input / output interface, and the like. The controller 8 includes a rotation speed sensor 21 that detects the rotation speed of the engine 1, and a rotation speed sensor 22 that detects the rotation speed Nin of the input shaft 3in of the CVT 3. , A rotational speed sensor 23 for detecting the rotational speed Nfw of the flywheel 2, a vehicle speed sensor 24 for detecting the vehicle speed VSP, an accelerator opening sensor 26 for detecting the opening APO of the accelerator pedal 25, and the depression amount of the brake pedal 15 by the driver And the signal from the brake sensor 27 etc. which detects depression acceleration is input.

  The controller 8 performs various calculations based on the input signal, and controls the shift of the CVT 3, the engagement / release of the clutches CL1, CL2, and CLfw, and the brake actuator 17. In particular, when the driver depresses the brake pedal 15 and the vehicle 100 decelerates, the controller 8 fastens the flywheel clutch CLfw and the forward clutch CL2, and rotates the flywheel 2 by the rotation input from the drive wheels 6. The kinetic energy of the vehicle 100 is regenerated by converting the kinetic energy of the vehicle 100 into the kinetic energy of the flywheel 2.

  During regeneration, the controller 8 calculates the required deceleration with reference to a predetermined map based on the depression amount and depression acceleration of the brake pedal 15 detected by the brake sensor 27, the vehicle speed VSP, etc., and responds to the required deceleration. The engagement torque capacity of the flywheel clutch CLfw is controlled so that a braking force (regenerative brake) is obtained. When the regenerative brake cannot be generated before the flywheel clutch CLfw is engaged, or when the required deceleration cannot be realized only with the regenerative brake, the controller 8 operates the brake actuator 17 to increase the braking force of the brake 14 to reduce the request. Let speed be realized.

  The regenerated kinetic energy can be stored in the flywheel 2 by releasing the flywheel clutch CLfw. If the flywheel clutch CLfw is engaged in a state where kinetic energy is stored in the flywheel 2, the kinetic energy stored in the flywheel 2 can be used for starting and acceleration of the vehicle 100.

  By the way, when starting the vehicle 100 with the kinetic energy preserve | saved at the flywheel 2, in addition to the flywheel clutch CLfw, it is necessary to fasten the forward clutch CL2, but the order which fastens these two friction elements is a flywheel. The order is the clutch CLfw and the forward clutch CL2.

  This is because the oil pump 10 is not driven unless the flywheel clutch CLfw is fastened first, and the hydraulic pressure required to fasten the forward clutch CL2 cannot be supplied to the forward clutch CL2.

  Moreover, it is for preventing the durability of flywheel clutch CLfw falling. When the forward clutch CL2 and the flywheel clutch CLfw are engaged in this order, the inertia when the flywheel clutch CLfw is engaged becomes all the members from the output side element of the flywheel clutch CLfw to the drive wheel 6, and the flywheel clutch CLfw when the flywheel clutch CLfw is engaged. The burden of is great. If the flywheel clutch CLfw is fastened first, the inertia when the flywheel clutch CLfw is fastened becomes smaller by the final reduction gear 4, the differential gear 5 and the drive wheel 6 and therefore the flywheel clutch CLfw when the flywheel clutch CLfw is fastened The burden can be reduced.

  Further, in the present embodiment, the start control described below is performed, thereby suppressing the heat generation (particularly, the heat generation rate) of the flywheel clutch CLfw and preventing the durability of the flywheel clutch CLfw from being lowered.

  FIG. 2 is a flowchart showing the contents of the start control performed by the controller 8.

  As a premise for performing the start control, it is necessary that the kinetic energy necessary to start the vehicle 100 is stored in the flywheel 2, and the vehicle 100 can be started from the rotational speed Nfw of the flywheel 2. It is executed when it is determined.

  According to this, first, in S11, the controller 8 determines whether or not there is a start request of the vehicle 100 based on signals input from the vehicle speed sensor 24, the accelerator opening sensor 26, and the brake sensor 27. The start request is when the vehicle 100 is started with the foot released from the brake pedal 15 when the vehicle speed is zero, or when the accelerator pedal 25 is depressed before the vehicle 100 stops and the vehicle 100 is reaccelerated. It is judged that there is. If it is determined that there is a start request, the process proceeds to S12 in order to start the vehicle 100 using the kinetic energy stored in the flywheel clutch CLfw. If it is determined that there is no start request, there is no need to start the vehicle 100, and the process ends.

  In S12, the controller 8 increases the engagement torque capacity of the flywheel clutch CLfw. As a result, the heat generation rate (power) [kW] of the flywheel clutch CLfw determined by the product of the engagement torque capacity and the differential rotation of the input side element and the output side element also increases.

  In S13, the controller 8 determines whether the heat generation rate of the flywheel clutch CLfw is maximized based on whether the change rate is substantially zero. Such a determination is possible because the heat generation rate of the flywheel clutch CLfw tends to increase as the engagement torque capacity of the flywheel clutch CLfw increases and decreases as the slip rate converges. This is because the rate of change becomes zero where the heat generation rate is maximum.

  When it is determined that the rate of change in the heat generation rate of the flywheel clutch CLfw (the amount of change in a minute time) is substantially zero and the heat generation rate of the flywheel clutch CLfw is maximized, the process proceeds to S14. If not, the process returns to S12 to further increase the engagement torque capacity of the flywheel clutch CLfw.

  In S14, the controller 8 increases the engagement torque capacity of the forward clutch CL2 and starts the engagement of the forward clutch CL2.

  In S15, the controller 8 controls the engagement torque capacity of the flywheel clutch CLfw. Specifically, the controller 8 controls the engagement torque capacity of the flywheel clutch CLfw so that the engagement torque capacity of the flywheel clutch CLfw is larger than the engagement torque capacity of the forward clutch CL2, and the flywheel clutch CLfw moves forward. The clutch CL2 is defeated so as not to slip.

  In S16, the controller 8 determines whether or not the engagement of the flywheel clutch CLfw has been completed. If the engagement of the flywheel clutch CLfw has not been completed, the process proceeds to S17.

  In S17, the controller 8 determines whether the heat generation rate of the flywheel clutch CLfw has reached the upper limit. The upper limit is set to a value slightly lower than the heat generation rate at which the flywheel clutch CLfw burns out (= burnout heat generation rate-margin).

  When the heat generation rate of the flywheel clutch CLfw has reached the upper limit, the process proceeds to S18, the respective engagement torque capacities of the flywheel clutch CLfw and the forward clutch CL2 are maintained at the current values, and the flywheel clutch CLfw The processes of S17 and S18 are repeated until the heat generation rate becomes smaller than the upper limit value, and the process waits.

  If the heat generation rate of the flywheel clutch CLfw has not reached the upper limit, the process returns to S14, and the engagement torque capacity of the forward clutch CL2 is further increased. As a result, the engagement torque capacity of the forward clutch CL2 can be increased to the maximum as long as the heat generation rate of the flywheel clutch CLfw does not exceed the upper limit.

  On the other hand, if it is determined in S16 that the engagement of the flywheel clutch CLfw has been completed, there is no need to consider the heat generation of the flywheel clutch CLfw, so the process proceeds to S19 and the engagement of the forward clutch CL2 is completed. The engagement torque capacity of the forward clutch CL2 is repeatedly increased (S19, S20) until the engagement is completed, and the process ends when the engagement of the forward clutch CL2 is completed.

  Then, the effect by performing the said start control is demonstrated.

  FIG. 3 is a time chart showing a state at the time of starting in the case of performing the starting control.

  At time t11, the engagement of the flywheel clutch CLfw is started. When the flywheel clutch CLfw is engaged, the oil pressure required for the forward clutch CL2 to be engaged after the oil pump 10 is driven can be ensured. Further, since the forward clutch CL2 is released and the final speed reduction device 4, the differential device 5 and the drive wheel 6 are disconnected, the inertia of the portion where rotation starts when the flywheel clutch CLfw is engaged is reduced. The burden on the wheel clutch CLfw can be suppressed.

  As the engagement torque capacity of the flywheel clutch CLfw increases, the heat generation rate of the flywheel clutch CLfw increases, and when it reaches the maximum at time t12, the engagement of the forward clutch CL2 is started.

  After time t12, the engagement torque capacity of the forward clutch CL2 increases, but the time when the heat generation rate of the flywheel clutch CLfw reaches the maximum has passed, and the increase of the engagement torque capacity of the forward clutch CL2 Since it is performed so as not to exceed the upper limit of the heat generation rate, the heat generation rate of the flywheel clutch CLfw does not exceed the upper limit.

  Note that the increase speed of the engagement torque capacity of the flywheel clutch CLfw is increased after time t12 because the engagement torque capacity of the flywheel clutch CLfw is controlled so as not to fall below the engagement torque capacity of the forward clutch CL2. It is.

  Since the fastening of the forward clutch CL2 is started before the fastening of the flywheel clutch CLfw is completed, and the fastening torque capacity of the forward clutch CL2 is repeatedly increased while the heat generation rate of the flywheel clutch CLfw does not reach the upper limit, A decrease in start response due to a delay in the start of engagement of the forward clutch CL2 with respect to the flywheel clutch CLfw can be minimized.

  At time t13, the input side rotational speed and the output side rotational speed of the flywheel clutch CLfw coincide with each other, and the engagement of the flywheel clutch CLfw is completed. After time t13, the engagement torque capacity is increased until the forward clutch CL2 is engaged. However, since the flywheel clutch CLfw has already been engaged, its heat generation does not cause a problem.

  As described above, in the present embodiment, when the flywheel clutch CLfw and the forward clutch CL2 are released and the flywheel clutch CLfw and the forward clutch CL2 are fastened to start the vehicle 100, the flywheel clutch CLfw and the forward clutch The engagement was started in the order of CL2, and the engagement start timing of the forward clutch CL2 was set after the time when the heat generation rate of the flywheel clutch CLfw is maximized and before the flywheel clutch CLfw is completely engaged. Accordingly, it is possible to suppress a decrease in start response while suppressing a decrease in durability by suppressing heat generation of the flywheel clutch CLfw (effect corresponding to claims 1 and 4).

  Further, based on the rate of change of the heat generation rate of the flywheel clutch CLfw, it is determined whether or not the heat generation rate of the flywheel clutch CLfw is maximized. Accordingly, it is possible to accurately determine when the heat generation rate of the flywheel clutch CLfw is maximized, and to start the engagement of the forward clutch CL2 after the time when the heat generation rate of the flywheel clutch CLfw is maximized. Corresponding effect).

  Whether or not the heat generation rate of the flywheel clutch CLfw is maximized is determined by determining whether the change rate of the heat generation rate of the flywheel clutch CLfw has become substantially zero, and preferably by determining whether it has become zero.

  If the forward clutch CL2 is engaged before the change rate of the heat generation rate of the flywheel clutch CLfw becomes zero, the heat generation rate of the flywheel clutch CLfw exceeds the upper limit and the durability of the flywheel clutch CLfw is reduced to zero. When the operation is started after the time is reached, there is a period in which the forward clutch CL2 is not engaged even though the heat generation rate of the flywheel clutch CLfw has a margin with respect to the upper limit, and the start response is deteriorated. These problems can be prevented by determining that the heat generation rate of the rywheel clutch CLfw is maximized when the change rate of the heat generation rate of the flywheel clutch CLfw is zero and starting the engagement of the forward clutch CL2. .

  Further, until the flywheel clutch CLfw is completely engaged, it is determined whether the heat generation rate of the flywheel clutch CLfw has reached the upper limit, and if not, the increase in the engagement torque capacity of the forward clutch Cl2 is repeated. did. Thereby, the time until the forward clutch CL2 completes the engagement can be shortened, and the deterioration of the start response can be further suppressed (effect corresponding to claim 3).

  The embodiment of the present invention has been described above, but the above embodiment is merely a part of an application example of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. is not.

  For example, in the above embodiment, the vehicle 100 includes only the engine 1 as a power source. However, the vehicle 100 may include the engine 1 and a motor as power sources, or may include only a motor instead of the engine 1. Good.

  Although vehicle 100 includes CVT 3 as a transmission, the type of transmission is not limited thereto, and may include a stepped transmission instead of CVT 3.

1 Engine 2 Flywheel 3 CVT (Transmission)
3in input shaft 8 controller (start control means)
10 Oil pump CL1 Engine clutch CL2 Forward clutch CLfw Flywheel clutch

Claims (4)

A flywheel, a flywheel clutch provided in a power transmission path from the flywheel to the drive wheel, and a forward clutch provided between the flywheel clutch and the drive wheel in the power transmission path, A flywheel regeneration system for regenerating kinetic energy of the vehicle by engaging the flywheel clutch during vehicle deceleration,
When the flywheel clutch and the forward clutch are released from the released state and the flywheel clutch and the forward clutch are engaged to start the vehicle, the flywheel clutch and the forward clutch are started in this order. A start control means for setting a forward clutch engagement start time after the flywheel clutch has a maximum heat generation rate and before the flywheel clutch is completely engaged;
A flywheel regenerative system characterized by comprising: The flywheel regeneration system according to claim 1,
The start control means determines whether the heat generation rate of the flywheel clutch is maximized based on the change rate of the heat generation rate of the flywheel clutch.
A flywheel regeneration system characterized by that. The flywheel regeneration system according to claim 1 or 2,
The start control means determines whether the heat generation rate of the flywheel clutch has not reached the upper limit until the flywheel clutch is completely engaged, and increases the engagement torque capacity of the forward clutch if not reached. To
A flywheel regeneration system characterized by that. A flywheel, a flywheel clutch provided in a power transmission path from the flywheel to the drive wheel, and a forward clutch provided between the flywheel clutch and the drive wheel in the power transmission path, A control method of a flywheel regeneration system for regenerating the kinetic energy of the vehicle by engaging the flywheel clutch during vehicle deceleration,
When the flywheel clutch and the forward clutch are released from the released state and the flywheel clutch and the forward clutch are engaged to start the vehicle, the flywheel clutch and the forward clutch are started in this order. The forward clutch engagement start time is set after the time when the heat generation rate of the flywheel clutch is maximized and before the flywheel clutch is fully engaged,
A control method for a flywheel regenerative system.

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